SQLite

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.80 2004/08/08 20:22:18 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "vdbeInt.h"

  int arg,
  sqlite3_value **argv
){
  sqlite *db = sqlite3_user_data(context);
  sqlite3_result_int(context, sqlite3_total_changes(db));
}

#if 0

/*
** A LIKE pattern compiles to an instance of the following structure. Refer
** to the comment for compileLike() function for details.
*/
struct LikePattern {
  int nState;
  struct LikeState {
    int val;           /* Unicode codepoint or -1 for any char i.e. '_' */
    int failstate;     /* State to jump to if next char is not val */
  } aState[1];

};
typedef struct LikePattern LikePattern;

void deleteLike(void *pLike){
  sqliteFree(pLike);
}
/* #define TRACE_LIKE */
#if defined(TRACE_LIKE) && !defined(NDEBUG)
char *dumpLike(LikePattern *pLike){
  int i;
  int k = 0;
  char *zBuf = (char *)sqliteMalloc(pLike->nState*40);
  
  k += sprintf(&zBuf[k], "%d states - ", pLike->nState);
  for(i=0; i<pLike->nState; i++){
    k += sprintf(&zBuf[k], " %d:(%d, %d)", i, pLike->aState[i].val,
        pLike->aState[i].failstate);
  }
  return zBuf;
}
#endif

/*
** This function compiles an SQL 'LIKE' pattern into a state machine, 
** represented by a LikePattern structure.
**
** Each state of the state-machine has two attributes, 'val' and
** 'failstate'. The val attribute is either the value of a unicode 
** codepoint, or -1, indicating a '_' wildcard (match any single
** character). The failstate is either the number of another state
** or -1, indicating jump to 'no match'.
**
** To see if a string matches a pattern the pattern is
** compiled to a state machine that is executed according to the algorithm
** below. The string is assumed to be terminated by a 'NUL' character
** (unicode codepoint 0).
**
** 1   S = 0
** 2   DO 
** 3       C = <Next character from input string>
** 4       IF( C matches <State S val> )
** 5           S = S+1
** 6       ELSE IF( S != <State S failstate> )
** 7           S = <State S failstate>
** 8           <Rewind Input string 1 character>
** 9   WHILE( (C != NUL) AND (S != FAILED) )
** 10
** 11  IF( S == <number of states> )
** 12      RETURN MATCH
** 13  ELSE
** 14      RETURN NO-MATCH
**       
** In practice there is a small optimization to avoid the <Rewind>
** operation in line 8 of the description above.
**
** For example, the following pattern, 'X%ABabc%_Y' is compiled to
** the state machine below.
**
** State    Val          FailState
** -------------------------------
** 0        120 (x)      -1 (NO MATCH)
** 1        97  (a)      1
** 2        98  (b)      1
** 3        97  (a)      1
** 4        98  (b)      2
** 5        99  (c)      3
** 6        -1  (_)      6
** 7        121 (y)      7
** 8        0   (NUL)    7
**
** The algorithms implemented to compile and execute the state machine were
** first presented in "Fast pattern matching in strings", Knuth, Morris and
** Pratt, 1977.
**       
*/

LikePattern *compileLike(sqlite3_value *pPattern, u8 enc){
  LikePattern *pLike;
  struct LikeState *aState;
  int pc_state = -1;    /* State number of previous '%' wild card */
  int n = 0;
  int c;






  int offset = 0;

  const char *zLike;
 
  if( enc==SQLITE_UTF8 ){
    zLike = sqlite3_value_text(pPattern);
    n = sqlite3_value_bytes(pPattern) + 1;
  }else{
    zLike = sqlite3_value_text16(pPattern);
    n = sqlite3_value_bytes16(pPattern)/2 + 1;
  }

  pLike = (LikePattern *)
      sqliteMalloc(sizeof(LikePattern)+n*sizeof(struct LikeState));
  aState = pLike->aState;

  n = 0;
  do {
    c = sqlite3ReadUniChar(zLike, &offset, &enc, 1);
    if( c==95 ){        /* A '_' wildcard */
      aState[n].val = -1;
      n++;
    }else if( c==37 ){  /* A '%' wildcard */
      aState[n].failstate = n;
      pc_state = n;
    }else{              /* A regular character */
      aState[n].val = c;

      assert( pc_state<=n );
      if( pc_state<0 ){
        aState[n].failstate = -1;
      }else if( pc_state==n ){
        if( c ){
          aState[n].failstate = pc_state;
        }else{
          aState[n].failstate = -2;
        }
      }else{
        int k = pLike->aState[n-1].failstate;
        while( k>pc_state && aState[k+1].val!=-1 && aState[k+1].val!=c ){
          k = aState[k].failstate;
        }
        if( k!=pc_state && aState[k+1].val==c ){
          assert( k==pc_state );
          k++;
        }
        aState[n].failstate = k;
      }
      n++;
    }
  }while( c );
  pLike->nState = n;
#if defined(TRACE_LIKE) && !defined(NDEBUG)
  {
    char *zCompiled = dumpLike(pLike);
    printf("Pattern=\"%s\" Compiled=\"%s\"\n", zPattern, zCompiled);
    sqliteFree(zCompiled);
  }
#endif
  return pLike;
}

