xref: /sqlite-3.40.0/src/util.c (revision 9a243e69)
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 #if HAVE_ISNAN || SQLITE_HAVE_ISNAN
21 # include <math.h>
22 #endif
23 
24 /*
25 ** Routine needed to support the testcase() macro.
26 */
27 #ifdef SQLITE_COVERAGE_TEST
28 void sqlite3Coverage(int x){
29   static unsigned dummy = 0;
30   dummy += (unsigned)x;
31 }
32 #endif
33 
34 /*
35 ** Give a callback to the test harness that can be used to simulate faults
36 ** in places where it is difficult or expensive to do so purely by means
37 ** of inputs.
38 **
39 ** The intent of the integer argument is to let the fault simulator know
40 ** which of multiple sqlite3FaultSim() calls has been hit.
41 **
42 ** Return whatever integer value the test callback returns, or return
43 ** SQLITE_OK if no test callback is installed.
44 */
45 #ifndef SQLITE_UNTESTABLE
46 int sqlite3FaultSim(int iTest){
47   int (*xCallback)(int) = sqlite3GlobalConfig.xTestCallback;
48   return xCallback ? xCallback(iTest) : SQLITE_OK;
49 }
50 #endif
51 
52 #ifndef SQLITE_OMIT_FLOATING_POINT
53 /*
54 ** Return true if the floating point value is Not a Number (NaN).
55 **
56 ** Use the math library isnan() function if compiled with SQLITE_HAVE_ISNAN.
57 ** Otherwise, we have our own implementation that works on most systems.
58 */
59 int sqlite3IsNaN(double x){
60   int rc;   /* The value return */
61 #if !SQLITE_HAVE_ISNAN && !HAVE_ISNAN
62   /*
63   ** Systems that support the isnan() library function should probably
64   ** make use of it by compiling with -DSQLITE_HAVE_ISNAN.  But we have
65   ** found that many systems do not have a working isnan() function so
66   ** this implementation is provided as an alternative.
67   **
68   ** This NaN test sometimes fails if compiled on GCC with -ffast-math.
69   ** On the other hand, the use of -ffast-math comes with the following
70   ** warning:
71   **
72   **      This option [-ffast-math] should never be turned on by any
73   **      -O option since it can result in incorrect output for programs
74   **      which depend on an exact implementation of IEEE or ISO
75   **      rules/specifications for math functions.
76   **
77   ** Under MSVC, this NaN test may fail if compiled with a floating-
78   ** point precision mode other than /fp:precise.  From the MSDN
79   ** documentation:
80   **
81   **      The compiler [with /fp:precise] will properly handle comparisons
82   **      involving NaN. For example, x != x evaluates to true if x is NaN
83   **      ...
84   */
85 #ifdef __FAST_MATH__
86 # error SQLite will not work correctly with the -ffast-math option of GCC.
87 #endif
88   volatile double y = x;
89   volatile double z = y;
90   rc = (y!=z);
91 #else  /* if HAVE_ISNAN */
92   rc = isnan(x);
93 #endif /* HAVE_ISNAN */
94   testcase( rc );
95   return rc;
96 }
97 #endif /* SQLITE_OMIT_FLOATING_POINT */
98 
99 /*
100 ** Compute a string length that is limited to what can be stored in
101 ** lower 30 bits of a 32-bit signed integer.
102 **
103 ** The value returned will never be negative.  Nor will it ever be greater
104 ** than the actual length of the string.  For very long strings (greater
105 ** than 1GiB) the value returned might be less than the true string length.
106 */
107 int sqlite3Strlen30(const char *z){
108   if( z==0 ) return 0;
109   return 0x3fffffff & (int)strlen(z);
110 }
111 
112 /*
113 ** Return the declared type of a column.  Or return zDflt if the column
114 ** has no declared type.
115 **
116 ** The column type is an extra string stored after the zero-terminator on
117 ** the column name if and only if the COLFLAG_HASTYPE flag is set.
118 */
119 char *sqlite3ColumnType(Column *pCol, char *zDflt){
120   if( (pCol->colFlags & COLFLAG_HASTYPE)==0 ) return zDflt;
121   return pCol->zName + strlen(pCol->zName) + 1;
122 }
123 
124 /*
125 ** Helper function for sqlite3Error() - called rarely.  Broken out into
126 ** a separate routine to avoid unnecessary register saves on entry to
127 ** sqlite3Error().
128 */
129 static SQLITE_NOINLINE void  sqlite3ErrorFinish(sqlite3 *db, int err_code){
130   if( db->pErr ) sqlite3ValueSetNull(db->pErr);
131   sqlite3SystemError(db, err_code);
132 }
133 
134 /*
135 ** Set the current error code to err_code and clear any prior error message.
136 ** Also set iSysErrno (by calling sqlite3System) if the err_code indicates
137 ** that would be appropriate.
138 */
139 void sqlite3Error(sqlite3 *db, int err_code){
140   assert( db!=0 );
141   db->errCode = err_code;
142   if( err_code || db->pErr ) sqlite3ErrorFinish(db, err_code);
143 }
144 
145 /*
146 ** Load the sqlite3.iSysErrno field if that is an appropriate thing
147 ** to do based on the SQLite error code in rc.
148 */
149 void sqlite3SystemError(sqlite3 *db, int rc){
150   if( rc==SQLITE_IOERR_NOMEM ) return;
151   rc &= 0xff;
152   if( rc==SQLITE_CANTOPEN || rc==SQLITE_IOERR ){
153     db->iSysErrno = sqlite3OsGetLastError(db->pVfs);
154   }
155 }
156 
157 /*
158 ** Set the most recent error code and error string for the sqlite
159 ** handle "db". The error code is set to "err_code".
160 **
161 ** If it is not NULL, string zFormat specifies the format of the
162 ** error string in the style of the printf functions: The following
163 ** format characters are allowed:
164 **
165 **      %s      Insert a string
166 **      %z      A string that should be freed after use
167 **      %d      Insert an integer
168 **      %T      Insert a token
169 **      %S      Insert the first element of a SrcList
170 **
171 ** zFormat and any string tokens that follow it are assumed to be
172 ** encoded in UTF-8.
173 **
174 ** To clear the most recent error for sqlite handle "db", sqlite3Error
175 ** should be called with err_code set to SQLITE_OK and zFormat set
176 ** to NULL.
177 */
178 void sqlite3ErrorWithMsg(sqlite3 *db, int err_code, const char *zFormat, ...){
179   assert( db!=0 );
180   db->errCode = err_code;
181   sqlite3SystemError(db, err_code);
182   if( zFormat==0 ){
183     sqlite3Error(db, err_code);
184   }else if( db->pErr || (db->pErr = sqlite3ValueNew(db))!=0 ){
185     char *z;
186     va_list ap;
187     va_start(ap, zFormat);
188     z = sqlite3VMPrintf(db, zFormat, ap);
189     va_end(ap);
190     sqlite3ValueSetStr(db->pErr, -1, z, SQLITE_UTF8, SQLITE_DYNAMIC);
191   }
192 }
193 
194 /*
195 ** Add an error message to pParse->zErrMsg and increment pParse->nErr.
