xref: /sqlite-3.40.0/src/util.c (revision f71a243a)
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 ** Utility functions used throughout sqlite.
13 **
14 ** This file contains functions for allocating memory, comparing
15 ** strings, and stuff like that.
16 **
17 */
18 #include "sqliteInt.h"
19 #include <stdarg.h>
20 #include <math.h>
21 
22 /*
23 ** Routine needed to support the testcase() macro.
24 */
25 #ifdef SQLITE_COVERAGE_TEST
26 void sqlite3Coverage(int x){
27   static unsigned dummy = 0;
28   dummy += (unsigned)x;
29 }
30 #endif
31 
32 /*
33 ** Calls to sqlite3FaultSim() are used to simulate a failure during testing,
34 ** or to bypass normal error detection during testing in order to let
35 ** execute proceed futher downstream.
36 **
37 ** In deployment, sqlite3FaultSim() *always* return SQLITE_OK (0).  The
38 ** sqlite3FaultSim() function only returns non-zero during testing.
39 **
40 ** During testing, if the test harness has set a fault-sim callback using
41 ** a call to sqlite3_test_control(SQLITE_TESTCTRL_FAULT_INSTALL), then
42 ** each call to sqlite3FaultSim() is relayed to that application-supplied
43 ** callback and the integer return value form the application-supplied
44 ** callback is returned by sqlite3FaultSim().
45 **
46 ** The integer argument to sqlite3FaultSim() is a code to identify which
47 ** sqlite3FaultSim() instance is being invoked. Each call to sqlite3FaultSim()
48 ** should have a unique code.  To prevent legacy testing applications from
49 ** breaking, the codes should not be changed or reused.
50 */
51 #ifndef SQLITE_UNTESTABLE
52 int sqlite3FaultSim(int iTest){
53   int (*xCallback)(int) = sqlite3GlobalConfig.xTestCallback;
54   return xCallback ? xCallback(iTest) : SQLITE_OK;
55 }
56 #endif
57 
58 #ifndef SQLITE_OMIT_FLOATING_POINT
59 /*
60 ** Return true if the floating point value is Not a Number (NaN).
61 */
62 int sqlite3IsNaN(double x){
63   u64 y;
64   memcpy(&y,&x,sizeof(y));
65   return IsNaN(y);
66 }
67 #endif /* SQLITE_OMIT_FLOATING_POINT */
68 
69 /*
70 ** Compute a string length that is limited to what can be stored in
71 ** lower 30 bits of a 32-bit signed integer.
72 **
73 ** The value returned will never be negative.  Nor will it ever be greater
74 ** than the actual length of the string.  For very long strings (greater
75 ** than 1GiB) the value returned might be less than the true string length.
76 */
77 int sqlite3Strlen30(const char *z){
78   if( z==0 ) return 0;
79   return 0x3fffffff & (int)strlen(z);
80 }
81 
82 /*
83 ** Return the declared type of a column.  Or return zDflt if the column
84 ** has no declared type.
85 **
86 ** The column type is an extra string stored after the zero-terminator on
87 ** the column name if and only if the COLFLAG_HASTYPE flag is set.
88 */
89 char *sqlite3ColumnType(Column *pCol, char *zDflt){
90   if( (pCol->colFlags & COLFLAG_HASTYPE)==0 ) return zDflt;
91   return pCol->zName + strlen(pCol->zName) + 1;
92 }
93 
94 /*
95 ** Helper function for sqlite3Error() - called rarely.  Broken out into
96 ** a separate routine to avoid unnecessary register saves on entry to
97 ** sqlite3Error().
98 */
99 static SQLITE_NOINLINE void  sqlite3ErrorFinish(sqlite3 *db, int err_code){
100   if( db->pErr ) sqlite3ValueSetNull(db->pErr);
101   sqlite3SystemError(db, err_code);
102 }
103 
104 /*
105 ** Set the current error code to err_code and clear any prior error message.
106 ** Also set iSysErrno (by calling sqlite3System) if the err_code indicates
107 ** that would be appropriate.
108 */
109 void sqlite3Error(sqlite3 *db, int err_code){
110   assert( db!=0 );
111   db->errCode = err_code;
112   if( err_code || db->pErr ) sqlite3ErrorFinish(db, err_code);
113 }
114 
115 /*
116 ** Load the sqlite3.iSysErrno field if that is an appropriate thing
117 ** to do based on the SQLite error code in rc.
118 */
119 void sqlite3SystemError(sqlite3 *db, int rc){
120   if( rc==SQLITE_IOERR_NOMEM ) return;
121   rc &= 0xff;
122   if( rc==SQLITE_CANTOPEN || rc==SQLITE_IOERR ){
123     db->iSysErrno = sqlite3OsGetLastError(db->pVfs);
124   }
125 }
126 
127 /*
128 ** Set the most recent error code and error string for the sqlite
129 ** handle "db". The error code is set to "err_code".
130 **
131 ** If it is not NULL, string zFormat specifies the format of the
132 ** error string in the style of the printf functions: The following
133 ** format characters are allowed:
134 **
135 **      %s      Insert a string
136 **      %z      A string that should be freed after use
137 **      %d      Insert an integer
138 **      %T      Insert a token
139 **      %S      Insert the first element of a SrcList
140 **
141 ** zFormat and any string tokens that follow it are assumed to be
142 ** encoded in UTF-8.
143 **
144 ** To clear the most recent error for sqlite handle "db", sqlite3Error
145 ** should be called with err_code set to SQLITE_OK and zFormat set
146 ** to NULL.
147 */
148 void sqlite3ErrorWithMsg(sqlite3 *db, int err_code, const char *zFormat, ...){
149   assert( db!=0 );
150   db->errCode = err_code;
151   sqlite3SystemError(db, err_code);
152   if( zFormat==0 ){
153     sqlite3Error(db, err_code);
154   }else if( db->pErr || (db->pErr = sqlite3ValueNew(db))!=0 ){
155     char *z;
156     va_list ap;
157     va_start(ap, zFormat);
158     z = sqlite3VMPrintf(db, zFormat, ap);
159     va_end(ap);
160     sqlite3ValueSetStr(db->pErr, -1, z, SQLITE_UTF8, SQLITE_DYNAMIC);
161   }
162 }
163 
164 /*
165 ** Add an error message to pParse->zErrMsg and increment pParse->nErr.
166 ** The following formatting characters are allowed:
167 **
168 **      %s      Insert a string
169 **      %z      A string that should be freed after use
170 **      %d      Insert an integer
171 **      %T      Insert a token
172 **      %S      Insert the first element of a SrcList
173 **
174 ** This function should be used to report any error that occurs while
175 ** compiling an SQL statement (i.e. within sqlite3_prepare()). The
176 ** last thing the sqlite3_prepare() function does is copy the error
177 ** stored by this function into the database handle using sqlite3Error().
178 ** Functions sqlite3Error() or sqlite3ErrorWithMsg() should be used
179 ** during statement execution (sqlite3_step() etc.).
