xref: /sqlite-3.40.0/src/vdbe.c (revision e89feee5)
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** The code in this file implements the function that runs the
13 ** bytecode of a prepared statement.
14 **
15 ** Various scripts scan this source file in order to generate HTML
16 ** documentation, headers files, or other derived files.  The formatting
17 ** of the code in this file is, therefore, important.  See other comments
18 ** in this file for details.  If in doubt, do not deviate from existing
19 ** commenting and indentation practices when changing or adding code.
20 */
21 #include "sqliteInt.h"
22 #include "vdbeInt.h"
23 
24 /*
25 ** Invoke this macro on memory cells just prior to changing the
26 ** value of the cell.  This macro verifies that shallow copies are
27 ** not misused.  A shallow copy of a string or blob just copies a
28 ** pointer to the string or blob, not the content.  If the original
29 ** is changed while the copy is still in use, the string or blob might
30 ** be changed out from under the copy.  This macro verifies that nothing
31 ** like that ever happens.
32 */
33 #ifdef SQLITE_DEBUG
34 # define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
35 #else
36 # define memAboutToChange(P,M)
37 #endif
38 
39 /*
40 ** The following global variable is incremented every time a cursor
41 ** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
42 ** procedures use this information to make sure that indices are
43 ** working correctly.  This variable has no function other than to
44 ** help verify the correct operation of the library.
45 */
46 #ifdef SQLITE_TEST
47 int sqlite3_search_count = 0;
48 #endif
49 
50 /*
51 ** When this global variable is positive, it gets decremented once before
52 ** each instruction in the VDBE.  When it reaches zero, the u1.isInterrupted
53 ** field of the sqlite3 structure is set in order to simulate an interrupt.
54 **
55 ** This facility is used for testing purposes only.  It does not function
56 ** in an ordinary build.
57 */
58 #ifdef SQLITE_TEST
59 int sqlite3_interrupt_count = 0;
60 #endif
61 
62 /*
63 ** The next global variable is incremented each type the OP_Sort opcode
64 ** is executed.  The test procedures use this information to make sure that
65 ** sorting is occurring or not occurring at appropriate times.   This variable
66 ** has no function other than to help verify the correct operation of the
67 ** library.
68 */
69 #ifdef SQLITE_TEST
70 int sqlite3_sort_count = 0;
71 #endif
72 
73 /*
74 ** The next global variable records the size of the largest MEM_Blob
75 ** or MEM_Str that has been used by a VDBE opcode.  The test procedures
76 ** use this information to make sure that the zero-blob functionality
77 ** is working correctly.   This variable has no function other than to
78 ** help verify the correct operation of the library.
79 */
80 #ifdef SQLITE_TEST
81 int sqlite3_max_blobsize = 0;
82 static void updateMaxBlobsize(Mem *p){
83   if( (p->flags & (MEM_Str|MEM_Blob))!=0 && p->n>sqlite3_max_blobsize ){
84     sqlite3_max_blobsize = p->n;
85   }
86 }
87 #endif
88 
89 /*
90 ** This macro evaluates to true if either the update hook or the preupdate
91 ** hook are enabled for database connect DB.
92 */
93 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
94 # define HAS_UPDATE_HOOK(DB) ((DB)->xPreUpdateCallback||(DB)->xUpdateCallback)
95 #else
96 # define HAS_UPDATE_HOOK(DB) ((DB)->xUpdateCallback)
97 #endif
98 
99 /*
100 ** The next global variable is incremented each time the OP_Found opcode
101 ** is executed. This is used to test whether or not the foreign key
102 ** operation implemented using OP_FkIsZero is working. This variable
103 ** has no function other than to help verify the correct operation of the
104 ** library.
105 */
106 #ifdef SQLITE_TEST
107 int sqlite3_found_count = 0;
108 #endif
109 
110 /*
111 ** Test a register to see if it exceeds the current maximum blob size.
112 ** If it does, record the new maximum blob size.
113 */
114 #if defined(SQLITE_TEST) && !defined(SQLITE_UNTESTABLE)
115 # define UPDATE_MAX_BLOBSIZE(P)  updateMaxBlobsize(P)
116 #else
117 # define UPDATE_MAX_BLOBSIZE(P)
118 #endif
119 
120 /*
121 ** Invoke the VDBE coverage callback, if that callback is defined.  This
122 ** feature is used for test suite validation only and does not appear an
123 ** production builds.
124 **
125 ** M is an integer between 2 and 4.  2 indicates a ordinary two-way
126 ** branch (I=0 means fall through and I=1 means taken).  3 indicates
127 ** a 3-way branch where the third way is when one of the operands is
128 ** NULL.  4 indicates the OP_Jump instruction which has three destinations
129 ** depending on whether the first operand is less than, equal to, or greater
130 ** than the second.
131 **
132 ** iSrcLine is the source code line (from the __LINE__ macro) that
133 ** generated the VDBE instruction combined with flag bits.  The source
134 ** code line number is in the lower 24 bits of iSrcLine and the upper
135 ** 8 bytes are flags.  The lower three bits of the flags indicate
136 ** values for I that should never occur.  For example, if the branch is
137 ** always taken, the flags should be 0x05 since the fall-through and
138 ** alternate branch are never taken.  If a branch is never taken then
139 ** flags should be 0x06 since only the fall-through approach is allowed.
140 **
141 ** Bit 0x04 of the flags indicates an OP_Jump opcode that is only
142 ** interested in equal or not-equal.  In other words, I==0 and I==2
143 ** should be treated the same.
144 **
145 ** Since only a line number is retained, not the filename, this macro
146 ** only works for amalgamation builds.  But that is ok, since these macros
147 ** should be no-ops except for special builds used to measure test coverage.
148 */
149 #if !defined(SQLITE_VDBE_COVERAGE)
150 # define VdbeBranchTaken(I,M)
151 #else
152 # define VdbeBranchTaken(I,M) vdbeTakeBranch(pOp->iSrcLine,I,M)
153   static void vdbeTakeBranch(u32 iSrcLine, u8 I, u8 M){
154     u8 mNever;
155     assert( I<=2 );  /* 0: fall through,  1: taken,  2: alternate taken */
156     assert( M<=4 );  /* 2: two-way branch, 3: three-way branch, 4: OP_Jump */
157     assert( I<M );   /* I can only be 2 if M is 3 or 4 */
158     /* Transform I from a integer [0,1,2] into a bitmask of [1,2,4] */
159     I = 1<<I;
160     /* The upper 8 bits of iSrcLine are flags.  The lower three bits of
161     ** the flags indicate directions that the branch can never go.  If
162     ** a branch really does go in one of those directions, assert right
163     ** away. */
164     mNever = iSrcLine >> 24;
165     assert( (I & mNever)==0 );
166     if( sqlite3GlobalConfig.xVdbeBranch==0 ) return;  /*NO_TEST*/
167     I |= mNever;
168     if( M==2 ) I |= 0x04;
169     if( M==4 ){
170       I |= 0x08;
171       if( (mNever&0x08)!=0 && (I&0x05)!=0) I |= 0x05; /*NO_TEST*/
172     }
173     sqlite3GlobalConfig.xVdbeBranch(sqlite3GlobalConfig.pVdbeBranchArg,
174                                     iSrcLine&0xffffff, I, M);
175   }
176 #endif
177 
178 /*
179 ** Convert the given register into a string if it isn't one
180 ** already. Return non-zero if a malloc() fails.
181 */
182 #define Stringify(P, enc) \
183    if(((P)->flags&(MEM_Str|MEM_Blob))==0 && sqlite3VdbeMemStringify(P,enc,0)) \
184      { goto no_mem; }
185 
186 /*
187 ** An ephemeral string value (signified by the MEM_Ephem flag) contains
188 ** a pointer to a dynamically allocated string where some other entity
189 ** is responsible for deallocating that string.  Because the register
190 ** does not control the string, it might be deleted without the register
191 ** knowing it.
192 **
193 ** This routine converts an ephemeral string into a dynamically allocated
194 ** string that the register itself controls.  In other words, it
195 ** converts an MEM_Ephem string into a string with P.z==P.zMalloc.
196 */
197 #define Deephemeralize(P) \
198    if( ((P)->flags&MEM_Ephem)!=0 \
199        && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}
200 
201 /* Return true if the cursor was opened using the OP_OpenSorter opcode. */
202 #define isSorter(x) ((x)->eCurType==CURTYPE_SORTER)
203 
204 /*
205 ** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
206 ** if we run out of memory.
207 */
208 static VdbeCursor *allocateCursor(
209   Vdbe *p,              /* The virtual machine */
210   int iCur,             /* Index of the new VdbeCursor */
211   int nField,           /* Number of fields in the table or index */
212   int iDb,              /* Database the cursor belongs to, or -1 */
213   u8 eCurType           /* Type of the new cursor */
214 ){
215   /* Find the memory cell that will be used to store the blob of memory
216   ** required for this VdbeCursor structure. It is convenient to use a
217   ** vdbe memory cell to manage the memory allocation required for a
218   ** VdbeCursor structure for the following reasons:
219   **
220   **   * Sometimes cursor numbers are used for a couple of different
221   **     purposes in a vdbe program. The different uses might require
222   **     different sized allocations. Memory cells provide growable
223   **     allocations.
224   **
225   **   * When using ENABLE_MEMORY_MANAGEMENT, memory cell buffers can
226   **     be freed lazily via the sqlite3_release_memory() API. This
227   **     minimizes the number of malloc calls made by the system.
228   **
229   ** The memory cell for cursor 0 is aMem[0]. The rest are allocated from
230   ** the top of the register space.  Cursor 1 is at Mem[p->nMem-1].
231   ** Cursor 2 is at Mem[p->nMem-2]. And so forth.
232   */
233   Mem *pMem = iCur>0 ? &p->aMem[p->nMem-iCur] : p->aMem;
234 
235   int nByte;
236   VdbeCursor *pCx = 0;
237   nByte =
238       ROUND8(sizeof(VdbeCursor)) + 2*sizeof(u32)*nField +
239       (eCurType==CURTYPE_BTREE?sqlite3BtreeCursorSize():0);
240 
241   assert( iCur>=0 && iCur<p->nCursor );
242   if( p->apCsr[iCur] ){ /*OPTIMIZATION-IF-FALSE*/
243     sqlite3VdbeFreeCursor(p, p->apCsr[iCur]);
244     p->apCsr[iCur] = 0;
245   }
246   if( SQLITE_OK==sqlite3VdbeMemClearAndResize(pMem, nByte) ){
247     p->apCsr[iCur] = pCx = (VdbeCursor*)pMem->z;
248     memset(pCx, 0, offsetof(VdbeCursor,pAltCursor));
249     pCx->eCurType = eCurType;
250     pCx->iDb = iDb;
251     pCx->nField = nField;
252     pCx->aOffset = &pCx->aType[nField];
253     if( eCurType==CURTYPE_BTREE ){
254       pCx->uc.pCursor = (BtCursor*)
255           &pMem->z[ROUND8(sizeof(VdbeCursor))+2*sizeof(u32)*nField];
256       sqlite3BtreeCursorZero(pCx->uc.pCursor);
257     }
258   }
259   return pCx;
260 }
261 
262 /*
263 ** Try to convert a value into a numeric representation if we can
264 ** do so without loss of information.  In other words, if the string
265 ** looks like a number, convert it into a number.  If it does not
266 ** look like a number, leave it alone.
267 **
268 ** If the bTryForInt flag is true, then extra effort is made to give
269 ** an integer representation.  Strings that look like floating point
270 ** values but which have no fractional component (example: '48.00')
271 ** will have a MEM_Int representation when bTryForInt is true.
272 **
273 ** If bTryForInt is false, then if the input string contains a decimal
274 ** point or exponential notation, the result is only MEM_Real, even
275 ** if there is an exact integer representation of the quantity.
276 */
277 static void applyNumericAffinity(Mem *pRec, int bTryForInt){
278   double rValue;
279   i64 iValue;
280   u8 enc = pRec->enc;
281   assert( (pRec->flags & (MEM_Str|MEM_Int|MEM_Real))==MEM_Str );
282   if( sqlite3AtoF(pRec->z, &rValue, pRec->n, enc)==0 ) return;
283   if( 0==sqlite3Atoi64(pRec->z, &iValue, pRec->n, enc) ){
284     pRec->u.i = iValue;
285     pRec->flags |= MEM_Int;
286   }else{
287     pRec->u.r = rValue;
288     pRec->flags |= MEM_Real;
289     if( bTryForInt ) sqlite3VdbeIntegerAffinity(pRec);
290   }
291   /* TEXT->NUMERIC is many->one.  Hence, it is important to invalidate the
292   ** string representation after computing a numeric equivalent, because the
293   ** string representation might not be the canonical representation for the
294   ** numeric value.  Ticket [343634942dd54ab57b7024] 2018-01-31. */
295   pRec->flags &= ~MEM_Str;
296 }
297 
298 /*
299 ** Processing is determine by the affinity parameter:
300 **
301 ** SQLITE_AFF_INTEGER:
302 ** SQLITE_AFF_REAL:
303 ** SQLITE_AFF_NUMERIC:
304 **    Try to convert pRec to an integer representation or a
305 **    floating-point representation if an integer representation
306 **    is not possible.  Note that the integer representation is
307 **    always preferred, even if the affinity is REAL, because
308 **    an integer representation is more space efficient on disk.
309 **
310 ** SQLITE_AFF_TEXT:
311 **    Convert pRec to a text representation.
312 **
313 ** SQLITE_AFF_BLOB:
314 **    No-op.  pRec is unchanged.
315 */
316 static void applyAffinity(
317   Mem *pRec,          /* The value to apply affinity to */
318   char affinity,      /* The affinity to be applied */
319   u8 enc              /* Use this text encoding */
320 ){
321   if( affinity>=SQLITE_AFF_NUMERIC ){
322     assert( affinity==SQLITE_AFF_INTEGER || affinity==SQLITE_AFF_REAL
323              || affinity==SQLITE_AFF_NUMERIC );
324     if( (pRec->flags & MEM_Int)==0 ){ /*OPTIMIZATION-IF-FALSE*/
325       if( (pRec->flags & MEM_Real)==0 ){
326         if( pRec->flags & MEM_Str ) applyNumericAffinity(pRec,1);
327       }else{
328         sqlite3VdbeIntegerAffinity(pRec);
329       }
330     }
331   }else if( affinity==SQLITE_AFF_TEXT ){
332     /* Only attempt the conversion to TEXT if there is an integer or real
333     ** representation (blob and NULL do not get converted) but no string
334     ** representation.  It would be harmless to repeat the conversion if
335     ** there is already a string rep, but it is pointless to waste those
336     ** CPU cycles. */
337     if( 0==(pRec->flags&MEM_Str) ){ /*OPTIMIZATION-IF-FALSE*/
338       if( (pRec->flags&(MEM_Real|MEM_Int)) ){
339         sqlite3VdbeMemStringify(pRec, enc, 1);
340       }
341     }
342     pRec->flags &= ~(MEM_Real|MEM_Int);
343   }
344 }
345 
346 /*
347 ** Try to convert the type of a function argument or a result column
348 ** into a numeric representation.  Use either INTEGER or REAL whichever
349 ** is appropriate.  But only do the conversion if it is possible without
350 ** loss of information and return the revised type of the argument.
351 */
352 int sqlite3_value_numeric_type(sqlite3_value *pVal){
353   int eType = sqlite3_value_type(pVal);
354   if( eType==SQLITE_TEXT ){
355     Mem *pMem = (Mem*)pVal;
356     applyNumericAffinity(pMem, 0);
357     eType = sqlite3_value_type(pVal);
358   }
359   return eType;
360 }
361 
362 /*
363 ** Exported version of applyAffinity(). This one works on sqlite3_value*,
364 ** not the internal Mem* type.
365 */
366 void sqlite3ValueApplyAffinity(
367   sqlite3_value *pVal,
368   u8 affinity,
369   u8 enc
370 ){
371   applyAffinity((Mem *)pVal, affinity, enc);
372 }
373 
374 /*
375 ** pMem currently only holds a string type (or maybe a BLOB that we can
376 ** interpret as a string if we want to).  Compute its corresponding
377 ** numeric type, if has one.  Set the pMem->u.r and pMem->u.i fields
378 ** accordingly.
379 */
380 static u16 SQLITE_NOINLINE computeNumericType(Mem *pMem){
381   assert( (pMem->flags & (MEM_Int|MEM_Real))==0 );
382   assert( (pMem->flags & (MEM_Str|MEM_Blob))!=0 );
383   if( sqlite3AtoF(pMem->z, &pMem->u.r, pMem->n, pMem->enc)==0 ){
384     return 0;
385   }
386   if( sqlite3Atoi64(pMem->z, &pMem->u.i, pMem->n, pMem->enc)==0 ){
387     return MEM_Int;
388   }
389   return MEM_Real;
390 }
391 
392 /*
393 ** Return the numeric type for pMem, either MEM_Int or MEM_Real or both or
394 ** none.
395 **
396 ** Unlike applyNumericAffinity(), this routine does not modify pMem->flags.
397 ** But it does set pMem->u.r and pMem->u.i appropriately.
398 */
399 static u16 numericType(Mem *pMem){
400   if( pMem->flags & (MEM_Int|MEM_Real) ){
401     return pMem->flags & (MEM_Int|MEM_Real);
402   }
403   if( pMem->flags & (MEM_Str|MEM_Blob) ){
404     return computeNumericType(pMem);
405   }
406   return 0;
407 }
408 
409 #ifdef SQLITE_DEBUG
410 /*
411 ** Write a nice string representation of the contents of cell pMem
412 ** into buffer zBuf, length nBuf.
413 */
414 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf){
415   char *zCsr = zBuf;
416   int f = pMem->flags;
417 
418   static const char *const encnames[] = {"(X)", "(8)", "(16LE)", "(16BE)"};
419 
420   if( f&MEM_Blob ){
421     int i;
422     char c;
423     if( f & MEM_Dyn ){
424       c = 'z';
425       assert( (f & (MEM_Static|MEM_Ephem))==0 );
426     }else if( f & MEM_Static ){
427       c = 't';
428       assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
429     }else if( f & MEM_Ephem ){
430       c = 'e';
431       assert( (f & (MEM_Static|MEM_Dyn))==0 );
432     }else{
433       c = 's';
434     }
435     *(zCsr++) = c;
436     sqlite3_snprintf(100, zCsr, "%d[", pMem->n);
437     zCsr += sqlite3Strlen30(zCsr);
438     for(i=0; i<16 && i<pMem->n; i++){
439       sqlite3_snprintf(100, zCsr, "%02X", ((int)pMem->z[i] & 0xFF));
440       zCsr += sqlite3Strlen30(zCsr);
441     }
442     for(i=0; i<16 && i<pMem->n; i++){
443       char z = pMem->z[i];
444       if( z<32 || z>126 ) *zCsr++ = '.';
445       else *zCsr++ = z;
446     }
447     *(zCsr++) = ']';
448     if( f & MEM_Zero ){
449       sqlite3_snprintf(100, zCsr,"+%dz",pMem->u.nZero);
450       zCsr += sqlite3Strlen30(zCsr);
451     }
452     *zCsr = '\0';
453   }else if( f & MEM_Str ){
454     int j, k;
455     zBuf[0] = ' ';
456     if( f & MEM_Dyn ){
457       zBuf[1] = 'z';
458       assert( (f & (MEM_Static|MEM_Ephem))==0 );
459     }else if( f & MEM_Static ){
460       zBuf[1] = 't';
461       assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
462     }else if( f & MEM_Ephem ){
463       zBuf[1] = 'e';
464       assert( (f & (MEM_Static|MEM_Dyn))==0 );
465     }else{
466       zBuf[1] = 's';
467     }
468     k = 2;
469     sqlite3_snprintf(100, &zBuf[k], "%d", pMem->n);
470     k += sqlite3Strlen30(&zBuf[k]);
471     zBuf[k++] = '[';
472     for(j=0; j<15 && j<pMem->n; j++){
473       u8 c = pMem->z[j];
474       if( c>=0x20 && c<0x7f ){
475         zBuf[k++] = c;
476       }else{
477         zBuf[k++] = '.';
478       }
479     }
480     zBuf[k++] = ']';
481     sqlite3_snprintf(100,&zBuf[k], encnames[pMem->enc]);
482     k += sqlite3Strlen30(&zBuf[k]);
483     zBuf[k++] = 0;
484   }
485 }
486 #endif
487 
488 #ifdef SQLITE_DEBUG
489 /*
490 ** Print the value of a register for tracing purposes:
491 */
492 static void memTracePrint(Mem *p){
493   if( p->flags & MEM_Undefined ){
494     printf(" undefined");
495   }else if( p->flags & MEM_Null ){
496     printf(p->flags & MEM_Zero ? " NULL-nochng" : " NULL");
497   }else if( (p->flags & (MEM_Int|MEM_Str))==(MEM_Int|MEM_Str) ){
498     printf(" si:%lld", p->u.i);
499   }else if( p->flags & MEM_Int ){
500     printf(" i:%lld", p->u.i);
501 #ifndef SQLITE_OMIT_FLOATING_POINT
502   }else if( p->flags & MEM_Real ){
503     printf(" r:%g", p->u.r);
504 #endif
505   }else if( sqlite3VdbeMemIsRowSet(p) ){
506     printf(" (rowset)");
507   }else{
508     char zBuf[200];
509     sqlite3VdbeMemPrettyPrint(p, zBuf);
510     printf(" %s", zBuf);
511   }
512   if( p->flags & MEM_Subtype ) printf(" subtype=0x%02x", p->eSubtype);
513 }
514 static void registerTrace(int iReg, Mem *p){
515   printf("REG[%d] = ", iReg);
516   memTracePrint(p);
517   printf("\n");
518   sqlite3VdbeCheckMemInvariants(p);
519 }
520 #endif
521 
522 #ifdef SQLITE_DEBUG
523 #  define REGISTER_TRACE(R,M) if(db->flags&SQLITE_VdbeTrace)registerTrace(R,M)
524 #else
525 #  define REGISTER_TRACE(R,M)
526 #endif
527 
528 
529 #ifdef VDBE_PROFILE
530 
531 /*
532 ** hwtime.h contains inline assembler code for implementing
533 ** high-performance timing routines.
534 */
535 #include "hwtime.h"
536 
537 #endif
538 
539 #ifndef NDEBUG
540 /*
541 ** This function is only called from within an assert() expression. It
542 ** checks that the sqlite3.nTransaction variable is correctly set to
543 ** the number of non-transaction savepoints currently in the
544 ** linked list starting at sqlite3.pSavepoint.
545 **
546 ** Usage:
547 **
548 **     assert( checkSavepointCount(db) );
549 */
550 static int checkSavepointCount(sqlite3 *db){
551   int n = 0;
552   Savepoint *p;
553   for(p=db->pSavepoint; p; p=p->pNext) n++;
554   assert( n==(db->nSavepoint + db->isTransactionSavepoint) );
555   return 1;
556 }
557 #endif
558 
559 /*
560 ** Return the register of pOp->p2 after first preparing it to be
561 ** overwritten with an integer value.
562 */
563 static SQLITE_NOINLINE Mem *out2PrereleaseWithClear(Mem *pOut){
564   sqlite3VdbeMemSetNull(pOut);
565   pOut->flags = MEM_Int;
566   return pOut;
567 }
568 static Mem *out2Prerelease(Vdbe *p, VdbeOp *pOp){
569   Mem *pOut;
570   assert( pOp->p2>0 );
571   assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
572   pOut = &p->aMem[pOp->p2];
573   memAboutToChange(p, pOut);
574   if( VdbeMemDynamic(pOut) ){ /*OPTIMIZATION-IF-FALSE*/
575     return out2PrereleaseWithClear(pOut);
576   }else{
577     pOut->flags = MEM_Int;
578     return pOut;
579   }
580 }
581 
582 
583 /*
584 ** Execute as much of a VDBE program as we can.
585 ** This is the core of sqlite3_step().
586 */
587 int sqlite3VdbeExec(
588   Vdbe *p                    /* The VDBE */
589 ){
590   Op *aOp = p->aOp;          /* Copy of p->aOp */
591   Op *pOp = aOp;             /* Current operation */
592 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
593   Op *pOrigOp;               /* Value of pOp at the top of the loop */
594 #endif
595 #ifdef SQLITE_DEBUG
596   int nExtraDelete = 0;      /* Verifies FORDELETE and AUXDELETE flags */
597 #endif
598   int rc = SQLITE_OK;        /* Value to return */
599   sqlite3 *db = p->db;       /* The database */
600   u8 resetSchemaOnFault = 0; /* Reset schema after an error if positive */
601   u8 encoding = ENC(db);     /* The database encoding */
602   int iCompare = 0;          /* Result of last comparison */
603   unsigned nVmStep = 0;      /* Number of virtual machine steps */
604 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
605   unsigned nProgressLimit;   /* Invoke xProgress() when nVmStep reaches this */
606 #endif
607   Mem *aMem = p->aMem;       /* Copy of p->aMem */
608   Mem *pIn1 = 0;             /* 1st input operand */
609   Mem *pIn2 = 0;             /* 2nd input operand */
610   Mem *pIn3 = 0;             /* 3rd input operand */
611   Mem *pOut = 0;             /* Output operand */
612 #ifdef VDBE_PROFILE
613   u64 start;                 /* CPU clock count at start of opcode */
614 #endif
615   /*** INSERT STACK UNION HERE ***/
616 
617   assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
618   sqlite3VdbeEnter(p);
619   if( p->rc==SQLITE_NOMEM ){
620     /* This happens if a malloc() inside a call to sqlite3_column_text() or
621     ** sqlite3_column_text16() failed.  */
622     goto no_mem;
623   }
624   assert( p->rc==SQLITE_OK || (p->rc&0xff)==SQLITE_BUSY );
625   assert( p->bIsReader || p->readOnly!=0 );
626   p->iCurrentTime = 0;
627   assert( p->explain==0 );
628   p->pResultSet = 0;
629   db->busyHandler.nBusy = 0;
630   if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
631   sqlite3VdbeIOTraceSql(p);
632 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
633   if( db->xProgress ){
634     u32 iPrior = p->aCounter[SQLITE_STMTSTATUS_VM_STEP];
635     assert( 0 < db->nProgressOps );
636     nProgressLimit = db->nProgressOps - (iPrior % db->nProgressOps);
637   }else{
638     nProgressLimit = 0xffffffff;
639   }
640 #endif
641 #ifdef SQLITE_DEBUG
642   sqlite3BeginBenignMalloc();
643   if( p->pc==0
644    && (p->db->flags & (SQLITE_VdbeListing|SQLITE_VdbeEQP|SQLITE_VdbeTrace))!=0
645   ){
646     int i;
647     int once = 1;
648     sqlite3VdbePrintSql(p);
649     if( p->db->flags & SQLITE_VdbeListing ){
650       printf("VDBE Program Listing:\n");
651       for(i=0; i<p->nOp; i++){
652         sqlite3VdbePrintOp(stdout, i, &aOp[i]);
653       }
654     }
655     if( p->db->flags & SQLITE_VdbeEQP ){
656       for(i=0; i<p->nOp; i++){
657         if( aOp[i].opcode==OP_Explain ){
658           if( once ) printf("VDBE Query Plan:\n");
659           printf("%s\n", aOp[i].p4.z);
660           once = 0;
661         }
662       }
663     }
664     if( p->db->flags & SQLITE_VdbeTrace )  printf("VDBE Trace:\n");
665   }
666   sqlite3EndBenignMalloc();
667 #endif
668   for(pOp=&aOp[p->pc]; 1; pOp++){
669     /* Errors are detected by individual opcodes, with an immediate
670     ** jumps to abort_due_to_error. */
671     assert( rc==SQLITE_OK );
672 
673     assert( pOp>=aOp && pOp<&aOp[p->nOp]);
674 #ifdef VDBE_PROFILE
675     start = sqlite3NProfileCnt ? sqlite3NProfileCnt : sqlite3Hwtime();
676 #endif
677     nVmStep++;
678 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS
679     if( p->anExec ) p->anExec[(int)(pOp-aOp)]++;
680 #endif
681 
682     /* Only allow tracing if SQLITE_DEBUG is defined.
683     */
684 #ifdef SQLITE_DEBUG
685     if( db->flags & SQLITE_VdbeTrace ){
686       sqlite3VdbePrintOp(stdout, (int)(pOp - aOp), pOp);
687     }
688 #endif
689 
690 
691     /* Check to see if we need to simulate an interrupt.  This only happens
692     ** if we have a special test build.
693     */
694 #ifdef SQLITE_TEST
695     if( sqlite3_interrupt_count>0 ){
696       sqlite3_interrupt_count--;
697       if( sqlite3_interrupt_count==0 ){
698         sqlite3_interrupt(db);
699       }
700     }
701 #endif
702 
703     /* Sanity checking on other operands */
704 #ifdef SQLITE_DEBUG
705     {
706       u8 opProperty = sqlite3OpcodeProperty[pOp->opcode];
707       if( (opProperty & OPFLG_IN1)!=0 ){
708         assert( pOp->p1>0 );
709         assert( pOp->p1<=(p->nMem+1 - p->nCursor) );
710         assert( memIsValid(&aMem[pOp->p1]) );
711         assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p1]) );
712         REGISTER_TRACE(pOp->p1, &aMem[pOp->p1]);
713       }
714       if( (opProperty & OPFLG_IN2)!=0 ){
715         assert( pOp->p2>0 );
716         assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
717         assert( memIsValid(&aMem[pOp->p2]) );
718         assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p2]) );
719         REGISTER_TRACE(pOp->p2, &aMem[pOp->p2]);
720       }
721       if( (opProperty & OPFLG_IN3)!=0 ){
722         assert( pOp->p3>0 );
723         assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
724         assert( memIsValid(&aMem[pOp->p3]) );
725         assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p3]) );
726         REGISTER_TRACE(pOp->p3, &aMem[pOp->p3]);
727       }
728       if( (opProperty & OPFLG_OUT2)!=0 ){
729         assert( pOp->p2>0 );
730         assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
731         memAboutToChange(p, &aMem[pOp->p2]);
732       }
733       if( (opProperty & OPFLG_OUT3)!=0 ){
734         assert( pOp->p3>0 );
735         assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
736         memAboutToChange(p, &aMem[pOp->p3]);
737       }
738     }
739 #endif
740 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
741     pOrigOp = pOp;
742 #endif
743 
744     switch( pOp->opcode ){
745 
746 /*****************************************************************************
747 ** What follows is a massive switch statement where each case implements a
748 ** separate instruction in the virtual machine.  If we follow the usual
749 ** indentation conventions, each case should be indented by 6 spaces.  But
750 ** that is a lot of wasted space on the left margin.  So the code within
751 ** the switch statement will break with convention and be flush-left. Another
752 ** big comment (similar to this one) will mark the point in the code where
753 ** we transition back to normal indentation.
754 **
755 ** The formatting of each case is important.  The makefile for SQLite
756 ** generates two C files "opcodes.h" and "opcodes.c" by scanning this
757 ** file looking for lines that begin with "case OP_".  The opcodes.h files
758 ** will be filled with #defines that give unique integer values to each
759 ** opcode and the opcodes.c file is filled with an array of strings where
760 ** each string is the symbolic name for the corresponding opcode.  If the
761 ** case statement is followed by a comment of the form "/# same as ... #/"
762 ** that comment is used to determine the particular value of the opcode.
763 **
764 ** Other keywords in the comment that follows each case are used to
765 ** construct the OPFLG_INITIALIZER value that initializes opcodeProperty[].
766 ** Keywords include: in1, in2, in3, out2, out3.  See
767 ** the mkopcodeh.awk script for additional information.
768 **
769 ** Documentation about VDBE opcodes is generated by scanning this file
770 ** for lines of that contain "Opcode:".  That line and all subsequent
771 ** comment lines are used in the generation of the opcode.html documentation
772 ** file.
773 **
774 ** SUMMARY:
775 **
776 **     Formatting is important to scripts that scan this file.
777 **     Do not deviate from the formatting style currently in use.
778 **
779 *****************************************************************************/
780 
781 /* Opcode:  Goto * P2 * * *
782 **
783 ** An unconditional jump to address P2.
784 ** The next instruction executed will be
785 ** the one at index P2 from the beginning of
786 ** the program.
787 **
788 ** The P1 parameter is not actually used by this opcode.  However, it
789 ** is sometimes set to 1 instead of 0 as a hint to the command-line shell
790 ** that this Goto is the bottom of a loop and that the lines from P2 down
791 ** to the current line should be indented for EXPLAIN output.
792 */
793 case OP_Goto: {             /* jump */
794 jump_to_p2_and_check_for_interrupt:
795   pOp = &aOp[pOp->p2 - 1];
796 
797   /* Opcodes that are used as the bottom of a loop (OP_Next, OP_Prev,
798   ** OP_VNext, or OP_SorterNext) all jump here upon
799   ** completion.  Check to see if sqlite3_interrupt() has been called
800   ** or if the progress callback needs to be invoked.
801   **
802   ** This code uses unstructured "goto" statements and does not look clean.
803   ** But that is not due to sloppy coding habits. The code is written this
804   ** way for performance, to avoid having to run the interrupt and progress
805   ** checks on every opcode.  This helps sqlite3_step() to run about 1.5%
806   ** faster according to "valgrind --tool=cachegrind" */
807 check_for_interrupt:
808   if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
809 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
810   /* Call the progress callback if it is configured and the required number
811   ** of VDBE ops have been executed (either since this invocation of
812   ** sqlite3VdbeExec() or since last time the progress callback was called).
813   ** If the progress callback returns non-zero, exit the virtual machine with
814   ** a return code SQLITE_ABORT.
815   */
816   if( nVmStep>=nProgressLimit && db->xProgress!=0 ){
817     assert( db->nProgressOps!=0 );
818     nProgressLimit = nVmStep + db->nProgressOps - (nVmStep%db->nProgressOps);
819     if( db->xProgress(db->pProgressArg) ){
820       rc = SQLITE_INTERRUPT;
821       goto abort_due_to_error;
822     }
823   }
824 #endif
825 
826   break;
827 }
828 
829 /* Opcode:  Gosub P1 P2 * * *
830 **
831 ** Write the current address onto register P1
832 ** and then jump to address P2.
833 */
834 case OP_Gosub: {            /* jump */
835   assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
836   pIn1 = &aMem[pOp->p1];
837   assert( VdbeMemDynamic(pIn1)==0 );
838   memAboutToChange(p, pIn1);
839   pIn1->flags = MEM_Int;
840   pIn1->u.i = (int)(pOp-aOp);
841   REGISTER_TRACE(pOp->p1, pIn1);
842 
843   /* Most jump operations do a goto to this spot in order to update
844   ** the pOp pointer. */
845 jump_to_p2:
846   pOp = &aOp[pOp->p2 - 1];
847   break;
848 }
849 
850 /* Opcode:  Return P1 * * * *
851 **
852 ** Jump to the next instruction after the address in register P1.  After
853 ** the jump, register P1 becomes undefined.
854 */
855 case OP_Return: {           /* in1 */
856   pIn1 = &aMem[pOp->p1];
857   assert( pIn1->flags==MEM_Int );
858   pOp = &aOp[pIn1->u.i];
859   pIn1->flags = MEM_Undefined;
860   break;
861 }
862 
863 /* Opcode: InitCoroutine P1 P2 P3 * *
864 **
865 ** Set up register P1 so that it will Yield to the coroutine
866 ** located at address P3.
867 **
868 ** If P2!=0 then the coroutine implementation immediately follows
869 ** this opcode.  So jump over the coroutine implementation to
870 ** address P2.
871 **
872 ** See also: EndCoroutine
873 */
874 case OP_InitCoroutine: {     /* jump */
875   assert( pOp->p1>0 &&  pOp->p1<=(p->nMem+1 - p->nCursor) );
876   assert( pOp->p2>=0 && pOp->p2<p->nOp );
877   assert( pOp->p3>=0 && pOp->p3<p->nOp );
878   pOut = &aMem[pOp->p1];
879   assert( !VdbeMemDynamic(pOut) );
880   pOut->u.i = pOp->p3 - 1;
881   pOut->flags = MEM_Int;
882   if( pOp->p2 ) goto jump_to_p2;
883   break;
884 }
885 
886 /* Opcode:  EndCoroutine P1 * * * *
887 **
888 ** The instruction at the address in register P1 is a Yield.
889 ** Jump to the P2 parameter of that Yield.
890 ** After the jump, register P1 becomes undefined.
891 **
892 ** See also: InitCoroutine
893 */
894 case OP_EndCoroutine: {           /* in1 */
895   VdbeOp *pCaller;
896   pIn1 = &aMem[pOp->p1];
897   assert( pIn1->flags==MEM_Int );
898   assert( pIn1->u.i>=0 && pIn1->u.i<p->nOp );
899   pCaller = &aOp[pIn1->u.i];
900   assert( pCaller->opcode==OP_Yield );
901   assert( pCaller->p2>=0 && pCaller->p2<p->nOp );
902   pOp = &aOp[pCaller->p2 - 1];
903   pIn1->flags = MEM_Undefined;
904   break;
905 }
906 
907 /* Opcode:  Yield P1 P2 * * *
908 **
909 ** Swap the program counter with the value in register P1.  This
910 ** has the effect of yielding to a coroutine.
911 **
912 ** If the coroutine that is launched by this instruction ends with
913 ** Yield or Return then continue to the next instruction.  But if
914 ** the coroutine launched by this instruction ends with
915 ** EndCoroutine, then jump to P2 rather than continuing with the
916 ** next instruction.
917 **
918 ** See also: InitCoroutine
919 */
920 case OP_Yield: {            /* in1, jump */
921   int pcDest;
922   pIn1 = &aMem[pOp->p1];
923   assert( VdbeMemDynamic(pIn1)==0 );
924   pIn1->flags = MEM_Int;
925   pcDest = (int)pIn1->u.i;
926   pIn1->u.i = (int)(pOp - aOp);
927   REGISTER_TRACE(pOp->p1, pIn1);
928   pOp = &aOp[pcDest];
929   break;
930 }
931 
932 /* Opcode:  HaltIfNull  P1 P2 P3 P4 P5
933 ** Synopsis: if r[P3]=null halt
934 **
935 ** Check the value in register P3.  If it is NULL then Halt using
936 ** parameter P1, P2, and P4 as if this were a Halt instruction.  If the
937 ** value in register P3 is not NULL, then this routine is a no-op.
938 ** The P5 parameter should be 1.
939 */
940 case OP_HaltIfNull: {      /* in3 */
941   pIn3 = &aMem[pOp->p3];
942 #ifdef SQLITE_DEBUG
943   if( pOp->p2==OE_Abort ){ sqlite3VdbeAssertAbortable(p); }
944 #endif
945   if( (pIn3->flags & MEM_Null)==0 ) break;
946   /* Fall through into OP_Halt */
947 }
948 
949 /* Opcode:  Halt P1 P2 * P4 P5
950 **
951 ** Exit immediately.  All open cursors, etc are closed
952 ** automatically.
953 **
954 ** P1 is the result code returned by sqlite3_exec(), sqlite3_reset(),
955 ** or sqlite3_finalize().  For a normal halt, this should be SQLITE_OK (0).
956 ** For errors, it can be some other value.  If P1!=0 then P2 will determine
957 ** whether or not to rollback the current transaction.  Do not rollback
958 ** if P2==OE_Fail. Do the rollback if P2==OE_Rollback.  If P2==OE_Abort,
959 ** then back out all changes that have occurred during this execution of the
960 ** VDBE, but do not rollback the transaction.
961 **
962 ** If P4 is not null then it is an error message string.
963 **
964 ** P5 is a value between 0 and 4, inclusive, that modifies the P4 string.
965 **
966 **    0:  (no change)
967 **    1:  NOT NULL contraint failed: P4
968 **    2:  UNIQUE constraint failed: P4
969 **    3:  CHECK constraint failed: P4
970 **    4:  FOREIGN KEY constraint failed: P4
971 **
972 ** If P5 is not zero and P4 is NULL, then everything after the ":" is
973 ** omitted.
974 **
975 ** There is an implied "Halt 0 0 0" instruction inserted at the very end of
976 ** every program.  So a jump past the last instruction of the program
977 ** is the same as executing Halt.
978 */
979 case OP_Halt: {
980   VdbeFrame *pFrame;
981   int pcx;
982 
983   pcx = (int)(pOp - aOp);
984 #ifdef SQLITE_DEBUG
985   if( pOp->p2==OE_Abort ){ sqlite3VdbeAssertAbortable(p); }
986 #endif
987   if( pOp->p1==SQLITE_OK && p->pFrame ){
988     /* Halt the sub-program. Return control to the parent frame. */
989     pFrame = p->pFrame;
990     p->pFrame = pFrame->pParent;
991     p->nFrame--;
992     sqlite3VdbeSetChanges(db, p->nChange);
993     pcx = sqlite3VdbeFrameRestore(pFrame);
994     if( pOp->p2==OE_Ignore ){
995       /* Instruction pcx is the OP_Program that invoked the sub-program
996       ** currently being halted. If the p2 instruction of this OP_Halt
997       ** instruction is set to OE_Ignore, then the sub-program is throwing
998       ** an IGNORE exception. In this case jump to the address specified
999       ** as the p2 of the calling OP_Program.  */
1000       pcx = p->aOp[pcx].p2-1;
1001     }
1002     aOp = p->aOp;
1003     aMem = p->aMem;
1004     pOp = &aOp[pcx];
1005     break;
1006   }
1007   p->rc = pOp->p1;
1008   p->errorAction = (u8)pOp->p2;
1009   p->pc = pcx;
1010   assert( pOp->p5<=4 );
1011   if( p->rc ){
1012     if( pOp->p5 ){
1013       static const char * const azType[] = { "NOT NULL", "UNIQUE", "CHECK",
1014                                              "FOREIGN KEY" };
1015       testcase( pOp->p5==1 );
1016       testcase( pOp->p5==2 );
1017       testcase( pOp->p5==3 );
1018       testcase( pOp->p5==4 );
1019       sqlite3VdbeError(p, "%s constraint failed", azType[pOp->p5-1]);
1020       if( pOp->p4.z ){
1021         p->zErrMsg = sqlite3MPrintf(db, "%z: %s", p->zErrMsg, pOp->p4.z);
1022       }
1023     }else{
1024       sqlite3VdbeError(p, "%s", pOp->p4.z);
1025     }
1026     sqlite3_log(pOp->p1, "abort at %d in [%s]: %s", pcx, p->zSql, p->zErrMsg);
1027   }
1028   rc = sqlite3VdbeHalt(p);
1029   assert( rc==SQLITE_BUSY || rc==SQLITE_OK || rc==SQLITE_ERROR );
1030   if( rc==SQLITE_BUSY ){
1031     p->rc = SQLITE_BUSY;
1032   }else{
1033     assert( rc==SQLITE_OK || (p->rc&0xff)==SQLITE_CONSTRAINT );
1034     assert( rc==SQLITE_OK || db->nDeferredCons>0 || db->nDeferredImmCons>0 );
1035     rc = p->rc ? SQLITE_ERROR : SQLITE_DONE;
1036   }
1037   goto vdbe_return;
1038 }
1039 
1040 /* Opcode: Integer P1 P2 * * *
1041 ** Synopsis: r[P2]=P1
1042 **
1043 ** The 32-bit integer value P1 is written into register P2.
