niceSOFT/sqlite: Official Git mirror of the SQLite source tree

ext/misc/spellfix.c
3 076 строк101 KB
stephan
Squash sign-comparison warnings reported in [forum:5e605a763a65c3f8 | forum post 5e605a763a65c3f8].
27 сен 2024, 19:20
27 сен 2024, 19:20c707b2e
/*
** 2012 April 10
**
** 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.
**
*************************************************************************
**
** This module implements the spellfix1 VIRTUAL TABLE that can be used
** to search a large vocabulary for close matches.  See separate
** documentation (http://www.sqlite.org/spellfix1.html) for details.
*/
#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1

#ifndef SQLITE_AMALGAMATION
# if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
#  define NDEBUG 1
# endif
# if defined(NDEBUG) && defined(SQLITE_DEBUG)
#  undef NDEBUG
# endif
# include <string.h>
# include <stdio.h>
# include <stdlib.h>
# include <assert.h>
# define ALWAYS(X)  1
# define NEVER(X)   0
  typedef unsigned char u8;
  typedef unsigned short u16;
#endif
#include <ctype.h>

#ifndef SQLITE_OMIT_VIRTUALTABLE

/*
** Character classes for ASCII characters:
**
**   0   ''        Silent letters:   H W
**   1   'A'       Any vowel:   A E I O U (Y)
**   2   'B'       A bilabeal stop or fricative:  B F P V W
**   3   'C'       Other fricatives or back stops:  C G J K Q S X Z
**   4   'D'       Alveolar stops:  D T
**   5   'H'       Letter H at the beginning of a word
**   6   'L'       Glide:  L
**   7   'R'       Semivowel:  R
**   8   'M'       Nasals:  M N
**   9   'Y'       Letter Y at the beginning of a word.
**   10  '9'       Digits: 0 1 2 3 4 5 6 7 8 9
**   11  ' '       White space
**   12  '?'       Other.
*/
#define CCLASS_SILENT         0
#define CCLASS_VOWEL          1
#define CCLASS_B              2
#define CCLASS_C              3
#define CCLASS_D              4
#define CCLASS_H              5
#define CCLASS_L              6
#define CCLASS_R              7
#define CCLASS_M              8
#define CCLASS_Y              9
#define CCLASS_DIGIT         10
#define CCLASS_SPACE         11
#define CCLASS_OTHER         12

/*
** The following table gives the character class for non-initial ASCII
** characters.
*/
static const unsigned char midClass[] = {
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_SPACE,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_SPACE,    /*   */ CCLASS_SPACE,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_SPACE,
 /* ! */ CCLASS_OTHER,    /* " */ CCLASS_OTHER,   /* # */ CCLASS_OTHER,
 /* $ */ CCLASS_OTHER,    /* % */ CCLASS_OTHER,   /* & */ CCLASS_OTHER,
 /* ' */ CCLASS_SILENT,   /* ( */ CCLASS_OTHER,   /* ) */ CCLASS_OTHER,
 /* * */ CCLASS_OTHER,    /* + */ CCLASS_OTHER,   /* , */ CCLASS_OTHER,
 /* - */ CCLASS_OTHER,    /* . */ CCLASS_OTHER,   /* / */ CCLASS_OTHER,
 /* 0 */ CCLASS_DIGIT,    /* 1 */ CCLASS_DIGIT,   /* 2 */ CCLASS_DIGIT,
 /* 3 */ CCLASS_DIGIT,    /* 4 */ CCLASS_DIGIT,   /* 5 */ CCLASS_DIGIT,
 /* 6 */ CCLASS_DIGIT,    /* 7 */ CCLASS_DIGIT,   /* 8 */ CCLASS_DIGIT,
 /* 9 */ CCLASS_DIGIT,    /* : */ CCLASS_OTHER,   /* ; */ CCLASS_OTHER,
 /* < */ CCLASS_OTHER,    /* = */ CCLASS_OTHER,   /* > */ CCLASS_OTHER,
 /* ? */ CCLASS_OTHER,    /* @ */ CCLASS_OTHER,   /* A */ CCLASS_VOWEL,
 /* B */ CCLASS_B,        /* C */ CCLASS_C,       /* D */ CCLASS_D,
 /* E */ CCLASS_VOWEL,    /* F */ CCLASS_B,       /* G */ CCLASS_C,
 /* H */ CCLASS_SILENT,   /* I */ CCLASS_VOWEL,   /* J */ CCLASS_C,
 /* K */ CCLASS_C,        /* L */ CCLASS_L,       /* M */ CCLASS_M,
 /* N */ CCLASS_M,        /* O */ CCLASS_VOWEL,   /* P */ CCLASS_B,
 /* Q */ CCLASS_C,        /* R */ CCLASS_R,       /* S */ CCLASS_C,
 /* T */ CCLASS_D,        /* U */ CCLASS_VOWEL,   /* V */ CCLASS_B,
 /* W */ CCLASS_B,        /* X */ CCLASS_C,       /* Y */ CCLASS_VOWEL,
 /* Z */ CCLASS_C,        /* [ */ CCLASS_OTHER,   /* \ */ CCLASS_OTHER,
 /* ] */ CCLASS_OTHER,    /* ^ */ CCLASS_OTHER,   /* _ */ CCLASS_OTHER,
 /* ` */ CCLASS_OTHER,    /* a */ CCLASS_VOWEL,   /* b */ CCLASS_B,
 /* c */ CCLASS_C,        /* d */ CCLASS_D,       /* e */ CCLASS_VOWEL,
 /* f */ CCLASS_B,        /* g */ CCLASS_C,       /* h */ CCLASS_SILENT,
 /* i */ CCLASS_VOWEL,    /* j */ CCLASS_C,       /* k */ CCLASS_C,
 /* l */ CCLASS_L,        /* m */ CCLASS_M,       /* n */ CCLASS_M,
 /* o */ CCLASS_VOWEL,    /* p */ CCLASS_B,       /* q */ CCLASS_C,
 /* r */ CCLASS_R,        /* s */ CCLASS_C,       /* t */ CCLASS_D,
 /* u */ CCLASS_VOWEL,    /* v */ CCLASS_B,       /* w */ CCLASS_B,
 /* x */ CCLASS_C,        /* y */ CCLASS_VOWEL,   /* z */ CCLASS_C,
 /* { */ CCLASS_OTHER,    /* | */ CCLASS_OTHER,   /* } */ CCLASS_OTHER,
 /* ~ */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   
};
/* 
** This tables gives the character class for ASCII characters that form the
** initial character of a word.  The only difference from midClass is with
** the letters H, W, and Y.
*/
static const unsigned char initClass[] = {
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_SPACE,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_SPACE,    /*   */ CCLASS_SPACE,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_OTHER,
 /*   */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   /*   */ CCLASS_SPACE,
 /* ! */ CCLASS_OTHER,    /* " */ CCLASS_OTHER,   /* # */ CCLASS_OTHER,
 /* $ */ CCLASS_OTHER,    /* % */ CCLASS_OTHER,   /* & */ CCLASS_OTHER,
 /* ' */ CCLASS_OTHER,    /* ( */ CCLASS_OTHER,   /* ) */ CCLASS_OTHER,
 /* * */ CCLASS_OTHER,    /* + */ CCLASS_OTHER,   /* , */ CCLASS_OTHER,
 /* - */ CCLASS_OTHER,    /* . */ CCLASS_OTHER,   /* / */ CCLASS_OTHER,
 /* 0 */ CCLASS_DIGIT,    /* 1 */ CCLASS_DIGIT,   /* 2 */ CCLASS_DIGIT,
 /* 3 */ CCLASS_DIGIT,    /* 4 */ CCLASS_DIGIT,   /* 5 */ CCLASS_DIGIT,
 /* 6 */ CCLASS_DIGIT,    /* 7 */ CCLASS_DIGIT,   /* 8 */ CCLASS_DIGIT,
 /* 9 */ CCLASS_DIGIT,    /* : */ CCLASS_OTHER,   /* ; */ CCLASS_OTHER,
 /* < */ CCLASS_OTHER,    /* = */ CCLASS_OTHER,   /* > */ CCLASS_OTHER,
 /* ? */ CCLASS_OTHER,    /* @ */ CCLASS_OTHER,   /* A */ CCLASS_VOWEL,
 /* B */ CCLASS_B,        /* C */ CCLASS_C,       /* D */ CCLASS_D,
 /* E */ CCLASS_VOWEL,    /* F */ CCLASS_B,       /* G */ CCLASS_C,
 /* H */ CCLASS_SILENT,   /* I */ CCLASS_VOWEL,   /* J */ CCLASS_C,
 /* K */ CCLASS_C,        /* L */ CCLASS_L,       /* M */ CCLASS_M,
 /* N */ CCLASS_M,        /* O */ CCLASS_VOWEL,   /* P */ CCLASS_B,
 /* Q */ CCLASS_C,        /* R */ CCLASS_R,       /* S */ CCLASS_C,
 /* T */ CCLASS_D,        /* U */ CCLASS_VOWEL,   /* V */ CCLASS_B,
 /* W */ CCLASS_B,        /* X */ CCLASS_C,       /* Y */ CCLASS_Y,
 /* Z */ CCLASS_C,        /* [ */ CCLASS_OTHER,   /* \ */ CCLASS_OTHER,
 /* ] */ CCLASS_OTHER,    /* ^ */ CCLASS_OTHER,   /* _ */ CCLASS_OTHER,
 /* ` */ CCLASS_OTHER,    /* a */ CCLASS_VOWEL,   /* b */ CCLASS_B,
 /* c */ CCLASS_C,        /* d */ CCLASS_D,       /* e */ CCLASS_VOWEL,
 /* f */ CCLASS_B,        /* g */ CCLASS_C,       /* h */ CCLASS_SILENT,
 /* i */ CCLASS_VOWEL,    /* j */ CCLASS_C,       /* k */ CCLASS_C,
 /* l */ CCLASS_L,        /* m */ CCLASS_M,       /* n */ CCLASS_M,
 /* o */ CCLASS_VOWEL,    /* p */ CCLASS_B,       /* q */ CCLASS_C,
 /* r */ CCLASS_R,        /* s */ CCLASS_C,       /* t */ CCLASS_D,
 /* u */ CCLASS_VOWEL,    /* v */ CCLASS_B,       /* w */ CCLASS_B,
 /* x */ CCLASS_C,        /* y */ CCLASS_Y,       /* z */ CCLASS_C,
 /* { */ CCLASS_OTHER,    /* | */ CCLASS_OTHER,   /* } */ CCLASS_OTHER,
 /* ~ */ CCLASS_OTHER,    /*   */ CCLASS_OTHER,   
};