196 ** The following formatting characters are allowed:
197 **
198 **      %s      Insert a string
199 **      %z      A string that should be freed after use
200 **      %d      Insert an integer
201 **      %T      Insert a token
202 **      %S      Insert the first element of a SrcList
203 **
204 ** This function should be used to report any error that occurs while
205 ** compiling an SQL statement (i.e. within sqlite3_prepare()). The
206 ** last thing the sqlite3_prepare() function does is copy the error
207 ** stored by this function into the database handle using sqlite3Error().
208 ** Functions sqlite3Error() or sqlite3ErrorWithMsg() should be used
209 ** during statement execution (sqlite3_step() etc.).
210 */
211 void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
212   char *zMsg;
213   va_list ap;
214   sqlite3 *db = pParse->db;
215   va_start(ap, zFormat);
216   zMsg = sqlite3VMPrintf(db, zFormat, ap);
217   va_end(ap);
218   if( db->suppressErr ){
219     sqlite3DbFree(db, zMsg);
220   }else{
221     pParse->nErr++;
222     sqlite3DbFree(db, pParse->zErrMsg);
223     pParse->zErrMsg = zMsg;
224     pParse->rc = SQLITE_ERROR;
225   }
226 }
227 
228 /*
229 ** Convert an SQL-style quoted string into a normal string by removing
230 ** the quote characters.  The conversion is done in-place.  If the
231 ** input does not begin with a quote character, then this routine
232 ** is a no-op.
233 **
234 ** The input string must be zero-terminated.  A new zero-terminator
235 ** is added to the dequoted string.
236 **
237 ** The return value is -1 if no dequoting occurs or the length of the
238 ** dequoted string, exclusive of the zero terminator, if dequoting does
239 ** occur.
240 **
241 ** 2002-Feb-14: This routine is extended to remove MS-Access style
242 ** brackets from around identifiers.  For example:  "[a-b-c]" becomes
243 ** "a-b-c".
244 */
245 void sqlite3Dequote(char *z){
246   char quote;
247   int i, j;
248   if( z==0 ) return;
249   quote = z[0];
250   if( !sqlite3Isquote(quote) ) return;
251   if( quote=='[' ) quote = ']';
252   for(i=1, j=0;; i++){
253     assert( z[i] );
254     if( z[i]==quote ){
255       if( z[i+1]==quote ){
256         z[j++] = quote;
257         i++;
258       }else{
259         break;
260       }
261     }else{
262       z[j++] = z[i];
263     }
264   }
265   z[j] = 0;
266 }
267 
268 /*
269 ** Generate a Token object from a string
270 */
271 void sqlite3TokenInit(Token *p, char *z){
272   p->z = z;
273   p->n = sqlite3Strlen30(z);
274 }
275 
276 /* Convenient short-hand */
277 #define UpperToLower sqlite3UpperToLower
278 
279 /*
280 ** Some systems have stricmp().  Others have strcasecmp().  Because
281 ** there is no consistency, we will define our own.
282 **
283 ** IMPLEMENTATION-OF: R-30243-02494 The sqlite3_stricmp() and
284 ** sqlite3_strnicmp() APIs allow applications and extensions to compare
285 ** the contents of two buffers containing UTF-8 strings in a
286 ** case-independent fashion, using the same definition of "case
287 ** independence" that SQLite uses internally when comparing identifiers.
288 */
289 int sqlite3_stricmp(const char *zLeft, const char *zRight){
290   if( zLeft==0 ){
291     return zRight ? -1 : 0;
292   }else if( zRight==0 ){
293     return 1;
294   }
295   return sqlite3StrICmp(zLeft, zRight);
296 }
297 int sqlite3StrICmp(const char *zLeft, const char *zRight){
298   unsigned char *a, *b;
299   int c;
300   a = (unsigned char *)zLeft;
301   b = (unsigned char *)zRight;
302   for(;;){
303     c = (int)UpperToLower[*a] - (int)UpperToLower[*b];
304     if( c || *a==0 ) break;
305     a++;
306     b++;
307   }
308   return c;
309 }
310 int sqlite3_strnicmp(const char *zLeft, const char *zRight, int N){
311   register unsigned char *a, *b;
312   if( zLeft==0 ){
313     return zRight ? -1 : 0;
314   }else if( zRight==0 ){
315     return 1;
316   }
317   a = (unsigned char *)zLeft;
318   b = (unsigned char *)zRight;
319   while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
320   return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
321 }
322 
323 /*
324 ** The string z[] is an text representation of a real number.
325 ** Convert this string to a double and write it into *pResult.
326 **
327 ** The string z[] is length bytes in length (bytes, not characters) and
328 ** uses the encoding enc.  The string is not necessarily zero-terminated.
329 **
330 ** Return TRUE if the result is a valid real number (or integer) and FALSE
331 ** if the string is empty or contains extraneous text.  Valid numbers
332 ** are in one of these formats:
333 **
334 **    [+-]digits[E[+-]digits]
335 **    [+-]digits.[digits][E[+-]digits]
336 **    [+-].digits[E[+-]digits]
337 **
338 ** Leading and trailing whitespace is ignored for the purpose of determining
339 ** validity.
340 **
341 ** If some prefix of the input string is a valid number, this routine
342 ** returns FALSE but it still converts the prefix and writes the result
343 ** into *pResult.
