xref: /sqlite-3.40.0/src/util.c (revision b0c4ef71)
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     pParse->pWith = 0;
196   }
197 }
198 
199 /*
200 ** If database connection db is currently parsing SQL, then transfer
201 ** error code errCode to that parser if the parser has not already
202 ** encountered some other kind of error.
203 */
204 int sqlite3ErrorToParser(sqlite3 *db, int errCode){
205   Parse *pParse;
206   if( db==0 || (pParse = db->pParse)==0 ) return errCode;
207   pParse->rc = errCode;
208   pParse->nErr++;
209   return errCode;
210 }
211 
212 /*
213 ** Convert an SQL-style quoted string into a normal string by removing
214 ** the quote characters.  The conversion is done in-place.  If the
215 ** input does not begin with a quote character, then this routine
216 ** is a no-op.
217 **
218 ** The input string must be zero-terminated.  A new zero-terminator
219 ** is added to the dequoted string.
220 **
221 ** The return value is -1 if no dequoting occurs or the length of the
222 ** dequoted string, exclusive of the zero terminator, if dequoting does
223 ** occur.
224 **
225 ** 2002-02-14: This routine is extended to remove MS-Access style
226 ** brackets from around identifiers.  For example:  "[a-b-c]" becomes
227 ** "a-b-c".
228 */
229 void sqlite3Dequote(char *z){
230   char quote;
231   int i, j;
232   if( z==0 ) return;
233   quote = z[0];
234   if( !sqlite3Isquote(quote) ) return;
235   if( quote=='[' ) quote = ']';
236   for(i=1, j=0;; i++){
237     assert( z[i] );
238     if( z[i]==quote ){
239       if( z[i+1]==quote ){
240         z[j++] = quote;
241         i++;
242       }else{
243         break;
244       }
245     }else{
246       z[j++] = z[i];
247     }
248   }
249   z[j] = 0;
250 }
251 void sqlite3DequoteExpr(Expr *p){
252   assert( sqlite3Isquote(p->u.zToken[0]) );
253   p->flags |= p->u.zToken[0]=='"' ? EP_Quoted|EP_DblQuoted : EP_Quoted;
254   sqlite3Dequote(p->u.zToken);
255 }
256 
257 /*
258 ** Generate a Token object from a string
259 */
260 void sqlite3TokenInit(Token *p, char *z){
261   p->z = z;
262   p->n = sqlite3Strlen30(z);
263 }
264 
265 /* Convenient short-hand */
266 #define UpperToLower sqlite3UpperToLower
267 
268 /*
269 ** Some systems have stricmp().  Others have strcasecmp().  Because
270 ** there is no consistency, we will define our own.
271 **
272 ** IMPLEMENTATION-OF: R-30243-02494 The sqlite3_stricmp() and
273 ** sqlite3_strnicmp() APIs allow applications and extensions to compare
274 ** the contents of two buffers containing UTF-8 strings in a
275 ** case-independent fashion, using the same definition of "case
276 ** independence" that SQLite uses internally when comparing identifiers.
277 */
278 int sqlite3_stricmp(const char *zLeft, const char *zRight){
279   if( zLeft==0 ){
280     return zRight ? -1 : 0;
281   }else if( zRight==0 ){
282     return 1;
283   }
284   return sqlite3StrICmp(zLeft, zRight);
285 }
286 int sqlite3StrICmp(const char *zLeft, const char *zRight){
287   unsigned char *a, *b;
288   int c, x;
289   a = (unsigned char *)zLeft;
290   b = (unsigned char *)zRight;
291   for(;;){
292     c = *a;
293     x = *b;
294     if( c==x ){
295       if( c==0 ) break;
296     }else{
297       c = (int)UpperToLower[c] - (int)UpperToLower[x];
298       if( c ) break;
299     }
300     a++;
301     b++;
302   }
303   return c;
304 }
305 int sqlite3_strnicmp(const char *zLeft, const char *zRight, int N){
306   register unsigned char *a, *b;
307   if( zLeft==0 ){
308     return zRight ? -1 : 0;
309   }else if( zRight==0 ){
310     return 1;
311   }
312   a = (unsigned char *)zLeft;
313   b = (unsigned char *)zRight;
314   while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
315   return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
316 }
317 
318 /*
319 ** Compute 10 to the E-th power.  Examples:  E==1 results in 10.
320 ** E==2 results in 100.  E==50 results in 1.0e50.
321 **
322 ** This routine only works for values of E between 1 and 341.
323 */
324 static LONGDOUBLE_TYPE sqlite3Pow10(int E){
325 #if defined(_MSC_VER)
326   static const LONGDOUBLE_TYPE x[] = {
327     1.0e+001L,
328     1.0e+002L,
329     1.0e+004L,
330     1.0e+008L,
331     1.0e+016L,
332     1.0e+032L,
333     1.0e+064L,
334     1.0e+128L,
335     1.0e+256L
336   };
337   LONGDOUBLE_TYPE r = 1.0;
338   int i;
339   assert( E>=0 && E<=307 );
340   for(i=0; E!=0; i++, E >>=1){
341     if( E & 1 ) r *= x[i];
342   }
343   return r;
344 #else
345   LONGDOUBLE_TYPE x = 10.0;
346   LONGDOUBLE_TYPE r = 1.0;
347   while(1){
348     if( E & 1 ) r *= x;
349     E >>= 1;
350     if( E==0 ) break;
351     x *= x;
352   }
353   return r;
354 #endif
355 }
356 
357 /*
358 ** The string z[] is an text representation of a real number.
359 ** Convert this string to a double and write it into *pResult.
360 **
361 ** The string z[] is length bytes in length (bytes, not characters) and
362 ** uses the encoding enc.  The string is not necessarily zero-terminated.
363 **
364 ** Return TRUE if the result is a valid real number (or integer) and FALSE
365 ** if the string is empty or contains extraneous text.  More specifically
366 ** return
367 **      1          =>  The input string is a pure integer
368 **      2 or more  =>  The input has a decimal point or eNNN clause
369 **      0 or less  =>  The input string is not a valid number
370 **     -1          =>  Not a valid number, but has a valid prefix which
371 **                     includes a decimal point and/or an eNNN clause
372 **
373 ** Valid numbers are in one of these formats:
374 **
375 **    [+-]digits[E[+-]digits]
376 **    [+-]digits.[digits][E[+-]digits]
377 **    [+-].digits[E[+-]digits]
378 **
379 ** Leading and trailing whitespace is ignored for the purpose of determining
380 ** validity.