1044 */
1045 case OP_Integer: {         /* out2 */
1046   pOut = out2Prerelease(p, pOp);
1047   pOut->u.i = pOp->p1;
1048   break;
1049 }
1050 
1051 /* Opcode: Int64 * P2 * P4 *
1052 ** Synopsis: r[P2]=P4
1053 **
1054 ** P4 is a pointer to a 64-bit integer value.
1055 ** Write that value into register P2.
1056 */
1057 case OP_Int64: {           /* out2 */
1058   pOut = out2Prerelease(p, pOp);
1059   assert( pOp->p4.pI64!=0 );
1060   pOut->u.i = *pOp->p4.pI64;
1061   break;
1062 }
1063 
1064 #ifndef SQLITE_OMIT_FLOATING_POINT
1065 /* Opcode: Real * P2 * P4 *
1066 ** Synopsis: r[P2]=P4
1067 **
1068 ** P4 is a pointer to a 64-bit floating point value.
1069 ** Write that value into register P2.
1070 */
1071 case OP_Real: {            /* same as TK_FLOAT, out2 */
1072   pOut = out2Prerelease(p, pOp);
1073   pOut->flags = MEM_Real;
1074   assert( !sqlite3IsNaN(*pOp->p4.pReal) );
1075   pOut->u.r = *pOp->p4.pReal;
1076   break;
1077 }
1078 #endif
1079 
1080 /* Opcode: String8 * P2 * P4 *
1081 ** Synopsis: r[P2]='P4'
1082 **
1083 ** P4 points to a nul terminated UTF-8 string. This opcode is transformed
1084 ** into a String opcode before it is executed for the first time.  During
1085 ** this transformation, the length of string P4 is computed and stored
1086 ** as the P1 parameter.
1087 */
1088 case OP_String8: {         /* same as TK_STRING, out2 */
1089   assert( pOp->p4.z!=0 );
1090   pOut = out2Prerelease(p, pOp);
1091   pOp->opcode = OP_String;
1092   pOp->p1 = sqlite3Strlen30(pOp->p4.z);
1093 
1094 #ifndef SQLITE_OMIT_UTF16
1095   if( encoding!=SQLITE_UTF8 ){
1096     rc = sqlite3VdbeMemSetStr(pOut, pOp->p4.z, -1, SQLITE_UTF8, SQLITE_STATIC);
1097     assert( rc==SQLITE_OK || rc==SQLITE_TOOBIG );
1098     if( SQLITE_OK!=sqlite3VdbeChangeEncoding(pOut, encoding) ) goto no_mem;
1099     assert( pOut->szMalloc>0 && pOut->zMalloc==pOut->z );
1100     assert( VdbeMemDynamic(pOut)==0 );
1101     pOut->szMalloc = 0;
1102     pOut->flags |= MEM_Static;
1103     if( pOp->p4type==P4_DYNAMIC ){
1104       sqlite3DbFree(db, pOp->p4.z);
1105     }
1106     pOp->p4type = P4_DYNAMIC;
1107     pOp->p4.z = pOut->z;
1108     pOp->p1 = pOut->n;
1109   }
1110   testcase( rc==SQLITE_TOOBIG );
1111 #endif
1112   if( pOp->p1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
1113     goto too_big;
1114   }
1115   assert( rc==SQLITE_OK );
1116   /* Fall through to the next case, OP_String */
1117 }
1118 
1119 /* Opcode: String P1 P2 P3 P4 P5
1120 ** Synopsis: r[P2]='P4' (len=P1)
1121 **
1122 ** The string value P4 of length P1 (bytes) is stored in register P2.
1123 **
1124 ** If P3 is not zero and the content of register P3 is equal to P5, then
1125 ** the datatype of the register P2 is converted to BLOB.  The content is
1126 ** the same sequence of bytes, it is merely interpreted as a BLOB instead
1127 ** of a string, as if it had been CAST.  In other words:
1128 **
1129 ** if( P3!=0 and reg[P3]==P5 ) reg[P2] := CAST(reg[P2] as BLOB)
1130 */
1131 case OP_String: {          /* out2 */
1132   assert( pOp->p4.z!=0 );
1133   pOut = out2Prerelease(p, pOp);
1134   pOut->flags = MEM_Str|MEM_Static|MEM_Term;
1135   pOut->z = pOp->p4.z;
1136   pOut->n = pOp->p1;
1137   pOut->enc = encoding;
1138   UPDATE_MAX_BLOBSIZE(pOut);
1139 #ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
1140   if( pOp->p3>0 ){
1141     assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
1142     pIn3 = &aMem[pOp->p3];
1143     assert( pIn3->flags & MEM_Int );
1144     if( pIn3->u.i==pOp->p5 ) pOut->flags = MEM_Blob|MEM_Static|MEM_Term;
1145   }
1146 #endif
1147   break;
1148 }
1149 
1150 /* Opcode: Null P1 P2 P3 * *
1151 ** Synopsis: r[P2..P3]=NULL
1152 **
1153 ** Write a NULL into registers P2.  If P3 greater than P2, then also write
1154 ** NULL into register P3 and every register in between P2 and P3.  If P3
1155 ** is less than P2 (typically P3 is zero) then only register P2 is
1156 ** set to NULL.
1157 **
1158 ** If the P1 value is non-zero, then also set the MEM_Cleared flag so that
1159 ** NULL values will not compare equal even if SQLITE_NULLEQ is set on
1160 ** OP_Ne or OP_Eq.
1161 */
1162 case OP_Null: {           /* out2 */
1163   int cnt;
1164   u16 nullFlag;
1165   pOut = out2Prerelease(p, pOp);
1166   cnt = pOp->p3-pOp->p2;
1167   assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
1168   pOut->flags = nullFlag = pOp->p1 ? (MEM_Null|MEM_Cleared) : MEM_Null;
1169   pOut->n = 0;
1170 #ifdef SQLITE_DEBUG
1171   pOut->uTemp = 0;
1172 #endif
1173   while( cnt>0 ){
1174     pOut++;
1175     memAboutToChange(p, pOut);
1176     sqlite3VdbeMemSetNull(pOut);
1177     pOut->flags = nullFlag;
1178     pOut->n = 0;
1179     cnt--;
1180   }
1181   break;
1182 }
1183 
1184 /* Opcode: SoftNull P1 * * * *
1185 ** Synopsis: r[P1]=NULL
1186 **
1187 ** Set register P1 to have the value NULL as seen by the OP_MakeRecord
1188 ** instruction, but do not free any string or blob memory associated with
1189 ** the register, so that if the value was a string or blob that was
1190 ** previously copied using OP_SCopy, the copies will continue to be valid.
1191 */
1192 case OP_SoftNull: {
1193   assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
1194   pOut = &aMem[pOp->p1];
1195   pOut->flags = (pOut->flags&~(MEM_Undefined|MEM_AffMask))|MEM_Null;
1196   break;
1197 }
1198 
1199 /* Opcode: Blob P1 P2 * P4 *
1200 ** Synopsis: r[P2]=P4 (len=P1)
1201 **
1202 ** P4 points to a blob of data P1 bytes long.  Store this
1203 ** blob in register P2.
1204 */
1205 case OP_Blob: {                /* out2 */
1206   assert( pOp->p1 <= SQLITE_MAX_LENGTH );
1207   pOut = out2Prerelease(p, pOp);
1208   sqlite3VdbeMemSetStr(pOut, pOp->p4.z, pOp->p1, 0, 0);
1209   pOut->enc = encoding;
1210   UPDATE_MAX_BLOBSIZE(pOut);
1211   break;
1212 }
1213 
1214 /* Opcode: Variable P1 P2 * P4 *
1215 ** Synopsis: r[P2]=parameter(P1,P4)
1216 **
1217 ** Transfer the values of bound parameter P1 into register P2
1218 **
1219 ** If the parameter is named, then its name appears in P4.
1220 ** The P4 value is used by sqlite3_bind_parameter_name().
1221 */
1222 case OP_Variable: {            /* out2 */
1223   Mem *pVar;       /* Value being transferred */
1224 
1225   assert( pOp->p1>0 && pOp->p1<=p->nVar );
1226   assert( pOp->p4.z==0 || pOp->p4.z==sqlite3VListNumToName(p->pVList,pOp->p1) );
1227   pVar = &p->aVar[pOp->p1 - 1];
1228   if( sqlite3VdbeMemTooBig(pVar) ){
1229     goto too_big;
1230   }
1231   pOut = &aMem[pOp->p2];
1232   sqlite3VdbeMemShallowCopy(pOut, pVar, MEM_Static);
1233   UPDATE_MAX_BLOBSIZE(pOut);
1234   break;
1235 }
1236 
1237 /* Opcode: Move P1 P2 P3 * *
1238 ** Synopsis: r[P2@P3]=r[P1@P3]
1239 **
1240 ** Move the P3 values in register P1..P1+P3-1 over into
1241 ** registers P2..P2+P3-1.  Registers P1..P1+P3-1 are
1242 ** left holding a NULL.  It is an error for register ranges
1243 ** P1..P1+P3-1 and P2..P2+P3-1 to overlap.  It is an error
1244 ** for P3 to be less than 1.
1245 */
1246 case OP_Move: {
1247   int n;           /* Number of registers left to copy */
1248   int p1;          /* Register to copy from */
1249   int p2;          /* Register to copy to */
1250 
1251   n = pOp->p3;
1252   p1 = pOp->p1;
1253   p2 = pOp->p2;
1254   assert( n>0 && p1>0 && p2>0 );
1255   assert( p1+n<=p2 || p2+n<=p1 );
1256 
1257   pIn1 = &aMem[p1];
1258   pOut = &aMem[p2];
1259   do{
1260     assert( pOut<=&aMem[(p->nMem+1 - p->nCursor)] );
1261     assert( pIn1<=&aMem[(p->nMem+1 - p->nCursor)] );
1262     assert( memIsValid(pIn1) );
1263     memAboutToChange(p, pOut);
1264     sqlite3VdbeMemMove(pOut, pIn1);
1265 #ifdef SQLITE_DEBUG
1266     if( pOut->pScopyFrom>=&aMem[p1] && pOut->pScopyFrom<pOut ){
1267       pOut->pScopyFrom += pOp->p2 - p1;
1268     }
1269 #endif
1270     Deephemeralize(pOut);
1271     REGISTER_TRACE(p2++, pOut);
1272     pIn1++;
1273     pOut++;
1274   }while( --n );
1275   break;
1276 }
1277 
1278 /* Opcode: Copy P1 P2 P3 * *
1279 ** Synopsis: r[P2@P3+1]=r[P1@P3+1]
1280 **
1281 ** Make a copy of registers P1..P1+P3 into registers P2..P2+P3.
1282 **
1283 ** This instruction makes a deep copy of the value.  A duplicate
1284 ** is made of any string or blob constant.  See also OP_SCopy.
1285 */
1286 case OP_Copy: {
1287   int n;
1288 
1289   n = pOp->p3;
1290   pIn1 = &aMem[pOp->p1];
1291   pOut = &aMem[pOp->p2];
1292   assert( pOut!=pIn1 );
1293   while( 1 ){
1294     memAboutToChange(p, pOut);
1295     sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
1296     Deephemeralize(pOut);
1297 #ifdef SQLITE_DEBUG
1298     pOut->pScopyFrom = 0;
1299 #endif
1300     REGISTER_TRACE(pOp->p2+pOp->p3-n, pOut);
1301     if( (n--)==0 ) break;
1302     pOut++;
1303     pIn1++;
1304   }
1305   break;
1306 }
1307 
1308 /* Opcode: SCopy P1 P2 * * *
1309 ** Synopsis: r[P2]=r[P1]
1310 **
1311 ** Make a shallow copy of register P1 into register P2.
1312 **
1313 ** This instruction makes a shallow copy of the value.  If the value
1314 ** is a string or blob, then the copy is only a pointer to the
1315 ** original and hence if the original changes so will the copy.
1316 ** Worse, if the original is deallocated, the copy becomes invalid.
1317 ** Thus the program must guarantee that the original will not change
1318 ** during the lifetime of the copy.  Use OP_Copy to make a complete
1319 ** copy.
1320 */
1321 case OP_SCopy: {            /* out2 */
1322   pIn1 = &aMem[pOp->p1];
1323   pOut = &aMem[pOp->p2];
1324   assert( pOut!=pIn1 );
1325   sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
1326 #ifdef SQLITE_DEBUG
1327   pOut->pScopyFrom = pIn1;
1328   pOut->mScopyFlags = pIn1->flags;
1329 #endif
1330   break;
1331 }
1332 
1333 /* Opcode: IntCopy P1 P2 * * *
1334 ** Synopsis: r[P2]=r[P1]
1335 **
1336 ** Transfer the integer value held in register P1 into register P2.
1337 **
1338 ** This is an optimized version of SCopy that works only for integer
1339 ** values.
1340 */
1341 case OP_IntCopy: {            /* out2 */
1342   pIn1 = &aMem[pOp->p1];
1343   assert( (pIn1->flags & MEM_Int)!=0 );
1344   pOut = &aMem[pOp->p2];
1345   sqlite3VdbeMemSetInt64(pOut, pIn1->u.i);
1346   break;
1347 }
1348 
1349 /* Opcode: ResultRow P1 P2 * * *
1350 ** Synopsis: output=r[P1@P2]
1351 **
1352 ** The registers P1 through P1+P2-1 contain a single row of
1353 ** results. This opcode causes the sqlite3_step() call to terminate
1354 ** with an SQLITE_ROW return code and it sets up the sqlite3_stmt
1355 ** structure to provide access to the r(P1)..r(P1+P2-1) values as
1356 ** the result row.
1357 */
1358 case OP_ResultRow: {
1359   Mem *pMem;
1360   int i;
1361   assert( p->nResColumn==pOp->p2 );
1362   assert( pOp->p1>0 );
1363   assert( pOp->p1+pOp->p2<=(p->nMem+1 - p->nCursor)+1 );
1364 
1365 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1366   /* Run the progress counter just before returning.
1367   */
1368   if( db->xProgress!=0
1369    && nVmStep>=nProgressLimit
1370    && db->xProgress(db->pProgressArg)!=0
1371   ){
1372     rc = SQLITE_INTERRUPT;
1373     goto abort_due_to_error;
1374   }
1375 #endif
1376 
1377   /* If this statement has violated immediate foreign key constraints, do
1378   ** not return the number of rows modified. And do not RELEASE the statement
1379   ** transaction. It needs to be rolled back.  */
1380   if( SQLITE_OK!=(rc = sqlite3VdbeCheckFk(p, 0)) ){
1381     assert( db->flags&SQLITE_CountRows );
1382     assert( p->usesStmtJournal );
1383     goto abort_due_to_error;
1384   }
1385 
1386   /* If the SQLITE_CountRows flag is set in sqlite3.flags mask, then
1387   ** DML statements invoke this opcode to return the number of rows
1388   ** modified to the user. This is the only way that a VM that
1389   ** opens a statement transaction may invoke this opcode.
1390   **
1391   ** In case this is such a statement, close any statement transaction
1392   ** opened by this VM before returning control to the user. This is to
1393   ** ensure that statement-transactions are always nested, not overlapping.
1394   ** If the open statement-transaction is not closed here, then the user
1395   ** may step another VM that opens its own statement transaction. This
1396   ** may lead to overlapping statement transactions.
1397   **
1398   ** The statement transaction is never a top-level transaction.  Hence
1399   ** the RELEASE call below can never fail.
1400   */
1401   assert( p->iStatement==0 || db->flags&SQLITE_CountRows );
1402   rc = sqlite3VdbeCloseStatement(p, SAVEPOINT_RELEASE);
1403   assert( rc==SQLITE_OK );
1404 
1405   /* Invalidate all ephemeral cursor row caches */
1406   p->cacheCtr = (p->cacheCtr + 2)|1;
1407 
1408   /* Make sure the results of the current row are \000 terminated
1409   ** and have an assigned type.  The results are de-ephemeralized as
1410   ** a side effect.
1411   */
1412   pMem = p->pResultSet = &aMem[pOp->p1];
1413   for(i=0; i<pOp->p2; i++){
1414     assert( memIsValid(&pMem[i]) );
1415     Deephemeralize(&pMem[i]);
1416     assert( (pMem[i].flags & MEM_Ephem)==0
1417             || (pMem[i].flags & (MEM_Str|MEM_Blob))==0 );
1418     sqlite3VdbeMemNulTerminate(&pMem[i]);
1419     REGISTER_TRACE(pOp->p1+i, &pMem[i]);
1420   }
1421   if( db->mallocFailed ) goto no_mem;
1422 
1423   if( db->mTrace & SQLITE_TRACE_ROW ){
1424     db->xTrace(SQLITE_TRACE_ROW, db->pTraceArg, p, 0);
1425   }
1426 
1427   /* Return SQLITE_ROW
1428   */
1429   p->pc = (int)(pOp - aOp) + 1;
1430   rc = SQLITE_ROW;
1431   goto vdbe_return;
1432 }
1433 
1434 /* Opcode: Concat P1 P2 P3 * *
1435 ** Synopsis: r[P3]=r[P2]+r[P1]
1436 **
1437 ** Add the text in register P1 onto the end of the text in
1438 ** register P2 and store the result in register P3.
1439 ** If either the P1 or P2 text are NULL then store NULL in P3.
1440 **
1441 **   P3 = P2 || P1
1442 **
1443 ** It is illegal for P1 and P3 to be the same register. Sometimes,
1444 ** if P3 is the same register as P2, the implementation is able
1445 ** to avoid a memcpy().
1446 */
1447 case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
1448   i64 nByte;
1449 
1450   pIn1 = &aMem[pOp->p1];
1451   pIn2 = &aMem[pOp->p2];
1452   pOut = &aMem[pOp->p3];
1453   assert( pIn1!=pOut );
1454   if( (pIn1->flags | pIn2->flags) & MEM_Null ){
1455     sqlite3VdbeMemSetNull(pOut);
1456     break;
1457   }
1458   if( ExpandBlob(pIn1) || ExpandBlob(pIn2) ) goto no_mem;
1459   Stringify(pIn1, encoding);
1460   Stringify(pIn2, encoding);
1461   nByte = pIn1->n + pIn2->n;
1462   if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
1463     goto too_big;
1464   }
1465   if( sqlite3VdbeMemGrow(pOut, (int)nByte+2, pOut==pIn2) ){
1466     goto no_mem;
1467   }
1468   MemSetTypeFlag(pOut, MEM_Str);
1469   if( pOut!=pIn2 ){
1470     memcpy(pOut->z, pIn2->z, pIn2->n);
1471   }
1472   memcpy(&pOut->z[pIn2->n], pIn1->z, pIn1->n);
1473   pOut->z[nByte]=0;
1474   pOut->z[nByte+1] = 0;
1475   pOut->flags |= MEM_Term;
1476   pOut->n = (int)nByte;
1477   pOut->enc = encoding;
1478   UPDATE_MAX_BLOBSIZE(pOut);
1479   break;
1480 }
1481 
1482 /* Opcode: Add P1 P2 P3 * *
1483 ** Synopsis: r[P3]=r[P1]+r[P2]
1484 **
1485 ** Add the value in register P1 to the value in register P2
1486 ** and store the result in register P3.
1487 ** If either input is NULL, the result is NULL.
1488 */
1489 /* Opcode: Multiply P1 P2 P3 * *
1490 ** Synopsis: r[P3]=r[P1]*r[P2]
1491 **
1492 **
1493 ** Multiply the value in register P1 by the value in register P2
1494 ** and store the result in register P3.
1495 ** If either input is NULL, the result is NULL.
1496 */
1497 /* Opcode: Subtract P1 P2 P3 * *
1498 ** Synopsis: r[P3]=r[P2]-r[P1]
1499 **
1500 ** Subtract the value in register P1 from the value in register P2
1501 ** and store the result in register P3.
1502 ** If either input is NULL, the result is NULL.
1503 */
1504 /* Opcode: Divide P1 P2 P3 * *
1505 ** Synopsis: r[P3]=r[P2]/r[P1]
1506 **
1507 ** Divide the value in register P1 by the value in register P2
1508 ** and store the result in register P3 (P3=P2/P1). If the value in
1509 ** register P1 is zero, then the result is NULL. If either input is
1510 ** NULL, the result is NULL.
1511 */
1512 /* Opcode: Remainder P1 P2 P3 * *
1513 ** Synopsis: r[P3]=r[P2]%r[P1]
1514 **
1515 ** Compute the remainder after integer register P2 is divided by
1516 ** register P1 and store the result in register P3.
1517 ** If the value in register P1 is zero the result is NULL.
1518 ** If either operand is NULL, the result is NULL.
1519 */
1520 case OP_Add:                   /* same as TK_PLUS, in1, in2, out3 */
1521 case OP_Subtract:              /* same as TK_MINUS, in1, in2, out3 */
1522 case OP_Multiply:              /* same as TK_STAR, in1, in2, out3 */
1523 case OP_Divide:                /* same as TK_SLASH, in1, in2, out3 */
1524 case OP_Remainder: {           /* same as TK_REM, in1, in2, out3 */
1525   char bIntint;   /* Started out as two integer operands */
1526   u16 flags;      /* Combined MEM_* flags from both inputs */
1527   u16 type1;      /* Numeric type of left operand */
1528   u16 type2;      /* Numeric type of right operand */
1529   i64 iA;         /* Integer value of left operand */
1530   i64 iB;         /* Integer value of right operand */
1531   double rA;      /* Real value of left operand */
1532   double rB;      /* Real value of right operand */
1533 
1534   pIn1 = &aMem[pOp->p1];
1535   type1 = numericType(pIn1);
1536   pIn2 = &aMem[pOp->p2];
1537   type2 = numericType(pIn2);
1538   pOut = &aMem[pOp->p3];
1539   flags = pIn1->flags | pIn2->flags;
1540   if( (type1 & type2 & MEM_Int)!=0 ){
1541     iA = pIn1->u.i;
1542     iB = pIn2->u.i;
1543     bIntint = 1;
1544     switch( pOp->opcode ){
1545       case OP_Add:       if( sqlite3AddInt64(&iB,iA) ) goto fp_math;  break;
1546       case OP_Subtract:  if( sqlite3SubInt64(&iB,iA) ) goto fp_math;  break;
1547       case OP_Multiply:  if( sqlite3MulInt64(&iB,iA) ) goto fp_math;  break;
1548       case OP_Divide: {
1549         if( iA==0 ) goto arithmetic_result_is_null;
1550         if( iA==-1 && iB==SMALLEST_INT64 ) goto fp_math;
1551         iB /= iA;
1552         break;
1553       }
1554       default: {
1555         if( iA==0 ) goto arithmetic_result_is_null;
1556         if( iA==-1 ) iA = 1;
1557         iB %= iA;
1558         break;
1559       }
1560     }
1561     pOut->u.i = iB;
1562     MemSetTypeFlag(pOut, MEM_Int);
1563   }else if( (flags & MEM_Null)!=0 ){
1564     goto arithmetic_result_is_null;
1565   }else{
1566     bIntint = 0;
1567 fp_math:
1568     rA = sqlite3VdbeRealValue(pIn1);
1569     rB = sqlite3VdbeRealValue(pIn2);
1570     switch( pOp->opcode ){
1571       case OP_Add:         rB += rA;       break;
1572       case OP_Subtract:    rB -= rA;       break;
1573       case OP_Multiply:    rB *= rA;       break;
1574       case OP_Divide: {
1575         /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
1576         if( rA==(double)0 ) goto arithmetic_result_is_null;
1577         rB /= rA;
1578         break;
1579       }
1580       default: {
1581         iA = (i64)rA;
1582         iB = (i64)rB;
1583         if( iA==0 ) goto arithmetic_result_is_null;
1584         if( iA==-1 ) iA = 1;
1585         rB = (double)(iB % iA);
1586         break;
1587       }
1588     }
1589 #ifdef SQLITE_OMIT_FLOATING_POINT
1590     pOut->u.i = rB;
1591     MemSetTypeFlag(pOut, MEM_Int);
1592 #else
1593     if( sqlite3IsNaN(rB) ){
1594       goto arithmetic_result_is_null;
1595     }
1596     pOut->u.r = rB;
1597     MemSetTypeFlag(pOut, MEM_Real);
1598     if( ((type1|type2)&MEM_Real)==0 && !bIntint ){
1599       sqlite3VdbeIntegerAffinity(pOut);
1600     }
1601 #endif
1602   }
1603   break;
1604 
1605 arithmetic_result_is_null:
1606   sqlite3VdbeMemSetNull(pOut);
1607   break;
1608 }
1609 
1610 /* Opcode: CollSeq P1 * * P4
1611 **
1612 ** P4 is a pointer to a CollSeq object. If the next call to a user function
1613 ** or aggregate calls sqlite3GetFuncCollSeq(), this collation sequence will
1614 ** be returned. This is used by the built-in min(), max() and nullif()
1615 ** functions.
1616 **
1617 ** If P1 is not zero, then it is a register that a subsequent min() or
1618 ** max() aggregate will set to 1 if the current row is not the minimum or
1619 ** maximum.  The P1 register is initialized to 0 by this instruction.
1620 **
1621 ** The interface used by the implementation of the aforementioned functions
1622 ** to retrieve the collation sequence set by this opcode is not available
1623 ** publicly.  Only built-in functions have access to this feature.
1624 */
1625 case OP_CollSeq: {
1626   assert( pOp->p4type==P4_COLLSEQ );
1627   if( pOp->p1 ){
1628     sqlite3VdbeMemSetInt64(&aMem[pOp->p1], 0);
1629   }
1630   break;
1631 }
1632 
1633 /* Opcode: BitAnd P1 P2 P3 * *
1634 ** Synopsis: r[P3]=r[P1]&r[P2]
1635 **
1636 ** Take the bit-wise AND of the values in register P1 and P2 and
1637 ** store the result in register P3.
1638 ** If either input is NULL, the result is NULL.
1639 */
1640 /* Opcode: BitOr P1 P2 P3 * *
1641 ** Synopsis: r[P3]=r[P1]|r[P2]
1642 **
1643 ** Take the bit-wise OR of the values in register P1 and P2 and
1644 ** store the result in register P3.
1645 ** If either input is NULL, the result is NULL.
1646 */
1647 /* Opcode: ShiftLeft P1 P2 P3 * *
1648 ** Synopsis: r[P3]=r[P2]<<r[P1]
1649 **
1650 ** Shift the integer value in register P2 to the left by the
1651 ** number of bits specified by the integer in register P1.
1652 ** Store the result in register P3.
1653 ** If either input is NULL, the result is NULL.
1654 */
1655 /* Opcode: ShiftRight P1 P2 P3 * *
1656 ** Synopsis: r[P3]=r[P2]>>r[P1]
1657 **
1658 ** Shift the integer value in register P2 to the right by the
1659 ** number of bits specified by the integer in register P1.
1660 ** Store the result in register P3.
1661 ** If either input is NULL, the result is NULL.
1662 */
1663 case OP_BitAnd:                 /* same as TK_BITAND, in1, in2, out3 */
1664 case OP_BitOr:                  /* same as TK_BITOR, in1, in2, out3 */
1665 case OP_ShiftLeft:              /* same as TK_LSHIFT, in1, in2, out3 */
1666 case OP_ShiftRight: {           /* same as TK_RSHIFT, in1, in2, out3 */
1667   i64 iA;
1668   u64 uA;
1669   i64 iB;
1670   u8 op;
1671 
1672   pIn1 = &aMem[pOp->p1];
1673   pIn2 = &aMem[pOp->p2];
1674   pOut = &aMem[pOp->p3];
1675   if( (pIn1->flags | pIn2->flags) & MEM_Null ){
1676     sqlite3VdbeMemSetNull(pOut);
1677     break;
1678   }
1679   iA = sqlite3VdbeIntValue(pIn2);
1680   iB = sqlite3VdbeIntValue(pIn1);
1681   op = pOp->opcode;
1682   if( op==OP_BitAnd ){
1683     iA &= iB;
1684   }else if( op==OP_BitOr ){
1685     iA |= iB;
1686   }else if( iB!=0 ){
1687     assert( op==OP_ShiftRight || op==OP_ShiftLeft );
1688 
1689     /* If shifting by a negative amount, shift in the other direction */
1690     if( iB<0 ){
1691       assert( OP_ShiftRight==OP_ShiftLeft+1 );
1692       op = 2*OP_ShiftLeft + 1 - op;
1693       iB = iB>(-64) ? -iB : 64;
1694     }
1695 
1696     if( iB>=64 ){
1697       iA = (iA>=0 || op==OP_ShiftLeft) ? 0 : -1;
1698     }else{
1699       memcpy(&uA, &iA, sizeof(uA));
1700       if( op==OP_ShiftLeft ){
1701         uA <<= iB;
1702       }else{
1703         uA >>= iB;
1704         /* Sign-extend on a right shift of a negative number */
1705         if( iA<0 ) uA |= ((((u64)0xffffffff)<<32)|0xffffffff) << (64-iB);
1706       }
1707       memcpy(&iA, &uA, sizeof(iA));
1708     }
1709   }
1710   pOut->u.i = iA;
1711   MemSetTypeFlag(pOut, MEM_Int);
1712   break;
1713 }
1714 
1715 /* Opcode: AddImm  P1 P2 * * *
1716 ** Synopsis: r[P1]=r[P1]+P2
1717 **
1718 ** Add the constant P2 to the value in register P1.
1719 ** The result is always an integer.
1720 **
1721 ** To force any register to be an integer, just add 0.
1722 */
1723 case OP_AddImm: {            /* in1 */
1724   pIn1 = &aMem[pOp->p1];
1725   memAboutToChange(p, pIn1);
1726   sqlite3VdbeMemIntegerify(pIn1);
1727   pIn1->u.i += pOp->p2;
1728   break;
1729 }
1730 
1731 /* Opcode: MustBeInt P1 P2 * * *
1732 **
1733 ** Force the value in register P1 to be an integer.  If the value
1734 ** in P1 is not an integer and cannot be converted into an integer
1735 ** without data loss, then jump immediately to P2, or if P2==0
1736 ** raise an SQLITE_MISMATCH exception.
1737 */
1738 case OP_MustBeInt: {            /* jump, in1 */
1739   pIn1 = &aMem[pOp->p1];
1740   if( (pIn1->flags & MEM_Int)==0 ){
1741     applyAffinity(pIn1, SQLITE_AFF_NUMERIC, encoding);
1742     VdbeBranchTaken((pIn1->flags&MEM_Int)==0, 2);
1743     if( (pIn1->flags & MEM_Int)==0 ){
1744       if( pOp->p2==0 ){
1745         rc = SQLITE_MISMATCH;
1746         goto abort_due_to_error;
1747       }else{
1748         goto jump_to_p2;
1749       }
1750     }
1751   }
1752   MemSetTypeFlag(pIn1, MEM_Int);
1753   break;
1754 }
1755 
1756 #ifndef SQLITE_OMIT_FLOATING_POINT
1757 /* Opcode: RealAffinity P1 * * * *
1758 **
1759 ** If register P1 holds an integer convert it to a real value.
1760 **
1761 ** This opcode is used when extracting information from a column that
1762 ** has REAL affinity.  Such column values may still be stored as
1763 ** integers, for space efficiency, but after extraction we want them
1764 ** to have only a real value.
1765 */
1766 case OP_RealAffinity: {                  /* in1 */
1767   pIn1 = &aMem[pOp->p1];
1768   if( pIn1->flags & MEM_Int ){
1769     sqlite3VdbeMemRealify(pIn1);
1770   }
1771   break;
1772 }
1773 #endif
1774 
1775 #ifndef SQLITE_OMIT_CAST
1776 /* Opcode: Cast P1 P2 * * *
1777 ** Synopsis: affinity(r[P1])
1778 **
1779 ** Force the value in register P1 to be the type defined by P2.
1780 **
1781 ** <ul>
1782 ** <li> P2=='A' &rarr; BLOB
1783 ** <li> P2=='B' &rarr; TEXT
1784 ** <li> P2=='C' &rarr; NUMERIC
1785 ** <li> P2=='D' &rarr; INTEGER
1786 ** <li> P2=='E' &rarr; REAL
1787 ** </ul>
1788 **
1789 ** A NULL value is not changed by this routine.  It remains NULL.
1790 */
1791 case OP_Cast: {                  /* in1 */
1792   assert( pOp->p2>=SQLITE_AFF_BLOB && pOp->p2<=SQLITE_AFF_REAL );
1793   testcase( pOp->p2==SQLITE_AFF_TEXT );
1794   testcase( pOp->p2==SQLITE_AFF_BLOB );
1795   testcase( pOp->p2==SQLITE_AFF_NUMERIC );
1796   testcase( pOp->p2==SQLITE_AFF_INTEGER );
1797   testcase( pOp->p2==SQLITE_AFF_REAL );
1798   pIn1 = &aMem[pOp->p1];
1799   memAboutToChange(p, pIn1);
1800   rc = ExpandBlob(pIn1);
1801   sqlite3VdbeMemCast(pIn1, pOp->p2, encoding);
1802   UPDATE_MAX_BLOBSIZE(pIn1);
1803   if( rc ) goto abort_due_to_error;
1804   break;
1805 }
1806 #endif /* SQLITE_OMIT_CAST */
1807 
1808 /* Opcode: Eq P1 P2 P3 P4 P5
1809 ** Synopsis: IF r[P3]==r[P1]
1810 **
1811 ** Compare the values in register P1 and P3.  If reg(P3)==reg(P1) then
1812 ** jump to address P2.  Or if the SQLITE_STOREP2 flag is set in P5, then
1813 ** store the result of comparison in register P2.
1814 **
1815 ** The SQLITE_AFF_MASK portion of P5 must be an affinity character -
1816 ** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made
1817 ** to coerce both inputs according to this affinity before the
1818 ** comparison is made. If the SQLITE_AFF_MASK is 0x00, then numeric
1819 ** affinity is used. Note that the affinity conversions are stored
1820 ** back into the input registers P1 and P3.  So this opcode can cause
1821 ** persistent changes to registers P1 and P3.
1822 **
1823 ** Once any conversions have taken place, and neither value is NULL,
1824 ** the values are compared. If both values are blobs then memcmp() is
1825 ** used to determine the results of the comparison.  If both values
1826 ** are text, then the appropriate collating function specified in
1827 ** P4 is used to do the comparison.  If P4 is not specified then
1828 ** memcmp() is used to compare text string.  If both values are
1829 ** numeric, then a numeric comparison is used. If the two values
1830 ** are of different types, then numbers are considered less than
1831 ** strings and strings are considered less than blobs.
1832 **
1833 ** If SQLITE_NULLEQ is set in P5 then the result of comparison is always either
1834 ** true or false and is never NULL.  If both operands are NULL then the result
1835 ** of comparison is true.  If either operand is NULL then the result is false.
1836 ** If neither operand is NULL the result is the same as it would be if
1837 ** the SQLITE_NULLEQ flag were omitted from P5.
1838 **
1839 ** If both SQLITE_STOREP2 and SQLITE_KEEPNULL flags are set then the
1840 ** content of r[P2] is only changed if the new value is NULL or 0 (false).
1841 ** In other words, a prior r[P2] value will not be overwritten by 1 (true).
1842 */
1843 /* Opcode: Ne P1 P2 P3 P4 P5
1844 ** Synopsis: IF r[P3]!=r[P1]
1845 **
1846 ** This works just like the Eq opcode except that the jump is taken if
1847 ** the operands in registers P1 and P3 are not equal.  See the Eq opcode for
1848 ** additional information.
1849 **
1850 ** If both SQLITE_STOREP2 and SQLITE_KEEPNULL flags are set then the
1851 ** content of r[P2] is only changed if the new value is NULL or 1 (true).
1852 ** In other words, a prior r[P2] value will not be overwritten by 0 (false).
1853 */
1854 /* Opcode: Lt P1 P2 P3 P4 P5
1855 ** Synopsis: IF r[P3]<r[P1]
1856 **
1857 ** Compare the values in register P1 and P3.  If reg(P3)<reg(P1) then
1858 ** jump to address P2.  Or if the SQLITE_STOREP2 flag is set in P5 store
1859 ** the result of comparison (0 or 1 or NULL) into register P2.
1860 **
1861 ** If the SQLITE_JUMPIFNULL bit of P5 is set and either reg(P1) or
1862 ** reg(P3) is NULL then the take the jump.  If the SQLITE_JUMPIFNULL
1863 ** bit is clear then fall through if either operand is NULL.
1864 **
1865 ** The SQLITE_AFF_MASK portion of P5 must be an affinity character -
1866 ** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made
1867 ** to coerce both inputs according to this affinity before the
1868 ** comparison is made. If the SQLITE_AFF_MASK is 0x00, then numeric
1869 ** affinity is used. Note that the affinity conversions are stored
1870 ** back into the input registers P1 and P3.  So this opcode can cause
1871 ** persistent changes to registers P1 and P3.
1872 **
1873 ** Once any conversions have taken place, and neither value is NULL,
1874 ** the values are compared. If both values are blobs then memcmp() is
1875 ** used to determine the results of the comparison.  If both values
1876 ** are text, then the appropriate collating function specified in
1877 ** P4 is  used to do the comparison.  If P4 is not specified then
1878 ** memcmp() is used to compare text string.  If both values are
1879 ** numeric, then a numeric comparison is used. If the two values
1880 ** are of different types, then numbers are considered less than
1881 ** strings and strings are considered less than blobs.
1882 */
1883 /* Opcode: Le P1 P2 P3 P4 P5
1884 ** Synopsis: IF r[P3]<=r[P1]
1885 **
1886 ** This works just like the Lt opcode except that the jump is taken if
1887 ** the content of register P3 is less than or equal to the content of
1888 ** register P1.  See the Lt opcode for additional information.
1889 */
1890 /* Opcode: Gt P1 P2 P3 P4 P5
1891 ** Synopsis: IF r[P3]>r[P1]
1892 **
1893 ** This works just like the Lt opcode except that the jump is taken if
1894 ** the content of register P3 is greater than the content of
1895 ** register P1.  See the Lt opcode for additional information.
1896 */
1897 /* Opcode: Ge P1 P2 P3 P4 P5
1898 ** Synopsis: IF r[P3]>=r[P1]
1899 **
1900 ** This works just like the Lt opcode except that the jump is taken if
1901 ** the content of register P3 is greater than or equal to the content of
1902 ** register P1.  See the Lt opcode for additional information.
1903 */
1904 case OP_Eq:               /* same as TK_EQ, jump, in1, in3 */
1905 case OP_Ne:               /* same as TK_NE, jump, in1, in3 */
1906 case OP_Lt:               /* same as TK_LT, jump, in1, in3 */
1907 case OP_Le:               /* same as TK_LE, jump, in1, in3 */
1908 case OP_Gt:               /* same as TK_GT, jump, in1, in3 */
1909 case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
1910   int res, res2;      /* Result of the comparison of pIn1 against pIn3 */
1911   char affinity;      /* Affinity to use for comparison */
1912   u16 flags1;         /* Copy of initial value of pIn1->flags */
1913   u16 flags3;         /* Copy of initial value of pIn3->flags */
1914 
1915   pIn1 = &aMem[pOp->p1];
1916   pIn3 = &aMem[pOp->p3];
1917   flags1 = pIn1->flags;
1918   flags3 = pIn3->flags;
1919   if( (flags1 | flags3)&MEM_Null ){
1920     /* One or both operands are NULL */
1921     if( pOp->p5 & SQLITE_NULLEQ ){
1922       /* If SQLITE_NULLEQ is set (which will only happen if the operator is
1923       ** OP_Eq or OP_Ne) then take the jump or not depending on whether
1924       ** or not both operands are null.
1925       */
1926       assert( pOp->opcode==OP_Eq || pOp->opcode==OP_Ne );
1927       assert( (flags1 & MEM_Cleared)==0 );
1928       assert( (pOp->p5 & SQLITE_JUMPIFNULL)==0 );
1929       if( (flags1&flags3&MEM_Null)!=0
1930        && (flags3&MEM_Cleared)==0
1931       ){
1932         res = 0;  /* Operands are equal */
1933       }else{
1934         res = 1;  /* Operands are not equal */
1935       }
1936     }else{
1937       /* SQLITE_NULLEQ is clear and at least one operand is NULL,
1938       ** then the result is always NULL.