344 */
345 int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
346 #ifndef SQLITE_OMIT_FLOATING_POINT
347   int incr;
348   const char *zEnd = z + length;
349   /* sign * significand * (10 ^ (esign * exponent)) */
350   int sign = 1;    /* sign of significand */
351   i64 s = 0;       /* significand */
352   int d = 0;       /* adjust exponent for shifting decimal point */
353   int esign = 1;   /* sign of exponent */
354   int e = 0;       /* exponent */
355   int eValid = 1;  /* True exponent is either not used or is well-formed */
356   double result;
357   int nDigits = 0;
358   int nonNum = 0;  /* True if input contains UTF16 with high byte non-zero */
359 
360   assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
361   *pResult = 0.0;   /* Default return value, in case of an error */
362 
363   if( enc==SQLITE_UTF8 ){
364     incr = 1;
365   }else{
366     int i;
367     incr = 2;
368     assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
369     for(i=3-enc; i<length && z[i]==0; i+=2){}
370     nonNum = i<length;
371     zEnd = &z[i^1];
372     z += (enc&1);
373   }
374 
375   /* skip leading spaces */
376   while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
377   if( z>=zEnd ) return 0;
378 
379   /* get sign of significand */
380   if( *z=='-' ){
381     sign = -1;
382     z+=incr;
383   }else if( *z=='+' ){
384     z+=incr;
385   }
386 
387   /* copy max significant digits to significand */
388   while( z<zEnd && sqlite3Isdigit(*z) && s<((LARGEST_INT64-9)/10) ){
389     s = s*10 + (*z - '0');
390     z+=incr, nDigits++;
391   }
392 
393   /* skip non-significant significand digits
394   ** (increase exponent by d to shift decimal left) */
395   while( z<zEnd && sqlite3Isdigit(*z) ) z+=incr, nDigits++, d++;
396   if( z>=zEnd ) goto do_atof_calc;
397 
398   /* if decimal point is present */
399   if( *z=='.' ){
400     z+=incr;
401     /* copy digits from after decimal to significand
402     ** (decrease exponent by d to shift decimal right) */
403     while( z<zEnd && sqlite3Isdigit(*z) ){
404       if( s<((LARGEST_INT64-9)/10) ){
405         s = s*10 + (*z - '0');
406         d--;
407       }
408       z+=incr, nDigits++;
409     }
410   }
411   if( z>=zEnd ) goto do_atof_calc;
412 
413   /* if exponent is present */
414   if( *z=='e' || *z=='E' ){
415     z+=incr;
416     eValid = 0;
417 
418     /* This branch is needed to avoid a (harmless) buffer overread.  The
419     ** special comment alerts the mutation tester that the correct answer
420     ** is obtained even if the branch is omitted */
421     if( z>=zEnd ) goto do_atof_calc;              /*PREVENTS-HARMLESS-OVERREAD*/
422 
423     /* get sign of exponent */
424     if( *z=='-' ){
425       esign = -1;
426       z+=incr;
427     }else if( *z=='+' ){
428       z+=incr;
429     }
430     /* copy digits to exponent */
431     while( z<zEnd && sqlite3Isdigit(*z) ){
432       e = e<10000 ? (e*10 + (*z - '0')) : 10000;
433       z+=incr;
434       eValid = 1;
435     }
436   }
437 
438   /* skip trailing spaces */
439   while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
440 
441 do_atof_calc:
442   /* adjust exponent by d, and update sign */
443   e = (e*esign) + d;
444   if( e<0 ) {
445     esign = -1;
446     e *= -1;
447   } else {
448     esign = 1;
449   }
450 
451   if( s==0 ) {
452     /* In the IEEE 754 standard, zero is signed. */
453     result = sign<0 ? -(double)0 : (double)0;
454   } else {
455     /* Attempt to reduce exponent.
456     **
457     ** Branches that are not required for the correct answer but which only
458     ** help to obtain the correct answer faster are marked with special
459     ** comments, as a hint to the mutation tester.
460     */
461     while( e>0 ){                                       /*OPTIMIZATION-IF-TRUE*/
462       if( esign>0 ){
463         if( s>=(LARGEST_INT64/10) ) break;             /*OPTIMIZATION-IF-FALSE*/
464         s *= 10;
465       }else{
466         if( s%10!=0 ) break;                           /*OPTIMIZATION-IF-FALSE*/
467         s /= 10;
468       }
469       e--;
470     }
471 
472     /* adjust the sign of significand */
473     s = sign<0 ? -s : s;
474 
475     if( e==0 ){                                         /*OPTIMIZATION-IF-TRUE*/
476       result = (double)s;
477     }else{
478       LONGDOUBLE_TYPE scale = 1.0;
479       /* attempt to handle extremely small/large numbers better */
480       if( e>307 ){                                      /*OPTIMIZATION-IF-TRUE*/
481         if( e<342 ){                                    /*OPTIMIZATION-IF-TRUE*/
482           while( e%308 ) { scale *= 1.0e+1; e -= 1; }
483           if( esign<0 ){
484             result = s / scale;
485             result /= 1.0e+308;
486           }else{
487             result = s * scale;
488             result *= 1.0e+308;
489           }
490         }else{ assert( e>=342 );
491           if( esign<0 ){
492             result = 0.0*s;
493           }else{
494 #ifdef INFINITY
495             result = INFINITY*s;
496 #else
497             result = 1e308*1e308*s;  /* Infinity */
498 #endif
499           }
500         }
501       }else{
502         /* 1.0e+22 is the largest power of 10 than can be
503         ** represented exactly. */
504         while( e%22 ) { scale *= 1.0e+1; e -= 1; }
505         while( e>0 ) { scale *= 1.0e+22; e -= 22; }
506         if( esign<0 ){
507           result = s / scale;
508         }else{
509           result = s * scale;
510         }
511       }
512     }
513   }
514 
515   /* store the result */
516   *pResult = result;
517 
518   /* return true if number and no extra non-whitespace chracters after */
519   return z==zEnd && nDigits>0 && eValid && nonNum==0;
520 #else
521   return !sqlite3Atoi64(z, pResult, length, enc);
522 #endif /* SQLITE_OMIT_FLOATING_POINT */
523 }
524 
525 /*
526 ** Compare the 19-character string zNum against the text representation
527 ** value 2^63:  9223372036854775808.  Return negative, zero, or positive
528 ** if zNum is less than, equal to, or greater than the string.
529 ** Note that zNum must contain exactly 19 characters.
530 **
531 ** Unlike memcmp() this routine is guaranteed to return the difference
532 ** in the values of the last digit if the only difference is in the
533 ** last digit.  So, for example,
534 **
535 **      compare2pow63("9223372036854775800", 1)
536 **
537 ** will return -8.
538 */
539 static int compare2pow63(const char *zNum, int incr){
540   int c = 0;
541   int i;
542                     /* 012345678901234567 */
543   const char *pow63 = "922337203685477580";
544   for(i=0; c==0 && i<18; i++){
545     c = (zNum[i*incr]-pow63[i])*10;
546   }
547   if( c==0 ){
548     c = zNum[18*incr] - '8';
549     testcase( c==(-1) );
550     testcase( c==0 );
551     testcase( c==(+1) );
552   }
553   return c;
554 }
555 
556 /*
557 ** Convert zNum to a 64-bit signed integer.  zNum must be decimal. This
558 ** routine does *not* accept hexadecimal notation.
559 **
560 ** If the zNum value is representable as a 64-bit twos-complement
561 ** integer, then write that value into *pNum and return 0.
562 **
563 ** If zNum is exactly 9223372036854775808, return 2.  This special
564 ** case is broken out because while 9223372036854775808 cannot be a
565 ** signed 64-bit integer, its negative -9223372036854775808 can be.
566 **
567 ** If zNum is too big for a 64-bit integer and is not
568 ** 9223372036854775808  or if zNum contains any non-numeric text,
569 ** then return 1.
570 **
571 ** length is the number of bytes in the string (bytes, not characters).
572 ** The string is not necessarily zero-terminated.  The encoding is
573 ** given by enc.