/*
** Implementation of the like() SQL function.  This function implements
** the build-in LIKE operator.  The first argument to the function is the
** pattern and the second argument is the string.  So, the SQL statements:





**
**       A LIKE B

**
** is implemented as like(B,A).

**
** If the pointer retrieved by via a call to sqlite3_user_data() is
** not NULL, then this function uses UTF-16. Otherwise UTF-8.

*/
static void likeFunc(
  sqlite3_context *context, 
  int argc, 
  sqlite3_value **argv



){
  register int c;

  u8 enc;
  int offset = 0;
  const unsigned char *zString;
  LikePattern *pLike = sqlite3_get_auxdata(context, 0); 
  struct LikeState *aState;
  register struct LikeState *pState;


  /* If either argument is NULL, the result is NULL */
  if( sqlite3_value_type(argv[1])==SQLITE_NULL || 
      sqlite3_value_type(argv[0])==SQLITE_NULL ){


    return;

  }


  /* If the user-data pointer is NULL, use UTF-8. Otherwise UTF-16. */

  if( sqlite3_user_data(context) ){
    enc = SQLITE_UTF16NATIVE;
    zString = (const unsigned char *)sqlite3_value_text16(argv[1]);
    assert(0);
  }else{
    enc = SQLITE_UTF8;
    zString = sqlite3_value_text(argv[1]);
  }










  /* If the LIKE pattern has not been compiled, compile it now. */
  if( !pLike ){
    pLike = compileLike(argv[0], enc);
    if( !pLike ){
      sqlite3_result_error(context, "out of memory", -1);
      return;
    }
    sqlite3_set_auxdata(context, 0, pLike, deleteLike);

  }
  aState = pLike->aState;



  pState = aState;

  do {
    if( enc==SQLITE_UTF8 ){

      c = zString[offset++];



      if( c&0x80 ){
        offset--;
        c = sqlite3ReadUniChar(zString, &offset, &enc, 1);

      }
    }else{
      c = sqlite3ReadUniChar(zString, &offset, &enc, 1);
    }

skip_read:

#if defined(TRACE_LIKE) && !defined(NDEBUG)

    printf("State=%d:(%d, %d) Input=%d\n", 
        (aState - pState), pState->val, pState->failstate, c);

#endif

    if( pState->val==-1 || pState->val==c ){
      pState++;
    }else{
      struct LikeState *pFailState = &aState[pState->failstate];
      if( pState!=pFailState ){
        pState = pFailState;
        if( c && pState>=aState ) goto skip_read;
      }

    }


  }while( c && pState>=aState );

  if( (pState-aState)==pLike->nState || (pState-aState)<-1 ){
    sqlite3_result_int(context, 1);
  }else{


    sqlite3_result_int(context, 0);

  }
}


#endif

/*
** Implementation of the like() SQL function.  This function implements
** the build-in LIKE operator.  The first argument to the function is the
** pattern and the second argument is the string.  So, the SQL statements:
**
**       A LIKE B

  sqlite3_context *context, 
  int argc, 
  sqlite3_value **argv
){
  const unsigned char *zA = sqlite3_value_text(argv[0]);
  const unsigned char *zB = sqlite3_value_text(argv[1]);
  if( zA && zB ){
    sqlite3_result_int(context, sqlite3utf8LikeCompare(zA, zB));
  }
}

/*
** Implementation of the glob() SQL function.  This function implements
** the build-in GLOB operator.  The first argument to the function is the
** string and the second argument is the pattern.  So, the SQL statements:
**
**       A GLOB B
**
** is implemented as glob(A,B).
*/
static void globFunc(sqlite3_context *context, int arg, sqlite3_value **argv){
  const unsigned char *zA = sqlite3_value_text(argv[0]);
  const unsigned char *zB = sqlite3_value_text(argv[1]);
  if( zA && zB ){
    sqlite3_result_int(context, sqlite3GlobCompare(zA, zB));
  }
}