/*
** Mapping from the character class number (0-13) to a symbol for each
** character class.  Note that initClass[] can be used to map the class
** symbol back into the class number.
*/
static const unsigned char className[] = ".ABCDHLRMY9 ?";

/*
** Generate a "phonetic hash" from a string of ASCII characters
** in zIn[0..nIn-1].
**
**   * Map characters by character class as defined above.
**   * Omit double-letters
**   * Omit vowels beside R and L
**   * Omit T when followed by CH
**   * Omit W when followed by R
**   * Omit D when followed by J or G
**   * Omit K in KN or G in GN at the beginning of a word
**
** Space to hold the result is obtained from sqlite3_malloc()
**
** Return NULL if memory allocation fails.  
*/
static unsigned char *phoneticHash(const unsigned char *zIn, int nIn){
  unsigned char *zOut = sqlite3_malloc64( nIn + 1 );
  int i;
  int nOut = 0;
  char cPrev = 0x77;
  char cPrevX = 0x77;
  const unsigned char *aClass = initClass;

  if( zOut==0 ) return 0;
  if( nIn>2 ){
    switch( zIn[0] ){
      case 'g': 
      case 'k': {
        if( zIn[1]=='n' ){ zIn++; nIn--; }
        break;
      }
    }
  }
  for(i=0; i<nIn; i++){
    unsigned char c = zIn[i];
    if( i+1<nIn ){
      if( c=='w' && zIn[i+1]=='r' ) continue;
      if( c=='d' && (zIn[i+1]=='j' || zIn[i+1]=='g') ) continue;
      if( i+2<nIn ){
        if( c=='t' && zIn[i+1]=='c' && zIn[i+2]=='h' ) continue;
      }
    }
    c = aClass[c&0x7f];
    if( c==CCLASS_SPACE ) continue;
    if( c==CCLASS_OTHER && cPrev!=CCLASS_DIGIT ) continue;
    aClass = midClass;
    if( c==CCLASS_VOWEL && (cPrevX==CCLASS_R || cPrevX==CCLASS_L) ){
       continue; /* No vowels beside L or R */ 
    }
    if( (c==CCLASS_R || c==CCLASS_L) && cPrevX==CCLASS_VOWEL ){
       nOut--;   /* No vowels beside L or R */
    }
    cPrev = c;
    if( c==CCLASS_SILENT ) continue;
    cPrevX = c;
    c = className[c];
    assert( nOut>=0 );
    if( nOut==0 || c!=zOut[nOut-1] ) zOut[nOut++] = c;
  }
  zOut[nOut] = 0;
  return zOut;
}

/*
** This is an SQL function wrapper around phoneticHash().  See
** the description of phoneticHash() for additional information.
*/
static void phoneticHashSqlFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const unsigned char *zIn;
  unsigned char *zOut;

  zIn = sqlite3_value_text(argv[0]);
  if( zIn==0 ) return;
  zOut = phoneticHash(zIn, sqlite3_value_bytes(argv[0]));
  if( zOut==0 ){
    sqlite3_result_error_nomem(context);
  }else{
    sqlite3_result_text(context, (char*)zOut, -1, sqlite3_free);
  }
}

/*
** Return the character class number for a character given its
** context.
*/
static char characterClass(char cPrev, char c){
  return cPrev==0 ? initClass[c&0x7f] : midClass[c&0x7f];
}

/*
** Return the cost of inserting or deleting character c immediately
** following character cPrev.  If cPrev==0, that means c is the first
** character of the word.
*/
static int insertOrDeleteCost(char cPrev, char c, char cNext){
  char classC = characterClass(cPrev, c);
  char classCprev;

  if( classC==CCLASS_SILENT ){
    /* Insert or delete "silent" characters such as H or W */
    return 1;
  }
  if( cPrev==c ){
    /* Repeated characters, or miss a repeat */
    return 10;
  }
  if( classC==CCLASS_VOWEL && (cPrev=='r' || cNext=='r') ){
    return 20;  /* Insert a vowel before or after 'r' */
  }
  classCprev = characterClass(cPrev, cPrev);
  if( classC==classCprev ){
    if( classC==CCLASS_VOWEL ){
      /* Remove or add a new vowel to a vowel cluster */
      return 15;
    }else{
      /* Remove or add a consonant not in the same class */
      return 50;
    }
  }

  /* any other character insertion or deletion */
  return 100;
}

/*
** Divide the insertion cost by this factor when appending to the
** end of the word.
*/
#define FINAL_INS_COST_DIV  4

