src/util.c

/*
** Copyright (c) 1999, 2000 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public
** License as published by the Free Software Foundation; either
** version 2 of the License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** General Public License for more details.
** 
** You should have received a copy of the GNU General Public
** License along with this library; if not, write to the
** Free Software Foundation, Inc., 59 Temple Place - Suite 330,
** Boston, MA  02111-1307, USA.
**
** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.16 2000/10/11 19:28:52 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** If MEMORY_DEBUG is defined, then use versions of malloc() and
** free() that track memory usage and check for buffer overruns.
*/
#ifdef MEMORY_DEBUG

/*
** Allocate new memory and set it to zero.  Return NULL if
** no memory is available.
*/
void *sqliteMalloc_(int n, char *zFile, int line){
  void *p;
  int *pi;
  int k;
  sqlite_nMalloc++;
  if( sqlite_iMallocFail>=0 ){
    sqlite_iMallocFail--;
    if( sqlite_iMallocFail==0 ) return 0;
  }
  k = (n+sizeof(int)-1)/sizeof(int);
  pi = malloc( (3+k)*sizeof(int));
  if( pi==0 ) return 0;
  pi[0] = 0xdead1122;
  pi[1] = n;
  pi[k+2] = 0xdead3344;
  p = &pi[2];
  memset(p, 0, n);
#if MEMORY_DEBUG>1
  fprintf(stderr,"malloc %d bytes at 0x%x from %s:%d\n", n, (int)p, zFile,line);
#endif
  return p;
}

/*
** Free memory previously obtained from sqliteMalloc()
*/
void sqliteFree_(void *p, char *zFile, int line){
  if( p ){
    int *pi, k, n;
    pi = p;
    pi -= 2;
    sqlite_nFree++;
    if( pi[0]!=0xdead1122 ){
      fprintf(stderr,"Low-end memory corruption at 0x%x\n", (int)p);
      return;
    }
    n = pi[1];
    k = (n+sizeof(int)-1)/sizeof(int);
    if( pi[k+2]!=0xdead3344 ){
      fprintf(stderr,"High-end memory corruption at 0x%x\n", (int)p);
      return;
    }
    memset(pi, 0xff, (k+3)*sizeof(int));
#if MEMORY_DEBUG>1
    fprintf(stderr,"free %d bytes at 0x%x from %s:%d\n", n, (int)p, zFile,line);
#endif
    free(pi);
  }
}

/*
** Resize a prior allocation.  If p==0, then this routine
** works just like sqliteMalloc().  If n==0, then this routine
** works just like sqliteFree().
*/
void *sqliteRealloc_(void *oldP, int n, char *zFile, int line){
  int *oldPi, *pi, k, oldN, oldK;
  void *p;
  if( oldP==0 ){
    return sqliteMalloc_(n,zFile,line);
  }
  if( n==0 ){
    sqliteFree_(oldP,zFile,line);
    return 0;
  }
  oldPi = oldP;
  oldPi -= 2;
  if( oldPi[0]!=0xdead1122 ){
    fprintf(stderr,"Low-end memory corruption in realloc at 0x%x\n", (int)p);
    return 0;
  }
  oldN = oldPi[1];
  oldK = (oldN+sizeof(int)-1)/sizeof(int);
  if( oldPi[oldK+2]!=0xdead3344 ){
    fprintf(stderr,"High-end memory corruption in realloc at 0x%x\n", (int)p);
    return 0;
  }
  k = (n + sizeof(int) - 1)/sizeof(int);
  pi = malloc( (k+3)*sizeof(int) );
  pi[0] = 0xdead1122;
  pi[1] = n;
  pi[k+2] = 0xdead3344;
  p = &pi[2];
  memcpy(p, oldP, n>oldN ? oldN : n);
  if( n>oldN ){
    memset(&((char*)p)[oldN], 0, n-oldN);
  }
  memset(oldPi, 0, (oldK+3)*sizeof(int));
  free(oldPi);
#if MEMORY_DEBUG>1
  fprintf(stderr,"realloc %d to %d bytes at 0x%x to 0x%x at %s:%d\n", oldN, n,
    (int)oldP, (int)p, zFile, line);
#endif
  return p;
}

/*
** Make a duplicate of a string into memory obtained from malloc()
** Free the original string using sqliteFree().
*/
void sqliteStrRealloc(char **pz){
  char *zNew;
  if( pz==0 || *pz==0 ) return;
  zNew = malloc( strlen(*pz) + 1 );
  if( zNew ) strcpy(zNew, *pz);
  sqliteFree(*pz);
  *pz = zNew;
}

