xref: /sqlite-3.40.0/src/vdbeapi.c (revision c9373e86)
1 /*
2 ** 2004 May 26
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 **
13 ** This file contains code use to implement APIs that are part of the
14 ** VDBE.
15 */
16 #include "sqliteInt.h"
17 #include "vdbeInt.h"
18 
19 #ifndef SQLITE_OMIT_DEPRECATED
20 /*
21 ** Return TRUE (non-zero) of the statement supplied as an argument needs
22 ** to be recompiled.  A statement needs to be recompiled whenever the
23 ** execution environment changes in a way that would alter the program
24 ** that sqlite3_prepare() generates.  For example, if new functions or
25 ** collating sequences are registered or if an authorizer function is
26 ** added or changed.
27 */
28 int sqlite3_expired(sqlite3_stmt *pStmt){
29   Vdbe *p = (Vdbe*)pStmt;
30   return p==0 || p->expired;
31 }
32 #endif
33 
34 /*
35 ** Check on a Vdbe to make sure it has not been finalized.  Log
36 ** an error and return true if it has been finalized (or is otherwise
37 ** invalid).  Return false if it is ok.
38 */
39 static int vdbeSafety(Vdbe *p){
40   if( p->db==0 ){
41     sqlite3_log(SQLITE_MISUSE, "API called with finalized prepared statement");
42     return 1;
43   }else{
44     return 0;
45   }
46 }
47 static int vdbeSafetyNotNull(Vdbe *p){
48   if( p==0 ){
49     sqlite3_log(SQLITE_MISUSE, "API called with NULL prepared statement");
50     return 1;
51   }else{
52     return vdbeSafety(p);
53   }
54 }
55 
56 #ifndef SQLITE_OMIT_TRACE
57 /*
58 ** Invoke the profile callback.  This routine is only called if we already
59 ** know that the profile callback is defined and needs to be invoked.
60 */
61 static SQLITE_NOINLINE void invokeProfileCallback(sqlite3 *db, Vdbe *p){
62   sqlite3_int64 iNow;
63   sqlite3_int64 iElapse;
64   assert( p->startTime>0 );
65   assert( (db->mTrace & (SQLITE_TRACE_PROFILE|SQLITE_TRACE_XPROFILE))!=0 );
66   assert( db->init.busy==0 );
67   assert( p->zSql!=0 );
68   sqlite3OsCurrentTimeInt64(db->pVfs, &iNow);
69   iElapse = (iNow - p->startTime)*1000000;
70 #ifndef SQLITE_OMIT_DEPRECATED
71   if( db->xProfile ){
72     db->xProfile(db->pProfileArg, p->zSql, iElapse);
73   }
74 #endif
75   if( db->mTrace & SQLITE_TRACE_PROFILE ){
76     db->trace.xV2(SQLITE_TRACE_PROFILE, db->pTraceArg, p, (void*)&iElapse);
77   }
78   p->startTime = 0;
79 }
80 /*
81 ** The checkProfileCallback(DB,P) macro checks to see if a profile callback
82 ** is needed, and it invokes the callback if it is needed.
83 */
84 # define checkProfileCallback(DB,P) \
85    if( ((P)->startTime)>0 ){ invokeProfileCallback(DB,P); }
86 #else
87 # define checkProfileCallback(DB,P)  /*no-op*/
88 #endif
89 
90 /*
91 ** The following routine destroys a virtual machine that is created by
92 ** the sqlite3_compile() routine. The integer returned is an SQLITE_
93 ** success/failure code that describes the result of executing the virtual
94 ** machine.
95 **
96 ** This routine sets the error code and string returned by
97 ** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
98 */
99 int sqlite3_finalize(sqlite3_stmt *pStmt){
100   int rc;
101   if( pStmt==0 ){
102     /* IMPLEMENTATION-OF: R-57228-12904 Invoking sqlite3_finalize() on a NULL
103     ** pointer is a harmless no-op. */
104     rc = SQLITE_OK;
105   }else{
106     Vdbe *v = (Vdbe*)pStmt;
107     sqlite3 *db = v->db;
108     if( vdbeSafety(v) ) return SQLITE_MISUSE_BKPT;
109     sqlite3_mutex_enter(db->mutex);
110     checkProfileCallback(db, v);
111     rc = sqlite3VdbeFinalize(v);
112     rc = sqlite3ApiExit(db, rc);
113     sqlite3LeaveMutexAndCloseZombie(db);
114   }
115   return rc;
116 }
117 
118 /*
119 ** Terminate the current execution of an SQL statement and reset it
120 ** back to its starting state so that it can be reused. A success code from
121 ** the prior execution is returned.
122 **
123 ** This routine sets the error code and string returned by
124 ** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
125 */
126 int sqlite3_reset(sqlite3_stmt *pStmt){
127   int rc;
128   if( pStmt==0 ){
129     rc = SQLITE_OK;
130   }else{
131     Vdbe *v = (Vdbe*)pStmt;
132     sqlite3 *db = v->db;
133     sqlite3_mutex_enter(db->mutex);
134     checkProfileCallback(db, v);
135     rc = sqlite3VdbeReset(v);
136     sqlite3VdbeRewind(v);
137     assert( (rc & (db->errMask))==rc );
138     rc = sqlite3ApiExit(db, rc);
139     sqlite3_mutex_leave(db->mutex);
140   }
141   return rc;
142 }
143 
144 /*
145 ** Set all the parameters in the compiled SQL statement to NULL.
146 */
147 int sqlite3_clear_bindings(sqlite3_stmt *pStmt){
148   int i;
149   int rc = SQLITE_OK;
150   Vdbe *p = (Vdbe*)pStmt;
151 #if SQLITE_THREADSAFE
152   sqlite3_mutex *mutex = ((Vdbe*)pStmt)->db->mutex;
153 #endif
154   sqlite3_mutex_enter(mutex);
155   for(i=0; i<p->nVar; i++){
156     sqlite3VdbeMemRelease(&p->aVar[i]);
157     p->aVar[i].flags = MEM_Null;
158   }
159   assert( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || p->expmask==0 );
160   if( p->expmask ){
161     p->expired = 1;
162   }
163   sqlite3_mutex_leave(mutex);
164   return rc;
165 }
166 
167 
168 /**************************** sqlite3_value_  *******************************
169 ** The following routines extract information from a Mem or sqlite3_value
170 ** structure.
171 */
172 const void *sqlite3_value_blob(sqlite3_value *pVal){
173   Mem *p = (Mem*)pVal;
174   if( p->flags & (MEM_Blob|MEM_Str) ){
175     if( ExpandBlob(p)!=SQLITE_OK ){
176       assert( p->flags==MEM_Null && p->z==0 );
177       return 0;
178     }
179     p->flags |= MEM_Blob;
180     return p->n ? p->z : 0;
181   }else{
182     return sqlite3_value_text(pVal);
183   }
184 }
185 int sqlite3_value_bytes(sqlite3_value *pVal){
186   return sqlite3ValueBytes(pVal, SQLITE_UTF8);
187 }
188 int sqlite3_value_bytes16(sqlite3_value *pVal){
189   return sqlite3ValueBytes(pVal, SQLITE_UTF16NATIVE);
190 }
191 double sqlite3_value_double(sqlite3_value *pVal){
192   return sqlite3VdbeRealValue((Mem*)pVal);
193 }
194 int sqlite3_value_int(sqlite3_value *pVal){
195   return (int)sqlite3VdbeIntValue((Mem*)pVal);
196 }
197 sqlite_int64 sqlite3_value_int64(sqlite3_value *pVal){
198   return sqlite3VdbeIntValue((Mem*)pVal);
199 }
200 unsigned int sqlite3_value_subtype(sqlite3_value *pVal){
201   Mem *pMem = (Mem*)pVal;
202   return ((pMem->flags & MEM_Subtype) ? pMem->eSubtype : 0);
203 }
204 void *sqlite3_value_pointer(sqlite3_value *pVal, const char *zPType){
205   Mem *p = (Mem*)pVal;
206   if( (p->flags&(MEM_TypeMask|MEM_Term|MEM_Subtype)) ==
207                  (MEM_Null|MEM_Term|MEM_Subtype)
208    && zPType!=0
209    && p->eSubtype=='p'
210    && strcmp(p->u.zPType, zPType)==0
211   ){
212     return (void*)p->z;
213   }else{
214     return 0;
215   }
216 }
217 const unsigned char *sqlite3_value_text(sqlite3_value *pVal){
218   return (const unsigned char *)sqlite3ValueText(pVal, SQLITE_UTF8);
219 }
220 #ifndef SQLITE_OMIT_UTF16
221 const void *sqlite3_value_text16(sqlite3_value* pVal){
222   return sqlite3ValueText(pVal, SQLITE_UTF16NATIVE);
223 }
224 const void *sqlite3_value_text16be(sqlite3_value *pVal){
225   return sqlite3ValueText(pVal, SQLITE_UTF16BE);
226 }
227 const void *sqlite3_value_text16le(sqlite3_value *pVal){
228   return sqlite3ValueText(pVal, SQLITE_UTF16LE);
229 }
230 #endif /* SQLITE_OMIT_UTF16 */
231 /* EVIDENCE-OF: R-12793-43283 Every value in SQLite has one of five
232 ** fundamental datatypes: 64-bit signed integer 64-bit IEEE floating
233 ** point number string BLOB NULL
234 */
235 int sqlite3_value_type(sqlite3_value* pVal){
236   static const u8 aType[] = {
237      SQLITE_BLOB,     /* 0x00 (not possible) */
238      SQLITE_NULL,     /* 0x01 NULL */
239      SQLITE_TEXT,     /* 0x02 TEXT */
240      SQLITE_NULL,     /* 0x03 (not possible) */
241      SQLITE_INTEGER,  /* 0x04 INTEGER */
242      SQLITE_NULL,     /* 0x05 (not possible) */
243      SQLITE_INTEGER,  /* 0x06 INTEGER + TEXT */
244      SQLITE_NULL,     /* 0x07 (not possible) */
245      SQLITE_FLOAT,    /* 0x08 FLOAT */
246      SQLITE_NULL,     /* 0x09 (not possible) */
247      SQLITE_FLOAT,    /* 0x0a FLOAT + TEXT */
248      SQLITE_NULL,     /* 0x0b (not possible) */
249      SQLITE_INTEGER,  /* 0x0c (not possible) */
250      SQLITE_NULL,     /* 0x0d (not possible) */
251      SQLITE_INTEGER,  /* 0x0e (not possible) */
252      SQLITE_NULL,     /* 0x0f (not possible) */
253      SQLITE_BLOB,     /* 0x10 BLOB */
254      SQLITE_NULL,     /* 0x11 (not possible) */
255      SQLITE_TEXT,     /* 0x12 (not possible) */
256      SQLITE_NULL,     /* 0x13 (not possible) */
257      SQLITE_INTEGER,  /* 0x14 INTEGER + BLOB */
258      SQLITE_NULL,     /* 0x15 (not possible) */
259      SQLITE_INTEGER,  /* 0x16 (not possible) */
260      SQLITE_NULL,     /* 0x17 (not possible) */
261      SQLITE_FLOAT,    /* 0x18 FLOAT + BLOB */
262      SQLITE_NULL,     /* 0x19 (not possible) */
263      SQLITE_FLOAT,    /* 0x1a (not possible) */
264      SQLITE_NULL,     /* 0x1b (not possible) */
265      SQLITE_INTEGER,  /* 0x1c (not possible) */
266      SQLITE_NULL,     /* 0x1d (not possible) */
267      SQLITE_INTEGER,  /* 0x1e (not possible) */
268      SQLITE_NULL,     /* 0x1f (not possible) */
269      SQLITE_FLOAT,    /* 0x20 INTREAL */
270      SQLITE_NULL,     /* 0x21 (not possible) */
271      SQLITE_TEXT,     /* 0x22 INTREAL + TEXT */
272      SQLITE_NULL,     /* 0x23 (not possible) */
273      SQLITE_FLOAT,    /* 0x24 (not possible) */
274      SQLITE_NULL,     /* 0x25 (not possible) */
275      SQLITE_FLOAT,    /* 0x26 (not possible) */
276      SQLITE_NULL,     /* 0x27 (not possible) */
277      SQLITE_FLOAT,    /* 0x28 (not possible) */
278      SQLITE_NULL,     /* 0x29 (not possible) */
279      SQLITE_FLOAT,    /* 0x2a (not possible) */
280      SQLITE_NULL,     /* 0x2b (not possible) */
281      SQLITE_FLOAT,    /* 0x2c (not possible) */
282      SQLITE_NULL,     /* 0x2d (not possible) */
283      SQLITE_FLOAT,    /* 0x2e (not possible) */
284      SQLITE_NULL,     /* 0x2f (not possible) */
285      SQLITE_BLOB,     /* 0x30 (not possible) */
286      SQLITE_NULL,     /* 0x31 (not possible) */
287      SQLITE_TEXT,     /* 0x32 (not possible) */
288      SQLITE_NULL,     /* 0x33 (not possible) */