/*
** Return the cost of substituting cTo in place of cFrom assuming
** the previous character is cPrev.  If cPrev==0 then cTo is the first
** character of the word.
*/
static int substituteCost(char cPrev, char cFrom, char cTo){
  char classFrom, classTo;
  if( cFrom==cTo ){
    /* Exact match */
    return 0;
  }
  if( cFrom==(cTo^0x20) && ((cTo>='A' && cTo<='Z') || (cTo>='a' && cTo<='z')) ){
    /* differ only in case */
    return 0;
  }
  classFrom = characterClass(cPrev, cFrom);
  classTo = characterClass(cPrev, cTo);
  if( classFrom==classTo ){
    /* Same character class */
    return 40;
  }
  if( classFrom>=CCLASS_B && classFrom<=CCLASS_Y
      && classTo>=CCLASS_B && classTo<=CCLASS_Y ){
    /* Convert from one consonant to another, but in a different class */
    return 75;
  }
  /* Any other subsitution */
  return 100;
}

/*
** Given two strings zA and zB which are pure ASCII, return the cost
** of transforming zA into zB.  If zA ends with '*' assume that it is
** a prefix of zB and give only minimal penalty for extra characters
** on the end of zB.
**
** Smaller numbers mean a closer match.
**
** Negative values indicate an error:
**    -1  One of the inputs is NULL
**    -2  Non-ASCII characters on input
**    -3  Unable to allocate memory
**
** If pnMatch is not NULL, then *pnMatch is set to the number of bytes
** of zB that matched the pattern in zA. If zA does not end with a '*',
** then this value is always the number of bytes in zB (i.e. strlen(zB)).
** If zA does end in a '*', then it is the number of bytes in the prefix
** of zB that was deemed to match zA.
*/
static int editdist1(const char *zA, const char *zB, int *pnMatch){
  unsigned int nA, nB;   /* Number of characters in zA[] and zB[] */
  unsigned int xA, xB;   /* Loop counters for zA[] and zB[] */
  char cA = 0, cB;       /* Current character of zA and zB */
  char cAprev, cBprev;   /* Previous character of zA and zB */
  char cAnext, cBnext;   /* Next character in zA and zB */
  int d;                 /* North-west cost value */
  int dc = 0;            /* North-west character value */
  int res;               /* Final result */
  int *m;                /* The cost matrix */
  char *cx;              /* Corresponding character values */
  int *toFree = 0;       /* Malloced space */
  int nMatch = 0;
  int mStack[60+15];     /* Stack space to use if not too much is needed */

  /* Early out if either input is NULL */
  if( zA==0 || zB==0 ) return -1;

  /* Skip any common prefix */
  while( zA[0] && zA[0]==zB[0] ){ dc = zA[0]; zA++; zB++; nMatch++; }
  if( pnMatch ) *pnMatch = nMatch;
  if( zA[0]==0 && zB[0]==0 ) return 0;

#if 0
  printf("A=\"%s\" B=\"%s\" dc=%c\n", zA, zB, dc?dc:' ');
#endif

  /* Verify input strings and measure their lengths */
  for(nA=0; zA[nA]; nA++){
    if( zA[nA]&0x80 ) return -2;
  }
  for(nB=0; zB[nB]; nB++){
    if( zB[nB]&0x80 ) return -2;
  }

  /* Special processing if either string is empty */
  if( nA==0 ){
    cBprev = (char)dc;
    for(xB=res=0; (cB = zB[xB])!=0; xB++){
      res += insertOrDeleteCost(cBprev, cB, zB[xB+1])/FINAL_INS_COST_DIV;
      cBprev = cB;
    }
    return res;
  }
  if( nB==0 ){
    cAprev = (char)dc;
    for(xA=res=0; (cA = zA[xA])!=0; xA++){
      res += insertOrDeleteCost(cAprev, cA, zA[xA+1]);
      cAprev = cA;
    }
    return res;
  }

  /* A is a prefix of B */
  if( zA[0]=='*' && zA[1]==0 ) return 0;

  /* Allocate and initialize the Wagner matrix */
  if( nB<(sizeof(mStack)*4)/(sizeof(mStack[0])*5) ){
    m = mStack;
  }else{
    m = toFree = sqlite3_malloc64( (nB+1)*5*sizeof(m[0])/4 );
    if( m==0 ) return -3;
  }
  cx = (char*)&m[nB+1];

  /* Compute the Wagner edit distance */
  m[0] = 0;
  cx[0] = (char)dc;
  cBprev = (char)dc;
  for(xB=1; xB<=nB; xB++){
    cBnext = zB[xB];
    cB = zB[xB-1];
    cx[xB] = cB;
    m[xB] = m[xB-1] + insertOrDeleteCost(cBprev, cB, cBnext);
    cBprev = cB;
  }
  cAprev = (char)dc;
  for(xA=1; xA<=nA; xA++){
    int lastA = (xA==nA);
    cA = zA[xA-1];
    cAnext = zA[xA];
    if( cA=='*' && lastA ) break;
    d = m[0];
    dc = cx[0];
    m[0] = d + insertOrDeleteCost(cAprev, cA, cAnext);
    cBprev = 0;
    for(xB=1; xB<=nB; xB++){
      int totalCost, insCost, delCost, subCost, ncx;
      cB = zB[xB-1];
      cBnext = zB[xB];

      /* Cost to insert cB */
      insCost = insertOrDeleteCost(cx[xB-1], cB, cBnext);
      if( lastA ) insCost /= FINAL_INS_COST_DIV;

      /* Cost to delete cA */
      delCost = insertOrDeleteCost(cx[xB], cA, cBnext);

      /* Cost to substitute cA->cB */
      subCost = substituteCost(cx[xB-1], cA, cB);

      /* Best cost */
      totalCost = insCost + m[xB-1];
      ncx = cB;
      if( (delCost + m[xB])<totalCost ){
        totalCost = delCost + m[xB];
        ncx = cA;
      }
      if( (subCost + d)<totalCost ){
        totalCost = subCost + d;
      }

#if 0
      printf("%d,%d d=%4d u=%4d r=%4d dc=%c cA=%c cB=%c"
             " ins=%4d del=%4d sub=%4d t=%4d ncx=%c\n",
             xA, xB, d, m[xB], m[xB-1], dc?dc:' ', cA, cB,
             insCost, delCost, subCost, totalCost, ncx?ncx:' ');
#endif

      /* Update the matrix */
      d = m[xB];
      dc = cx[xB];
      m[xB] = totalCost;
      cx[xB] = (char)ncx;
      cBprev = cB;
    }
    cAprev = cA;
  }

  /* Free the wagner matrix and return the result */
  if( cA=='*' ){
    res = m[1];
    for(xB=1; xB<=nB; xB++){
      if( m[xB]<res ){
        res = m[xB];
        if( pnMatch ) *pnMatch = xB+nMatch;
      }
    }
  }else{
    res = m[nB];
    /* In the current implementation, pnMatch is always NULL if zA does
    ** not end in "*" */
    assert( pnMatch==0 );
  }
  sqlite3_free(toFree);
  return res;
}

/*
** Function:    editdist(A,B)
**
** Return the cost of transforming string A into string B.  Both strings
** must be pure ASCII text.  If A ends with '*' then it is assumed to be
** a prefix of B and extra characters on the end of B have minimal additional
** cost.
*/
static void editdistSqlFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  int res = editdist1(
                    (const char*)sqlite3_value_text(argv[0]),
                    (const char*)sqlite3_value_text(argv[1]),
                    0);
  if( res<0 ){
    if( res==(-3) ){
      sqlite3_result_error_nomem(context);
    }else if( res==(-2) ){
      sqlite3_result_error(context, "non-ASCII input to editdist()", -1);
    }else{
      sqlite3_result_error(context, "NULL input to editdist()", -1);
    }
  }else{ 
    sqlite3_result_int(context, res);
  }
}