381 **
382 ** If some prefix of the input string is a valid number, this routine
383 ** returns FALSE but it still converts the prefix and writes the result
384 ** into *pResult.
385 */
386 #if defined(_MSC_VER)
387 #pragma warning(disable : 4756)
388 #endif
389 int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
390 #ifndef SQLITE_OMIT_FLOATING_POINT
391   int incr;
392   const char *zEnd;
393   /* sign * significand * (10 ^ (esign * exponent)) */
394   int sign = 1;    /* sign of significand */
395   i64 s = 0;       /* significand */
396   int d = 0;       /* adjust exponent for shifting decimal point */
397   int esign = 1;   /* sign of exponent */
398   int e = 0;       /* exponent */
399   int eValid = 1;  /* True exponent is either not used or is well-formed */
400   double result;
401   int nDigit = 0;  /* Number of digits processed */
402   int eType = 1;   /* 1: pure integer,  2+: fractional  -1 or less: bad UTF16 */
403 
404   assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
405   *pResult = 0.0;   /* Default return value, in case of an error */
406   if( length==0 ) return 0;
407 
408   if( enc==SQLITE_UTF8 ){
409     incr = 1;
410     zEnd = z + length;
411   }else{
412     int i;
413     incr = 2;
414     length &= ~1;
415     assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
416     testcase( enc==SQLITE_UTF16LE );
417     testcase( enc==SQLITE_UTF16BE );
418     for(i=3-enc; i<length && z[i]==0; i+=2){}
419     if( i<length ) eType = -100;
420     zEnd = &z[i^1];
421     z += (enc&1);
422   }
423 
424   /* skip leading spaces */
425   while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
426   if( z>=zEnd ) return 0;
427 
428   /* get sign of significand */
429   if( *z=='-' ){
430     sign = -1;
431     z+=incr;
432   }else if( *z=='+' ){
433     z+=incr;
434   }
435 
436   /* copy max significant digits to significand */
437   while( z<zEnd && sqlite3Isdigit(*z) ){
438     s = s*10 + (*z - '0');
439     z+=incr; nDigit++;
440     if( s>=((LARGEST_INT64-9)/10) ){
441       /* skip non-significant significand digits
442       ** (increase exponent by d to shift decimal left) */
443       while( z<zEnd && sqlite3Isdigit(*z) ){ z+=incr; d++; }
444     }
445   }
446   if( z>=zEnd ) goto do_atof_calc;
447 
448   /* if decimal point is present */
449   if( *z=='.' ){
450     z+=incr;
451     eType++;
452     /* copy digits from after decimal to significand
453     ** (decrease exponent by d to shift decimal right) */
454     while( z<zEnd && sqlite3Isdigit(*z) ){
455       if( s<((LARGEST_INT64-9)/10) ){
456         s = s*10 + (*z - '0');
457         d--;
458         nDigit++;
459       }
460       z+=incr;
461     }
462   }
463   if( z>=zEnd ) goto do_atof_calc;
464 
465   /* if exponent is present */
466   if( *z=='e' || *z=='E' ){
467     z+=incr;
468     eValid = 0;
469     eType++;
470 
471     /* This branch is needed to avoid a (harmless) buffer overread.  The
472     ** special comment alerts the mutation tester that the correct answer
473     ** is obtained even if the branch is omitted */
474     if( z>=zEnd ) goto do_atof_calc;              /*PREVENTS-HARMLESS-OVERREAD*/
475 
476     /* get sign of exponent */
477     if( *z=='-' ){
478       esign = -1;
479       z+=incr;
480     }else if( *z=='+' ){
481       z+=incr;
482     }
483     /* copy digits to exponent */
484     while( z<zEnd && sqlite3Isdigit(*z) ){
485       e = e<10000 ? (e*10 + (*z - '0')) : 10000;
486       z+=incr;
487       eValid = 1;
488     }
489   }
490 
491   /* skip trailing spaces */
492   while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
493 
494 do_atof_calc:
495   /* adjust exponent by d, and update sign */
496   e = (e*esign) + d;
497   if( e<0 ) {
498     esign = -1;
499     e *= -1;
500   } else {
501     esign = 1;
502   }
503 
504   if( s==0 ) {
505     /* In the IEEE 754 standard, zero is signed. */
506     result = sign<0 ? -(double)0 : (double)0;
507   } else {
508     /* Attempt to reduce exponent.
509     **
510     ** Branches that are not required for the correct answer but which only
511     ** help to obtain the correct answer faster are marked with special
512     ** comments, as a hint to the mutation tester.
513     */
514     while( e>0 ){                                       /*OPTIMIZATION-IF-TRUE*/
515       if( esign>0 ){
516         if( s>=(LARGEST_INT64/10) ) break;             /*OPTIMIZATION-IF-FALSE*/
517         s *= 10;
518       }else{
519         if( s%10!=0 ) break;                           /*OPTIMIZATION-IF-FALSE*/
520         s /= 10;
521       }
522       e--;
523     }
524 
525     /* adjust the sign of significand */
526     s = sign<0 ? -s : s;
527 
528     if( e==0 ){                                         /*OPTIMIZATION-IF-TRUE*/
529       result = (double)s;
530     }else{
531       /* attempt to handle extremely small/large numbers better */
532       if( e>307 ){                                      /*OPTIMIZATION-IF-TRUE*/
533         if( e<342 ){                                    /*OPTIMIZATION-IF-TRUE*/
534           LONGDOUBLE_TYPE scale = sqlite3Pow10(e-308);
535           if( esign<0 ){
536             result = s / scale;
537             result /= 1.0e+308;
538           }else{
539             result = s * scale;
540             result *= 1.0e+308;
541           }
542         }else{ assert( e>=342 );
543           if( esign<0 ){
544             result = 0.0*s;
545           }else{
546 #ifdef INFINITY
547             result = INFINITY*s;
548 #else
549             result = 1e308*1e308*s;  /* Infinity */
550 #endif
551           }
552         }
553       }else{
554         LONGDOUBLE_TYPE scale = sqlite3Pow10(e);
555         if( esign<0 ){
556           result = s / scale;
557         }else{
558           result = s * scale;
559         }
560       }
561     }
562   }
563 
564   /* store the result */
565   *pResult = result;
566 
567   /* return true if number and no extra non-whitespace chracters after */
568   if( z==zEnd && nDigit>0 && eValid && eType>0 ){
569     return eType;
570   }else if( eType>=2 && (eType==3 || eValid) && nDigit>0 ){
571     return -1;
572   }else{
573     return 0;
574   }
575 #else
576   return !sqlite3Atoi64(z, pResult, length, enc);
577 #endif /* SQLITE_OMIT_FLOATING_POINT */
578 }
579 #if defined(_MSC_VER)
580 #pragma warning(default : 4756)
581 #endif
582 
583 /*
584 ** Compare the 19-character string zNum against the text representation
585 ** value 2^63:  9223372036854775808.  Return negative, zero, or positive
586 ** if zNum is less than, equal to, or greater than the string.