289      SQLITE_FLOAT,    /* 0x34 (not possible) */
290      SQLITE_NULL,     /* 0x35 (not possible) */
291      SQLITE_FLOAT,    /* 0x36 (not possible) */
292      SQLITE_NULL,     /* 0x37 (not possible) */
293      SQLITE_FLOAT,    /* 0x38 (not possible) */
294      SQLITE_NULL,     /* 0x39 (not possible) */
295      SQLITE_FLOAT,    /* 0x3a (not possible) */
296      SQLITE_NULL,     /* 0x3b (not possible) */
297      SQLITE_FLOAT,    /* 0x3c (not possible) */
298      SQLITE_NULL,     /* 0x3d (not possible) */
299      SQLITE_FLOAT,    /* 0x3e (not possible) */
300      SQLITE_NULL,     /* 0x3f (not possible) */
301   };
302 #ifdef SQLITE_DEBUG
303   {
304     int eType = SQLITE_BLOB;
305     if( pVal->flags & MEM_Null ){
306       eType = SQLITE_NULL;
307     }else if( pVal->flags & (MEM_Real|MEM_IntReal) ){
308       eType = SQLITE_FLOAT;
309     }else if( pVal->flags & MEM_Int ){
310       eType = SQLITE_INTEGER;
311     }else if( pVal->flags & MEM_Str ){
312       eType = SQLITE_TEXT;
313     }
314     assert( eType == aType[pVal->flags&MEM_AffMask] );
315   }
316 #endif
317   return aType[pVal->flags&MEM_AffMask];
318 }
319 
320 /* Return true if a parameter to xUpdate represents an unchanged column */
321 int sqlite3_value_nochange(sqlite3_value *pVal){
322   return (pVal->flags&(MEM_Null|MEM_Zero))==(MEM_Null|MEM_Zero);
323 }
324 
325 /* Return true if a parameter value originated from an sqlite3_bind() */
326 int sqlite3_value_frombind(sqlite3_value *pVal){
327   return (pVal->flags&MEM_FromBind)!=0;
328 }
329 
330 /* Make a copy of an sqlite3_value object
331 */
332 sqlite3_value *sqlite3_value_dup(const sqlite3_value *pOrig){
333   sqlite3_value *pNew;
334   if( pOrig==0 ) return 0;
335   pNew = sqlite3_malloc( sizeof(*pNew) );
336   if( pNew==0 ) return 0;
337   memset(pNew, 0, sizeof(*pNew));
338   memcpy(pNew, pOrig, MEMCELLSIZE);
339   pNew->flags &= ~MEM_Dyn;
340   pNew->db = 0;
341   if( pNew->flags&(MEM_Str|MEM_Blob) ){
342     pNew->flags &= ~(MEM_Static|MEM_Dyn);
343     pNew->flags |= MEM_Ephem;
344     if( sqlite3VdbeMemMakeWriteable(pNew)!=SQLITE_OK ){
345       sqlite3ValueFree(pNew);
346       pNew = 0;
347     }
348   }
349   return pNew;
350 }
351 
352 /* Destroy an sqlite3_value object previously obtained from
353 ** sqlite3_value_dup().
354 */
355 void sqlite3_value_free(sqlite3_value *pOld){
356   sqlite3ValueFree(pOld);
357 }
358 
359 
360 /**************************** sqlite3_result_  *******************************
361 ** The following routines are used by user-defined functions to specify
362 ** the function result.
363 **
364 ** The setStrOrError() function calls sqlite3VdbeMemSetStr() to store the
365 ** result as a string or blob.  Appropriate errors are set if the string/blob
366 ** is too big or if an OOM occurs.
367 **
368 ** The invokeValueDestructor(P,X) routine invokes destructor function X()
369 ** on value P is not going to be used and need to be destroyed.
370 */
371 static void setResultStrOrError(
372   sqlite3_context *pCtx,  /* Function context */
373   const char *z,          /* String pointer */
374   int n,                  /* Bytes in string, or negative */
375   u8 enc,                 /* Encoding of z.  0 for BLOBs */
376   void (*xDel)(void*)     /* Destructor function */
377 ){
378   int rc = sqlite3VdbeMemSetStr(pCtx->pOut, z, n, enc, xDel);
379   if( rc ){
380     if( rc==SQLITE_TOOBIG ){
381       sqlite3_result_error_toobig(pCtx);
382     }else{
383       /* The only errors possible from sqlite3VdbeMemSetStr are
384       ** SQLITE_TOOBIG and SQLITE_NOMEM */
385       assert( rc==SQLITE_NOMEM );
386       sqlite3_result_error_nomem(pCtx);
387     }
388   }
389 }
390 static int invokeValueDestructor(
391   const void *p,             /* Value to destroy */
392   void (*xDel)(void*),       /* The destructor */
393   sqlite3_context *pCtx      /* Set a SQLITE_TOOBIG error if no NULL */
394 ){
395   assert( xDel!=SQLITE_DYNAMIC );
396   if( xDel==0 ){
397     /* noop */
398   }else if( xDel==SQLITE_TRANSIENT ){
399     /* noop */
400   }else{
401     xDel((void*)p);
402   }
403   sqlite3_result_error_toobig(pCtx);
404   return SQLITE_TOOBIG;
405 }
406 void sqlite3_result_blob(
407   sqlite3_context *pCtx,
408   const void *z,
409   int n,
410   void (*xDel)(void *)
411 ){
412   assert( n>=0 );
413   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
414   setResultStrOrError(pCtx, z, n, 0, xDel);
415 }
416 void sqlite3_result_blob64(
417   sqlite3_context *pCtx,
418   const void *z,
419   sqlite3_uint64 n,
420   void (*xDel)(void *)
421 ){
422   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
423   assert( xDel!=SQLITE_DYNAMIC );
424   if( n>0x7fffffff ){
425     (void)invokeValueDestructor(z, xDel, pCtx);
426   }else{
427     setResultStrOrError(pCtx, z, (int)n, 0, xDel);
428   }
429 }
430 void sqlite3_result_double(sqlite3_context *pCtx, double rVal){
431   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
432   sqlite3VdbeMemSetDouble(pCtx->pOut, rVal);
433 }
434 void sqlite3_result_error(sqlite3_context *pCtx, const char *z, int n){
435   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
436   pCtx->isError = SQLITE_ERROR;
437   sqlite3VdbeMemSetStr(pCtx->pOut, z, n, SQLITE_UTF8, SQLITE_TRANSIENT);
438 }
439 #ifndef SQLITE_OMIT_UTF16
440 void sqlite3_result_error16(sqlite3_context *pCtx, const void *z, int n){
441   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
442   pCtx->isError = SQLITE_ERROR;
443   sqlite3VdbeMemSetStr(pCtx->pOut, z, n, SQLITE_UTF16NATIVE, SQLITE_TRANSIENT);
444 }
445 #endif
446 void sqlite3_result_int(sqlite3_context *pCtx, int iVal){
447   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
448   sqlite3VdbeMemSetInt64(pCtx->pOut, (i64)iVal);
449 }
450 void sqlite3_result_int64(sqlite3_context *pCtx, i64 iVal){
451   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
452   sqlite3VdbeMemSetInt64(pCtx->pOut, iVal);
453 }
454 void sqlite3_result_null(sqlite3_context *pCtx){
455   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
456   sqlite3VdbeMemSetNull(pCtx->pOut);
457 }
458 void sqlite3_result_pointer(
459   sqlite3_context *pCtx,
460   void *pPtr,
461   const char *zPType,
462   void (*xDestructor)(void*)
463 ){
464   Mem *pOut = pCtx->pOut;
465   assert( sqlite3_mutex_held(pOut->db->mutex) );
466   sqlite3VdbeMemRelease(pOut);
467   pOut->flags = MEM_Null;
468   sqlite3VdbeMemSetPointer(pOut, pPtr, zPType, xDestructor);
469 }
470 void sqlite3_result_subtype(sqlite3_context *pCtx, unsigned int eSubtype){
471   Mem *pOut = pCtx->pOut;
472   assert( sqlite3_mutex_held(pOut->db->mutex) );
473   pOut->eSubtype = eSubtype & 0xff;
474   pOut->flags |= MEM_Subtype;
475 }
476 void sqlite3_result_text(
477   sqlite3_context *pCtx,
478   const char *z,
479   int n,
480   void (*xDel)(void *)
481 ){
482   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
483   setResultStrOrError(pCtx, z, n, SQLITE_UTF8, xDel);
484 }
485 void sqlite3_result_text64(
486   sqlite3_context *pCtx,
487   const char *z,
488   sqlite3_uint64 n,
489   void (*xDel)(void *),
490   unsigned char enc
491 ){
492   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
493   assert( xDel!=SQLITE_DYNAMIC );
494   if( enc==SQLITE_UTF16 ) enc = SQLITE_UTF16NATIVE;
495   if( n>0x7fffffff ){
496     (void)invokeValueDestructor(z, xDel, pCtx);
497   }else{
498     setResultStrOrError(pCtx, z, (int)n, enc, xDel);
499   }
500 }
501 #ifndef SQLITE_OMIT_UTF16
502 void sqlite3_result_text16(
503   sqlite3_context *pCtx,
504   const void *z,
505   int n,
506   void (*xDel)(void *)
507 ){
508   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
509   setResultStrOrError(pCtx, z, n, SQLITE_UTF16NATIVE, xDel);
510 }
511 void sqlite3_result_text16be(
512   sqlite3_context *pCtx,
513   const void *z,
514   int n,
515   void (*xDel)(void *)
516 ){
517   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
518   setResultStrOrError(pCtx, z, n, SQLITE_UTF16BE, xDel);
519 }
520 void sqlite3_result_text16le(
521   sqlite3_context *pCtx,
522   const void *z,
523   int n,
524   void (*xDel)(void *)
525 ){
526   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
527   setResultStrOrError(pCtx, z, n, SQLITE_UTF16LE, xDel);
528 }
529 #endif /* SQLITE_OMIT_UTF16 */
530 void sqlite3_result_value(sqlite3_context *pCtx, sqlite3_value *pValue){
531   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
532   sqlite3VdbeMemCopy(pCtx->pOut, pValue);
533 }
534 void sqlite3_result_zeroblob(sqlite3_context *pCtx, int n){
535   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
536   sqlite3VdbeMemSetZeroBlob(pCtx->pOut, n);
537 }
538 int sqlite3_result_zeroblob64(sqlite3_context *pCtx, u64 n){
539   Mem *pOut = pCtx->pOut;
540   assert( sqlite3_mutex_held(pOut->db->mutex) );
541   if( n>(u64)pOut->db->aLimit[SQLITE_LIMIT_LENGTH] ){
542     return SQLITE_TOOBIG;
543   }
544 #ifndef SQLITE_OMIT_INCRBLOB
545   sqlite3VdbeMemSetZeroBlob(pCtx->pOut, (int)n);
546   return SQLITE_OK;
547 #else
548   return sqlite3VdbeMemSetZeroBlob(pCtx->pOut, (int)n);
549 #endif
550 }
551 void sqlite3_result_error_code(sqlite3_context *pCtx, int errCode){
552   pCtx->isError = errCode ? errCode : -1;
553 #ifdef SQLITE_DEBUG
554   if( pCtx->pVdbe ) pCtx->pVdbe->rcApp = errCode;
555 #endif
556   if( pCtx->pOut->flags & MEM_Null ){
557     sqlite3VdbeMemSetStr(pCtx->pOut, sqlite3ErrStr(errCode), -1,
558                          SQLITE_UTF8, SQLITE_STATIC);
559   }
560 }
561 
562 /* Force an SQLITE_TOOBIG error. */
563 void sqlite3_result_error_toobig(sqlite3_context *pCtx){
564   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
565   pCtx->isError = SQLITE_TOOBIG;
566   sqlite3VdbeMemSetStr(pCtx->pOut, "string or blob too big", -1,
567                        SQLITE_UTF8, SQLITE_STATIC);
568 }
569 
570 /* An SQLITE_NOMEM error. */
571 void sqlite3_result_error_nomem(sqlite3_context *pCtx){
572   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
573   sqlite3VdbeMemSetNull(pCtx->pOut);
574   pCtx->isError = SQLITE_NOMEM_BKPT;
575   sqlite3OomFault(pCtx->pOut->db);
576 }
577 
578 #ifndef SQLITE_UNTESTABLE
579 /* Force the INT64 value currently stored as the result to be
580 ** a MEM_IntReal value.  See the SQLITE_TESTCTRL_RESULT_INTREAL
581 ** test-control.