180 */
181 void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
182   char *zMsg;
183   va_list ap;
184   sqlite3 *db = pParse->db;
185   va_start(ap, zFormat);
186   zMsg = sqlite3VMPrintf(db, zFormat, ap);
187   va_end(ap);
188   if( db->suppressErr ){
189     sqlite3DbFree(db, zMsg);
190   }else{
191     pParse->nErr++;
192     sqlite3DbFree(db, pParse->zErrMsg);
193     pParse->zErrMsg = zMsg;
194     pParse->rc = SQLITE_ERROR;
195   }
196 }
197 
198 /*
199 ** If database connection db is currently parsing SQL, then transfer
200 ** error code errCode to that parser if the parser has not already
201 ** encountered some other kind of error.
202 */
203 int sqlite3ErrorToParser(sqlite3 *db, int errCode){
204   Parse *pParse;
205   if( db==0 || (pParse = db->pParse)==0 ) return errCode;
206   pParse->rc = errCode;
207   pParse->nErr++;
208   return errCode;
209 }
210 
211 /*
212 ** Convert an SQL-style quoted string into a normal string by removing
213 ** the quote characters.  The conversion is done in-place.  If the
214 ** input does not begin with a quote character, then this routine
215 ** is a no-op.
216 **
217 ** The input string must be zero-terminated.  A new zero-terminator
218 ** is added to the dequoted string.
219 **
220 ** The return value is -1 if no dequoting occurs or the length of the
221 ** dequoted string, exclusive of the zero terminator, if dequoting does
222 ** occur.
223 **
224 ** 2002-02-14: This routine is extended to remove MS-Access style
225 ** brackets from around identifiers.  For example:  "[a-b-c]" becomes
226 ** "a-b-c".
227 */
228 void sqlite3Dequote(char *z){
229   char quote;
230   int i, j;
231   if( z==0 ) return;
232   quote = z[0];
233   if( !sqlite3Isquote(quote) ) return;
234   if( quote=='[' ) quote = ']';
235   for(i=1, j=0;; i++){
236     assert( z[i] );
237     if( z[i]==quote ){
238       if( z[i+1]==quote ){
239         z[j++] = quote;
240         i++;
241       }else{
242         break;
243       }
244     }else{
245       z[j++] = z[i];
246     }
247   }
248   z[j] = 0;
249 }
250 void sqlite3DequoteExpr(Expr *p){
251   assert( sqlite3Isquote(p->u.zToken[0]) );
252   p->flags |= p->u.zToken[0]=='"' ? EP_Quoted|EP_DblQuoted : EP_Quoted;
253   sqlite3Dequote(p->u.zToken);
254 }
255 
256 /*
257 ** Generate a Token object from a string
258 */
259 void sqlite3TokenInit(Token *p, char *z){
260   p->z = z;
261   p->n = sqlite3Strlen30(z);
262 }
263 
264 /* Convenient short-hand */
265 #define UpperToLower sqlite3UpperToLower
266 
267 /*
268 ** Some systems have stricmp().  Others have strcasecmp().  Because
269 ** there is no consistency, we will define our own.
270 **
271 ** IMPLEMENTATION-OF: R-30243-02494 The sqlite3_stricmp() and
272 ** sqlite3_strnicmp() APIs allow applications and extensions to compare
273 ** the contents of two buffers containing UTF-8 strings in a
274 ** case-independent fashion, using the same definition of "case
275 ** independence" that SQLite uses internally when comparing identifiers.
276 */
277 int sqlite3_stricmp(const char *zLeft, const char *zRight){
278   if( zLeft==0 ){
279     return zRight ? -1 : 0;
280   }else if( zRight==0 ){
281     return 1;
282   }
283   return sqlite3StrICmp(zLeft, zRight);
284 }
285 int sqlite3StrICmp(const char *zLeft, const char *zRight){
286   unsigned char *a, *b;
287   int c, x;
288   a = (unsigned char *)zLeft;
289   b = (unsigned char *)zRight;
290   for(;;){
291     c = *a;
292     x = *b;
293     if( c==x ){
294       if( c==0 ) break;
295     }else{
296       c = (int)UpperToLower[c] - (int)UpperToLower[x];
297       if( c ) break;
298     }
299     a++;
300     b++;
301   }
302   return c;
303 }
304 int sqlite3_strnicmp(const char *zLeft, const char *zRight, int N){
305   register unsigned char *a, *b;
306   if( zLeft==0 ){
307     return zRight ? -1 : 0;
308   }else if( zRight==0 ){
309     return 1;
310   }
311   a = (unsigned char *)zLeft;
312   b = (unsigned char *)zRight;
313   while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
314   return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
315 }
316 
317 /*
318 ** Compute 10 to the E-th power.  Examples:  E==1 results in 10.
319 ** E==2 results in 100.  E==50 results in 1.0e50.
320 **
321 ** This routine only works for values of E between 1 and 341.
322 */
323 static LONGDOUBLE_TYPE sqlite3Pow10(int E){
324 #if defined(_MSC_VER)
325   static const LONGDOUBLE_TYPE x[] = {
326     1.0e+001L,
327     1.0e+002L,
328     1.0e+004L,
329     1.0e+008L,
330     1.0e+016L,
331     1.0e+032L,
332     1.0e+064L,
333     1.0e+128L,
334     1.0e+256L
335   };
336   LONGDOUBLE_TYPE r = 1.0;
337   int i;
338   assert( E>=0 && E<=307 );
339   for(i=0; E!=0; i++, E >>=1){
340     if( E & 1 ) r *= x[i];
341   }
342   return r;
343 #else
344   LONGDOUBLE_TYPE x = 10.0;
345   LONGDOUBLE_TYPE r = 1.0;
346   while(1){
347     if( E & 1 ) r *= x;
348     E >>= 1;
349     if( E==0 ) break;
350     x *= x;
351   }
352   return r;
353 #endif
354 }
355 
356 /*
357 ** The string z[] is an text representation of a real number.
358 ** Convert this string to a double and write it into *pResult.
359 **
360 ** The string z[] is length bytes in length (bytes, not characters) and
361 ** uses the encoding enc.  The string is not necessarily zero-terminated.
362 **
363 ** Return TRUE if the result is a valid real number (or integer) and FALSE
364 ** if the string is empty or contains extraneous text.  More specifically
365 ** return
366 **      1          =>  The input string is a pure integer
367 **      2 or more  =>  The input has a decimal point or eNNN clause
368 **      0 or less  =>  The input string is not a valid number
369 **     -1          =>  Not a valid number, but has a valid prefix which
370 **                     includes a decimal point and/or an eNNN clause
371 **
372 ** Valid numbers are in one of these formats:
373 **
374 **    [+-]digits[E[+-]digits]
375 **    [+-]digits.[digits][E[+-]digits]
376 **    [+-].digits[E[+-]digits]
377 **
378 ** Leading and trailing whitespace is ignored for the purpose of determining
379 ** validity.
380 **
381 ** If some prefix of the input string is a valid number, this routine
382 ** returns FALSE but it still converts the prefix and writes the result
383 ** into *pResult.