1939       ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
1940       */
1941       if( pOp->p5 & SQLITE_STOREP2 ){
1942         pOut = &aMem[pOp->p2];
1943         iCompare = 1;    /* Operands are not equal */
1944         memAboutToChange(p, pOut);
1945         MemSetTypeFlag(pOut, MEM_Null);
1946         REGISTER_TRACE(pOp->p2, pOut);
1947       }else{
1948         VdbeBranchTaken(2,3);
1949         if( pOp->p5 & SQLITE_JUMPIFNULL ){
1950           goto jump_to_p2;
1951         }
1952       }
1953       break;
1954     }
1955   }else{
1956     /* Neither operand is NULL.  Do a comparison. */
1957     affinity = pOp->p5 & SQLITE_AFF_MASK;
1958     if( affinity>=SQLITE_AFF_NUMERIC ){
1959       if( (flags1 | flags3)&MEM_Str ){
1960         if( (flags1 & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
1961           applyNumericAffinity(pIn1,0);
1962           assert( flags3==pIn3->flags );
1963           /* testcase( flags3!=pIn3->flags );
1964           ** this used to be possible with pIn1==pIn3, but not since
1965           ** the column cache was removed.  The following assignment
1966           ** is essentially a no-op.  But, it provides defense-in-depth
1967           ** in case our analysis is incorrect, so it is left in. */
1968           flags3 = pIn3->flags;
1969         }
1970         if( (flags3 & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
1971           applyNumericAffinity(pIn3,0);
1972         }
1973       }
1974       /* Handle the common case of integer comparison here, as an
1975       ** optimization, to avoid a call to sqlite3MemCompare() */
1976       if( (pIn1->flags & pIn3->flags & MEM_Int)!=0 ){
1977         if( pIn3->u.i > pIn1->u.i ){ res = +1; goto compare_op; }
1978         if( pIn3->u.i < pIn1->u.i ){ res = -1; goto compare_op; }
1979         res = 0;
1980         goto compare_op;
1981       }
1982     }else if( affinity==SQLITE_AFF_TEXT ){
1983       if( (flags1 & MEM_Str)==0 && (flags1 & (MEM_Int|MEM_Real))!=0 ){
1984         testcase( pIn1->flags & MEM_Int );
1985         testcase( pIn1->flags & MEM_Real );
1986         sqlite3VdbeMemStringify(pIn1, encoding, 1);
1987         testcase( (flags1&MEM_Dyn) != (pIn1->flags&MEM_Dyn) );
1988         flags1 = (pIn1->flags & ~MEM_TypeMask) | (flags1 & MEM_TypeMask);
1989         assert( pIn1!=pIn3 );
1990       }
1991       if( (flags3 & MEM_Str)==0 && (flags3 & (MEM_Int|MEM_Real))!=0 ){
1992         testcase( pIn3->flags & MEM_Int );
1993         testcase( pIn3->flags & MEM_Real );
1994         sqlite3VdbeMemStringify(pIn3, encoding, 1);
1995         testcase( (flags3&MEM_Dyn) != (pIn3->flags&MEM_Dyn) );
1996         flags3 = (pIn3->flags & ~MEM_TypeMask) | (flags3 & MEM_TypeMask);
1997       }
1998     }
1999     assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );
2000     res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);
2001   }
2002 compare_op:
2003   /* At this point, res is negative, zero, or positive if reg[P1] is
2004   ** less than, equal to, or greater than reg[P3], respectively.  Compute
2005   ** the answer to this operator in res2, depending on what the comparison
2006   ** operator actually is.  The next block of code depends on the fact
2007   ** that the 6 comparison operators are consecutive integers in this
2008   ** order:  NE, EQ, GT, LE, LT, GE */
2009   assert( OP_Eq==OP_Ne+1 ); assert( OP_Gt==OP_Ne+2 ); assert( OP_Le==OP_Ne+3 );
2010   assert( OP_Lt==OP_Ne+4 ); assert( OP_Ge==OP_Ne+5 );
2011   if( res<0 ){                        /* ne, eq, gt, le, lt, ge */
2012     static const unsigned char aLTb[] = { 1,  0,  0,  1,  1,  0 };
2013     res2 = aLTb[pOp->opcode - OP_Ne];
2014   }else if( res==0 ){
2015     static const unsigned char aEQb[] = { 0,  1,  0,  1,  0,  1 };
2016     res2 = aEQb[pOp->opcode - OP_Ne];
2017   }else{
2018     static const unsigned char aGTb[] = { 1,  0,  1,  0,  0,  1 };
2019     res2 = aGTb[pOp->opcode - OP_Ne];
2020   }
2021 
2022   /* Undo any changes made by applyAffinity() to the input registers. */
2023   assert( (pIn1->flags & MEM_Dyn) == (flags1 & MEM_Dyn) );
2024   pIn1->flags = flags1;
2025   assert( (pIn3->flags & MEM_Dyn) == (flags3 & MEM_Dyn) );
2026   pIn3->flags = flags3;
2027 
2028   if( pOp->p5 & SQLITE_STOREP2 ){
2029     pOut = &aMem[pOp->p2];
2030     iCompare = res;
2031     if( (pOp->p5 & SQLITE_KEEPNULL)!=0 ){
2032       /* The KEEPNULL flag prevents OP_Eq from overwriting a NULL with 1
2033       ** and prevents OP_Ne from overwriting NULL with 0.  This flag
2034       ** is only used in contexts where either:
2035       **   (1) op==OP_Eq && (r[P2]==NULL || r[P2]==0)
2036       **   (2) op==OP_Ne && (r[P2]==NULL || r[P2]==1)
2037       ** Therefore it is not necessary to check the content of r[P2] for
2038       ** NULL. */
2039       assert( pOp->opcode==OP_Ne || pOp->opcode==OP_Eq );
2040       assert( res2==0 || res2==1 );
2041       testcase( res2==0 && pOp->opcode==OP_Eq );
2042       testcase( res2==1 && pOp->opcode==OP_Eq );
2043       testcase( res2==0 && pOp->opcode==OP_Ne );
2044       testcase( res2==1 && pOp->opcode==OP_Ne );
2045       if( (pOp->opcode==OP_Eq)==res2 ) break;
2046     }
2047     memAboutToChange(p, pOut);
2048     MemSetTypeFlag(pOut, MEM_Int);
2049     pOut->u.i = res2;
2050     REGISTER_TRACE(pOp->p2, pOut);
2051   }else{
2052     VdbeBranchTaken(res!=0, (pOp->p5 & SQLITE_NULLEQ)?2:3);
2053     if( res2 ){
2054       goto jump_to_p2;
2055     }
2056   }
2057   break;
2058 }
2059 
2060 /* Opcode: ElseNotEq * P2 * * *
2061 **
2062 ** This opcode must immediately follow an OP_Lt or OP_Gt comparison operator.
2063 ** If result of an OP_Eq comparison on the same two operands
2064 ** would have be NULL or false (0), then then jump to P2.
2065 ** If the result of an OP_Eq comparison on the two previous operands
2066 ** would have been true (1), then fall through.
2067 */
2068 case OP_ElseNotEq: {       /* same as TK_ESCAPE, jump */
2069   assert( pOp>aOp );
2070   assert( pOp[-1].opcode==OP_Lt || pOp[-1].opcode==OP_Gt );
2071   assert( pOp[-1].p5 & SQLITE_STOREP2 );
2072   VdbeBranchTaken(iCompare!=0, 2);
2073   if( iCompare!=0 ) goto jump_to_p2;
2074   break;
2075 }
2076 
2077 
2078 /* Opcode: Permutation * * * P4 *
2079 **
2080 ** Set the permutation used by the OP_Compare operator in the next
2081 ** instruction.  The permutation is stored in the P4 operand.
2082 **
2083 ** The permutation is only valid until the next OP_Compare that has
2084 ** the OPFLAG_PERMUTE bit set in P5. Typically the OP_Permutation should
2085 ** occur immediately prior to the OP_Compare.
2086 **
2087 ** The first integer in the P4 integer array is the length of the array
2088 ** and does not become part of the permutation.
2089 */
2090 case OP_Permutation: {
2091   assert( pOp->p4type==P4_INTARRAY );
2092   assert( pOp->p4.ai );
2093   assert( pOp[1].opcode==OP_Compare );
2094   assert( pOp[1].p5 & OPFLAG_PERMUTE );
2095   break;
2096 }
2097 
2098 /* Opcode: Compare P1 P2 P3 P4 P5
2099 ** Synopsis: r[P1@P3] <-> r[P2@P3]
2100 **
2101 ** Compare two vectors of registers in reg(P1)..reg(P1+P3-1) (call this
2102 ** vector "A") and in reg(P2)..reg(P2+P3-1) ("B").  Save the result of
2103 ** the comparison for use by the next OP_Jump instruct.
2104 **
2105 ** If P5 has the OPFLAG_PERMUTE bit set, then the order of comparison is
2106 ** determined by the most recent OP_Permutation operator.  If the
2107 ** OPFLAG_PERMUTE bit is clear, then register are compared in sequential
2108 ** order.
2109 **
2110 ** P4 is a KeyInfo structure that defines collating sequences and sort
2111 ** orders for the comparison.  The permutation applies to registers
2112 ** only.  The KeyInfo elements are used sequentially.
2113 **
2114 ** The comparison is a sort comparison, so NULLs compare equal,
2115 ** NULLs are less than numbers, numbers are less than strings,
2116 ** and strings are less than blobs.
2117 */
2118 case OP_Compare: {
2119   int n;
2120   int i;
2121   int p1;
2122   int p2;
2123   const KeyInfo *pKeyInfo;
2124   int idx;
2125   CollSeq *pColl;    /* Collating sequence to use on this term */
2126   int bRev;          /* True for DESCENDING sort order */
2127   int *aPermute;     /* The permutation */
2128 
2129   if( (pOp->p5 & OPFLAG_PERMUTE)==0 ){
2130     aPermute = 0;
2131   }else{
2132     assert( pOp>aOp );
2133     assert( pOp[-1].opcode==OP_Permutation );
2134     assert( pOp[-1].p4type==P4_INTARRAY );
2135     aPermute = pOp[-1].p4.ai + 1;
2136     assert( aPermute!=0 );
2137   }
2138   n = pOp->p3;
2139   pKeyInfo = pOp->p4.pKeyInfo;
2140   assert( n>0 );
2141   assert( pKeyInfo!=0 );
2142   p1 = pOp->p1;
2143   p2 = pOp->p2;
2144 #ifdef SQLITE_DEBUG
2145   if( aPermute ){
2146     int k, mx = 0;
2147     for(k=0; k<n; k++) if( aPermute[k]>mx ) mx = aPermute[k];
2148     assert( p1>0 && p1+mx<=(p->nMem+1 - p->nCursor)+1 );
2149     assert( p2>0 && p2+mx<=(p->nMem+1 - p->nCursor)+1 );
2150   }else{
2151     assert( p1>0 && p1+n<=(p->nMem+1 - p->nCursor)+1 );
2152     assert( p2>0 && p2+n<=(p->nMem+1 - p->nCursor)+1 );
2153   }
2154 #endif /* SQLITE_DEBUG */
2155   for(i=0; i<n; i++){
2156     idx = aPermute ? aPermute[i] : i;
2157     assert( memIsValid(&aMem[p1+idx]) );
2158     assert( memIsValid(&aMem[p2+idx]) );
2159     REGISTER_TRACE(p1+idx, &aMem[p1+idx]);
2160     REGISTER_TRACE(p2+idx, &aMem[p2+idx]);
2161     assert( i<pKeyInfo->nKeyField );
2162     pColl = pKeyInfo->aColl[i];
2163     bRev = pKeyInfo->aSortOrder[i];
2164     iCompare = sqlite3MemCompare(&aMem[p1+idx], &aMem[p2+idx], pColl);
2165     if( iCompare ){
2166       if( bRev ) iCompare = -iCompare;
2167       break;
2168     }
2169   }
2170   break;
2171 }
2172 
2173 /* Opcode: Jump P1 P2 P3 * *
2174 **
2175 ** Jump to the instruction at address P1, P2, or P3 depending on whether
2176 ** in the most recent OP_Compare instruction the P1 vector was less than
2177 ** equal to, or greater than the P2 vector, respectively.
2178 */
2179 case OP_Jump: {             /* jump */
2180   if( iCompare<0 ){
2181     VdbeBranchTaken(0,4); pOp = &aOp[pOp->p1 - 1];
2182   }else if( iCompare==0 ){
2183     VdbeBranchTaken(1,4); pOp = &aOp[pOp->p2 - 1];
2184   }else{
2185     VdbeBranchTaken(2,4); pOp = &aOp[pOp->p3 - 1];
2186   }
2187   break;
2188 }
2189 
2190 /* Opcode: And P1 P2 P3 * *
2191 ** Synopsis: r[P3]=(r[P1] && r[P2])
2192 **
2193 ** Take the logical AND of the values in registers P1 and P2 and
2194 ** write the result into register P3.
2195 **
2196 ** If either P1 or P2 is 0 (false) then the result is 0 even if
2197 ** the other input is NULL.  A NULL and true or two NULLs give
2198 ** a NULL output.
2199 */
2200 /* Opcode: Or P1 P2 P3 * *
2201 ** Synopsis: r[P3]=(r[P1] || r[P2])
2202 **
2203 ** Take the logical OR of the values in register P1 and P2 and
2204 ** store the answer in register P3.
2205 **
2206 ** If either P1 or P2 is nonzero (true) then the result is 1 (true)
2207 ** even if the other input is NULL.  A NULL and false or two NULLs
2208 ** give a NULL output.
2209 */
2210 case OP_And:              /* same as TK_AND, in1, in2, out3 */
2211 case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
2212   int v1;    /* Left operand:  0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
2213   int v2;    /* Right operand: 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
2214 
2215   v1 = sqlite3VdbeBooleanValue(&aMem[pOp->p1], 2);
2216   v2 = sqlite3VdbeBooleanValue(&aMem[pOp->p2], 2);
2217   if( pOp->opcode==OP_And ){
2218     static const unsigned char and_logic[] = { 0, 0, 0, 0, 1, 2, 0, 2, 2 };
2219     v1 = and_logic[v1*3+v2];
2220   }else{
2221     static const unsigned char or_logic[] = { 0, 1, 2, 1, 1, 1, 2, 1, 2 };
2222     v1 = or_logic[v1*3+v2];
2223   }
2224   pOut = &aMem[pOp->p3];
2225   if( v1==2 ){
2226     MemSetTypeFlag(pOut, MEM_Null);
2227   }else{
2228     pOut->u.i = v1;
2229     MemSetTypeFlag(pOut, MEM_Int);
2230   }
2231   break;
2232 }
2233 
2234 /* Opcode: IsTrue P1 P2 P3 P4 *
2235 ** Synopsis: r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4
2236 **
2237 ** This opcode implements the IS TRUE, IS FALSE, IS NOT TRUE, and
2238 ** IS NOT FALSE operators.
2239 **
2240 ** Interpret the value in register P1 as a boolean value.  Store that
2241 ** boolean (a 0 or 1) in register P2.  Or if the value in register P1 is
2242 ** NULL, then the P3 is stored in register P2.  Invert the answer if P4
2243 ** is 1.
2244 **
2245 ** The logic is summarized like this:
2246 **
2247 ** <ul>
2248 ** <li> If P3==0 and P4==0  then  r[P2] := r[P1] IS TRUE
2249 ** <li> If P3==1 and P4==1  then  r[P2] := r[P1] IS FALSE
2250 ** <li> If P3==0 and P4==1  then  r[P2] := r[P1] IS NOT TRUE
2251 ** <li> If P3==1 and P4==0  then  r[P2] := r[P1] IS NOT FALSE
2252 ** </ul>
2253 */
2254 case OP_IsTrue: {               /* in1, out2 */
2255   assert( pOp->p4type==P4_INT32 );
2256   assert( pOp->p4.i==0 || pOp->p4.i==1 );
2257   assert( pOp->p3==0 || pOp->p3==1 );
2258   sqlite3VdbeMemSetInt64(&aMem[pOp->p2],
2259       sqlite3VdbeBooleanValue(&aMem[pOp->p1], pOp->p3) ^ pOp->p4.i);
2260   break;
2261 }
2262 
2263 /* Opcode: Not P1 P2 * * *
2264 ** Synopsis: r[P2]= !r[P1]
2265 **
2266 ** Interpret the value in register P1 as a boolean value.  Store the
2267 ** boolean complement in register P2.  If the value in register P1 is
2268 ** NULL, then a NULL is stored in P2.
2269 */
2270 case OP_Not: {                /* same as TK_NOT, in1, out2 */
2271   pIn1 = &aMem[pOp->p1];
2272   pOut = &aMem[pOp->p2];
2273   if( (pIn1->flags & MEM_Null)==0 ){
2274     sqlite3VdbeMemSetInt64(pOut, !sqlite3VdbeBooleanValue(pIn1,0));
2275   }else{
2276     sqlite3VdbeMemSetNull(pOut);
2277   }
2278   break;
2279 }
2280 
2281 /* Opcode: BitNot P1 P2 * * *
2282 ** Synopsis: r[P2]= ~r[P1]
2283 **
2284 ** Interpret the content of register P1 as an integer.  Store the
2285 ** ones-complement of the P1 value into register P2.  If P1 holds
2286 ** a NULL then store a NULL in P2.
2287 */
2288 case OP_BitNot: {             /* same as TK_BITNOT, in1, out2 */
2289   pIn1 = &aMem[pOp->p1];
2290   pOut = &aMem[pOp->p2];
2291   sqlite3VdbeMemSetNull(pOut);
2292   if( (pIn1->flags & MEM_Null)==0 ){
2293     pOut->flags = MEM_Int;
2294     pOut->u.i = ~sqlite3VdbeIntValue(pIn1);
2295   }
2296   break;
2297 }
2298 
2299 /* Opcode: Once P1 P2 * * *
2300 **
2301 ** Fall through to the next instruction the first time this opcode is
2302 ** encountered on each invocation of the byte-code program.  Jump to P2
2303 ** on the second and all subsequent encounters during the same invocation.
2304 **
2305 ** Top-level programs determine first invocation by comparing the P1
2306 ** operand against the P1 operand on the OP_Init opcode at the beginning
2307 ** of the program.  If the P1 values differ, then fall through and make
2308 ** the P1 of this opcode equal to the P1 of OP_Init.  If P1 values are
2309 ** the same then take the jump.
2310 **
2311 ** For subprograms, there is a bitmask in the VdbeFrame that determines
2312 ** whether or not the jump should be taken.  The bitmask is necessary
2313 ** because the self-altering code trick does not work for recursive
2314 ** triggers.
2315 */
2316 case OP_Once: {             /* jump */
2317   u32 iAddr;                /* Address of this instruction */
2318   assert( p->aOp[0].opcode==OP_Init );
2319   if( p->pFrame ){
2320     iAddr = (int)(pOp - p->aOp);
2321     if( (p->pFrame->aOnce[iAddr/8] & (1<<(iAddr & 7)))!=0 ){
2322       VdbeBranchTaken(1, 2);
2323       goto jump_to_p2;
2324     }
2325     p->pFrame->aOnce[iAddr/8] |= 1<<(iAddr & 7);
2326   }else{
2327     if( p->aOp[0].p1==pOp->p1 ){
2328       VdbeBranchTaken(1, 2);
2329       goto jump_to_p2;
2330     }
2331   }
2332   VdbeBranchTaken(0, 2);
2333   pOp->p1 = p->aOp[0].p1;
2334   break;
2335 }
2336 
2337 /* Opcode: If P1 P2 P3 * *
2338 **
2339 ** Jump to P2 if the value in register P1 is true.  The value
2340 ** is considered true if it is numeric and non-zero.  If the value
2341 ** in P1 is NULL then take the jump if and only if P3 is non-zero.
2342 */
2343 case OP_If:  {               /* jump, in1 */
2344   int c;
2345   c = sqlite3VdbeBooleanValue(&aMem[pOp->p1], pOp->p3);
2346   VdbeBranchTaken(c!=0, 2);
2347   if( c ) goto jump_to_p2;
2348   break;
2349 }
2350 
2351 /* Opcode: IfNot P1 P2 P3 * *
2352 **
2353 ** Jump to P2 if the value in register P1 is False.  The value
2354 ** is considered false if it has a numeric value of zero.  If the value
2355 ** in P1 is NULL then take the jump if and only if P3 is non-zero.
2356 */
2357 case OP_IfNot: {            /* jump, in1 */
2358   int c;
2359   c = !sqlite3VdbeBooleanValue(&aMem[pOp->p1], !pOp->p3);
2360   VdbeBranchTaken(c!=0, 2);
2361   if( c ) goto jump_to_p2;
2362   break;
2363 }
2364 
2365 /* Opcode: IsNull P1 P2 * * *
2366 ** Synopsis: if r[P1]==NULL goto P2
2367 **
2368 ** Jump to P2 if the value in register P1 is NULL.
2369 */
2370 case OP_IsNull: {            /* same as TK_ISNULL, jump, in1 */
2371   pIn1 = &aMem[pOp->p1];
2372   VdbeBranchTaken( (pIn1->flags & MEM_Null)!=0, 2);
2373   if( (pIn1->flags & MEM_Null)!=0 ){
2374     goto jump_to_p2;
2375   }
2376   break;
2377 }
2378 
2379 /* Opcode: NotNull P1 P2 * * *
2380 ** Synopsis: if r[P1]!=NULL goto P2
2381 **
2382 ** Jump to P2 if the value in register P1 is not NULL.
2383 */
2384 case OP_NotNull: {            /* same as TK_NOTNULL, jump, in1 */
2385   pIn1 = &aMem[pOp->p1];
2386   VdbeBranchTaken( (pIn1->flags & MEM_Null)==0, 2);
2387   if( (pIn1->flags & MEM_Null)==0 ){
2388     goto jump_to_p2;
2389   }
2390   break;
2391 }
2392 
2393 /* Opcode: IfNullRow P1 P2 P3 * *
2394 ** Synopsis: if P1.nullRow then r[P3]=NULL, goto P2
2395 **
2396 ** Check the cursor P1 to see if it is currently pointing at a NULL row.
2397 ** If it is, then set register P3 to NULL and jump immediately to P2.
2398 ** If P1 is not on a NULL row, then fall through without making any
2399 ** changes.
2400 */
2401 case OP_IfNullRow: {         /* jump */
2402   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
2403   assert( p->apCsr[pOp->p1]!=0 );
2404   if( p->apCsr[pOp->p1]->nullRow ){
2405     sqlite3VdbeMemSetNull(aMem + pOp->p3);
2406     goto jump_to_p2;
2407   }
2408   break;
2409 }
2410 
2411 #ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
2412 /* Opcode: Offset P1 P2 P3 * *
2413 ** Synopsis: r[P3] = sqlite_offset(P1)
2414 **
2415 ** Store in register r[P3] the byte offset into the database file that is the
2416 ** start of the payload for the record at which that cursor P1 is currently
2417 ** pointing.
2418 **
2419 ** P2 is the column number for the argument to the sqlite_offset() function.
2420 ** This opcode does not use P2 itself, but the P2 value is used by the
2421 ** code generator.  The P1, P2, and P3 operands to this opcode are the
2422 ** same as for OP_Column.
2423 **
2424 ** This opcode is only available if SQLite is compiled with the
2425 ** -DSQLITE_ENABLE_OFFSET_SQL_FUNC option.
2426 */
2427 case OP_Offset: {          /* out3 */
2428   VdbeCursor *pC;    /* The VDBE cursor */
2429   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
2430   pC = p->apCsr[pOp->p1];
2431   pOut = &p->aMem[pOp->p3];
2432   if( NEVER(pC==0) || pC->eCurType!=CURTYPE_BTREE ){
2433     sqlite3VdbeMemSetNull(pOut);
2434   }else{
2435     sqlite3VdbeMemSetInt64(pOut, sqlite3BtreeOffset(pC->uc.pCursor));
2436   }
2437   break;
2438 }
2439 #endif /* SQLITE_ENABLE_OFFSET_SQL_FUNC */
2440 
2441 /* Opcode: Column P1 P2 P3 P4 P5
2442 ** Synopsis: r[P3]=PX
2443 **
2444 ** Interpret the data that cursor P1 points to as a structure built using
2445 ** the MakeRecord instruction.  (See the MakeRecord opcode for additional
2446 ** information about the format of the data.)  Extract the P2-th column
2447 ** from this record.  If there are less that (P2+1)
2448 ** values in the record, extract a NULL.
2449 **
2450 ** The value extracted is stored in register P3.
2451 **
2452 ** If the record contains fewer than P2 fields, then extract a NULL.  Or,
2453 ** if the P4 argument is a P4_MEM use the value of the P4 argument as
2454 ** the result.
2455 **
2456 ** If the OPFLAG_CLEARCACHE bit is set on P5 and P1 is a pseudo-table cursor,
2457 ** then the cache of the cursor is reset prior to extracting the column.
2458 ** The first OP_Column against a pseudo-table after the value of the content
2459 ** register has changed should have this bit set.
2460 **
2461 ** If the OPFLAG_LENGTHARG and OPFLAG_TYPEOFARG bits are set on P5 then
2462 ** the result is guaranteed to only be used as the argument of a length()
2463 ** or typeof() function, respectively.  The loading of large blobs can be
2464 ** skipped for length() and all content loading can be skipped for typeof().
2465 */
2466 case OP_Column: {
2467   int p2;            /* column number to retrieve */
2468   VdbeCursor *pC;    /* The VDBE cursor */
2469   BtCursor *pCrsr;   /* The BTree cursor */
2470   u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
2471   int len;           /* The length of the serialized data for the column */
2472   int i;             /* Loop counter */
2473   Mem *pDest;        /* Where to write the extracted value */
2474   Mem sMem;          /* For storing the record being decoded */
2475   const u8 *zData;   /* Part of the record being decoded */
2476   const u8 *zHdr;    /* Next unparsed byte of the header */
2477   const u8 *zEndHdr; /* Pointer to first byte after the header */
2478   u64 offset64;      /* 64-bit offset */
2479   u32 t;             /* A type code from the record header */
2480   Mem *pReg;         /* PseudoTable input register */
2481 
2482   pC = p->apCsr[pOp->p1];
2483   p2 = pOp->p2;
2484 
2485   /* If the cursor cache is stale (meaning it is not currently point at
2486   ** the correct row) then bring it up-to-date by doing the necessary
2487   ** B-Tree seek. */
2488   rc = sqlite3VdbeCursorMoveto(&pC, &p2);
2489   if( rc ) goto abort_due_to_error;
2490 
2491   assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
2492   pDest = &aMem[pOp->p3];
2493   memAboutToChange(p, pDest);
2494   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
2495   assert( pC!=0 );
2496   assert( p2<pC->nField );
2497   aOffset = pC->aOffset;
2498   assert( pC->eCurType!=CURTYPE_VTAB );
2499   assert( pC->eCurType!=CURTYPE_PSEUDO || pC->nullRow );
2500   assert( pC->eCurType!=CURTYPE_SORTER );
2501 
2502   if( pC->cacheStatus!=p->cacheCtr ){                /*OPTIMIZATION-IF-FALSE*/
2503     if( pC->nullRow ){
2504       if( pC->eCurType==CURTYPE_PSEUDO ){
2505         /* For the special case of as pseudo-cursor, the seekResult field
2506         ** identifies the register that holds the record */
2507         assert( pC->seekResult>0 );
2508         pReg = &aMem[pC->seekResult];
2509         assert( pReg->flags & MEM_Blob );
2510         assert( memIsValid(pReg) );
2511         pC->payloadSize = pC->szRow = pReg->n;
2512         pC->aRow = (u8*)pReg->z;
2513       }else{
2514         sqlite3VdbeMemSetNull(pDest);
2515         goto op_column_out;
2516       }
2517     }else{
2518       pCrsr = pC->uc.pCursor;
2519       assert( pC->eCurType==CURTYPE_BTREE );
2520       assert( pCrsr );
2521       assert( sqlite3BtreeCursorIsValid(pCrsr) );
2522       pC->payloadSize = sqlite3BtreePayloadSize(pCrsr);
2523       pC->aRow = sqlite3BtreePayloadFetch(pCrsr, &pC->szRow);
2524       assert( pC->szRow<=pC->payloadSize );
2525       assert( pC->szRow<=65536 );  /* Maximum page size is 64KiB */
2526       if( pC->payloadSize > (u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
2527         goto too_big;
2528       }
2529     }
2530     pC->cacheStatus = p->cacheCtr;
2531     pC->iHdrOffset = getVarint32(pC->aRow, aOffset[0]);
2532     pC->nHdrParsed = 0;
2533 
2534 
2535     if( pC->szRow<aOffset[0] ){      /*OPTIMIZATION-IF-FALSE*/
2536       /* pC->aRow does not have to hold the entire row, but it does at least
2537       ** need to cover the header of the record.  If pC->aRow does not contain
2538       ** the complete header, then set it to zero, forcing the header to be
2539       ** dynamically allocated. */
2540       pC->aRow = 0;
2541       pC->szRow = 0;
2542 
2543       /* Make sure a corrupt database has not given us an oversize header.
2544       ** Do this now to avoid an oversize memory allocation.
2545       **
2546       ** Type entries can be between 1 and 5 bytes each.  But 4 and 5 byte
2547       ** types use so much data space that there can only be 4096 and 32 of
2548       ** them, respectively.  So the maximum header length results from a
2549       ** 3-byte type for each of the maximum of 32768 columns plus three
2550       ** extra bytes for the header length itself.  32768*3 + 3 = 98307.
2551       */
2552       if( aOffset[0] > 98307 || aOffset[0] > pC->payloadSize ){
2553         goto op_column_corrupt;
2554       }
2555     }else{
2556       /* This is an optimization.  By skipping over the first few tests
2557       ** (ex: pC->nHdrParsed<=p2) in the next section, we achieve a
2558       ** measurable performance gain.
2559       **
2560       ** This branch is taken even if aOffset[0]==0.  Such a record is never
2561       ** generated by SQLite, and could be considered corruption, but we
2562       ** accept it for historical reasons.  When aOffset[0]==0, the code this
2563       ** branch jumps to reads past the end of the record, but never more
2564       ** than a few bytes.  Even if the record occurs at the end of the page
2565       ** content area, the "page header" comes after the page content and so
2566       ** this overread is harmless.  Similar overreads can occur for a corrupt
2567       ** database file.
2568       */
2569       zData = pC->aRow;
2570       assert( pC->nHdrParsed<=p2 );         /* Conditional skipped */
2571       testcase( aOffset[0]==0 );
2572       goto op_column_read_header;
2573     }
2574   }
2575 
2576   /* Make sure at least the first p2+1 entries of the header have been
2577   ** parsed and valid information is in aOffset[] and pC->aType[].
2578   */
2579   if( pC->nHdrParsed<=p2 ){
2580     /* If there is more header available for parsing in the record, try
2581     ** to extract additional fields up through the p2+1-th field
2582     */
2583     if( pC->iHdrOffset<aOffset[0] ){
2584       /* Make sure zData points to enough of the record to cover the header. */
2585       if( pC->aRow==0 ){
2586         memset(&sMem, 0, sizeof(sMem));
2587         rc = sqlite3VdbeMemFromBtree(pC->uc.pCursor, 0, aOffset[0], &sMem);
2588         if( rc!=SQLITE_OK ) goto abort_due_to_error;
2589         zData = (u8*)sMem.z;
2590       }else{
2591         zData = pC->aRow;
2592       }
2593 
2594       /* Fill in pC->aType[i] and aOffset[i] values through the p2-th field. */
2595     op_column_read_header:
2596       i = pC->nHdrParsed;
2597       offset64 = aOffset[i];
2598       zHdr = zData + pC->iHdrOffset;
2599       zEndHdr = zData + aOffset[0];
2600       testcase( zHdr>=zEndHdr );
2601       do{
2602         if( (t = zHdr[0])<0x80 ){
2603           zHdr++;
2604           offset64 += sqlite3VdbeOneByteSerialTypeLen(t);
2605         }else{
2606           zHdr += sqlite3GetVarint32(zHdr, &t);
2607           offset64 += sqlite3VdbeSerialTypeLen(t);
2608         }
2609         pC->aType[i++] = t;
2610         aOffset[i] = (u32)(offset64 & 0xffffffff);
2611       }while( i<=p2 && zHdr<zEndHdr );
2612 
2613       /* The record is corrupt if any of the following are true:
2614       ** (1) the bytes of the header extend past the declared header size
2615       ** (2) the entire header was used but not all data was used
2616       ** (3) the end of the data extends beyond the end of the record.
2617       */
2618       if( (zHdr>=zEndHdr && (zHdr>zEndHdr || offset64!=pC->payloadSize))
2619        || (offset64 > pC->payloadSize)
2620       ){
2621         if( aOffset[0]==0 ){
2622           i = 0;
2623           zHdr = zEndHdr;
2624         }else{
2625           if( pC->aRow==0 ) sqlite3VdbeMemRelease(&sMem);
2626           goto op_column_corrupt;
2627         }
2628       }
2629 
2630       pC->nHdrParsed = i;
2631       pC->iHdrOffset = (u32)(zHdr - zData);
2632       if( pC->aRow==0 ) sqlite3VdbeMemRelease(&sMem);
2633     }else{
2634       t = 0;
2635     }
2636 
2637     /* If after trying to extract new entries from the header, nHdrParsed is
2638     ** still not up to p2, that means that the record has fewer than p2
2639     ** columns.  So the result will be either the default value or a NULL.
2640     */
2641     if( pC->nHdrParsed<=p2 ){
2642       if( pOp->p4type==P4_MEM ){
2643         sqlite3VdbeMemShallowCopy(pDest, pOp->p4.pMem, MEM_Static);
2644       }else{
2645         sqlite3VdbeMemSetNull(pDest);
2646       }
2647       goto op_column_out;
2648     }
2649   }else{
2650     t = pC->aType[p2];
2651   }
2652 
2653   /* Extract the content for the p2+1-th column.  Control can only
2654   ** reach this point if aOffset[p2], aOffset[p2+1], and pC->aType[p2] are
2655   ** all valid.
2656   */
2657   assert( p2<pC->nHdrParsed );
2658   assert( rc==SQLITE_OK );
2659   assert( sqlite3VdbeCheckMemInvariants(pDest) );
2660   if( VdbeMemDynamic(pDest) ){
2661     sqlite3VdbeMemSetNull(pDest);
2662   }
2663   assert( t==pC->aType[p2] );
2664   if( pC->szRow>=aOffset[p2+1] ){
2665     /* This is the common case where the desired content fits on the original
2666     ** page - where the content is not on an overflow page */
2667     zData = pC->aRow + aOffset[p2];
2668     if( t<12 ){
2669       sqlite3VdbeSerialGet(zData, t, pDest);
2670     }else{
2671       /* If the column value is a string, we need a persistent value, not
2672       ** a MEM_Ephem value.  This branch is a fast short-cut that is equivalent
2673       ** to calling sqlite3VdbeSerialGet() and sqlite3VdbeDeephemeralize().
2674       */
2675       static const u16 aFlag[] = { MEM_Blob, MEM_Str|MEM_Term };
2676       pDest->n = len = (t-12)/2;
2677       pDest->enc = encoding;
2678       if( pDest->szMalloc < len+2 ){
2679         pDest->flags = MEM_Null;
2680         if( sqlite3VdbeMemGrow(pDest, len+2, 0) ) goto no_mem;
2681       }else{
2682         pDest->z = pDest->zMalloc;
2683       }
2684       memcpy(pDest->z, zData, len);
2685       pDest->z[len] = 0;
2686       pDest->z[len+1] = 0;
2687       pDest->flags = aFlag[t&1];
2688     }
2689   }else{
2690     pDest->enc = encoding;
2691     /* This branch happens only when content is on overflow pages */
2692     if( ((pOp->p5 & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG))!=0
2693           && ((t>=12 && (t&1)==0) || (pOp->p5 & OPFLAG_TYPEOFARG)!=0))
2694      || (len = sqlite3VdbeSerialTypeLen(t))==0
2695     ){
2696       /* Content is irrelevant for
2697       **    1. the typeof() function,
2698       **    2. the length(X) function if X is a blob, and
2699       **    3. if the content length is zero.
2700       ** So we might as well use bogus content rather than reading
2701       ** content from disk.
2702       **
2703       ** Although sqlite3VdbeSerialGet() may read at most 8 bytes from the
2704       ** buffer passed to it, debugging function VdbeMemPrettyPrint() may
2705       ** read up to 16. So 16 bytes of bogus content is supplied.
2706       */
2707       static u8 aZero[16];  /* This is the bogus content */
2708       sqlite3VdbeSerialGet(aZero, t, pDest);
2709     }else{
2710       rc = sqlite3VdbeMemFromBtree(pC->uc.pCursor, aOffset[p2], len, pDest);
2711       if( rc!=SQLITE_OK ) goto abort_due_to_error;
2712       sqlite3VdbeSerialGet((const u8*)pDest->z, t, pDest);
2713       pDest->flags &= ~MEM_Ephem;
2714     }
2715   }
2716 
2717 op_column_out:
2718   UPDATE_MAX_BLOBSIZE(pDest);
2719   REGISTER_TRACE(pOp->p3, pDest);
2720   break;
2721 
2722 op_column_corrupt:
2723   if( aOp[0].p3>0 ){
2724     pOp = &aOp[aOp[0].p3-1];
2725     break;
2726   }else{
2727     rc = SQLITE_CORRUPT_BKPT;
2728     goto abort_due_to_error;
2729   }
2730 }
2731 
2732 /* Opcode: Affinity P1 P2 * P4 *
2733 ** Synopsis: affinity(r[P1@P2])
2734 **
2735 ** Apply affinities to a range of P2 registers starting with P1.
2736 **
2737 ** P4 is a string that is P2 characters long. The N-th character of the
2738 ** string indicates the column affinity that should be used for the N-th
2739 ** memory cell in the range.
2740 */
2741 case OP_Affinity: {
2742   const char *zAffinity;   /* The affinity to be applied */
2743 
2744   zAffinity = pOp->p4.z;
2745   assert( zAffinity!=0 );
2746   assert( pOp->p2>0 );
2747   assert( zAffinity[pOp->p2]==0 );
2748   pIn1 = &aMem[pOp->p1];
2749   do{
2750     assert( pIn1 <= &p->aMem[(p->nMem+1 - p->nCursor)] );
2751     assert( memIsValid(pIn1) );
2752     applyAffinity(pIn1, *(zAffinity++), encoding);
2753     pIn1++;
2754   }while( zAffinity[0] );
2755   break;
2756 }
2757 
2758 /* Opcode: MakeRecord P1 P2 P3 P4 *
2759 ** Synopsis: r[P3]=mkrec(r[P1@P2])
2760 **
2761 ** Convert P2 registers beginning with P1 into the [record format]
2762 ** use as a data record in a database table or as a key
2763 ** in an index.  The OP_Column opcode can decode the record later.
2764 **
2765 ** P4 may be a string that is P2 characters long.  The N-th character of the
2766 ** string indicates the column affinity that should be used for the N-th
2767 ** field of the index key.
2768 **
2769 ** The mapping from character to affinity is given by the SQLITE_AFF_
2770 ** macros defined in sqliteInt.h.
2771 **
2772 ** If P4 is NULL then all index fields have the affinity BLOB.
2773 */
2774 case OP_MakeRecord: {
2775   u8 *zNewRecord;        /* A buffer to hold the data for the new record */
2776   Mem *pRec;             /* The new record */
2777   u64 nData;             /* Number of bytes of data space */
2778   int nHdr;              /* Number of bytes of header space */
2779   i64 nByte;             /* Data space required for this record */
2780   i64 nZero;             /* Number of zero bytes at the end of the record */
2781   int nVarint;           /* Number of bytes in a varint */
2782   u32 serial_type;       /* Type field */
2783   Mem *pData0;           /* First field to be combined into the record */
2784   Mem *pLast;            /* Last field of the record */
2785   int nField;            /* Number of fields in the record */
2786   char *zAffinity;       /* The affinity string for the record */
2787   int file_format;       /* File format to use for encoding */
2788   int i;                 /* Space used in zNewRecord[] header */
2789   int j;                 /* Space used in zNewRecord[] content */
2790   u32 len;               /* Length of a field */
2791 
2792   /* Assuming the record contains N fields, the record format looks
2793   ** like this:
2794   **
2795   ** ------------------------------------------------------------------------
2796   ** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 |
2797   ** ------------------------------------------------------------------------
2798   **
2799   ** Data(0) is taken from register P1.  Data(1) comes from register P1+1
2800   ** and so forth.
2801   **
2802   ** Each type field is a varint representing the serial type of the
2803   ** corresponding data element (see sqlite3VdbeSerialType()). The
2804   ** hdr-size field is also a varint which is the offset from the beginning
2805   ** of the record to data0.
2806   */
2807   nData = 0;         /* Number of bytes of data space */
2808   nHdr = 0;          /* Number of bytes of header space */
2809   nZero = 0;         /* Number of zero bytes at the end of the record */
2810   nField = pOp->p1;
2811   zAffinity = pOp->p4.z;
2812   assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=(p->nMem+1 - p->nCursor)+1 );
2813   pData0 = &aMem[nField];
2814   nField = pOp->p2;
2815   pLast = &pData0[nField-1];
2816   file_format = p->minWriteFileFormat;
2817 
2818   /* Identify the output register */
2819   assert( pOp->p3<pOp->p1 || pOp->p3>=pOp->p1+pOp->p2 );
2820   pOut = &aMem[pOp->p3];
2821   memAboutToChange(p, pOut);
2822 
2823   /* Apply the requested affinity to all inputs
2824   */
2825   assert( pData0<=pLast );
2826   if( zAffinity ){
2827     pRec = pData0;
2828     do{
2829       applyAffinity(pRec++, *(zAffinity++), encoding);
2830       assert( zAffinity[0]==0 || pRec<=pLast );
2831     }while( zAffinity[0] );
2832   }
2833 
2834 #ifdef SQLITE_ENABLE_NULL_TRIM
2835   /* NULLs can be safely trimmed from the end of the record, as long as
2836   ** as the schema format is 2 or more and none of the omitted columns
2837   ** have a non-NULL default value.  Also, the record must be left with
2838   ** at least one field.  If P5>0 then it will be one more than the
2839   ** index of the right-most column with a non-NULL default value */
2840   if( pOp->p5 ){
2841     while( (pLast->flags & MEM_Null)!=0 && nField>pOp->p5 ){
2842       pLast--;
2843       nField--;
2844     }
2845   }
2846 #endif
2847 
2848   /* Loop through the elements that will make up the record to figure
2849   ** out how much space is required for the new record.
2850   */
2851   pRec = pLast;
2852   do{
2853     assert( memIsValid(pRec) );
2854     serial_type = sqlite3VdbeSerialType(pRec, file_format, &len);
2855     if( pRec->flags & MEM_Zero ){
2856       if( serial_type==0 ){
2857         /* Values with MEM_Null and MEM_Zero are created by xColumn virtual
2858         ** table methods that never invoke sqlite3_result_xxxxx() while
2859         ** computing an unchanging column value in an UPDATE statement.
2860         ** Give such values a special internal-use-only serial-type of 10
2861         ** so that they can be passed through to xUpdate and have
2862         ** a true sqlite3_value_nochange(). */
2863         assert( pOp->p5==OPFLAG_NOCHNG_MAGIC || CORRUPT_DB );
2864         serial_type = 10;
2865       }else if( nData ){
2866         if( sqlite3VdbeMemExpandBlob(pRec) ) goto no_mem;
2867       }else{
2868         nZero += pRec->u.nZero;
2869         len -= pRec->u.nZero;
2870       }
2871     }
2872     nData += len;
2873     testcase( serial_type==127 );
2874     testcase( serial_type==128 );
2875     nHdr += serial_type<=127 ? 1 : sqlite3VarintLen(serial_type);
2876     pRec->uTemp = serial_type;
2877     if( pRec==pData0 ) break;
2878     pRec--;
2879   }while(1);
2880 
2881   /* EVIDENCE-OF: R-22564-11647 The header begins with a single varint
2882   ** which determines the total number of bytes in the header. The varint
2883   ** value is the size of the header in bytes including the size varint
2884   ** itself. */
2885   testcase( nHdr==126 );
2886   testcase( nHdr==127 );
2887   if( nHdr<=126 ){
2888     /* The common case */
2889     nHdr += 1;
2890   }else{
2891     /* Rare case of a really large header */
2892     nVarint = sqlite3VarintLen(nHdr);
2893     nHdr += nVarint;
2894     if( nVarint<sqlite3VarintLen(nHdr) ) nHdr++;
2895   }
2896   nByte = nHdr+nData;
2897 
2898   /* Make sure the output register has a buffer large enough to store
2899   ** the new record. The output register (pOp->p3) is not allowed to
2900   ** be one of the input registers (because the following call to
2901   ** sqlite3VdbeMemClearAndResize() could clobber the value before it is used).