582 */
583 void sqlite3ResultIntReal(sqlite3_context *pCtx){
584   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
585   if( pCtx->pOut->flags & MEM_Int ){
586     pCtx->pOut->flags &= ~MEM_Int;
587     pCtx->pOut->flags |= MEM_IntReal;
588   }
589 }
590 #endif
591 
592 
593 /*
594 ** This function is called after a transaction has been committed. It
595 ** invokes callbacks registered with sqlite3_wal_hook() as required.
596 */
597 static int doWalCallbacks(sqlite3 *db){
598   int rc = SQLITE_OK;
599 #ifndef SQLITE_OMIT_WAL
600   int i;
601   for(i=0; i<db->nDb; i++){
602     Btree *pBt = db->aDb[i].pBt;
603     if( pBt ){
604       int nEntry;
605       sqlite3BtreeEnter(pBt);
606       nEntry = sqlite3PagerWalCallback(sqlite3BtreePager(pBt));
607       sqlite3BtreeLeave(pBt);
608       if( nEntry>0 && db->xWalCallback && rc==SQLITE_OK ){
609         rc = db->xWalCallback(db->pWalArg, db, db->aDb[i].zDbSName, nEntry);
610       }
611     }
612   }
613 #endif
614   return rc;
615 }
616 
617 
618 /*
619 ** Execute the statement pStmt, either until a row of data is ready, the
620 ** statement is completely executed or an error occurs.
621 **
622 ** This routine implements the bulk of the logic behind the sqlite_step()
623 ** API.  The only thing omitted is the automatic recompile if a
624 ** schema change has occurred.  That detail is handled by the
625 ** outer sqlite3_step() wrapper procedure.
626 */
627 static int sqlite3Step(Vdbe *p){
628   sqlite3 *db;
629   int rc;
630 
631   assert(p);
632   if( p->iVdbeMagic!=VDBE_MAGIC_RUN ){
633     /* We used to require that sqlite3_reset() be called before retrying
634     ** sqlite3_step() after any error or after SQLITE_DONE.  But beginning
635     ** with version 3.7.0, we changed this so that sqlite3_reset() would
636     ** be called automatically instead of throwing the SQLITE_MISUSE error.
637     ** This "automatic-reset" change is not technically an incompatibility,
638     ** since any application that receives an SQLITE_MISUSE is broken by
639     ** definition.
640     **
641     ** Nevertheless, some published applications that were originally written
642     ** for version 3.6.23 or earlier do in fact depend on SQLITE_MISUSE
643     ** returns, and those were broken by the automatic-reset change.  As a
644     ** a work-around, the SQLITE_OMIT_AUTORESET compile-time restores the
645     ** legacy behavior of returning SQLITE_MISUSE for cases where the
646     ** previous sqlite3_step() returned something other than a SQLITE_LOCKED
647     ** or SQLITE_BUSY error.
648     */
649 #ifdef SQLITE_OMIT_AUTORESET
650     if( (rc = p->rc&0xff)==SQLITE_BUSY || rc==SQLITE_LOCKED ){
651       sqlite3_reset((sqlite3_stmt*)p);
652     }else{
653       return SQLITE_MISUSE_BKPT;
654     }
655 #else
656     sqlite3_reset((sqlite3_stmt*)p);
657 #endif
658   }
659 
660   /* Check that malloc() has not failed. If it has, return early. */
661   db = p->db;
662   if( db->mallocFailed ){
663     p->rc = SQLITE_NOMEM;
664     return SQLITE_NOMEM_BKPT;
665   }
666 
667   if( p->pc<0 && p->expired ){
668     p->rc = SQLITE_SCHEMA;
669     rc = SQLITE_ERROR;
670     if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ){
671       /* If this statement was prepared using saved SQL and an
672       ** error has occurred, then return the error code in p->rc to the
673       ** caller. Set the error code in the database handle to the same value.
674       */
675       rc = sqlite3VdbeTransferError(p);
676     }
677     goto end_of_step;
678   }
679   if( p->pc<0 ){
680     /* If there are no other statements currently running, then
681     ** reset the interrupt flag.  This prevents a call to sqlite3_interrupt
682     ** from interrupting a statement that has not yet started.
683     */
684     if( db->nVdbeActive==0 ){
685       AtomicStore(&db->u1.isInterrupted, 0);
686     }
687 
688     assert( db->nVdbeWrite>0 || db->autoCommit==0
689         || (db->nDeferredCons==0 && db->nDeferredImmCons==0)
690     );
691 
692 #ifndef SQLITE_OMIT_TRACE
693     if( (db->mTrace & (SQLITE_TRACE_PROFILE|SQLITE_TRACE_XPROFILE))!=0
694         && !db->init.busy && p->zSql ){
695       sqlite3OsCurrentTimeInt64(db->pVfs, &p->startTime);
696     }else{
697       assert( p->startTime==0 );
698     }
699 #endif
700 
701     db->nVdbeActive++;
702     if( p->readOnly==0 ) db->nVdbeWrite++;
703     if( p->bIsReader ) db->nVdbeRead++;
704     p->pc = 0;
705   }
706 #ifdef SQLITE_DEBUG
707   p->rcApp = SQLITE_OK;
708 #endif
709 #ifndef SQLITE_OMIT_EXPLAIN
710   if( p->explain ){
711     rc = sqlite3VdbeList(p);
712   }else
713 #endif /* SQLITE_OMIT_EXPLAIN */
714   {
715     db->nVdbeExec++;
716     rc = sqlite3VdbeExec(p);
717     db->nVdbeExec--;
718   }
719 
720   if( rc!=SQLITE_ROW ){
721 #ifndef SQLITE_OMIT_TRACE
722     /* If the statement completed successfully, invoke the profile callback */
723     checkProfileCallback(db, p);
724 #endif
725 
726     if( rc==SQLITE_DONE && db->autoCommit ){
727       assert( p->rc==SQLITE_OK );
728       p->rc = doWalCallbacks(db);
729       if( p->rc!=SQLITE_OK ){
730         rc = SQLITE_ERROR;
731       }
732     }else if( rc!=SQLITE_DONE && (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ){
733       /* If this statement was prepared using saved SQL and an
734       ** error has occurred, then return the error code in p->rc to the
735       ** caller. Set the error code in the database handle to the same value.
736       */
737       rc = sqlite3VdbeTransferError(p);
738     }
739   }
740 
741   db->errCode = rc;
742   if( SQLITE_NOMEM==sqlite3ApiExit(p->db, p->rc) ){
743     p->rc = SQLITE_NOMEM_BKPT;
744     if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ) rc = p->rc;
745   }
746 end_of_step:
747   /* There are only a limited number of result codes allowed from the
748   ** statements prepared using the legacy sqlite3_prepare() interface */
749   assert( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0
750        || rc==SQLITE_ROW  || rc==SQLITE_DONE   || rc==SQLITE_ERROR
751        || (rc&0xff)==SQLITE_BUSY || rc==SQLITE_MISUSE
752   );
753   return (rc&db->errMask);
754 }
755 
756 /*
757 ** This is the top-level implementation of sqlite3_step().  Call
758 ** sqlite3Step() to do most of the work.  If a schema error occurs,
759 ** call sqlite3Reprepare() and try again.
760 */
761 int sqlite3_step(sqlite3_stmt *pStmt){
762   int rc = SQLITE_OK;      /* Result from sqlite3Step() */
763   Vdbe *v = (Vdbe*)pStmt;  /* the prepared statement */
764   int cnt = 0;             /* Counter to prevent infinite loop of reprepares */
765   sqlite3 *db;             /* The database connection */
766 
767   if( vdbeSafetyNotNull(v) ){
768     return SQLITE_MISUSE_BKPT;
769   }
770   db = v->db;
771   sqlite3_mutex_enter(db->mutex);
772   v->doingRerun = 0;
773   while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
774          && cnt++ < SQLITE_MAX_SCHEMA_RETRY ){
775     int savedPc = v->pc;
776     rc = sqlite3Reprepare(v);
777     if( rc!=SQLITE_OK ){
778       /* This case occurs after failing to recompile an sql statement.
779       ** The error message from the SQL compiler has already been loaded
780       ** into the database handle. This block copies the error message
781       ** from the database handle into the statement and sets the statement
782       ** program counter to 0 to ensure that when the statement is
783       ** finalized or reset the parser error message is available via
784       ** sqlite3_errmsg() and sqlite3_errcode().