574 */
575 int sqlite3Atoi64(const char *zNum, i64 *pNum, int length, u8 enc){
576   int incr;
577   u64 u = 0;
578   int neg = 0; /* assume positive */
579   int i;
580   int c = 0;
581   int nonNum = 0;  /* True if input contains UTF16 with high byte non-zero */
582   const char *zStart;
583   const char *zEnd = zNum + length;
584   assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
585   if( enc==SQLITE_UTF8 ){
586     incr = 1;
587   }else{
588     incr = 2;
589     assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
590     for(i=3-enc; i<length && zNum[i]==0; i+=2){}
591     nonNum = i<length;
592     zEnd = &zNum[i^1];
593     zNum += (enc&1);
594   }
595   while( zNum<zEnd && sqlite3Isspace(*zNum) ) zNum+=incr;
596   if( zNum<zEnd ){
597     if( *zNum=='-' ){
598       neg = 1;
599       zNum+=incr;
600     }else if( *zNum=='+' ){
601       zNum+=incr;
602     }
603   }
604   zStart = zNum;
605   while( zNum<zEnd && zNum[0]=='0' ){ zNum+=incr; } /* Skip leading zeros. */
606   for(i=0; &zNum[i]<zEnd && (c=zNum[i])>='0' && c<='9'; i+=incr){
607     u = u*10 + c - '0';
608   }
609   if( u>LARGEST_INT64 ){
610     *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
611   }else if( neg ){
612     *pNum = -(i64)u;
613   }else{
614     *pNum = (i64)u;
615   }
616   testcase( i==18 );
617   testcase( i==19 );
618   testcase( i==20 );
619   if( &zNum[i]<zEnd              /* Extra bytes at the end */
620    || (i==0 && zStart==zNum)     /* No digits */
621    || i>19*incr                  /* Too many digits */
622    || nonNum                     /* UTF16 with high-order bytes non-zero */
623   ){
624     /* zNum is empty or contains non-numeric text or is longer
625     ** than 19 digits (thus guaranteeing that it is too large) */
626     return 1;
627   }else if( i<19*incr ){
628     /* Less than 19 digits, so we know that it fits in 64 bits */
629     assert( u<=LARGEST_INT64 );
630     return 0;
631   }else{
632     /* zNum is a 19-digit numbers.  Compare it against 9223372036854775808. */
633     c = compare2pow63(zNum, incr);
634     if( c<0 ){
635       /* zNum is less than 9223372036854775808 so it fits */
636       assert( u<=LARGEST_INT64 );
637       return 0;
638     }else if( c>0 ){
639       /* zNum is greater than 9223372036854775808 so it overflows */
640       return 1;
641     }else{
642       /* zNum is exactly 9223372036854775808.  Fits if negative.  The
643       ** special case 2 overflow if positive */
644       assert( u-1==LARGEST_INT64 );
645       return neg ? 0 : 2;
646     }
647   }
648 }
649 
650 /*
651 ** Transform a UTF-8 integer literal, in either decimal or hexadecimal,
652 ** into a 64-bit signed integer.  This routine accepts hexadecimal literals,
653 ** whereas sqlite3Atoi64() does not.
654 **
655 ** Returns:
656 **
657 **     0    Successful transformation.  Fits in a 64-bit signed integer.
658 **     1    Integer too large for a 64-bit signed integer or is malformed
659 **     2    Special case of 9223372036854775808
660 */
661 int sqlite3DecOrHexToI64(const char *z, i64 *pOut){
662 #ifndef SQLITE_OMIT_HEX_INTEGER
663   if( z[0]=='0'
664    && (z[1]=='x' || z[1]=='X')
665   ){
666     u64 u = 0;
667     int i, k;
668     for(i=2; z[i]=='0'; i++){}
669     for(k=i; sqlite3Isxdigit(z[k]); k++){
670       u = u*16 + sqlite3HexToInt(z[k]);
671     }
672     memcpy(pOut, &u, 8);
673     return (z[k]==0 && k-i<=16) ? 0 : 1;
674   }else
675 #endif /* SQLITE_OMIT_HEX_INTEGER */
676   {
677     return sqlite3Atoi64(z, pOut, sqlite3Strlen30(z), SQLITE_UTF8);
678   }
679 }
680 
681 /*
682 ** If zNum represents an integer that will fit in 32-bits, then set
683 ** *pValue to that integer and return true.  Otherwise return false.
684 **
685 ** This routine accepts both decimal and hexadecimal notation for integers.
686 **
687 ** Any non-numeric characters that following zNum are ignored.
688 ** This is different from sqlite3Atoi64() which requires the
689 ** input number to be zero-terminated.
690 */
691 int sqlite3GetInt32(const char *zNum, int *pValue){
692   sqlite_int64 v = 0;
693   int i, c;
694   int neg = 0;
695   if( zNum[0]=='-' ){
696     neg = 1;
697     zNum++;
698   }else if( zNum[0]=='+' ){
699     zNum++;
700   }
701 #ifndef SQLITE_OMIT_HEX_INTEGER
702   else if( zNum[0]=='0'
703         && (zNum[1]=='x' || zNum[1]=='X')
704         && sqlite3Isxdigit(zNum[2])
705   ){
706     u32 u = 0;
707     zNum += 2;
708     while( zNum[0]=='0' ) zNum++;
709     for(i=0; sqlite3Isxdigit(zNum[i]) && i<8; i++){
710       u = u*16 + sqlite3HexToInt(zNum[i]);
711     }
712     if( (u&0x80000000)==0 && sqlite3Isxdigit(zNum[i])==0 ){
713       memcpy(pValue, &u, 4);
714       return 1;
715     }else{
716       return 0;
717     }
718   }
719 #endif
720   if( !sqlite3Isdigit(zNum[0]) ) return 0;
721   while( zNum[0]=='0' ) zNum++;
722   for(i=0; i<11 && (c = zNum[i] - '0')>=0 && c<=9; i++){
723     v = v*10 + c;
724   }
725 
726   /* The longest decimal representation of a 32 bit integer is 10 digits:
727   **
728   **             1234567890
729   **     2^31 -> 2147483648
730   */
731   testcase( i==10 );
732   if( i>10 ){
733     return 0;
734   }
735   testcase( v-neg==2147483647 );
736   if( v-neg>2147483647 ){
737     return 0;
738   }
739   if( neg ){
740     v = -v;
741   }
742   *pValue = (int)v;
743   return 1;
744 }
745 
746 /*
747 ** Return a 32-bit integer value extracted from a string.  If the
748 ** string is not an integer, just return 0.
749 */
750 int sqlite3Atoi(const char *z){
751   int x = 0;
752   if( z ) sqlite3GetInt32(z, &x);
753   return x;
754 }
755 
756 /*
757 ** The variable-length integer encoding is as follows:
758 **
759 ** KEY:
760 **         A = 0xxxxxxx    7 bits of data and one flag bit
761 **         B = 1xxxxxxx    7 bits of data and one flag bit
762 **         C = xxxxxxxx    8 bits of data
763 **
764 **  7 bits - A
765 ** 14 bits - BA
766 ** 21 bits - BBA
767 ** 28 bits - BBBA
768 ** 35 bits - BBBBA
769 ** 42 bits - BBBBBA
770 ** 49 bits - BBBBBBA
771 ** 56 bits - BBBBBBBA
772 ** 64 bits - BBBBBBBBC
773 */
774 
775 /*
776 ** Write a 64-bit variable-length integer to memory starting at p[0].
777 ** The length of data write will be between 1 and 9 bytes.  The number
778 ** of bytes written is returned.