2902   */
2903   if( nByte+nZero<=pOut->szMalloc ){
2904     /* The output register is already large enough to hold the record.
2905     ** No error checks or buffer enlargement is required */
2906     pOut->z = pOut->zMalloc;
2907   }else{
2908     /* Need to make sure that the output is not too big and then enlarge
2909     ** the output register to hold the full result */
2910     if( nByte+nZero>db->aLimit[SQLITE_LIMIT_LENGTH] ){
2911       goto too_big;
2912     }
2913     if( sqlite3VdbeMemClearAndResize(pOut, (int)nByte) ){
2914       goto no_mem;
2915     }
2916   }
2917   zNewRecord = (u8 *)pOut->z;
2918 
2919   /* Write the record */
2920   i = putVarint32(zNewRecord, nHdr);
2921   j = nHdr;
2922   assert( pData0<=pLast );
2923   pRec = pData0;
2924   do{
2925     serial_type = pRec->uTemp;
2926     /* EVIDENCE-OF: R-06529-47362 Following the size varint are one or more
2927     ** additional varints, one per column. */
2928     i += putVarint32(&zNewRecord[i], serial_type);            /* serial type */
2929     /* EVIDENCE-OF: R-64536-51728 The values for each column in the record
2930     ** immediately follow the header. */
2931     j += sqlite3VdbeSerialPut(&zNewRecord[j], pRec, serial_type); /* content */
2932   }while( (++pRec)<=pLast );
2933   assert( i==nHdr );
2934   assert( j==nByte );
2935 
2936   assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
2937   pOut->n = (int)nByte;
2938   pOut->flags = MEM_Blob;
2939   if( nZero ){
2940     pOut->u.nZero = nZero;
2941     pOut->flags |= MEM_Zero;
2942   }
2943   REGISTER_TRACE(pOp->p3, pOut);
2944   UPDATE_MAX_BLOBSIZE(pOut);
2945   break;
2946 }
2947 
2948 /* Opcode: Count P1 P2 * * *
2949 ** Synopsis: r[P2]=count()
2950 **
2951 ** Store the number of entries (an integer value) in the table or index
2952 ** opened by cursor P1 in register P2
2953 */
2954 #ifndef SQLITE_OMIT_BTREECOUNT
2955 case OP_Count: {         /* out2 */
2956   i64 nEntry;
2957   BtCursor *pCrsr;
2958 
2959   assert( p->apCsr[pOp->p1]->eCurType==CURTYPE_BTREE );
2960   pCrsr = p->apCsr[pOp->p1]->uc.pCursor;
2961   assert( pCrsr );
2962   nEntry = 0;  /* Not needed.  Only used to silence a warning. */
2963   rc = sqlite3BtreeCount(pCrsr, &nEntry);
2964   if( rc ) goto abort_due_to_error;
2965   pOut = out2Prerelease(p, pOp);
2966   pOut->u.i = nEntry;
2967   break;
2968 }
2969 #endif
2970 
2971 /* Opcode: Savepoint P1 * * P4 *
2972 **
2973 ** Open, release or rollback the savepoint named by parameter P4, depending
2974 ** on the value of P1. To open a new savepoint, P1==0. To release (commit) an
2975 ** existing savepoint, P1==1, or to rollback an existing savepoint P1==2.
2976 */
2977 case OP_Savepoint: {
2978   int p1;                         /* Value of P1 operand */
2979   char *zName;                    /* Name of savepoint */
2980   int nName;
2981   Savepoint *pNew;
2982   Savepoint *pSavepoint;
2983   Savepoint *pTmp;
2984   int iSavepoint;
2985   int ii;
2986 
2987   p1 = pOp->p1;
2988   zName = pOp->p4.z;
2989 
2990   /* Assert that the p1 parameter is valid. Also that if there is no open
2991   ** transaction, then there cannot be any savepoints.
2992   */
2993   assert( db->pSavepoint==0 || db->autoCommit==0 );
2994   assert( p1==SAVEPOINT_BEGIN||p1==SAVEPOINT_RELEASE||p1==SAVEPOINT_ROLLBACK );
2995   assert( db->pSavepoint || db->isTransactionSavepoint==0 );
2996   assert( checkSavepointCount(db) );
2997   assert( p->bIsReader );
2998 
2999   if( p1==SAVEPOINT_BEGIN ){
3000     if( db->nVdbeWrite>0 ){
3001       /* A new savepoint cannot be created if there are active write
3002       ** statements (i.e. open read/write incremental blob handles).
3003       */
3004       sqlite3VdbeError(p, "cannot open savepoint - SQL statements in progress");
3005       rc = SQLITE_BUSY;
3006     }else{
3007       nName = sqlite3Strlen30(zName);
3008 
3009 #ifndef SQLITE_OMIT_VIRTUALTABLE
3010       /* This call is Ok even if this savepoint is actually a transaction
3011       ** savepoint (and therefore should not prompt xSavepoint()) callbacks.
3012       ** If this is a transaction savepoint being opened, it is guaranteed
3013       ** that the db->aVTrans[] array is empty.  */
3014       assert( db->autoCommit==0 || db->nVTrans==0 );
3015       rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN,
3016                                 db->nStatement+db->nSavepoint);
3017       if( rc!=SQLITE_OK ) goto abort_due_to_error;
3018 #endif
3019 
3020       /* Create a new savepoint structure. */
3021       pNew = sqlite3DbMallocRawNN(db, sizeof(Savepoint)+nName+1);
3022       if( pNew ){
3023         pNew->zName = (char *)&pNew[1];
3024         memcpy(pNew->zName, zName, nName+1);
3025 
3026         /* If there is no open transaction, then mark this as a special
3027         ** "transaction savepoint". */
3028         if( db->autoCommit ){
3029           db->autoCommit = 0;
3030           db->isTransactionSavepoint = 1;
3031         }else{
3032           db->nSavepoint++;
3033         }
3034 
3035         /* Link the new savepoint into the database handle's list. */
3036         pNew->pNext = db->pSavepoint;
3037         db->pSavepoint = pNew;
3038         pNew->nDeferredCons = db->nDeferredCons;
3039         pNew->nDeferredImmCons = db->nDeferredImmCons;
3040       }
3041     }
3042   }else{
3043     iSavepoint = 0;
3044 
3045     /* Find the named savepoint. If there is no such savepoint, then an
3046     ** an error is returned to the user.  */
3047     for(
3048       pSavepoint = db->pSavepoint;
3049       pSavepoint && sqlite3StrICmp(pSavepoint->zName, zName);
3050       pSavepoint = pSavepoint->pNext
3051     ){
3052       iSavepoint++;
3053     }
3054     if( !pSavepoint ){
3055       sqlite3VdbeError(p, "no such savepoint: %s", zName);
3056       rc = SQLITE_ERROR;
3057     }else if( db->nVdbeWrite>0 && p1==SAVEPOINT_RELEASE ){
3058       /* It is not possible to release (commit) a savepoint if there are
3059       ** active write statements.
3060       */
3061       sqlite3VdbeError(p, "cannot release savepoint - "
3062                           "SQL statements in progress");
3063       rc = SQLITE_BUSY;
3064     }else{
3065 
3066       /* Determine whether or not this is a transaction savepoint. If so,
3067       ** and this is a RELEASE command, then the current transaction
3068       ** is committed.
3069       */
3070       int isTransaction = pSavepoint->pNext==0 && db->isTransactionSavepoint;
3071       if( isTransaction && p1==SAVEPOINT_RELEASE ){
3072         if( (rc = sqlite3VdbeCheckFk(p, 1))!=SQLITE_OK ){
3073           goto vdbe_return;
3074         }
3075         db->autoCommit = 1;
3076         if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
3077           p->pc = (int)(pOp - aOp);
3078           db->autoCommit = 0;
3079           p->rc = rc = SQLITE_BUSY;
3080           goto vdbe_return;
3081         }
3082         db->isTransactionSavepoint = 0;
3083         rc = p->rc;
3084       }else{
3085         int isSchemaChange;
3086         iSavepoint = db->nSavepoint - iSavepoint - 1;
3087         if( p1==SAVEPOINT_ROLLBACK ){
3088           isSchemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0;
3089           for(ii=0; ii<db->nDb; ii++){
3090             rc = sqlite3BtreeTripAllCursors(db->aDb[ii].pBt,
3091                                        SQLITE_ABORT_ROLLBACK,
3092                                        isSchemaChange==0);
3093             if( rc!=SQLITE_OK ) goto abort_due_to_error;
3094           }
3095         }else{
3096           isSchemaChange = 0;
3097         }
3098         for(ii=0; ii<db->nDb; ii++){
3099           rc = sqlite3BtreeSavepoint(db->aDb[ii].pBt, p1, iSavepoint);
3100           if( rc!=SQLITE_OK ){
3101             goto abort_due_to_error;
3102           }
3103         }
3104         if( isSchemaChange ){
3105           sqlite3ExpirePreparedStatements(db, 0);
3106           sqlite3ResetAllSchemasOfConnection(db);
3107           db->mDbFlags |= DBFLAG_SchemaChange;
3108         }
3109       }
3110 
3111       /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all
3112       ** savepoints nested inside of the savepoint being operated on. */
3113       while( db->pSavepoint!=pSavepoint ){
3114         pTmp = db->pSavepoint;
3115         db->pSavepoint = pTmp->pNext;
3116         sqlite3DbFree(db, pTmp);
3117         db->nSavepoint--;
3118       }
3119 
3120       /* If it is a RELEASE, then destroy the savepoint being operated on
3121       ** too. If it is a ROLLBACK TO, then set the number of deferred
3122       ** constraint violations present in the database to the value stored
3123       ** when the savepoint was created.  */
3124       if( p1==SAVEPOINT_RELEASE ){
3125         assert( pSavepoint==db->pSavepoint );
3126         db->pSavepoint = pSavepoint->pNext;
3127         sqlite3DbFree(db, pSavepoint);
3128         if( !isTransaction ){
3129           db->nSavepoint--;
3130         }
3131       }else{
3132         db->nDeferredCons = pSavepoint->nDeferredCons;
3133         db->nDeferredImmCons = pSavepoint->nDeferredImmCons;
3134       }
3135 
3136       if( !isTransaction || p1==SAVEPOINT_ROLLBACK ){
3137         rc = sqlite3VtabSavepoint(db, p1, iSavepoint);
3138         if( rc!=SQLITE_OK ) goto abort_due_to_error;
3139       }
3140     }
3141   }
3142   if( rc ) goto abort_due_to_error;
3143 
3144   break;
3145 }
3146 
3147 /* Opcode: AutoCommit P1 P2 * * *
3148 **
3149 ** Set the database auto-commit flag to P1 (1 or 0). If P2 is true, roll
3150 ** back any currently active btree transactions. If there are any active
3151 ** VMs (apart from this one), then a ROLLBACK fails.  A COMMIT fails if
3152 ** there are active writing VMs or active VMs that use shared cache.
3153 **
3154 ** This instruction causes the VM to halt.
3155 */
3156 case OP_AutoCommit: {
3157   int desiredAutoCommit;
3158   int iRollback;
3159 
3160   desiredAutoCommit = pOp->p1;
3161   iRollback = pOp->p2;
3162   assert( desiredAutoCommit==1 || desiredAutoCommit==0 );
3163   assert( desiredAutoCommit==1 || iRollback==0 );
3164   assert( db->nVdbeActive>0 );  /* At least this one VM is active */
3165   assert( p->bIsReader );
3166 
3167   if( desiredAutoCommit!=db->autoCommit ){
3168     if( iRollback ){
3169       assert( desiredAutoCommit==1 );
3170       sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
3171       db->autoCommit = 1;
3172     }else if( desiredAutoCommit && db->nVdbeWrite>0 ){
3173       /* If this instruction implements a COMMIT and other VMs are writing
3174       ** return an error indicating that the other VMs must complete first.
3175       */
3176       sqlite3VdbeError(p, "cannot commit transaction - "
3177                           "SQL statements in progress");
3178       rc = SQLITE_BUSY;
3179       goto abort_due_to_error;
3180     }else if( (rc = sqlite3VdbeCheckFk(p, 1))!=SQLITE_OK ){
3181       goto vdbe_return;
3182     }else{
3183       db->autoCommit = (u8)desiredAutoCommit;
3184     }
3185     if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
3186       p->pc = (int)(pOp - aOp);
3187       db->autoCommit = (u8)(1-desiredAutoCommit);
3188       p->rc = rc = SQLITE_BUSY;
3189       goto vdbe_return;
3190     }
3191     assert( db->nStatement==0 );
3192     sqlite3CloseSavepoints(db);
3193     if( p->rc==SQLITE_OK ){
3194       rc = SQLITE_DONE;
3195     }else{
3196       rc = SQLITE_ERROR;
3197     }
3198     goto vdbe_return;
3199   }else{
3200     sqlite3VdbeError(p,
3201         (!desiredAutoCommit)?"cannot start a transaction within a transaction":(
3202         (iRollback)?"cannot rollback - no transaction is active":
3203                    "cannot commit - no transaction is active"));
3204 
3205     rc = SQLITE_ERROR;
3206     goto abort_due_to_error;
3207   }
3208   break;
3209 }
3210 
3211 /* Opcode: Transaction P1 P2 P3 P4 P5
3212 **
3213 ** Begin a transaction on database P1 if a transaction is not already
3214 ** active.
3215 ** If P2 is non-zero, then a write-transaction is started, or if a
3216 ** read-transaction is already active, it is upgraded to a write-transaction.
3217 ** If P2 is zero, then a read-transaction is started.
3218 **
3219 ** P1 is the index of the database file on which the transaction is
3220 ** started.  Index 0 is the main database file and index 1 is the
3221 ** file used for temporary tables.  Indices of 2 or more are used for
3222 ** attached databases.
3223 **
3224 ** If a write-transaction is started and the Vdbe.usesStmtJournal flag is
3225 ** true (this flag is set if the Vdbe may modify more than one row and may
3226 ** throw an ABORT exception), a statement transaction may also be opened.
3227 ** More specifically, a statement transaction is opened iff the database
3228 ** connection is currently not in autocommit mode, or if there are other
3229 ** active statements. A statement transaction allows the changes made by this
3230 ** VDBE to be rolled back after an error without having to roll back the
3231 ** entire transaction. If no error is encountered, the statement transaction
3232 ** will automatically commit when the VDBE halts.
3233 **
3234 ** If P5!=0 then this opcode also checks the schema cookie against P3
3235 ** and the schema generation counter against P4.
3236 ** The cookie changes its value whenever the database schema changes.
3237 ** This operation is used to detect when that the cookie has changed
3238 ** and that the current process needs to reread the schema.  If the schema
3239 ** cookie in P3 differs from the schema cookie in the database header or
3240 ** if the schema generation counter in P4 differs from the current
3241 ** generation counter, then an SQLITE_SCHEMA error is raised and execution
3242 ** halts.  The sqlite3_step() wrapper function might then reprepare the
3243 ** statement and rerun it from the beginning.
3244 */
3245 case OP_Transaction: {
3246   Btree *pBt;
3247   int iMeta = 0;
3248 
3249   assert( p->bIsReader );
3250   assert( p->readOnly==0 || pOp->p2==0 );
3251   assert( pOp->p1>=0 && pOp->p1<db->nDb );
3252   assert( DbMaskTest(p->btreeMask, pOp->p1) );
3253   if( pOp->p2 && (db->flags & SQLITE_QueryOnly)!=0 ){
3254     rc = SQLITE_READONLY;
3255     goto abort_due_to_error;
3256   }
3257   pBt = db->aDb[pOp->p1].pBt;
3258 
3259   if( pBt ){
3260     rc = sqlite3BtreeBeginTrans(pBt, pOp->p2, &iMeta);
3261     testcase( rc==SQLITE_BUSY_SNAPSHOT );
3262     testcase( rc==SQLITE_BUSY_RECOVERY );
3263     if( rc!=SQLITE_OK ){
3264       if( (rc&0xff)==SQLITE_BUSY ){
3265         p->pc = (int)(pOp - aOp);
3266         p->rc = rc;
3267         goto vdbe_return;
3268       }
3269       goto abort_due_to_error;
3270     }
3271 
3272     if( pOp->p2 && p->usesStmtJournal
3273      && (db->autoCommit==0 || db->nVdbeRead>1)
3274     ){
3275       assert( sqlite3BtreeIsInTrans(pBt) );
3276       if( p->iStatement==0 ){
3277         assert( db->nStatement>=0 && db->nSavepoint>=0 );
3278         db->nStatement++;
3279         p->iStatement = db->nSavepoint + db->nStatement;
3280       }
3281 
3282       rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN, p->iStatement-1);
3283       if( rc==SQLITE_OK ){
3284         rc = sqlite3BtreeBeginStmt(pBt, p->iStatement);
3285       }
3286 
3287       /* Store the current value of the database handles deferred constraint
3288       ** counter. If the statement transaction needs to be rolled back,
3289       ** the value of this counter needs to be restored too.  */
3290       p->nStmtDefCons = db->nDeferredCons;
3291       p->nStmtDefImmCons = db->nDeferredImmCons;
3292     }
3293   }
3294   assert( pOp->p5==0 || pOp->p4type==P4_INT32 );
3295   if( pOp->p5
3296    && (iMeta!=pOp->p3
3297       || db->aDb[pOp->p1].pSchema->iGeneration!=pOp->p4.i)
3298   ){
3299     /*
3300     ** IMPLEMENTATION-OF: R-03189-51135 As each SQL statement runs, the schema
3301     ** version is checked to ensure that the schema has not changed since the
3302     ** SQL statement was prepared.
3303     */
3304     sqlite3DbFree(db, p->zErrMsg);
3305     p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
3306     /* If the schema-cookie from the database file matches the cookie
3307     ** stored with the in-memory representation of the schema, do
3308     ** not reload the schema from the database file.
3309     **
3310     ** If virtual-tables are in use, this is not just an optimization.
3311     ** Often, v-tables store their data in other SQLite tables, which
3312     ** are queried from within xNext() and other v-table methods using
3313     ** prepared queries. If such a query is out-of-date, we do not want to
3314     ** discard the database schema, as the user code implementing the
3315     ** v-table would have to be ready for the sqlite3_vtab structure itself
3316     ** to be invalidated whenever sqlite3_step() is called from within
3317     ** a v-table method.
3318     */
3319     if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
3320       sqlite3ResetOneSchema(db, pOp->p1);
3321     }
3322     p->expired = 1;
3323     rc = SQLITE_SCHEMA;
3324   }
3325   if( rc ) goto abort_due_to_error;
3326   break;
3327 }
3328 
3329 /* Opcode: ReadCookie P1 P2 P3 * *
3330 **
3331 ** Read cookie number P3 from database P1 and write it into register P2.
3332 ** P3==1 is the schema version.  P3==2 is the database format.
3333 ** P3==3 is the recommended pager cache size, and so forth.  P1==0 is
3334 ** the main database file and P1==1 is the database file used to store
3335 ** temporary tables.
3336 **
3337 ** There must be a read-lock on the database (either a transaction
3338 ** must be started or there must be an open cursor) before
3339 ** executing this instruction.
3340 */
3341 case OP_ReadCookie: {               /* out2 */
3342   int iMeta;
3343   int iDb;
3344   int iCookie;
3345 
3346   assert( p->bIsReader );
3347   iDb = pOp->p1;
3348   iCookie = pOp->p3;
3349   assert( pOp->p3<SQLITE_N_BTREE_META );
3350   assert( iDb>=0 && iDb<db->nDb );
3351   assert( db->aDb[iDb].pBt!=0 );
3352   assert( DbMaskTest(p->btreeMask, iDb) );
3353 
3354   sqlite3BtreeGetMeta(db->aDb[iDb].pBt, iCookie, (u32 *)&iMeta);
3355   pOut = out2Prerelease(p, pOp);
3356   pOut->u.i = iMeta;
3357   break;
3358 }
3359 
3360 /* Opcode: SetCookie P1 P2 P3 * *
3361 **
3362 ** Write the integer value P3 into cookie number P2 of database P1.
3363 ** P2==1 is the schema version.  P2==2 is the database format.
3364 ** P2==3 is the recommended pager cache
3365 ** size, and so forth.  P1==0 is the main database file and P1==1 is the
3366 ** database file used to store temporary tables.
3367 **
3368 ** A transaction must be started before executing this opcode.
3369 */
3370 case OP_SetCookie: {
3371   Db *pDb;
3372 
3373   sqlite3VdbeIncrWriteCounter(p, 0);
3374   assert( pOp->p2<SQLITE_N_BTREE_META );
3375   assert( pOp->p1>=0 && pOp->p1<db->nDb );
3376   assert( DbMaskTest(p->btreeMask, pOp->p1) );
3377   assert( p->readOnly==0 );
3378   pDb = &db->aDb[pOp->p1];
3379   assert( pDb->pBt!=0 );
3380   assert( sqlite3SchemaMutexHeld(db, pOp->p1, 0) );
3381   /* See note about index shifting on OP_ReadCookie */
3382   rc = sqlite3BtreeUpdateMeta(pDb->pBt, pOp->p2, pOp->p3);
3383   if( pOp->p2==BTREE_SCHEMA_VERSION ){
3384     /* When the schema cookie changes, record the new cookie internally */
3385     pDb->pSchema->schema_cookie = pOp->p3;
3386     db->mDbFlags |= DBFLAG_SchemaChange;
3387   }else if( pOp->p2==BTREE_FILE_FORMAT ){
3388     /* Record changes in the file format */
3389     pDb->pSchema->file_format = pOp->p3;
3390   }
3391   if( pOp->p1==1 ){
3392     /* Invalidate all prepared statements whenever the TEMP database
3393     ** schema is changed.  Ticket #1644 */
3394     sqlite3ExpirePreparedStatements(db, 0);
3395     p->expired = 0;
3396   }
3397   if( rc ) goto abort_due_to_error;
3398   break;
3399 }
3400 
3401 /* Opcode: OpenRead P1 P2 P3 P4 P5
3402 ** Synopsis: root=P2 iDb=P3
3403 **
3404 ** Open a read-only cursor for the database table whose root page is
3405 ** P2 in a database file.  The database file is determined by P3.
3406 ** P3==0 means the main database, P3==1 means the database used for
3407 ** temporary tables, and P3>1 means used the corresponding attached
3408 ** database.  Give the new cursor an identifier of P1.  The P1
3409 ** values need not be contiguous but all P1 values should be small integers.
3410 ** It is an error for P1 to be negative.
3411 **
3412 ** Allowed P5 bits:
3413 ** <ul>
3414 ** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
3415 **       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
3416 **       of OP_SeekLE/OP_IdxGT)
3417 ** </ul>
3418 **
3419 ** The P4 value may be either an integer (P4_INT32) or a pointer to
3420 ** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo
3421 ** object, then table being opened must be an [index b-tree] where the
3422 ** KeyInfo object defines the content and collating
3423 ** sequence of that index b-tree. Otherwise, if P4 is an integer
3424 ** value, then the table being opened must be a [table b-tree] with a
3425 ** number of columns no less than the value of P4.
3426 **
3427 ** See also: OpenWrite, ReopenIdx
3428 */
3429 /* Opcode: ReopenIdx P1 P2 P3 P4 P5
3430 ** Synopsis: root=P2 iDb=P3
3431 **
3432 ** The ReopenIdx opcode works like OP_OpenRead except that it first
3433 ** checks to see if the cursor on P1 is already open on the same
3434 ** b-tree and if it is this opcode becomes a no-op.  In other words,
3435 ** if the cursor is already open, do not reopen it.
3436 **
3437 ** The ReopenIdx opcode may only be used with P5==0 or P5==OPFLAG_SEEKEQ
3438 ** and with P4 being a P4_KEYINFO object.  Furthermore, the P3 value must
3439 ** be the same as every other ReopenIdx or OpenRead for the same cursor
3440 ** number.
3441 **
3442 ** Allowed P5 bits:
3443 ** <ul>
3444 ** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
3445 **       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
3446 **       of OP_SeekLE/OP_IdxGT)
3447 ** </ul>
3448 **
3449 ** See also: OP_OpenRead, OP_OpenWrite
3450 */
3451 /* Opcode: OpenWrite P1 P2 P3 P4 P5
3452 ** Synopsis: root=P2 iDb=P3
3453 **
3454 ** Open a read/write cursor named P1 on the table or index whose root
3455 ** page is P2 (or whose root page is held in register P2 if the
3456 ** OPFLAG_P2ISREG bit is set in P5 - see below).
3457 **
3458 ** The P4 value may be either an integer (P4_INT32) or a pointer to
3459 ** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo
3460 ** object, then table being opened must be an [index b-tree] where the
3461 ** KeyInfo object defines the content and collating
3462 ** sequence of that index b-tree. Otherwise, if P4 is an integer
3463 ** value, then the table being opened must be a [table b-tree] with a
3464 ** number of columns no less than the value of P4.
3465 **
3466 ** Allowed P5 bits:
3467 ** <ul>
3468 ** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
3469 **       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
3470 **       of OP_SeekLE/OP_IdxGT)
3471 ** <li>  <b>0x08 OPFLAG_FORDELETE</b>: This cursor is used only to seek
3472 **       and subsequently delete entries in an index btree.  This is a
3473 **       hint to the storage engine that the storage engine is allowed to
3474 **       ignore.  The hint is not used by the official SQLite b*tree storage
3475 **       engine, but is used by COMDB2.
3476 ** <li>  <b>0x10 OPFLAG_P2ISREG</b>: Use the content of register P2
3477 **       as the root page, not the value of P2 itself.
3478 ** </ul>
3479 **
3480 ** This instruction works like OpenRead except that it opens the cursor
3481 ** in read/write mode.
3482 **
3483 ** See also: OP_OpenRead, OP_ReopenIdx
3484 */
3485 case OP_ReopenIdx: {
3486   int nField;
3487   KeyInfo *pKeyInfo;
3488   int p2;
3489   int iDb;
3490   int wrFlag;
3491   Btree *pX;
3492   VdbeCursor *pCur;
3493   Db *pDb;
3494 
3495   assert( pOp->p5==0 || pOp->p5==OPFLAG_SEEKEQ );
3496   assert( pOp->p4type==P4_KEYINFO );
3497   pCur = p->apCsr[pOp->p1];
3498   if( pCur && pCur->pgnoRoot==(u32)pOp->p2 ){
3499     assert( pCur->iDb==pOp->p3 );      /* Guaranteed by the code generator */
3500     goto open_cursor_set_hints;
3501   }
3502   /* If the cursor is not currently open or is open on a different
3503   ** index, then fall through into OP_OpenRead to force a reopen */
3504 case OP_OpenRead:
3505 case OP_OpenWrite:
3506 
3507   assert( pOp->opcode==OP_OpenWrite || pOp->p5==0 || pOp->p5==OPFLAG_SEEKEQ );
3508   assert( p->bIsReader );
3509   assert( pOp->opcode==OP_OpenRead || pOp->opcode==OP_ReopenIdx
3510           || p->readOnly==0 );
3511 
3512   if( p->expired==1 ){
3513     rc = SQLITE_ABORT_ROLLBACK;
3514     goto abort_due_to_error;
3515   }
3516 
3517   nField = 0;
3518   pKeyInfo = 0;
3519   p2 = pOp->p2;
3520   iDb = pOp->p3;
3521   assert( iDb>=0 && iDb<db->nDb );
3522   assert( DbMaskTest(p->btreeMask, iDb) );
3523   pDb = &db->aDb[iDb];
3524   pX = pDb->pBt;
3525   assert( pX!=0 );
3526   if( pOp->opcode==OP_OpenWrite ){
3527     assert( OPFLAG_FORDELETE==BTREE_FORDELETE );
3528     wrFlag = BTREE_WRCSR | (pOp->p5 & OPFLAG_FORDELETE);
3529     assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
3530     if( pDb->pSchema->file_format < p->minWriteFileFormat ){
3531       p->minWriteFileFormat = pDb->pSchema->file_format;
3532     }
3533   }else{
3534     wrFlag = 0;
3535   }
3536   if( pOp->p5 & OPFLAG_P2ISREG ){
3537     assert( p2>0 );
3538     assert( p2<=(p->nMem+1 - p->nCursor) );
3539     assert( pOp->opcode==OP_OpenWrite );
3540     pIn2 = &aMem[p2];
3541     assert( memIsValid(pIn2) );
3542     assert( (pIn2->flags & MEM_Int)!=0 );
3543     sqlite3VdbeMemIntegerify(pIn2);
3544     p2 = (int)pIn2->u.i;
3545     /* The p2 value always comes from a prior OP_CreateBtree opcode and
3546     ** that opcode will always set the p2 value to 2 or more or else fail.
3547     ** If there were a failure, the prepared statement would have halted
3548     ** before reaching this instruction. */
3549     assert( p2>=2 );
3550   }
3551   if( pOp->p4type==P4_KEYINFO ){
3552     pKeyInfo = pOp->p4.pKeyInfo;
3553     assert( pKeyInfo->enc==ENC(db) );
3554     assert( pKeyInfo->db==db );
3555     nField = pKeyInfo->nAllField;
3556   }else if( pOp->p4type==P4_INT32 ){
3557     nField = pOp->p4.i;
3558   }
3559   assert( pOp->p1>=0 );
3560   assert( nField>=0 );
3561   testcase( nField==0 );  /* Table with INTEGER PRIMARY KEY and nothing else */
3562   pCur = allocateCursor(p, pOp->p1, nField, iDb, CURTYPE_BTREE);
3563   if( pCur==0 ) goto no_mem;
3564   pCur->nullRow = 1;
3565   pCur->isOrdered = 1;
3566   pCur->pgnoRoot = p2;
3567 #ifdef SQLITE_DEBUG
3568   pCur->wrFlag = wrFlag;
3569 #endif
3570   rc = sqlite3BtreeCursor(pX, p2, wrFlag, pKeyInfo, pCur->uc.pCursor);
3571   pCur->pKeyInfo = pKeyInfo;
3572   /* Set the VdbeCursor.isTable variable. Previous versions of
3573   ** SQLite used to check if the root-page flags were sane at this point
3574   ** and report database corruption if they were not, but this check has
3575   ** since moved into the btree layer.  */
3576   pCur->isTable = pOp->p4type!=P4_KEYINFO;
3577 
3578 open_cursor_set_hints:
3579   assert( OPFLAG_BULKCSR==BTREE_BULKLOAD );
3580   assert( OPFLAG_SEEKEQ==BTREE_SEEK_EQ );
3581   testcase( pOp->p5 & OPFLAG_BULKCSR );
3582 #ifdef SQLITE_ENABLE_CURSOR_HINTS
3583   testcase( pOp->p2 & OPFLAG_SEEKEQ );
3584 #endif
3585   sqlite3BtreeCursorHintFlags(pCur->uc.pCursor,
3586                                (pOp->p5 & (OPFLAG_BULKCSR|OPFLAG_SEEKEQ)));
3587   if( rc ) goto abort_due_to_error;
3588   break;
3589 }
3590 
3591 /* Opcode: OpenDup P1 P2 * * *
3592 **
3593 ** Open a new cursor P1 that points to the same ephemeral table as
3594 ** cursor P2.  The P2 cursor must have been opened by a prior OP_OpenEphemeral
3595 ** opcode.  Only ephemeral cursors may be duplicated.
3596 **
3597 ** Duplicate ephemeral cursors are used for self-joins of materialized views.
3598 */
3599 case OP_OpenDup: {
3600   VdbeCursor *pOrig;    /* The original cursor to be duplicated */
3601   VdbeCursor *pCx;      /* The new cursor */
3602 
3603   pOrig = p->apCsr[pOp->p2];
3604   assert( pOrig->pBtx!=0 );  /* Only ephemeral cursors can be duplicated */
3605 
3606   pCx = allocateCursor(p, pOp->p1, pOrig->nField, -1, CURTYPE_BTREE);
3607   if( pCx==0 ) goto no_mem;
3608   pCx->nullRow = 1;
3609   pCx->isEphemeral = 1;
3610   pCx->pKeyInfo = pOrig->pKeyInfo;
3611   pCx->isTable = pOrig->isTable;
3612   rc = sqlite3BtreeCursor(pOrig->pBtx, MASTER_ROOT, BTREE_WRCSR,
3613                           pCx->pKeyInfo, pCx->uc.pCursor);
3614   /* The sqlite3BtreeCursor() routine can only fail for the first cursor
3615   ** opened for a database.  Since there is already an open cursor when this
3616   ** opcode is run, the sqlite3BtreeCursor() cannot fail */
3617   assert( rc==SQLITE_OK );
3618   break;
3619 }
3620 
3621 
3622 /* Opcode: OpenEphemeral P1 P2 * P4 P5
3623 ** Synopsis: nColumn=P2
3624 **
3625 ** Open a new cursor P1 to a transient table.
3626 ** The cursor is always opened read/write even if
3627 ** the main database is read-only.  The ephemeral
3628 ** table is deleted automatically when the cursor is closed.
3629 **
3630 ** P2 is the number of columns in the ephemeral table.
3631 ** The cursor points to a BTree table if P4==0 and to a BTree index
3632 ** if P4 is not 0.  If P4 is not NULL, it points to a KeyInfo structure
3633 ** that defines the format of keys in the index.
3634 **
3635 ** The P5 parameter can be a mask of the BTREE_* flags defined
3636 ** in btree.h.  These flags control aspects of the operation of
3637 ** the btree.  The BTREE_OMIT_JOURNAL and BTREE_SINGLE flags are
3638 ** added automatically.
3639 */
3640 /* Opcode: OpenAutoindex P1 P2 * P4 *
3641 ** Synopsis: nColumn=P2
3642 **
3643 ** This opcode works the same as OP_OpenEphemeral.  It has a
3644 ** different name to distinguish its use.  Tables created using
3645 ** by this opcode will be used for automatically created transient
3646 ** indices in joins.
3647 */
3648 case OP_OpenAutoindex:
3649 case OP_OpenEphemeral: {
3650   VdbeCursor *pCx;
3651   KeyInfo *pKeyInfo;
3652 
3653   static const int vfsFlags =
3654       SQLITE_OPEN_READWRITE |
3655       SQLITE_OPEN_CREATE |
3656       SQLITE_OPEN_EXCLUSIVE |
3657       SQLITE_OPEN_DELETEONCLOSE |
3658       SQLITE_OPEN_TRANSIENT_DB;
3659   assert( pOp->p1>=0 );
3660   assert( pOp->p2>=0 );
3661   pCx = allocateCursor(p, pOp->p1, pOp->p2, -1, CURTYPE_BTREE);
3662   if( pCx==0 ) goto no_mem;
3663   pCx->nullRow = 1;
3664   pCx->isEphemeral = 1;
3665   rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pCx->pBtx,
3666                         BTREE_OMIT_JOURNAL | BTREE_SINGLE | pOp->p5, vfsFlags);
3667   if( rc==SQLITE_OK ){
3668     rc = sqlite3BtreeBeginTrans(pCx->pBtx, 1, 0);
3669   }
3670   if( rc==SQLITE_OK ){
3671     /* If a transient index is required, create it by calling
3672     ** sqlite3BtreeCreateTable() with the BTREE_BLOBKEY flag before
3673     ** opening it. If a transient table is required, just use the
3674     ** automatically created table with root-page 1 (an BLOB_INTKEY table).
3675     */
3676     if( (pCx->pKeyInfo = pKeyInfo = pOp->p4.pKeyInfo)!=0 ){
3677       int pgno;
3678       assert( pOp->p4type==P4_KEYINFO );
3679       rc = sqlite3BtreeCreateTable(pCx->pBtx, &pgno, BTREE_BLOBKEY | pOp->p5);
3680       if( rc==SQLITE_OK ){
3681         assert( pgno==MASTER_ROOT+1 );
3682         assert( pKeyInfo->db==db );
3683         assert( pKeyInfo->enc==ENC(db) );
3684         rc = sqlite3BtreeCursor(pCx->pBtx, pgno, BTREE_WRCSR,
3685                                 pKeyInfo, pCx->uc.pCursor);
3686       }
3687       pCx->isTable = 0;
3688     }else{
3689       rc = sqlite3BtreeCursor(pCx->pBtx, MASTER_ROOT, BTREE_WRCSR,
3690                               0, pCx->uc.pCursor);
3691       pCx->isTable = 1;
3692     }
3693   }
3694   if( rc ) goto abort_due_to_error;
3695   pCx->isOrdered = (pOp->p5!=BTREE_UNORDERED);
3696   break;
3697 }
3698 
3699 /* Opcode: SorterOpen P1 P2 P3 P4 *
3700 **
3701 ** This opcode works like OP_OpenEphemeral except that it opens
3702 ** a transient index that is specifically designed to sort large
3703 ** tables using an external merge-sort algorithm.
3704 **
3705 ** If argument P3 is non-zero, then it indicates that the sorter may
3706 ** assume that a stable sort considering the first P3 fields of each
3707 ** key is sufficient to produce the required results.
3708 */
3709 case OP_SorterOpen: {
3710   VdbeCursor *pCx;
3711 
3712   assert( pOp->p1>=0 );
3713   assert( pOp->p2>=0 );
3714   pCx = allocateCursor(p, pOp->p1, pOp->p2, -1, CURTYPE_SORTER);
3715   if( pCx==0 ) goto no_mem;
3716   pCx->pKeyInfo = pOp->p4.pKeyInfo;
3717   assert( pCx->pKeyInfo->db==db );
3718   assert( pCx->pKeyInfo->enc==ENC(db) );
3719   rc = sqlite3VdbeSorterInit(db, pOp->p3, pCx);
3720   if( rc ) goto abort_due_to_error;
3721   break;
3722 }
3723 
3724 /* Opcode: SequenceTest P1 P2 * * *
3725 ** Synopsis: if( cursor[P1].ctr++ ) pc = P2
3726 **
3727 ** P1 is a sorter cursor. If the sequence counter is currently zero, jump
3728 ** to P2. Regardless of whether or not the jump is taken, increment the
3729 ** the sequence value.
3730 */
3731 case OP_SequenceTest: {
3732   VdbeCursor *pC;
3733   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
3734   pC = p->apCsr[pOp->p1];
3735   assert( isSorter(pC) );
3736   if( (pC->seqCount++)==0 ){
3737     goto jump_to_p2;
3738   }
3739   break;
3740 }
3741 
3742 /* Opcode: OpenPseudo P1 P2 P3 * *
3743 ** Synopsis: P3 columns in r[P2]
3744 **
3745 ** Open a new cursor that points to a fake table that contains a single
3746 ** row of data.  The content of that one row is the content of memory
3747 ** register P2.  In other words, cursor P1 becomes an alias for the
3748 ** MEM_Blob content contained in register P2.
3749 **
3750 ** A pseudo-table created by this opcode is used to hold a single
3751 ** row output from the sorter so that the row can be decomposed into
3752 ** individual columns using the OP_Column opcode.  The OP_Column opcode
3753 ** is the only cursor opcode that works with a pseudo-table.
3754 **
3755 ** P3 is the number of fields in the records that will be stored by
3756 ** the pseudo-table.
3757 */
3758 case OP_OpenPseudo: {
3759   VdbeCursor *pCx;
3760 
3761   assert( pOp->p1>=0 );
3762   assert( pOp->p3>=0 );
3763   pCx = allocateCursor(p, pOp->p1, pOp->p3, -1, CURTYPE_PSEUDO);
3764   if( pCx==0 ) goto no_mem;
3765   pCx->nullRow = 1;
3766   pCx->seekResult = pOp->p2;
3767   pCx->isTable = 1;
3768   /* Give this pseudo-cursor a fake BtCursor pointer so that pCx
3769   ** can be safely passed to sqlite3VdbeCursorMoveto().  This avoids a test
3770   ** for pCx->eCurType==CURTYPE_BTREE inside of sqlite3VdbeCursorMoveto()
3771   ** which is a performance optimization */
3772   pCx->uc.pCursor = sqlite3BtreeFakeValidCursor();
3773   assert( pOp->p5==0 );
3774   break;
3775 }
3776 
3777 /* Opcode: Close P1 * * * *
3778 **
3779 ** Close a cursor previously opened as P1.  If P1 is not
3780 ** currently open, this instruction is a no-op.
3781 */
3782 case OP_Close: {
3783   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
3784   sqlite3VdbeFreeCursor(p, p->apCsr[pOp->p1]);
3785   p->apCsr[pOp->p1] = 0;
3786   break;
3787 }
3788 
3789 #ifdef SQLITE_ENABLE_COLUMN_USED_MASK
3790 /* Opcode: ColumnsUsed P1 * * P4 *
3791 **
3792 ** This opcode (which only exists if SQLite was compiled with
3793 ** SQLITE_ENABLE_COLUMN_USED_MASK) identifies which columns of the
3794 ** table or index for cursor P1 are used.  P4 is a 64-bit integer
3795 ** (P4_INT64) in which the first 63 bits are one for each of the
3796 ** first 63 columns of the table or index that are actually used
3797 ** by the cursor.  The high-order bit is set if any column after
3798 ** the 64th is used.
3799 */
3800 case OP_ColumnsUsed: {
3801   VdbeCursor *pC;
3802   pC = p->apCsr[pOp->p1];
3803   assert( pC->eCurType==CURTYPE_BTREE );
3804   pC->maskUsed = *(u64*)pOp->p4.pI64;
3805   break;
3806 }
3807 #endif
3808 
3809 /* Opcode: SeekGE P1 P2 P3 P4 *
3810 ** Synopsis: key=r[P3@P4]
3811 **
3812 ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
3813 ** use the value in register P3 as the key.  If cursor P1 refers
3814 ** to an SQL index, then P3 is the first in an array of P4 registers
3815 ** that are used as an unpacked index key.
3816 **
3817 ** Reposition cursor P1 so that  it points to the smallest entry that
3818 ** is greater than or equal to the key value. If there are no records
3819 ** greater than or equal to the key and P2 is not zero, then jump to P2.
3820 **
3821 ** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
3822 ** opcode will always land on a record that equally equals the key, or
3823 ** else jump immediately to P2.  When the cursor is OPFLAG_SEEKEQ, this
3824 ** opcode must be followed by an IdxLE opcode with the same arguments.