/*
** Implementation of the NULLIF(x,y) function.  The result is the first
** argument if the arguments are different.  The result is NULL if the
** arguments are equal to each other.

  sqlite3_value *pRes;
  pRes = (sqlite3_value *)sqlite3_aggregate_context(context, sizeof(Mem));
  if( pRes->flags ){
    sqlite3_result_value(context, pRes);
  }
  sqlite3VdbeMemRelease(pRes);
}


/*
** This function registered all of the above C functions as SQL
** functions.  This should be the only routine in this file with
** external linkage.
*/
void sqlite3RegisterBuiltinFunctions(sqlite *db){

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.316 2004/08/21 17:54:45 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

#include "config.h"
#include "sqlite3.h"
#include "hash.h"

Table *sqlite3LocateTable(Parse*,const char*, const char*);
Index *sqlite3FindIndex(sqlite*,const char*, const char*);
void sqlite3UnlinkAndDeleteTable(sqlite*,int,const char*);
void sqlite3UnlinkAndDeleteIndex(sqlite*,int,const char*);
void sqlite3UnlinkAndDeleteTrigger(sqlite*,int,const char*);
void sqlite3Vacuum(Parse*, Token*);
int sqlite3RunVacuum(char**, sqlite*);
int sqlite3GlobCompare(const unsigned char*,const unsigned char*);
char *sqlite3NameFromToken(Token*);
int sqlite3ExprCheck(Parse*, Expr*, int, int*);
int sqlite3ExprCompare(Expr*, Expr*);
int sqliteFuncId(Token*);
int sqlite3ExprResolveIds(Parse*, SrcList*, ExprList*, Expr*);
int sqlite3ExprResolveAndCheck(Parse*,SrcList*,ExprList*,Expr*,int,int*);
int sqlite3ExprAnalyzeAggregates(Parse*, Expr*);

int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);
double sqlite3AtoF(const char *z, const char **);
char *sqlite3_snprintf(int,char*,const char*,...);
int sqlite3GetInt32(const char *, int*);
int sqlite3FitsIn64Bits(const char *);
int sqlite3utf16ByteLen(const void *pData, int nChar);
int sqlite3utf8CharLen(const char *pData, int nByte);
int sqlite3utf8LikeCompare(const unsigned char*, const unsigned char*);
int sqlite3PutVarint(unsigned char *, u64);
int sqlite3GetVarint(const unsigned char *, u64 *);
int sqlite3GetVarint32(const unsigned char *, u32 *);
int sqlite3VarintLen(u64 v);
char sqlite3AffinityType(const char *, int);
void sqlite3IndexAffinityStr(Vdbe *, Index *);
void sqlite3TableAffinityStr(Vdbe *, Table *);

const void *sqlite3ValueText(sqlite3_value*, u8);
int sqlite3ValueBytes(sqlite3_value*, u8);
void sqlite3ValueSetStr(sqlite3_value*, int, const void *,u8, void(*)(void*));
void sqlite3ValueFree(sqlite3_value*);
sqlite3_value *sqlite3ValueNew();
sqlite3_value *sqlite3GetTransientValue(sqlite *db);


#endif

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used to translate between UTF-8, 
** UTF-16, UTF-16BE, and UTF-16LE.
**
** $Id: utf.c,v 1.27 2004/08/08 23:39:19 drh Exp $
**
** Notes on UTF-8:
**
**   Byte-0    Byte-1    Byte-2    Byte-3    Value
**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx

** sqlite3utf8LikeCompare()  - Do a LIKE match given two UTF8 char* strings.
**
*/
#include <assert.h>
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** The following macro, LOWERCASE(x), takes an integer representing a
** unicode code point. The value returned is the same code point folded to
** lower case, if applicable. SQLite currently understands the upper/lower
** case relationship between the 26 characters used in the English
** language only.
**
** This means that characters with umlauts etc. will not be folded
** correctly (unless they are encoded as composite characters, which would
** doubtless cause much trouble).
*/
#define LOWERCASE(x) (x<91?(int)(UpperToLower[x]):x)
static unsigned char UpperToLower[91] = {
      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17,
     18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
     36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
     54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 97, 98, 99,100,101,102,103,
    104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,
    122,
};

/*
** This table maps from the first byte of a UTF-8 character to the number
** of trailing bytes expected. A value '255' indicates that the table key
** is not a legal first byte for a UTF-8 character.
*/
static const u8 xtra_utf8_bytes[256]  = {
/* 0xxxxxxx */

  switch( xtra ){                                      \
    case 255: c = (int)0xFFFD; break;                  \
    case 3: c = (c<<6) + *(zIn)++;                     \
    case 2: c = (c<<6) + *(zIn)++;                     \
    case 1: c = (c<<6) + *(zIn)++;                     \
    c -= xtra_utf8_bits[xtra];                         \
  }                                                    \