587 ** Note that zNum must contain exactly 19 characters.
588 **
589 ** Unlike memcmp() this routine is guaranteed to return the difference
590 ** in the values of the last digit if the only difference is in the
591 ** last digit.  So, for example,
592 **
593 **      compare2pow63("9223372036854775800", 1)
594 **
595 ** will return -8.
596 */
597 static int compare2pow63(const char *zNum, int incr){
598   int c = 0;
599   int i;
600                     /* 012345678901234567 */
601   const char *pow63 = "922337203685477580";
602   for(i=0; c==0 && i<18; i++){
603     c = (zNum[i*incr]-pow63[i])*10;
604   }
605   if( c==0 ){
606     c = zNum[18*incr] - '8';
607     testcase( c==(-1) );
608     testcase( c==0 );
609     testcase( c==(+1) );
610   }
611   return c;
612 }
613 
614 /*
615 ** Convert zNum to a 64-bit signed integer.  zNum must be decimal. This
616 ** routine does *not* accept hexadecimal notation.
617 **
618 ** Returns:
619 **
620 **    -1    Not even a prefix of the input text looks like an integer
621 **     0    Successful transformation.  Fits in a 64-bit signed integer.
622 **     1    Excess non-space text after the integer value
623 **     2    Integer too large for a 64-bit signed integer or is malformed
624 **     3    Special case of 9223372036854775808
625 **
626 ** length is the number of bytes in the string (bytes, not characters).
627 ** The string is not necessarily zero-terminated.  The encoding is
628 ** given by enc.
629 */
630 int sqlite3Atoi64(const char *zNum, i64 *pNum, int length, u8 enc){
631   int incr;
632   u64 u = 0;
633   int neg = 0; /* assume positive */
634   int i;
635   int c = 0;
636   int nonNum = 0;  /* True if input contains UTF16 with high byte non-zero */
637   int rc;          /* Baseline return code */
638   const char *zStart;
639   const char *zEnd = zNum + length;
640   assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
641   if( enc==SQLITE_UTF8 ){
642     incr = 1;
643   }else{
644     incr = 2;
645     assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
646     for(i=3-enc; i<length && zNum[i]==0; i+=2){}
647     nonNum = i<length;
648     zEnd = &zNum[i^1];
649     zNum += (enc&1);
650   }
651   while( zNum<zEnd && sqlite3Isspace(*zNum) ) zNum+=incr;
652   if( zNum<zEnd ){
653     if( *zNum=='-' ){
654       neg = 1;
655       zNum+=incr;
656     }else if( *zNum=='+' ){
657       zNum+=incr;
658     }
659   }
660   zStart = zNum;
661   while( zNum<zEnd && zNum[0]=='0' ){ zNum+=incr; } /* Skip leading zeros. */
662   for(i=0; &zNum[i]<zEnd && (c=zNum[i])>='0' && c<='9'; i+=incr){
663     u = u*10 + c - '0';
664   }
665   testcase( i==18*incr );
666   testcase( i==19*incr );
667   testcase( i==20*incr );
668   if( u>LARGEST_INT64 ){
669     /* This test and assignment is needed only to suppress UB warnings
670     ** from clang and -fsanitize=undefined.  This test and assignment make
671     ** the code a little larger and slower, and no harm comes from omitting
672     ** them, but we must appaise the undefined-behavior pharisees. */
673     *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
674   }else if( neg ){
675     *pNum = -(i64)u;
676   }else{
677     *pNum = (i64)u;
678   }
679   rc = 0;
680   if( i==0 && zStart==zNum ){    /* No digits */
681     rc = -1;
682   }else if( nonNum ){            /* UTF16 with high-order bytes non-zero */
683     rc = 1;
684   }else if( &zNum[i]<zEnd ){     /* Extra bytes at the end */
685     int jj = i;
686     do{
687       if( !sqlite3Isspace(zNum[jj]) ){
688         rc = 1;          /* Extra non-space text after the integer */
689         break;
690       }
691       jj += incr;
692     }while( &zNum[jj]<zEnd );
693   }
694   if( i<19*incr ){
695     /* Less than 19 digits, so we know that it fits in 64 bits */
696     assert( u<=LARGEST_INT64 );
697     return rc;
698   }else{
699     /* zNum is a 19-digit numbers.  Compare it against 9223372036854775808. */
700     c = i>19*incr ? 1 : compare2pow63(zNum, incr);
701     if( c<0 ){
702       /* zNum is less than 9223372036854775808 so it fits */
703       assert( u<=LARGEST_INT64 );
704       return rc;
705     }else{
706       *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
707       if( c>0 ){
708         /* zNum is greater than 9223372036854775808 so it overflows */
709         return 2;
710       }else{
711         /* zNum is exactly 9223372036854775808.  Fits if negative.  The
712         ** special case 2 overflow if positive */
713         assert( u-1==LARGEST_INT64 );
714         return neg ? rc : 3;
715       }
716     }
717   }
718 }
719 
720 /*
721 ** Transform a UTF-8 integer literal, in either decimal or hexadecimal,
722 ** into a 64-bit signed integer.  This routine accepts hexadecimal literals,
723 ** whereas sqlite3Atoi64() does not.
724 **
725 ** Returns:
726 **
727 **     0    Successful transformation.  Fits in a 64-bit signed integer.