/* End of the fixed-cost edit distance implementation
******************************************************************************
*****************************************************************************
** Begin: Configurable cost unicode edit distance routines
*/
/* Forward declaration of structures */
typedef struct EditDist3Cost EditDist3Cost;
typedef struct EditDist3Config EditDist3Config;
typedef struct EditDist3Point EditDist3Point;
typedef struct EditDist3From EditDist3From;
typedef struct EditDist3FromString EditDist3FromString;
typedef struct EditDist3To EditDist3To;
typedef struct EditDist3ToString EditDist3ToString;
typedef struct EditDist3Lang EditDist3Lang;


/*
** An entry in the edit cost table
*/
struct EditDist3Cost {
  EditDist3Cost *pNext;     /* Next cost element */
  u8 nFrom;                 /* Number of bytes in aFrom */
  u8 nTo;                   /* Number of bytes in aTo */
  u16 iCost;                /* Cost of this transformation */
  char a[4]    ;            /* FROM string followed by TO string */
  /* Additional TO and FROM string bytes appended as necessary */
};

/*
** Edit costs for a particular language ID 
*/
struct EditDist3Lang {
  int iLang;             /* Language ID */
  int iInsCost;          /* Default insertion cost */
  int iDelCost;          /* Default deletion cost */
  int iSubCost;          /* Default substitution cost */
  EditDist3Cost *pCost;  /* Costs */
};


/*
** The default EditDist3Lang object, with default costs.
*/
static const EditDist3Lang editDist3Lang = { 0, 100, 100, 150, 0 };

/*
** Complete configuration
*/
struct EditDist3Config {
  int nLang;             /* Number of language IDs.  Size of a[] */
  EditDist3Lang *a;      /* One for each distinct language ID */
};

/*
** Extra information about each character in the FROM string.
*/
struct EditDist3From {
  int nSubst;              /* Number of substitution cost entries */
  int nDel;                /* Number of deletion cost entries */
  int nByte;               /* Number of bytes in this character */
  EditDist3Cost **apSubst; /* Array of substitution costs for this element */
  EditDist3Cost **apDel;   /* Array of deletion cost entries */
};

/*
** A precompiled FROM string.
*
** In the common case we expect the FROM string to be reused multiple times.
** In other words, the common case will be to measure the edit distance
** from a single origin string to multiple target strings.
*/
struct EditDist3FromString {
  char *z;                 /* The complete text of the FROM string */
  int n;                   /* Number of characters in the FROM string */
  int isPrefix;            /* True if ends with '*' character */
  EditDist3From *a;        /* Extra info about each char of the FROM string */
};

/*
** Extra information about each character in the TO string.
*/
struct EditDist3To {
  int nIns;                /* Number of insertion cost entries */
  int nByte;               /* Number of bytes in this character */
  EditDist3Cost **apIns;   /* Array of deletion cost entries */
};

/*
** A precompiled FROM string
*/
struct EditDist3ToString {
  char *z;                 /* The complete text of the TO string */
  int n;                   /* Number of characters in the TO string */
  EditDist3To *a;          /* Extra info about each char of the TO string */
};

/*
** Clear or delete an instance of the object that records all edit-distance
** weights.
*/
static void editDist3ConfigClear(EditDist3Config *p){
  int i;
  if( p==0 ) return;
  for(i=0; i<p->nLang; i++){
    EditDist3Cost *pCost, *pNext;
    pCost = p->a[i].pCost;
    while( pCost ){
      pNext = pCost->pNext;
      sqlite3_free(pCost);
      pCost = pNext;
    }
  }
  sqlite3_free(p->a);
  memset(p, 0, sizeof(*p));
}
static void editDist3ConfigDelete(void *pIn){
  EditDist3Config *p = (EditDist3Config*)pIn;
  editDist3ConfigClear(p);
  sqlite3_free(p);
}

/* Compare the FROM values of two EditDist3Cost objects, for sorting.
** Return negative, zero, or positive if the A is less than, equal to,
** or greater than B.
*/
static int editDist3CostCompare(EditDist3Cost *pA, EditDist3Cost *pB){
  int n = pA->nFrom;
  int rc;
  if( n>pB->nFrom ) n = pB->nFrom;
  rc = strncmp(pA->a, pB->a, n);
  if( rc==0 ) rc = pA->nFrom - pB->nFrom;
  return rc;
}

/*
** Merge together two sorted lists of EditDist3Cost objects, in order
** of increasing FROM.
*/
static EditDist3Cost *editDist3CostMerge(
  EditDist3Cost *pA,
  EditDist3Cost *pB
){
  EditDist3Cost *pHead = 0;
  EditDist3Cost **ppTail = &pHead;
  EditDist3Cost *p;
  while( pA && pB ){
    if( editDist3CostCompare(pA,pB)<=0 ){
      p = pA;
      pA = pA->pNext;
    }else{
      p = pB;
      pB = pB->pNext;
    }
    *ppTail = p;
    ppTail =  &p->pNext;
  }
  if( pA ){
    *ppTail = pA;
  }else{
    *ppTail = pB;
  }
  return pHead;
}

/*
** Sort a list of EditDist3Cost objects into order of increasing FROM
*/
static EditDist3Cost *editDist3CostSort(EditDist3Cost *pList){
  EditDist3Cost *ap[60], *p;
  int i;
  int mx = 0;
  ap[0] = 0;
  ap[1] = 0;
  while( pList ){
    p = pList;
    pList = p->pNext;
    p->pNext = 0;
    for(i=0; ap[i]; i++){
      p = editDist3CostMerge(ap[i],p);
      ap[i] = 0;
    }
    ap[i] = p;
    if( i>mx ){
      mx = i;
      ap[i+1] = 0;
    }
  }
  p = 0;
  for(i=0; i<=mx; i++){
    if( ap[i] ) p = editDist3CostMerge(p,ap[i]);
  }
  return p;
}

/*
** Load all edit-distance weights from a table.
*/
static int editDist3ConfigLoad(
  EditDist3Config *p,      /* The edit distance configuration to load */
  sqlite3 *db,            /* Load from this database */
  const char *zTable      /* Name of the table from which to load */
){
  sqlite3_stmt *pStmt;
  int rc, rc2;
  char *zSql;
  int iLangPrev = -9999;
  EditDist3Lang *pLang = 0;

  zSql = sqlite3_mprintf("SELECT iLang, cFrom, cTo, iCost"
                         " FROM \"%w\" WHERE iLang>=0 ORDER BY iLang", zTable);
  if( zSql==0 ) return SQLITE_NOMEM;
  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
  sqlite3_free(zSql);
  if( rc ) return rc;
  editDist3ConfigClear(p);
  while( sqlite3_step(pStmt)==SQLITE_ROW ){
    int iLang = sqlite3_column_int(pStmt, 0);
    const char *zFrom = (const char*)sqlite3_column_text(pStmt, 1);
    int nFrom = zFrom ? sqlite3_column_bytes(pStmt, 1) : 0;
    const char *zTo = (const char*)sqlite3_column_text(pStmt, 2);
    int nTo = zTo ? sqlite3_column_bytes(pStmt, 2) : 0;
    int iCost = sqlite3_column_int(pStmt, 3);