/*
** Make a copy of a string in memory obtained from sqliteMalloc()
*/
char *sqliteStrDup_(const char *z, char *zFile, int line){
  char *zNew = sqliteMalloc_(strlen(z)+1, zFile, line);
  if( zNew ) strcpy(zNew, z);
  return zNew;
}
char *sqliteStrNDup_(const char *z, int n, char *zFile, int line){
  char *zNew = sqliteMalloc_(n+1, zFile, line);
  if( zNew ){
    memcpy(zNew, z, n);
    zNew[n] = 0;
  }
  return zNew;
}
#endif /* MEMORY_DEBUG */

/*
** The following versions of malloc() and free() are for use in a
** normal build.
*/
#if !defined(MEMORY_DEBUG)

/*
** Allocate new memory and set it to zero.  Return NULL if
** no memory is available.
*/
void *sqliteMalloc(int n){
  void *p = malloc(n);
  if( p==0 ) return 0;
  memset(p, 0, n);
  return p;
}

/*
** Free memory previously obtained from sqliteMalloc()
*/
void sqliteFree(void *p){
  if( p ){
    free(p);
  }
}

/*
** Resize a prior allocation.  If p==0, then this routine
** works just like sqliteMalloc().  If n==0, then this routine
** works just like sqliteFree().
*/
void *sqliteRealloc(void *p, int n){
  if( p==0 ){
    return sqliteMalloc(n);
  }
  if( n==0 ){
    sqliteFree(p);
    return 0;
  }
  return realloc(p, n);
}

/*
** Make a copy of a string in memory obtained from sqliteMalloc()
*/
char *sqliteStrDup(const char *z){
  char *zNew = sqliteMalloc(strlen(z)+1);
  if( zNew ) strcpy(zNew, z);
  return zNew;
}
char *sqliteStrNDup(const char *z, int n){
  char *zNew = sqliteMalloc(n+1);
  if( zNew ){
    memcpy(zNew, z, n);
    zNew[n] = 0;
  }
  return zNew;
}
#endif /* !defined(MEMORY_DEBUG) */

/*
** Create a string from the 2nd and subsequent arguments (up to the
** first NULL argument), store the string in memory obtained from
** sqliteMalloc() and make the pointer indicated by the 1st argument
** point to that string.
*/
void sqliteSetString(char **pz, const char *zFirst, ...){
  va_list ap;
  int nByte;
  const char *z;
  char *zResult;

  if( pz==0 ) return;
  nByte = strlen(zFirst) + 1;
  va_start(ap, zFirst);
  while( (z = va_arg(ap, const char*))!=0 ){
    nByte += strlen(z);
  }
  va_end(ap);
  sqliteFree(*pz);
  *pz = zResult = sqliteMalloc( nByte );
  if( zResult==0 ) return;
  strcpy(zResult, zFirst);
  zResult += strlen(zResult);
  va_start(ap, zFirst);
  while( (z = va_arg(ap, const char*))!=0 ){
    strcpy(zResult, z);
    zResult += strlen(zResult);
  }
  va_end(ap);
#ifdef MEMORY_DEBUG
#if MEMORY_DEBUG>1
  fprintf(stderr,"string at 0x%x is %s\n", (int)*pz, *pz);
#endif
#endif
}

/*
** Works like sqliteSetString, but each string is now followed by
** a length integer.  -1 means use the whole string.
*/
void sqliteSetNString(char **pz, ...){
  va_list ap;
  int nByte;
  const char *z;
  char *zResult;
  int n;

  if( pz==0 ) return;
  nByte = 0;
  va_start(ap, pz);
  while( (z = va_arg(ap, const char*))!=0 ){
    n = va_arg(ap, int);
    if( n<=0 ) n = strlen(z);
    nByte += n;
  }
  va_end(ap);
  sqliteFree(*pz);
  *pz = zResult = sqliteMalloc( nByte + 1 );
  if( zResult==0 ) return;
  va_start(ap, pz);
  while( (z = va_arg(ap, const char*))!=0 ){
    n = va_arg(ap, int);
    if( n<=0 ) n = strlen(z);
    strncpy(zResult, z, n);
    zResult += n;
  }
  *zResult = 0;
#ifdef MEMORY_DEBUG
#if MEMORY_DEBUG>1
  fprintf(stderr,"string at 0x%x is %s\n", (int)*pz, *pz);
#endif
#endif
  va_end(ap);
}