728 **     1    Excess text after the integer value
729 **     2    Integer too large for a 64-bit signed integer or is malformed
730 **     3    Special case of 9223372036854775808
731 */
732 int sqlite3DecOrHexToI64(const char *z, i64 *pOut){
733 #ifndef SQLITE_OMIT_HEX_INTEGER
734   if( z[0]=='0'
735    && (z[1]=='x' || z[1]=='X')
736   ){
737     u64 u = 0;
738     int i, k;
739     for(i=2; z[i]=='0'; i++){}
740     for(k=i; sqlite3Isxdigit(z[k]); k++){
741       u = u*16 + sqlite3HexToInt(z[k]);
742     }
743     memcpy(pOut, &u, 8);
744     return (z[k]==0 && k-i<=16) ? 0 : 2;
745   }else
746 #endif /* SQLITE_OMIT_HEX_INTEGER */
747   {
748     return sqlite3Atoi64(z, pOut, sqlite3Strlen30(z), SQLITE_UTF8);
749   }
750 }
751 
752 /*
753 ** If zNum represents an integer that will fit in 32-bits, then set
754 ** *pValue to that integer and return true.  Otherwise return false.
755 **
756 ** This routine accepts both decimal and hexadecimal notation for integers.
757 **
758 ** Any non-numeric characters that following zNum are ignored.
759 ** This is different from sqlite3Atoi64() which requires the
760 ** input number to be zero-terminated.
761 */
762 int sqlite3GetInt32(const char *zNum, int *pValue){
763   sqlite_int64 v = 0;
764   int i, c;
765   int neg = 0;
766   if( zNum[0]=='-' ){
767     neg = 1;
768     zNum++;
769   }else if( zNum[0]=='+' ){
770     zNum++;
771   }
772 #ifndef SQLITE_OMIT_HEX_INTEGER
773   else if( zNum[0]=='0'
774         && (zNum[1]=='x' || zNum[1]=='X')
775         && sqlite3Isxdigit(zNum[2])
776   ){
777     u32 u = 0;
778     zNum += 2;
779     while( zNum[0]=='0' ) zNum++;
780     for(i=0; sqlite3Isxdigit(zNum[i]) && i<8; i++){
781       u = u*16 + sqlite3HexToInt(zNum[i]);
782     }
783     if( (u&0x80000000)==0 && sqlite3Isxdigit(zNum[i])==0 ){
784       memcpy(pValue, &u, 4);
785       return 1;
786     }else{
787       return 0;
788     }
789   }
790 #endif
791   if( !sqlite3Isdigit(zNum[0]) ) return 0;
792   while( zNum[0]=='0' ) zNum++;
793   for(i=0; i<11 && (c = zNum[i] - '0')>=0 && c<=9; i++){
794     v = v*10 + c;
795   }
796 
797   /* The longest decimal representation of a 32 bit integer is 10 digits:
798   **
799   **             1234567890
800   **     2^31 -> 2147483648
801   */
802   testcase( i==10 );
803   if( i>10 ){
804     return 0;
805   }
806   testcase( v-neg==2147483647 );
807   if( v-neg>2147483647 ){
808     return 0;
809   }
810   if( neg ){
811     v = -v;
812   }
813   *pValue = (int)v;
814   return 1;
815 }
816 
817 /*
818 ** Return a 32-bit integer value extracted from a string.  If the
819 ** string is not an integer, just return 0.
820 */
821 int sqlite3Atoi(const char *z){
822   int x = 0;
823   if( z ) sqlite3GetInt32(z, &x);
824   return x;
825 }
826 
827 /*
828 ** The variable-length integer encoding is as follows:
829 **
830 ** KEY:
831 **         A = 0xxxxxxx    7 bits of data and one flag bit
832 **         B = 1xxxxxxx    7 bits of data and one flag bit
833 **         C = xxxxxxxx    8 bits of data
834 **
835 **  7 bits - A
836 ** 14 bits - BA
837 ** 21 bits - BBA
838 ** 28 bits - BBBA
839 ** 35 bits - BBBBA
840 ** 42 bits - BBBBBA
841 ** 49 bits - BBBBBBA
842 ** 56 bits - BBBBBBBA
843 ** 64 bits - BBBBBBBBC
844 */
845 
846 /*
847 ** Write a 64-bit variable-length integer to memory starting at p[0].
848 ** The length of data write will be between 1 and 9 bytes.  The number
849 ** of bytes written is returned.
850 **
851 ** A variable-length integer consists of the lower 7 bits of each byte
852 ** for all bytes that have the 8th bit set and one byte with the 8th
853 ** bit clear.  Except, if we get to the 9th byte, it stores the full
854 ** 8 bits and is the last byte.
855 */
856 static int SQLITE_NOINLINE putVarint64(unsigned char *p, u64 v){
857   int i, j, n;
858   u8 buf[10];
859   if( v & (((u64)0xff000000)<<32) ){
860     p[8] = (u8)v;
861     v >>= 8;
862     for(i=7; i>=0; i--){
863       p[i] = (u8)((v & 0x7f) | 0x80);
864       v >>= 7;
865     }
866     return 9;
867   }
868   n = 0;
869   do{
870     buf[n++] = (u8)((v & 0x7f) | 0x80);
871     v >>= 7;
872   }while( v!=0 );
873   buf[0] &= 0x7f;
874   assert( n<=9 );
875   for(i=0, j=n-1; j>=0; j--, i++){
876     p[i] = buf[j];
877   }
878   return n;
879 }
880 int sqlite3PutVarint(unsigned char *p, u64 v){
881   if( v<=0x7f ){
882     p[0] = v&0x7f;
883     return 1;
884   }
885   if( v<=0x3fff ){
886     p[0] = ((v>>7)&0x7f)|0x80;
887     p[1] = v&0x7f;
888     return 2;
889   }
890   return putVarint64(p,v);
891 }
892 
893 /*
894 ** Bitmasks used by sqlite3GetVarint().  These precomputed constants
895 ** are defined here rather than simply putting the constant expressions
896 ** inline in order to work around bugs in the RVT compiler.
897 **
898 ** SLOT_2_0     A mask for  (0x7f<<14) | 0x7f
899 **
900 ** SLOT_4_2_0   A mask for  (0x7f<<28) | SLOT_2_0
901 */
902 #define SLOT_2_0     0x001fc07f
903 #define SLOT_4_2_0   0xf01fc07f
904 
905 
906 /*
907 ** Read a 64-bit variable-length integer from memory starting at p[0].
908 ** Return the number of bytes read.  The value is stored in *v.