    assert( zFrom!=0 || nFrom==0 );
    assert( zTo!=0 || nTo==0 );
    if( nFrom>100 || nTo>100 ) continue;
    if( iCost<0 ) continue;
    if( iCost>=10000 ) continue;  /* Costs above 10K are considered infinite */
    if( pLang==0 || iLang!=iLangPrev ){
      EditDist3Lang *pNew;
      pNew = sqlite3_realloc64(p->a, (p->nLang+1)*sizeof(p->a[0]));
      if( pNew==0 ){ rc = SQLITE_NOMEM; break; }
      p->a = pNew;
      pLang = &p->a[p->nLang];
      p->nLang++;
      pLang->iLang = iLang;
      pLang->iInsCost = 100;
      pLang->iDelCost = 100;
      pLang->iSubCost = 150;
      pLang->pCost = 0;
      iLangPrev = iLang;
    }
    if( nFrom==1 && zFrom[0]=='?' && nTo==0 ){
      pLang->iDelCost = iCost;
    }else if( nFrom==0 && nTo==1 && zTo[0]=='?' ){
      pLang->iInsCost = iCost;
    }else if( nFrom==1 && nTo==1 && zFrom[0]=='?' && zTo[0]=='?' ){
      pLang->iSubCost = iCost;
    }else{
      EditDist3Cost *pCost;
      int nExtra = nFrom + nTo - 4;
      if( nExtra<0 ) nExtra = 0;
      pCost = sqlite3_malloc64( sizeof(*pCost) + nExtra );
      if( pCost==0 ){ rc = SQLITE_NOMEM; break; }
      pCost->nFrom = (u8)nFrom;
      pCost->nTo = (u8)nTo;
      pCost->iCost = (u16)iCost;
      memcpy(pCost->a, zFrom, nFrom);
      memcpy(pCost->a + nFrom, zTo, nTo);
      pCost->pNext = pLang->pCost;
      pLang->pCost = pCost; 
    }
  }
  rc2 = sqlite3_finalize(pStmt);
  if( rc==SQLITE_OK ) rc = rc2;
  if( rc==SQLITE_OK ){
    int iLang;
    for(iLang=0; iLang<p->nLang; iLang++){
      p->a[iLang].pCost = editDist3CostSort(p->a[iLang].pCost);
    }
  }
  return rc;
}

/*
** Return the length (in bytes) of a utf-8 character.  Or return a maximum
** of N.
*/
static int utf8Len(unsigned char c, int N){
  int len = 1;
  if( c>0x7f ){
    if( (c&0xe0)==0xc0 ){
      len = 2;
    }else if( (c&0xf0)==0xe0 ){
      len = 3;
    }else{
      len = 4;
    }
  }
  if( len>N ) len = N;
  return len;
}

/*
** Return TRUE (non-zero) if the To side of the given cost matches
** the given string.
*/
static int matchTo(EditDist3Cost *p, const char *z, int n){
  assert( n>0 );
  if( p->a[p->nFrom]!=z[0] ) return 0;
  if( p->nTo>n ) return 0;
  if( strncmp(p->a+p->nFrom, z, p->nTo)!=0 ) return 0;
  return 1;
}

/*
** Return TRUE (non-zero) if the From side of the given cost matches
** the given string.
*/
static int matchFrom(EditDist3Cost *p, const char *z, int n){
  assert( p->nFrom<=n );
  if( p->nFrom ){
    if( p->a[0]!=z[0] ) return 0;
    if( strncmp(p->a, z, p->nFrom)!=0 ) return 0;
  }
  return 1;
}

/*
** Return TRUE (non-zero) of the next FROM character and the next TO
** character are the same.
*/
static int matchFromTo(
  EditDist3FromString *pStr,  /* Left hand string */
  int n1,                     /* Index of comparison character on the left */
  const char *z2,             /* Right-handl comparison character */
  int n2                      /* Bytes remaining in z2[] */
){
  int b1 = pStr->a[n1].nByte;
  if( b1>n2 ) return 0;
  assert( b1>0 );
  if( pStr->z[n1]!=z2[0] ) return 0;
  if( strncmp(pStr->z+n1, z2, b1)!=0 ) return 0;
  return 1;
}

/*
** Delete an EditDist3FromString objecct
*/
static void editDist3FromStringDelete(EditDist3FromString *p){
  int i;
  if( p ){
    for(i=0; i<p->n; i++){
      sqlite3_free(p->a[i].apDel);
      sqlite3_free(p->a[i].apSubst);
    }
    sqlite3_free(p);
  }
}

/*
** Create a EditDist3FromString object.
*/
static EditDist3FromString *editDist3FromStringNew(
  const EditDist3Lang *pLang,
  const char *z,
  int n
){
  EditDist3FromString *pStr;
  EditDist3Cost *p;
  int i;

  if( z==0 ) return 0;
  if( n<0 ) n = (int)strlen(z);
  pStr = sqlite3_malloc64( sizeof(*pStr) + sizeof(pStr->a[0])*n + n + 1 );
  if( pStr==0 ) return 0;
  pStr->a = (EditDist3From*)&pStr[1];
  memset(pStr->a, 0, sizeof(pStr->a[0])*n);
  pStr->n = n;
  pStr->z = (char*)&pStr->a[n];
  memcpy(pStr->z, z, n+1);
  if( n && z[n-1]=='*' ){
    pStr->isPrefix = 1;
    n--;
    pStr->n--;
    pStr->z[n] = 0;
  }else{
    pStr->isPrefix = 0;
  }

  for(i=0; i<n; i++){
    EditDist3From *pFrom = &pStr->a[i];
    memset(pFrom, 0, sizeof(*pFrom));
    pFrom->nByte = utf8Len((unsigned char)z[i], n-i);
    for(p=pLang->pCost; p; p=p->pNext){
      EditDist3Cost **apNew;
      if( i+p->nFrom>n ) continue;
      if( matchFrom(p, z+i, n-i)==0 ) continue;
      if( p->nTo==0 ){
        apNew = sqlite3_realloc64(pFrom->apDel,
                                sizeof(*apNew)*(pFrom->nDel+1));
        if( apNew==0 ) break;
        pFrom->apDel = apNew;
        apNew[pFrom->nDel++] = p;
      }else{
        apNew = sqlite3_realloc64(pFrom->apSubst,
                                sizeof(*apNew)*(pFrom->nSubst+1));
        if( apNew==0 ) break;
        pFrom->apSubst = apNew;
        apNew[pFrom->nSubst++] = p;
      }
    }
    if( p ){
      editDist3FromStringDelete(pStr);
      pStr = 0;
      break;
    }
  }
  return pStr;
}

/*
** Update entry m[i] such that it is the minimum of its current value
** and m[j]+iCost.
*/
static void updateCost(
  unsigned int *m,
  int i,
  int j,
  int iCost
){
  unsigned int b;
  assert( iCost>=0 );
  assert( iCost<10000 );
  b = m[j] + iCost;
  if( b<m[i] ) m[i] = b;
}

/*
** How much stack space (int bytes) to use for Wagner matrix in 
** editDist3Core().  If more space than this is required, the entire
** matrix is taken from the heap.  To reduce the load on the memory
** allocator, make this value as large as practical for the
** architecture in use.
*/
#ifndef SQLITE_SPELLFIX_STACKALLOC_SZ
# define SQLITE_SPELLFIX_STACKALLOC_SZ  (1024)
#endif