3825 ** The IdxLE opcode will be skipped if this opcode succeeds, but the
3826 ** IdxLE opcode will be used on subsequent loop iterations.
3827 **
3828 ** This opcode leaves the cursor configured to move in forward order,
3829 ** from the beginning toward the end.  In other words, the cursor is
3830 ** configured to use Next, not Prev.
3831 **
3832 ** See also: Found, NotFound, SeekLt, SeekGt, SeekLe
3833 */
3834 /* Opcode: SeekGT P1 P2 P3 P4 *
3835 ** Synopsis: key=r[P3@P4]
3836 **
3837 ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
3838 ** use the value in register P3 as a key. If cursor P1 refers
3839 ** to an SQL index, then P3 is the first in an array of P4 registers
3840 ** that are used as an unpacked index key.
3841 **
3842 ** Reposition cursor P1 so that  it points to the smallest entry that
3843 ** is greater than the key value. If there are no records greater than
3844 ** the key and P2 is not zero, then jump to P2.
3845 **
3846 ** This opcode leaves the cursor configured to move in forward order,
3847 ** from the beginning toward the end.  In other words, the cursor is
3848 ** configured to use Next, not Prev.
3849 **
3850 ** See also: Found, NotFound, SeekLt, SeekGe, SeekLe
3851 */
3852 /* Opcode: SeekLT P1 P2 P3 P4 *
3853 ** Synopsis: key=r[P3@P4]
3854 **
3855 ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
3856 ** use the value in register P3 as a key. If cursor P1 refers
3857 ** to an SQL index, then P3 is the first in an array of P4 registers
3858 ** that are used as an unpacked index key.
3859 **
3860 ** Reposition cursor P1 so that  it points to the largest entry that
3861 ** is less than the key value. If there are no records less than
3862 ** the key and P2 is not zero, then jump to P2.
3863 **
3864 ** This opcode leaves the cursor configured to move in reverse order,
3865 ** from the end toward the beginning.  In other words, the cursor is
3866 ** configured to use Prev, not Next.
3867 **
3868 ** See also: Found, NotFound, SeekGt, SeekGe, SeekLe
3869 */
3870 /* Opcode: SeekLE P1 P2 P3 P4 *
3871 ** Synopsis: key=r[P3@P4]
3872 **
3873 ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
3874 ** use the value in register P3 as a key. If cursor P1 refers
3875 ** to an SQL index, then P3 is the first in an array of P4 registers
3876 ** that are used as an unpacked index key.
3877 **
3878 ** Reposition cursor P1 so that it points to the largest entry that
3879 ** is less than or equal to the key value. If there are no records
3880 ** less than or equal to the key and P2 is not zero, then jump to P2.
3881 **
3882 ** This opcode leaves the cursor configured to move in reverse order,
3883 ** from the end toward the beginning.  In other words, the cursor is
3884 ** configured to use Prev, not Next.
3885 **
3886 ** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
3887 ** opcode will always land on a record that equally equals the key, or
3888 ** else jump immediately to P2.  When the cursor is OPFLAG_SEEKEQ, this
3889 ** opcode must be followed by an IdxGE opcode with the same arguments.
3890 ** The IdxGE opcode will be skipped if this opcode succeeds, but the
3891 ** IdxGE opcode will be used on subsequent loop iterations.
3892 **
3893 ** See also: Found, NotFound, SeekGt, SeekGe, SeekLt
3894 */
3895 case OP_SeekLT:         /* jump, in3, group */
3896 case OP_SeekLE:         /* jump, in3, group */
3897 case OP_SeekGE:         /* jump, in3, group */
3898 case OP_SeekGT: {       /* jump, in3, group */
3899   int res;           /* Comparison result */
3900   int oc;            /* Opcode */
3901   VdbeCursor *pC;    /* The cursor to seek */
3902   UnpackedRecord r;  /* The key to seek for */
3903   int nField;        /* Number of columns or fields in the key */
3904   i64 iKey;          /* The rowid we are to seek to */
3905   int eqOnly;        /* Only interested in == results */
3906 
3907   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
3908   assert( pOp->p2!=0 );
3909   pC = p->apCsr[pOp->p1];
3910   assert( pC!=0 );
3911   assert( pC->eCurType==CURTYPE_BTREE );
3912   assert( OP_SeekLE == OP_SeekLT+1 );
3913   assert( OP_SeekGE == OP_SeekLT+2 );
3914   assert( OP_SeekGT == OP_SeekLT+3 );
3915   assert( pC->isOrdered );
3916   assert( pC->uc.pCursor!=0 );
3917   oc = pOp->opcode;
3918   eqOnly = 0;
3919   pC->nullRow = 0;
3920 #ifdef SQLITE_DEBUG
3921   pC->seekOp = pOp->opcode;
3922 #endif
3923 
3924   if( pC->isTable ){
3925     /* The BTREE_SEEK_EQ flag is only set on index cursors */
3926     assert( sqlite3BtreeCursorHasHint(pC->uc.pCursor, BTREE_SEEK_EQ)==0
3927               || CORRUPT_DB );
3928 
3929     /* The input value in P3 might be of any type: integer, real, string,
3930     ** blob, or NULL.  But it needs to be an integer before we can do
3931     ** the seek, so convert it. */
3932     pIn3 = &aMem[pOp->p3];
3933     if( (pIn3->flags & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
3934       applyNumericAffinity(pIn3, 0);
3935     }
3936     iKey = sqlite3VdbeIntValue(pIn3);
3937 
3938     /* If the P3 value could not be converted into an integer without
3939     ** loss of information, then special processing is required... */
3940     if( (pIn3->flags & MEM_Int)==0 ){
3941       if( (pIn3->flags & MEM_Real)==0 ){
3942         /* If the P3 value cannot be converted into any kind of a number,
3943         ** then the seek is not possible, so jump to P2 */
3944         VdbeBranchTaken(1,2); goto jump_to_p2;
3945         break;
3946       }
3947 
3948       /* If the approximation iKey is larger than the actual real search
3949       ** term, substitute >= for > and < for <=. e.g. if the search term
3950       ** is 4.9 and the integer approximation 5:
3951       **
3952       **        (x >  4.9)    ->     (x >= 5)
3953       **        (x <= 4.9)    ->     (x <  5)
3954       */
3955       if( pIn3->u.r<(double)iKey ){
3956         assert( OP_SeekGE==(OP_SeekGT-1) );
3957         assert( OP_SeekLT==(OP_SeekLE-1) );
3958         assert( (OP_SeekLE & 0x0001)==(OP_SeekGT & 0x0001) );
3959         if( (oc & 0x0001)==(OP_SeekGT & 0x0001) ) oc--;
3960       }
3961 
3962       /* If the approximation iKey is smaller than the actual real search
3963       ** term, substitute <= for < and > for >=.  */
3964       else if( pIn3->u.r>(double)iKey ){
3965         assert( OP_SeekLE==(OP_SeekLT+1) );
3966         assert( OP_SeekGT==(OP_SeekGE+1) );
3967         assert( (OP_SeekLT & 0x0001)==(OP_SeekGE & 0x0001) );
3968         if( (oc & 0x0001)==(OP_SeekLT & 0x0001) ) oc++;
3969       }
3970     }
3971     rc = sqlite3BtreeMovetoUnpacked(pC->uc.pCursor, 0, (u64)iKey, 0, &res);
3972     pC->movetoTarget = iKey;  /* Used by OP_Delete */
3973     if( rc!=SQLITE_OK ){
3974       goto abort_due_to_error;
3975     }
3976   }else{
3977     /* For a cursor with the BTREE_SEEK_EQ hint, only the OP_SeekGE and
3978     ** OP_SeekLE opcodes are allowed, and these must be immediately followed
3979     ** by an OP_IdxGT or OP_IdxLT opcode, respectively, with the same key.
3980     */
3981     if( sqlite3BtreeCursorHasHint(pC->uc.pCursor, BTREE_SEEK_EQ) ){
3982       eqOnly = 1;
3983       assert( pOp->opcode==OP_SeekGE || pOp->opcode==OP_SeekLE );
3984       assert( pOp[1].opcode==OP_IdxLT || pOp[1].opcode==OP_IdxGT );
3985       assert( pOp[1].p1==pOp[0].p1 );
3986       assert( pOp[1].p2==pOp[0].p2 );
3987       assert( pOp[1].p3==pOp[0].p3 );
3988       assert( pOp[1].p4.i==pOp[0].p4.i );
3989     }
3990 
3991     nField = pOp->p4.i;
3992     assert( pOp->p4type==P4_INT32 );
3993     assert( nField>0 );
3994     r.pKeyInfo = pC->pKeyInfo;
3995     r.nField = (u16)nField;
3996 
3997     /* The next line of code computes as follows, only faster:
3998     **   if( oc==OP_SeekGT || oc==OP_SeekLE ){
3999     **     r.default_rc = -1;
4000     **   }else{
4001     **     r.default_rc = +1;
4002     **   }
4003     */
4004     r.default_rc = ((1 & (oc - OP_SeekLT)) ? -1 : +1);
4005     assert( oc!=OP_SeekGT || r.default_rc==-1 );
4006     assert( oc!=OP_SeekLE || r.default_rc==-1 );
4007     assert( oc!=OP_SeekGE || r.default_rc==+1 );
4008     assert( oc!=OP_SeekLT || r.default_rc==+1 );
4009 
4010     r.aMem = &aMem[pOp->p3];
4011 #ifdef SQLITE_DEBUG
4012     { int i; for(i=0; i<r.nField; i++) assert( memIsValid(&r.aMem[i]) ); }
4013 #endif
4014     r.eqSeen = 0;
4015     rc = sqlite3BtreeMovetoUnpacked(pC->uc.pCursor, &r, 0, 0, &res);
4016     if( rc!=SQLITE_OK ){
4017       goto abort_due_to_error;
4018     }
4019     if( eqOnly && r.eqSeen==0 ){
4020       assert( res!=0 );
4021       goto seek_not_found;
4022     }
4023   }
4024   pC->deferredMoveto = 0;
4025   pC->cacheStatus = CACHE_STALE;
4026 #ifdef SQLITE_TEST
4027   sqlite3_search_count++;
4028 #endif
4029   if( oc>=OP_SeekGE ){  assert( oc==OP_SeekGE || oc==OP_SeekGT );
4030     if( res<0 || (res==0 && oc==OP_SeekGT) ){
4031       res = 0;
4032       rc = sqlite3BtreeNext(pC->uc.pCursor, 0);
4033       if( rc!=SQLITE_OK ){
4034         if( rc==SQLITE_DONE ){
4035           rc = SQLITE_OK;
4036           res = 1;
4037         }else{
4038           goto abort_due_to_error;
4039         }
4040       }
4041     }else{
4042       res = 0;
4043     }
4044   }else{
4045     assert( oc==OP_SeekLT || oc==OP_SeekLE );
4046     if( res>0 || (res==0 && oc==OP_SeekLT) ){
4047       res = 0;
4048       rc = sqlite3BtreePrevious(pC->uc.pCursor, 0);
4049       if( rc!=SQLITE_OK ){
4050         if( rc==SQLITE_DONE ){
4051           rc = SQLITE_OK;
4052           res = 1;
4053         }else{
4054           goto abort_due_to_error;
4055         }
4056       }
4057     }else{
4058       /* res might be negative because the table is empty.  Check to
4059       ** see if this is the case.
4060       */
4061       res = sqlite3BtreeEof(pC->uc.pCursor);
4062     }
4063   }
4064 seek_not_found:
4065   assert( pOp->p2>0 );
4066   VdbeBranchTaken(res!=0,2);
4067   if( res ){
4068     goto jump_to_p2;
4069   }else if( eqOnly ){
4070     assert( pOp[1].opcode==OP_IdxLT || pOp[1].opcode==OP_IdxGT );
4071     pOp++; /* Skip the OP_IdxLt or OP_IdxGT that follows */
4072   }
4073   break;
4074 }
4075 
4076 /* Opcode: SeekHit P1 P2 * * *
4077 ** Synopsis: seekHit=P2
4078 **
4079 ** Set the seekHit flag on cursor P1 to the value in P2.
4080 ** The seekHit flag is used by the IfNoHope opcode.
4081 **
4082 ** P1 must be a valid b-tree cursor.  P2 must be a boolean value,
4083 ** either 0 or 1.
4084 */
4085 case OP_SeekHit: {
4086   VdbeCursor *pC;
4087   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4088   pC = p->apCsr[pOp->p1];
4089   assert( pC!=0 );
4090   assert( pOp->p2==0 || pOp->p2==1 );
4091   pC->seekHit = pOp->p2 & 1;
4092   break;
4093 }
4094 
4095 /* Opcode: Found P1 P2 P3 P4 *
4096 ** Synopsis: key=r[P3@P4]
4097 **
4098 ** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
4099 ** P4>0 then register P3 is the first of P4 registers that form an unpacked
4100 ** record.
4101 **
4102 ** Cursor P1 is on an index btree.  If the record identified by P3 and P4
4103 ** is a prefix of any entry in P1 then a jump is made to P2 and
4104 ** P1 is left pointing at the matching entry.
4105 **
4106 ** This operation leaves the cursor in a state where it can be
4107 ** advanced in the forward direction.  The Next instruction will work,
4108 ** but not the Prev instruction.
4109 **
4110 ** See also: NotFound, NoConflict, NotExists. SeekGe
4111 */
4112 /* Opcode: NotFound P1 P2 P3 P4 *
4113 ** Synopsis: key=r[P3@P4]
4114 **
4115 ** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
4116 ** P4>0 then register P3 is the first of P4 registers that form an unpacked
4117 ** record.
4118 **
4119 ** Cursor P1 is on an index btree.  If the record identified by P3 and P4
4120 ** is not the prefix of any entry in P1 then a jump is made to P2.  If P1
4121 ** does contain an entry whose prefix matches the P3/P4 record then control
4122 ** falls through to the next instruction and P1 is left pointing at the
4123 ** matching entry.
4124 **
4125 ** This operation leaves the cursor in a state where it cannot be
4126 ** advanced in either direction.  In other words, the Next and Prev
4127 ** opcodes do not work after this operation.
4128 **
4129 ** See also: Found, NotExists, NoConflict, IfNoHope
4130 */
4131 /* Opcode: IfNoHope P1 P2 P3 P4 *
4132 ** Synopsis: key=r[P3@P4]
4133 **
4134 ** Register P3 is the first of P4 registers that form an unpacked
4135 ** record.
4136 **
4137 ** Cursor P1 is on an index btree.  If the seekHit flag is set on P1, then
4138 ** this opcode is a no-op.  But if the seekHit flag of P1 is clear, then
4139 ** check to see if there is any entry in P1 that matches the
4140 ** prefix identified by P3 and P4.  If no entry matches the prefix,
4141 ** jump to P2.  Otherwise fall through.
4142 **
4143 ** This opcode behaves like OP_NotFound if the seekHit
4144 ** flag is clear and it behaves like OP_Noop if the seekHit flag is set.
4145 **
4146 ** This opcode is used in IN clause processing for a multi-column key.
4147 ** If an IN clause is attached to an element of the key other than the
4148 ** left-most element, and if there are no matches on the most recent
4149 ** seek over the whole key, then it might be that one of the key element
4150 ** to the left is prohibiting a match, and hence there is "no hope" of
4151 ** any match regardless of how many IN clause elements are checked.
4152 ** In such a case, we abandon the IN clause search early, using this
4153 ** opcode.  The opcode name comes from the fact that the
4154 ** jump is taken if there is "no hope" of achieving a match.
4155 **
4156 ** See also: NotFound, SeekHit
4157 */
4158 /* Opcode: NoConflict P1 P2 P3 P4 *
4159 ** Synopsis: key=r[P3@P4]
4160 **
4161 ** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
4162 ** P4>0 then register P3 is the first of P4 registers that form an unpacked
4163 ** record.
4164 **
4165 ** Cursor P1 is on an index btree.  If the record identified by P3 and P4
4166 ** contains any NULL value, jump immediately to P2.  If all terms of the
4167 ** record are not-NULL then a check is done to determine if any row in the
4168 ** P1 index btree has a matching key prefix.  If there are no matches, jump
4169 ** immediately to P2.  If there is a match, fall through and leave the P1
4170 ** cursor pointing to the matching row.
4171 **
4172 ** This opcode is similar to OP_NotFound with the exceptions that the
4173 ** branch is always taken if any part of the search key input is NULL.
4174 **
4175 ** This operation leaves the cursor in a state where it cannot be
4176 ** advanced in either direction.  In other words, the Next and Prev
4177 ** opcodes do not work after this operation.
4178 **
4179 ** See also: NotFound, Found, NotExists
4180 */
4181 case OP_IfNoHope: {     /* jump, in3 */
4182   VdbeCursor *pC;
4183   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4184   pC = p->apCsr[pOp->p1];
4185   assert( pC!=0 );
4186   if( pC->seekHit ) break;
4187   /* Fall through into OP_NotFound */
4188 }
4189 case OP_NoConflict:     /* jump, in3 */
4190 case OP_NotFound:       /* jump, in3 */
4191 case OP_Found: {        /* jump, in3 */
4192   int alreadyExists;
4193   int takeJump;
4194   int ii;
4195   VdbeCursor *pC;
4196   int res;
4197   UnpackedRecord *pFree;
4198   UnpackedRecord *pIdxKey;
4199   UnpackedRecord r;
4200 
4201 #ifdef SQLITE_TEST
4202   if( pOp->opcode!=OP_NoConflict ) sqlite3_found_count++;
4203 #endif
4204 
4205   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4206   assert( pOp->p4type==P4_INT32 );
4207   pC = p->apCsr[pOp->p1];
4208   assert( pC!=0 );
4209 #ifdef SQLITE_DEBUG
4210   pC->seekOp = pOp->opcode;
4211 #endif
4212   pIn3 = &aMem[pOp->p3];
4213   assert( pC->eCurType==CURTYPE_BTREE );
4214   assert( pC->uc.pCursor!=0 );
4215   assert( pC->isTable==0 );
4216   if( pOp->p4.i>0 ){
4217     r.pKeyInfo = pC->pKeyInfo;
4218     r.nField = (u16)pOp->p4.i;
4219     r.aMem = pIn3;
4220 #ifdef SQLITE_DEBUG
4221     for(ii=0; ii<r.nField; ii++){
4222       assert( memIsValid(&r.aMem[ii]) );
4223       assert( (r.aMem[ii].flags & MEM_Zero)==0 || r.aMem[ii].n==0 );
4224       if( ii ) REGISTER_TRACE(pOp->p3+ii, &r.aMem[ii]);
4225     }
4226 #endif
4227     pIdxKey = &r;
4228     pFree = 0;
4229   }else{
4230     assert( pIn3->flags & MEM_Blob );
4231     rc = ExpandBlob(pIn3);
4232     assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
4233     if( rc ) goto no_mem;
4234     pFree = pIdxKey = sqlite3VdbeAllocUnpackedRecord(pC->pKeyInfo);
4235     if( pIdxKey==0 ) goto no_mem;
4236     sqlite3VdbeRecordUnpack(pC->pKeyInfo, pIn3->n, pIn3->z, pIdxKey);
4237   }
4238   pIdxKey->default_rc = 0;
4239   takeJump = 0;
4240   if( pOp->opcode==OP_NoConflict ){
4241     /* For the OP_NoConflict opcode, take the jump if any of the
4242     ** input fields are NULL, since any key with a NULL will not
4243     ** conflict */
4244     for(ii=0; ii<pIdxKey->nField; ii++){
4245       if( pIdxKey->aMem[ii].flags & MEM_Null ){
4246         takeJump = 1;
4247         break;
4248       }
4249     }
4250   }
4251   rc = sqlite3BtreeMovetoUnpacked(pC->uc.pCursor, pIdxKey, 0, 0, &res);
4252   if( pFree ) sqlite3DbFreeNN(db, pFree);
4253   if( rc!=SQLITE_OK ){
4254     goto abort_due_to_error;
4255   }
4256   pC->seekResult = res;
4257   alreadyExists = (res==0);
4258   pC->nullRow = 1-alreadyExists;
4259   pC->deferredMoveto = 0;
4260   pC->cacheStatus = CACHE_STALE;
4261   if( pOp->opcode==OP_Found ){
4262     VdbeBranchTaken(alreadyExists!=0,2);
4263     if( alreadyExists ) goto jump_to_p2;
4264   }else{
4265     VdbeBranchTaken(takeJump||alreadyExists==0,2);
4266     if( takeJump || !alreadyExists ) goto jump_to_p2;
4267   }
4268   break;
4269 }
4270 
4271 /* Opcode: SeekRowid P1 P2 P3 * *
4272 ** Synopsis: intkey=r[P3]
4273 **
4274 ** P1 is the index of a cursor open on an SQL table btree (with integer
4275 ** keys).  If register P3 does not contain an integer or if P1 does not
4276 ** contain a record with rowid P3 then jump immediately to P2.
4277 ** Or, if P2 is 0, raise an SQLITE_CORRUPT error. If P1 does contain
4278 ** a record with rowid P3 then
4279 ** leave the cursor pointing at that record and fall through to the next
4280 ** instruction.
4281 **
4282 ** The OP_NotExists opcode performs the same operation, but with OP_NotExists
4283 ** the P3 register must be guaranteed to contain an integer value.  With this
4284 ** opcode, register P3 might not contain an integer.
4285 **
4286 ** The OP_NotFound opcode performs the same operation on index btrees
4287 ** (with arbitrary multi-value keys).
4288 **
4289 ** This opcode leaves the cursor in a state where it cannot be advanced
4290 ** in either direction.  In other words, the Next and Prev opcodes will
4291 ** not work following this opcode.
4292 **
4293 ** See also: Found, NotFound, NoConflict, SeekRowid
4294 */
4295 /* Opcode: NotExists P1 P2 P3 * *
4296 ** Synopsis: intkey=r[P3]
4297 **
4298 ** P1 is the index of a cursor open on an SQL table btree (with integer
4299 ** keys).  P3 is an integer rowid.  If P1 does not contain a record with
4300 ** rowid P3 then jump immediately to P2.  Or, if P2 is 0, raise an
4301 ** SQLITE_CORRUPT error. If P1 does contain a record with rowid P3 then
4302 ** leave the cursor pointing at that record and fall through to the next
4303 ** instruction.
4304 **
4305 ** The OP_SeekRowid opcode performs the same operation but also allows the
4306 ** P3 register to contain a non-integer value, in which case the jump is
4307 ** always taken.  This opcode requires that P3 always contain an integer.
4308 **
4309 ** The OP_NotFound opcode performs the same operation on index btrees
4310 ** (with arbitrary multi-value keys).
4311 **
4312 ** This opcode leaves the cursor in a state where it cannot be advanced
4313 ** in either direction.  In other words, the Next and Prev opcodes will
4314 ** not work following this opcode.
4315 **
4316 ** See also: Found, NotFound, NoConflict, SeekRowid
4317 */
4318 case OP_SeekRowid: {        /* jump, in3 */
4319   VdbeCursor *pC;
4320   BtCursor *pCrsr;
4321   int res;
4322   u64 iKey;
4323 
4324   pIn3 = &aMem[pOp->p3];
4325   if( (pIn3->flags & MEM_Int)==0 ){
4326     /* Make sure pIn3->u.i contains a valid integer representation of
4327     ** the key value, but do not change the datatype of the register, as
4328     ** other parts of the perpared statement might be depending on the
4329     ** current datatype. */
4330     u16 origFlags = pIn3->flags;
4331     int isNotInt;
4332     applyAffinity(pIn3, SQLITE_AFF_NUMERIC, encoding);
4333     isNotInt = (pIn3->flags & MEM_Int)==0;
4334     pIn3->flags = origFlags;
4335     if( isNotInt ) goto jump_to_p2;
4336   }
4337   /* Fall through into OP_NotExists */
4338 case OP_NotExists:          /* jump, in3 */
4339   pIn3 = &aMem[pOp->p3];
4340   assert( (pIn3->flags & MEM_Int)!=0 || pOp->opcode==OP_SeekRowid );
4341   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4342   pC = p->apCsr[pOp->p1];
4343   assert( pC!=0 );
4344 #ifdef SQLITE_DEBUG
4345   pC->seekOp = OP_SeekRowid;
4346 #endif
4347   assert( pC->isTable );
4348   assert( pC->eCurType==CURTYPE_BTREE );
4349   pCrsr = pC->uc.pCursor;
4350   assert( pCrsr!=0 );
4351   res = 0;
4352   iKey = pIn3->u.i;
4353   rc = sqlite3BtreeMovetoUnpacked(pCrsr, 0, iKey, 0, &res);
4354   assert( rc==SQLITE_OK || res==0 );
4355   pC->movetoTarget = iKey;  /* Used by OP_Delete */
4356   pC->nullRow = 0;
4357   pC->cacheStatus = CACHE_STALE;
4358   pC->deferredMoveto = 0;
4359   VdbeBranchTaken(res!=0,2);
4360   pC->seekResult = res;
4361   if( res!=0 ){
4362     assert( rc==SQLITE_OK );
4363     if( pOp->p2==0 ){
4364       rc = SQLITE_CORRUPT_BKPT;
4365     }else{
4366       goto jump_to_p2;
4367     }
4368   }
4369   if( rc ) goto abort_due_to_error;
4370   break;
4371 }
4372 
4373 /* Opcode: Sequence P1 P2 * * *
4374 ** Synopsis: r[P2]=cursor[P1].ctr++
4375 **
4376 ** Find the next available sequence number for cursor P1.
4377 ** Write the sequence number into register P2.
4378 ** The sequence number on the cursor is incremented after this
4379 ** instruction.
4380 */
4381 case OP_Sequence: {           /* out2 */
4382   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4383   assert( p->apCsr[pOp->p1]!=0 );
4384   assert( p->apCsr[pOp->p1]->eCurType!=CURTYPE_VTAB );
4385   pOut = out2Prerelease(p, pOp);
4386   pOut->u.i = p->apCsr[pOp->p1]->seqCount++;
4387   break;
4388 }
4389 
4390 
4391 /* Opcode: NewRowid P1 P2 P3 * *
4392 ** Synopsis: r[P2]=rowid
4393 **
4394 ** Get a new integer record number (a.k.a "rowid") used as the key to a table.
4395 ** The record number is not previously used as a key in the database
4396 ** table that cursor P1 points to.  The new record number is written
4397 ** written to register P2.
4398 **
4399 ** If P3>0 then P3 is a register in the root frame of this VDBE that holds
4400 ** the largest previously generated record number. No new record numbers are
4401 ** allowed to be less than this value. When this value reaches its maximum,
4402 ** an SQLITE_FULL error is generated. The P3 register is updated with the '
4403 ** generated record number. This P3 mechanism is used to help implement the
4404 ** AUTOINCREMENT feature.
4405 */
4406 case OP_NewRowid: {           /* out2 */
4407   i64 v;                 /* The new rowid */
4408   VdbeCursor *pC;        /* Cursor of table to get the new rowid */
4409   int res;               /* Result of an sqlite3BtreeLast() */
4410   int cnt;               /* Counter to limit the number of searches */
4411   Mem *pMem;             /* Register holding largest rowid for AUTOINCREMENT */
4412   VdbeFrame *pFrame;     /* Root frame of VDBE */
4413 
4414   v = 0;
4415   res = 0;
4416   pOut = out2Prerelease(p, pOp);
4417   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4418   pC = p->apCsr[pOp->p1];
4419   assert( pC!=0 );
4420   assert( pC->isTable );
4421   assert( pC->eCurType==CURTYPE_BTREE );
4422   assert( pC->uc.pCursor!=0 );
4423   {
4424     /* The next rowid or record number (different terms for the same
4425     ** thing) is obtained in a two-step algorithm.
4426     **
4427     ** First we attempt to find the largest existing rowid and add one
4428     ** to that.  But if the largest existing rowid is already the maximum
4429     ** positive integer, we have to fall through to the second
4430     ** probabilistic algorithm
4431     **
4432     ** The second algorithm is to select a rowid at random and see if
4433     ** it already exists in the table.  If it does not exist, we have
4434     ** succeeded.  If the random rowid does exist, we select a new one
4435     ** and try again, up to 100 times.
4436     */
4437     assert( pC->isTable );
4438 
4439 #ifdef SQLITE_32BIT_ROWID
4440 #   define MAX_ROWID 0x7fffffff
4441 #else
4442     /* Some compilers complain about constants of the form 0x7fffffffffffffff.
4443     ** Others complain about 0x7ffffffffffffffffLL.  The following macro seems
4444     ** to provide the constant while making all compilers happy.
4445     */
4446 #   define MAX_ROWID  (i64)( (((u64)0x7fffffff)<<32) | (u64)0xffffffff )
4447 #endif
4448 
4449     if( !pC->useRandomRowid ){
4450       rc = sqlite3BtreeLast(pC->uc.pCursor, &res);
4451       if( rc!=SQLITE_OK ){
4452         goto abort_due_to_error;
4453       }
4454       if( res ){
4455         v = 1;   /* IMP: R-61914-48074 */
4456       }else{
4457         assert( sqlite3BtreeCursorIsValid(pC->uc.pCursor) );
4458         v = sqlite3BtreeIntegerKey(pC->uc.pCursor);
4459         if( v>=MAX_ROWID ){
4460           pC->useRandomRowid = 1;
4461         }else{
4462           v++;   /* IMP: R-29538-34987 */
4463         }
4464       }
4465     }
4466 
4467 #ifndef SQLITE_OMIT_AUTOINCREMENT
4468     if( pOp->p3 ){
4469       /* Assert that P3 is a valid memory cell. */
4470       assert( pOp->p3>0 );
4471       if( p->pFrame ){
4472         for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
4473         /* Assert that P3 is a valid memory cell. */
4474         assert( pOp->p3<=pFrame->nMem );
4475         pMem = &pFrame->aMem[pOp->p3];
4476       }else{
4477         /* Assert that P3 is a valid memory cell. */
4478         assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
4479         pMem = &aMem[pOp->p3];
4480         memAboutToChange(p, pMem);
4481       }
4482       assert( memIsValid(pMem) );
4483 
4484       REGISTER_TRACE(pOp->p3, pMem);
4485       sqlite3VdbeMemIntegerify(pMem);
4486       assert( (pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
4487       if( pMem->u.i==MAX_ROWID || pC->useRandomRowid ){
4488         rc = SQLITE_FULL;   /* IMP: R-17817-00630 */
4489         goto abort_due_to_error;
4490       }
4491       if( v<pMem->u.i+1 ){
4492         v = pMem->u.i + 1;
4493       }
4494       pMem->u.i = v;
4495     }
4496 #endif
4497     if( pC->useRandomRowid ){
4498       /* IMPLEMENTATION-OF: R-07677-41881 If the largest ROWID is equal to the
4499       ** largest possible integer (9223372036854775807) then the database
4500       ** engine starts picking positive candidate ROWIDs at random until
4501       ** it finds one that is not previously used. */
4502       assert( pOp->p3==0 );  /* We cannot be in random rowid mode if this is
4503                              ** an AUTOINCREMENT table. */
4504       cnt = 0;
4505       do{
4506         sqlite3_randomness(sizeof(v), &v);
4507         v &= (MAX_ROWID>>1); v++;  /* Ensure that v is greater than zero */
4508       }while(  ((rc = sqlite3BtreeMovetoUnpacked(pC->uc.pCursor, 0, (u64)v,
4509                                                  0, &res))==SQLITE_OK)
4510             && (res==0)
4511             && (++cnt<100));
4512       if( rc ) goto abort_due_to_error;
4513       if( res==0 ){
4514         rc = SQLITE_FULL;   /* IMP: R-38219-53002 */
4515         goto abort_due_to_error;
4516       }
4517       assert( v>0 );  /* EV: R-40812-03570 */
4518     }
4519     pC->deferredMoveto = 0;
4520     pC->cacheStatus = CACHE_STALE;
4521   }
4522   pOut->u.i = v;
4523   break;
4524 }
4525 
4526 /* Opcode: Insert P1 P2 P3 P4 P5
4527 ** Synopsis: intkey=r[P3] data=r[P2]
4528 **
4529 ** Write an entry into the table of cursor P1.  A new entry is
4530 ** created if it doesn't already exist or the data for an existing
4531 ** entry is overwritten.  The data is the value MEM_Blob stored in register
4532 ** number P2. The key is stored in register P3. The key must
4533 ** be a MEM_Int.
4534 **
4535 ** If the OPFLAG_NCHANGE flag of P5 is set, then the row change count is
4536 ** incremented (otherwise not).  If the OPFLAG_LASTROWID flag of P5 is set,
4537 ** then rowid is stored for subsequent return by the
4538 ** sqlite3_last_insert_rowid() function (otherwise it is unmodified).
4539 **
4540 ** If the OPFLAG_USESEEKRESULT flag of P5 is set, the implementation might
4541 ** run faster by avoiding an unnecessary seek on cursor P1.  However,
4542 ** the OPFLAG_USESEEKRESULT flag must only be set if there have been no prior
4543 ** seeks on the cursor or if the most recent seek used a key equal to P3.
4544 **
4545 ** If the OPFLAG_ISUPDATE flag is set, then this opcode is part of an
4546 ** UPDATE operation.  Otherwise (if the flag is clear) then this opcode
4547 ** is part of an INSERT operation.  The difference is only important to
4548 ** the update hook.
4549 **
4550 ** Parameter P4 may point to a Table structure, or may be NULL. If it is
4551 ** not NULL, then the update-hook (sqlite3.xUpdateCallback) is invoked
4552 ** following a successful insert.
4553 **
4554 ** (WARNING/TODO: If P1 is a pseudo-cursor and P2 is dynamically
4555 ** allocated, then ownership of P2 is transferred to the pseudo-cursor
4556 ** and register P2 becomes ephemeral.  If the cursor is changed, the
4557 ** value of register P2 will then change.  Make sure this does not
4558 ** cause any problems.)
4559 **
4560 ** This instruction only works on tables.  The equivalent instruction
4561 ** for indices is OP_IdxInsert.
4562 */
4563 /* Opcode: InsertInt P1 P2 P3 P4 P5
4564 ** Synopsis: intkey=P3 data=r[P2]
4565 **
4566 ** This works exactly like OP_Insert except that the key is the
4567 ** integer value P3, not the value of the integer stored in register P3.
4568 */
4569 case OP_Insert:
4570 case OP_InsertInt: {
4571   Mem *pData;       /* MEM cell holding data for the record to be inserted */
4572   Mem *pKey;        /* MEM cell holding key  for the record */
4573   VdbeCursor *pC;   /* Cursor to table into which insert is written */
4574   int seekResult;   /* Result of prior seek or 0 if no USESEEKRESULT flag */
4575   const char *zDb;  /* database name - used by the update hook */
4576   Table *pTab;      /* Table structure - used by update and pre-update hooks */
4577   BtreePayload x;   /* Payload to be inserted */
4578 
4579   pData = &aMem[pOp->p2];
4580   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4581   assert( memIsValid(pData) );
4582   pC = p->apCsr[pOp->p1];
4583   assert( pC!=0 );
4584   assert( pC->eCurType==CURTYPE_BTREE );
4585   assert( pC->uc.pCursor!=0 );
4586   assert( (pOp->p5 & OPFLAG_ISNOOP) || pC->isTable );
4587   assert( pOp->p4type==P4_TABLE || pOp->p4type>=P4_STATIC );
4588   REGISTER_TRACE(pOp->p2, pData);
4589   sqlite3VdbeIncrWriteCounter(p, pC);
4590 
4591   if( pOp->opcode==OP_Insert ){
4592     pKey = &aMem[pOp->p3];
4593     assert( pKey->flags & MEM_Int );
4594     assert( memIsValid(pKey) );
4595     REGISTER_TRACE(pOp->p3, pKey);
4596     x.nKey = pKey->u.i;
4597   }else{
4598     assert( pOp->opcode==OP_InsertInt );
4599     x.nKey = pOp->p3;
4600   }
4601 
4602   if( pOp->p4type==P4_TABLE && HAS_UPDATE_HOOK(db) ){
4603     assert( pC->iDb>=0 );
4604     zDb = db->aDb[pC->iDb].zDbSName;
4605     pTab = pOp->p4.pTab;
4606     assert( (pOp->p5 & OPFLAG_ISNOOP) || HasRowid(pTab) );
4607   }else{
4608     pTab = 0;
4609     zDb = 0;  /* Not needed.  Silence a compiler warning. */
4610   }
4611 
4612 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
4613   /* Invoke the pre-update hook, if any */
4614   if( pTab ){
4615     if( db->xPreUpdateCallback && !(pOp->p5 & OPFLAG_ISUPDATE) ){
4616       sqlite3VdbePreUpdateHook(p, pC, SQLITE_INSERT, zDb, pTab, x.nKey,pOp->p2);
4617     }
4618     if( db->xUpdateCallback==0 || pTab->aCol==0 ){
4619       /* Prevent post-update hook from running in cases when it should not */
4620       pTab = 0;
4621     }
4622   }
4623   if( pOp->p5 & OPFLAG_ISNOOP ) break;
4624 #endif
4625 
4626   if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
4627   if( pOp->p5 & OPFLAG_LASTROWID ) db->lastRowid = x.nKey;
4628   assert( pData->flags & (MEM_Blob|MEM_Str) );
4629   x.pData = pData->z;
4630   x.nData = pData->n;
4631   seekResult = ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0);
4632   if( pData->flags & MEM_Zero ){
4633     x.nZero = pData->u.nZero;
4634   }else{
4635     x.nZero = 0;
4636   }
4637   x.pKey = 0;
4638   rc = sqlite3BtreeInsert(pC->uc.pCursor, &x,
4639       (pOp->p5 & (OPFLAG_APPEND|OPFLAG_SAVEPOSITION)), seekResult
4640   );
4641   pC->deferredMoveto = 0;
4642   pC->cacheStatus = CACHE_STALE;
4643 
4644   /* Invoke the update-hook if required. */
4645   if( rc ) goto abort_due_to_error;
4646   if( pTab ){
4647     assert( db->xUpdateCallback!=0 );
4648     assert( pTab->aCol!=0 );
4649     db->xUpdateCallback(db->pUpdateArg,
4650            (pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT,
4651            zDb, pTab->zName, x.nKey);
4652   }
4653   break;
4654 }
4655 
4656 /* Opcode: Delete P1 P2 P3 P4 P5
4657 **
4658 ** Delete the record at which the P1 cursor is currently pointing.
4659 **
4660 ** If the OPFLAG_SAVEPOSITION bit of the P5 parameter is set, then
4661 ** the cursor will be left pointing at  either the next or the previous
4662 ** record in the table. If it is left pointing at the next record, then
4663 ** the next Next instruction will be a no-op. As a result, in this case
4664 ** it is ok to delete a record from within a Next loop. If
4665 ** OPFLAG_SAVEPOSITION bit of P5 is clear, then the cursor will be
4666 ** left in an undefined state.
4667 **
4668 ** If the OPFLAG_AUXDELETE bit is set on P5, that indicates that this
4669 ** delete one of several associated with deleting a table row and all its
4670 ** associated index entries.  Exactly one of those deletes is the "primary"
4671 ** delete.  The others are all on OPFLAG_FORDELETE cursors or else are
4672 ** marked with the AUXDELETE flag.
4673 **
4674 ** If the OPFLAG_NCHANGE flag of P2 (NB: P2 not P5) is set, then the row
4675 ** change count is incremented (otherwise not).
4676 **
4677 ** P1 must not be pseudo-table.  It has to be a real table with
4678 ** multiple rows.
4679 **
4680 ** If P4 is not NULL then it points to a Table object. In this case either
4681 ** the update or pre-update hook, or both, may be invoked. The P1 cursor must
4682 ** have been positioned using OP_NotFound prior to invoking this opcode in
4683 ** this case. Specifically, if one is configured, the pre-update hook is
4684 ** invoked if P4 is not NULL. The update-hook is invoked if one is configured,
4685 ** P4 is not NULL, and the OPFLAG_NCHANGE flag is set in P2.
4686 **
4687 ** If the OPFLAG_ISUPDATE flag is set in P2, then P3 contains the address
4688 ** of the memory cell that contains the value that the rowid of the row will
4689 ** be set to by the update.
4690 */
4691 case OP_Delete: {
4692   VdbeCursor *pC;
4693   const char *zDb;
4694   Table *pTab;
4695   int opflags;
4696 
4697   opflags = pOp->p2;
4698   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4699   pC = p->apCsr[pOp->p1];
4700   assert( pC!=0 );
4701   assert( pC->eCurType==CURTYPE_BTREE );
4702   assert( pC->uc.pCursor!=0 );
4703   assert( pC->deferredMoveto==0 );
4704   sqlite3VdbeIncrWriteCounter(p, pC);
4705 
4706 #ifdef SQLITE_DEBUG
4707   if( pOp->p4type==P4_TABLE && HasRowid(pOp->p4.pTab) && pOp->p5==0 ){
4708     /* If p5 is zero, the seek operation that positioned the cursor prior to
4709     ** OP_Delete will have also set the pC->movetoTarget field to the rowid of
4710     ** the row that is being deleted */
4711     i64 iKey = sqlite3BtreeIntegerKey(pC->uc.pCursor);
4712     assert( pC->movetoTarget==iKey );
4713   }
4714 #endif
4715 
4716   /* If the update-hook or pre-update-hook will be invoked, set zDb to
4717   ** the name of the db to pass as to it. Also set local pTab to a copy
4718   ** of p4.pTab. Finally, if p5 is true, indicating that this cursor was
4719   ** last moved with OP_Next or OP_Prev, not Seek or NotFound, set
4720   ** VdbeCursor.movetoTarget to the current rowid.  */
4721   if( pOp->p4type==P4_TABLE && HAS_UPDATE_HOOK(db) ){
4722     assert( pC->iDb>=0 );
4723     assert( pOp->p4.pTab!=0 );
4724     zDb = db->aDb[pC->iDb].zDbSName;
4725     pTab = pOp->p4.pTab;
4726     if( (pOp->p5 & OPFLAG_SAVEPOSITION)!=0 && pC->isTable ){
4727       pC->movetoTarget = sqlite3BtreeIntegerKey(pC->uc.pCursor);
4728     }
4729   }else{
4730     zDb = 0;   /* Not needed.  Silence a compiler warning. */
4731     pTab = 0;  /* Not needed.  Silence a compiler warning. */
4732   }
4733 
4734 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
4735   /* Invoke the pre-update-hook if required. */
4736   if( db->xPreUpdateCallback && pOp->p4.pTab ){
4737     assert( !(opflags & OPFLAG_ISUPDATE)
4738          || HasRowid(pTab)==0
4739          || (aMem[pOp->p3].flags & MEM_Int)
4740     );
4741     sqlite3VdbePreUpdateHook(p, pC,
4742         (opflags & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_DELETE,
4743         zDb, pTab, pC->movetoTarget,
4744         pOp->p3
4745     );
4746   }
4747   if( opflags & OPFLAG_ISNOOP ) break;
4748 #endif
4749 
4750   /* Only flags that can be set are SAVEPOISTION and AUXDELETE */
4751   assert( (pOp->p5 & ~(OPFLAG_SAVEPOSITION|OPFLAG_AUXDELETE))==0 );
4752   assert( OPFLAG_SAVEPOSITION==BTREE_SAVEPOSITION );
4753   assert( OPFLAG_AUXDELETE==BTREE_AUXDELETE );
4754 
4755 #ifdef SQLITE_DEBUG
4756   if( p->pFrame==0 ){
4757     if( pC->isEphemeral==0
4758         && (pOp->p5 & OPFLAG_AUXDELETE)==0
4759         && (pC->wrFlag & OPFLAG_FORDELETE)==0
4760       ){
4761       nExtraDelete++;
4762     }
4763     if( pOp->p2 & OPFLAG_NCHANGE ){
4764       nExtraDelete--;
4765     }
4766   }
4767 #endif
4768 
4769   rc = sqlite3BtreeDelete(pC->uc.pCursor, pOp->p5);
4770   pC->cacheStatus = CACHE_STALE;
4771   pC->seekResult = 0;
4772   if( rc ) goto abort_due_to_error;
4773 
4774   /* Invoke the update-hook if required. */
4775   if( opflags & OPFLAG_NCHANGE ){
4776     p->nChange++;
4777     if( db->xUpdateCallback && HasRowid(pTab) ){
4778       db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, pTab->zName,
4779           pC->movetoTarget);
4780       assert( pC->iDb>=0 );
4781     }
4782   }
4783 
4784   break;
4785 }
4786 /* Opcode: ResetCount * * * * *
4787 **
4788 ** The value of the change counter is copied to the database handle
4789 ** change counter (returned by subsequent calls to sqlite3_changes()).