909 */
910 u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
911   u32 a,b,s;
912 
913   if( ((signed char*)p)[0]>=0 ){
914     *v = *p;
915     return 1;
916   }
917   if( ((signed char*)p)[1]>=0 ){
918     *v = ((u32)(p[0]&0x7f)<<7) | p[1];
919     return 2;
920   }
921 
922   /* Verify that constants are precomputed correctly */
923   assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
924   assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
925 
926   a = ((u32)p[0])<<14;
927   b = p[1];
928   p += 2;
929   a |= *p;
930   /* a: p0<<14 | p2 (unmasked) */
931   if (!(a&0x80))
932   {
933     a &= SLOT_2_0;
934     b &= 0x7f;
935     b = b<<7;
936     a |= b;
937     *v = a;
938     return 3;
939   }
940 
941   /* CSE1 from below */
942   a &= SLOT_2_0;
943   p++;
944   b = b<<14;
945   b |= *p;
946   /* b: p1<<14 | p3 (unmasked) */
947   if (!(b&0x80))
948   {
949     b &= SLOT_2_0;
950     /* moved CSE1 up */
951     /* a &= (0x7f<<14)|(0x7f); */
952     a = a<<7;
953     a |= b;
954     *v = a;
955     return 4;
956   }
957 
958   /* a: p0<<14 | p2 (masked) */
959   /* b: p1<<14 | p3 (unmasked) */
960   /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
961   /* moved CSE1 up */
962   /* a &= (0x7f<<14)|(0x7f); */
963   b &= SLOT_2_0;
964   s = a;
965   /* s: p0<<14 | p2 (masked) */
966 
967   p++;
968   a = a<<14;
969   a |= *p;
970   /* a: p0<<28 | p2<<14 | p4 (unmasked) */
971   if (!(a&0x80))
972   {
973     /* we can skip these cause they were (effectively) done above
974     ** while calculating s */
975     /* a &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
976     /* b &= (0x7f<<14)|(0x7f); */
977     b = b<<7;
978     a |= b;
979     s = s>>18;
980     *v = ((u64)s)<<32 | a;
981     return 5;
982   }
983 
984   /* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
985   s = s<<7;
986   s |= b;
987   /* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
988 
989   p++;
990   b = b<<14;
991   b |= *p;
992   /* b: p1<<28 | p3<<14 | p5 (unmasked) */
993   if (!(b&0x80))
994   {
995     /* we can skip this cause it was (effectively) done above in calc'ing s */
996     /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
997     a &= SLOT_2_0;
998     a = a<<7;
999     a |= b;
1000     s = s>>18;
1001     *v = ((u64)s)<<32 | a;
1002     return 6;
1003   }
1004 
1005   p++;
1006   a = a<<14;
1007   a |= *p;
1008   /* a: p2<<28 | p4<<14 | p6 (unmasked) */
1009   if (!(a&0x80))
1010   {
1011     a &= SLOT_4_2_0;
1012     b &= SLOT_2_0;
1013     b = b<<7;
1014     a |= b;
1015     s = s>>11;
1016     *v = ((u64)s)<<32 | a;
1017     return 7;
1018   }
1019 
1020   /* CSE2 from below */
1021   a &= SLOT_2_0;
1022   p++;
1023   b = b<<14;
1024   b |= *p;
1025   /* b: p3<<28 | p5<<14 | p7 (unmasked) */
1026   if (!(b&0x80))
1027   {
1028     b &= SLOT_4_2_0;
1029     /* moved CSE2 up */
1030     /* a &= (0x7f<<14)|(0x7f); */
1031     a = a<<7;
1032     a |= b;
1033     s = s>>4;
1034     *v = ((u64)s)<<32 | a;
1035     return 8;
1036   }
1037 
1038   p++;
1039   a = a<<15;
1040   a |= *p;
1041   /* a: p4<<29 | p6<<15 | p8 (unmasked) */
1042 
1043   /* moved CSE2 up */
1044   /* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
1045   b &= SLOT_2_0;
1046   b = b<<8;
1047   a |= b;
1048 
1049   s = s<<4;
1050   b = p[-4];
1051   b &= 0x7f;
1052   b = b>>3;
1053   s |= b;
1054 
1055   *v = ((u64)s)<<32 | a;
1056 
1057   return 9;
1058 }
1059 
1060 /*
1061 ** Read a 32-bit variable-length integer from memory starting at p[0].
1062 ** Return the number of bytes read.  The value is stored in *v.
1063 **
1064 ** If the varint stored in p[0] is larger than can fit in a 32-bit unsigned
1065 ** integer, then set *v to 0xffffffff.
1066 **
1067 ** A MACRO version, getVarint32, is provided which inlines the
1068 ** single-byte case.  All code should use the MACRO version as
1069 ** this function assumes the single-byte case has already been handled.
1070 */
1071 u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
1072   u32 a,b;
1073 
1074   /* The 1-byte case.  Overwhelmingly the most common.  Handled inline
1075   ** by the getVarin32() macro */
1076   a = *p;
1077   /* a: p0 (unmasked) */
1078 #ifndef getVarint32
1079   if (!(a&0x80))
1080   {
1081     /* Values between 0 and 127 */
1082     *v = a;
1083     return 1;
1084   }
1085 #endif
1086 
1087   /* The 2-byte case */
1088   p++;
1089   b = *p;
1090   /* b: p1 (unmasked) */
1091   if (!(b&0x80))
1092   {
1093     /* Values between 128 and 16383 */
1094     a &= 0x7f;
1095     a = a<<7;
1096     *v = a | b;
1097     return 2;
1098   }
1099 
1100   /* The 3-byte case */
1101   p++;
1102   a = a<<14;
1103   a |= *p;
1104   /* a: p0<<14 | p2 (unmasked) */
1105   if (!(a&0x80))
1106   {
1107     /* Values between 16384 and 2097151 */
1108     a &= (0x7f<<14)|(0x7f);
1109     b &= 0x7f;
1110     b = b<<7;
1111     *v = a | b;
1112     return 3;
1113   }
1114 
1115   /* A 32-bit varint is used to store size information in btrees.
1116   ** Objects are rarely larger than 2MiB limit of a 3-byte varint.
1117   ** A 3-byte varint is sufficient, for example, to record the size
1118   ** of a 1048569-byte BLOB or string.
1119   **
1120   ** We only unroll the first 1-, 2-, and 3- byte cases.  The very
1121   ** rare larger cases can be handled by the slower 64-bit varint
1122   ** routine.