384 */
385 int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
386 #ifndef SQLITE_OMIT_FLOATING_POINT
387   int incr;
388   const char *zEnd = z + length;
389   /* sign * significand * (10 ^ (esign * exponent)) */
390   int sign = 1;    /* sign of significand */
391   i64 s = 0;       /* significand */
392   int d = 0;       /* adjust exponent for shifting decimal point */
393   int esign = 1;   /* sign of exponent */
394   int e = 0;       /* exponent */
395   int eValid = 1;  /* True exponent is either not used or is well-formed */
396   double result;
397   int nDigit = 0;  /* Number of digits processed */
398   int eType = 1;   /* 1: pure integer,  2+: fractional  -1 or less: bad UTF16 */
399 
400   assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
401   *pResult = 0.0;   /* Default return value, in case of an error */
402 
403   if( enc==SQLITE_UTF8 ){
404     incr = 1;
405   }else{
406     int i;
407     incr = 2;
408     assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
409     testcase( enc==SQLITE_UTF16LE );
410     testcase( enc==SQLITE_UTF16BE );
411     for(i=3-enc; i<length && z[i]==0; i+=2){}
412     if( i<length ) eType = -100;
413     zEnd = &z[i^1];
414     z += (enc&1);
415   }
416 
417   /* skip leading spaces */
418   while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
419   if( z>=zEnd ) return 0;
420 
421   /* get sign of significand */
422   if( *z=='-' ){
423     sign = -1;
424     z+=incr;
425   }else if( *z=='+' ){
426     z+=incr;
427   }
428 
429   /* copy max significant digits to significand */
430   while( z<zEnd && sqlite3Isdigit(*z) ){
431     s = s*10 + (*z - '0');
432     z+=incr; nDigit++;
433     if( s>=((LARGEST_INT64-9)/10) ){
434       /* skip non-significant significand digits
435       ** (increase exponent by d to shift decimal left) */
436       while( z<zEnd && sqlite3Isdigit(*z) ){ z+=incr; d++; }
437     }
438   }
439   if( z>=zEnd ) goto do_atof_calc;
440 
441   /* if decimal point is present */
442   if( *z=='.' ){
443     z+=incr;
444     eType++;
445     /* copy digits from after decimal to significand
446     ** (decrease exponent by d to shift decimal right) */
447     while( z<zEnd && sqlite3Isdigit(*z) ){
448       if( s<((LARGEST_INT64-9)/10) ){
449         s = s*10 + (*z - '0');
450         d--;
451         nDigit++;
452       }
453       z+=incr;
454     }
455   }
456   if( z>=zEnd ) goto do_atof_calc;
457 
458   /* if exponent is present */
459   if( *z=='e' || *z=='E' ){
460     z+=incr;
461     eValid = 0;
462     eType++;
463 
464     /* This branch is needed to avoid a (harmless) buffer overread.  The
465     ** special comment alerts the mutation tester that the correct answer
466     ** is obtained even if the branch is omitted */
467     if( z>=zEnd ) goto do_atof_calc;              /*PREVENTS-HARMLESS-OVERREAD*/
468 
469     /* get sign of exponent */
470     if( *z=='-' ){
471       esign = -1;
472       z+=incr;
473     }else if( *z=='+' ){
474       z+=incr;
475     }
476     /* copy digits to exponent */
477     while( z<zEnd && sqlite3Isdigit(*z) ){
478       e = e<10000 ? (e*10 + (*z - '0')) : 10000;
479       z+=incr;
480       eValid = 1;
481     }
482   }
483 
484   /* skip trailing spaces */
485   while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
486 
487 do_atof_calc:
488   /* adjust exponent by d, and update sign */
489   e = (e*esign) + d;
490   if( e<0 ) {
491     esign = -1;
492     e *= -1;
493   } else {
494     esign = 1;
495   }
496 
497   if( s==0 ) {
498     /* In the IEEE 754 standard, zero is signed. */
499     result = sign<0 ? -(double)0 : (double)0;
500   } else {
501     /* Attempt to reduce exponent.
502     **
503     ** Branches that are not required for the correct answer but which only
504     ** help to obtain the correct answer faster are marked with special
505     ** comments, as a hint to the mutation tester.
506     */
507     while( e>0 ){                                       /*OPTIMIZATION-IF-TRUE*/
508       if( esign>0 ){
509         if( s>=(LARGEST_INT64/10) ) break;             /*OPTIMIZATION-IF-FALSE*/
510         s *= 10;
511       }else{
512         if( s%10!=0 ) break;                           /*OPTIMIZATION-IF-FALSE*/
513         s /= 10;
514       }
515       e--;
516     }
517 
518     /* adjust the sign of significand */
519     s = sign<0 ? -s : s;
520 
521     if( e==0 ){                                         /*OPTIMIZATION-IF-TRUE*/
522       result = (double)s;
523     }else{
524       /* attempt to handle extremely small/large numbers better */
525       if( e>307 ){                                      /*OPTIMIZATION-IF-TRUE*/
526         if( e<342 ){                                    /*OPTIMIZATION-IF-TRUE*/
527           LONGDOUBLE_TYPE scale = sqlite3Pow10(e-308);
528           if( esign<0 ){
529             result = s / scale;
530             result /= 1.0e+308;
531           }else{
532             result = s * scale;
533             result *= 1.0e+308;
534           }
535         }else{ assert( e>=342 );
536           if( esign<0 ){
537             result = 0.0*s;
538           }else{
539 #ifdef INFINITY
540             result = INFINITY*s;
541 #else
542             result = 1e308*1e308*s;  /* Infinity */
543 #endif
544           }
545         }
546       }else{
547         LONGDOUBLE_TYPE scale = sqlite3Pow10(e);
548         if( esign<0 ){
549           result = s / scale;
550         }else{
551           result = s * scale;
552         }
553       }
554     }
555   }
556 
557   /* store the result */
558   *pResult = result;
559 
560   /* return true if number and no extra non-whitespace chracters after */
561   if( z==zEnd && nDigit>0 && eValid && eType>0 ){
562     return eType;
563   }else if( eType>=2 && (eType==3 || eValid) && nDigit>0 ){
564     return -1;
565   }else{
566     return 0;
567   }
568 #else
569   return !sqlite3Atoi64(z, pResult, length, enc);
570 #endif /* SQLITE_OMIT_FLOATING_POINT */
571 }
572 
573 /*
574 ** Compare the 19-character string zNum against the text representation
575 ** value 2^63:  9223372036854775808.  Return negative, zero, or positive
576 ** if zNum is less than, equal to, or greater than the string.
577 ** Note that zNum must contain exactly 19 characters.
578 **
579 ** Unlike memcmp() this routine is guaranteed to return the difference
580 ** in the values of the last digit if the only difference is in the
581 ** last digit.  So, for example,
582 **
583 **      compare2pow63("9223372036854775800", 1)
584 **
585 ** will return -8.
586 */
587 static int compare2pow63(const char *zNum, int incr){
588   int c = 0;
589   int i;
590                     /* 012345678901234567 */
591   const char *pow63 = "922337203685477580";
592   for(i=0; c==0 && i<18; i++){
593     c = (zNum[i*incr]-pow63[i])*10;
594   }
595   if( c==0 ){
596     c = zNum[18*incr] - '8';
597     testcase( c==(-1) );
598     testcase( c==0 );
599     testcase( c==(+1) );
600   }
601   return c;
602 }
603 
604 /*
605 ** Convert zNum to a 64-bit signed integer.  zNum must be decimal. This
606 ** routine does *not* accept hexadecimal notation.
607 **
608 ** Returns:
609 **
610 **    -1    Not even a prefix of the input text looks like an integer
611 **     0    Successful transformation.  Fits in a 64-bit signed integer.