}

#define SKIP_UTF8(zIn) {                               \
  zIn += (xtra_utf8_bytes[*(u8 *)zIn] + 1);            \
}

#define WRITE_UTF8(zOut, c) {                          \

      READ_UTF16LE(z, c);
      n++;
    }
  }
  return (z-(char const *)zIn)-((c==0)?2:0);
}

/*
** Compare two UTF-8 strings for equality using the "LIKE" operator of
** SQL.  The '%' character matches any sequence of 0 or more
** characters and '_' matches any single character.  Case is
** not significant.
*/
int sqlite3utf8LikeCompare(
  const unsigned char *zPattern, 
  const unsigned char *zString
){
  register int c;
  int c2;

  while( (c = LOWERCASE(*zPattern))!=0 ){
    switch( c ){
      case '%': {
        while( (c=zPattern[1]) == '%' || c == '_' ){
          if( c=='_' ){
            if( *zString==0 ) return 0;
            SKIP_UTF8(zString);
          }
          zPattern++;
        }
        if( c==0 ) return 1;
        c = LOWERCASE(c);
        while( (c2=LOWERCASE(*zString))!=0 ){
          while( c2 != 0 && c2 != c ){ 
            zString++;
            c2 = LOWERCASE(*zString); 
          }
          if( c2==0 ) return 0;
          if( sqlite3utf8LikeCompare(&zPattern[1],zString) ) return 1;
          SKIP_UTF8(zString);
        }
        return 0;
      }
      case '_': {
        if( *zString==0 ) return 0;
        SKIP_UTF8(zString);
        zPattern++;
        break;
      }
      default: {
        if( c != LOWERCASE(*zString) ) return 0;
        zPattern++;
        zString++;
        break;
      }
    }
  }
  return *zString==0;
}

/*
** UTF-16 implementation of the substr()
*/
void sqlite3utf16Substr(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.113 2004/08/18 02:10:15 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

#if SQLITE_DEBUG>2 && defined(__GLIBC__)
#include <execinfo.h>

    }
  }
}

/* An array to map all upper-case characters into their corresponding
** lower-case character. 
*/
static unsigned char UpperToLower[] = {
      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17,
     18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
     36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
     54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 97, 98, 99,100,101,102,103,
    104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,
    122, 91, 92, 93, 94, 95, 96, 97, 98, 99,100,101,102,103,104,105,106,107,
    108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,
    126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
    144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,
    162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,
    180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,
    198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,
    216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,
    234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,
    252,253,254,255
};


/*
** This function computes a hash on the name of a keyword.
** Case is not significant.
*/
int sqlite3HashNoCase(const char *z, int n){
  int h = 0;

int sqlite3FitsIn64Bits(const char *zNum){
  int i, c;
  if( *zNum=='-' || *zNum=='+' ) zNum++;
  for(i=0; (c=zNum[i])>='0' && c<='9'; i++){}
  return i<19 || (i==19 && memcmp(zNum,"9223372036854775807",19)<=0);
}

#if 1  /* We are now always UTF-8 */
/*
** X is a pointer to the first byte of a UTF-8 character.  Increment
** X so that it points to the next character.  This only works right
** if X points to a well-formed UTF-8 string.
*/
#define sqliteNextChar(X)  while( (0xc0&*++(X))==0x80 ){}
#define sqliteCharVal(X)   sqlite3ReadUtf8(X)

#else /* !defined(SQLITE_UTF8) */
/*
** For iso8859 encoding, the next character is just the next byte.
*/
#define sqliteNextChar(X)  (++(X));
#define sqliteCharVal(X)   ((int)*(X))