779 **
780 ** A variable-length integer consists of the lower 7 bits of each byte
781 ** for all bytes that have the 8th bit set and one byte with the 8th
782 ** bit clear.  Except, if we get to the 9th byte, it stores the full
783 ** 8 bits and is the last byte.
784 */
785 static int SQLITE_NOINLINE putVarint64(unsigned char *p, u64 v){
786   int i, j, n;
787   u8 buf[10];
788   if( v & (((u64)0xff000000)<<32) ){
789     p[8] = (u8)v;
790     v >>= 8;
791     for(i=7; i>=0; i--){
792       p[i] = (u8)((v & 0x7f) | 0x80);
793       v >>= 7;
794     }
795     return 9;
796   }
797   n = 0;
798   do{
799     buf[n++] = (u8)((v & 0x7f) | 0x80);
800     v >>= 7;
801   }while( v!=0 );
802   buf[0] &= 0x7f;
803   assert( n<=9 );
804   for(i=0, j=n-1; j>=0; j--, i++){
805     p[i] = buf[j];
806   }
807   return n;
808 }
809 int sqlite3PutVarint(unsigned char *p, u64 v){
810   if( v<=0x7f ){
811     p[0] = v&0x7f;
812     return 1;
813   }
814   if( v<=0x3fff ){
815     p[0] = ((v>>7)&0x7f)|0x80;
816     p[1] = v&0x7f;
817     return 2;
818   }
819   return putVarint64(p,v);
820 }
821 
822 /*
823 ** Bitmasks used by sqlite3GetVarint().  These precomputed constants
824 ** are defined here rather than simply putting the constant expressions
825 ** inline in order to work around bugs in the RVT compiler.
826 **
827 ** SLOT_2_0     A mask for  (0x7f<<14) | 0x7f
828 **
829 ** SLOT_4_2_0   A mask for  (0x7f<<28) | SLOT_2_0
830 */
831 #define SLOT_2_0     0x001fc07f
832 #define SLOT_4_2_0   0xf01fc07f
833 
834 
835 /*
836 ** Read a 64-bit variable-length integer from memory starting at p[0].
837 ** Return the number of bytes read.  The value is stored in *v.
838 */
839 u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
840   u32 a,b,s;
841 
842   a = *p;
843   /* a: p0 (unmasked) */
844   if (!(a&0x80))
845   {
846     *v = a;
847     return 1;
848   }
849 
850   p++;
851   b = *p;
852   /* b: p1 (unmasked) */
853   if (!(b&0x80))
854   {
855     a &= 0x7f;
856     a = a<<7;
857     a |= b;
858     *v = a;
859     return 2;
860   }
861 
862   /* Verify that constants are precomputed correctly */
863   assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
864   assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
865 
866   p++;
867   a = a<<14;
868   a |= *p;
869   /* a: p0<<14 | p2 (unmasked) */
870   if (!(a&0x80))
871   {
872     a &= SLOT_2_0;
873     b &= 0x7f;
874     b = b<<7;
875     a |= b;
876     *v = a;
877     return 3;
878   }
879 
880   /* CSE1 from below */
881   a &= SLOT_2_0;
882   p++;
883   b = b<<14;
884   b |= *p;
885   /* b: p1<<14 | p3 (unmasked) */
886   if (!(b&0x80))
887   {
888     b &= SLOT_2_0;
889     /* moved CSE1 up */
890     /* a &= (0x7f<<14)|(0x7f); */
891     a = a<<7;
892     a |= b;
893     *v = a;
894     return 4;
895   }
896 
897   /* a: p0<<14 | p2 (masked) */
898   /* b: p1<<14 | p3 (unmasked) */
899   /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
900   /* moved CSE1 up */
901   /* a &= (0x7f<<14)|(0x7f); */
902   b &= SLOT_2_0;
903   s = a;
904   /* s: p0<<14 | p2 (masked) */
905 
906   p++;
907   a = a<<14;
908   a |= *p;
909   /* a: p0<<28 | p2<<14 | p4 (unmasked) */
910   if (!(a&0x80))
911   {
912     /* we can skip these cause they were (effectively) done above
913     ** while calculating s */
914     /* a &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
915     /* b &= (0x7f<<14)|(0x7f); */
916     b = b<<7;
917     a |= b;
918     s = s>>18;
919     *v = ((u64)s)<<32 | a;
920     return 5;
921   }
922 
923   /* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
924   s = s<<7;
925   s |= b;
926   /* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
927 
928   p++;
929   b = b<<14;
930   b |= *p;
931   /* b: p1<<28 | p3<<14 | p5 (unmasked) */
932   if (!(b&0x80))
933   {
934     /* we can skip this cause it was (effectively) done above in calc'ing s */
935     /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
936     a &= SLOT_2_0;
937     a = a<<7;
938     a |= b;
939     s = s>>18;
940     *v = ((u64)s)<<32 | a;
941     return 6;
942   }
943 
944   p++;
945   a = a<<14;
946   a |= *p;
947   /* a: p2<<28 | p4<<14 | p6 (unmasked) */
948   if (!(a&0x80))
949   {
950     a &= SLOT_4_2_0;
951     b &= SLOT_2_0;
952     b = b<<7;
953     a |= b;
954     s = s>>11;
955     *v = ((u64)s)<<32 | a;
956     return 7;
957   }
958 
959   /* CSE2 from below */
960   a &= SLOT_2_0;
961   p++;
962   b = b<<14;
963   b |= *p;
964   /* b: p3<<28 | p5<<14 | p7 (unmasked) */
965   if (!(b&0x80))
966   {
967     b &= SLOT_4_2_0;
968     /* moved CSE2 up */
969     /* a &= (0x7f<<14)|(0x7f); */
970     a = a<<7;
971     a |= b;
972     s = s>>4;
973     *v = ((u64)s)<<32 | a;
974     return 8;
975   }
976 
977   p++;
978   a = a<<15;
979   a |= *p;
980   /* a: p4<<29 | p6<<15 | p8 (unmasked) */
981 
982   /* moved CSE2 up */
983   /* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
984   b &= SLOT_2_0;
985   b = b<<8;
986   a |= b;
987 
988   s = s<<4;
989   b = p[-4];
990   b &= 0x7f;
991   b = b>>3;
992   s |= b;
993 
994   *v = ((u64)s)<<32 | a;
995 
996   return 9;
997 }
998 
999 /*
1000 ** Read a 32-bit variable-length integer from memory starting at p[0].
1001 ** Return the number of bytes read.  The value is stored in *v.
1002 **
1003 ** If the varint stored in p[0] is larger than can fit in a 32-bit unsigned
1004 ** integer, then set *v to 0xffffffff.
1005 **
1006 ** A MACRO version, getVarint32, is provided which inlines the
1007 ** single-byte case.  All code should use the MACRO version as
1008 ** this function assumes the single-byte case has already been handled.