/* Compute the edit distance between two strings.
**
** If an error occurs, return a negative number which is the error code.
**
** If pnMatch is not NULL, then *pnMatch is set to the number of characters
** (not bytes) in z2 that matched the search pattern in *pFrom. If pFrom does
** not contain the pattern for a prefix-search, then this is always the number
** of characters in z2. If pFrom does contain a prefix search pattern, then
** it is the number of characters in the prefix of z2 that was deemed to 
** match pFrom.
*/
static int editDist3Core(
  EditDist3FromString *pFrom,  /* The FROM string */
  const char *z2,              /* The TO string */
  int n2,                      /* Length of the TO string */
  const EditDist3Lang *pLang,  /* Edit weights for a particular language ID */
  int *pnMatch                 /* OUT: Characters in matched prefix */
){
  int k, n;
  int i1, b1;
  int i2, b2;
  EditDist3FromString f = *pFrom;
  EditDist3To *a2;
  unsigned int *m;
  unsigned int *pToFree;
  int szRow;
  EditDist3Cost *p;
  int res;
  sqlite3_uint64 nByte;
  unsigned int stackSpace[SQLITE_SPELLFIX_STACKALLOC_SZ/sizeof(unsigned int)];

  /* allocate the Wagner matrix and the aTo[] array for the TO string */
  n = (f.n+1)*(n2+1);
  n = (n+1)&~1;
  nByte = n*sizeof(m[0]) + sizeof(a2[0])*n2;
  if( nByte<=sizeof(stackSpace) ){
    m = stackSpace;
    pToFree = 0;
  }else{
    m = pToFree = sqlite3_malloc64( nByte );
    if( m==0 ) return -1;            /* Out of memory */
  }
  a2 = (EditDist3To*)&m[n];
  memset(a2, 0, sizeof(a2[0])*n2);

  /* Fill in the a1[] matrix for all characters of the TO string */
  for(i2=0; i2<n2; i2++){
    a2[i2].nByte = utf8Len((unsigned char)z2[i2], n2-i2);
    for(p=pLang->pCost; p; p=p->pNext){
      EditDist3Cost **apNew;
      if( p->nFrom>0 ) break;
      if( i2+p->nTo>n2 ) continue;
      if( p->a[0]>z2[i2] ) break;
      if( matchTo(p, z2+i2, n2-i2)==0 ) continue;
      a2[i2].nIns++;
      apNew = sqlite3_realloc64(a2[i2].apIns, sizeof(*apNew)*a2[i2].nIns);
      if( apNew==0 ){
        res = -1;  /* Out of memory */
        goto editDist3Abort;
      }
      a2[i2].apIns = apNew;
      a2[i2].apIns[a2[i2].nIns-1] = p;
    }
  }

  /* Prepare to compute the minimum edit distance */
  szRow = f.n+1;
  memset(m, 0x01, (n2+1)*szRow*sizeof(m[0]));
  m[0] = 0;

  /* First fill in the top-row of the matrix with FROM deletion costs */
  for(i1=0; i1<f.n; i1 += b1){
    b1 = f.a[i1].nByte;
    updateCost(m, i1+b1, i1, pLang->iDelCost);
    for(k=0; k<f.a[i1].nDel; k++){
      p = f.a[i1].apDel[k];
      updateCost(m, i1+p->nFrom, i1, p->iCost);
    }
  }

  /* Fill in all subsequent rows, top-to-bottom, left-to-right */
  for(i2=0; i2<n2; i2 += b2){
    int rx;      /* Starting index for current row */
    int rxp;     /* Starting index for previous row */
    b2 = a2[i2].nByte;
    rx = szRow*(i2+b2);
    rxp = szRow*i2;
    updateCost(m, rx, rxp, pLang->iInsCost);
    for(k=0; k<a2[i2].nIns; k++){
      p = a2[i2].apIns[k];
      updateCost(m, szRow*(i2+p->nTo), rxp, p->iCost);
    }
    for(i1=0; i1<f.n; i1+=b1){
      int cx;    /* Index of current cell */
      int cxp;   /* Index of cell immediately to the left */
      int cxd;   /* Index of cell to the left and one row above */
      int cxu;   /* Index of cell immediately above */
      b1 = f.a[i1].nByte;
      cxp = rx + i1;
      cx = cxp + b1;
      cxd = rxp + i1;
      cxu = cxd + b1;
      updateCost(m, cx, cxp, pLang->iDelCost);
      for(k=0; k<f.a[i1].nDel; k++){
        p = f.a[i1].apDel[k];
        updateCost(m, cxp+p->nFrom, cxp, p->iCost);
      }
      updateCost(m, cx, cxu, pLang->iInsCost);
      if( matchFromTo(&f, i1, z2+i2, n2-i2) ){
        updateCost(m, cx, cxd, 0);
      }
      updateCost(m, cx, cxd, pLang->iSubCost);
      for(k=0; k<f.a[i1].nSubst; k++){
        p = f.a[i1].apSubst[k];
        if( matchTo(p, z2+i2, n2-i2) ){
          updateCost(m, cxd+p->nFrom+szRow*p->nTo, cxd, p->iCost);
        }
      }
    }
  }

#if 0  /* Enable for debugging */
  printf("         ^");
  for(i1=0; i1<f.n; i1++) printf(" %c-%2x", f.z[i1], f.z[i1]&0xff);
  printf("\n   ^:");
  for(i1=0; i1<szRow; i1++){
    int v = m[i1];
    if( v>9999 ) printf(" ****");
    else         printf(" %4d", v);
  }
  printf("\n");
  for(i2=0; i2<n2; i2++){
    printf("%c-%02x:", z2[i2], z2[i2]&0xff);
    for(i1=0; i1<szRow; i1++){
      int v = m[(i2+1)*szRow+i1];
      if( v>9999 ) printf(" ****");
      else         printf(" %4d", v);
    }
    printf("\n");
  }
#endif

  /* Free memory allocations and return the result */
  res = (int)m[szRow*(n2+1)-1];
  n = n2;
  if( f.isPrefix ){
    for(i2=1; i2<=n2; i2++){
      int b = m[szRow*i2-1];
      if( b<=res ){ 
        res = b;
        n = i2 - 1;
      }
    }
  }
  if( pnMatch ){
    int nExtra = 0;
    for(k=0; k<n; k++){
      if( (z2[k] & 0xc0)==0x80 ) nExtra++;
    }
    *pnMatch = n - nExtra;
  }

editDist3Abort:
  for(i2=0; i2<n2; i2++) sqlite3_free(a2[i2].apIns);
  sqlite3_free(pToFree);
  return res;
}

/*
** Get an appropriate EditDist3Lang object.
*/
static const EditDist3Lang *editDist3FindLang(
  EditDist3Config *pConfig,
  int iLang
){
  int i;
  for(i=0; i<pConfig->nLang; i++){
    if( pConfig->a[i].iLang==iLang ) return &pConfig->a[i];
  }
  return &editDist3Lang;
}

/*
** Function:    editdist3(A,B,iLang)
**              editdist3(tablename)
**
** Return the cost of transforming string A into string B using edit
** weights for iLang.
**
** The second form loads edit weights into memory from a table.
*/
static void editDist3SqlFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  EditDist3Config *pConfig = (EditDist3Config*)sqlite3_user_data(context);
  sqlite3 *db = sqlite3_context_db_handle(context);
  int rc;
  if( argc==1 ){
    const char *zTable = (const char*)sqlite3_value_text(argv[0]);
    rc = editDist3ConfigLoad(pConfig, db, zTable);
    if( rc ) sqlite3_result_error_code(context, rc);
  }else{
    const char *zA = (const char*)sqlite3_value_text(argv[0]);
    const char *zB = (const char*)sqlite3_value_text(argv[1]);
    int nA = sqlite3_value_bytes(argv[0]);
    int nB = sqlite3_value_bytes(argv[1]);
    int iLang = argc==3 ? sqlite3_value_int(argv[2]) : 0;
    const EditDist3Lang *pLang = editDist3FindLang(pConfig, iLang);
    EditDist3FromString *pFrom;
    int dist;

    pFrom = editDist3FromStringNew(pLang, zA, nA);
    if( pFrom==0 ){
      sqlite3_result_error_nomem(context);
      return;
    }
    dist = editDist3Core(pFrom, zB, nB, pLang, 0);
    editDist3FromStringDelete(pFrom);
    if( dist==(-1) ){
      sqlite3_result_error_nomem(context);
    }else{
      sqlite3_result_int(context, dist);
    }
  } 
}