785       */
786       const char *zErr = (const char *)sqlite3_value_text(db->pErr);
787       sqlite3DbFree(db, v->zErrMsg);
788       if( !db->mallocFailed ){
789         v->zErrMsg = sqlite3DbStrDup(db, zErr);
790         v->rc = rc = sqlite3ApiExit(db, rc);
791       } else {
792         v->zErrMsg = 0;
793         v->rc = rc = SQLITE_NOMEM_BKPT;
794       }
795       break;
796     }
797     sqlite3_reset(pStmt);
798     if( savedPc>=0 ) v->doingRerun = 1;
799     assert( v->expired==0 );
800   }
801   sqlite3_mutex_leave(db->mutex);
802   return rc;
803 }
804 
805 
806 /*
807 ** Extract the user data from a sqlite3_context structure and return a
808 ** pointer to it.
809 */
810 void *sqlite3_user_data(sqlite3_context *p){
811   assert( p && p->pFunc );
812   return p->pFunc->pUserData;
813 }
814 
815 /*
816 ** Extract the user data from a sqlite3_context structure and return a
817 ** pointer to it.
818 **
819 ** IMPLEMENTATION-OF: R-46798-50301 The sqlite3_context_db_handle() interface
820 ** returns a copy of the pointer to the database connection (the 1st
821 ** parameter) of the sqlite3_create_function() and
822 ** sqlite3_create_function16() routines that originally registered the
823 ** application defined function.
824 */
825 sqlite3 *sqlite3_context_db_handle(sqlite3_context *p){
826   assert( p && p->pOut );
827   return p->pOut->db;
828 }
829 
830 /*
831 ** If this routine is invoked from within an xColumn method of a virtual
832 ** table, then it returns true if and only if the the call is during an
833 ** UPDATE operation and the value of the column will not be modified
834 ** by the UPDATE.
835 **
836 ** If this routine is called from any context other than within the
837 ** xColumn method of a virtual table, then the return value is meaningless
838 ** and arbitrary.
839 **
840 ** Virtual table implements might use this routine to optimize their
841 ** performance by substituting a NULL result, or some other light-weight
842 ** value, as a signal to the xUpdate routine that the column is unchanged.
843 */
844 int sqlite3_vtab_nochange(sqlite3_context *p){
845   assert( p );
846   return sqlite3_value_nochange(p->pOut);
847 }
848 
849 /*
850 ** Implementation of sqlite3_vtab_in_first() (if bNext==0) and
851 ** sqlite3_vtab_in_next() (if bNext!=0).
852 */
853 static int valueFromValueList(
854   sqlite3_value *pVal,        /* Pointer to the ValueList object */
855   sqlite3_value **ppOut,      /* Store the next value from the list here */
856   int bNext                   /* 1 for _next(). 0 for _first() */
857 ){
858   int rc;
859   ValueList *pRhs;
860 
861   *ppOut = 0;
862   if( pVal==0 ) return SQLITE_MISUSE;
863   pRhs = (ValueList*)sqlite3_value_pointer(pVal, "ValueList");
864   if( pRhs==0 ) return SQLITE_MISUSE;
865   if( bNext ){
866     rc = sqlite3BtreeNext(pRhs->pCsr, 0);
867   }else{
868     int dummy = 0;
869     rc = sqlite3BtreeFirst(pRhs->pCsr, &dummy);
870     assert( rc==SQLITE_OK || sqlite3BtreeEof(pRhs->pCsr) );
871     if( sqlite3BtreeEof(pRhs->pCsr) ) rc = SQLITE_DONE;
872   }
873   if( rc==SQLITE_OK ){
874     u32 sz;       /* Size of current row in bytes */
875     Mem sMem;     /* Raw content of current row */
876     memset(&sMem, 0, sizeof(sMem));
877     sz = sqlite3BtreePayloadSize(pRhs->pCsr);
878     rc = sqlite3VdbeMemFromBtreeZeroOffset(pRhs->pCsr,(int)sz,&sMem);
879     if( rc==SQLITE_OK ){
880       u8 *zBuf = (u8*)sMem.z;
881       u32 iSerial;
882       sqlite3_value *pOut = pRhs->pOut;
883       int iOff = 1 + getVarint32(&zBuf[1], iSerial);
884       sqlite3VdbeSerialGet(&zBuf[iOff], iSerial, pOut);
885       pOut->enc = ENC(pOut->db);
886       if( (pOut->flags & MEM_Ephem)!=0 && sqlite3VdbeMemMakeWriteable(pOut) ){
887         rc = SQLITE_NOMEM;
888       }else{
889         *ppOut = pOut;
890       }
891     }
892     sqlite3VdbeMemRelease(&sMem);
893   }
894   return rc;
895 }
896 
897 /*
898 ** Set the iterator value pVal to point to the first value in the set.
899 ** Set (*ppOut) to point to this value before returning.
900 */
901 int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut){
902   return valueFromValueList(pVal, ppOut, 0);
903 }
904 
905 /*
906 ** Set the iterator value pVal to point to the next value in the set.
907 ** Set (*ppOut) to point to this value before returning.
908 */
909 int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut){
910   return valueFromValueList(pVal, ppOut, 1);
911 }
912 
913 /*
914 ** Return the current time for a statement.  If the current time
915 ** is requested more than once within the same run of a single prepared
916 ** statement, the exact same time is returned for each invocation regardless
917 ** of the amount of time that elapses between invocations.  In other words,
918 ** the time returned is always the time of the first call.
919 */
920 sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context *p){
921   int rc;
922 #ifndef SQLITE_ENABLE_STAT4
923   sqlite3_int64 *piTime = &p->pVdbe->iCurrentTime;
924   assert( p->pVdbe!=0 );
925 #else
926   sqlite3_int64 iTime = 0;
927   sqlite3_int64 *piTime = p->pVdbe!=0 ? &p->pVdbe->iCurrentTime : &iTime;
928 #endif
929   if( *piTime==0 ){
930     rc = sqlite3OsCurrentTimeInt64(p->pOut->db->pVfs, piTime);
931     if( rc ) *piTime = 0;
932   }
933   return *piTime;
934 }
935 
936 /*
937 ** Create a new aggregate context for p and return a pointer to
938 ** its pMem->z element.
939 */
940 static SQLITE_NOINLINE void *createAggContext(sqlite3_context *p, int nByte){
941   Mem *pMem = p->pMem;
942   assert( (pMem->flags & MEM_Agg)==0 );
943   if( nByte<=0 ){
944     sqlite3VdbeMemSetNull(pMem);
945     pMem->z = 0;
946   }else{
947     sqlite3VdbeMemClearAndResize(pMem, nByte);
948     pMem->flags = MEM_Agg;
949     pMem->u.pDef = p->pFunc;
950     if( pMem->z ){
951       memset(pMem->z, 0, nByte);
952     }
953   }
954   return (void*)pMem->z;
955 }
956 
957 /*
958 ** Allocate or return the aggregate context for a user function.  A new
959 ** context is allocated on the first call.  Subsequent calls return the
960 ** same context that was returned on prior calls.
961 */
962 void *sqlite3_aggregate_context(sqlite3_context *p, int nByte){
963   assert( p && p->pFunc && p->pFunc->xFinalize );
964   assert( sqlite3_mutex_held(p->pOut->db->mutex) );
965   testcase( nByte<0 );
966   if( (p->pMem->flags & MEM_Agg)==0 ){
967     return createAggContext(p, nByte);
968   }else{
969     return (void*)p->pMem->z;
970   }
971 }
972 
973 /*
974 ** Return the auxiliary data pointer, if any, for the iArg'th argument to
975 ** the user-function defined by pCtx.
976 **
977 ** The left-most argument is 0.
978 **
979 ** Undocumented behavior:  If iArg is negative then access a cache of
980 ** auxiliary data pointers that is available to all functions within a
981 ** single prepared statement.  The iArg values must match.
982 */
983 void *sqlite3_get_auxdata(sqlite3_context *pCtx, int iArg){
984   AuxData *pAuxData;
985 
986   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
987 #if SQLITE_ENABLE_STAT4
988   if( pCtx->pVdbe==0 ) return 0;
989 #else
990   assert( pCtx->pVdbe!=0 );
991 #endif
992   for(pAuxData=pCtx->pVdbe->pAuxData; pAuxData; pAuxData=pAuxData->pNextAux){
993     if(  pAuxData->iAuxArg==iArg && (pAuxData->iAuxOp==pCtx->iOp || iArg<0) ){
994       return pAuxData->pAux;
995     }
996   }
997   return 0;
998 }
999 
1000 /*
1001 ** Set the auxiliary data pointer and delete function, for the iArg'th
1002 ** argument to the user-function defined by pCtx. Any previous value is
1003 ** deleted by calling the delete function specified when it was set.
1004 **
1005 ** The left-most argument is 0.
1006 **
1007 ** Undocumented behavior:  If iArg is negative then make the data available
1008 ** to all functions within the current prepared statement using iArg as an
1009 ** access code.
1010 */
1011 void sqlite3_set_auxdata(
1012   sqlite3_context *pCtx,
1013   int iArg,
1014   void *pAux,
1015   void (*xDelete)(void*)
1016 ){
1017   AuxData *pAuxData;
1018   Vdbe *pVdbe = pCtx->pVdbe;
1019 
1020   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
1021 #ifdef SQLITE_ENABLE_STAT4
1022   if( pVdbe==0 ) goto failed;
1023 #else
1024   assert( pVdbe!=0 );
1025 #endif
1026 
1027   for(pAuxData=pVdbe->pAuxData; pAuxData; pAuxData=pAuxData->pNextAux){
1028     if( pAuxData->iAuxArg==iArg && (pAuxData->iAuxOp==pCtx->iOp || iArg<0) ){
1029       break;
1030     }
1031   }
1032   if( pAuxData==0 ){
1033     pAuxData = sqlite3DbMallocZero(pVdbe->db, sizeof(AuxData));
1034     if( !pAuxData ) goto failed;
1035     pAuxData->iAuxOp = pCtx->iOp;
1036     pAuxData->iAuxArg = iArg;
1037     pAuxData->pNextAux = pVdbe->pAuxData;
1038     pVdbe->pAuxData = pAuxData;
1039     if( pCtx->isError==0 ) pCtx->isError = -1;
1040   }else if( pAuxData->xDeleteAux ){
1041     pAuxData->xDeleteAux(pAuxData->pAux);
1042   }
1043 
1044   pAuxData->pAux = pAux;
1045   pAuxData->xDeleteAux = xDelete;
1046   return;
1047 
1048 failed:
1049   if( xDelete ){
1050     xDelete(pAux);
1051   }
1052 }
1053 
1054 #ifndef SQLITE_OMIT_DEPRECATED
1055 /*
1056 ** Return the number of times the Step function of an aggregate has been
1057 ** called.
1058 **
1059 ** This function is deprecated.  Do not use it for new code.  It is
1060 ** provide only to avoid breaking legacy code.  New aggregate function
1061 ** implementations should keep their own counts within their aggregate
1062 ** context.
1063 */
1064 int sqlite3_aggregate_count(sqlite3_context *p){
1065   assert( p && p->pMem && p->pFunc && p->pFunc->xFinalize );
1066   return p->pMem->n;
1067 }
1068 #endif
1069 
1070 /*
1071 ** Return the number of columns in the result set for the statement pStmt.
1072 */
1073 int sqlite3_column_count(sqlite3_stmt *pStmt){
1074   Vdbe *pVm = (Vdbe *)pStmt;
1075   return pVm ? pVm->nResColumn : 0;
1076 }
1077 
1078 /*
1079 ** Return the number of values available from the current row of the
1080 ** currently executing statement pStmt.