4790 ** Then the VMs internal change counter resets to 0.
4791 ** This is used by trigger programs.
4792 */
4793 case OP_ResetCount: {
4794   sqlite3VdbeSetChanges(db, p->nChange);
4795   p->nChange = 0;
4796   break;
4797 }
4798 
4799 /* Opcode: SorterCompare P1 P2 P3 P4
4800 ** Synopsis: if key(P1)!=trim(r[P3],P4) goto P2
4801 **
4802 ** P1 is a sorter cursor. This instruction compares a prefix of the
4803 ** record blob in register P3 against a prefix of the entry that
4804 ** the sorter cursor currently points to.  Only the first P4 fields
4805 ** of r[P3] and the sorter record are compared.
4806 **
4807 ** If either P3 or the sorter contains a NULL in one of their significant
4808 ** fields (not counting the P4 fields at the end which are ignored) then
4809 ** the comparison is assumed to be equal.
4810 **
4811 ** Fall through to next instruction if the two records compare equal to
4812 ** each other.  Jump to P2 if they are different.
4813 */
4814 case OP_SorterCompare: {
4815   VdbeCursor *pC;
4816   int res;
4817   int nKeyCol;
4818 
4819   pC = p->apCsr[pOp->p1];
4820   assert( isSorter(pC) );
4821   assert( pOp->p4type==P4_INT32 );
4822   pIn3 = &aMem[pOp->p3];
4823   nKeyCol = pOp->p4.i;
4824   res = 0;
4825   rc = sqlite3VdbeSorterCompare(pC, pIn3, nKeyCol, &res);
4826   VdbeBranchTaken(res!=0,2);
4827   if( rc ) goto abort_due_to_error;
4828   if( res ) goto jump_to_p2;
4829   break;
4830 };
4831 
4832 /* Opcode: SorterData P1 P2 P3 * *
4833 ** Synopsis: r[P2]=data
4834 **
4835 ** Write into register P2 the current sorter data for sorter cursor P1.
4836 ** Then clear the column header cache on cursor P3.
4837 **
4838 ** This opcode is normally use to move a record out of the sorter and into
4839 ** a register that is the source for a pseudo-table cursor created using
4840 ** OpenPseudo.  That pseudo-table cursor is the one that is identified by
4841 ** parameter P3.  Clearing the P3 column cache as part of this opcode saves
4842 ** us from having to issue a separate NullRow instruction to clear that cache.
4843 */
4844 case OP_SorterData: {
4845   VdbeCursor *pC;
4846 
4847   pOut = &aMem[pOp->p2];
4848   pC = p->apCsr[pOp->p1];
4849   assert( isSorter(pC) );
4850   rc = sqlite3VdbeSorterRowkey(pC, pOut);
4851   assert( rc!=SQLITE_OK || (pOut->flags & MEM_Blob) );
4852   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4853   if( rc ) goto abort_due_to_error;
4854   p->apCsr[pOp->p3]->cacheStatus = CACHE_STALE;
4855   break;
4856 }
4857 
4858 /* Opcode: RowData P1 P2 P3 * *
4859 ** Synopsis: r[P2]=data
4860 **
4861 ** Write into register P2 the complete row content for the row at
4862 ** which cursor P1 is currently pointing.
4863 ** There is no interpretation of the data.
4864 ** It is just copied onto the P2 register exactly as
4865 ** it is found in the database file.
4866 **
4867 ** If cursor P1 is an index, then the content is the key of the row.
4868 ** If cursor P2 is a table, then the content extracted is the data.
4869 **
4870 ** If the P1 cursor must be pointing to a valid row (not a NULL row)
4871 ** of a real table, not a pseudo-table.
4872 **
4873 ** If P3!=0 then this opcode is allowed to make an ephemeral pointer
4874 ** into the database page.  That means that the content of the output
4875 ** register will be invalidated as soon as the cursor moves - including
4876 ** moves caused by other cursors that "save" the current cursors
4877 ** position in order that they can write to the same table.  If P3==0
4878 ** then a copy of the data is made into memory.  P3!=0 is faster, but
4879 ** P3==0 is safer.
4880 **
4881 ** If P3!=0 then the content of the P2 register is unsuitable for use
4882 ** in OP_Result and any OP_Result will invalidate the P2 register content.
4883 ** The P2 register content is invalidated by opcodes like OP_Function or
4884 ** by any use of another cursor pointing to the same table.
4885 */
4886 case OP_RowData: {
4887   VdbeCursor *pC;
4888   BtCursor *pCrsr;
4889   u32 n;
4890 
4891   pOut = out2Prerelease(p, pOp);
4892 
4893   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4894   pC = p->apCsr[pOp->p1];
4895   assert( pC!=0 );
4896   assert( pC->eCurType==CURTYPE_BTREE );
4897   assert( isSorter(pC)==0 );
4898   assert( pC->nullRow==0 );
4899   assert( pC->uc.pCursor!=0 );
4900   pCrsr = pC->uc.pCursor;
4901 
4902   /* The OP_RowData opcodes always follow OP_NotExists or
4903   ** OP_SeekRowid or OP_Rewind/Op_Next with no intervening instructions
4904   ** that might invalidate the cursor.
4905   ** If this where not the case, on of the following assert()s
4906   ** would fail.  Should this ever change (because of changes in the code
4907   ** generator) then the fix would be to insert a call to
4908   ** sqlite3VdbeCursorMoveto().
4909   */
4910   assert( pC->deferredMoveto==0 );
4911   assert( sqlite3BtreeCursorIsValid(pCrsr) );
4912 #if 0  /* Not required due to the previous to assert() statements */
4913   rc = sqlite3VdbeCursorMoveto(pC);
4914   if( rc!=SQLITE_OK ) goto abort_due_to_error;
4915 #endif
4916 
4917   n = sqlite3BtreePayloadSize(pCrsr);
4918   if( n>(u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
4919     goto too_big;
4920   }
4921   testcase( n==0 );
4922   rc = sqlite3VdbeMemFromBtree(pCrsr, 0, n, pOut);
4923   if( rc ) goto abort_due_to_error;
4924   if( !pOp->p3 ) Deephemeralize(pOut);
4925   UPDATE_MAX_BLOBSIZE(pOut);
4926   REGISTER_TRACE(pOp->p2, pOut);
4927   break;
4928 }
4929 
4930 /* Opcode: Rowid P1 P2 * * *
4931 ** Synopsis: r[P2]=rowid
4932 **
4933 ** Store in register P2 an integer which is the key of the table entry that
4934 ** P1 is currently point to.
4935 **
4936 ** P1 can be either an ordinary table or a virtual table.  There used to
4937 ** be a separate OP_VRowid opcode for use with virtual tables, but this
4938 ** one opcode now works for both table types.
4939 */
4940 case OP_Rowid: {                 /* out2 */
4941   VdbeCursor *pC;
4942   i64 v;
4943   sqlite3_vtab *pVtab;
4944   const sqlite3_module *pModule;
4945 
4946   pOut = out2Prerelease(p, pOp);
4947   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4948   pC = p->apCsr[pOp->p1];
4949   assert( pC!=0 );
4950   assert( pC->eCurType!=CURTYPE_PSEUDO || pC->nullRow );
4951   if( pC->nullRow ){
4952     pOut->flags = MEM_Null;
4953     break;
4954   }else if( pC->deferredMoveto ){
4955     v = pC->movetoTarget;
4956 #ifndef SQLITE_OMIT_VIRTUALTABLE
4957   }else if( pC->eCurType==CURTYPE_VTAB ){
4958     assert( pC->uc.pVCur!=0 );
4959     pVtab = pC->uc.pVCur->pVtab;
4960     pModule = pVtab->pModule;
4961     assert( pModule->xRowid );
4962     rc = pModule->xRowid(pC->uc.pVCur, &v);
4963     sqlite3VtabImportErrmsg(p, pVtab);
4964     if( rc ) goto abort_due_to_error;
4965 #endif /* SQLITE_OMIT_VIRTUALTABLE */
4966   }else{
4967     assert( pC->eCurType==CURTYPE_BTREE );
4968     assert( pC->uc.pCursor!=0 );
4969     rc = sqlite3VdbeCursorRestore(pC);
4970     if( rc ) goto abort_due_to_error;
4971     if( pC->nullRow ){
4972       pOut->flags = MEM_Null;
4973       break;
4974     }
4975     v = sqlite3BtreeIntegerKey(pC->uc.pCursor);
4976   }
4977   pOut->u.i = v;
4978   break;
4979 }
4980 
4981 /* Opcode: NullRow P1 * * * *
4982 **
4983 ** Move the cursor P1 to a null row.  Any OP_Column operations
4984 ** that occur while the cursor is on the null row will always
4985 ** write a NULL.
4986 */
4987 case OP_NullRow: {
4988   VdbeCursor *pC;
4989 
4990   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
4991   pC = p->apCsr[pOp->p1];
4992   assert( pC!=0 );
4993   pC->nullRow = 1;
4994   pC->cacheStatus = CACHE_STALE;
4995   if( pC->eCurType==CURTYPE_BTREE ){
4996     assert( pC->uc.pCursor!=0 );
4997     sqlite3BtreeClearCursor(pC->uc.pCursor);
4998   }
4999 #ifdef SQLITE_DEBUG
5000   if( pC->seekOp==0 ) pC->seekOp = OP_NullRow;
5001 #endif
5002   break;
5003 }
5004 
5005 /* Opcode: SeekEnd P1 * * * *
5006 **
5007 ** Position cursor P1 at the end of the btree for the purpose of
5008 ** appending a new entry onto the btree.
5009 **
5010 ** It is assumed that the cursor is used only for appending and so
5011 ** if the cursor is valid, then the cursor must already be pointing
5012 ** at the end of the btree and so no changes are made to
5013 ** the cursor.
5014 */
5015 /* Opcode: Last P1 P2 * * *
5016 **
5017 ** The next use of the Rowid or Column or Prev instruction for P1
5018 ** will refer to the last entry in the database table or index.
5019 ** If the table or index is empty and P2>0, then jump immediately to P2.
5020 ** If P2 is 0 or if the table or index is not empty, fall through
5021 ** to the following instruction.
5022 **
5023 ** This opcode leaves the cursor configured to move in reverse order,
5024 ** from the end toward the beginning.  In other words, the cursor is
5025 ** configured to use Prev, not Next.
5026 */
5027 case OP_SeekEnd:
5028 case OP_Last: {        /* jump */
5029   VdbeCursor *pC;
5030   BtCursor *pCrsr;
5031   int res;
5032 
5033   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
5034   pC = p->apCsr[pOp->p1];
5035   assert( pC!=0 );
5036   assert( pC->eCurType==CURTYPE_BTREE );
5037   pCrsr = pC->uc.pCursor;
5038   res = 0;
5039   assert( pCrsr!=0 );
5040 #ifdef SQLITE_DEBUG
5041   pC->seekOp = pOp->opcode;
5042 #endif
5043   if( pOp->opcode==OP_SeekEnd ){
5044     assert( pOp->p2==0 );
5045     pC->seekResult = -1;
5046     if( sqlite3BtreeCursorIsValidNN(pCrsr) ){
5047       break;
5048     }
5049   }
5050   rc = sqlite3BtreeLast(pCrsr, &res);
5051   pC->nullRow = (u8)res;
5052   pC->deferredMoveto = 0;
5053   pC->cacheStatus = CACHE_STALE;
5054   if( rc ) goto abort_due_to_error;
5055   if( pOp->p2>0 ){
5056     VdbeBranchTaken(res!=0,2);
5057     if( res ) goto jump_to_p2;
5058   }
5059   break;
5060 }
5061 
5062 /* Opcode: IfSmaller P1 P2 P3 * *
5063 **
5064 ** Estimate the number of rows in the table P1.  Jump to P2 if that
5065 ** estimate is less than approximately 2**(0.1*P3).
5066 */
5067 case OP_IfSmaller: {        /* jump */
5068   VdbeCursor *pC;
5069   BtCursor *pCrsr;
5070   int res;
5071   i64 sz;
5072 
5073   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
5074   pC = p->apCsr[pOp->p1];
5075   assert( pC!=0 );
5076   pCrsr = pC->uc.pCursor;
5077   assert( pCrsr );
5078   rc = sqlite3BtreeFirst(pCrsr, &res);
5079   if( rc ) goto abort_due_to_error;
5080   if( res==0 ){
5081     sz = sqlite3BtreeRowCountEst(pCrsr);
5082     if( ALWAYS(sz>=0) && sqlite3LogEst((u64)sz)<pOp->p3 ) res = 1;
5083   }
5084   VdbeBranchTaken(res!=0,2);
5085   if( res ) goto jump_to_p2;
5086   break;
5087 }
5088 
5089 
5090 /* Opcode: SorterSort P1 P2 * * *
5091 **
5092 ** After all records have been inserted into the Sorter object
5093 ** identified by P1, invoke this opcode to actually do the sorting.
5094 ** Jump to P2 if there are no records to be sorted.
5095 **
5096 ** This opcode is an alias for OP_Sort and OP_Rewind that is used
5097 ** for Sorter objects.
5098 */
5099 /* Opcode: Sort P1 P2 * * *
5100 **
5101 ** This opcode does exactly the same thing as OP_Rewind except that
5102 ** it increments an undocumented global variable used for testing.
5103 **
5104 ** Sorting is accomplished by writing records into a sorting index,
5105 ** then rewinding that index and playing it back from beginning to
5106 ** end.  We use the OP_Sort opcode instead of OP_Rewind to do the
5107 ** rewinding so that the global variable will be incremented and
5108 ** regression tests can determine whether or not the optimizer is
5109 ** correctly optimizing out sorts.
5110 */
5111 case OP_SorterSort:    /* jump */
5112 case OP_Sort: {        /* jump */
5113 #ifdef SQLITE_TEST
5114   sqlite3_sort_count++;
5115   sqlite3_search_count--;
5116 #endif
5117   p->aCounter[SQLITE_STMTSTATUS_SORT]++;
5118   /* Fall through into OP_Rewind */
5119 }
5120 /* Opcode: Rewind P1 P2 * * P5
5121 **
5122 ** The next use of the Rowid or Column or Next instruction for P1
5123 ** will refer to the first entry in the database table or index.
5124 ** If the table or index is empty, jump immediately to P2.
5125 ** If the table or index is not empty, fall through to the following
5126 ** instruction.
5127 **
5128 ** If P5 is non-zero and the table is not empty, then the "skip-next"
5129 ** flag is set on the cursor so that the next OP_Next instruction
5130 ** executed on it is a no-op.
5131 **
5132 ** This opcode leaves the cursor configured to move in forward order,
5133 ** from the beginning toward the end.  In other words, the cursor is
5134 ** configured to use Next, not Prev.
5135 */
5136 case OP_Rewind: {        /* jump */
5137   VdbeCursor *pC;
5138   BtCursor *pCrsr;
5139   int res;
5140 
5141   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
5142   pC = p->apCsr[pOp->p1];
5143   assert( pC!=0 );
5144   assert( isSorter(pC)==(pOp->opcode==OP_SorterSort) );
5145   res = 1;
5146 #ifdef SQLITE_DEBUG
5147   pC->seekOp = OP_Rewind;
5148 #endif
5149   if( isSorter(pC) ){
5150     rc = sqlite3VdbeSorterRewind(pC, &res);
5151   }else{
5152     assert( pC->eCurType==CURTYPE_BTREE );
5153     pCrsr = pC->uc.pCursor;
5154     assert( pCrsr );
5155     rc = sqlite3BtreeFirst(pCrsr, &res);
5156 #ifndef SQLITE_OMIT_WINDOWFUNC
5157     if( pOp->p5 ) sqlite3BtreeSkipNext(pCrsr);
5158 #endif
5159     pC->deferredMoveto = 0;
5160     pC->cacheStatus = CACHE_STALE;
5161   }
5162   if( rc ) goto abort_due_to_error;
5163   pC->nullRow = (u8)res;
5164   assert( pOp->p2>0 && pOp->p2<p->nOp );
5165   VdbeBranchTaken(res!=0,2);
5166   if( res ) goto jump_to_p2;
5167   break;
5168 }
5169 
5170 /* Opcode: Next P1 P2 P3 P4 P5
5171 **
5172 ** Advance cursor P1 so that it points to the next key/data pair in its
5173 ** table or index.  If there are no more key/value pairs then fall through
5174 ** to the following instruction.  But if the cursor advance was successful,
5175 ** jump immediately to P2.
5176 **
5177 ** The Next opcode is only valid following an SeekGT, SeekGE, or
5178 ** OP_Rewind opcode used to position the cursor.  Next is not allowed
5179 ** to follow SeekLT, SeekLE, or OP_Last.
5180 **
5181 ** The P1 cursor must be for a real table, not a pseudo-table.  P1 must have
5182 ** been opened prior to this opcode or the program will segfault.
5183 **
5184 ** The P3 value is a hint to the btree implementation. If P3==1, that
5185 ** means P1 is an SQL index and that this instruction could have been
5186 ** omitted if that index had been unique.  P3 is usually 0.  P3 is
5187 ** always either 0 or 1.
5188 **
5189 ** P4 is always of type P4_ADVANCE. The function pointer points to
5190 ** sqlite3BtreeNext().
5191 **
5192 ** If P5 is positive and the jump is taken, then event counter
5193 ** number P5-1 in the prepared statement is incremented.
5194 **
5195 ** See also: Prev
5196 */
5197 /* Opcode: Prev P1 P2 P3 P4 P5
5198 **
5199 ** Back up cursor P1 so that it points to the previous key/data pair in its
5200 ** table or index.  If there is no previous key/value pairs then fall through
5201 ** to the following instruction.  But if the cursor backup was successful,
5202 ** jump immediately to P2.
5203 **
5204 **
5205 ** The Prev opcode is only valid following an SeekLT, SeekLE, or
5206 ** OP_Last opcode used to position the cursor.  Prev is not allowed
5207 ** to follow SeekGT, SeekGE, or OP_Rewind.
5208 **
5209 ** The P1 cursor must be for a real table, not a pseudo-table.  If P1 is
5210 ** not open then the behavior is undefined.
5211 **
5212 ** The P3 value is a hint to the btree implementation. If P3==1, that
5213 ** means P1 is an SQL index and that this instruction could have been
5214 ** omitted if that index had been unique.  P3 is usually 0.  P3 is
5215 ** always either 0 or 1.
5216 **
5217 ** P4 is always of type P4_ADVANCE. The function pointer points to
5218 ** sqlite3BtreePrevious().
5219 **
5220 ** If P5 is positive and the jump is taken, then event counter
5221 ** number P5-1 in the prepared statement is incremented.
5222 */
5223 /* Opcode: SorterNext P1 P2 * * P5
5224 **
5225 ** This opcode works just like OP_Next except that P1 must be a
5226 ** sorter object for which the OP_SorterSort opcode has been
5227 ** invoked.  This opcode advances the cursor to the next sorted
5228 ** record, or jumps to P2 if there are no more sorted records.
5229 */
5230 case OP_SorterNext: {  /* jump */
5231   VdbeCursor *pC;
5232 
5233   pC = p->apCsr[pOp->p1];
5234   assert( isSorter(pC) );
5235   rc = sqlite3VdbeSorterNext(db, pC);
5236   goto next_tail;
5237 case OP_Prev:          /* jump */
5238 case OP_Next:          /* jump */
5239   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
5240   assert( pOp->p5<ArraySize(p->aCounter) );
5241   pC = p->apCsr[pOp->p1];
5242   assert( pC!=0 );
5243   assert( pC->deferredMoveto==0 );
5244   assert( pC->eCurType==CURTYPE_BTREE );
5245   assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
5246   assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );
5247 
5248   /* The Next opcode is only used after SeekGT, SeekGE, Rewind, and Found.
5249   ** The Prev opcode is only used after SeekLT, SeekLE, and Last. */
5250   assert( pOp->opcode!=OP_Next
5251        || pC->seekOp==OP_SeekGT || pC->seekOp==OP_SeekGE
5252        || pC->seekOp==OP_Rewind || pC->seekOp==OP_Found
5253        || pC->seekOp==OP_NullRow);
5254   assert( pOp->opcode!=OP_Prev
5255        || pC->seekOp==OP_SeekLT || pC->seekOp==OP_SeekLE
5256        || pC->seekOp==OP_Last
5257        || pC->seekOp==OP_NullRow);
5258 
5259   rc = pOp->p4.xAdvance(pC->uc.pCursor, pOp->p3);
5260 next_tail:
5261   pC->cacheStatus = CACHE_STALE;
5262   VdbeBranchTaken(rc==SQLITE_OK,2);
5263   if( rc==SQLITE_OK ){
5264     pC->nullRow = 0;
5265     p->aCounter[pOp->p5]++;
5266 #ifdef SQLITE_TEST
5267     sqlite3_search_count++;
5268 #endif
5269     goto jump_to_p2_and_check_for_interrupt;
5270   }
5271   if( rc!=SQLITE_DONE ) goto abort_due_to_error;
5272   rc = SQLITE_OK;
5273   pC->nullRow = 1;
5274   goto check_for_interrupt;
5275 }
5276 
5277 /* Opcode: IdxInsert P1 P2 P3 P4 P5
5278 ** Synopsis: key=r[P2]
5279 **
5280 ** Register P2 holds an SQL index key made using the
5281 ** MakeRecord instructions.  This opcode writes that key
5282 ** into the index P1.  Data for the entry is nil.
5283 **
5284 ** If P4 is not zero, then it is the number of values in the unpacked
5285 ** key of reg(P2).  In that case, P3 is the index of the first register
5286 ** for the unpacked key.  The availability of the unpacked key can sometimes
5287 ** be an optimization.
5288 **
5289 ** If P5 has the OPFLAG_APPEND bit set, that is a hint to the b-tree layer
5290 ** that this insert is likely to be an append.
5291 **
5292 ** If P5 has the OPFLAG_NCHANGE bit set, then the change counter is
5293 ** incremented by this instruction.  If the OPFLAG_NCHANGE bit is clear,
5294 ** then the change counter is unchanged.
5295 **
5296 ** If the OPFLAG_USESEEKRESULT flag of P5 is set, the implementation might
5297 ** run faster by avoiding an unnecessary seek on cursor P1.  However,
5298 ** the OPFLAG_USESEEKRESULT flag must only be set if there have been no prior
5299 ** seeks on the cursor or if the most recent seek used a key equivalent
5300 ** to P2.
5301 **
5302 ** This instruction only works for indices.  The equivalent instruction
5303 ** for tables is OP_Insert.
5304 */
5305 /* Opcode: SorterInsert P1 P2 * * *
5306 ** Synopsis: key=r[P2]
5307 **
5308 ** Register P2 holds an SQL index key made using the
5309 ** MakeRecord instructions.  This opcode writes that key
5310 ** into the sorter P1.  Data for the entry is nil.
5311 */
5312 case OP_SorterInsert:       /* in2 */
5313 case OP_IdxInsert: {        /* in2 */
5314   VdbeCursor *pC;
5315   BtreePayload x;
5316 
5317   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
5318   pC = p->apCsr[pOp->p1];
5319   sqlite3VdbeIncrWriteCounter(p, pC);
5320   assert( pC!=0 );
5321   assert( isSorter(pC)==(pOp->opcode==OP_SorterInsert) );
5322   pIn2 = &aMem[pOp->p2];
5323   assert( pIn2->flags & MEM_Blob );
5324   if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
5325   assert( pC->eCurType==CURTYPE_BTREE || pOp->opcode==OP_SorterInsert );
5326   assert( pC->isTable==0 );
5327   rc = ExpandBlob(pIn2);
5328   if( rc ) goto abort_due_to_error;
5329   if( pOp->opcode==OP_SorterInsert ){
5330     rc = sqlite3VdbeSorterWrite(pC, pIn2);
5331   }else{
5332     x.nKey = pIn2->n;
5333     x.pKey = pIn2->z;
5334     x.aMem = aMem + pOp->p3;
5335     x.nMem = (u16)pOp->p4.i;
5336     rc = sqlite3BtreeInsert(pC->uc.pCursor, &x,
5337          (pOp->p5 & (OPFLAG_APPEND|OPFLAG_SAVEPOSITION)),
5338         ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
5339         );
5340     assert( pC->deferredMoveto==0 );
5341     pC->cacheStatus = CACHE_STALE;
5342   }
5343   if( rc) goto abort_due_to_error;
5344   break;
5345 }
5346 
5347 /* Opcode: IdxDelete P1 P2 P3 * *
5348 ** Synopsis: key=r[P2@P3]
5349 **
5350 ** The content of P3 registers starting at register P2 form
5351 ** an unpacked index key. This opcode removes that entry from the
5352 ** index opened by cursor P1.
5353 */
5354 case OP_IdxDelete: {
5355   VdbeCursor *pC;
5356   BtCursor *pCrsr;
5357   int res;
5358   UnpackedRecord r;
5359 
5360   assert( pOp->p3>0 );
5361   assert( pOp->p2>0 && pOp->p2+pOp->p3<=(p->nMem+1 - p->nCursor)+1 );
5362   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
5363   pC = p->apCsr[pOp->p1];
5364   assert( pC!=0 );
5365   assert( pC->eCurType==CURTYPE_BTREE );
5366   sqlite3VdbeIncrWriteCounter(p, pC);
5367   pCrsr = pC->uc.pCursor;
5368   assert( pCrsr!=0 );
5369   assert( pOp->p5==0 );
5370   r.pKeyInfo = pC->pKeyInfo;
5371   r.nField = (u16)pOp->p3;
5372   r.default_rc = 0;
5373   r.aMem = &aMem[pOp->p2];
5374   rc = sqlite3BtreeMovetoUnpacked(pCrsr, &r, 0, 0, &res);
5375   if( rc ) goto abort_due_to_error;
5376   if( res==0 ){
5377     rc = sqlite3BtreeDelete(pCrsr, BTREE_AUXDELETE);
5378     if( rc ) goto abort_due_to_error;
5379   }
5380   assert( pC->deferredMoveto==0 );
5381   pC->cacheStatus = CACHE_STALE;
5382   pC->seekResult = 0;
5383   break;
5384 }
5385 
5386 /* Opcode: DeferredSeek P1 * P3 P4 *
5387 ** Synopsis: Move P3 to P1.rowid if needed
5388 **
5389 ** P1 is an open index cursor and P3 is a cursor on the corresponding
5390 ** table.  This opcode does a deferred seek of the P3 table cursor
5391 ** to the row that corresponds to the current row of P1.
5392 **
5393 ** This is a deferred seek.  Nothing actually happens until
5394 ** the cursor is used to read a record.  That way, if no reads
5395 ** occur, no unnecessary I/O happens.
5396 **
5397 ** P4 may be an array of integers (type P4_INTARRAY) containing
5398 ** one entry for each column in the P3 table.  If array entry a(i)
5399 ** is non-zero, then reading column a(i)-1 from cursor P3 is
5400 ** equivalent to performing the deferred seek and then reading column i
5401 ** from P1.  This information is stored in P3 and used to redirect
5402 ** reads against P3 over to P1, thus possibly avoiding the need to
5403 ** seek and read cursor P3.
5404 */
5405 /* Opcode: IdxRowid P1 P2 * * *
5406 ** Synopsis: r[P2]=rowid
5407 **
5408 ** Write into register P2 an integer which is the last entry in the record at
5409 ** the end of the index key pointed to by cursor P1.  This integer should be
5410 ** the rowid of the table entry to which this index entry points.
5411 **
5412 ** See also: Rowid, MakeRecord.
5413 */
5414 case OP_DeferredSeek:
5415 case OP_IdxRowid: {           /* out2 */
5416   VdbeCursor *pC;             /* The P1 index cursor */
5417   VdbeCursor *pTabCur;        /* The P2 table cursor (OP_DeferredSeek only) */
5418   i64 rowid;                  /* Rowid that P1 current points to */
5419 
5420   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
5421   pC = p->apCsr[pOp->p1];
5422   assert( pC!=0 );
5423   assert( pC->eCurType==CURTYPE_BTREE );
5424   assert( pC->uc.pCursor!=0 );
5425   assert( pC->isTable==0 );
5426   assert( pC->deferredMoveto==0 );
5427   assert( !pC->nullRow || pOp->opcode==OP_IdxRowid );
5428 
5429   /* The IdxRowid and Seek opcodes are combined because of the commonality
5430   ** of sqlite3VdbeCursorRestore() and sqlite3VdbeIdxRowid(). */
5431   rc = sqlite3VdbeCursorRestore(pC);
5432 
5433   /* sqlite3VbeCursorRestore() can only fail if the record has been deleted
5434   ** out from under the cursor.  That will never happens for an IdxRowid
5435   ** or Seek opcode */
5436   if( NEVER(rc!=SQLITE_OK) ) goto abort_due_to_error;
5437 
5438   if( !pC->nullRow ){
5439     rowid = 0;  /* Not needed.  Only used to silence a warning. */
5440     rc = sqlite3VdbeIdxRowid(db, pC->uc.pCursor, &rowid);
5441     if( rc!=SQLITE_OK ){
5442       goto abort_due_to_error;
5443     }
5444     if( pOp->opcode==OP_DeferredSeek ){
5445       assert( pOp->p3>=0 && pOp->p3<p->nCursor );
5446       pTabCur = p->apCsr[pOp->p3];
5447       assert( pTabCur!=0 );
5448       assert( pTabCur->eCurType==CURTYPE_BTREE );
5449       assert( pTabCur->uc.pCursor!=0 );
5450       assert( pTabCur->isTable );
5451       pTabCur->nullRow = 0;
5452       pTabCur->movetoTarget = rowid;
5453       pTabCur->deferredMoveto = 1;
5454       assert( pOp->p4type==P4_INTARRAY || pOp->p4.ai==0 );
5455       pTabCur->aAltMap = pOp->p4.ai;
5456       pTabCur->pAltCursor = pC;
5457     }else{
5458       pOut = out2Prerelease(p, pOp);
5459       pOut->u.i = rowid;
5460     }
5461   }else{
5462     assert( pOp->opcode==OP_IdxRowid );
5463     sqlite3VdbeMemSetNull(&aMem[pOp->p2]);
5464   }
5465   break;
5466 }
5467 
5468 /* Opcode: IdxGE P1 P2 P3 P4 P5
5469 ** Synopsis: key=r[P3@P4]
5470 **
5471 ** The P4 register values beginning with P3 form an unpacked index
5472 ** key that omits the PRIMARY KEY.  Compare this key value against the index
5473 ** that P1 is currently pointing to, ignoring the PRIMARY KEY or ROWID
5474 ** fields at the end.
5475 **
5476 ** If the P1 index entry is greater than or equal to the key value
5477 ** then jump to P2.  Otherwise fall through to the next instruction.
5478 */
5479 /* Opcode: IdxGT P1 P2 P3 P4 P5
5480 ** Synopsis: key=r[P3@P4]
5481 **
5482 ** The P4 register values beginning with P3 form an unpacked index
5483 ** key that omits the PRIMARY KEY.  Compare this key value against the index
5484 ** that P1 is currently pointing to, ignoring the PRIMARY KEY or ROWID
5485 ** fields at the end.
5486 **
5487 ** If the P1 index entry is greater than the key value
5488 ** then jump to P2.  Otherwise fall through to the next instruction.
5489 */
5490 /* Opcode: IdxLT P1 P2 P3 P4 P5
5491 ** Synopsis: key=r[P3@P4]
5492 **
5493 ** The P4 register values beginning with P3 form an unpacked index
5494 ** key that omits the PRIMARY KEY or ROWID.  Compare this key value against
5495 ** the index that P1 is currently pointing to, ignoring the PRIMARY KEY or
5496 ** ROWID on the P1 index.
5497 **
5498 ** If the P1 index entry is less than the key value then jump to P2.
5499 ** Otherwise fall through to the next instruction.
5500 */
5501 /* Opcode: IdxLE P1 P2 P3 P4 P5
5502 ** Synopsis: key=r[P3@P4]
5503 **
5504 ** The P4 register values beginning with P3 form an unpacked index
5505 ** key that omits the PRIMARY KEY or ROWID.  Compare this key value against
5506 ** the index that P1 is currently pointing to, ignoring the PRIMARY KEY or
5507 ** ROWID on the P1 index.
5508 **
5509 ** If the P1 index entry is less than or equal to the key value then jump
5510 ** to P2. Otherwise fall through to the next instruction.
5511 */
5512 case OP_IdxLE:          /* jump */
5513 case OP_IdxGT:          /* jump */
5514 case OP_IdxLT:          /* jump */
5515 case OP_IdxGE:  {       /* jump */
5516   VdbeCursor *pC;
5517   int res;
5518   UnpackedRecord r;
5519 
5520   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
5521   pC = p->apCsr[pOp->p1];
5522   assert( pC!=0 );
5523   assert( pC->isOrdered );
5524   assert( pC->eCurType==CURTYPE_BTREE );
5525   assert( pC->uc.pCursor!=0);
5526   assert( pC->deferredMoveto==0 );
5527   assert( pOp->p5==0 || pOp->p5==1 );
5528   assert( pOp->p4type==P4_INT32 );
5529   r.pKeyInfo = pC->pKeyInfo;
5530   r.nField = (u16)pOp->p4.i;
5531   if( pOp->opcode<OP_IdxLT ){
5532     assert( pOp->opcode==OP_IdxLE || pOp->opcode==OP_IdxGT );
5533     r.default_rc = -1;
5534   }else{
5535     assert( pOp->opcode==OP_IdxGE || pOp->opcode==OP_IdxLT );
5536     r.default_rc = 0;
5537   }
5538   r.aMem = &aMem[pOp->p3];
5539 #ifdef SQLITE_DEBUG
5540   {
5541     int i;
5542     for(i=0; i<r.nField; i++){
5543       assert( memIsValid(&r.aMem[i]) );
5544       REGISTER_TRACE(pOp->p3+i, &aMem[pOp->p3+i]);
5545     }
5546   }
5547 #endif
5548   res = 0;  /* Not needed.  Only used to silence a warning. */
5549   rc = sqlite3VdbeIdxKeyCompare(db, pC, &r, &res);
5550   assert( (OP_IdxLE&1)==(OP_IdxLT&1) && (OP_IdxGE&1)==(OP_IdxGT&1) );
5551   if( (pOp->opcode&1)==(OP_IdxLT&1) ){
5552     assert( pOp->opcode==OP_IdxLE || pOp->opcode==OP_IdxLT );
5553     res = -res;
5554   }else{
5555     assert( pOp->opcode==OP_IdxGE || pOp->opcode==OP_IdxGT );
5556     res++;
5557   }
5558   VdbeBranchTaken(res>0,2);
5559   if( rc ) goto abort_due_to_error;
5560   if( res>0 ) goto jump_to_p2;
5561   break;
5562 }
5563 
5564 /* Opcode: Destroy P1 P2 P3 * *
5565 **
5566 ** Delete an entire database table or index whose root page in the database
5567 ** file is given by P1.
5568 **
5569 ** The table being destroyed is in the main database file if P3==0.  If
5570 ** P3==1 then the table to be clear is in the auxiliary database file
5571 ** that is used to store tables create using CREATE TEMPORARY TABLE.
5572 **
5573 ** If AUTOVACUUM is enabled then it is possible that another root page
5574 ** might be moved into the newly deleted root page in order to keep all
5575 ** root pages contiguous at the beginning of the database.  The former
5576 ** value of the root page that moved - its value before the move occurred -
5577 ** is stored in register P2. If no page movement was required (because the
5578 ** table being dropped was already the last one in the database) then a
5579 ** zero is stored in register P2.  If AUTOVACUUM is disabled then a zero
5580 ** is stored in register P2.
5581 **
5582 ** This opcode throws an error if there are any active reader VMs when
5583 ** it is invoked. This is done to avoid the difficulty associated with
5584 ** updating existing cursors when a root page is moved in an AUTOVACUUM
5585 ** database. This error is thrown even if the database is not an AUTOVACUUM
5586 ** db in order to avoid introducing an incompatibility between autovacuum
5587 ** and non-autovacuum modes.
5588 **
5589 ** See also: Clear
5590 */
5591 case OP_Destroy: {     /* out2 */
5592   int iMoved;
5593   int iDb;
5594 
5595   sqlite3VdbeIncrWriteCounter(p, 0);
5596   assert( p->readOnly==0 );
5597   assert( pOp->p1>1 );
5598   pOut = out2Prerelease(p, pOp);
5599   pOut->flags = MEM_Null;
5600   if( db->nVdbeRead > db->nVDestroy+1 ){
5601     rc = SQLITE_LOCKED;
5602     p->errorAction = OE_Abort;
5603     goto abort_due_to_error;
5604   }else{
5605     iDb = pOp->p3;
5606     assert( DbMaskTest(p->btreeMask, iDb) );
5607     iMoved = 0;  /* Not needed.  Only to silence a warning. */
5608     rc = sqlite3BtreeDropTable(db->aDb[iDb].pBt, pOp->p1, &iMoved);
5609     pOut->flags = MEM_Int;
5610     pOut->u.i = iMoved;
5611     if( rc ) goto abort_due_to_error;
5612 #ifndef SQLITE_OMIT_AUTOVACUUM
5613     if( iMoved!=0 ){
5614       sqlite3RootPageMoved(db, iDb, iMoved, pOp->p1);
5615       /* All OP_Destroy operations occur on the same btree */
5616       assert( resetSchemaOnFault==0 || resetSchemaOnFault==iDb+1 );
5617       resetSchemaOnFault = iDb+1;
5618     }
5619 #endif
5620   }
5621   break;
5622 }
5623 
5624 /* Opcode: Clear P1 P2 P3
5625 **
5626 ** Delete all contents of the database table or index whose root page
5627 ** in the database file is given by P1.  But, unlike Destroy, do not
5628 ** remove the table or index from the database file.
5629 **
5630 ** The table being clear is in the main database file if P2==0.  If
5631 ** P2==1 then the table to be clear is in the auxiliary database file
5632 ** that is used to store tables create using CREATE TEMPORARY TABLE.
5633 **
5634 ** If the P3 value is non-zero, then the table referred to must be an
5635 ** intkey table (an SQL table, not an index). In this case the row change
5636 ** count is incremented by the number of rows in the table being cleared.
5637 ** If P3 is greater than zero, then the value stored in register P3 is
5638 ** also incremented by the number of rows in the table being cleared.
5639 **
5640 ** See also: Destroy
5641 */
5642 case OP_Clear: {
5643   int nChange;
5644 
5645   sqlite3VdbeIncrWriteCounter(p, 0);
5646   nChange = 0;
5647   assert( p->readOnly==0 );
5648   assert( DbMaskTest(p->btreeMask, pOp->p2) );
5649   rc = sqlite3BtreeClearTable(
5650       db->aDb[pOp->p2].pBt, pOp->p1, (pOp->p3 ? &nChange : 0)
5651   );
5652   if( pOp->p3 ){
5653     p->nChange += nChange;
5654     if( pOp->p3>0 ){
5655       assert( memIsValid(&aMem[pOp->p3]) );
5656       memAboutToChange(p, &aMem[pOp->p3]);
5657       aMem[pOp->p3].u.i += nChange;
5658     }
5659   }
5660   if( rc ) goto abort_due_to_error;
5661   break;
5662 }
5663 
5664 /* Opcode: ResetSorter P1 * * * *
5665 **
5666 ** Delete all contents from the ephemeral table or sorter
5667 ** that is open on cursor P1.
5668 **
5669 ** This opcode only works for cursors used for sorting and
5670 ** opened with OP_OpenEphemeral or OP_SorterOpen.
5671 */
5672 case OP_ResetSorter: {
5673   VdbeCursor *pC;
5674 
5675   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
5676   pC = p->apCsr[pOp->p1];
5677   assert( pC!=0 );
5678   if( isSorter(pC) ){
5679     sqlite3VdbeSorterReset(db, pC->uc.pSorter);
5680   }else{
5681     assert( pC->eCurType==CURTYPE_BTREE );
5682     assert( pC->isEphemeral );
5683     rc = sqlite3BtreeClearTableOfCursor(pC->uc.pCursor);
5684     if( rc ) goto abort_due_to_error;
5685   }
5686   break;
5687 }
5688 
5689 /* Opcode: CreateBtree P1 P2 P3 * *
5690 ** Synopsis: r[P2]=root iDb=P1 flags=P3
5691 **
5692 ** Allocate a new b-tree in the main database file if P1==0 or in the
5693 ** TEMP database file if P1==1 or in an attached database if
5694 ** P1>1.  The P3 argument must be 1 (BTREE_INTKEY) for a rowid table
5695 ** it must be 2 (BTREE_BLOBKEY) for an index or WITHOUT ROWID table.
5696 ** The root page number of the new b-tree is stored in register P2.