1123   */
1124 #if 1
1125   {
1126     u64 v64;
1127     u8 n;
1128 
1129     p -= 2;
1130     n = sqlite3GetVarint(p, &v64);
1131     assert( n>3 && n<=9 );
1132     if( (v64 & SQLITE_MAX_U32)!=v64 ){
1133       *v = 0xffffffff;
1134     }else{
1135       *v = (u32)v64;
1136     }
1137     return n;
1138   }
1139 
1140 #else
1141   /* For following code (kept for historical record only) shows an
1142   ** unrolling for the 3- and 4-byte varint cases.  This code is
1143   ** slightly faster, but it is also larger and much harder to test.
1144   */
1145   p++;
1146   b = b<<14;
1147   b |= *p;
1148   /* b: p1<<14 | p3 (unmasked) */
1149   if (!(b&0x80))
1150   {
1151     /* Values between 2097152 and 268435455 */
1152     b &= (0x7f<<14)|(0x7f);
1153     a &= (0x7f<<14)|(0x7f);
1154     a = a<<7;
1155     *v = a | b;
1156     return 4;
1157   }
1158 
1159   p++;
1160   a = a<<14;
1161   a |= *p;
1162   /* a: p0<<28 | p2<<14 | p4 (unmasked) */
1163   if (!(a&0x80))
1164   {
1165     /* Values  between 268435456 and 34359738367 */
1166     a &= SLOT_4_2_0;
1167     b &= SLOT_4_2_0;
1168     b = b<<7;
1169     *v = a | b;
1170     return 5;
1171   }
1172 
1173   /* We can only reach this point when reading a corrupt database
1174   ** file.  In that case we are not in any hurry.  Use the (relatively
1175   ** slow) general-purpose sqlite3GetVarint() routine to extract the
1176   ** value. */
1177   {
1178     u64 v64;
1179     u8 n;
1180 
1181     p -= 4;
1182     n = sqlite3GetVarint(p, &v64);
1183     assert( n>5 && n<=9 );
1184     *v = (u32)v64;
1185     return n;
1186   }
1187 #endif
1188 }
1189 
1190 /*
1191 ** Return the number of bytes that will be needed to store the given
1192 ** 64-bit integer.
1193 */
1194 int sqlite3VarintLen(u64 v){
1195   int i;
1196   for(i=1; (v >>= 7)!=0; i++){ assert( i<10 ); }
1197   return i;
1198 }
1199 
1200 
1201 /*
1202 ** Read or write a four-byte big-endian integer value.
1203 */
1204 u32 sqlite3Get4byte(const u8 *p){
1205 #if SQLITE_BYTEORDER==4321
1206   u32 x;
1207   memcpy(&x,p,4);
1208   return x;
1209 #elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
1210   u32 x;
1211   memcpy(&x,p,4);
1212   return __builtin_bswap32(x);
1213 #elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
1214   u32 x;
1215   memcpy(&x,p,4);
1216   return _byteswap_ulong(x);
1217 #else
1218   testcase( p[0]&0x80 );
1219   return ((unsigned)p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
1220 #endif
1221 }
1222 void sqlite3Put4byte(unsigned char *p, u32 v){
1223 #if SQLITE_BYTEORDER==4321
1224   memcpy(p,&v,4);
1225 #elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
1226   u32 x = __builtin_bswap32(v);
1227   memcpy(p,&x,4);
1228 #elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
1229   u32 x = _byteswap_ulong(v);
1230   memcpy(p,&x,4);
1231 #else
1232   p[0] = (u8)(v>>24);
1233   p[1] = (u8)(v>>16);
1234   p[2] = (u8)(v>>8);
1235   p[3] = (u8)v;
1236 #endif
1237 }
1238 
1239 
1240 
1241 /*
1242 ** Translate a single byte of Hex into an integer.
1243 ** This routine only works if h really is a valid hexadecimal
1244 ** character:  0..9a..fA..F
1245 */
1246 u8 sqlite3HexToInt(int h){
1247   assert( (h>='0' && h<='9') ||  (h>='a' && h<='f') ||  (h>='A' && h<='F') );
1248 #ifdef SQLITE_ASCII
1249   h += 9*(1&(h>>6));
1250 #endif
1251 #ifdef SQLITE_EBCDIC
1252   h += 9*(1&~(h>>4));
1253 #endif
1254   return (u8)(h & 0xf);
1255 }
1256 
1257 #if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC)
1258 /*
1259 ** Convert a BLOB literal of the form "x'hhhhhh'" into its binary
1260 ** value.  Return a pointer to its binary value.  Space to hold the
1261 ** binary value has been obtained from malloc and must be freed by
1262 ** the calling routine.
1263 */
1264 void *sqlite3HexToBlob(sqlite3 *db, const char *z, int n){
1265   char *zBlob;
1266   int i;
1267 
1268   zBlob = (char *)sqlite3DbMallocRawNN(db, n/2 + 1);
1269   n--;
1270   if( zBlob ){
1271     for(i=0; i<n; i+=2){
1272       zBlob[i/2] = (sqlite3HexToInt(z[i])<<4) | sqlite3HexToInt(z[i+1]);
1273     }
1274     zBlob[i/2] = 0;
1275   }
1276   return zBlob;
1277 }
1278 #endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
1279 
1280 /*
1281 ** Log an error that is an API call on a connection pointer that should
1282 ** not have been used.  The "type" of connection pointer is given as the
1283 ** argument.  The zType is a word like "NULL" or "closed" or "invalid".
1284 */
1285 static void logBadConnection(const char *zType){
1286   sqlite3_log(SQLITE_MISUSE,
1287      "API call with %s database connection pointer",
1288      zType
1289   );
1290 }
1291 
1292 /*
1293 ** Check to make sure we have a valid db pointer.  This test is not
1294 ** foolproof but it does provide some measure of protection against
1295 ** misuse of the interface such as passing in db pointers that are
1296 ** NULL or which have been previously closed.  If this routine returns
1297 ** 1 it means that the db pointer is valid and 0 if it should not be
1298 ** dereferenced for any reason.  The calling function should invoke
1299 ** SQLITE_MISUSE immediately.
1300 **
1301 ** sqlite3SafetyCheckOk() requires that the db pointer be valid for
1302 ** use.  sqlite3SafetyCheckSickOrOk() allows a db pointer that failed to
1303 ** open properly and is not fit for general use but which can be
1304 ** used as an argument to sqlite3_errmsg() or sqlite3_close().
