func.c

sqlite-3.4.1,嵌入式数据库.是一个功能强大的开源数据库,给学习和研发以及小型公司的发展带来了全所未有的好处.

      if( c==0 ) return 0;
      c2 = *++zPattern;
      if( c2=='^' ){ invert = 1; c2 = *++zPattern; }
      if( c2==']' ){
        if( c==']' ) seen = 1;
        c2 = *++zPattern;
      }
      while( (c2 = sqlite3ReadUtf8(zPattern))!=0 && c2!=']' ){
        if( c2=='-' && zPattern[1]!=']' && zPattern[1]!=0 && prior_c>0 ){
          zPattern++;
          c2 = sqlite3ReadUtf8(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;
        }
        SQLITE_SKIP_UTF8(zPattern);
      }
      if( c2==0 || (seen ^ invert)==0 ) return 0;
      SQLITE_SKIP_UTF8(zString);
      zPattern++;
    }else if( esc && !prevEscape && sqlite3ReadUtf8(zPattern)==esc){
      prevEscape = 1;
      SQLITE_SKIP_UTF8(zPattern);
    }else{
      if( noCase ){
        if( sqlite3UpperToLower[c] != sqlite3UpperToLower[*zString] ) return 0;
      }else{
        if( c != *zString ) return 0;
      }
      zPattern++;
      zString++;
      prevEscape = 0;
    }
  }
  return *zString==0;
}

/*
** Count the number of times that the LIKE operator (or GLOB which is
** just a variation of LIKE) gets called.  This is used for testing
** only.
*/
#ifdef SQLITE_TEST
int sqlite3_like_count = 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
**
** is implemented as like(B,A).
**
** This same function (with a different compareInfo structure) computes
** the GLOB operator.
*/
static void likeFunc(
  sqlite3_context *context, 
  int argc, 
  sqlite3_value **argv
){
  const unsigned char *zA, *zB;
  int escape = 0;

  zB = sqlite3_value_text(argv[0]);
  zA = sqlite3_value_text(argv[1]);

  /* Limit the length of the LIKE or GLOB pattern to avoid problems
  ** of deep recursion and N*N behavior in patternCompare().
  */
  if( sqlite3_value_bytes(argv[0])>SQLITE_MAX_LIKE_PATTERN_LENGTH ){
    sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
    return;
  }
  assert( zB==sqlite3_value_text(argv[0]) );  /* Encoding did not change */

  if( argc==3 ){
    /* The escape character string must consist of a single UTF-8 character.
    ** Otherwise, return an error.
    */
    const unsigned char *zEsc = sqlite3_value_text(argv[2]);
    if( zEsc==0 ) return;
    if( sqlite3Utf8CharLen((char*)zEsc, -1)!=1 ){
      sqlite3_result_error(context, 
          "ESCAPE expression must be a single character", -1);
      return;
    }
    escape = sqlite3ReadUtf8(zEsc);
  }
  if( zA && zB ){
    struct compareInfo *pInfo = sqlite3_user_data(context);
#ifdef SQLITE_TEST
    sqlite3_like_count++;
#endif
    
    sqlite3_result_int(context, patternCompare(zB, zA, pInfo, escape));
  }
}

/*
** 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.
*/
static void nullifFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  CollSeq *pColl = sqlite3GetFuncCollSeq(context);
  if( sqlite3MemCompare(argv[0], argv[1], pColl)!=0 ){
    sqlite3_result_value(context, argv[0]);
  }
}

/*
** Implementation of the VERSION(*) function.  The result is the version
** of the SQLite library that is running.
*/
static void versionFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  sqlite3_result_text(context, sqlite3_version, -1, SQLITE_STATIC);
}

/* Array for converting from half-bytes (nybbles) into ASCII hex
** digits. */
static const char hexdigits[] = {
  '0', '1', '2', '3', '4', '5', '6', '7',
  '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' 
};