1081 */
1082 int sqlite3_data_count(sqlite3_stmt *pStmt){
1083   Vdbe *pVm = (Vdbe *)pStmt;
1084   if( pVm==0 || pVm->pResultSet==0 ) return 0;
1085   return pVm->nResColumn;
1086 }
1087 
1088 /*
1089 ** Return a pointer to static memory containing an SQL NULL value.
1090 **
1091 ** Must be revised if column order for Mem changes.  tag-20220228a.
1092 */
1093 static const Mem *columnNullValue(void){
1094   /* Even though the Mem structure contains an element
1095   ** of type i64, on certain architectures (x86) with certain compiler
1096   ** switches (-Os), gcc may align this Mem object on a 4-byte boundary
1097   ** instead of an 8-byte one. This all works fine, except that when
1098   ** running with SQLITE_DEBUG defined the SQLite code sometimes assert()s
1099   ** that a Mem structure is located on an 8-byte boundary. To prevent
1100   ** these assert()s from failing, when building with SQLITE_DEBUG defined
1101   ** using gcc, we force nullMem to be 8-byte aligned using the magical
1102   ** __attribute__((aligned(8))) macro.  */
1103   static const Mem nullMem
1104 #if defined(SQLITE_DEBUG) && defined(__GNUC__)
1105     __attribute__((aligned(8)))
1106 #endif
1107     = {
1108         /* .u          = */ {0},
1109         /* .z          = */ (char*)0,
1110         /* .n          = */ (int)0,
1111         /* .flags      = */ (u16)MEM_Null,
1112         /* .enc        = */ (u8)0,
1113         /* .eSubtype   = */ (u8)0,
1114         /* .db         = */ (sqlite3*)0,
1115         /* .szMalloc   = */ (int)0,
1116         /* .uTemp      = */ (u32)0,
1117         /* .zMalloc    = */ (char*)0,
1118         /* .xDel       = */ (void(*)(void*))0,
1119 #ifdef SQLITE_DEBUG
1120         /* .pScopyFrom = */ (Mem*)0,
1121         /* .mScopyFlags= */ 0,
1122 #endif
1123       };
1124   return &nullMem;
1125 }
1126 
1127 /*
1128 ** Check to see if column iCol of the given statement is valid.  If
1129 ** it is, return a pointer to the Mem for the value of that column.
1130 ** If iCol is not valid, return a pointer to a Mem which has a value
1131 ** of NULL.
1132 */
1133 static Mem *columnMem(sqlite3_stmt *pStmt, int i){
1134   Vdbe *pVm;
1135   Mem *pOut;
1136 
1137   pVm = (Vdbe *)pStmt;
1138   if( pVm==0 ) return (Mem*)columnNullValue();
1139   assert( pVm->db );
1140   sqlite3_mutex_enter(pVm->db->mutex);
1141   if( pVm->pResultSet!=0 && i<pVm->nResColumn && i>=0 ){
1142     pOut = &pVm->pResultSet[i];
1143   }else{
1144     sqlite3Error(pVm->db, SQLITE_RANGE);
1145     pOut = (Mem*)columnNullValue();
1146   }
1147   return pOut;
1148 }
1149 
1150 /*
1151 ** This function is called after invoking an sqlite3_value_XXX function on a
1152 ** column value (i.e. a value returned by evaluating an SQL expression in the
1153 ** select list of a SELECT statement) that may cause a malloc() failure. If
1154 ** malloc() has failed, the threads mallocFailed flag is cleared and the result
1155 ** code of statement pStmt set to SQLITE_NOMEM.
1156 **
1157 ** Specifically, this is called from within:
1158 **
1159 **     sqlite3_column_int()
1160 **     sqlite3_column_int64()
1161 **     sqlite3_column_text()
1162 **     sqlite3_column_text16()
1163 **     sqlite3_column_real()
1164 **     sqlite3_column_bytes()
1165 **     sqlite3_column_bytes16()
1166 **     sqiite3_column_blob()
1167 */
1168 static void columnMallocFailure(sqlite3_stmt *pStmt)
1169 {
1170   /* If malloc() failed during an encoding conversion within an
1171   ** sqlite3_column_XXX API, then set the return code of the statement to
1172   ** SQLITE_NOMEM. The next call to _step() (if any) will return SQLITE_ERROR
1173   ** and _finalize() will return NOMEM.
1174   */
1175   Vdbe *p = (Vdbe *)pStmt;
1176   if( p ){
1177     assert( p->db!=0 );
1178     assert( sqlite3_mutex_held(p->db->mutex) );
1179     p->rc = sqlite3ApiExit(p->db, p->rc);
1180     sqlite3_mutex_leave(p->db->mutex);
1181   }
1182 }
1183 
1184 /**************************** sqlite3_column_  *******************************
1185 ** The following routines are used to access elements of the current row
1186 ** in the result set.
1187 */
1188 const void *sqlite3_column_blob(sqlite3_stmt *pStmt, int i){
1189   const void *val;
1190   val = sqlite3_value_blob( columnMem(pStmt,i) );
1191   /* Even though there is no encoding conversion, value_blob() might
1192   ** need to call malloc() to expand the result of a zeroblob()
1193   ** expression.
1194   */
1195   columnMallocFailure(pStmt);
1196   return val;
1197 }
1198 int sqlite3_column_bytes(sqlite3_stmt *pStmt, int i){
1199   int val = sqlite3_value_bytes( columnMem(pStmt,i) );
1200   columnMallocFailure(pStmt);
1201   return val;
1202 }
1203 int sqlite3_column_bytes16(sqlite3_stmt *pStmt, int i){
1204   int val = sqlite3_value_bytes16( columnMem(pStmt,i) );
1205   columnMallocFailure(pStmt);
1206   return val;
1207 }
1208 double sqlite3_column_double(sqlite3_stmt *pStmt, int i){
1209   double val = sqlite3_value_double( columnMem(pStmt,i) );
1210   columnMallocFailure(pStmt);
1211   return val;
1212 }
1213 int sqlite3_column_int(sqlite3_stmt *pStmt, int i){
1214   int val = sqlite3_value_int( columnMem(pStmt,i) );
1215   columnMallocFailure(pStmt);
1216   return val;
1217 }
1218 sqlite_int64 sqlite3_column_int64(sqlite3_stmt *pStmt, int i){
1219   sqlite_int64 val = sqlite3_value_int64( columnMem(pStmt,i) );
1220   columnMallocFailure(pStmt);
1221   return val;
1222 }
1223 const unsigned char *sqlite3_column_text(sqlite3_stmt *pStmt, int i){
1224   const unsigned char *val = sqlite3_value_text( columnMem(pStmt,i) );
1225   columnMallocFailure(pStmt);
1226   return val;
1227 }
1228 sqlite3_value *sqlite3_column_value(sqlite3_stmt *pStmt, int i){
1229   Mem *pOut = columnMem(pStmt, i);
1230   if( pOut->flags&MEM_Static ){
1231     pOut->flags &= ~MEM_Static;
1232     pOut->flags |= MEM_Ephem;
1233   }
1234   columnMallocFailure(pStmt);
1235   return (sqlite3_value *)pOut;
1236 }
1237 #ifndef SQLITE_OMIT_UTF16
1238 const void *sqlite3_column_text16(sqlite3_stmt *pStmt, int i){
1239   const void *val = sqlite3_value_text16( columnMem(pStmt,i) );
1240   columnMallocFailure(pStmt);
1241   return val;
1242 }
1243 #endif /* SQLITE_OMIT_UTF16 */
1244 int sqlite3_column_type(sqlite3_stmt *pStmt, int i){
1245   int iType = sqlite3_value_type( columnMem(pStmt,i) );
1246   columnMallocFailure(pStmt);
1247   return iType;
1248 }
1249 
1250 /*
1251 ** Convert the N-th element of pStmt->pColName[] into a string using
1252 ** xFunc() then return that string.  If N is out of range, return 0.
1253 **
1254 ** There are up to 5 names for each column.  useType determines which
1255 ** name is returned.  Here are the names:
1256 **
1257 **    0      The column name as it should be displayed for output
1258 **    1      The datatype name for the column
1259 **    2      The name of the database that the column derives from
1260 **    3      The name of the table that the column derives from
1261 **    4      The name of the table column that the result column derives from
1262 **
1263 ** If the result is not a simple column reference (if it is an expression
1264 ** or a constant) then useTypes 2, 3, and 4 return NULL.
1265 */
1266 static const void *columnName(
1267   sqlite3_stmt *pStmt,     /* The statement */
1268   int N,                   /* Which column to get the name for */
1269   int useUtf16,            /* True to return the name as UTF16 */
1270   int useType              /* What type of name */
1271 ){
1272   const void *ret;
1273   Vdbe *p;
1274   int n;
1275   sqlite3 *db;
1276 #ifdef SQLITE_ENABLE_API_ARMOR
1277   if( pStmt==0 ){
1278     (void)SQLITE_MISUSE_BKPT;
1279     return 0;
1280   }
1281 #endif
1282   ret = 0;
1283   p = (Vdbe *)pStmt;
1284   db = p->db;
1285   assert( db!=0 );
1286   n = sqlite3_column_count(pStmt);
1287   if( N<n && N>=0 ){
1288     N += useType*n;
1289     sqlite3_mutex_enter(db->mutex);
1290     assert( db->mallocFailed==0 );
1291 #ifndef SQLITE_OMIT_UTF16
1292     if( useUtf16 ){
1293       ret = sqlite3_value_text16((sqlite3_value*)&p->aColName[N]);
1294     }else
1295 #endif
1296     {
1297       ret = sqlite3_value_text((sqlite3_value*)&p->aColName[N]);
1298     }
1299     /* A malloc may have failed inside of the _text() call. If this
1300     ** is the case, clear the mallocFailed flag and return NULL.
1301     */
1302     if( db->mallocFailed ){
1303       sqlite3OomClear(db);
1304       ret = 0;
1305     }
1306     sqlite3_mutex_leave(db->mutex);
1307   }
1308   return ret;
1309 }
1310 
1311 /*
1312 ** Return the name of the Nth column of the result set returned by SQL
1313 ** statement pStmt.
1314 */
1315 const char *sqlite3_column_name(sqlite3_stmt *pStmt, int N){
1316   return columnName(pStmt, N, 0, COLNAME_NAME);
1317 }
1318 #ifndef SQLITE_OMIT_UTF16
1319 const void *sqlite3_column_name16(sqlite3_stmt *pStmt, int N){
1320   return columnName(pStmt, N, 1, COLNAME_NAME);
1321 }
1322 #endif
1323 
1324 /*
1325 ** Constraint:  If you have ENABLE_COLUMN_METADATA then you must
1326 ** not define OMIT_DECLTYPE.
1327 */
1328 #if defined(SQLITE_OMIT_DECLTYPE) && defined(SQLITE_ENABLE_COLUMN_METADATA)
1329 # error "Must not define both SQLITE_OMIT_DECLTYPE \
1330          and SQLITE_ENABLE_COLUMN_METADATA"
1331 #endif
1332 
1333 #ifndef SQLITE_OMIT_DECLTYPE
1334 /*
1335 ** Return the column declaration type (if applicable) of the 'i'th column
1336 ** of the result set of SQL statement pStmt.