612 **     1    Excess non-space text after the integer value
613 **     2    Integer too large for a 64-bit signed integer or is malformed
614 **     3    Special case of 9223372036854775808
615 **
616 ** length is the number of bytes in the string (bytes, not characters).
617 ** The string is not necessarily zero-terminated.  The encoding is
618 ** given by enc.
619 */
620 int sqlite3Atoi64(const char *zNum, i64 *pNum, int length, u8 enc){
621   int incr;
622   u64 u = 0;
623   int neg = 0; /* assume positive */
624   int i;
625   int c = 0;
626   int nonNum = 0;  /* True if input contains UTF16 with high byte non-zero */
627   int rc;          /* Baseline return code */
628   const char *zStart;
629   const char *zEnd = zNum + length;
630   assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
631   if( enc==SQLITE_UTF8 ){
632     incr = 1;
633   }else{
634     incr = 2;
635     assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
636     for(i=3-enc; i<length && zNum[i]==0; i+=2){}
637     nonNum = i<length;
638     zEnd = &zNum[i^1];
639     zNum += (enc&1);
640   }
641   while( zNum<zEnd && sqlite3Isspace(*zNum) ) zNum+=incr;
642   if( zNum<zEnd ){
643     if( *zNum=='-' ){
644       neg = 1;
645       zNum+=incr;
646     }else if( *zNum=='+' ){
647       zNum+=incr;
648     }
649   }
650   zStart = zNum;
651   while( zNum<zEnd && zNum[0]=='0' ){ zNum+=incr; } /* Skip leading zeros. */
652   for(i=0; &zNum[i]<zEnd && (c=zNum[i])>='0' && c<='9'; i+=incr){
653     u = u*10 + c - '0';
654   }
655   testcase( i==18*incr );
656   testcase( i==19*incr );
657   testcase( i==20*incr );
658   if( u>LARGEST_INT64 ){
659     /* This test and assignment is needed only to suppress UB warnings
660     ** from clang and -fsanitize=undefined.  This test and assignment make
661     ** the code a little larger and slower, and no harm comes from omitting
662     ** them, but we must appaise the undefined-behavior pharisees. */
663     *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
664   }else if( neg ){
665     *pNum = -(i64)u;
666   }else{
667     *pNum = (i64)u;
668   }
669   rc = 0;
670   if( i==0 && zStart==zNum ){    /* No digits */
671     rc = -1;
672   }else if( nonNum ){            /* UTF16 with high-order bytes non-zero */
673     rc = 1;
674   }else if( &zNum[i]<zEnd ){     /* Extra bytes at the end */
675     int jj = i;
676     do{
677       if( !sqlite3Isspace(zNum[jj]) ){
678         rc = 1;          /* Extra non-space text after the integer */
679         break;
680       }
681       jj += incr;
682     }while( &zNum[jj]<zEnd );
683   }
684   if( i<19*incr ){
685     /* Less than 19 digits, so we know that it fits in 64 bits */
686     assert( u<=LARGEST_INT64 );
687     return rc;
688   }else{
689     /* zNum is a 19-digit numbers.  Compare it against 9223372036854775808. */
690     c = i>19*incr ? 1 : compare2pow63(zNum, incr);
691     if( c<0 ){
692       /* zNum is less than 9223372036854775808 so it fits */
693       assert( u<=LARGEST_INT64 );
694       return rc;
695     }else{
696       *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
697       if( c>0 ){
698         /* zNum is greater than 9223372036854775808 so it overflows */
699         return 2;
700       }else{
701         /* zNum is exactly 9223372036854775808.  Fits if negative.  The
702         ** special case 2 overflow if positive */
703         assert( u-1==LARGEST_INT64 );
704         return neg ? rc : 3;
705       }
706     }
707   }
708 }
709 
710 /*
711 ** Transform a UTF-8 integer literal, in either decimal or hexadecimal,
712 ** into a 64-bit signed integer.  This routine accepts hexadecimal literals,
713 ** whereas sqlite3Atoi64() does not.
714 **
715 ** Returns:
716 **
717 **     0    Successful transformation.  Fits in a 64-bit signed integer.
718 **     1    Excess text after the integer value
719 **     2    Integer too large for a 64-bit signed integer or is malformed
720 **     3    Special case of 9223372036854775808
721 */
722 int sqlite3DecOrHexToI64(const char *z, i64 *pOut){
723 #ifndef SQLITE_OMIT_HEX_INTEGER
724   if( z[0]=='0'
725    && (z[1]=='x' || z[1]=='X')
726   ){
727     u64 u = 0;
728     int i, k;
729     for(i=2; z[i]=='0'; i++){}
730     for(k=i; sqlite3Isxdigit(z[k]); k++){
731       u = u*16 + sqlite3HexToInt(z[k]);
732     }
733     memcpy(pOut, &u, 8);
734     return (z[k]==0 && k-i<=16) ? 0 : 2;
735   }else
736 #endif /* SQLITE_OMIT_HEX_INTEGER */
737   {
738     return sqlite3Atoi64(z, pOut, sqlite3Strlen30(z), SQLITE_UTF8);
739   }
740 }
741 
742 /*
743 ** If zNum represents an integer that will fit in 32-bits, then set
744 ** *pValue to that integer and return true.  Otherwise return false.
745 **
746 ** This routine accepts both decimal and hexadecimal notation for integers.
747 **
748 ** Any non-numeric characters that following zNum are ignored.
749 ** This is different from sqlite3Atoi64() which requires the
750 ** input number to be zero-terminated.
751 */
752 int sqlite3GetInt32(const char *zNum, int *pValue){
753   sqlite_int64 v = 0;
754   int i, c;
755   int neg = 0;
756   if( zNum[0]=='-' ){
757     neg = 1;
758     zNum++;
759   }else if( zNum[0]=='+' ){
760     zNum++;
761   }
762 #ifndef SQLITE_OMIT_HEX_INTEGER
763   else if( zNum[0]=='0'
764         && (zNum[1]=='x' || zNum[1]=='X')
765         && sqlite3Isxdigit(zNum[2])
766   ){
767     u32 u = 0;
768     zNum += 2;
769     while( zNum[0]=='0' ) zNum++;
770     for(i=0; sqlite3Isxdigit(zNum[i]) && i<8; i++){
771       u = u*16 + sqlite3HexToInt(zNum[i]);
772     }
773     if( (u&0x80000000)==0 && sqlite3Isxdigit(zNum[i])==0 ){
774       memcpy(pValue, &u, 4);
775       return 1;
776     }else{
777       return 0;
778     }
779   }
780 #endif
781   if( !sqlite3Isdigit(zNum[0]) ) return 0;
782   while( zNum[0]=='0' ) zNum++;
783   for(i=0; i<11 && (c = zNum[i] - '0')>=0 && c<=9; i++){
784     v = v*10 + c;
785   }
786 
787   /* The longest decimal representation of a 32 bit integer is 10 digits:
788   **
789   **             1234567890
790   **     2^31 -> 2147483648
791   */
792   testcase( i==10 );
793   if( i>10 ){
794     return 0;
795   }
796   testcase( v-neg==2147483647 );
797   if( v-neg>2147483647 ){
798     return 0;
799   }
800   if( neg ){
801     v = -v;
802   }
803   *pValue = (int)v;
804   return 1;
805 }
806 
807 /*
808 ** Return a 32-bit integer value extracted from a string.  If the
809 ** string is not an integer, just return 0.