5697 */
5698 case OP_CreateBtree: {          /* out2 */
5699   int pgno;
5700   Db *pDb;
5701 
5702   sqlite3VdbeIncrWriteCounter(p, 0);
5703   pOut = out2Prerelease(p, pOp);
5704   pgno = 0;
5705   assert( pOp->p3==BTREE_INTKEY || pOp->p3==BTREE_BLOBKEY );
5706   assert( pOp->p1>=0 && pOp->p1<db->nDb );
5707   assert( DbMaskTest(p->btreeMask, pOp->p1) );
5708   assert( p->readOnly==0 );
5709   pDb = &db->aDb[pOp->p1];
5710   assert( pDb->pBt!=0 );
5711   rc = sqlite3BtreeCreateTable(pDb->pBt, &pgno, pOp->p3);
5712   if( rc ) goto abort_due_to_error;
5713   pOut->u.i = pgno;
5714   break;
5715 }
5716 
5717 /* Opcode: SqlExec * * * P4 *
5718 **
5719 ** Run the SQL statement or statements specified in the P4 string.
5720 */
5721 case OP_SqlExec: {
5722   sqlite3VdbeIncrWriteCounter(p, 0);
5723   db->nSqlExec++;
5724   rc = sqlite3_exec(db, pOp->p4.z, 0, 0, 0);
5725   db->nSqlExec--;
5726   if( rc ) goto abort_due_to_error;
5727   break;
5728 }
5729 
5730 /* Opcode: ParseSchema P1 * * P4 *
5731 **
5732 ** Read and parse all entries from the SQLITE_MASTER table of database P1
5733 ** that match the WHERE clause P4.  If P4 is a NULL pointer, then the
5734 ** entire schema for P1 is reparsed.
5735 **
5736 ** This opcode invokes the parser to create a new virtual machine,
5737 ** then runs the new virtual machine.  It is thus a re-entrant opcode.
5738 */
5739 case OP_ParseSchema: {
5740   int iDb;
5741   const char *zMaster;
5742   char *zSql;
5743   InitData initData;
5744 
5745   /* Any prepared statement that invokes this opcode will hold mutexes
5746   ** on every btree.  This is a prerequisite for invoking
5747   ** sqlite3InitCallback().
5748   */
5749 #ifdef SQLITE_DEBUG
5750   for(iDb=0; iDb<db->nDb; iDb++){
5751     assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
5752   }
5753 #endif
5754 
5755   iDb = pOp->p1;
5756   assert( iDb>=0 && iDb<db->nDb );
5757   assert( DbHasProperty(db, iDb, DB_SchemaLoaded) );
5758 
5759 #ifndef SQLITE_OMIT_ALTERTABLE
5760   if( pOp->p4.z==0 ){
5761     sqlite3SchemaClear(db->aDb[iDb].pSchema);
5762     db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
5763     rc = sqlite3InitOne(db, iDb, &p->zErrMsg, INITFLAG_AlterTable);
5764     db->mDbFlags |= DBFLAG_SchemaChange;
5765     p->expired = 0;
5766   }else
5767 #endif
5768   {
5769     zMaster = MASTER_NAME;
5770     initData.db = db;
5771     initData.iDb = iDb;
5772     initData.pzErrMsg = &p->zErrMsg;
5773     initData.mInitFlags = 0;
5774     zSql = sqlite3MPrintf(db,
5775        "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s ORDER BY rowid",
5776        db->aDb[iDb].zDbSName, zMaster, pOp->p4.z);
5777     if( zSql==0 ){
5778       rc = SQLITE_NOMEM_BKPT;
5779     }else{
5780       assert( db->init.busy==0 );
5781       db->init.busy = 1;
5782       initData.rc = SQLITE_OK;
5783       assert( !db->mallocFailed );
5784       rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
5785       if( rc==SQLITE_OK ) rc = initData.rc;
5786       sqlite3DbFreeNN(db, zSql);
5787       db->init.busy = 0;
5788     }
5789   }
5790   if( rc ){
5791     sqlite3ResetAllSchemasOfConnection(db);
5792     if( rc==SQLITE_NOMEM ){
5793       goto no_mem;
5794     }
5795     goto abort_due_to_error;
5796   }
5797   break;
5798 }
5799 
5800 #if !defined(SQLITE_OMIT_ANALYZE)
5801 /* Opcode: LoadAnalysis P1 * * * *
5802 **
5803 ** Read the sqlite_stat1 table for database P1 and load the content
5804 ** of that table into the internal index hash table.  This will cause
5805 ** the analysis to be used when preparing all subsequent queries.
5806 */
5807 case OP_LoadAnalysis: {
5808   assert( pOp->p1>=0 && pOp->p1<db->nDb );
5809   rc = sqlite3AnalysisLoad(db, pOp->p1);
5810   if( rc ) goto abort_due_to_error;
5811   break;
5812 }
5813 #endif /* !defined(SQLITE_OMIT_ANALYZE) */
5814 
5815 /* Opcode: DropTable P1 * * P4 *
5816 **
5817 ** Remove the internal (in-memory) data structures that describe
5818 ** the table named P4 in database P1.  This is called after a table
5819 ** is dropped from disk (using the Destroy opcode) in order to keep
5820 ** the internal representation of the
5821 ** schema consistent with what is on disk.
5822 */
5823 case OP_DropTable: {
5824   sqlite3VdbeIncrWriteCounter(p, 0);
5825   sqlite3UnlinkAndDeleteTable(db, pOp->p1, pOp->p4.z);
5826   break;
5827 }
5828 
5829 /* Opcode: DropIndex P1 * * P4 *
5830 **
5831 ** Remove the internal (in-memory) data structures that describe
5832 ** the index named P4 in database P1.  This is called after an index
5833 ** is dropped from disk (using the Destroy opcode)
5834 ** in order to keep the internal representation of the
5835 ** schema consistent with what is on disk.
5836 */
5837 case OP_DropIndex: {
5838   sqlite3VdbeIncrWriteCounter(p, 0);
5839   sqlite3UnlinkAndDeleteIndex(db, pOp->p1, pOp->p4.z);
5840   break;
5841 }
5842 
5843 /* Opcode: DropTrigger P1 * * P4 *
5844 **
5845 ** Remove the internal (in-memory) data structures that describe
5846 ** the trigger named P4 in database P1.  This is called after a trigger
5847 ** is dropped from disk (using the Destroy opcode) in order to keep
5848 ** the internal representation of the
5849 ** schema consistent with what is on disk.
5850 */
5851 case OP_DropTrigger: {
5852   sqlite3VdbeIncrWriteCounter(p, 0);
5853   sqlite3UnlinkAndDeleteTrigger(db, pOp->p1, pOp->p4.z);
5854   break;
5855 }
5856 
5857 
5858 #ifndef SQLITE_OMIT_INTEGRITY_CHECK
5859 /* Opcode: IntegrityCk P1 P2 P3 P4 P5
5860 **
5861 ** Do an analysis of the currently open database.  Store in
5862 ** register P1 the text of an error message describing any problems.
5863 ** If no problems are found, store a NULL in register P1.
5864 **
5865 ** The register P3 contains one less than the maximum number of allowed errors.
5866 ** At most reg(P3) errors will be reported.
5867 ** In other words, the analysis stops as soon as reg(P1) errors are
5868 ** seen.  Reg(P1) is updated with the number of errors remaining.
5869 **
5870 ** The root page numbers of all tables in the database are integers
5871 ** stored in P4_INTARRAY argument.
5872 **
5873 ** If P5 is not zero, the check is done on the auxiliary database
5874 ** file, not the main database file.
5875 **
5876 ** This opcode is used to implement the integrity_check pragma.
5877 */
5878 case OP_IntegrityCk: {
5879   int nRoot;      /* Number of tables to check.  (Number of root pages.) */
5880   int *aRoot;     /* Array of rootpage numbers for tables to be checked */
5881   int nErr;       /* Number of errors reported */
5882   char *z;        /* Text of the error report */
5883   Mem *pnErr;     /* Register keeping track of errors remaining */
5884 
5885   assert( p->bIsReader );
5886   nRoot = pOp->p2;
5887   aRoot = pOp->p4.ai;
5888   assert( nRoot>0 );
5889   assert( aRoot[0]==nRoot );
5890   assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
5891   pnErr = &aMem[pOp->p3];
5892   assert( (pnErr->flags & MEM_Int)!=0 );
5893   assert( (pnErr->flags & (MEM_Str|MEM_Blob))==0 );
5894   pIn1 = &aMem[pOp->p1];
5895   assert( pOp->p5<db->nDb );
5896   assert( DbMaskTest(p->btreeMask, pOp->p5) );
5897   z = sqlite3BtreeIntegrityCheck(db->aDb[pOp->p5].pBt, &aRoot[1], nRoot,
5898                                  (int)pnErr->u.i+1, &nErr);
5899   sqlite3VdbeMemSetNull(pIn1);
5900   if( nErr==0 ){
5901     assert( z==0 );
5902   }else if( z==0 ){
5903     goto no_mem;
5904   }else{
5905     pnErr->u.i -= nErr-1;
5906     sqlite3VdbeMemSetStr(pIn1, z, -1, SQLITE_UTF8, sqlite3_free);
5907   }
5908   UPDATE_MAX_BLOBSIZE(pIn1);
5909   sqlite3VdbeChangeEncoding(pIn1, encoding);
5910   break;
5911 }
5912 #endif /* SQLITE_OMIT_INTEGRITY_CHECK */
5913 
5914 /* Opcode: RowSetAdd P1 P2 * * *
5915 ** Synopsis: rowset(P1)=r[P2]
5916 **
5917 ** Insert the integer value held by register P2 into a RowSet object
5918 ** held in register P1.
5919 **
5920 ** An assertion fails if P2 is not an integer.
5921 */
5922 case OP_RowSetAdd: {       /* in1, in2 */
5923   pIn1 = &aMem[pOp->p1];
5924   pIn2 = &aMem[pOp->p2];
5925   assert( (pIn2->flags & MEM_Int)!=0 );
5926   if( (pIn1->flags & MEM_Blob)==0 ){
5927     if( sqlite3VdbeMemSetRowSet(pIn1) ) goto no_mem;
5928   }
5929   assert( sqlite3VdbeMemIsRowSet(pIn1) );
5930   sqlite3RowSetInsert((RowSet*)pIn1->z, pIn2->u.i);
5931   break;
5932 }
5933 
5934 /* Opcode: RowSetRead P1 P2 P3 * *
5935 ** Synopsis: r[P3]=rowset(P1)
5936 **
5937 ** Extract the smallest value from the RowSet object in P1
5938 ** and put that value into register P3.
5939 ** Or, if RowSet object P1 is initially empty, leave P3
5940 ** unchanged and jump to instruction P2.
5941 */
5942 case OP_RowSetRead: {       /* jump, in1, out3 */
5943   i64 val;
5944 
5945   pIn1 = &aMem[pOp->p1];
5946   assert( (pIn1->flags & MEM_Blob)==0 || sqlite3VdbeMemIsRowSet(pIn1) );
5947   if( (pIn1->flags & MEM_Blob)==0
5948    || sqlite3RowSetNext((RowSet*)pIn1->z, &val)==0
5949   ){
5950     /* The boolean index is empty */
5951     sqlite3VdbeMemSetNull(pIn1);
5952     VdbeBranchTaken(1,2);
5953     goto jump_to_p2_and_check_for_interrupt;
5954   }else{
5955     /* A value was pulled from the index */
5956     VdbeBranchTaken(0,2);
5957     sqlite3VdbeMemSetInt64(&aMem[pOp->p3], val);
5958   }
5959   goto check_for_interrupt;
5960 }
5961 
5962 /* Opcode: RowSetTest P1 P2 P3 P4
5963 ** Synopsis: if r[P3] in rowset(P1) goto P2
5964 **
5965 ** Register P3 is assumed to hold a 64-bit integer value. If register P1
5966 ** contains a RowSet object and that RowSet object contains
5967 ** the value held in P3, jump to register P2. Otherwise, insert the
5968 ** integer in P3 into the RowSet and continue on to the
5969 ** next opcode.
5970 **
5971 ** The RowSet object is optimized for the case where sets of integers
5972 ** are inserted in distinct phases, which each set contains no duplicates.
5973 ** Each set is identified by a unique P4 value. The first set
5974 ** must have P4==0, the final set must have P4==-1, and for all other sets
5975 ** must have P4>0.
5976 **
5977 ** This allows optimizations: (a) when P4==0 there is no need to test
5978 ** the RowSet object for P3, as it is guaranteed not to contain it,
5979 ** (b) when P4==-1 there is no need to insert the value, as it will
5980 ** never be tested for, and (c) when a value that is part of set X is
5981 ** inserted, there is no need to search to see if the same value was
5982 ** previously inserted as part of set X (only if it was previously
5983 ** inserted as part of some other set).
5984 */
5985 case OP_RowSetTest: {                     /* jump, in1, in3 */
5986   int iSet;
5987   int exists;
5988 
5989   pIn1 = &aMem[pOp->p1];
5990   pIn3 = &aMem[pOp->p3];
5991   iSet = pOp->p4.i;
5992   assert( pIn3->flags&MEM_Int );
5993 
5994   /* If there is anything other than a rowset object in memory cell P1,
5995   ** delete it now and initialize P1 with an empty rowset
5996   */
5997   if( (pIn1->flags & MEM_Blob)==0 ){
5998     if( sqlite3VdbeMemSetRowSet(pIn1) ) goto no_mem;
5999   }
6000   assert( sqlite3VdbeMemIsRowSet(pIn1) );
6001   assert( pOp->p4type==P4_INT32 );
6002   assert( iSet==-1 || iSet>=0 );
6003   if( iSet ){
6004     exists = sqlite3RowSetTest((RowSet*)pIn1->z, iSet, pIn3->u.i);
6005     VdbeBranchTaken(exists!=0,2);
6006     if( exists ) goto jump_to_p2;
6007   }
6008   if( iSet>=0 ){
6009     sqlite3RowSetInsert((RowSet*)pIn1->z, pIn3->u.i);
6010   }
6011   break;
6012 }
6013 
6014 
6015 #ifndef SQLITE_OMIT_TRIGGER
6016 
6017 /* Opcode: Program P1 P2 P3 P4 P5
6018 **
6019 ** Execute the trigger program passed as P4 (type P4_SUBPROGRAM).
6020 **
6021 ** P1 contains the address of the memory cell that contains the first memory
6022 ** cell in an array of values used as arguments to the sub-program. P2
6023 ** contains the address to jump to if the sub-program throws an IGNORE
6024 ** exception using the RAISE() function. Register P3 contains the address
6025 ** of a memory cell in this (the parent) VM that is used to allocate the
6026 ** memory required by the sub-vdbe at runtime.
6027 **
6028 ** P4 is a pointer to the VM containing the trigger program.
6029 **
6030 ** If P5 is non-zero, then recursive program invocation is enabled.
6031 */
6032 case OP_Program: {        /* jump */
6033   int nMem;               /* Number of memory registers for sub-program */
6034   int nByte;              /* Bytes of runtime space required for sub-program */
6035   Mem *pRt;               /* Register to allocate runtime space */
6036   Mem *pMem;              /* Used to iterate through memory cells */
6037   Mem *pEnd;              /* Last memory cell in new array */
6038   VdbeFrame *pFrame;      /* New vdbe frame to execute in */
6039   SubProgram *pProgram;   /* Sub-program to execute */
6040   void *t;                /* Token identifying trigger */
6041 
6042   pProgram = pOp->p4.pProgram;
6043   pRt = &aMem[pOp->p3];
6044   assert( pProgram->nOp>0 );
6045 
6046   /* If the p5 flag is clear, then recursive invocation of triggers is
6047   ** disabled for backwards compatibility (p5 is set if this sub-program
6048   ** is really a trigger, not a foreign key action, and the flag set
6049   ** and cleared by the "PRAGMA recursive_triggers" command is clear).
6050   **
6051   ** It is recursive invocation of triggers, at the SQL level, that is
6052   ** disabled. In some cases a single trigger may generate more than one
6053   ** SubProgram (if the trigger may be executed with more than one different
6054   ** ON CONFLICT algorithm). SubProgram structures associated with a
6055   ** single trigger all have the same value for the SubProgram.token
6056   ** variable.  */
6057   if( pOp->p5 ){
6058     t = pProgram->token;
6059     for(pFrame=p->pFrame; pFrame && pFrame->token!=t; pFrame=pFrame->pParent);
6060     if( pFrame ) break;
6061   }
6062 
6063   if( p->nFrame>=db->aLimit[SQLITE_LIMIT_TRIGGER_DEPTH] ){
6064     rc = SQLITE_ERROR;
6065     sqlite3VdbeError(p, "too many levels of trigger recursion");
6066     goto abort_due_to_error;
6067   }
6068 
6069   /* Register pRt is used to store the memory required to save the state
6070   ** of the current program, and the memory required at runtime to execute
6071   ** the trigger program. If this trigger has been fired before, then pRt
6072   ** is already allocated. Otherwise, it must be initialized.  */
6073   if( (pRt->flags&MEM_Blob)==0 ){
6074     /* SubProgram.nMem is set to the number of memory cells used by the
6075     ** program stored in SubProgram.aOp. As well as these, one memory
6076     ** cell is required for each cursor used by the program. Set local
6077     ** variable nMem (and later, VdbeFrame.nChildMem) to this value.
6078     */
6079     nMem = pProgram->nMem + pProgram->nCsr;
6080     assert( nMem>0 );
6081     if( pProgram->nCsr==0 ) nMem++;
6082     nByte = ROUND8(sizeof(VdbeFrame))
6083               + nMem * sizeof(Mem)
6084               + pProgram->nCsr * sizeof(VdbeCursor*)
6085               + (pProgram->nOp + 7)/8;
6086     pFrame = sqlite3DbMallocZero(db, nByte);
6087     if( !pFrame ){
6088       goto no_mem;
6089     }
6090     sqlite3VdbeMemRelease(pRt);
6091     pRt->flags = MEM_Blob|MEM_Dyn;
6092     pRt->z = (char*)pFrame;
6093     pRt->n = nByte;
6094     pRt->xDel = sqlite3VdbeFrameMemDel;
6095 
6096     pFrame->v = p;
6097     pFrame->nChildMem = nMem;
6098     pFrame->nChildCsr = pProgram->nCsr;
6099     pFrame->pc = (int)(pOp - aOp);
6100     pFrame->aMem = p->aMem;
6101     pFrame->nMem = p->nMem;
6102     pFrame->apCsr = p->apCsr;
6103     pFrame->nCursor = p->nCursor;
6104     pFrame->aOp = p->aOp;
6105     pFrame->nOp = p->nOp;
6106     pFrame->token = pProgram->token;
6107 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS
6108     pFrame->anExec = p->anExec;
6109 #endif
6110 #ifdef SQLITE_DEBUG
6111     pFrame->iFrameMagic = SQLITE_FRAME_MAGIC;
6112 #endif
6113 
6114     pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
6115     for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
6116       pMem->flags = MEM_Undefined;
6117       pMem->db = db;
6118     }
6119   }else{
6120     pFrame = (VdbeFrame*)pRt->z;
6121     assert( pRt->xDel==sqlite3VdbeFrameMemDel );
6122     assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem
6123         || (pProgram->nCsr==0 && pProgram->nMem+1==pFrame->nChildMem) );
6124     assert( pProgram->nCsr==pFrame->nChildCsr );
6125     assert( (int)(pOp - aOp)==pFrame->pc );
6126   }
6127 
6128   p->nFrame++;
6129   pFrame->pParent = p->pFrame;
6130   pFrame->lastRowid = db->lastRowid;
6131   pFrame->nChange = p->nChange;
6132   pFrame->nDbChange = p->db->nChange;
6133   assert( pFrame->pAuxData==0 );
6134   pFrame->pAuxData = p->pAuxData;
6135   p->pAuxData = 0;
6136   p->nChange = 0;
6137   p->pFrame = pFrame;
6138   p->aMem = aMem = VdbeFrameMem(pFrame);
6139   p->nMem = pFrame->nChildMem;
6140   p->nCursor = (u16)pFrame->nChildCsr;
6141   p->apCsr = (VdbeCursor **)&aMem[p->nMem];
6142   pFrame->aOnce = (u8*)&p->apCsr[pProgram->nCsr];
6143   memset(pFrame->aOnce, 0, (pProgram->nOp + 7)/8);
6144   p->aOp = aOp = pProgram->aOp;
6145   p->nOp = pProgram->nOp;
6146 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS
6147   p->anExec = 0;
6148 #endif
6149   pOp = &aOp[-1];
6150 
6151   break;
6152 }
6153 
6154 /* Opcode: Param P1 P2 * * *
6155 **
6156 ** This opcode is only ever present in sub-programs called via the
6157 ** OP_Program instruction. Copy a value currently stored in a memory
6158 ** cell of the calling (parent) frame to cell P2 in the current frames
6159 ** address space. This is used by trigger programs to access the new.*
6160 ** and old.* values.
6161 **
6162 ** The address of the cell in the parent frame is determined by adding
6163 ** the value of the P1 argument to the value of the P1 argument to the
6164 ** calling OP_Program instruction.
6165 */
6166 case OP_Param: {           /* out2 */
6167   VdbeFrame *pFrame;
6168   Mem *pIn;
6169   pOut = out2Prerelease(p, pOp);
6170   pFrame = p->pFrame;
6171   pIn = &pFrame->aMem[pOp->p1 + pFrame->aOp[pFrame->pc].p1];
6172   sqlite3VdbeMemShallowCopy(pOut, pIn, MEM_Ephem);
6173   break;
6174 }
6175 
6176 #endif /* #ifndef SQLITE_OMIT_TRIGGER */
6177 
6178 #ifndef SQLITE_OMIT_FOREIGN_KEY
6179 /* Opcode: FkCounter P1 P2 * * *
6180 ** Synopsis: fkctr[P1]+=P2
6181 **
6182 ** Increment a "constraint counter" by P2 (P2 may be negative or positive).
6183 ** If P1 is non-zero, the database constraint counter is incremented
6184 ** (deferred foreign key constraints). Otherwise, if P1 is zero, the
6185 ** statement counter is incremented (immediate foreign key constraints).
6186 */
6187 case OP_FkCounter: {
6188   if( db->flags & SQLITE_DeferFKs ){
6189     db->nDeferredImmCons += pOp->p2;
6190   }else if( pOp->p1 ){
6191     db->nDeferredCons += pOp->p2;
6192   }else{
6193     p->nFkConstraint += pOp->p2;
6194   }
6195   break;
6196 }
6197 
6198 /* Opcode: FkIfZero P1 P2 * * *
6199 ** Synopsis: if fkctr[P1]==0 goto P2
6200 **
6201 ** This opcode tests if a foreign key constraint-counter is currently zero.
6202 ** If so, jump to instruction P2. Otherwise, fall through to the next
6203 ** instruction.
6204 **
6205 ** If P1 is non-zero, then the jump is taken if the database constraint-counter
6206 ** is zero (the one that counts deferred constraint violations). If P1 is
6207 ** zero, the jump is taken if the statement constraint-counter is zero
6208 ** (immediate foreign key constraint violations).
6209 */
6210 case OP_FkIfZero: {         /* jump */
6211   if( pOp->p1 ){
6212     VdbeBranchTaken(db->nDeferredCons==0 && db->nDeferredImmCons==0, 2);
6213     if( db->nDeferredCons==0 && db->nDeferredImmCons==0 ) goto jump_to_p2;
6214   }else{
6215     VdbeBranchTaken(p->nFkConstraint==0 && db->nDeferredImmCons==0, 2);
6216     if( p->nFkConstraint==0 && db->nDeferredImmCons==0 ) goto jump_to_p2;
6217   }
6218   break;
6219 }
6220 #endif /* #ifndef SQLITE_OMIT_FOREIGN_KEY */
6221 
6222 #ifndef SQLITE_OMIT_AUTOINCREMENT
6223 /* Opcode: MemMax P1 P2 * * *
6224 ** Synopsis: r[P1]=max(r[P1],r[P2])
6225 **
6226 ** P1 is a register in the root frame of this VM (the root frame is
6227 ** different from the current frame if this instruction is being executed
6228 ** within a sub-program). Set the value of register P1 to the maximum of
6229 ** its current value and the value in register P2.
6230 **
6231 ** This instruction throws an error if the memory cell is not initially
6232 ** an integer.
6233 */
6234 case OP_MemMax: {        /* in2 */
6235   VdbeFrame *pFrame;
6236   if( p->pFrame ){
6237     for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
6238     pIn1 = &pFrame->aMem[pOp->p1];
6239   }else{
6240     pIn1 = &aMem[pOp->p1];
6241   }
6242   assert( memIsValid(pIn1) );
6243   sqlite3VdbeMemIntegerify(pIn1);
6244   pIn2 = &aMem[pOp->p2];
6245   sqlite3VdbeMemIntegerify(pIn2);
6246   if( pIn1->u.i<pIn2->u.i){
6247     pIn1->u.i = pIn2->u.i;
6248   }
6249   break;
6250 }
6251 #endif /* SQLITE_OMIT_AUTOINCREMENT */
6252 
6253 /* Opcode: IfPos P1 P2 P3 * *
6254 ** Synopsis: if r[P1]>0 then r[P1]-=P3, goto P2
6255 **
6256 ** Register P1 must contain an integer.
6257 ** If the value of register P1 is 1 or greater, subtract P3 from the
6258 ** value in P1 and jump to P2.
6259 **
6260 ** If the initial value of register P1 is less than 1, then the
6261 ** value is unchanged and control passes through to the next instruction.
6262 */
6263 case OP_IfPos: {        /* jump, in1 */
6264   pIn1 = &aMem[pOp->p1];
6265   assert( pIn1->flags&MEM_Int );
6266   VdbeBranchTaken( pIn1->u.i>0, 2);
6267   if( pIn1->u.i>0 ){
6268     pIn1->u.i -= pOp->p3;
6269     goto jump_to_p2;
6270   }
6271   break;
6272 }
6273 
6274 /* Opcode: OffsetLimit P1 P2 P3 * *
6275 ** Synopsis: if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1)
6276 **
6277 ** This opcode performs a commonly used computation associated with
6278 ** LIMIT and OFFSET process.  r[P1] holds the limit counter.  r[P3]
6279 ** holds the offset counter.  The opcode computes the combined value
6280 ** of the LIMIT and OFFSET and stores that value in r[P2].  The r[P2]
6281 ** value computed is the total number of rows that will need to be
6282 ** visited in order to complete the query.
6283 **
6284 ** If r[P3] is zero or negative, that means there is no OFFSET
6285 ** and r[P2] is set to be the value of the LIMIT, r[P1].
6286 **
6287 ** if r[P1] is zero or negative, that means there is no LIMIT
6288 ** and r[P2] is set to -1.
6289 **
6290 ** Otherwise, r[P2] is set to the sum of r[P1] and r[P3].
6291 */
6292 case OP_OffsetLimit: {    /* in1, out2, in3 */
6293   i64 x;
6294   pIn1 = &aMem[pOp->p1];
6295   pIn3 = &aMem[pOp->p3];
6296   pOut = out2Prerelease(p, pOp);
6297   assert( pIn1->flags & MEM_Int );
6298   assert( pIn3->flags & MEM_Int );
6299   x = pIn1->u.i;
6300   if( x<=0 || sqlite3AddInt64(&x, pIn3->u.i>0?pIn3->u.i:0) ){
6301     /* If the LIMIT is less than or equal to zero, loop forever.  This
6302     ** is documented.  But also, if the LIMIT+OFFSET exceeds 2^63 then
6303     ** also loop forever.  This is undocumented.  In fact, one could argue
6304     ** that the loop should terminate.  But assuming 1 billion iterations
6305     ** per second (far exceeding the capabilities of any current hardware)
6306     ** it would take nearly 300 years to actually reach the limit.  So
6307     ** looping forever is a reasonable approximation. */
6308     pOut->u.i = -1;
6309   }else{
6310     pOut->u.i = x;
6311   }
6312   break;
6313 }
6314 
6315 /* Opcode: IfNotZero P1 P2 * * *
6316 ** Synopsis: if r[P1]!=0 then r[P1]--, goto P2
6317 **
6318 ** Register P1 must contain an integer.  If the content of register P1 is
6319 ** initially greater than zero, then decrement the value in register P1.
6320 ** If it is non-zero (negative or positive) and then also jump to P2.
6321 ** If register P1 is initially zero, leave it unchanged and fall through.
6322 */
6323 case OP_IfNotZero: {        /* jump, in1 */
6324   pIn1 = &aMem[pOp->p1];
6325   assert( pIn1->flags&MEM_Int );
6326   VdbeBranchTaken(pIn1->u.i<0, 2);
6327   if( pIn1->u.i ){
6328      if( pIn1->u.i>0 ) pIn1->u.i--;
6329      goto jump_to_p2;
6330   }
6331   break;
6332 }
6333 
6334 /* Opcode: DecrJumpZero P1 P2 * * *
6335 ** Synopsis: if (--r[P1])==0 goto P2
6336 **
6337 ** Register P1 must hold an integer.  Decrement the value in P1
6338 ** and jump to P2 if the new value is exactly zero.
6339 */
6340 case OP_DecrJumpZero: {      /* jump, in1 */
6341   pIn1 = &aMem[pOp->p1];
6342   assert( pIn1->flags&MEM_Int );
6343   if( pIn1->u.i>SMALLEST_INT64 ) pIn1->u.i--;
6344   VdbeBranchTaken(pIn1->u.i==0, 2);
6345   if( pIn1->u.i==0 ) goto jump_to_p2;
6346   break;
6347 }
6348 
6349 
6350 /* Opcode: AggStep * P2 P3 P4 P5
6351 ** Synopsis: accum=r[P3] step(r[P2@P5])
6352 **
6353 ** Execute the xStep function for an aggregate.
6354 ** The function has P5 arguments.  P4 is a pointer to the
6355 ** FuncDef structure that specifies the function.  Register P3 is the
6356 ** accumulator.
6357 **
6358 ** The P5 arguments are taken from register P2 and its
6359 ** successors.
6360 */
6361 /* Opcode: AggInverse * P2 P3 P4 P5
6362 ** Synopsis: accum=r[P3] inverse(r[P2@P5])
6363 **
6364 ** Execute the xInverse function for an aggregate.
6365 ** The function has P5 arguments.  P4 is a pointer to the
6366 ** FuncDef structure that specifies the function.  Register P3 is the
6367 ** accumulator.
6368 **
6369 ** The P5 arguments are taken from register P2 and its
6370 ** successors.
6371 */
6372 /* Opcode: AggStep1 P1 P2 P3 P4 P5
6373 ** Synopsis: accum=r[P3] step(r[P2@P5])
6374 **
6375 ** Execute the xStep (if P1==0) or xInverse (if P1!=0) function for an
6376 ** aggregate.  The function has P5 arguments.  P4 is a pointer to the
6377 ** FuncDef structure that specifies the function.  Register P3 is the
6378 ** accumulator.
6379 **
6380 ** The P5 arguments are taken from register P2 and its
6381 ** successors.
6382 **
6383 ** This opcode is initially coded as OP_AggStep0.  On first evaluation,
6384 ** the FuncDef stored in P4 is converted into an sqlite3_context and
6385 ** the opcode is changed.  In this way, the initialization of the
6386 ** sqlite3_context only happens once, instead of on each call to the
6387 ** step function.
6388 */
6389 case OP_AggInverse:
6390 case OP_AggStep: {
6391   int n;
6392   sqlite3_context *pCtx;
6393 
6394   assert( pOp->p4type==P4_FUNCDEF );
6395   n = pOp->p5;
6396   assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
6397   assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem+1 - p->nCursor)+1) );
6398   assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
6399   pCtx = sqlite3DbMallocRawNN(db, n*sizeof(sqlite3_value*) +
6400                (sizeof(pCtx[0]) + sizeof(Mem) - sizeof(sqlite3_value*)));
6401   if( pCtx==0 ) goto no_mem;
6402   pCtx->pMem = 0;
6403   pCtx->pOut = (Mem*)&(pCtx->argv[n]);
6404   sqlite3VdbeMemInit(pCtx->pOut, db, MEM_Null);
6405   pCtx->pFunc = pOp->p4.pFunc;
6406   pCtx->iOp = (int)(pOp - aOp);
6407   pCtx->pVdbe = p;
6408   pCtx->skipFlag = 0;
6409   pCtx->isError = 0;
6410   pCtx->argc = n;
6411   pOp->p4type = P4_FUNCCTX;
6412   pOp->p4.pCtx = pCtx;
6413 
6414   /* OP_AggInverse must have P1==1 and OP_AggStep must have P1==0 */
6415   assert( pOp->p1==(pOp->opcode==OP_AggInverse) );
6416 
6417   pOp->opcode = OP_AggStep1;
6418   /* Fall through into OP_AggStep */
6419 }
6420 case OP_AggStep1: {
6421   int i;
6422   sqlite3_context *pCtx;
6423   Mem *pMem;
6424 
6425   assert( pOp->p4type==P4_FUNCCTX );
6426   pCtx = pOp->p4.pCtx;
6427   pMem = &aMem[pOp->p3];
6428 
6429 #ifdef SQLITE_DEBUG
6430   if( pOp->p1 ){
6431     /* This is an OP_AggInverse call.  Verify that xStep has always
6432     ** been called at least once prior to any xInverse call. */
6433     assert( pMem->uTemp==0x1122e0e3 );
6434   }else{
6435     /* This is an OP_AggStep call.  Mark it as such. */
6436     pMem->uTemp = 0x1122e0e3;
6437   }
6438 #endif
6439 
6440   /* If this function is inside of a trigger, the register array in aMem[]
6441   ** might change from one evaluation to the next.  The next block of code
6442   ** checks to see if the register array has changed, and if so it
6443   ** reinitializes the relavant parts of the sqlite3_context object */
6444   if( pCtx->pMem != pMem ){
6445     pCtx->pMem = pMem;
6446     for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
6447   }
6448 
6449 #ifdef SQLITE_DEBUG
6450   for(i=0; i<pCtx->argc; i++){
6451     assert( memIsValid(pCtx->argv[i]) );
6452     REGISTER_TRACE(pOp->p2+i, pCtx->argv[i]);
6453   }
6454 #endif
6455 
6456   pMem->n++;
6457   assert( pCtx->pOut->flags==MEM_Null );
6458   assert( pCtx->isError==0 );
6459   assert( pCtx->skipFlag==0 );
6460 #ifndef SQLITE_OMIT_WINDOWFUNC
6461   if( pOp->p1 ){
6462     (pCtx->pFunc->xInverse)(pCtx,pCtx->argc,pCtx->argv);
6463   }else
6464 #endif
6465   (pCtx->pFunc->xSFunc)(pCtx,pCtx->argc,pCtx->argv); /* IMP: R-24505-23230 */
6466 
6467   if( pCtx->isError ){
6468     if( pCtx->isError>0 ){
6469       sqlite3VdbeError(p, "%s", sqlite3_value_text(pCtx->pOut));
6470       rc = pCtx->isError;
6471     }
6472     if( pCtx->skipFlag ){
6473       assert( pOp[-1].opcode==OP_CollSeq );
6474       i = pOp[-1].p1;
6475       if( i ) sqlite3VdbeMemSetInt64(&aMem[i], 1);
6476       pCtx->skipFlag = 0;
6477     }
6478     sqlite3VdbeMemRelease(pCtx->pOut);
6479     pCtx->pOut->flags = MEM_Null;
6480     pCtx->isError = 0;
6481     if( rc ) goto abort_due_to_error;
6482   }
6483   assert( pCtx->pOut->flags==MEM_Null );
6484   assert( pCtx->skipFlag==0 );
6485   break;
6486 }
6487 
6488 /* Opcode: AggFinal P1 P2 * P4 *
6489 ** Synopsis: accum=r[P1] N=P2
6490 **
6491 ** P1 is the memory location that is the accumulator for an aggregate
6492 ** or window function.  Execute the finalizer function
6493 ** for an aggregate and store the result in P1.
6494 **
6495 ** P2 is the number of arguments that the step function takes and
6496 ** P4 is a pointer to the FuncDef for this function.  The P2
6497 ** argument is not used by this opcode.  It is only there to disambiguate
6498 ** functions that can take varying numbers of arguments.  The
6499 ** P4 argument is only needed for the case where
6500 ** the step function was not previously called.
6501 */
6502 /* Opcode: AggValue * P2 P3 P4 *
6503 ** Synopsis: r[P3]=value N=P2
6504 **
6505 ** Invoke the xValue() function and store the result in register P3.
6506 **
6507 ** P2 is the number of arguments that the step function takes and
6508 ** P4 is a pointer to the FuncDef for this function.  The P2
6509 ** argument is not used by this opcode.  It is only there to disambiguate
6510 ** functions that can take varying numbers of arguments.  The
6511 ** P4 argument is only needed for the case where
6512 ** the step function was not previously called.
6513 */
6514 case OP_AggValue:
6515 case OP_AggFinal: {
6516   Mem *pMem;
6517   assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
6518   assert( pOp->p3==0 || pOp->opcode==OP_AggValue );
6519   pMem = &aMem[pOp->p1];
6520   assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
6521 #ifndef SQLITE_OMIT_WINDOWFUNC
6522   if( pOp->p3 ){
6523     rc = sqlite3VdbeMemAggValue(pMem, &aMem[pOp->p3], pOp->p4.pFunc);
6524     pMem = &aMem[pOp->p3];
6525   }else
6526 #endif
6527   {
6528     rc = sqlite3VdbeMemFinalize(pMem, pOp->p4.pFunc);
6529   }
6530 
6531   if( rc ){
6532     sqlite3VdbeError(p, "%s", sqlite3_value_text(pMem));
6533     goto abort_due_to_error;
6534   }
6535   sqlite3VdbeChangeEncoding(pMem, encoding);
6536   UPDATE_MAX_BLOBSIZE(pMem);
6537   if( sqlite3VdbeMemTooBig(pMem) ){
6538     goto too_big;
6539   }
6540   break;
6541 }
6542 
6543 #ifndef SQLITE_OMIT_WAL
6544 /* Opcode: Checkpoint P1 P2 P3 * *
6545 **
6546 ** Checkpoint database P1. This is a no-op if P1 is not currently in
6547 ** WAL mode. Parameter P2 is one of SQLITE_CHECKPOINT_PASSIVE, FULL,
6548 ** RESTART, or TRUNCATE.  Write 1 or 0 into mem[P3] if the checkpoint returns
6549 ** SQLITE_BUSY or not, respectively.  Write the number of pages in the
6550 ** WAL after the checkpoint into mem[P3+1] and the number of pages
6551 ** in the WAL that have been checkpointed after the checkpoint
6552 ** completes into mem[P3+2].  However on an error, mem[P3+1] and
6553 ** mem[P3+2] are initialized to -1.
6554 */
6555 case OP_Checkpoint: {
6556   int i;                          /* Loop counter */
6557   int aRes[3];                    /* Results */
6558   Mem *pMem;                      /* Write results here */
6559 
6560   assert( p->readOnly==0 );
6561   aRes[0] = 0;
6562   aRes[1] = aRes[2] = -1;
6563   assert( pOp->p2==SQLITE_CHECKPOINT_PASSIVE
6564        || pOp->p2==SQLITE_CHECKPOINT_FULL
6565        || pOp->p2==SQLITE_CHECKPOINT_RESTART
6566        || pOp->p2==SQLITE_CHECKPOINT_TRUNCATE
6567   );
6568   rc = sqlite3Checkpoint(db, pOp->p1, pOp->p2, &aRes[1], &aRes[2]);
6569   if( rc ){
6570     if( rc!=SQLITE_BUSY ) goto abort_due_to_error;
6571     rc = SQLITE_OK;
6572     aRes[0] = 1;
6573   }
6574   for(i=0, pMem = &aMem[pOp->p3]; i<3; i++, pMem++){
6575     sqlite3VdbeMemSetInt64(pMem, (i64)aRes[i]);
6576   }
6577   break;
6578 };
6579 #endif
6580 
6581 #ifndef SQLITE_OMIT_PRAGMA
6582 /* Opcode: JournalMode P1 P2 P3 * *
6583 **
6584 ** Change the journal mode of database P1 to P3. P3 must be one of the
6585 ** PAGER_JOURNALMODE_XXX values. If changing between the various rollback
6586 ** modes (delete, truncate, persist, off and memory), this is a simple
6587 ** operation. No IO is required.
6588 **
6589 ** If changing into or out of WAL mode the procedure is more complicated.
6590 **
6591 ** Write a string containing the final journal-mode to register P2.
6592 */
6593 case OP_JournalMode: {    /* out2 */
6594   Btree *pBt;                     /* Btree to change journal mode of */
6595   Pager *pPager;                  /* Pager associated with pBt */
6596   int eNew;                       /* New journal mode */
6597   int eOld;                       /* The old journal mode */
6598 #ifndef SQLITE_OMIT_WAL
6599   const char *zFilename;          /* Name of database file for pPager */
6600 #endif
6601 
6602   pOut = out2Prerelease(p, pOp);
6603   eNew = pOp->p3;
6604   assert( eNew==PAGER_JOURNALMODE_DELETE
6605        || eNew==PAGER_JOURNALMODE_TRUNCATE
6606        || eNew==PAGER_JOURNALMODE_PERSIST
6607        || eNew==PAGER_JOURNALMODE_OFF
6608        || eNew==PAGER_JOURNALMODE_MEMORY
6609        || eNew==PAGER_JOURNALMODE_WAL
6610        || eNew==PAGER_JOURNALMODE_QUERY
6611   );
6612   assert( pOp->p1>=0 && pOp->p1<db->nDb );
6613   assert( p->readOnly==0 );
6614 
6615   pBt = db->aDb[pOp->p1].pBt;
6616   pPager = sqlite3BtreePager(pBt);
6617   eOld = sqlite3PagerGetJournalMode(pPager);
6618   if( eNew==PAGER_JOURNALMODE_QUERY ) eNew = eOld;
6619   if( !sqlite3PagerOkToChangeJournalMode(pPager) ) eNew = eOld;
6620 
6621 #ifndef SQLITE_OMIT_WAL
6622   zFilename = sqlite3PagerFilename(pPager, 1);
6623 
6624   /* Do not allow a transition to journal_mode=WAL for a database
6625   ** in temporary storage or if the VFS does not support shared memory
6626   */
6627   if( eNew==PAGER_JOURNALMODE_WAL
6628    && (sqlite3Strlen30(zFilename)==0           /* Temp file */
6629        || !sqlite3PagerWalSupported(pPager))   /* No shared-memory support */
6630   ){
6631     eNew = eOld;
6632   }
6633 
6634   if( (eNew!=eOld)
6635    && (eOld==PAGER_JOURNALMODE_WAL || eNew==PAGER_JOURNALMODE_WAL)
6636   ){
6637     if( !db->autoCommit || db->nVdbeRead>1 ){
6638       rc = SQLITE_ERROR;
6639       sqlite3VdbeError(p,
6640           "cannot change %s wal mode from within a transaction",
6641           (eNew==PAGER_JOURNALMODE_WAL ? "into" : "out of")
6642       );
6643       goto abort_due_to_error;
6644     }else{
6645 
6646       if( eOld==PAGER_JOURNALMODE_WAL ){
6647         /* If leaving WAL mode, close the log file. If successful, the call
6648         ** to PagerCloseWal() checkpoints and deletes the write-ahead-log
6649         ** file. An EXCLUSIVE lock may still be held on the database file
6650         ** after a successful return.