1305 */
1306 int sqlite3SafetyCheckOk(sqlite3 *db){
1307   u32 magic;
1308   if( db==0 ){
1309     logBadConnection("NULL");
1310     return 0;
1311   }
1312   magic = db->magic;
1313   if( magic!=SQLITE_MAGIC_OPEN ){
1314     if( sqlite3SafetyCheckSickOrOk(db) ){
1315       testcase( sqlite3GlobalConfig.xLog!=0 );
1316       logBadConnection("unopened");
1317     }
1318     return 0;
1319   }else{
1320     return 1;
1321   }
1322 }
1323 int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
1324   u32 magic;
1325   magic = db->magic;
1326   if( magic!=SQLITE_MAGIC_SICK &&
1327       magic!=SQLITE_MAGIC_OPEN &&
1328       magic!=SQLITE_MAGIC_BUSY ){
1329     testcase( sqlite3GlobalConfig.xLog!=0 );
1330     logBadConnection("invalid");
1331     return 0;
1332   }else{
1333     return 1;
1334   }
1335 }
1336 
1337 /*
1338 ** Attempt to add, substract, or multiply the 64-bit signed value iB against
1339 ** the other 64-bit signed integer at *pA and store the result in *pA.
1340 ** Return 0 on success.  Or if the operation would have resulted in an
1341 ** overflow, leave *pA unchanged and return 1.
1342 */
1343 int sqlite3AddInt64(i64 *pA, i64 iB){
1344 #if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
1345   return __builtin_add_overflow(*pA, iB, pA);
1346 #else
1347   i64 iA = *pA;
1348   testcase( iA==0 ); testcase( iA==1 );
1349   testcase( iB==-1 ); testcase( iB==0 );
1350   if( iB>=0 ){
1351     testcase( iA>0 && LARGEST_INT64 - iA == iB );
1352     testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
1353     if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
1354   }else{
1355     testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
1356     testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
1357     if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
1358   }
1359   *pA += iB;
1360   return 0;
1361 #endif
1362 }
1363 int sqlite3SubInt64(i64 *pA, i64 iB){
1364 #if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
1365   return __builtin_sub_overflow(*pA, iB, pA);
1366 #else
1367   testcase( iB==SMALLEST_INT64+1 );
1368   if( iB==SMALLEST_INT64 ){
1369     testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
1370     if( (*pA)>=0 ) return 1;
1371     *pA -= iB;
1372     return 0;
1373   }else{
1374     return sqlite3AddInt64(pA, -iB);
1375   }
1376 #endif
1377 }
1378 int sqlite3MulInt64(i64 *pA, i64 iB){
1379 #if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
1380   return __builtin_mul_overflow(*pA, iB, pA);
1381 #else
1382   i64 iA = *pA;
1383   if( iB>0 ){
1384     if( iA>LARGEST_INT64/iB ) return 1;
1385     if( iA<SMALLEST_INT64/iB ) return 1;
1386   }else if( iB<0 ){
1387     if( iA>0 ){
1388       if( iB<SMALLEST_INT64/iA ) return 1;
1389     }else if( iA<0 ){
1390       if( iB==SMALLEST_INT64 ) return 1;
1391       if( iA==SMALLEST_INT64 ) return 1;
1392       if( -iA>LARGEST_INT64/-iB ) return 1;
1393     }
1394   }
1395   *pA = iA*iB;
1396   return 0;
1397 #endif
1398 }
1399 
1400 /*
1401 ** Compute the absolute value of a 32-bit signed integer, of possible.  Or
1402 ** if the integer has a value of -2147483648, return +2147483647
1403 */
1404 int sqlite3AbsInt32(int x){
1405   if( x>=0 ) return x;
1406   if( x==(int)0x80000000 ) return 0x7fffffff;
1407   return -x;
1408 }
1409 
1410 #ifdef SQLITE_ENABLE_8_3_NAMES
1411 /*
1412 ** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
1413 ** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
1414 ** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
1415 ** three characters, then shorten the suffix on z[] to be the last three
1416 ** characters of the original suffix.
1417 **
1418 ** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
1419 ** do the suffix shortening regardless of URI parameter.
1420 **
1421 ** Examples:
1422 **
1423 **     test.db-journal    =>   test.nal
1424 **     test.db-wal        =>   test.wal
1425 **     test.db-shm        =>   test.shm
1426 **     test.db-mj7f3319fa =>   test.9fa
1427 */
1428 void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
1429 #if SQLITE_ENABLE_8_3_NAMES<2
1430   if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
1431 #endif
1432   {
1433     int i, sz;
1434     sz = sqlite3Strlen30(z);
1435     for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
1436     if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
1437   }
1438 }
1439 #endif
1440 
1441 /*
1442 ** Find (an approximate) sum of two LogEst values.  This computation is
1443 ** not a simple "+" operator because LogEst is stored as a logarithmic
1444 ** value.
1445 **
1446 */
1447 LogEst sqlite3LogEstAdd(LogEst a, LogEst b){
1448   static const unsigned char x[] = {
1449      10, 10,                         /* 0,1 */
1450       9, 9,                          /* 2,3 */
1451       8, 8,                          /* 4,5 */
1452       7, 7, 7,                       /* 6,7,8 */
1453       6, 6, 6,                       /* 9,10,11 */
1454       5, 5, 5,                       /* 12-14 */
1455       4, 4, 4, 4,                    /* 15-18 */
1456       3, 3, 3, 3, 3, 3,              /* 19-24 */
1457       2, 2, 2, 2, 2, 2, 2,           /* 25-31 */
1458   };
1459   if( a>=b ){
1460     if( a>b+49 ) return a;
1461     if( a>b+31 ) return a+1;
1462     return a+x[a-b];
1463   }else{
1464     if( b>a+49 ) return b;
1465     if( b>a+31 ) return b+1;
1466     return b+x[b-a];
1467   }
1468 }
1469 
1470 /*
1471 ** Convert an integer into a LogEst.  In other words, compute an
1472 ** approximation for 10*log2(x).
1473 */
1474 LogEst sqlite3LogEst(u64 x){
1475   static LogEst a[] = { 0, 2, 3, 5, 6, 7, 8, 9 };
1476   LogEst y = 40;
1477   if( x<8 ){
1478     if( x<2 ) return 0;
1479     while( x<8 ){  y -= 10; x <<= 1; }
1480   }else{
1481 #if GCC_VERSION>=5004000
1482     int i = 60 - __builtin_clzll(x);
1483     y += i*10;
1484     x >>= i;
1485 #else
1486     while( x>255 ){ y += 40; x >>= 4; }  /*OPTIMIZATION-IF-TRUE*/
1487     while( x>15 ){  y += 10; x >>= 1; }
1488 #endif
1489   }
1490   return a[x&7] + y - 10;
1491 }
1492 
1493 #ifndef SQLITE_OMIT_VIRTUALTABLE
1494 /*
1495 ** Convert a double into a LogEst
1496 ** In other words, compute an approximation for 10*log2(x).