810 */
811 int sqlite3Atoi(const char *z){
812   int x = 0;
813   if( z ) sqlite3GetInt32(z, &x);
814   return x;
815 }
816 
817 /*
818 ** The variable-length integer encoding is as follows:
819 **
820 ** KEY:
821 **         A = 0xxxxxxx    7 bits of data and one flag bit
822 **         B = 1xxxxxxx    7 bits of data and one flag bit
823 **         C = xxxxxxxx    8 bits of data
824 **
825 **  7 bits - A
826 ** 14 bits - BA
827 ** 21 bits - BBA
828 ** 28 bits - BBBA
829 ** 35 bits - BBBBA
830 ** 42 bits - BBBBBA
831 ** 49 bits - BBBBBBA
832 ** 56 bits - BBBBBBBA
833 ** 64 bits - BBBBBBBBC
834 */
835 
836 /*
837 ** Write a 64-bit variable-length integer to memory starting at p[0].
838 ** The length of data write will be between 1 and 9 bytes.  The number
839 ** of bytes written is returned.
840 **
841 ** A variable-length integer consists of the lower 7 bits of each byte
842 ** for all bytes that have the 8th bit set and one byte with the 8th
843 ** bit clear.  Except, if we get to the 9th byte, it stores the full
844 ** 8 bits and is the last byte.
845 */
846 static int SQLITE_NOINLINE putVarint64(unsigned char *p, u64 v){
847   int i, j, n;
848   u8 buf[10];
849   if( v & (((u64)0xff000000)<<32) ){
850     p[8] = (u8)v;
851     v >>= 8;
852     for(i=7; i>=0; i--){
853       p[i] = (u8)((v & 0x7f) | 0x80);
854       v >>= 7;
855     }
856     return 9;
857   }
858   n = 0;
859   do{
860     buf[n++] = (u8)((v & 0x7f) | 0x80);
861     v >>= 7;
862   }while( v!=0 );
863   buf[0] &= 0x7f;
864   assert( n<=9 );
865   for(i=0, j=n-1; j>=0; j--, i++){
866     p[i] = buf[j];
867   }
868   return n;
869 }
870 int sqlite3PutVarint(unsigned char *p, u64 v){
871   if( v<=0x7f ){
872     p[0] = v&0x7f;
873     return 1;
874   }
875   if( v<=0x3fff ){
876     p[0] = ((v>>7)&0x7f)|0x80;
877     p[1] = v&0x7f;
878     return 2;
879   }
880   return putVarint64(p,v);
881 }
882 
883 /*
884 ** Bitmasks used by sqlite3GetVarint().  These precomputed constants
885 ** are defined here rather than simply putting the constant expressions
886 ** inline in order to work around bugs in the RVT compiler.
887 **
888 ** SLOT_2_0     A mask for  (0x7f<<14) | 0x7f
889 **
890 ** SLOT_4_2_0   A mask for  (0x7f<<28) | SLOT_2_0
891 */
892 #define SLOT_2_0     0x001fc07f
893 #define SLOT_4_2_0   0xf01fc07f
894 
895 
896 /*
897 ** Read a 64-bit variable-length integer from memory starting at p[0].
898 ** Return the number of bytes read.  The value is stored in *v.
899 */
900 u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
901   u32 a,b,s;
902 
903   if( ((signed char*)p)[0]>=0 ){
904     *v = *p;
905     return 1;
906   }
907   if( ((signed char*)p)[1]>=0 ){
908     *v = ((u32)(p[0]&0x7f)<<7) | p[1];
909     return 2;
910   }
911 
912   /* Verify that constants are precomputed correctly */
913   assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
914   assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
915 
916   a = ((u32)p[0])<<14;
917   b = p[1];
918   p += 2;
919   a |= *p;
920   /* a: p0<<14 | p2 (unmasked) */
921   if (!(a&0x80))
922   {
923     a &= SLOT_2_0;
924     b &= 0x7f;
925     b = b<<7;
926     a |= b;
927     *v = a;
928     return 3;
929   }
930 
931   /* CSE1 from below */
932   a &= SLOT_2_0;
933   p++;
934   b = b<<14;
935   b |= *p;
936   /* b: p1<<14 | p3 (unmasked) */
937   if (!(b&0x80))
938   {
939     b &= SLOT_2_0;
940     /* moved CSE1 up */
941     /* a &= (0x7f<<14)|(0x7f); */
942     a = a<<7;
943     a |= b;
944     *v = a;
945     return 4;
946   }
947 
948   /* a: p0<<14 | p2 (masked) */
949   /* b: p1<<14 | p3 (unmasked) */
950   /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
951   /* moved CSE1 up */
952   /* a &= (0x7f<<14)|(0x7f); */
953   b &= SLOT_2_0;
954   s = a;
955   /* s: p0<<14 | p2 (masked) */
956 
957   p++;
958   a = a<<14;
959   a |= *p;
960   /* a: p0<<28 | p2<<14 | p4 (unmasked) */
961   if (!(a&0x80))
962   {
963     /* we can skip these cause they were (effectively) done above
964     ** while calculating s */
965     /* a &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
966     /* b &= (0x7f<<14)|(0x7f); */
967     b = b<<7;
968     a |= b;
969     s = s>>18;
970     *v = ((u64)s)<<32 | a;
971     return 5;
972   }
973 
974   /* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
975   s = s<<7;
976   s |= b;
977   /* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
978 
979   p++;
980   b = b<<14;
981   b |= *p;
982   /* b: p1<<28 | p3<<14 | p5 (unmasked) */
983   if (!(b&0x80))
984   {
985     /* we can skip this cause it was (effectively) done above in calc'ing s */
986     /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
987     a &= SLOT_2_0;
988     a = a<<7;
989     a |= b;
990     s = s>>18;
991     *v = ((u64)s)<<32 | a;
992     return 6;
993   }
994 
995   p++;
996   a = a<<14;
997   a |= *p;
998   /* a: p2<<28 | p4<<14 | p6 (unmasked) */
999   if (!(a&0x80))
1000   {
1001     a &= SLOT_4_2_0;
1002     b &= SLOT_2_0;
1003     b = b<<7;
1004     a |= b;
1005     s = s>>11;
1006     *v = ((u64)s)<<32 | a;
1007     return 7;
1008   }
1009 
1010   /* CSE2 from below */
1011   a &= SLOT_2_0;
1012   p++;
1013   b = b<<14;
1014   b |= *p;
1015   /* b: p3<<28 | p5<<14 | p7 (unmasked) */
1016   if (!(b&0x80))
1017   {
1018     b &= SLOT_4_2_0;
1019     /* moved CSE2 up */
1020     /* a &= (0x7f<<14)|(0x7f); */
1021     a = a<<7;
1022     a |= b;
1023     s = s>>4;
1024     *v = ((u64)s)<<32 | a;
1025     return 8;
1026   }
1027 
1028   p++;
1029   a = a<<15;
1030   a |= *p;
1031   /* a: p4<<29 | p6<<15 | p8 (unmasked) */
1032 
1033   /* moved CSE2 up */
1034   /* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
1035   b &= SLOT_2_0;
1036   b = b<<8;
1037   a |= b;
1038 
1039   s = s<<4;
1040   b = p[-4];
1041   b &= 0x7f;
1042   b = b>>3;
1043   s |= b;
1044 
1045   *v = ((u64)s)<<32 | a;
1046 
1047   return 9;
1048 }
1049 
1050 /*
1051 ** Read a 32-bit variable-length integer from memory starting at p[0].