/*
** Register the editDist3 function with SQLite
*/
static int editDist3Install(sqlite3 *db){
  int rc;
  EditDist3Config *pConfig = sqlite3_malloc64( sizeof(*pConfig) );
  if( pConfig==0 ) return SQLITE_NOMEM;
  memset(pConfig, 0, sizeof(*pConfig));
  rc = sqlite3_create_function_v2(db, "editdist3",
              2, SQLITE_UTF8|SQLITE_DETERMINISTIC, pConfig,
              editDist3SqlFunc, 0, 0, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function_v2(db, "editdist3",
                3, SQLITE_UTF8|SQLITE_DETERMINISTIC, pConfig,
                editDist3SqlFunc, 0, 0, 0);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function_v2(db, "editdist3",
                1, SQLITE_UTF8|SQLITE_DETERMINISTIC, pConfig,
                editDist3SqlFunc, 0, 0, editDist3ConfigDelete);
  }else{
    sqlite3_free(pConfig);
  }
  return rc;
}
/* End configurable cost unicode edit distance routines
******************************************************************************
******************************************************************************
** Begin transliterate unicode-to-ascii implementation
*/

#if !SQLITE_AMALGAMATION
/*
** This lookup table is used to help decode the first byte of
** a multi-byte UTF8 character.
*/
static const unsigned char sqlite3Utf8Trans1[] = {
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
};
#endif

/*
** Return the value of the first UTF-8 character in the string.
*/
static int utf8Read(const unsigned char *z, int n, int *pSize){
  int c, i;

  /* All callers to this routine (in the current implementation)
  ** always have n>0. */
  if( NEVER(n==0) ){
    c = i = 0;
  }else{
    c = z[0];
    i = 1;
    if( c>=0xc0 ){
      c = sqlite3Utf8Trans1[c-0xc0];
      while( i<n && (z[i] & 0xc0)==0x80 ){
        c = (c<<6) + (0x3f & z[i++]);
      }
    }
  }
  *pSize = i;
  return c;
}

/*
** Return the number of characters in the utf-8 string in the nIn byte
** buffer pointed to by zIn.
*/
static int utf8Charlen(const char *zIn, int nIn){
  int i;
  int nChar = 0;
  for(i=0; i<nIn; nChar++){
    int sz;
    utf8Read((const unsigned char *)&zIn[i], nIn-i, &sz);
    i += sz;
  }
  return nChar;
}

typedef struct Transliteration Transliteration;
struct Transliteration {
 unsigned short int cFrom;
 unsigned char cTo0, cTo1, cTo2, cTo3;
#ifdef SQLITE_SPELLFIX_5BYTE_MAPPINGS
 unsigned char cTo4;
#endif
};