/*
** EXPERIMENTAL - This is not an official function.  The interface may
** change.  This function may disappear.  Do not write code that depends
** on this function.
**
** Implementation of the QUOTE() function.  This function takes a single
** argument.  If the argument is numeric, the return value is the same as
** the argument.  If the argument is NULL, the return value is the string
** "NULL".  Otherwise, the argument is enclosed in single quotes with
** single-quote escapes.
*/
static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  if( argc<1 ) return;
  switch( sqlite3_value_type(argv[0]) ){
    case SQLITE_NULL: {
      sqlite3_result_text(context, "NULL", 4, SQLITE_STATIC);
      break;
    }
    case SQLITE_INTEGER:
    case SQLITE_FLOAT: {
      sqlite3_result_value(context, argv[0]);
      break;
    }
    case SQLITE_BLOB: {
      char *zText = 0;
      char const *zBlob = sqlite3_value_blob(argv[0]);
      int nBlob = sqlite3_value_bytes(argv[0]);
      assert( zBlob==sqlite3_value_blob(argv[0]) ); /* No encoding change */

      if( 2*nBlob+4>SQLITE_MAX_LENGTH ){
        sqlite3_result_error_toobig(context);
        return;
      }
      zText = (char *)sqliteMalloc((2*nBlob)+4); 
      if( !zText ){
        sqlite3_result_error(context, "out of memory", -1);
      }else{
        int i;
        for(i=0; i<nBlob; i++){
          zText[(i*2)+2] = hexdigits[(zBlob[i]>>4)&0x0F];
          zText[(i*2)+3] = hexdigits[(zBlob[i])&0x0F];
        }
        zText[(nBlob*2)+2] = '\'';
        zText[(nBlob*2)+3] = '\0';
        zText[0] = 'X';
        zText[1] = '\'';
        sqlite3_result_text(context, zText, -1, SQLITE_TRANSIENT);
        sqliteFree(zText);
      }
      break;
    }
    case SQLITE_TEXT: {
      int i,j;
      u64 n;
      const unsigned char *zArg = sqlite3_value_text(argv[0]);
      char *z;

      if( zArg==0 ) return;
      for(i=0, n=0; zArg[i]; i++){ if( zArg[i]=='\'' ) n++; }
      if( i+n+3>SQLITE_MAX_LENGTH ){
        sqlite3_result_error_toobig(context);
        return;
      }
      z = sqliteMalloc( i+n+3 );
      if( z==0 ) return;
      z[0] = '\'';
      for(i=0, j=1; zArg[i]; i++){
        z[j++] = zArg[i];
        if( zArg[i]=='\'' ){
          z[j++] = '\'';
        }
      }
      z[j++] = '\'';
      z[j] = 0;
      sqlite3_result_text(context, z, j, SQLITE_TRANSIENT);
      sqliteFree(z);
    }
  }
}

/*
** The hex() function.  Interpret the argument as a blob.  Return
** a hexadecimal rendering as text.
*/
static void hexFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  int i, n;
  const unsigned char *pBlob;
  char *zHex, *z;
  assert( argc==1 );
  pBlob = sqlite3_value_blob(argv[0]);
  n = sqlite3_value_bytes(argv[0]);
  if( n*2+1>SQLITE_MAX_LENGTH ){
    sqlite3_result_error_toobig(context);
    return;
  }
  assert( pBlob==sqlite3_value_blob(argv[0]) );  /* No encoding change */
  z = zHex = sqlite3_malloc(n*2 + 1);
  if( zHex==0 ) return;
  for(i=0; i<n; i++, pBlob++){
    unsigned char c = *pBlob;
    *(z++) = hexdigits[(c>>4)&0xf];
    *(z++) = hexdigits[c&0xf];
  }
  *z = 0;
  sqlite3_result_text(context, zHex, n*2, sqlite3_free);
}