1052 ** Return the number of bytes read.  The value is stored in *v.
1053 **
1054 ** If the varint stored in p[0] is larger than can fit in a 32-bit unsigned
1055 ** integer, then set *v to 0xffffffff.
1056 **
1057 ** A MACRO version, getVarint32, is provided which inlines the
1058 ** single-byte case.  All code should use the MACRO version as
1059 ** this function assumes the single-byte case has already been handled.
1060 */
1061 u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
1062   u32 a,b;
1063 
1064   /* The 1-byte case.  Overwhelmingly the most common.  Handled inline
1065   ** by the getVarin32() macro */
1066   a = *p;
1067   /* a: p0 (unmasked) */
1068 #ifndef getVarint32
1069   if (!(a&0x80))
1070   {
1071     /* Values between 0 and 127 */
1072     *v = a;
1073     return 1;
1074   }
1075 #endif
1076 
1077   /* The 2-byte case */
1078   p++;
1079   b = *p;
1080   /* b: p1 (unmasked) */
1081   if (!(b&0x80))
1082   {
1083     /* Values between 128 and 16383 */
1084     a &= 0x7f;
1085     a = a<<7;
1086     *v = a | b;
1087     return 2;
1088   }
1089 
1090   /* The 3-byte case */
1091   p++;
1092   a = a<<14;
1093   a |= *p;
1094   /* a: p0<<14 | p2 (unmasked) */
1095   if (!(a&0x80))
1096   {
1097     /* Values between 16384 and 2097151 */
1098     a &= (0x7f<<14)|(0x7f);
1099     b &= 0x7f;
1100     b = b<<7;
1101     *v = a | b;
1102     return 3;
1103   }
1104 
1105   /* A 32-bit varint is used to store size information in btrees.
1106   ** Objects are rarely larger than 2MiB limit of a 3-byte varint.
1107   ** A 3-byte varint is sufficient, for example, to record the size
1108   ** of a 1048569-byte BLOB or string.
1109   **
1110   ** We only unroll the first 1-, 2-, and 3- byte cases.  The very
1111   ** rare larger cases can be handled by the slower 64-bit varint
1112   ** routine.
1113   */
1114 #if 1
1115   {
1116     u64 v64;
1117     u8 n;
1118 
1119     p -= 2;
1120     n = sqlite3GetVarint(p, &v64);
1121     assert( n>3 && n<=9 );
1122     if( (v64 & SQLITE_MAX_U32)!=v64 ){
1123       *v = 0xffffffff;
1124     }else{
1125       *v = (u32)v64;
1126     }
1127     return n;
1128   }
1129 
1130 #else
1131   /* For following code (kept for historical record only) shows an
1132   ** unrolling for the 3- and 4-byte varint cases.  This code is
1133   ** slightly faster, but it is also larger and much harder to test.
1134   */
1135   p++;
1136   b = b<<14;
1137   b |= *p;
1138   /* b: p1<<14 | p3 (unmasked) */
1139   if (!(b&0x80))
1140   {
1141     /* Values between 2097152 and 268435455 */
1142     b &= (0x7f<<14)|(0x7f);
1143     a &= (0x7f<<14)|(0x7f);
1144     a = a<<7;
1145     *v = a | b;
1146     return 4;
1147   }
1148 
1149   p++;
1150   a = a<<14;
1151   a |= *p;
1152   /* a: p0<<28 | p2<<14 | p4 (unmasked) */
1153   if (!(a&0x80))
1154   {
1155     /* Values  between 268435456 and 34359738367 */
1156     a &= SLOT_4_2_0;
1157     b &= SLOT_4_2_0;
1158     b = b<<7;
1159     *v = a | b;
1160     return 5;
1161   }
1162 
1163   /* We can only reach this point when reading a corrupt database
1164   ** file.  In that case we are not in any hurry.  Use the (relatively
1165   ** slow) general-purpose sqlite3GetVarint() routine to extract the
1166   ** value. */
1167   {
1168     u64 v64;
1169     u8 n;
1170 
1171     p -= 4;
1172     n = sqlite3GetVarint(p, &v64);
1173     assert( n>5 && n<=9 );
1174     *v = (u32)v64;
1175     return n;
1176   }
1177 #endif
1178 }
1179 
1180 /*
1181 ** Return the number of bytes that will be needed to store the given
1182 ** 64-bit integer.
1183 */
1184 int sqlite3VarintLen(u64 v){
1185   int i;
1186   for(i=1; (v >>= 7)!=0; i++){ assert( i<10 ); }
1187   return i;
1188 }
1189 
1190 
1191 /*
1192 ** Read or write a four-byte big-endian integer value.
1193 */
1194 u32 sqlite3Get4byte(const u8 *p){
1195 #if SQLITE_BYTEORDER==4321
1196   u32 x;
1197   memcpy(&x,p,4);
1198   return x;
1199 #elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
1200   u32 x;
1201   memcpy(&x,p,4);
1202   return __builtin_bswap32(x);
1203 #elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
1204   u32 x;
1205   memcpy(&x,p,4);
1206   return _byteswap_ulong(x);
1207 #else
1208   testcase( p[0]&0x80 );
1209   return ((unsigned)p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
1210 #endif
1211 }
1212 void sqlite3Put4byte(unsigned char *p, u32 v){
1213 #if SQLITE_BYTEORDER==4321
1214   memcpy(p,&v,4);
1215 #elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
1216   u32 x = __builtin_bswap32(v);
1217   memcpy(p,&x,4);
1218 #elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
1219   u32 x = _byteswap_ulong(v);
1220   memcpy(p,&x,4);
1221 #else
1222   p[0] = (u8)(v>>24);
1223   p[1] = (u8)(v>>16);
1224   p[2] = (u8)(v>>8);
1225   p[3] = (u8)v;
1226 #endif
1227 }
1228 
1229 
1230 
1231 /*
1232 ** Translate a single byte of Hex into an integer.
1233 ** This routine only works if h really is a valid hexadecimal
1234 ** character:  0..9a..fA..F
1235 */
1236 u8 sqlite3HexToInt(int h){
1237   assert( (h>='0' && h<='9') ||  (h>='a' && h<='f') ||  (h>='A' && h<='F') );
1238 #ifdef SQLITE_ASCII
1239   h += 9*(1&(h>>6));
1240 #endif
1241 #ifdef SQLITE_EBCDIC
1242   h += 9*(1&~(h>>4));
1243 #endif
1244   return (u8)(h & 0xf);
1245 }
1246 
1247 #if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC)
1248 /*
1249 ** Convert a BLOB literal of the form "x'hhhhhh'" into its binary
1250 ** value.  Return a pointer to its binary value.  Space to hold the
1251 ** binary value has been obtained from malloc and must be freed by
1252 ** the calling routine.