#endif /* defined(SQLITE_UTF8) */


#if 1  /* We are now always UTF-8 */
/*
** Convert the UTF-8 character to which z points into a 31-bit
** UCS character.  This only works right if z points to a well-formed
** UTF-8 string.
*/
int sqlite3ReadUtf8(const unsigned char *z){
  int c;
  static const char initVal[] = {
      0,   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12,  13,  14,
     15,  16,  17,  18,  19,  20,  21,  22,  23,  24,  25,  26,  27,  28,  29,
     30,  31,  32,  33,  34,  35,  36,  37,  38,  39,  40,  41,  42,  43,  44,
     45,  46,  47,  48,  49,  50,  51,  52,  53,  54,  55,  56,  57,  58,  59,
     60,  61,  62,  63,  64,  65,  66,  67,  68,  69,  70,  71,  72,  73,  74,
     75,  76,  77,  78,  79,  80,  81,  82,  83,  84,  85,  86,  87,  88,  89,
     90,  91,  92,  93,  94,  95,  96,  97,  98,  99, 100, 101, 102, 103, 104,
    105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119,
    120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134,
    135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
    150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164,
    165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179,
    180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191,   0,   1,   2,
      3,   4,   5,   6,   7,   8,   9,  10,  11,  12,  13,  14,  15,  16,  17,
     18,  19,  20,  21,  22,  23,  24,  25,  26,  27,  28,  29,  30,  31,   0,
      1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12,  13,  14,  15,
      0,   1,   2,   3,   4,   5,   6,   7,   0,   1,   2,   3,   0,   1, 254,
    255,
  };
  c = initVal[*(z++)];
  while( (0xc0&*z)==0x80 ){
    c = (c<<6) | (0x3f&*(z++));
  }
  return c;
}
#endif

/*
** Compare two UTF-8 strings for equality where the first string can
** potentially be a "glob" expression.  Return true (1) if they
** are the same and false (0) if they are different.
**
** Globbing rules:
**
**      '*'       Matches any sequence of zero or more characters.
**
**      '?'       Matches exactly one character.
**
**     [...]      Matches one character from the enclosed list of
**                characters.
**
**     [^...]     Matches one character not in the enclosed list.
**
** With the [...] and [^...] matching, a ']' character can be included
** in the list by making it the first character after '[' or '^'.  A
** range of characters can be specified using '-'.  Example:
** "[a-z]" matches any single lower-case letter.  To match a '-', make
** it the last character in the list.
**
** This routine is usually quick, but can be N**2 in the worst case.
**
** Hints: to match '*' or '?', put them in "[]".  Like this:
**
**         abc[*]xyz        Matches "abc*xyz" only
*/
int 
sqlite3GlobCompare(const unsigned char *zPattern, const unsigned char *zString){
  register int c;
  int invert;
  int seen;
  int c2;

  while( (c = *zPattern)!=0 ){
    switch( c ){
      case '*':
        while( (c=zPattern[1]) == '*' || c == '?' ){
          if( c=='?' ){
            if( *zString==0 ) return 0;
            sqliteNextChar(zString);
          }
          zPattern++;
        }
        if( c==0 ) return 1;
        if( c=='[' ){
          while( *zString && sqlite3GlobCompare(&zPattern[1],zString)==0 ){
            sqliteNextChar(zString);
          }
          return *zString!=0;
        }else{
          while( (c2 = *zString)!=0 ){
            while( c2 != 0 && c2 != c ){ c2 = *++zString; }
            if( c2==0 ) return 0;
            if( sqlite3GlobCompare(&zPattern[1],zString) ) return 1;
            sqliteNextChar(zString);
          }
          return 0;
        }
      case '?': {
        if( *zString==0 ) return 0;
        sqliteNextChar(zString);
        zPattern++;
        break;
      }
      case '[': {
        int prior_c = 0;
        seen = 0;
        invert = 0;
        c = sqliteCharVal(zString);
        if( c==0 ) return 0;
        c2 = *++zPattern;
        if( c2=='^' ){ invert = 1; c2 = *++zPattern; }
        if( c2==']' ){
          if( c==']' ) seen = 1;
          c2 = *++zPattern;
        }
        while( (c2 = sqliteCharVal(zPattern))!=0 && c2!=']' ){
          if( c2=='-' && zPattern[1]!=']' && zPattern[1]!=0 && prior_c>0 ){
            zPattern++;
            c2 = sqliteCharVal(zPattern);
            if( c>=prior_c && c<=c2 ) seen = 1;
            prior_c = 0;
          }else if( c==c2 ){
            seen = 1;
            prior_c = c2;
          }else{
            prior_c = c2;
          }
          sqliteNextChar(zPattern);
        }
        if( c2==0 || (seen ^ invert)==0 ) return 0;
        sqliteNextChar(zString);
        zPattern++;
        break;
      }
      default: {
        if( c != *zString ) return 0;
        zPattern++;
        zString++;
        break;
      }
    }
  }
  return *zString==0;
}

/*
** Change the sqlite.magic from SQLITE_MAGIC_OPEN to SQLITE_MAGIC_BUSY.
** Return an error (non-zero) if the magic was not SQLITE_MAGIC_OPEN
** when this routine is called.
**
** This routine is a attempt to detect if two threads use the