1337 */
1338 const char *sqlite3_column_decltype(sqlite3_stmt *pStmt, int N){
1339   return columnName(pStmt, N, 0, COLNAME_DECLTYPE);
1340 }
1341 #ifndef SQLITE_OMIT_UTF16
1342 const void *sqlite3_column_decltype16(sqlite3_stmt *pStmt, int N){
1343   return columnName(pStmt, N, 1, COLNAME_DECLTYPE);
1344 }
1345 #endif /* SQLITE_OMIT_UTF16 */
1346 #endif /* SQLITE_OMIT_DECLTYPE */
1347 
1348 #ifdef SQLITE_ENABLE_COLUMN_METADATA
1349 /*
1350 ** Return the name of the database from which a result column derives.
1351 ** NULL is returned if the result column is an expression or constant or
1352 ** anything else which is not an unambiguous reference to a database column.
1353 */
1354 const char *sqlite3_column_database_name(sqlite3_stmt *pStmt, int N){
1355   return columnName(pStmt, N, 0, COLNAME_DATABASE);
1356 }
1357 #ifndef SQLITE_OMIT_UTF16
1358 const void *sqlite3_column_database_name16(sqlite3_stmt *pStmt, int N){
1359   return columnName(pStmt, N, 1, COLNAME_DATABASE);
1360 }
1361 #endif /* SQLITE_OMIT_UTF16 */
1362 
1363 /*
1364 ** Return the name of the table from which a result column derives.
1365 ** NULL is returned if the result column is an expression or constant or
1366 ** anything else which is not an unambiguous reference to a database column.
1367 */
1368 const char *sqlite3_column_table_name(sqlite3_stmt *pStmt, int N){
1369   return columnName(pStmt, N, 0, COLNAME_TABLE);
1370 }
1371 #ifndef SQLITE_OMIT_UTF16
1372 const void *sqlite3_column_table_name16(sqlite3_stmt *pStmt, int N){
1373   return columnName(pStmt, N, 1, COLNAME_TABLE);
1374 }
1375 #endif /* SQLITE_OMIT_UTF16 */
1376 
1377 /*
1378 ** Return the name of the table column from which a result column derives.
1379 ** NULL is returned if the result column is an expression or constant or
1380 ** anything else which is not an unambiguous reference to a database column.
1381 */
1382 const char *sqlite3_column_origin_name(sqlite3_stmt *pStmt, int N){
1383   return columnName(pStmt, N, 0, COLNAME_COLUMN);
1384 }
1385 #ifndef SQLITE_OMIT_UTF16
1386 const void *sqlite3_column_origin_name16(sqlite3_stmt *pStmt, int N){
1387   return columnName(pStmt, N, 1, COLNAME_COLUMN);
1388 }
1389 #endif /* SQLITE_OMIT_UTF16 */
1390 #endif /* SQLITE_ENABLE_COLUMN_METADATA */
1391 
1392 
1393 /******************************* sqlite3_bind_  ***************************
1394 **
1395 ** Routines used to attach values to wildcards in a compiled SQL statement.
1396 */
1397 /*
1398 ** Unbind the value bound to variable i in virtual machine p. This is the
1399 ** the same as binding a NULL value to the column. If the "i" parameter is
1400 ** out of range, then SQLITE_RANGE is returned. Othewise SQLITE_OK.
1401 **
1402 ** A successful evaluation of this routine acquires the mutex on p.
1403 ** the mutex is released if any kind of error occurs.
1404 **
1405 ** The error code stored in database p->db is overwritten with the return
1406 ** value in any case.
1407 */
1408 static int vdbeUnbind(Vdbe *p, int i){
1409   Mem *pVar;
1410   if( vdbeSafetyNotNull(p) ){
1411     return SQLITE_MISUSE_BKPT;
1412   }
1413   sqlite3_mutex_enter(p->db->mutex);
1414   if( p->iVdbeMagic!=VDBE_MAGIC_RUN || p->pc>=0 ){
1415     sqlite3Error(p->db, SQLITE_MISUSE);
1416     sqlite3_mutex_leave(p->db->mutex);
1417     sqlite3_log(SQLITE_MISUSE,
1418         "bind on a busy prepared statement: [%s]", p->zSql);
1419     return SQLITE_MISUSE_BKPT;
1420   }
1421   if( i<1 || i>p->nVar ){
1422     sqlite3Error(p->db, SQLITE_RANGE);
1423     sqlite3_mutex_leave(p->db->mutex);
1424     return SQLITE_RANGE;
1425   }
1426   i--;
1427   pVar = &p->aVar[i];
1428   sqlite3VdbeMemRelease(pVar);
1429   pVar->flags = MEM_Null;
1430   p->db->errCode = SQLITE_OK;
1431 
1432   /* If the bit corresponding to this variable in Vdbe.expmask is set, then
1433   ** binding a new value to this variable invalidates the current query plan.
1434   **
1435   ** IMPLEMENTATION-OF: R-57496-20354 If the specific value bound to a host
1436   ** parameter in the WHERE clause might influence the choice of query plan
1437   ** for a statement, then the statement will be automatically recompiled,
1438   ** as if there had been a schema change, on the first sqlite3_step() call
1439   ** following any change to the bindings of that parameter.
1440   */
1441   assert( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || p->expmask==0 );
1442   if( p->expmask!=0 && (p->expmask & (i>=31 ? 0x80000000 : (u32)1<<i))!=0 ){
1443     p->expired = 1;
1444   }
1445   return SQLITE_OK;
1446 }
1447 
1448 /*
1449 ** Bind a text or BLOB value.
1450 */
1451 static int bindText(
1452   sqlite3_stmt *pStmt,   /* The statement to bind against */
1453   int i,                 /* Index of the parameter to bind */
1454   const void *zData,     /* Pointer to the data to be bound */
1455   i64 nData,             /* Number of bytes of data to be bound */
1456   void (*xDel)(void*),   /* Destructor for the data */
1457   u8 encoding            /* Encoding for the data */
1458 ){
1459   Vdbe *p = (Vdbe *)pStmt;
1460   Mem *pVar;
1461   int rc;
1462 
1463   rc = vdbeUnbind(p, i);
1464   if( rc==SQLITE_OK ){
1465     if( zData!=0 ){
1466       pVar = &p->aVar[i-1];
1467       rc = sqlite3VdbeMemSetStr(pVar, zData, nData, encoding, xDel);
1468       if( rc==SQLITE_OK && encoding!=0 ){
1469         rc = sqlite3VdbeChangeEncoding(pVar, ENC(p->db));
1470       }
1471       if( rc ){
1472         sqlite3Error(p->db, rc);
1473         rc = sqlite3ApiExit(p->db, rc);
1474       }
1475     }
1476     sqlite3_mutex_leave(p->db->mutex);
1477   }else if( xDel!=SQLITE_STATIC && xDel!=SQLITE_TRANSIENT ){
1478     xDel((void*)zData);
1479   }
1480   return rc;
1481 }
1482 
1483 
1484 /*
1485 ** Bind a blob value to an SQL statement variable.
1486 */
1487 int sqlite3_bind_blob(
1488   sqlite3_stmt *pStmt,
1489   int i,
1490   const void *zData,
1491   int nData,
1492   void (*xDel)(void*)
1493 ){
1494 #ifdef SQLITE_ENABLE_API_ARMOR
1495   if( nData<0 ) return SQLITE_MISUSE_BKPT;
1496 #endif
1497   return bindText(pStmt, i, zData, nData, xDel, 0);
1498 }
1499 int sqlite3_bind_blob64(
1500   sqlite3_stmt *pStmt,
1501   int i,
1502   const void *zData,
1503   sqlite3_uint64 nData,
1504   void (*xDel)(void*)
1505 ){
1506   assert( xDel!=SQLITE_DYNAMIC );
1507   return bindText(pStmt, i, zData, nData, xDel, 0);
1508 }
1509 int sqlite3_bind_double(sqlite3_stmt *pStmt, int i, double rValue){
1510   int rc;
1511   Vdbe *p = (Vdbe *)pStmt;
1512   rc = vdbeUnbind(p, i);
1513   if( rc==SQLITE_OK ){
1514     sqlite3VdbeMemSetDouble(&p->aVar[i-1], rValue);
1515     sqlite3_mutex_leave(p->db->mutex);
1516   }
1517   return rc;
1518 }
1519 int sqlite3_bind_int(sqlite3_stmt *p, int i, int iValue){
1520   return sqlite3_bind_int64(p, i, (i64)iValue);
1521 }
1522 int sqlite3_bind_int64(sqlite3_stmt *pStmt, int i, sqlite_int64 iValue){
1523   int rc;
1524   Vdbe *p = (Vdbe *)pStmt;
1525   rc = vdbeUnbind(p, i);
1526   if( rc==SQLITE_OK ){
1527     sqlite3VdbeMemSetInt64(&p->aVar[i-1], iValue);
1528     sqlite3_mutex_leave(p->db->mutex);
1529   }
1530   return rc;
1531 }
1532 int sqlite3_bind_null(sqlite3_stmt *pStmt, int i){
1533   int rc;
1534   Vdbe *p = (Vdbe*)pStmt;
1535   rc = vdbeUnbind(p, i);
1536   if( rc==SQLITE_OK ){
1537     sqlite3_mutex_leave(p->db->mutex);
1538   }
1539   return rc;
1540 }
1541 int sqlite3_bind_pointer(
1542   sqlite3_stmt *pStmt,
1543   int i,
1544   void *pPtr,
1545   const char *zPTtype,
1546   void (*xDestructor)(void*)
1547 ){
1548   int rc;
1549   Vdbe *p = (Vdbe*)pStmt;
1550   rc = vdbeUnbind(p, i);
1551   if( rc==SQLITE_OK ){
1552     sqlite3VdbeMemSetPointer(&p->aVar[i-1], pPtr, zPTtype, xDestructor);
1553     sqlite3_mutex_leave(p->db->mutex);
1554   }else if( xDestructor ){
1555     xDestructor(pPtr);
1556   }
1557   return rc;
1558 }
1559 int sqlite3_bind_text(
1560   sqlite3_stmt *pStmt,
1561   int i,
1562   const char *zData,
1563   int nData,
1564   void (*xDel)(void*)
1565 ){
1566   return bindText(pStmt, i, zData, nData, xDel, SQLITE_UTF8);
1567 }
1568 int sqlite3_bind_text64(
1569   sqlite3_stmt *pStmt,
1570   int i,
1571   const char *zData,
1572   sqlite3_uint64 nData,
1573   void (*xDel)(void*),
1574   unsigned char enc
1575 ){
1576   assert( xDel!=SQLITE_DYNAMIC );
1577   if( enc==SQLITE_UTF16 ) enc = SQLITE_UTF16NATIVE;
1578   return bindText(pStmt, i, zData, nData, xDel, enc);
1579 }
1580 #ifndef SQLITE_OMIT_UTF16
1581 int sqlite3_bind_text16(
1582   sqlite3_stmt *pStmt,
1583   int i,
1584   const void *zData,
1585   int nData,
1586   void (*xDel)(void*)
1587 ){
1588   return bindText(pStmt, i, zData, nData, xDel, SQLITE_UTF16NATIVE);
1589 }
1590 #endif /* SQLITE_OMIT_UTF16 */
1591 int sqlite3_bind_value(sqlite3_stmt *pStmt, int i, const sqlite3_value *pValue){
1592   int rc;
1593   switch( sqlite3_value_type((sqlite3_value*)pValue) ){
1594     case SQLITE_INTEGER: {
1595       rc = sqlite3_bind_int64(pStmt, i, pValue->u.i);
1596       break;
1597     }
1598     case SQLITE_FLOAT: {
1599       assert( pValue->flags & (MEM_Real|MEM_IntReal) );
1600       rc = sqlite3_bind_double(pStmt, i,
1601           (pValue->flags & MEM_Real) ? pValue->u.r : (double)pValue->u.i
1602       );
1603       break;
1604     }
1605     case SQLITE_BLOB: {
1606       if( pValue->flags & MEM_Zero ){
1607         rc = sqlite3_bind_zeroblob(pStmt, i, pValue->u.nZero);
1608       }else{
1609         rc = sqlite3_bind_blob(pStmt, i, pValue->z, pValue->n,SQLITE_TRANSIENT);
1610       }
1611       break;
1612     }
1613     case SQLITE_TEXT: {
1614       rc = bindText(pStmt,i,  pValue->z, pValue->n, SQLITE_TRANSIENT,
1615                               pValue->enc);
1616       break;
1617     }
1618     default: {
1619       rc = sqlite3_bind_null(pStmt, i);
1620       break;
1621     }
1622   }
1623   return rc;
1624 }
1625 int sqlite3_bind_zeroblob(sqlite3_stmt *pStmt, int i, int n){
1626   int rc;
1627   Vdbe *p = (Vdbe *)pStmt;
1628   rc = vdbeUnbind(p, i);
1629   if( rc==SQLITE_OK ){
1630 #ifndef SQLITE_OMIT_INCRBLOB
1631     sqlite3VdbeMemSetZeroBlob(&p->aVar[i-1], n);
1632 #else
1633     rc = sqlite3VdbeMemSetZeroBlob(&p->aVar[i-1], n);
1634 #endif
1635     sqlite3_mutex_leave(p->db->mutex);
1636   }
1637   return rc;
1638 }
1639 int sqlite3_bind_zeroblob64(sqlite3_stmt *pStmt, int i, sqlite3_uint64 n){
1640   int rc;
1641   Vdbe *p = (Vdbe *)pStmt;
1642   sqlite3_mutex_enter(p->db->mutex);
1643   if( n>(u64)p->db->aLimit[SQLITE_LIMIT_LENGTH] ){
1644     rc = SQLITE_TOOBIG;
1645   }else{
1646     assert( (n & 0x7FFFFFFF)==n );
1647     rc = sqlite3_bind_zeroblob(pStmt, i, n);
1648   }
1649   rc = sqlite3ApiExit(p->db, rc);
1650   sqlite3_mutex_leave(p->db->mutex);
1651   return rc;
1652 }
1653 
1654 /*
1655 ** Return the number of wildcards that can be potentially bound to.