1253 */
1254 void *sqlite3HexToBlob(sqlite3 *db, const char *z, int n){
1255   char *zBlob;
1256   int i;
1257 
1258   zBlob = (char *)sqlite3DbMallocRawNN(db, n/2 + 1);
1259   n--;
1260   if( zBlob ){
1261     for(i=0; i<n; i+=2){
1262       zBlob[i/2] = (sqlite3HexToInt(z[i])<<4) | sqlite3HexToInt(z[i+1]);
1263     }
1264     zBlob[i/2] = 0;
1265   }
1266   return zBlob;
1267 }
1268 #endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
1269 
1270 /*
1271 ** Log an error that is an API call on a connection pointer that should
1272 ** not have been used.  The "type" of connection pointer is given as the
1273 ** argument.  The zType is a word like "NULL" or "closed" or "invalid".
1274 */
1275 static void logBadConnection(const char *zType){
1276   sqlite3_log(SQLITE_MISUSE,
1277      "API call with %s database connection pointer",
1278      zType
1279   );
1280 }
1281 
1282 /*
1283 ** Check to make sure we have a valid db pointer.  This test is not
1284 ** foolproof but it does provide some measure of protection against
1285 ** misuse of the interface such as passing in db pointers that are
1286 ** NULL or which have been previously closed.  If this routine returns
1287 ** 1 it means that the db pointer is valid and 0 if it should not be
1288 ** dereferenced for any reason.  The calling function should invoke
1289 ** SQLITE_MISUSE immediately.
1290 **
1291 ** sqlite3SafetyCheckOk() requires that the db pointer be valid for
1292 ** use.  sqlite3SafetyCheckSickOrOk() allows a db pointer that failed to
1293 ** open properly and is not fit for general use but which can be
1294 ** used as an argument to sqlite3_errmsg() or sqlite3_close().
1295 */
1296 int sqlite3SafetyCheckOk(sqlite3 *db){
1297   u32 magic;
1298   if( db==0 ){
1299     logBadConnection("NULL");
1300     return 0;
1301   }
1302   magic = db->magic;
1303   if( magic!=SQLITE_MAGIC_OPEN ){
1304     if( sqlite3SafetyCheckSickOrOk(db) ){
1305       testcase( sqlite3GlobalConfig.xLog!=0 );
1306       logBadConnection("unopened");
1307     }
1308     return 0;
1309   }else{
1310     return 1;
1311   }
1312 }
1313 int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
1314   u32 magic;
1315   magic = db->magic;
1316   if( magic!=SQLITE_MAGIC_SICK &&
1317       magic!=SQLITE_MAGIC_OPEN &&
1318       magic!=SQLITE_MAGIC_BUSY ){
1319     testcase( sqlite3GlobalConfig.xLog!=0 );
1320     logBadConnection("invalid");
1321     return 0;
1322   }else{
1323     return 1;
1324   }
1325 }
1326 
1327 /*
1328 ** Attempt to add, substract, or multiply the 64-bit signed value iB against
1329 ** the other 64-bit signed integer at *pA and store the result in *pA.
1330 ** Return 0 on success.  Or if the operation would have resulted in an
1331 ** overflow, leave *pA unchanged and return 1.
1332 */
1333 int sqlite3AddInt64(i64 *pA, i64 iB){
1334 #if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
1335   return __builtin_add_overflow(*pA, iB, pA);
1336 #else
1337   i64 iA = *pA;
1338   testcase( iA==0 ); testcase( iA==1 );
1339   testcase( iB==-1 ); testcase( iB==0 );
1340   if( iB>=0 ){
1341     testcase( iA>0 && LARGEST_INT64 - iA == iB );
1342     testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
1343     if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
1344   }else{
1345     testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
1346     testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
1347     if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
1348   }
1349   *pA += iB;
1350   return 0;
1351 #endif
1352 }
1353 int sqlite3SubInt64(i64 *pA, i64 iB){
1354 #if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
1355   return __builtin_sub_overflow(*pA, iB, pA);
1356 #else
1357   testcase( iB==SMALLEST_INT64+1 );
1358   if( iB==SMALLEST_INT64 ){
1359     testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
1360     if( (*pA)>=0 ) return 1;
1361     *pA -= iB;
1362     return 0;
1363   }else{
1364     return sqlite3AddInt64(pA, -iB);
1365   }
1366 #endif
1367 }
1368 int sqlite3MulInt64(i64 *pA, i64 iB){
1369 #if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
1370   return __builtin_mul_overflow(*pA, iB, pA);
1371 #else
1372   i64 iA = *pA;
1373   if( iB>0 ){
1374     if( iA>LARGEST_INT64/iB ) return 1;
1375     if( iA<SMALLEST_INT64/iB ) return 1;
1376   }else if( iB<0 ){
1377     if( iA>0 ){
1378       if( iB<SMALLEST_INT64/iA ) return 1;
1379     }else if( iA<0 ){
1380       if( iB==SMALLEST_INT64 ) return 1;
1381       if( iA==SMALLEST_INT64 ) return 1;
1382       if( -iA>LARGEST_INT64/-iB ) return 1;
1383     }
1384   }
1385   *pA = iA*iB;
1386   return 0;
1387 #endif
1388 }
1389 
1390 /*
1391 ** Compute the absolute value of a 32-bit signed integer, of possible.  Or
1392 ** if the integer has a value of -2147483648, return +2147483647
1393 */
1394 int sqlite3AbsInt32(int x){
1395   if( x>=0 ) return x;
1396   if( x==(int)0x80000000 ) return 0x7fffffff;
1397   return -x;
1398 }
1399 
1400 #ifdef SQLITE_ENABLE_8_3_NAMES
1401 /*
1402 ** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
1403 ** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
1404 ** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
1405 ** three characters, then shorten the suffix on z[] to be the last three
1406 ** characters of the original suffix.
1407 **
1408 ** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
1409 ** do the suffix shortening regardless of URI parameter.
1410 **
1411 ** Examples:
1412 **
1413 **     test.db-journal    =>   test.nal
1414 **     test.db-wal        =>   test.wal
1415 **     test.db-shm        =>   test.shm
1416 **     test.db-mj7f3319fa =>   test.9fa
1417 */
1418 void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
1419 #if SQLITE_ENABLE_8_3_NAMES<2
1420   if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
1421 #endif
1422   {
1423     int i, sz;
1424     sz = sqlite3Strlen30(z);
1425     for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
1426     if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
1427   }
1428 }
1429 #endif
1430 
1431 /*
1432 ** Find (an approximate) sum of two LogEst values.  This computation is
1433 ** not a simple "+" operator because LogEst is stored as a logarithmic
1434 ** value.
1435 **
1436 */
1437 LogEst sqlite3LogEstAdd(LogEst a, LogEst b){
1438   static const unsigned char x[] = {
1439      10, 10,                         /* 0,1 */
1440       9, 9,                          /* 2,3 */
1441       8, 8,                          /* 4,5 */
1442       7, 7, 7,                       /* 6,7,8 */
1443       6, 6, 6,                       /* 9,10,11 */
1444       5, 5, 5,                       /* 12-14 */
1445       4, 4, 4, 4,                    /* 15-18 */
1446       3, 3, 3, 3, 3, 3,              /* 19-24 */
1447       2, 2, 2, 2, 2, 2, 2,           /* 25-31 */
1448   };
1449   if( a>=b ){
1450     if( a>b+49 ) return a;
1451     if( a>b+31 ) return a+1;
1452     return a+x[a-b];
1453   }else{
1454     if( b>a+49 ) return b;
1455     if( b>a+31 ) return b+1;
1456     return b+x[b-a];
1457   }
1458 }
1459 
1460 /*
1461 ** Convert an integer into a LogEst.  In other words, compute an
1462 ** approximation for 10*log2(x).