/*
** Convert an SQL-style quoted string into a normal string by removing
** the quote characters.  The conversion is done in-place.  If the
** input does not begin with a quote character, then this routine
** is a no-op.
*/
void sqliteDequote(char *z){
  int quote;
  int i, j;
  quote = z[0];
  if( quote!='\'' && quote!='"' ) return;
  for(i=1, j=0; z[i]; i++){
    if( z[i]==quote ){
      if( z[i+1]==quote ){
        z[j++] = quote;
        i++;
      }else{
        z[j++] = 0;
        break;
      }
    }else{
      z[j++] = z[i];
    }
  }
}

/* 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 sqliteHashNoCase(const char *z, int n){
  int h = 0;
  int c;
  if( n<=0 ) n = strlen(z);
  while( n-- > 0 && (c = *z++)!=0 ){
    h = h<<3 ^ h ^ UpperToLower[c];
  }
  if( h<0 ) h = -h;
  return h;
}

/*
** Some systems have stricmp().  Others have strcasecmp().  Because
** there is no consistency, we will define our own.
*/
int sqliteStrICmp(const char *zLeft, const char *zRight){
  register unsigned char *a, *b;
  a = (unsigned char *)zLeft;
  b = (unsigned char *)zRight;
  while( *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
  return *a - *b;
}
int sqliteStrNICmp(const char *zLeft, const char *zRight, int N){
  register unsigned char *a, *b;
  a = (unsigned char *)zLeft;
  b = (unsigned char *)zRight;
  while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
  return N<0 ? 0 : *a - *b;
}

/* Notes on string comparisions.
**
** We want the main string comparision function used for sorting to
** sort both numbers and alphanumeric words into the correct sequence.
** The same routine should do both without prior knowledge of which
** type of text the input represents.  It should even work for strings
** which are a mixture of text and numbers.
**
** To accomplish this, we keep track of a state number while scanning
** the two strings.  The states are as follows:
**
**    1      Beginning of word
**    2      Arbitrary text
**    3      Integer
**    4      Negative integer
**    5      Real number
**    6      Negative real
**
** The scan begins in state 1, beginning of word.  Transitions to other
** states are determined by characters seen, as shown in the following
** chart:
**
**      Current State         Character Seen  New State
**      --------------------  --------------  -------------------
**      0 Beginning of word   "-"             3 Negative integer
**                            digit           2 Integer
**                            space           0 Beginning of word
**                            otherwise       1 Arbitrary text
**
**      1 Arbitrary text      space           0 Beginning of word
**                            digit           2 Integer
**                            otherwise       1 Arbitrary text
**
**      2 Integer             space           0 Beginning of word
**                            "."             4 Real number
**                            digit           2 Integer
**                            otherwise       1 Arbitrary text
**
**      3 Negative integer    space           0 Beginning of word
**                            "."             5 Negative Real num
**                            digit           3 Negative integer
**                            otherwise       1 Arbitrary text
**
**      4 Real number         space           0 Beginning of word
**                            digit           4 Real number
**                            otherwise       1 Arbitrary text
**
**      5 Negative real num   space           0 Beginning of word
**                            digit           5 Negative real num
**                            otherwise       1 Arbitrary text
**
** To implement this state machine, we first classify each character
** into on of the following categories:
**
**      0  Text
**      1  Space
**      2  Digit
**      3  "-"
**      4  "."
**
** Given an arbitrary character, the array charClass[] maps that character
** into one of the atove categories.
*/
static const unsigned char charClass[] = {
        /* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
/* 0x */   0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0,
/* 1x */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 2x */   1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 4, 0,
/* 3x */   2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 0, 0, 0, 0, 0,
/* 4x */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 5x */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 6x */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 7x */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 8x */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 9x */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* Ax */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* Bx */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* Cx */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* Dx */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* Ex */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* Fx */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};
#define N_CHAR_CLASS 5