6651         */
6652         rc = sqlite3PagerCloseWal(pPager, db);
6653         if( rc==SQLITE_OK ){
6654           sqlite3PagerSetJournalMode(pPager, eNew);
6655         }
6656       }else if( eOld==PAGER_JOURNALMODE_MEMORY ){
6657         /* Cannot transition directly from MEMORY to WAL.  Use mode OFF
6658         ** as an intermediate */
6659         sqlite3PagerSetJournalMode(pPager, PAGER_JOURNALMODE_OFF);
6660       }
6661 
6662       /* Open a transaction on the database file. Regardless of the journal
6663       ** mode, this transaction always uses a rollback journal.
6664       */
6665       assert( sqlite3BtreeIsInTrans(pBt)==0 );
6666       if( rc==SQLITE_OK ){
6667         rc = sqlite3BtreeSetVersion(pBt, (eNew==PAGER_JOURNALMODE_WAL ? 2 : 1));
6668       }
6669     }
6670   }
6671 #endif /* ifndef SQLITE_OMIT_WAL */
6672 
6673   if( rc ) eNew = eOld;
6674   eNew = sqlite3PagerSetJournalMode(pPager, eNew);
6675 
6676   pOut->flags = MEM_Str|MEM_Static|MEM_Term;
6677   pOut->z = (char *)sqlite3JournalModename(eNew);
6678   pOut->n = sqlite3Strlen30(pOut->z);
6679   pOut->enc = SQLITE_UTF8;
6680   sqlite3VdbeChangeEncoding(pOut, encoding);
6681   if( rc ) goto abort_due_to_error;
6682   break;
6683 };
6684 #endif /* SQLITE_OMIT_PRAGMA */
6685 
6686 #if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
6687 /* Opcode: Vacuum P1 * * * *
6688 **
6689 ** Vacuum the entire database P1.  P1 is 0 for "main", and 2 or more
6690 ** for an attached database.  The "temp" database may not be vacuumed.
6691 */
6692 case OP_Vacuum: {
6693   assert( p->readOnly==0 );
6694   rc = sqlite3RunVacuum(&p->zErrMsg, db, pOp->p1);
6695   if( rc ) goto abort_due_to_error;
6696   break;
6697 }
6698 #endif
6699 
6700 #if !defined(SQLITE_OMIT_AUTOVACUUM)
6701 /* Opcode: IncrVacuum P1 P2 * * *
6702 **
6703 ** Perform a single step of the incremental vacuum procedure on
6704 ** the P1 database. If the vacuum has finished, jump to instruction
6705 ** P2. Otherwise, fall through to the next instruction.
6706 */
6707 case OP_IncrVacuum: {        /* jump */
6708   Btree *pBt;
6709 
6710   assert( pOp->p1>=0 && pOp->p1<db->nDb );
6711   assert( DbMaskTest(p->btreeMask, pOp->p1) );
6712   assert( p->readOnly==0 );
6713   pBt = db->aDb[pOp->p1].pBt;
6714   rc = sqlite3BtreeIncrVacuum(pBt);
6715   VdbeBranchTaken(rc==SQLITE_DONE,2);
6716   if( rc ){
6717     if( rc!=SQLITE_DONE ) goto abort_due_to_error;
6718     rc = SQLITE_OK;
6719     goto jump_to_p2;
6720   }
6721   break;
6722 }
6723 #endif
6724 
6725 /* Opcode: Expire P1 P2 * * *
6726 **
6727 ** Cause precompiled statements to expire.  When an expired statement
6728 ** is executed using sqlite3_step() it will either automatically
6729 ** reprepare itself (if it was originally created using sqlite3_prepare_v2())
6730 ** or it will fail with SQLITE_SCHEMA.
6731 **
6732 ** If P1 is 0, then all SQL statements become expired. If P1 is non-zero,
6733 ** then only the currently executing statement is expired.
6734 **
6735 ** If P2 is 0, then SQL statements are expired immediately.  If P2 is 1,
6736 ** then running SQL statements are allowed to continue to run to completion.
6737 ** The P2==1 case occurs when a CREATE INDEX or similar schema change happens
6738 ** that might help the statement run faster but which does not affect the
6739 ** correctness of operation.
6740 */
6741 case OP_Expire: {
6742   assert( pOp->p2==0 || pOp->p2==1 );
6743   if( !pOp->p1 ){
6744     sqlite3ExpirePreparedStatements(db, pOp->p2);
6745   }else{
6746     p->expired = pOp->p2+1;
6747   }
6748   break;
6749 }
6750 
6751 #ifndef SQLITE_OMIT_SHARED_CACHE
6752 /* Opcode: TableLock P1 P2 P3 P4 *
6753 ** Synopsis: iDb=P1 root=P2 write=P3
6754 **
6755 ** Obtain a lock on a particular table. This instruction is only used when
6756 ** the shared-cache feature is enabled.
6757 **
6758 ** P1 is the index of the database in sqlite3.aDb[] of the database
6759 ** on which the lock is acquired.  A readlock is obtained if P3==0 or
6760 ** a write lock if P3==1.
6761 **
6762 ** P2 contains the root-page of the table to lock.
6763 **
6764 ** P4 contains a pointer to the name of the table being locked. This is only
6765 ** used to generate an error message if the lock cannot be obtained.
6766 */
6767 case OP_TableLock: {
6768   u8 isWriteLock = (u8)pOp->p3;
6769   if( isWriteLock || 0==(db->flags&SQLITE_ReadUncommit) ){
6770     int p1 = pOp->p1;
6771     assert( p1>=0 && p1<db->nDb );
6772     assert( DbMaskTest(p->btreeMask, p1) );
6773     assert( isWriteLock==0 || isWriteLock==1 );
6774     rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
6775     if( rc ){
6776       if( (rc&0xFF)==SQLITE_LOCKED ){
6777         const char *z = pOp->p4.z;
6778         sqlite3VdbeError(p, "database table is locked: %s", z);
6779       }
6780       goto abort_due_to_error;
6781     }
6782   }
6783   break;
6784 }
6785 #endif /* SQLITE_OMIT_SHARED_CACHE */
6786 
6787 #ifndef SQLITE_OMIT_VIRTUALTABLE
6788 /* Opcode: VBegin * * * P4 *
6789 **
6790 ** P4 may be a pointer to an sqlite3_vtab structure. If so, call the
6791 ** xBegin method for that table.
6792 **
6793 ** Also, whether or not P4 is set, check that this is not being called from
6794 ** within a callback to a virtual table xSync() method. If it is, the error
6795 ** code will be set to SQLITE_LOCKED.
6796 */
6797 case OP_VBegin: {
6798   VTable *pVTab;
6799   pVTab = pOp->p4.pVtab;
6800   rc = sqlite3VtabBegin(db, pVTab);
6801   if( pVTab ) sqlite3VtabImportErrmsg(p, pVTab->pVtab);
6802   if( rc ) goto abort_due_to_error;
6803   break;
6804 }
6805 #endif /* SQLITE_OMIT_VIRTUALTABLE */
6806 
6807 #ifndef SQLITE_OMIT_VIRTUALTABLE
6808 /* Opcode: VCreate P1 P2 * * *
6809 **
6810 ** P2 is a register that holds the name of a virtual table in database
6811 ** P1. Call the xCreate method for that table.
6812 */
6813 case OP_VCreate: {
6814   Mem sMem;          /* For storing the record being decoded */
6815   const char *zTab;  /* Name of the virtual table */
6816 
6817   memset(&sMem, 0, sizeof(sMem));
6818   sMem.db = db;
6819   /* Because P2 is always a static string, it is impossible for the
6820   ** sqlite3VdbeMemCopy() to fail */
6821   assert( (aMem[pOp->p2].flags & MEM_Str)!=0 );
6822   assert( (aMem[pOp->p2].flags & MEM_Static)!=0 );
6823   rc = sqlite3VdbeMemCopy(&sMem, &aMem[pOp->p2]);
6824   assert( rc==SQLITE_OK );
6825   zTab = (const char*)sqlite3_value_text(&sMem);
6826   assert( zTab || db->mallocFailed );
6827   if( zTab ){
6828     rc = sqlite3VtabCallCreate(db, pOp->p1, zTab, &p->zErrMsg);
6829   }
6830   sqlite3VdbeMemRelease(&sMem);
6831   if( rc ) goto abort_due_to_error;
6832   break;
6833 }
6834 #endif /* SQLITE_OMIT_VIRTUALTABLE */
6835 
6836 #ifndef SQLITE_OMIT_VIRTUALTABLE
6837 /* Opcode: VDestroy P1 * * P4 *
6838 **
6839 ** P4 is the name of a virtual table in database P1.  Call the xDestroy method
6840 ** of that table.
6841 */
6842 case OP_VDestroy: {
6843   db->nVDestroy++;
6844   rc = sqlite3VtabCallDestroy(db, pOp->p1, pOp->p4.z);
6845   db->nVDestroy--;
6846   if( rc ) goto abort_due_to_error;
6847   break;
6848 }
6849 #endif /* SQLITE_OMIT_VIRTUALTABLE */
6850 
6851 #ifndef SQLITE_OMIT_VIRTUALTABLE
6852 /* Opcode: VOpen P1 * * P4 *
6853 **
6854 ** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
6855 ** P1 is a cursor number.  This opcode opens a cursor to the virtual
6856 ** table and stores that cursor in P1.
6857 */
6858 case OP_VOpen: {
6859   VdbeCursor *pCur;
6860   sqlite3_vtab_cursor *pVCur;
6861   sqlite3_vtab *pVtab;
6862   const sqlite3_module *pModule;
6863 
6864   assert( p->bIsReader );
6865   pCur = 0;
6866   pVCur = 0;
6867   pVtab = pOp->p4.pVtab->pVtab;
6868   if( pVtab==0 || NEVER(pVtab->pModule==0) ){
6869     rc = SQLITE_LOCKED;
6870     goto abort_due_to_error;
6871   }
6872   pModule = pVtab->pModule;
6873   rc = pModule->xOpen(pVtab, &pVCur);
6874   sqlite3VtabImportErrmsg(p, pVtab);
6875   if( rc ) goto abort_due_to_error;
6876 
6877   /* Initialize sqlite3_vtab_cursor base class */
6878   pVCur->pVtab = pVtab;
6879 
6880   /* Initialize vdbe cursor object */
6881   pCur = allocateCursor(p, pOp->p1, 0, -1, CURTYPE_VTAB);
6882   if( pCur ){
6883     pCur->uc.pVCur = pVCur;
6884     pVtab->nRef++;
6885   }else{
6886     assert( db->mallocFailed );
6887     pModule->xClose(pVCur);
6888     goto no_mem;
6889   }
6890   break;
6891 }
6892 #endif /* SQLITE_OMIT_VIRTUALTABLE */
6893 
6894 #ifndef SQLITE_OMIT_VIRTUALTABLE
6895 /* Opcode: VFilter P1 P2 P3 P4 *
6896 ** Synopsis: iplan=r[P3] zplan='P4'
6897 **
6898 ** P1 is a cursor opened using VOpen.  P2 is an address to jump to if
6899 ** the filtered result set is empty.
6900 **
6901 ** P4 is either NULL or a string that was generated by the xBestIndex
6902 ** method of the module.  The interpretation of the P4 string is left
6903 ** to the module implementation.
6904 **
6905 ** This opcode invokes the xFilter method on the virtual table specified
6906 ** by P1.  The integer query plan parameter to xFilter is stored in register
6907 ** P3. Register P3+1 stores the argc parameter to be passed to the
6908 ** xFilter method. Registers P3+2..P3+1+argc are the argc
6909 ** additional parameters which are passed to
6910 ** xFilter as argv. Register P3+2 becomes argv[0] when passed to xFilter.
6911 **
6912 ** A jump is made to P2 if the result set after filtering would be empty.
6913 */
6914 case OP_VFilter: {   /* jump */
6915   int nArg;
6916   int iQuery;
6917   const sqlite3_module *pModule;
6918   Mem *pQuery;
6919   Mem *pArgc;
6920   sqlite3_vtab_cursor *pVCur;
6921   sqlite3_vtab *pVtab;
6922   VdbeCursor *pCur;
6923   int res;
6924   int i;
6925   Mem **apArg;
6926 
6927   pQuery = &aMem[pOp->p3];
6928   pArgc = &pQuery[1];
6929   pCur = p->apCsr[pOp->p1];
6930   assert( memIsValid(pQuery) );
6931   REGISTER_TRACE(pOp->p3, pQuery);
6932   assert( pCur->eCurType==CURTYPE_VTAB );
6933   pVCur = pCur->uc.pVCur;
6934   pVtab = pVCur->pVtab;
6935   pModule = pVtab->pModule;
6936 
6937   /* Grab the index number and argc parameters */
6938   assert( (pQuery->flags&MEM_Int)!=0 && pArgc->flags==MEM_Int );
6939   nArg = (int)pArgc->u.i;
6940   iQuery = (int)pQuery->u.i;
6941 
6942   /* Invoke the xFilter method */
6943   res = 0;
6944   apArg = p->apArg;
6945   for(i = 0; i<nArg; i++){
6946     apArg[i] = &pArgc[i+1];
6947   }
6948   rc = pModule->xFilter(pVCur, iQuery, pOp->p4.z, nArg, apArg);
6949   sqlite3VtabImportErrmsg(p, pVtab);
6950   if( rc ) goto abort_due_to_error;
6951   res = pModule->xEof(pVCur);
6952   pCur->nullRow = 0;
6953   VdbeBranchTaken(res!=0,2);
6954   if( res ) goto jump_to_p2;
6955   break;
6956 }
6957 #endif /* SQLITE_OMIT_VIRTUALTABLE */
6958 
6959 #ifndef SQLITE_OMIT_VIRTUALTABLE
6960 /* Opcode: VColumn P1 P2 P3 * P5
6961 ** Synopsis: r[P3]=vcolumn(P2)
6962 **
6963 ** Store in register P3 the value of the P2-th column of
6964 ** the current row of the virtual-table of cursor P1.
6965 **
6966 ** If the VColumn opcode is being used to fetch the value of
6967 ** an unchanging column during an UPDATE operation, then the P5
6968 ** value is OPFLAG_NOCHNG.  This will cause the sqlite3_vtab_nochange()
6969 ** function to return true inside the xColumn method of the virtual
6970 ** table implementation.  The P5 column might also contain other
6971 ** bits (OPFLAG_LENGTHARG or OPFLAG_TYPEOFARG) but those bits are
6972 ** unused by OP_VColumn.
6973 */
6974 case OP_VColumn: {
6975   sqlite3_vtab *pVtab;
6976   const sqlite3_module *pModule;
6977   Mem *pDest;
6978   sqlite3_context sContext;
6979 
6980   VdbeCursor *pCur = p->apCsr[pOp->p1];
6981   assert( pCur->eCurType==CURTYPE_VTAB );
6982   assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
6983   pDest = &aMem[pOp->p3];
6984   memAboutToChange(p, pDest);
6985   if( pCur->nullRow ){
6986     sqlite3VdbeMemSetNull(pDest);
6987     break;
6988   }
6989   pVtab = pCur->uc.pVCur->pVtab;
6990   pModule = pVtab->pModule;
6991   assert( pModule->xColumn );
6992   memset(&sContext, 0, sizeof(sContext));
6993   sContext.pOut = pDest;
6994   testcase( (pOp->p5 & OPFLAG_NOCHNG)==0 && pOp->p5!=0 );
6995   if( pOp->p5 & OPFLAG_NOCHNG ){
6996     sqlite3VdbeMemSetNull(pDest);
6997     pDest->flags = MEM_Null|MEM_Zero;
6998     pDest->u.nZero = 0;
6999   }else{
7000     MemSetTypeFlag(pDest, MEM_Null);
7001   }
7002   rc = pModule->xColumn(pCur->uc.pVCur, &sContext, pOp->p2);
7003   sqlite3VtabImportErrmsg(p, pVtab);
7004   if( sContext.isError>0 ){
7005     sqlite3VdbeError(p, "%s", sqlite3_value_text(pDest));
7006     rc = sContext.isError;
7007   }
7008   sqlite3VdbeChangeEncoding(pDest, encoding);
7009   REGISTER_TRACE(pOp->p3, pDest);
7010   UPDATE_MAX_BLOBSIZE(pDest);
7011 
7012   if( sqlite3VdbeMemTooBig(pDest) ){
7013     goto too_big;
7014   }
7015   if( rc ) goto abort_due_to_error;
7016   break;
7017 }
7018 #endif /* SQLITE_OMIT_VIRTUALTABLE */
7019 
7020 #ifndef SQLITE_OMIT_VIRTUALTABLE
7021 /* Opcode: VNext P1 P2 * * *
7022 **
7023 ** Advance virtual table P1 to the next row in its result set and
7024 ** jump to instruction P2.  Or, if the virtual table has reached
7025 ** the end of its result set, then fall through to the next instruction.
7026 */
7027 case OP_VNext: {   /* jump */
7028   sqlite3_vtab *pVtab;
7029   const sqlite3_module *pModule;
7030   int res;
7031   VdbeCursor *pCur;
7032 
7033   res = 0;
7034   pCur = p->apCsr[pOp->p1];
7035   assert( pCur->eCurType==CURTYPE_VTAB );
7036   if( pCur->nullRow ){
7037     break;
7038   }
7039   pVtab = pCur->uc.pVCur->pVtab;
7040   pModule = pVtab->pModule;
7041   assert( pModule->xNext );
7042 
7043   /* Invoke the xNext() method of the module. There is no way for the
7044   ** underlying implementation to return an error if one occurs during
7045   ** xNext(). Instead, if an error occurs, true is returned (indicating that
7046   ** data is available) and the error code returned when xColumn or
7047   ** some other method is next invoked on the save virtual table cursor.
7048   */
7049   rc = pModule->xNext(pCur->uc.pVCur);
7050   sqlite3VtabImportErrmsg(p, pVtab);
7051   if( rc ) goto abort_due_to_error;
7052   res = pModule->xEof(pCur->uc.pVCur);
7053   VdbeBranchTaken(!res,2);
7054   if( !res ){
7055     /* If there is data, jump to P2 */
7056     goto jump_to_p2_and_check_for_interrupt;
7057   }
7058   goto check_for_interrupt;
7059 }
7060 #endif /* SQLITE_OMIT_VIRTUALTABLE */
7061 
7062 #ifndef SQLITE_OMIT_VIRTUALTABLE
7063 /* Opcode: VRename P1 * * P4 *
7064 **
7065 ** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
7066 ** This opcode invokes the corresponding xRename method. The value
7067 ** in register P1 is passed as the zName argument to the xRename method.
7068 */
7069 case OP_VRename: {
7070   sqlite3_vtab *pVtab;
7071   Mem *pName;
7072   int isLegacy;
7073 
7074   isLegacy = (db->flags & SQLITE_LegacyAlter);
7075   db->flags |= SQLITE_LegacyAlter;
7076   pVtab = pOp->p4.pVtab->pVtab;
7077   pName = &aMem[pOp->p1];
7078   assert( pVtab->pModule->xRename );
7079   assert( memIsValid(pName) );
7080   assert( p->readOnly==0 );
7081   REGISTER_TRACE(pOp->p1, pName);
7082   assert( pName->flags & MEM_Str );
7083   testcase( pName->enc==SQLITE_UTF8 );
7084   testcase( pName->enc==SQLITE_UTF16BE );
7085   testcase( pName->enc==SQLITE_UTF16LE );
7086   rc = sqlite3VdbeChangeEncoding(pName, SQLITE_UTF8);
7087   if( rc ) goto abort_due_to_error;
7088   rc = pVtab->pModule->xRename(pVtab, pName->z);
7089   if( isLegacy==0 ) db->flags &= ~SQLITE_LegacyAlter;
7090   sqlite3VtabImportErrmsg(p, pVtab);
7091   p->expired = 0;
7092   if( rc ) goto abort_due_to_error;
7093   break;
7094 }
7095 #endif
7096 
7097 #ifndef SQLITE_OMIT_VIRTUALTABLE
7098 /* Opcode: VUpdate P1 P2 P3 P4 P5
7099 ** Synopsis: data=r[P3@P2]
7100 **
7101 ** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
7102 ** This opcode invokes the corresponding xUpdate method. P2 values
7103 ** are contiguous memory cells starting at P3 to pass to the xUpdate
7104 ** invocation. The value in register (P3+P2-1) corresponds to the
7105 ** p2th element of the argv array passed to xUpdate.
7106 **
7107 ** The xUpdate method will do a DELETE or an INSERT or both.
7108 ** The argv[0] element (which corresponds to memory cell P3)
7109 ** is the rowid of a row to delete.  If argv[0] is NULL then no
7110 ** deletion occurs.  The argv[1] element is the rowid of the new
7111 ** row.  This can be NULL to have the virtual table select the new
7112 ** rowid for itself.  The subsequent elements in the array are
7113 ** the values of columns in the new row.
7114 **
7115 ** If P2==1 then no insert is performed.  argv[0] is the rowid of
7116 ** a row to delete.
7117 **
7118 ** P1 is a boolean flag. If it is set to true and the xUpdate call
7119 ** is successful, then the value returned by sqlite3_last_insert_rowid()
7120 ** is set to the value of the rowid for the row just inserted.
7121 **
7122 ** P5 is the error actions (OE_Replace, OE_Fail, OE_Ignore, etc) to
7123 ** apply in the case of a constraint failure on an insert or update.
7124 */
7125 case OP_VUpdate: {
7126   sqlite3_vtab *pVtab;
7127   const sqlite3_module *pModule;
7128   int nArg;
7129   int i;
7130   sqlite_int64 rowid;
7131   Mem **apArg;
7132   Mem *pX;
7133 
7134   assert( pOp->p2==1        || pOp->p5==OE_Fail   || pOp->p5==OE_Rollback
7135        || pOp->p5==OE_Abort || pOp->p5==OE_Ignore || pOp->p5==OE_Replace
7136   );
7137   assert( p->readOnly==0 );
7138   if( db->mallocFailed ) goto no_mem;
7139   sqlite3VdbeIncrWriteCounter(p, 0);
7140   pVtab = pOp->p4.pVtab->pVtab;
7141   if( pVtab==0 || NEVER(pVtab->pModule==0) ){
7142     rc = SQLITE_LOCKED;
7143     goto abort_due_to_error;
7144   }
7145   pModule = pVtab->pModule;
7146   nArg = pOp->p2;
7147   assert( pOp->p4type==P4_VTAB );
7148   if( ALWAYS(pModule->xUpdate) ){
7149     u8 vtabOnConflict = db->vtabOnConflict;
7150     apArg = p->apArg;
7151     pX = &aMem[pOp->p3];
7152     for(i=0; i<nArg; i++){
7153       assert( memIsValid(pX) );
7154       memAboutToChange(p, pX);
7155       apArg[i] = pX;
7156       pX++;
7157     }
7158     db->vtabOnConflict = pOp->p5;
7159     rc = pModule->xUpdate(pVtab, nArg, apArg, &rowid);
7160     db->vtabOnConflict = vtabOnConflict;
7161     sqlite3VtabImportErrmsg(p, pVtab);
7162     if( rc==SQLITE_OK && pOp->p1 ){
7163       assert( nArg>1 && apArg[0] && (apArg[0]->flags&MEM_Null) );
7164       db->lastRowid = rowid;
7165     }
7166     if( (rc&0xff)==SQLITE_CONSTRAINT && pOp->p4.pVtab->bConstraint ){
7167       if( pOp->p5==OE_Ignore ){
7168         rc = SQLITE_OK;
7169       }else{
7170         p->errorAction = ((pOp->p5==OE_Replace) ? OE_Abort : pOp->p5);
7171       }
7172     }else{
7173       p->nChange++;
7174     }
7175     if( rc ) goto abort_due_to_error;
7176   }
7177   break;
7178 }
7179 #endif /* SQLITE_OMIT_VIRTUALTABLE */
7180 
7181 #ifndef  SQLITE_OMIT_PAGER_PRAGMAS
7182 /* Opcode: Pagecount P1 P2 * * *
7183 **
7184 ** Write the current number of pages in database P1 to memory cell P2.
7185 */
7186 case OP_Pagecount: {            /* out2 */
7187   pOut = out2Prerelease(p, pOp);
7188   pOut->u.i = sqlite3BtreeLastPage(db->aDb[pOp->p1].pBt);
7189   break;
7190 }
7191 #endif
7192 
7193 
7194 #ifndef  SQLITE_OMIT_PAGER_PRAGMAS
7195 /* Opcode: MaxPgcnt P1 P2 P3 * *
7196 **
7197 ** Try to set the maximum page count for database P1 to the value in P3.
7198 ** Do not let the maximum page count fall below the current page count and
7199 ** do not change the maximum page count value if P3==0.
7200 **
7201 ** Store the maximum page count after the change in register P2.
7202 */
7203 case OP_MaxPgcnt: {            /* out2 */
7204   unsigned int newMax;
7205   Btree *pBt;
7206 
7207   pOut = out2Prerelease(p, pOp);
7208   pBt = db->aDb[pOp->p1].pBt;
7209   newMax = 0;
7210   if( pOp->p3 ){
7211     newMax = sqlite3BtreeLastPage(pBt);
7212     if( newMax < (unsigned)pOp->p3 ) newMax = (unsigned)pOp->p3;
7213   }
7214   pOut->u.i = sqlite3BtreeMaxPageCount(pBt, newMax);
7215   break;
7216 }
7217 #endif
7218 
7219 /* Opcode: Function0 P1 P2 P3 P4 P5
7220 ** Synopsis: r[P3]=func(r[P2@P5])
7221 **
7222 ** Invoke a user function (P4 is a pointer to a FuncDef object that
7223 ** defines the function) with P5 arguments taken from register P2 and
7224 ** successors.  The result of the function is stored in register P3.
7225 ** Register P3 must not be one of the function inputs.
7226 **
7227 ** P1 is a 32-bit bitmask indicating whether or not each argument to the
7228 ** function was determined to be constant at compile time. If the first
7229 ** argument was constant then bit 0 of P1 is set. This is used to determine
7230 ** whether meta data associated with a user function argument using the
7231 ** sqlite3_set_auxdata() API may be safely retained until the next
7232 ** invocation of this opcode.
7233 **
7234 ** See also: Function, AggStep, AggFinal
7235 */
7236 /* Opcode: Function P1 P2 P3 P4 P5
7237 ** Synopsis: r[P3]=func(r[P2@P5])
7238 **
7239 ** Invoke a user function (P4 is a pointer to an sqlite3_context object that
7240 ** contains a pointer to the function to be run) with P5 arguments taken
7241 ** from register P2 and successors.  The result of the function is stored
7242 ** in register P3.  Register P3 must not be one of the function inputs.
7243 **
7244 ** P1 is a 32-bit bitmask indicating whether or not each argument to the
7245 ** function was determined to be constant at compile time. If the first
7246 ** argument was constant then bit 0 of P1 is set. This is used to determine
7247 ** whether meta data associated with a user function argument using the
7248 ** sqlite3_set_auxdata() API may be safely retained until the next
7249 ** invocation of this opcode.
7250 **
7251 ** SQL functions are initially coded as OP_Function0 with P4 pointing
7252 ** to a FuncDef object.  But on first evaluation, the P4 operand is
7253 ** automatically converted into an sqlite3_context object and the operation
7254 ** changed to this OP_Function opcode.  In this way, the initialization of
7255 ** the sqlite3_context object occurs only once, rather than once for each
7256 ** evaluation of the function.
7257 **
7258 ** See also: Function0, AggStep, AggFinal
7259 */
7260 case OP_PureFunc0:              /* group */
7261 case OP_Function0: {            /* group */
7262   int n;
7263   sqlite3_context *pCtx;
7264 
7265   assert( pOp->p4type==P4_FUNCDEF );
7266   n = pOp->p5;
7267   assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
7268   assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem+1 - p->nCursor)+1) );
7269   assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
7270   pCtx = sqlite3DbMallocRawNN(db, sizeof(*pCtx) + (n-1)*sizeof(sqlite3_value*));
7271   if( pCtx==0 ) goto no_mem;
7272   pCtx->pOut = 0;
7273   pCtx->pFunc = pOp->p4.pFunc;
7274   pCtx->iOp = (int)(pOp - aOp);
7275   pCtx->pVdbe = p;
7276   pCtx->isError = 0;
7277   pCtx->argc = n;
7278   pOp->p4type = P4_FUNCCTX;
7279   pOp->p4.pCtx = pCtx;
7280   assert( OP_PureFunc == OP_PureFunc0+2 );
7281   assert( OP_Function == OP_Function0+2 );
7282   pOp->opcode += 2;
7283   /* Fall through into OP_Function */
7284 }
7285 case OP_PureFunc:              /* group */
7286 case OP_Function: {            /* group */
7287   int i;
7288   sqlite3_context *pCtx;
7289 
7290   assert( pOp->p4type==P4_FUNCCTX );
7291   pCtx = pOp->p4.pCtx;
7292 
7293   /* If this function is inside of a trigger, the register array in aMem[]
7294   ** might change from one evaluation to the next.  The next block of code
7295   ** checks to see if the register array has changed, and if so it
7296   ** reinitializes the relavant parts of the sqlite3_context object */
7297   pOut = &aMem[pOp->p3];
7298   if( pCtx->pOut != pOut ){
7299     pCtx->pOut = pOut;
7300     for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
7301   }
7302 
7303   memAboutToChange(p, pOut);
7304 #ifdef SQLITE_DEBUG
7305   for(i=0; i<pCtx->argc; i++){
7306     assert( memIsValid(pCtx->argv[i]) );
7307     REGISTER_TRACE(pOp->p2+i, pCtx->argv[i]);
7308   }
7309 #endif
7310   MemSetTypeFlag(pOut, MEM_Null);
7311   assert( pCtx->isError==0 );
7312   (*pCtx->pFunc->xSFunc)(pCtx, pCtx->argc, pCtx->argv);/* IMP: R-24505-23230 */
7313 
7314   /* If the function returned an error, throw an exception */
7315   if( pCtx->isError ){
7316     if( pCtx->isError>0 ){
7317       sqlite3VdbeError(p, "%s", sqlite3_value_text(pOut));
7318       rc = pCtx->isError;
7319     }
7320     sqlite3VdbeDeleteAuxData(db, &p->pAuxData, pCtx->iOp, pOp->p1);
7321     pCtx->isError = 0;
7322     if( rc ) goto abort_due_to_error;
7323   }
7324 
7325   /* Copy the result of the function into register P3 */
7326   if( pOut->flags & (MEM_Str|MEM_Blob) ){
7327     sqlite3VdbeChangeEncoding(pOut, encoding);
7328     if( sqlite3VdbeMemTooBig(pOut) ) goto too_big;
7329   }
7330 
7331   REGISTER_TRACE(pOp->p3, pOut);
7332   UPDATE_MAX_BLOBSIZE(pOut);
7333   break;
7334 }
7335 
7336 /* Opcode: Trace P1 P2 * P4 *
7337 **
7338 ** Write P4 on the statement trace output if statement tracing is
7339 ** enabled.
7340 **
7341 ** Operand P1 must be 0x7fffffff and P2 must positive.
7342 */
7343 /* Opcode: Init P1 P2 P3 P4 *
7344 ** Synopsis: Start at P2
7345 **
7346 ** Programs contain a single instance of this opcode as the very first
7347 ** opcode.
7348 **
7349 ** If tracing is enabled (by the sqlite3_trace()) interface, then
7350 ** the UTF-8 string contained in P4 is emitted on the trace callback.
7351 ** Or if P4 is blank, use the string returned by sqlite3_sql().
7352 **
7353 ** If P2 is not zero, jump to instruction P2.
7354 **
7355 ** Increment the value of P1 so that OP_Once opcodes will jump the
7356 ** first time they are evaluated for this run.
7357 **
7358 ** If P3 is not zero, then it is an address to jump to if an SQLITE_CORRUPT
7359 ** error is encountered.
7360 */
7361 case OP_Trace:
7362 case OP_Init: {          /* jump */
7363   int i;
7364 #ifndef SQLITE_OMIT_TRACE
7365   char *zTrace;
7366 #endif
7367 
7368   /* If the P4 argument is not NULL, then it must be an SQL comment string.
7369   ** The "--" string is broken up to prevent false-positives with srcck1.c.
7370   **
7371   ** This assert() provides evidence for:
7372   ** EVIDENCE-OF: R-50676-09860 The callback can compute the same text that
7373   ** would have been returned by the legacy sqlite3_trace() interface by
7374   ** using the X argument when X begins with "--" and invoking
7375   ** sqlite3_expanded_sql(P) otherwise.
7376   */
7377   assert( pOp->p4.z==0 || strncmp(pOp->p4.z, "-" "- ", 3)==0 );
7378 
7379   /* OP_Init is always instruction 0 */
7380   assert( pOp==p->aOp || pOp->opcode==OP_Trace );
7381 
7382 #ifndef SQLITE_OMIT_TRACE
7383   if( (db->mTrace & (SQLITE_TRACE_STMT|SQLITE_TRACE_LEGACY))!=0
7384    && !p->doingRerun
7385    && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
7386   ){
7387 #ifndef SQLITE_OMIT_DEPRECATED
7388     if( db->mTrace & SQLITE_TRACE_LEGACY ){
7389       void (*x)(void*,const char*) = (void(*)(void*,const char*))db->xTrace;
7390       char *z = sqlite3VdbeExpandSql(p, zTrace);
7391       x(db->pTraceArg, z);
7392       sqlite3_free(z);
7393     }else
7394 #endif
7395     if( db->nVdbeExec>1 ){
7396       char *z = sqlite3MPrintf(db, "-- %s", zTrace);
7397       (void)db->xTrace(SQLITE_TRACE_STMT, db->pTraceArg, p, z);
7398       sqlite3DbFree(db, z);
7399     }else{
7400       (void)db->xTrace(SQLITE_TRACE_STMT, db->pTraceArg, p, zTrace);
7401     }
7402   }
7403 #ifdef SQLITE_USE_FCNTL_TRACE
7404   zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql);
7405   if( zTrace ){
7406     int j;
7407     for(j=0; j<db->nDb; j++){
7408       if( DbMaskTest(p->btreeMask, j)==0 ) continue;
7409       sqlite3_file_control(db, db->aDb[j].zDbSName, SQLITE_FCNTL_TRACE, zTrace);
7410     }
7411   }
7412 #endif /* SQLITE_USE_FCNTL_TRACE */
7413 #ifdef SQLITE_DEBUG
7414   if( (db->flags & SQLITE_SqlTrace)!=0
7415    && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
7416   ){
7417     sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
7418   }
7419 #endif /* SQLITE_DEBUG */
7420 #endif /* SQLITE_OMIT_TRACE */
7421   assert( pOp->p2>0 );
7422   if( pOp->p1>=sqlite3GlobalConfig.iOnceResetThreshold ){
7423     if( pOp->opcode==OP_Trace ) break;
7424     for(i=1; i<p->nOp; i++){
7425       if( p->aOp[i].opcode==OP_Once ) p->aOp[i].p1 = 0;
7426     }
7427     pOp->p1 = 0;
7428   }
7429   pOp->p1++;
7430   p->aCounter[SQLITE_STMTSTATUS_RUN]++;
7431   goto jump_to_p2;
7432 }
7433 
7434 #ifdef SQLITE_ENABLE_CURSOR_HINTS
7435 /* Opcode: CursorHint P1 * * P4 *
7436 **
7437 ** Provide a hint to cursor P1 that it only needs to return rows that
7438 ** satisfy the Expr in P4.  TK_REGISTER terms in the P4 expression refer
7439 ** to values currently held in registers.  TK_COLUMN terms in the P4
7440 ** expression refer to columns in the b-tree to which cursor P1 is pointing.
7441 */
7442 case OP_CursorHint: {
7443   VdbeCursor *pC;
7444 
7445   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
7446   assert( pOp->p4type==P4_EXPR );
7447   pC = p->apCsr[pOp->p1];
7448   if( pC ){
7449     assert( pC->eCurType==CURTYPE_BTREE );
7450     sqlite3BtreeCursorHint(pC->uc.pCursor, BTREE_HINT_RANGE,
7451                            pOp->p4.pExpr, aMem);
7452   }
7453   break;
7454 }
7455 #endif /* SQLITE_ENABLE_CURSOR_HINTS */
7456 
7457 #ifdef SQLITE_DEBUG
7458 /* Opcode:  Abortable   * * * * *
7459 **
7460 ** Verify that an Abort can happen.  Assert if an Abort at this point
7461 ** might cause database corruption.  This opcode only appears in debugging
7462 ** builds.
7463 **
7464 ** An Abort is safe if either there have been no writes, or if there is
7465 ** an active statement journal.
7466 */
7467 case OP_Abortable: {
7468   sqlite3VdbeAssertAbortable(p);
7469   break;
7470 }
7471 #endif
7472 
7473 /* Opcode: Noop * * * * *
7474 **
7475 ** Do nothing.  This instruction is often useful as a jump
7476 ** destination.
7477 */
7478 /*
7479 ** The magic Explain opcode are only inserted when explain==2 (which
7480 ** is to say when the EXPLAIN QUERY PLAN syntax is used.)
7481 ** This opcode records information from the optimizer.  It is the
7482 ** the same as a no-op.  This opcodesnever appears in a real VM program.
7483 */
7484 default: {          /* This is really OP_Noop, OP_Explain */
7485   assert( pOp->opcode==OP_Noop || pOp->opcode==OP_Explain );
7486 
7487   break;
7488 }
7489 
7490 /*****************************************************************************
7491 ** The cases of the switch statement above this line should all be indented
7492 ** by 6 spaces.  But the left-most 6 spaces have been removed to improve the
7493 ** readability.  From this point on down, the normal indentation rules are
7494 ** restored.
7495 *****************************************************************************/
7496     }
7497 
7498 #ifdef VDBE_PROFILE
7499     {
7500       u64 endTime = sqlite3NProfileCnt ? sqlite3NProfileCnt : sqlite3Hwtime();
7501       if( endTime>start ) pOrigOp->cycles += endTime - start;
7502       pOrigOp->cnt++;
7503     }
7504 #endif
7505 
7506     /* The following code adds nothing to the actual functionality
7507     ** of the program.  It is only here for testing and debugging.
7508     ** On the other hand, it does burn CPU cycles every time through
7509     ** the evaluator loop.  So we can leave it out when NDEBUG is defined.
7510     */
7511 #ifndef NDEBUG
7512     assert( pOp>=&aOp[-1] && pOp<&aOp[p->nOp-1] );
7513 
7514 #ifdef SQLITE_DEBUG
7515     if( db->flags & SQLITE_VdbeTrace ){
7516       u8 opProperty = sqlite3OpcodeProperty[pOrigOp->opcode];
7517       if( rc!=0 ) printf("rc=%d\n",rc);
7518       if( opProperty & (OPFLG_OUT2) ){
7519         registerTrace(pOrigOp->p2, &aMem[pOrigOp->p2]);
7520       }
7521       if( opProperty & OPFLG_OUT3 ){
7522         registerTrace(pOrigOp->p3, &aMem[pOrigOp->p3]);
7523       }
7524     }
7525 #endif  /* SQLITE_DEBUG */
7526 #endif  /* NDEBUG */
7527   }  /* The end of the for(;;) loop the loops through opcodes */
7528 
7529   /* If we reach this point, it means that execution is finished with
7530   ** an error of some kind.
7531   */
7532 abort_due_to_error:
7533   if( db->mallocFailed ) rc = SQLITE_NOMEM_BKPT;
7534   assert( rc );
7535   if( p->zErrMsg==0 && rc!=SQLITE_IOERR_NOMEM ){
7536     sqlite3VdbeError(p, "%s", sqlite3ErrStr(rc));
7537   }
7538   p->rc = rc;
7539   sqlite3SystemError(db, rc);
7540   testcase( sqlite3GlobalConfig.xLog!=0 );
7541   sqlite3_log(rc, "statement aborts at %d: [%s] %s",
7542                    (int)(pOp - aOp), p->zSql, p->zErrMsg);
7543   sqlite3VdbeHalt(p);
7544   if( rc==SQLITE_IOERR_NOMEM ) sqlite3OomFault(db);
7545   rc = SQLITE_ERROR;
7546   if( resetSchemaOnFault>0 ){
7547     sqlite3ResetOneSchema(db, resetSchemaOnFault-1);
7548   }
7549 
7550   /* This is the only way out of this procedure.  We have to
7551   ** release the mutexes on btrees that were acquired at the
7552   ** top. */
7553 vdbe_return:
7554   testcase( nVmStep>0 );
7555   p->aCounter[SQLITE_STMTSTATUS_VM_STEP] += (int)nVmStep;
7556   sqlite3VdbeLeave(p);
7557   assert( rc!=SQLITE_OK || nExtraDelete==0
7558        || sqlite3_strlike("DELETE%",p->zSql,0)!=0
7559   );
7560   return rc;
7561 
7562   /* Jump to here if a string or blob larger than SQLITE_MAX_LENGTH
7563   ** is encountered.
7564   */
7565 too_big:
7566   sqlite3VdbeError(p, "string or blob too big");
7567   rc = SQLITE_TOOBIG;
7568   goto abort_due_to_error;
7569 
7570   /* Jump to here if a malloc() fails.
7571   */
7572 no_mem:
7573   sqlite3OomFault(db);
7574   sqlite3VdbeError(p, "out of memory");
7575   rc = SQLITE_NOMEM_BKPT;
7576   goto abort_due_to_error;
7577 
7578   /* Jump to here if the sqlite3_interrupt() API sets the interrupt
7579   ** flag.
7580   */
7581 abort_due_to_interrupt:
7582   assert( db->u1.isInterrupted );
7583   rc = db->mallocFailed ? SQLITE_NOMEM_BKPT : SQLITE_INTERRUPT;
7584   p->rc = rc;
7585   sqlite3VdbeError(p, "%s", sqlite3ErrStr(rc));
7586   goto abort_due_to_error;
7587 }
7588