1463 */
1464 LogEst sqlite3LogEst(u64 x){
1465   static LogEst a[] = { 0, 2, 3, 5, 6, 7, 8, 9 };
1466   LogEst y = 40;
1467   if( x<8 ){
1468     if( x<2 ) return 0;
1469     while( x<8 ){  y -= 10; x <<= 1; }
1470   }else{
1471 #if GCC_VERSION>=5004000
1472     int i = 60 - __builtin_clzll(x);
1473     y += i*10;
1474     x >>= i;
1475 #else
1476     while( x>255 ){ y += 40; x >>= 4; }  /*OPTIMIZATION-IF-TRUE*/
1477     while( x>15 ){  y += 10; x >>= 1; }
1478 #endif
1479   }
1480   return a[x&7] + y - 10;
1481 }
1482 
1483 #ifndef SQLITE_OMIT_VIRTUALTABLE
1484 /*
1485 ** Convert a double into a LogEst
1486 ** In other words, compute an approximation for 10*log2(x).
1487 */
1488 LogEst sqlite3LogEstFromDouble(double x){
1489   u64 a;
1490   LogEst e;
1491   assert( sizeof(x)==8 && sizeof(a)==8 );
1492   if( x<=1 ) return 0;
1493   if( x<=2000000000 ) return sqlite3LogEst((u64)x);
1494   memcpy(&a, &x, 8);
1495   e = (a>>52) - 1022;
1496   return e*10;
1497 }
1498 #endif /* SQLITE_OMIT_VIRTUALTABLE */
1499 
1500 #if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || \
1501     defined(SQLITE_ENABLE_STAT3_OR_STAT4) || \
1502     defined(SQLITE_EXPLAIN_ESTIMATED_ROWS)
1503 /*
1504 ** Convert a LogEst into an integer.
1505 **
1506 ** Note that this routine is only used when one or more of various
1507 ** non-standard compile-time options is enabled.
1508 */
1509 u64 sqlite3LogEstToInt(LogEst x){
1510   u64 n;
1511   n = x%10;
1512   x /= 10;
1513   if( n>=5 ) n -= 2;
1514   else if( n>=1 ) n -= 1;
1515 #if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || \
1516     defined(SQLITE_EXPLAIN_ESTIMATED_ROWS)
1517   if( x>60 ) return (u64)LARGEST_INT64;
1518 #else
1519   /* If only SQLITE_ENABLE_STAT3_OR_STAT4 is on, then the largest input
1520   ** possible to this routine is 310, resulting in a maximum x of 31 */
1521   assert( x<=60 );
1522 #endif
1523   return x>=3 ? (n+8)<<(x-3) : (n+8)>>(3-x);
1524 }
1525 #endif /* defined SCANSTAT or STAT4 or ESTIMATED_ROWS */
1526 
1527 /*
1528 ** Add a new name/number pair to a VList.  This might require that the
1529 ** VList object be reallocated, so return the new VList.  If an OOM
1530 ** error occurs, the original VList returned and the
1531 ** db->mallocFailed flag is set.
1532 **
1533 ** A VList is really just an array of integers.  To destroy a VList,
1534 ** simply pass it to sqlite3DbFree().
1535 **
1536 ** The first integer is the number of integers allocated for the whole
1537 ** VList.  The second integer is the number of integers actually used.
1538 ** Each name/number pair is encoded by subsequent groups of 3 or more
1539 ** integers.
1540 **
1541 ** Each name/number pair starts with two integers which are the numeric
1542 ** value for the pair and the size of the name/number pair, respectively.
1543 ** The text name overlays one or more following integers.  The text name
1544 ** is always zero-terminated.
1545 **
1546 ** Conceptually:
1547 **
1548 **    struct VList {
1549 **      int nAlloc;   // Number of allocated slots
1550 **      int nUsed;    // Number of used slots
1551 **      struct VListEntry {
1552 **        int iValue;    // Value for this entry
1553 **        int nSlot;     // Slots used by this entry
1554 **        // ... variable name goes here
1555 **      } a[0];
1556 **    }
1557 **
1558 ** During code generation, pointers to the variable names within the
1559 ** VList are taken.  When that happens, nAlloc is set to zero as an
1560 ** indication that the VList may never again be enlarged, since the
1561 ** accompanying realloc() would invalidate the pointers.
1562 */
1563 VList *sqlite3VListAdd(
1564   sqlite3 *db,           /* The database connection used for malloc() */
1565   VList *pIn,            /* The input VList.  Might be NULL */
1566   const char *zName,     /* Name of symbol to add */
1567   int nName,             /* Bytes of text in zName */
1568   int iVal               /* Value to associate with zName */
1569 ){
1570   int nInt;              /* number of sizeof(int) objects needed for zName */
1571   char *z;               /* Pointer to where zName will be stored */
1572   int i;                 /* Index in pIn[] where zName is stored */
1573 
1574   nInt = nName/4 + 3;
1575   assert( pIn==0 || pIn[0]>=3 );  /* Verify ok to add new elements */
1576   if( pIn==0 || pIn[1]+nInt > pIn[0] ){
1577     /* Enlarge the allocation */
1578     sqlite3_int64 nAlloc = (pIn ? 2*(sqlite3_int64)pIn[0] : 10) + nInt;
1579     VList *pOut = sqlite3DbRealloc(db, pIn, nAlloc*sizeof(int));
1580     if( pOut==0 ) return pIn;
1581     if( pIn==0 ) pOut[1] = 2;
1582     pIn = pOut;
1583     pIn[0] = nAlloc;
1584   }
1585   i = pIn[1];
1586   pIn[i] = iVal;
1587   pIn[i+1] = nInt;
1588   z = (char*)&pIn[i+2];
1589   pIn[1] = i+nInt;
1590   assert( pIn[1]<=pIn[0] );
1591   memcpy(z, zName, nName);
1592   z[nName] = 0;
1593   return pIn;
1594 }
1595 
1596 /*
1597 ** Return a pointer to the name of a variable in the given VList that
1598 ** has the value iVal.  Or return a NULL if there is no such variable in
1599 ** the list
1600 */
1601 const char *sqlite3VListNumToName(VList *pIn, int iVal){
1602   int i, mx;
1603   if( pIn==0 ) return 0;
1604   mx = pIn[1];
1605   i = 2;
1606   do{
1607     if( pIn[i]==iVal ) return (char*)&pIn[i+2];
1608     i += pIn[i+1];
1609   }while( i<mx );
1610   return 0;
1611 }
1612 
1613 /*
1614 ** Return the number of the variable named zName, if it is in VList.
1615 ** or return 0 if there is no such variable.
1616 */
1617 int sqlite3VListNameToNum(VList *pIn, const char *zName, int nName){
1618   int i, mx;
1619   if( pIn==0 ) return 0;
1620   mx = pIn[1];
1621   i = 2;
1622   do{
1623     const char *z = (const char*)&pIn[i+2];
1624     if( strncmp(z,zName,nName)==0 && z[nName]==0 ) return pIn[i];
1625     i += pIn[i+1];
1626   }while( i<mx );
1627   return 0;
1628 }
1629