/*
** Given the current state number (0 thru 5), this array figures
** the new state number given the character class.
*/
static const unsigned char stateMachine[] = {
 /* Text,  Space, Digit, "-", "." */
      1,      0,    2,    3,   1,      /* State 0: Beginning of word */
      1,      0,    2,    1,   1,      /* State 1: Arbitrary text */
      1,      0,    2,    1,   4,      /* State 2: Integer */
      1,      0,    3,    1,   5,      /* State 3: Negative integer */
      1,      0,    4,    1,   1,      /* State 4: Real number */
      1,      0,    5,    1,   1,      /* State 5: Negative real num */
};

/* This routine does a comparison of two strings.  Case is used only
** if useCase!=0.  Numbers compare in numerical order.
*/
static int privateStrCmp(const char *atext, const char *btext, int useCase){
  register unsigned char *a, *b, *map, ca, cb;
  int result;
  register int cclass = 0;

  a = (unsigned char *)atext;
  b = (unsigned char *)btext;
  if( useCase ){
    do{
      if( (ca= *a++)!=(cb= *b++) ) break;
      cclass = stateMachine[cclass*N_CHAR_CLASS + charClass[ca]];
    }while( ca!=0 );
  }else{
    map = UpperToLower;
    do{
      if( (ca=map[*a++])!=(cb=map[*b++]) ) break;
      cclass = stateMachine[cclass*N_CHAR_CLASS + charClass[ca]];
    }while( ca!=0 );
  }
  switch( cclass ){
    case 0:
    case 1: {
      if( isdigit(ca) && isdigit(cb) ){
        cclass = 2;
      }
      break;
    }
    default: {
      break;
    }
  }
  switch( cclass ){
    case 2:
    case 3: {
      if( isdigit(ca) ){
        if( isdigit(cb) ){
          int acnt, bcnt;
          acnt = bcnt = 0;
          while( isdigit(*a++) ) acnt++;
          while( isdigit(*b++) ) bcnt++;
          result = acnt - bcnt;
          if( result==0 ) result = ca-cb;
        }else{
          result = 1;
        }
      }else if( isdigit(cb) ){
        result = -1;
      }else if( ca=='.' ){
        result = 1;
      }else if( cb=='.' ){
        result = -1;
      }else{
        result = ca - cb;
        cclass = 2;
      }
      if( cclass==3 ) result = -result;
      break;
    }
    case 0:
    case 1:
    case 4: {
      result = ca - cb;
      break;
    }
    case 5: {
      result = cb - ca;
    };
  }
  return result;
}

/*
** Do a comparison of pure numerics.  If either string is not a pure
** numeric, then return 0.  Otherwise return 1 and set *pResult to be
** negative, zero or positive if the first string are numerially less than
** equal to, or greater than the second.
*/
static int privateCompareNum(const char *a, const char *b, int *pResult){
  char *endPtr;
  double rA, rB;
  int isNumA, isNumB;
  if( isdigit(*a) || ((*a=='-' || *a=='+') && isdigit(a[1])) ){
    rA = strtod(a, &endPtr);
    isNumA = *endPtr==0;
  }else{
    isNumA = 0;
  }
  if( isdigit(*b) || ((*b=='-' || *b=='+') && isdigit(b[1])) ){
    rB = strtod(b, &endPtr);
    isNumB = *endPtr==0;
  }else{
    isNumB = 0;
  }
  if( isNumB==0 && isNumA==0 ) return 0;
  if( isNumA!=isNumB ){
    *pResult =  isNumA - isNumB;
  }else if( rA<rB ){
    *pResult = -1;
  }else if( rA>rB ){
    *pResult = 1;
  }else{
    *pResult = 0;
  }
  return 1;
}

/* This comparison routine is what we use for comparison operations
** in an SQL expression.  (Ex:  name<'Hello' or value<5).  Compare two
** strings.  Use case only as a tie-breaker.  Numbers compare in
** numerical order.
*/
int sqliteCompare(const char *atext, const char *btext){
  int result;
  if( !privateCompareNum(atext, btext, &result) || result==0 ){
    result = privateStrCmp(atext, btext, 0);
    if( result==0 ) result = privateStrCmp(atext, btext, 1);
  }
  return result;
}