1656 ** This routine is added to support DBD::SQLite.
1657 */
1658 int sqlite3_bind_parameter_count(sqlite3_stmt *pStmt){
1659   Vdbe *p = (Vdbe*)pStmt;
1660   return p ? p->nVar : 0;
1661 }
1662 
1663 /*
1664 ** Return the name of a wildcard parameter.  Return NULL if the index
1665 ** is out of range or if the wildcard is unnamed.
1666 **
1667 ** The result is always UTF-8.
1668 */
1669 const char *sqlite3_bind_parameter_name(sqlite3_stmt *pStmt, int i){
1670   Vdbe *p = (Vdbe*)pStmt;
1671   if( p==0 ) return 0;
1672   return sqlite3VListNumToName(p->pVList, i);
1673 }
1674 
1675 /*
1676 ** Given a wildcard parameter name, return the index of the variable
1677 ** with that name.  If there is no variable with the given name,
1678 ** return 0.
1679 */
1680 int sqlite3VdbeParameterIndex(Vdbe *p, const char *zName, int nName){
1681   if( p==0 || zName==0 ) return 0;
1682   return sqlite3VListNameToNum(p->pVList, zName, nName);
1683 }
1684 int sqlite3_bind_parameter_index(sqlite3_stmt *pStmt, const char *zName){
1685   return sqlite3VdbeParameterIndex((Vdbe*)pStmt, zName, sqlite3Strlen30(zName));
1686 }
1687 
1688 /*
1689 ** Transfer all bindings from the first statement over to the second.
1690 */
1691 int sqlite3TransferBindings(sqlite3_stmt *pFromStmt, sqlite3_stmt *pToStmt){
1692   Vdbe *pFrom = (Vdbe*)pFromStmt;
1693   Vdbe *pTo = (Vdbe*)pToStmt;
1694   int i;
1695   assert( pTo->db==pFrom->db );
1696   assert( pTo->nVar==pFrom->nVar );
1697   sqlite3_mutex_enter(pTo->db->mutex);
1698   for(i=0; i<pFrom->nVar; i++){
1699     sqlite3VdbeMemMove(&pTo->aVar[i], &pFrom->aVar[i]);
1700   }
1701   sqlite3_mutex_leave(pTo->db->mutex);
1702   return SQLITE_OK;
1703 }
1704 
1705 #ifndef SQLITE_OMIT_DEPRECATED
1706 /*
1707 ** Deprecated external interface.  Internal/core SQLite code
1708 ** should call sqlite3TransferBindings.
1709 **
1710 ** It is misuse to call this routine with statements from different
1711 ** database connections.  But as this is a deprecated interface, we
1712 ** will not bother to check for that condition.
1713 **
1714 ** If the two statements contain a different number of bindings, then
1715 ** an SQLITE_ERROR is returned.  Nothing else can go wrong, so otherwise
1716 ** SQLITE_OK is returned.
1717 */
1718 int sqlite3_transfer_bindings(sqlite3_stmt *pFromStmt, sqlite3_stmt *pToStmt){
1719   Vdbe *pFrom = (Vdbe*)pFromStmt;
1720   Vdbe *pTo = (Vdbe*)pToStmt;
1721   if( pFrom->nVar!=pTo->nVar ){
1722     return SQLITE_ERROR;
1723   }
1724   assert( (pTo->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || pTo->expmask==0 );
1725   if( pTo->expmask ){
1726     pTo->expired = 1;
1727   }
1728   assert( (pFrom->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || pFrom->expmask==0 );
1729   if( pFrom->expmask ){
1730     pFrom->expired = 1;
1731   }
1732   return sqlite3TransferBindings(pFromStmt, pToStmt);
1733 }
1734 #endif
1735 
1736 /*
1737 ** Return the sqlite3* database handle to which the prepared statement given
1738 ** in the argument belongs.  This is the same database handle that was
1739 ** the first argument to the sqlite3_prepare() that was used to create
1740 ** the statement in the first place.
1741 */
1742 sqlite3 *sqlite3_db_handle(sqlite3_stmt *pStmt){
1743   return pStmt ? ((Vdbe*)pStmt)->db : 0;
1744 }
1745 
1746 /*
1747 ** Return true if the prepared statement is guaranteed to not modify the
1748 ** database.
1749 */
1750 int sqlite3_stmt_readonly(sqlite3_stmt *pStmt){
1751   return pStmt ? ((Vdbe*)pStmt)->readOnly : 1;
1752 }
1753 
1754 /*
1755 ** Return 1 if the statement is an EXPLAIN and return 2 if the
1756 ** statement is an EXPLAIN QUERY PLAN
1757 */
1758 int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt){
1759   return pStmt ? ((Vdbe*)pStmt)->explain : 0;
1760 }
1761 
1762 /*
1763 ** Return true if the prepared statement is in need of being reset.
1764 */
1765 int sqlite3_stmt_busy(sqlite3_stmt *pStmt){
1766   Vdbe *v = (Vdbe*)pStmt;
1767   return v!=0 && v->iVdbeMagic==VDBE_MAGIC_RUN && v->pc>=0;
1768 }
1769 
1770 /*
1771 ** Return a pointer to the next prepared statement after pStmt associated
1772 ** with database connection pDb.  If pStmt is NULL, return the first
1773 ** prepared statement for the database connection.  Return NULL if there
1774 ** are no more.
1775 */
1776 sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt){
1777   sqlite3_stmt *pNext;
1778 #ifdef SQLITE_ENABLE_API_ARMOR
1779   if( !sqlite3SafetyCheckOk(pDb) ){
1780     (void)SQLITE_MISUSE_BKPT;
1781     return 0;
1782   }
1783 #endif
1784   sqlite3_mutex_enter(pDb->mutex);
1785   if( pStmt==0 ){
1786     pNext = (sqlite3_stmt*)pDb->pVdbe;
1787   }else{
1788     pNext = (sqlite3_stmt*)((Vdbe*)pStmt)->pNext;
1789   }
1790   sqlite3_mutex_leave(pDb->mutex);
1791   return pNext;
1792 }
1793 
1794 /*
1795 ** Return the value of a status counter for a prepared statement
1796 */
1797 int sqlite3_stmt_status(sqlite3_stmt *pStmt, int op, int resetFlag){
1798   Vdbe *pVdbe = (Vdbe*)pStmt;
1799   u32 v;
1800 #ifdef SQLITE_ENABLE_API_ARMOR
1801   if( !pStmt
1802    || (op!=SQLITE_STMTSTATUS_MEMUSED && (op<0||op>=ArraySize(pVdbe->aCounter)))
1803   ){
1804     (void)SQLITE_MISUSE_BKPT;
1805     return 0;
1806   }
1807 #endif
1808   if( op==SQLITE_STMTSTATUS_MEMUSED ){
1809     sqlite3 *db = pVdbe->db;
1810     sqlite3_mutex_enter(db->mutex);
1811     v = 0;
1812     db->pnBytesFreed = (int*)&v;
1813     sqlite3VdbeClearObject(db, pVdbe);
1814     sqlite3DbFree(db, pVdbe);
1815     db->pnBytesFreed = 0;
1816     sqlite3_mutex_leave(db->mutex);
1817   }else{
1818     v = pVdbe->aCounter[op];
1819     if( resetFlag ) pVdbe->aCounter[op] = 0;
1820   }
1821   return (int)v;
1822 }
1823 
1824 /*
1825 ** Return the SQL associated with a prepared statement
1826 */
1827 const char *sqlite3_sql(sqlite3_stmt *pStmt){
1828   Vdbe *p = (Vdbe *)pStmt;
1829   return p ? p->zSql : 0;
1830 }
1831 
1832 /*
1833 ** Return the SQL associated with a prepared statement with
1834 ** bound parameters expanded.  Space to hold the returned string is
1835 ** obtained from sqlite3_malloc().  The caller is responsible for
1836 ** freeing the returned string by passing it to sqlite3_free().
1837 **
1838 ** The SQLITE_TRACE_SIZE_LIMIT puts an upper bound on the size of
1839 ** expanded bound parameters.
1840 */
1841 char *sqlite3_expanded_sql(sqlite3_stmt *pStmt){
1842 #ifdef SQLITE_OMIT_TRACE
1843   return 0;
1844 #else
1845   char *z = 0;
1846   const char *zSql = sqlite3_sql(pStmt);
1847   if( zSql ){
1848     Vdbe *p = (Vdbe *)pStmt;
1849     sqlite3_mutex_enter(p->db->mutex);
1850     z = sqlite3VdbeExpandSql(p, zSql);
1851     sqlite3_mutex_leave(p->db->mutex);
1852   }
1853   return z;
1854 #endif
1855 }
1856 
1857 #ifdef SQLITE_ENABLE_NORMALIZE
1858 /*
1859 ** Return the normalized SQL associated with a prepared statement.