1009 */
1010 u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
1011   u32 a,b;
1012 
1013   /* The 1-byte case.  Overwhelmingly the most common.  Handled inline
1014   ** by the getVarin32() macro */
1015   a = *p;
1016   /* a: p0 (unmasked) */
1017 #ifndef getVarint32
1018   if (!(a&0x80))
1019   {
1020     /* Values between 0 and 127 */
1021     *v = a;
1022     return 1;
1023   }
1024 #endif
1025 
1026   /* The 2-byte case */
1027   p++;
1028   b = *p;
1029   /* b: p1 (unmasked) */
1030   if (!(b&0x80))
1031   {
1032     /* Values between 128 and 16383 */
1033     a &= 0x7f;
1034     a = a<<7;
1035     *v = a | b;
1036     return 2;
1037   }
1038 
1039   /* The 3-byte case */
1040   p++;
1041   a = a<<14;
1042   a |= *p;
1043   /* a: p0<<14 | p2 (unmasked) */
1044   if (!(a&0x80))
1045   {
1046     /* Values between 16384 and 2097151 */
1047     a &= (0x7f<<14)|(0x7f);
1048     b &= 0x7f;
1049     b = b<<7;
1050     *v = a | b;
1051     return 3;
1052   }
1053 
1054   /* A 32-bit varint is used to store size information in btrees.
1055   ** Objects are rarely larger than 2MiB limit of a 3-byte varint.
1056   ** A 3-byte varint is sufficient, for example, to record the size
1057   ** of a 1048569-byte BLOB or string.
1058   **
1059   ** We only unroll the first 1-, 2-, and 3- byte cases.  The very
1060   ** rare larger cases can be handled by the slower 64-bit varint
1061   ** routine.
1062   */
1063 #if 1
1064   {
1065     u64 v64;
1066     u8 n;
1067 
1068     p -= 2;
1069     n = sqlite3GetVarint(p, &v64);
1070     assert( n>3 && n<=9 );
1071     if( (v64 & SQLITE_MAX_U32)!=v64 ){
1072       *v = 0xffffffff;
1073     }else{
1074       *v = (u32)v64;
1075     }
1076     return n;
1077   }
1078 
1079 #else
1080   /* For following code (kept for historical record only) shows an
1081   ** unrolling for the 3- and 4-byte varint cases.  This code is
1082   ** slightly faster, but it is also larger and much harder to test.
1083   */
1084   p++;
1085   b = b<<14;
1086   b |= *p;
1087   /* b: p1<<14 | p3 (unmasked) */
1088   if (!(b&0x80))
1089   {
1090     /* Values between 2097152 and 268435455 */
1091     b &= (0x7f<<14)|(0x7f);
1092     a &= (0x7f<<14)|(0x7f);
1093     a = a<<7;
1094     *v = a | b;
1095     return 4;
1096   }
1097 
1098   p++;
1099   a = a<<14;
1100   a |= *p;
1101   /* a: p0<<28 | p2<<14 | p4 (unmasked) */
1102   if (!(a&0x80))
1103   {
1104     /* Values  between 268435456 and 34359738367 */
1105     a &= SLOT_4_2_0;
1106     b &= SLOT_4_2_0;
1107     b = b<<7;
1108     *v = a | b;
1109     return 5;
1110   }
1111 
1112   /* We can only reach this point when reading a corrupt database
1113   ** file.  In that case we are not in any hurry.  Use the (relatively
1114   ** slow) general-purpose sqlite3GetVarint() routine to extract the
1115   ** value. */
1116   {
1117     u64 v64;
1118     u8 n;
1119 
1120     p -= 4;
1121     n = sqlite3GetVarint(p, &v64);
1122     assert( n>5 && n<=9 );
1123     *v = (u32)v64;
1124     return n;
1125   }
1126 #endif
1127 }
1128 
1129 /*
1130 ** Return the number of bytes that will be needed to store the given
1131 ** 64-bit integer.
1132 */
1133 int sqlite3VarintLen(u64 v){
1134   int i;
1135   for(i=1; (v >>= 7)!=0; i++){ assert( i<10 ); }
1136   return i;
1137 }
1138 
1139 
1140 /*
1141 ** Read or write a four-byte big-endian integer value.
1142 */
1143 u32 sqlite3Get4byte(const u8 *p){
1144 #if SQLITE_BYTEORDER==4321
1145   u32 x;
1146   memcpy(&x,p,4);
1147   return x;
1148 #elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
1149   u32 x;
1150   memcpy(&x,p,4);
1151   return __builtin_bswap32(x);
1152 #elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
1153   u32 x;
1154   memcpy(&x,p,4);
1155   return _byteswap_ulong(x);
1156 #else
1157   testcase( p[0]&0x80 );
1158   return ((unsigned)p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
1159 #endif
1160 }
1161 void sqlite3Put4byte(unsigned char *p, u32 v){
1162 #if SQLITE_BYTEORDER==4321
1163   memcpy(p,&v,4);
1164 #elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
1165   u32 x = __builtin_bswap32(v);
1166   memcpy(p,&x,4);
1167 #elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
1168   u32 x = _byteswap_ulong(v);
1169   memcpy(p,&x,4);
1170 #else
1171   p[0] = (u8)(v>>24);
1172   p[1] = (u8)(v>>16);
1173   p[2] = (u8)(v>>8);
1174   p[3] = (u8)v;
1175 #endif
1176 }
1177 
1178 
1179 
1180 /*
1181 ** Translate a single byte of Hex into an integer.
1182 ** This routine only works if h really is a valid hexadecimal
1183 ** character:  0..9a..fA..F
1184 */
1185 u8 sqlite3HexToInt(int h){
1186   assert( (h>='0' && h<='9') ||  (h>='a' && h<='f') ||  (h>='A' && h<='F') );
1187 #ifdef SQLITE_ASCII
1188   h += 9*(1&(h>>6));
1189 #endif
1190 #ifdef SQLITE_EBCDIC
1191   h += 9*(1&~(h>>4));
1192 #endif
1193   return (u8)(h & 0xf);
1194 }
1195 
1196 #if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC)
1197 /*
1198 ** Convert a BLOB literal of the form "x'hhhhhh'" into its binary
1199 ** value.  Return a pointer to its binary value.  Space to hold the
1200 ** binary value has been obtained from malloc and must be freed by
1201 ** the calling routine.
1202 */
1203 void *sqlite3HexToBlob(sqlite3 *db, const char *z, int n){
1204   char *zBlob;
1205   int i;
1206 
1207   zBlob = (char *)sqlite3DbMallocRawNN(db, n/2 + 1);
1208   n--;
1209   if( zBlob ){
1210     for(i=0; i<n; i+=2){
1211       zBlob[i/2] = (sqlite3HexToInt(z[i])<<4) | sqlite3HexToInt(z[i+1]);
1212     }
1213     zBlob[i/2] = 0;
1214   }
1215   return zBlob;
1216 }
1217 #endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
1218 
1219 /*
1220 ** Log an error that is an API call on a connection pointer that should
1221 ** not have been used.  The "type" of connection pointer is given as the
1222 ** argument.  The zType is a word like "NULL" or "closed" or "invalid".