/*
** If you compile just this one file with the -DTEST_COMPARE=1 option,
** it generates a program to test the comparisons routines.  
*/
#ifdef TEST_COMPARE
#include <stdlib.h>
#include <stdio.h>
int sortCmp(const char **a, const char **b){
  return sqliteCompare(*a, *b);
}
int main(int argc, char **argv){
  int i, j, k, n, cnt;
  static char *azStr[] = {
     "abc", "aBc", "abcd", "aBcd", 
     "123", "124", "1234", "-123", "-124", "-1234", "+124",
     "123.45", "123.456", "123.46", "-123.45", "-123.46", "-123.456", 
     "x9", "x10", "x-9", "x-10", "X9", "X10",
     "1.234e+02", "+123", "1.23E2", "1.2345e+2", "-1.2345e2", "+w"
  };
  n = sizeof(azStr)/sizeof(azStr[0]);
  qsort(azStr, n, sizeof(azStr[0]), sortCmp);
  for(i=0; i<n; i++){
    printf("%s\n", azStr[i]);
  }
  printf("Sanity1...");
  fflush(stdout);
  cnt = 0;
  for(i=0; i<n-1; i++){
    char *a = azStr[i];
    for(j=i+1; j<n; j++){
      char *b = azStr[j];
      if( sqliteCompare(a,b) != -sqliteCompare(b,a) ){
        printf("Failed!  \"%s\" vs \"%s\"\n", a, b);
        i = j = n;
      }
      cnt++;
    }
  }
  if( i<n ){
    printf(" OK (%d)\n", cnt);
  }
  printf("Sanity2...");
  fflush(stdout);
  cnt = 0;
  for(i=0; i<n; i++){
    char *a = azStr[i];
    for(j=0; j<n; j++){
      char *b = azStr[j];
      for(k=0; k<n; k++){
        char *c = azStr[k];
        int x1, x2, x3, success;
        x1 = sqliteCompare(a,b);
        x2 = sqliteCompare(b,c);
        x3 = sqliteCompare(a,c);
        if( x1==0 ){
          success = x2==x3;
        }else if( x1<0 ){
          success = (x2<=0 && x3<=0) || x2>0;
        }else{
          success = (x2>=0 && x3>=0) || x2<0;
        }
        if( !success ){
          printf("Failed!  \"%s\" vs \"%s\" vs \"%s\"\n", a, b, c);
          i = j = k = n+1;
        }
        cnt++;
      }
    }
  }
  if( i<n+1 ){
    printf(" OK (%d)\n", cnt);
  }
  return 0;
}
#endif

/*
** This routine is used for sorting.  Each key is a list of one or more
** null-terminated strings.  The list is terminated by two nulls in
** a row.  For example, the following text is key with three strings:
**
**            +one\000-two\000+three\000\000
**
** Both arguments will have the same number of strings.  This routine
** returns negative, zero, or positive if the first argument is less
** than, equal to, or greater than the first.  (Result is a-b).
**
** Every string begins with either a "+" or "-" character.  If the
** character is "-" then the return value is negated.  This is done
** to implement a sort in descending order.
*/
int sqliteSortCompare(const char *a, const char *b){
  int len;
  int res = 0;

  while( res==0 && *a && *b ){
    res = sqliteCompare(&a[1], &b[1]);
    if( res==0 ){
      len = strlen(a) + 1;
      a += len;
      b += len;
    }
  }
  if( *a=='-' ) res = -res;
  return res;
}

/*
** Compare two 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 sqliteGlobCompare(const char *zPattern, const char *zString){
  register char c;
  int invert;
  int seen;
  char c2;

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

/*
** Compare two 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.
**
** This routine is just an adaptation of the sqliteGlobCompare()
** routine above.
*/
int 
sqliteLikeCompare(const unsigned char *zPattern, const unsigned char *zString){
  register char c;
  char c2;

  while( (c = UpperToLower[*zPattern])!=0 ){
    switch( c ){
      case '%':
        while( zPattern[1]=='%' ) zPattern++;
        if( zPattern[1]==0 ) return 1;
        c = UpperToLower[0xff & zPattern[1]];
        if( c=='_' ){
          while( *zString && sqliteLikeCompare(&zPattern[1],zString)==0 ){
            zString++;
          }
          return *zString!=0;
        }else{
          while( (c2 = UpperToLower[*zString])!=0 ){
            while( c2 != 0 && c2 != c ){ c2 = UpperToLower[*++zString]; }
            if( c2==0 ) return 0;
            if( sqliteLikeCompare(&zPattern[1],zString) ) return 1;
            zString++;
          }
          return 0;
        }
      case '_':
        if( *zString==0 ) return 0;
        break;
      default:
        if( c != UpperToLower[*zString] ) return 0;
        break;
    }
    zPattern++;
    zString++;
  }
  return *zString==0;
}