1860 */
1861 const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt){
1862   Vdbe *p = (Vdbe *)pStmt;
1863   if( p==0 ) return 0;
1864   if( p->zNormSql==0 && ALWAYS(p->zSql!=0) ){
1865     sqlite3_mutex_enter(p->db->mutex);
1866     p->zNormSql = sqlite3Normalize(p, p->zSql);
1867     sqlite3_mutex_leave(p->db->mutex);
1868   }
1869   return p->zNormSql;
1870 }
1871 #endif /* SQLITE_ENABLE_NORMALIZE */
1872 
1873 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1874 /*
1875 ** Allocate and populate an UnpackedRecord structure based on the serialized
1876 ** record in nKey/pKey. Return a pointer to the new UnpackedRecord structure
1877 ** if successful, or a NULL pointer if an OOM error is encountered.
1878 */
1879 static UnpackedRecord *vdbeUnpackRecord(
1880   KeyInfo *pKeyInfo,
1881   int nKey,
1882   const void *pKey
1883 ){
1884   UnpackedRecord *pRet;           /* Return value */
1885 
1886   pRet = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
1887   if( pRet ){
1888     memset(pRet->aMem, 0, sizeof(Mem)*(pKeyInfo->nKeyField+1));
1889     sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, pRet);
1890   }
1891   return pRet;
1892 }
1893 
1894 /*
1895 ** This function is called from within a pre-update callback to retrieve
1896 ** a field of the row currently being updated or deleted.
1897 */
1898 int sqlite3_preupdate_old(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
1899   PreUpdate *p = db->pPreUpdate;
1900   Mem *pMem;
1901   int rc = SQLITE_OK;
1902 
1903   /* Test that this call is being made from within an SQLITE_DELETE or
1904   ** SQLITE_UPDATE pre-update callback, and that iIdx is within range. */
1905   if( !p || p->op==SQLITE_INSERT ){
1906     rc = SQLITE_MISUSE_BKPT;
1907     goto preupdate_old_out;
1908   }
1909   if( p->pPk ){
1910     iIdx = sqlite3TableColumnToIndex(p->pPk, iIdx);
1911   }
1912   if( iIdx>=p->pCsr->nField || iIdx<0 ){
1913     rc = SQLITE_RANGE;
1914     goto preupdate_old_out;
1915   }
1916 
1917   /* If the old.* record has not yet been loaded into memory, do so now. */
1918   if( p->pUnpacked==0 ){
1919     u32 nRec;
1920     u8 *aRec;
1921 
1922     assert( p->pCsr->eCurType==CURTYPE_BTREE );
1923     nRec = sqlite3BtreePayloadSize(p->pCsr->uc.pCursor);
1924     aRec = sqlite3DbMallocRaw(db, nRec);
1925     if( !aRec ) goto preupdate_old_out;
1926     rc = sqlite3BtreePayload(p->pCsr->uc.pCursor, 0, nRec, aRec);
1927     if( rc==SQLITE_OK ){
1928       p->pUnpacked = vdbeUnpackRecord(&p->keyinfo, nRec, aRec);
1929       if( !p->pUnpacked ) rc = SQLITE_NOMEM;
1930     }
1931     if( rc!=SQLITE_OK ){
1932       sqlite3DbFree(db, aRec);
1933       goto preupdate_old_out;
1934     }
1935     p->aRecord = aRec;
1936   }
1937 
1938   pMem = *ppValue = &p->pUnpacked->aMem[iIdx];
1939   if( iIdx==p->pTab->iPKey ){
1940     sqlite3VdbeMemSetInt64(pMem, p->iKey1);
1941   }else if( iIdx>=p->pUnpacked->nField ){
1942     *ppValue = (sqlite3_value *)columnNullValue();
1943   }else if( p->pTab->aCol[iIdx].affinity==SQLITE_AFF_REAL ){
1944     if( pMem->flags & (MEM_Int|MEM_IntReal) ){
1945       testcase( pMem->flags & MEM_Int );
1946       testcase( pMem->flags & MEM_IntReal );
1947       sqlite3VdbeMemRealify(pMem);
1948     }
1949   }
1950 
1951  preupdate_old_out:
1952   sqlite3Error(db, rc);
1953   return sqlite3ApiExit(db, rc);
1954 }
1955 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
1956 
1957 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1958 /*
1959 ** This function is called from within a pre-update callback to retrieve
1960 ** the number of columns in the row being updated, deleted or inserted.
1961 */
1962 int sqlite3_preupdate_count(sqlite3 *db){
1963   PreUpdate *p = db->pPreUpdate;
1964   return (p ? p->keyinfo.nKeyField : 0);
1965 }
1966 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
1967 
1968 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1969 /*
1970 ** This function is designed to be called from within a pre-update callback
1971 ** only. It returns zero if the change that caused the callback was made
1972 ** immediately by a user SQL statement. Or, if the change was made by a
1973 ** trigger program, it returns the number of trigger programs currently
1974 ** on the stack (1 for a top-level trigger, 2 for a trigger fired by a
1975 ** top-level trigger etc.).
1976 **
1977 ** For the purposes of the previous paragraph, a foreign key CASCADE, SET NULL
1978 ** or SET DEFAULT action is considered a trigger.
1979 */
1980 int sqlite3_preupdate_depth(sqlite3 *db){
1981   PreUpdate *p = db->pPreUpdate;
1982   return (p ? p->v->nFrame : 0);
1983 }
1984 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
1985 
1986 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1987 /*
1988 ** This function is designed to be called from within a pre-update callback
1989 ** only.
1990 */
1991 int sqlite3_preupdate_blobwrite(sqlite3 *db){
1992   PreUpdate *p = db->pPreUpdate;
1993   return (p ? p->iBlobWrite : -1);
1994 }
1995 #endif
1996 
1997 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1998 /*
1999 ** This function is called from within a pre-update callback to retrieve
2000 ** a field of the row currently being updated or inserted.
2001 */
2002 int sqlite3_preupdate_new(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
2003   PreUpdate *p = db->pPreUpdate;
2004   int rc = SQLITE_OK;
2005   Mem *pMem;
2006 
2007   if( !p || p->op==SQLITE_DELETE ){
2008     rc = SQLITE_MISUSE_BKPT;
2009     goto preupdate_new_out;
2010   }
2011   if( p->pPk && p->op!=SQLITE_UPDATE ){
2012     iIdx = sqlite3TableColumnToIndex(p->pPk, iIdx);
2013   }
2014   if( iIdx>=p->pCsr->nField || iIdx<0 ){
2015     rc = SQLITE_RANGE;
2016     goto preupdate_new_out;
2017   }
2018 
2019   if( p->op==SQLITE_INSERT ){
2020     /* For an INSERT, memory cell p->iNewReg contains the serialized record
2021     ** that is being inserted. Deserialize it. */
2022     UnpackedRecord *pUnpack = p->pNewUnpacked;
2023     if( !pUnpack ){
2024       Mem *pData = &p->v->aMem[p->iNewReg];
2025       rc = ExpandBlob(pData);
2026       if( rc!=SQLITE_OK ) goto preupdate_new_out;
2027       pUnpack = vdbeUnpackRecord(&p->keyinfo, pData->n, pData->z);
2028       if( !pUnpack ){
2029         rc = SQLITE_NOMEM;
2030         goto preupdate_new_out;
2031       }
2032       p->pNewUnpacked = pUnpack;
2033     }
2034     pMem = &pUnpack->aMem[iIdx];
2035     if( iIdx==p->pTab->iPKey ){
2036       sqlite3VdbeMemSetInt64(pMem, p->iKey2);
2037     }else if( iIdx>=pUnpack->nField ){
2038       pMem = (sqlite3_value *)columnNullValue();
2039     }
2040   }else{
2041     /* For an UPDATE, memory cell (p->iNewReg+1+iIdx) contains the required
2042     ** value. Make a copy of the cell contents and return a pointer to it.
2043     ** It is not safe to return a pointer to the memory cell itself as the
2044     ** caller may modify the value text encoding.
2045     */
2046     assert( p->op==SQLITE_UPDATE );
2047     if( !p->aNew ){
2048       p->aNew = (Mem *)sqlite3DbMallocZero(db, sizeof(Mem) * p->pCsr->nField);
2049       if( !p->aNew ){
2050         rc = SQLITE_NOMEM;
2051         goto preupdate_new_out;
2052       }
2053     }
2054     assert( iIdx>=0 && iIdx<p->pCsr->nField );
2055     pMem = &p->aNew[iIdx];
2056     if( pMem->flags==0 ){
2057       if( iIdx==p->pTab->iPKey ){
2058         sqlite3VdbeMemSetInt64(pMem, p->iKey2);
2059       }else{
2060         rc = sqlite3VdbeMemCopy(pMem, &p->v->aMem[p->iNewReg+1+iIdx]);
2061         if( rc!=SQLITE_OK ) goto preupdate_new_out;
2062       }
2063     }
2064   }
2065   *ppValue = pMem;
2066 
2067  preupdate_new_out:
2068   sqlite3Error(db, rc);
2069   return sqlite3ApiExit(db, rc);
2070 }
2071 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2072 
2073 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS
2074 /*
2075 ** Return status data for a single loop within query pStmt.
2076 */
2077 int sqlite3_stmt_scanstatus(
2078   sqlite3_stmt *pStmt,            /* Prepared statement being queried */
2079   int idx,                        /* Index of loop to report on */
2080   int iScanStatusOp,              /* Which metric to return */
2081   void *pOut                      /* OUT: Write the answer here */
2082 ){
2083   Vdbe *p = (Vdbe*)pStmt;
2084   ScanStatus *pScan;
2085   if( idx<0 || idx>=p->nScan ) return 1;
2086   pScan = &p->aScan[idx];
2087   switch( iScanStatusOp ){
2088     case SQLITE_SCANSTAT_NLOOP: {
2089       *(sqlite3_int64*)pOut = p->anExec[pScan->addrLoop];
2090       break;
2091     }
2092     case SQLITE_SCANSTAT_NVISIT: {
2093       *(sqlite3_int64*)pOut = p->anExec[pScan->addrVisit];
2094       break;
2095     }
2096     case SQLITE_SCANSTAT_EST: {
2097       double r = 1.0;
2098       LogEst x = pScan->nEst;
2099       while( x<100 ){
2100         x += 10;
2101         r *= 0.5;
2102       }
2103       *(double*)pOut = r*sqlite3LogEstToInt(x);
2104       break;
2105     }
2106     case SQLITE_SCANSTAT_NAME: {
2107       *(const char**)pOut = pScan->zName;
2108       break;
2109     }
2110     case SQLITE_SCANSTAT_EXPLAIN: {
2111       if( pScan->addrExplain ){
2112         *(const char**)pOut = p->aOp[ pScan->addrExplain ].p4.z;
2113       }else{
2114         *(const char**)pOut = 0;
2115       }
2116       break;
2117     }
2118     case SQLITE_SCANSTAT_SELECTID: {
2119       if( pScan->addrExplain ){
2120         *(int*)pOut = p->aOp[ pScan->addrExplain ].p1;
2121       }else{
2122         *(int*)pOut = -1;
2123       }
2124       break;
2125     }
2126     default: {
2127       return 1;
2128     }
2129   }
2130   return 0;
2131 }
2132 
2133 /*
2134 ** Zero all counters associated with the sqlite3_stmt_scanstatus() data.
2135 */
2136 void sqlite3_stmt_scanstatus_reset(sqlite3_stmt *pStmt){
2137   Vdbe *p = (Vdbe*)pStmt;
2138   memset(p->anExec, 0, p->nOp * sizeof(i64));
2139 }
2140 #endif /* SQLITE_ENABLE_STMT_SCANSTATUS */
2141