/*
** The zeroblob(N) function returns a zero-filled blob of size N bytes.
*/
static void zeroblobFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  i64 n;
  assert( argc==1 );
  n = sqlite3_value_int64(argv[0]);
  if( n>SQLITE_MAX_LENGTH ){
    sqlite3_result_error_toobig(context);
  }else{
    sqlite3_result_zeroblob(context, n);
  }
}

/*
** The replace() function.  Three arguments are all strings: call
** them A, B, and C. The result is also a string which is derived
** from A by replacing every occurance of B with C.  The match
** must be exact.  Collating sequences are not used.
*/
static void replaceFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const unsigned char *zStr;        /* The input string A */
  const unsigned char *zPattern;    /* The pattern string B */
  const unsigned char *zRep;        /* The replacement string C */
  unsigned char *zOut;              /* The output */
  int nStr;                /* Size of zStr */
  int nPattern;            /* Size of zPattern */
  int nRep;                /* Size of zRep */
  i64 nOut;                /* Maximum size of zOut */
  int loopLimit;           /* Last zStr[] that might match zPattern[] */
  int i, j;                /* Loop counters */

  assert( argc==3 );
  zStr = sqlite3_value_text(argv[0]);
  if( zStr==0 ) return;
  nStr = sqlite3_value_bytes(argv[0]);
  assert( zStr==sqlite3_value_text(argv[0]) );  /* No encoding change */
  zPattern = sqlite3_value_text(argv[1]);
  if( zPattern==0 || zPattern[0]==0 ) return;
  nPattern = sqlite3_value_bytes(argv[1]);
  assert( zPattern==sqlite3_value_text(argv[1]) );  /* No encoding change */
  zRep = sqlite3_value_text(argv[2]);
  if( zRep==0 ) return;
  nRep = sqlite3_value_bytes(argv[2]);
  assert( zRep==sqlite3_value_text(argv[2]) );
  nOut = nStr + 1;
  assert( nOut<SQLITE_MAX_LENGTH );
  zOut = sqlite3_malloc((int)nOut);
  if( zOut==0 ){
    return;
  }
  loopLimit = nStr - nPattern;  
  for(i=j=0; i<=loopLimit; i++){
    if( zStr[i]!=zPattern[0] || memcmp(&zStr[i], zPattern, nPattern) ){
      zOut[j++] = zStr[i];
    }else{
      nOut += nRep - nPattern;
      if( nOut>=SQLITE_MAX_LENGTH ){
        sqlite3_result_error_toobig(context);
        sqlite3_free(zOut);
        return;
      }
      zOut = sqlite3_realloc(zOut, (int)nOut);
      if( zOut==0 ){
        return;
      }
      memcpy(&zOut[j], zRep, nRep);
      j += nRep;
      i += nPattern-1;
    }
  }
  assert( j+nStr-i+1==nOut );
  memcpy(&zOut[j], &zStr[i], nStr-i);
  j += nStr - i;
  assert( j<=nOut );
  zOut[j] = 0;
  sqlite3_result_text(context, (char*)zOut, j, sqlite3_free);
}

/*
** Implementation of the TRIM(), LTRIM(), and RTRIM() functions.
** The userdata is 0x1 for left trim, 0x2 for right trim, 0x3 for both.
*/
static void trimFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const unsigned char *zIn;         /* Input string */
  const unsigned char *zCharSet;    /* Set of characters to trim */
  int nIn;                          /* Number of bytes in input */
  int flags;                        /* 1: trimleft  2: trimright  3: trim */
  int i;                            /* Loop counter */
  unsigned char *aLen;              /* Length of each character in zCharSet */
  const unsigned char **azChar;     /* Individual characters in zCharSet */
  int nChar;                        /* Number of characters in zCharSet */