1223 */
1224 static void logBadConnection(const char *zType){
1225   sqlite3_log(SQLITE_MISUSE,
1226      "API call with %s database connection pointer",
1227      zType
1228   );
1229 }
1230 
1231 /*
1232 ** Check to make sure we have a valid db pointer.  This test is not
1233 ** foolproof but it does provide some measure of protection against
1234 ** misuse of the interface such as passing in db pointers that are
1235 ** NULL or which have been previously closed.  If this routine returns
1236 ** 1 it means that the db pointer is valid and 0 if it should not be
1237 ** dereferenced for any reason.  The calling function should invoke
1238 ** SQLITE_MISUSE immediately.
1239 **
1240 ** sqlite3SafetyCheckOk() requires that the db pointer be valid for
1241 ** use.  sqlite3SafetyCheckSickOrOk() allows a db pointer that failed to
1242 ** open properly and is not fit for general use but which can be
1243 ** used as an argument to sqlite3_errmsg() or sqlite3_close().
1244 */
1245 int sqlite3SafetyCheckOk(sqlite3 *db){
1246   u32 magic;
1247   if( db==0 ){
1248     logBadConnection("NULL");
1249     return 0;
1250   }
1251   magic = db->magic;
1252   if( magic!=SQLITE_MAGIC_OPEN ){
1253     if( sqlite3SafetyCheckSickOrOk(db) ){
1254       testcase( sqlite3GlobalConfig.xLog!=0 );
1255       logBadConnection("unopened");
1256     }
1257     return 0;
1258   }else{
1259     return 1;
1260   }
1261 }
1262 int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
1263   u32 magic;
1264   magic = db->magic;
1265   if( magic!=SQLITE_MAGIC_SICK &&
1266       magic!=SQLITE_MAGIC_OPEN &&
1267       magic!=SQLITE_MAGIC_BUSY ){
1268     testcase( sqlite3GlobalConfig.xLog!=0 );
1269     logBadConnection("invalid");
1270     return 0;
1271   }else{
1272     return 1;
1273   }
1274 }
1275 
1276 /*
1277 ** Attempt to add, substract, or multiply the 64-bit signed value iB against
1278 ** the other 64-bit signed integer at *pA and store the result in *pA.
1279 ** Return 0 on success.  Or if the operation would have resulted in an
1280 ** overflow, leave *pA unchanged and return 1.
1281 */
1282 int sqlite3AddInt64(i64 *pA, i64 iB){
1283 #if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
1284   return __builtin_add_overflow(*pA, iB, pA);
1285 #else
1286   i64 iA = *pA;
1287   testcase( iA==0 ); testcase( iA==1 );
1288   testcase( iB==-1 ); testcase( iB==0 );
1289   if( iB>=0 ){
1290     testcase( iA>0 && LARGEST_INT64 - iA == iB );
1291     testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
1292     if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
1293   }else{
1294     testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
1295     testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
1296     if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
1297   }
1298   *pA += iB;
1299   return 0;
1300 #endif
1301 }
1302 int sqlite3SubInt64(i64 *pA, i64 iB){
1303 #if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
1304   return __builtin_sub_overflow(*pA, iB, pA);
1305 #else
1306   testcase( iB==SMALLEST_INT64+1 );
1307   if( iB==SMALLEST_INT64 ){
1308     testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
1309     if( (*pA)>=0 ) return 1;
1310     *pA -= iB;
1311     return 0;
1312   }else{
1313     return sqlite3AddInt64(pA, -iB);
1314   }
1315 #endif
1316 }
1317 int sqlite3MulInt64(i64 *pA, i64 iB){
1318 #if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
1319   return __builtin_mul_overflow(*pA, iB, pA);
1320 #else
1321   i64 iA = *pA;
1322   if( iB>0 ){
1323     if( iA>LARGEST_INT64/iB ) return 1;
1324     if( iA<SMALLEST_INT64/iB ) return 1;
1325   }else if( iB<0 ){
1326     if( iA>0 ){
1327       if( iB<SMALLEST_INT64/iA ) return 1;
1328     }else if( iA<0 ){
1329       if( iB==SMALLEST_INT64 ) return 1;
1330       if( iA==SMALLEST_INT64 ) return 1;
1331       if( -iA>LARGEST_INT64/-iB ) return 1;
1332     }
1333   }
1334   *pA = iA*iB;
1335   return 0;
1336 #endif
1337 }
1338 
1339 /*
1340 ** Compute the absolute value of a 32-bit signed integer, of possible.  Or
1341 ** if the integer has a value of -2147483648, return +2147483647
1342 */
1343 int sqlite3AbsInt32(int x){
1344   if( x>=0 ) return x;
1345   if( x==(int)0x80000000 ) return 0x7fffffff;
1346   return -x;
1347 }
1348 
1349 #ifdef SQLITE_ENABLE_8_3_NAMES
1350 /*
1351 ** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
1352 ** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
1353 ** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
1354 ** three characters, then shorten the suffix on z[] to be the last three
1355 ** characters of the original suffix.
1356 **
1357 ** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
1358 ** do the suffix shortening regardless of URI parameter.
1359 **
1360 ** Examples:
1361 **
1362 **     test.db-journal    =>   test.nal
1363 **     test.db-wal        =>   test.wal
1364 **     test.db-shm        =>   test.shm
1365 **     test.db-mj7f3319fa =>   test.9fa
1366 */
1367 void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
1368 #if SQLITE_ENABLE_8_3_NAMES<2
1369   if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
1370 #endif
1371   {
1372     int i, sz;
1373     sz = sqlite3Strlen30(z);
1374     for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
1375     if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
1376   }
1377 }
1378 #endif
1379 
1380 /*
1381 ** Find (an approximate) sum of two LogEst values.  This computation is
1382 ** not a simple "+" operator because LogEst is stored as a logarithmic
1383 ** value.
1384 **
1385 */
1386 LogEst sqlite3LogEstAdd(LogEst a, LogEst b){
1387   static const unsigned char x[] = {
1388      10, 10,                         /* 0,1 */
1389       9, 9,                          /* 2,3 */
1390       8, 8,                          /* 4,5 */
1391       7, 7, 7,                       /* 6,7,8 */
1392       6, 6, 6,                       /* 9,10,11 */
1393       5, 5, 5,                       /* 12-14 */
1394       4, 4, 4, 4,                    /* 15-18 */
1395       3, 3, 3, 3, 3, 3,              /* 19-24 */
1396       2, 2, 2, 2, 2, 2, 2,           /* 25-31 */
1397   };
1398   if( a>=b ){
1399     if( a>b+49 ) return a;
1400     if( a>b+31 ) return a+1;
1401     return a+x[a-b];
1402   }else{
1403     if( b>a+49 ) return b;
1404     if( b>a+31 ) return b+1;
1405     return b+x[b-a];
1406   }
1407 }
1408 
1409 /*
1410 ** Convert an integer into a LogEst.  In other words, compute an
1411 ** approximation for 10*log2(x).