1497 */
1498 LogEst sqlite3LogEstFromDouble(double x){
1499   u64 a;
1500   LogEst e;
1501   assert( sizeof(x)==8 && sizeof(a)==8 );
1502   if( x<=1 ) return 0;
1503   if( x<=2000000000 ) return sqlite3LogEst((u64)x);
1504   memcpy(&a, &x, 8);
1505   e = (a>>52) - 1022;
1506   return e*10;
1507 }
1508 #endif /* SQLITE_OMIT_VIRTUALTABLE */
1509 
1510 #if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || \
1511     defined(SQLITE_ENABLE_STAT4) || \
1512     defined(SQLITE_EXPLAIN_ESTIMATED_ROWS)
1513 /*
1514 ** Convert a LogEst into an integer.
1515 **
1516 ** Note that this routine is only used when one or more of various
1517 ** non-standard compile-time options is enabled.
1518 */
1519 u64 sqlite3LogEstToInt(LogEst x){
1520   u64 n;
1521   n = x%10;
1522   x /= 10;
1523   if( n>=5 ) n -= 2;
1524   else if( n>=1 ) n -= 1;
1525 #if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || \
1526     defined(SQLITE_EXPLAIN_ESTIMATED_ROWS)
1527   if( x>60 ) return (u64)LARGEST_INT64;
1528 #else
1529   /* If only SQLITE_ENABLE_STAT4 is on, then the largest input
1530   ** possible to this routine is 310, resulting in a maximum x of 31 */
1531   assert( x<=60 );
1532 #endif
1533   return x>=3 ? (n+8)<<(x-3) : (n+8)>>(3-x);
1534 }
1535 #endif /* defined SCANSTAT or STAT4 or ESTIMATED_ROWS */
1536 
1537 /*
1538 ** Add a new name/number pair to a VList.  This might require that the
1539 ** VList object be reallocated, so return the new VList.  If an OOM
1540 ** error occurs, the original VList returned and the
1541 ** db->mallocFailed flag is set.
1542 **
1543 ** A VList is really just an array of integers.  To destroy a VList,
1544 ** simply pass it to sqlite3DbFree().
1545 **
1546 ** The first integer is the number of integers allocated for the whole
1547 ** VList.  The second integer is the number of integers actually used.
1548 ** Each name/number pair is encoded by subsequent groups of 3 or more
1549 ** integers.
1550 **
1551 ** Each name/number pair starts with two integers which are the numeric
1552 ** value for the pair and the size of the name/number pair, respectively.
1553 ** The text name overlays one or more following integers.  The text name
1554 ** is always zero-terminated.
1555 **
1556 ** Conceptually:
1557 **
1558 **    struct VList {
1559 **      int nAlloc;   // Number of allocated slots
1560 **      int nUsed;    // Number of used slots
1561 **      struct VListEntry {
1562 **        int iValue;    // Value for this entry
1563 **        int nSlot;     // Slots used by this entry
1564 **        // ... variable name goes here
1565 **      } a[0];
1566 **    }
1567 **
1568 ** During code generation, pointers to the variable names within the
1569 ** VList are taken.  When that happens, nAlloc is set to zero as an
1570 ** indication that the VList may never again be enlarged, since the
1571 ** accompanying realloc() would invalidate the pointers.
1572 */
1573 VList *sqlite3VListAdd(
1574   sqlite3 *db,           /* The database connection used for malloc() */
1575   VList *pIn,            /* The input VList.  Might be NULL */
1576   const char *zName,     /* Name of symbol to add */
1577   int nName,             /* Bytes of text in zName */
1578   int iVal               /* Value to associate with zName */
1579 ){
1580   int nInt;              /* number of sizeof(int) objects needed for zName */
1581   char *z;               /* Pointer to where zName will be stored */
1582   int i;                 /* Index in pIn[] where zName is stored */
1583 
1584   nInt = nName/4 + 3;
1585   assert( pIn==0 || pIn[0]>=3 );  /* Verify ok to add new elements */
1586   if( pIn==0 || pIn[1]+nInt > pIn[0] ){
1587     /* Enlarge the allocation */
1588     sqlite3_int64 nAlloc = (pIn ? 2*(sqlite3_int64)pIn[0] : 10) + nInt;
1589     VList *pOut = sqlite3DbRealloc(db, pIn, nAlloc*sizeof(int));
1590     if( pOut==0 ) return pIn;
1591     if( pIn==0 ) pOut[1] = 2;
1592     pIn = pOut;
1593     pIn[0] = nAlloc;
1594   }
1595   i = pIn[1];
1596   pIn[i] = iVal;
1597   pIn[i+1] = nInt;
1598   z = (char*)&pIn[i+2];
1599   pIn[1] = i+nInt;
1600   assert( pIn[1]<=pIn[0] );
1601   memcpy(z, zName, nName);
1602   z[nName] = 0;
1603   return pIn;
1604 }
1605 
1606 /*
1607 ** Return a pointer to the name of a variable in the given VList that
1608 ** has the value iVal.  Or return a NULL if there is no such variable in
1609 ** the list
1610 */
1611 const char *sqlite3VListNumToName(VList *pIn, int iVal){
1612   int i, mx;
1613   if( pIn==0 ) return 0;
1614   mx = pIn[1];
1615   i = 2;
1616   do{
1617     if( pIn[i]==iVal ) return (char*)&pIn[i+2];
1618     i += pIn[i+1];
1619   }while( i<mx );
1620   return 0;
1621 }
1622 
1623 /*
1624 ** Return the number of the variable named zName, if it is in VList.
1625 ** or return 0 if there is no such variable.
1626 */
1627 int sqlite3VListNameToNum(VList *pIn, const char *zName, int nName){
1628   int i, mx;
1629   if( pIn==0 ) return 0;
1630   mx = pIn[1];
1631   i = 2;
1632   do{
1633     const char *z = (const char*)&pIn[i+2];
1634     if( strncmp(z,zName,nName)==0 && z[nName]==0 ) return pIn[i];
1635     i += pIn[i+1];
1636   }while( i<mx );
1637   return 0;
1638 }
1639