  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
    return;
  }
  zIn = sqlite3_value_text(argv[0]);
  if( zIn==0 ) return;
  nIn = sqlite3_value_bytes(argv[0]);
  assert( zIn==sqlite3_value_text(argv[0]) );
  if( argc==1 ){
    static const unsigned char lenOne[] = { 1 };
    static const unsigned char *azOne[] = { (u8*)" " };
    nChar = 1;
    aLen = (u8*)lenOne;
    azChar = azOne;
    zCharSet = 0;
  }else if( (zCharSet = sqlite3_value_text(argv[1]))==0 ){
    return;
  }else{
    const unsigned char *z;
    for(z=zCharSet, nChar=0; *z; nChar++){
      SQLITE_SKIP_UTF8(z);
    }
    if( nChar>0 ){
      azChar = sqlite3_malloc( nChar*(sizeof(char*)+1) );
      if( azChar==0 ){
        return;
      }
      aLen = (unsigned char*)&azChar[nChar];
      for(z=zCharSet, nChar=0; *z; nChar++){
        azChar[nChar] = z;
        SQLITE_SKIP_UTF8(z);
        aLen[nChar] = z - azChar[nChar];
      }
    }
  }
  if( nChar>0 ){
    flags = (int)sqlite3_user_data(context);
    if( flags & 1 ){
      while( nIn>0 ){
        int len;
        for(i=0; i<nChar; i++){
          len = aLen[i];
          if( memcmp(zIn, azChar[i], len)==0 ) break;
        }
        if( i>=nChar ) break;
        zIn += len;
        nIn -= len;
      }
    }
    if( flags & 2 ){
      while( nIn>0 ){
        int len;
        for(i=0; i<nChar; i++){
          len = aLen[i];
          if( len<=nIn && memcmp(&zIn[nIn-len],azChar[i],len)==0 ) break;
        }
        if( i>=nChar ) break;
        nIn -= len;
      }
    }
    if( zCharSet ){
      sqlite3_free(azChar);
    }
  }
  sqlite3_result_text(context, (char*)zIn, nIn, SQLITE_TRANSIENT);
}

#ifdef SQLITE_SOUNDEX
/*
** Compute the soundex encoding of a word.
*/
static void soundexFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  char zResult[8];
  const u8 *zIn;
  int i, j;
  static const unsigned char iCode[] = {
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
  };
  assert( argc==1 );
  zIn = (u8*)sqlite3_value_text(argv[0]);
  if( zIn==0 ) zIn = (u8*)"";
  for(i=0; zIn[i] && !isalpha(zIn[i]); i++){}
  if( zIn[i] ){
    u8 prevcode = iCode[zIn[i]&0x7f];
    zResult[0] = toupper(zIn[i]);
    for(j=1; j<4 && zIn[i]; i++){
      int code = iCode[zIn[i]&0x7f];
      if( code>0 ){
        if( code!=prevcode ){
          prevcode = code;
          zResult[j++] = code + '0';
        }
      }else{
        prevcode = 0;
      }
    }
    while( j<4 ){
      zResult[j++] = '0';
    }
    zResult[j] = 0;
    sqlite3_result_text(context, zResult, 4, SQLITE_TRANSIENT);
  }else{
    sqlite3_result_text(context, "?000", 4, SQLITE_STATIC);
  }
}
#endif

#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** A function that loads a shared-library extension then returns NULL.
*/
static void loadExt(sqlite3_context *context, int argc, sqlite3_value **argv){
  const char *zFile = (const char *)sqlite3_value_text(argv[0]);
  const char *zProc;
  sqlite3 *db = sqlite3_user_data(context);
  char *zErrMsg = 0;

  if( argc==2 ){
    zProc = (const char *)sqlite3_value_text(argv[1]);
  }else{
    zProc = 0;
  }
  if( zFile && sqlite3_load_extension(db, zFile, zProc, &zErrMsg) ){
    sqlite3_result_error(context, zErrMsg, -1);
    sqlite3_free(zErrMsg);
  }
}
#endif

#ifdef SQLITE_TEST
/*