1412 */
1413 LogEst sqlite3LogEst(u64 x){
1414   static LogEst a[] = { 0, 2, 3, 5, 6, 7, 8, 9 };
1415   LogEst y = 40;
1416   if( x<8 ){
1417     if( x<2 ) return 0;
1418     while( x<8 ){  y -= 10; x <<= 1; }
1419   }else{
1420 #if GCC_VERSION>=5004000
1421     int i = 60 - __builtin_clzll(x);
1422     y += i*10;
1423     x >>= i;
1424 #else
1425     while( x>255 ){ y += 40; x >>= 4; }  /*OPTIMIZATION-IF-TRUE*/
1426     while( x>15 ){  y += 10; x >>= 1; }
1427 #endif
1428   }
1429   return a[x&7] + y - 10;
1430 }
1431 
1432 #ifndef SQLITE_OMIT_VIRTUALTABLE
1433 /*
1434 ** Convert a double into a LogEst
1435 ** In other words, compute an approximation for 10*log2(x).
1436 */
1437 LogEst sqlite3LogEstFromDouble(double x){
1438   u64 a;
1439   LogEst e;
1440   assert( sizeof(x)==8 && sizeof(a)==8 );
1441   if( x<=1 ) return 0;
1442   if( x<=2000000000 ) return sqlite3LogEst((u64)x);
1443   memcpy(&a, &x, 8);
1444   e = (a>>52) - 1022;
1445   return e*10;
1446 }
1447 #endif /* SQLITE_OMIT_VIRTUALTABLE */
1448 
1449 #if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || \
1450     defined(SQLITE_ENABLE_STAT3_OR_STAT4) || \
1451     defined(SQLITE_EXPLAIN_ESTIMATED_ROWS)
1452 /*
1453 ** Convert a LogEst into an integer.
1454 **
1455 ** Note that this routine is only used when one or more of various
1456 ** non-standard compile-time options is enabled.
1457 */
1458 u64 sqlite3LogEstToInt(LogEst x){
1459   u64 n;
1460   n = x%10;
1461   x /= 10;
1462   if( n>=5 ) n -= 2;
1463   else if( n>=1 ) n -= 1;
1464 #if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || \
1465     defined(SQLITE_EXPLAIN_ESTIMATED_ROWS)
1466   if( x>60 ) return (u64)LARGEST_INT64;
1467 #else
1468   /* If only SQLITE_ENABLE_STAT3_OR_STAT4 is on, then the largest input
1469   ** possible to this routine is 310, resulting in a maximum x of 31 */
1470   assert( x<=60 );
1471 #endif
1472   return x>=3 ? (n+8)<<(x-3) : (n+8)>>(3-x);
1473 }
1474 #endif /* defined SCANSTAT or STAT4 or ESTIMATED_ROWS */
1475 
1476 /*
1477 ** Add a new name/number pair to a VList.  This might require that the
1478 ** VList object be reallocated, so return the new VList.  If an OOM
1479 ** error occurs, the original VList returned and the
1480 ** db->mallocFailed flag is set.
1481 **
1482 ** A VList is really just an array of integers.  To destroy a VList,
1483 ** simply pass it to sqlite3DbFree().
1484 **
1485 ** The first integer is the number of integers allocated for the whole
1486 ** VList.  The second integer is the number of integers actually used.
1487 ** Each name/number pair is encoded by subsequent groups of 3 or more
1488 ** integers.
1489 **
1490 ** Each name/number pair starts with two integers which are the numeric
1491 ** value for the pair and the size of the name/number pair, respectively.
1492 ** The text name overlays one or more following integers.  The text name
1493 ** is always zero-terminated.
1494 **
1495 ** Conceptually:
1496 **
1497 **    struct VList {
1498 **      int nAlloc;   // Number of allocated slots
1499 **      int nUsed;    // Number of used slots
1500 **      struct VListEntry {
1501 **        int iValue;    // Value for this entry
1502 **        int nSlot;     // Slots used by this entry
1503 **        // ... variable name goes here
1504 **      } a[0];
1505 **    }
1506 **
1507 ** During code generation, pointers to the variable names within the
1508 ** VList are taken.  When that happens, nAlloc is set to zero as an
1509 ** indication that the VList may never again be enlarged, since the
1510 ** accompanying realloc() would invalidate the pointers.
1511 */
1512 VList *sqlite3VListAdd(
1513   sqlite3 *db,           /* The database connection used for malloc() */
1514   VList *pIn,            /* The input VList.  Might be NULL */
1515   const char *zName,     /* Name of symbol to add */
1516   int nName,             /* Bytes of text in zName */
1517   int iVal               /* Value to associate with zName */
1518 ){
1519   int nInt;              /* number of sizeof(int) objects needed for zName */
1520   char *z;               /* Pointer to where zName will be stored */
1521   int i;                 /* Index in pIn[] where zName is stored */
1522 
1523   nInt = nName/4 + 3;
1524   assert( pIn==0 || pIn[0]>=3 );  /* Verify ok to add new elements */
1525   if( pIn==0 || pIn[1]+nInt > pIn[0] ){
1526     /* Enlarge the allocation */
1527     int nAlloc = (pIn ? pIn[0]*2 : 10) + nInt;
1528     VList *pOut = sqlite3DbRealloc(db, pIn, nAlloc*sizeof(int));
1529     if( pOut==0 ) return pIn;
1530     if( pIn==0 ) pOut[1] = 2;
1531     pIn = pOut;
1532     pIn[0] = nAlloc;
1533   }
1534   i = pIn[1];
1535   pIn[i] = iVal;
1536   pIn[i+1] = nInt;
1537   z = (char*)&pIn[i+2];
1538   pIn[1] = i+nInt;
1539   assert( pIn[1]<=pIn[0] );
1540   memcpy(z, zName, nName);
1541   z[nName] = 0;
1542   return pIn;
1543 }
1544 
1545 /*
1546 ** Return a pointer to the name of a variable in the given VList that
1547 ** has the value iVal.  Or return a NULL if there is no such variable in
1548 ** the list
1549 */
1550 const char *sqlite3VListNumToName(VList *pIn, int iVal){
1551   int i, mx;
1552   if( pIn==0 ) return 0;
1553   mx = pIn[1];
1554   i = 2;
1555   do{
1556     if( pIn[i]==iVal ) return (char*)&pIn[i+2];
1557     i += pIn[i+1];
1558   }while( i<mx );
1559   return 0;
1560 }
1561 
1562 /*
1563 ** Return the number of the variable named zName, if it is in VList.
1564 ** or return 0 if there is no such variable.
1565 */
1566 int sqlite3VListNameToNum(VList *pIn, const char *zName, int nName){
1567   int i, mx;
1568   if( pIn==0 ) return 0;
1569   mx = pIn[1];
1570   i = 2;
1571   do{
1572     const char *z = (const char*)&pIn[i+2];
1573     if( strncmp(z,zName,nName)==0 && z[nName]==0 ) return pIn[i];
1574     i += pIn[i+1];
1575   }while( i<mx );
1576   return 0;
1577 }
1578