/*
** Table of translations from unicode characters into ASCII.
*/
static const Transliteration translit[] = {
  { 0x00A0,  0x20, 0x00, 0x00, 0x00 },  /*   to   */
  { 0x00B5,  0x75, 0x00, 0x00, 0x00 },  /* µ to u */
  { 0x00C0,  0x41, 0x00, 0x00, 0x00 },  /* À to A */
  { 0x00C1,  0x41, 0x00, 0x00, 0x00 },  /* Á to A */
  { 0x00C2,  0x41, 0x00, 0x00, 0x00 },  /* Â to A */
  { 0x00C3,  0x41, 0x00, 0x00, 0x00 },  /* Ã to A */
  { 0x00C4,  0x41, 0x65, 0x00, 0x00 },  /* Ä to Ae */
  { 0x00C5,  0x41, 0x61, 0x00, 0x00 },  /* Å to Aa */
  { 0x00C6,  0x41, 0x45, 0x00, 0x00 },  /* Æ to AE */
  { 0x00C7,  0x43, 0x00, 0x00, 0x00 },  /* Ç to C */
  { 0x00C8,  0x45, 0x00, 0x00, 0x00 },  /* È to E */
  { 0x00C9,  0x45, 0x00, 0x00, 0x00 },  /* É to E */
  { 0x00CA,  0x45, 0x00, 0x00, 0x00 },  /* Ê to E */
  { 0x00CB,  0x45, 0x00, 0x00, 0x00 },  /* Ë to E */
  { 0x00CC,  0x49, 0x00, 0x00, 0x00 },  /* Ì to I */
  { 0x00CD,  0x49, 0x00, 0x00, 0x00 },  /* Í to I */
  { 0x00CE,  0x49, 0x00, 0x00, 0x00 },  /* Î to I */
  { 0x00CF,  0x49, 0x00, 0x00, 0x00 },  /* Ï to I */
  { 0x00D0,  0x44, 0x00, 0x00, 0x00 },  /* Ð to D */
  { 0x00D1,  0x4E, 0x00, 0x00, 0x00 },  /* Ñ to N */
  { 0x00D2,  0x4F, 0x00, 0x00, 0x00 },  /* Ò to O */
  { 0x00D3,  0x4F, 0x00, 0x00, 0x00 },  /* Ó to O */
  { 0x00D4,  0x4F, 0x00, 0x00, 0x00 },  /* Ô to O */
  { 0x00D5,  0x4F, 0x00, 0x00, 0x00 },  /* Õ to O */
  { 0x00D6,  0x4F, 0x65, 0x00, 0x00 },  /* Ö to Oe */
  { 0x00D7,  0x78, 0x00, 0x00, 0x00 },  /* × to x */
  { 0x00D8,  0x4F, 0x00, 0x00, 0x00 },  /* Ø to O */
  { 0x00D9,  0x55, 0x00, 0x00, 0x00 },  /* Ù to U */
  { 0x00DA,  0x55, 0x00, 0x00, 0x00 },  /* Ú to U */
  { 0x00DB,  0x55, 0x00, 0x00, 0x00 },  /* Û to U */
  { 0x00DC,  0x55, 0x65, 0x00, 0x00 },  /* Ü to Ue */
  { 0x00DD,  0x59, 0x00, 0x00, 0x00 },  /* Ý to Y */
  { 0x00DE,  0x54, 0x68, 0x00, 0x00 },  /* Þ to Th */
  { 0x00DF,  0x73, 0x73, 0x00, 0x00 },  /* ß to ss */
  { 0x00E0,  0x61, 0x00, 0x00, 0x00 },  /* à to a */
  { 0x00E1,  0x61, 0x00, 0x00, 0x00 },  /* á to a */
  { 0x00E2,  0x61, 0x00, 0x00, 0x00 },  /* â to a */
  { 0x00E3,  0x61, 0x00, 0x00, 0x00 },  /* ã to a */
  { 0x00E4,  0x61, 0x65, 0x00, 0x00 },  /* ä to ae */
  { 0x00E5,  0x61, 0x61, 0x00, 0x00 },  /* å to aa */
  { 0x00E6,  0x61, 0x65, 0x00, 0x00 },  /* æ to ae */
  { 0x00E7,  0x63, 0x00, 0x00, 0x00 },  /* ç to c */
  { 0x00E8,  0x65, 0x00, 0x00, 0x00 },  /* è to e */
  { 0x00E9,  0x65, 0x00, 0x00, 0x00 },  /* é to e */
  { 0x00EA,  0x65, 0x00, 0x00, 0x00 },  /* ê to e */
  { 0x00EB,  0x65, 0x00, 0x00, 0x00 },  /* ë to e */
  { 0x00EC,  0x69, 0x00, 0x00, 0x00 },  /* ì to i */
  { 0x00ED,  0x69, 0x00, 0x00, 0x00 },  /* í to i */
  { 0x00EE,  0x69, 0x00, 0x00, 0x00 },  /* î to i */
  { 0x00EF,  0x69, 0x00, 0x00, 0x00 },  /* ï to i */
  { 0x00F0,  0x64, 0x00, 0x00, 0x00 },  /* ð to d */
  { 0x00F1,  0x6E, 0x00, 0x00, 0x00 },  /* ñ to n */
  { 0x00F2,  0x6F, 0x00, 0x00, 0x00 },  /* ò to o */
  { 0x00F3,  0x6F, 0x00, 0x00, 0x00 },  /* ó to o */
  { 0x00F4,  0x6F, 0x00, 0x00, 0x00 },  /* ô to o */
  { 0x00F5,  0x6F, 0x00, 0x00, 0x00 },  /* õ to o */
  { 0x00F6,  0x6F, 0x65, 0x00, 0x00 },  /* ö to oe */
  { 0x00F7,  0x3A, 0x00, 0x00, 0x00 },  /* ÷ to : */
  { 0x00F8,  0x6F, 0x00, 0x00, 0x00 },  /* ø to o */
  { 0x00F9,  0x75, 0x00, 0x00, 0x00 },  /* ù to u */
  { 0x00FA,  0x75, 0x00, 0x00, 0x00 },  /* ú to u */
  { 0x00FB,  0x75, 0x00, 0x00, 0x00 },  /* û to u */
  { 0x00FC,  0x75, 0x65, 0x00, 0x00 },  /* ü to ue */
  { 0x00FD,  0x79, 0x00, 0x00, 0x00 },  /* ý to y */
  { 0x00FE,  0x74, 0x68, 0x00, 0x00 },  /* þ to th */
  { 0x00FF,  0x79, 0x00, 0x00, 0x00 },  /* ÿ to y */
  { 0x0100,  0x41, 0x00, 0x00, 0x00 },  /* Ā to A */
  { 0x0101,  0x61, 0x00, 0x00, 0x00 },  /* ā to a */
  { 0x0102,  0x41, 0x00, 0x00, 0x00 },  /* Ă to A */
  { 0x0103,  0x61, 0x00, 0x00, 0x00 },  /* ă to a */
  { 0x0104,  0x41, 0x00, 0x00, 0x00 },  /* Ą to A */
  { 0x0105,  0x61, 0x00, 0x00, 0x00 },  /* ą to a */
  { 0x0106,  0x43, 0x00, 0x00, 0x00 },  /* Ć to C */
  { 0x0107,  0x63, 0x00, 0x00, 0x00 },  /* ć to c */
  { 0x0108,  0x43, 0x68, 0x00, 0x00 },  /* Ĉ to Ch */
  { 0x0109,  0x63, 0x68, 0x00, 0x00 },  /* ĉ to ch */
  { 0x010A,  0x43, 0x00, 0x00, 0x00 },  /* Ċ to C */
  { 0x010B,  0x63, 0x00, 0x00, 0x00 },  /* ċ to c */
  { 0x010C,  0x43, 0x00, 0x00, 0x00 },  /* Č to C */
  { 0x010D,  0x63, 0x00, 0x00, 0x00 },  /* č to c */
  { 0x010E,  0x44, 0x00, 0x00, 0x00 },  /* Ď to D */
  { 0x010F,  0x64, 0x00, 0x00, 0x00 },  /* ď to d */
  { 0x0110,  0x44, 0x00, 0x00, 0x00 },  /* Đ to D */
  { 0x0111,  0x64, 0x00, 0x00, 0x00 },  /* đ to d */
  { 0x0112,  0x45, 0x00, 0x00, 0x00 },  /* Ē to E */
  { 0x0113,  0x65, 0x00, 0x00, 0x00 },  /* ē to e */
  { 0x0114,  0x45, 0x00, 0x00, 0x00 },  /* Ĕ to E */
  { 0x0115,  0x65, 0x00, 0x00, 0x00 },  /* ĕ to e */
  { 0x0116,  0x45, 0x00, 0x00, 0x00 },  /* Ė to E */
  { 0x0117,  0x65, 0x00, 0x00, 0x00 },  /* ė to e */
  { 0x0118,  0x45, 0x00, 0x00, 0x00 },  /* Ę to E */
  { 0x0119,  0x65, 0x00, 0x00, 0x00 },  /* ę to e */
  { 0x011A,  0x45, 0x00, 0x00, 0x00 },  /* Ě to E */
  { 0x011B,  0x65, 0x00, 0x00, 0x00 },  /* ě to e */
  { 0x011C,  0x47, 0x68, 0x00, 0x00 },  /* Ĝ to Gh */
  { 0x011D,  0x67, 0x68, 0x00, 0x00 },  /* ĝ to gh */
  { 0x011E,  0x47, 0x00, 0x00, 0x00 },  /* Ğ to G */
  { 0x011F,  0x67, 0x00, 0x00, 0x00 },  /* ğ to g */
  { 0x0120,  0x47, 0x00, 0x00, 0x00 },  /* Ġ to G */
  { 0x0121,  0x67, 0x00, 0x00, 0x00 },  /* ġ to g */
  { 0x0122,  0x47, 0x00, 0x00, 0x00 },  /* Ģ to G */
  { 0x0123,  0x67, 0x00, 0x00, 0x00 },  /* ģ to g */
  { 0x0124,  0x48, 0x68, 0x00, 0x00 },  /* Ĥ to Hh */
  { 0x0125,  0x68, 0x68, 0x00, 0x00 },  /* ĥ to hh */
  { 0x0126,  0x48, 0x00, 0x00, 0x00 },  /* Ħ to H */
  { 0x0127,  0x68, 0x00, 0x00, 0x00 },  /* ħ to h */
  { 0x0128,  0x49, 0x00, 0x00, 0x00 },  /* Ĩ to I */
  { 0x0129,  0x69, 0x00, 0x00, 0x00 },  /* ĩ to i */
  { 0x012A,  0x49, 0x00, 0x00, 0x00 },  /* Ī to I */
  { 0x012B,  0x69, 0x00, 0x00, 0x00 },  /* ī to i */
  { 0x012C,  0x49, 0x00, 0x00, 0x00 },  /* Ĭ to I */
  { 0x012D,  0x69, 0x00, 0x00, 0x00 },  /* ĭ to i */
  { 0x012E,  0x49, 0x00, 0x00, 0x00 },  /* Į to I */
  { 0x012F,  0x69, 0x00, 0x00, 0x00 },  /* į to i */
  { 0x0130,  0x49, 0x00, 0x00, 0x00 },  /* İ to I */
  { 0x0131,  0x69, 0x00, 0x00, 0x00 },  /* ı to i */
  { 0x0132,  0x49, 0x4A, 0x00, 0x00 },  /* Ĳ to IJ */
  { 0x0133,  0x69, 0x6A, 0x00, 0x00 },  /* ĳ to ij */
  { 0x0134,  0x4A, 0x68, 0x00, 0x00 },  /* Ĵ to Jh */
  { 0x0135,  0x6A, 0x68, 0x00, 0x00 },  /* ĵ to jh */
  { 0x0136,  0x4B, 0x00, 0x00, 0x00 },  /* Ķ to K */
  { 0x0137,  0x6B, 0x00, 0x00, 0x00 },  /* ķ to k */
  { 0x0138,  0x6B, 0x00, 0x00, 0x00 },  /* ĸ to k */
  { 0x0139,  0x4C, 0x00, 0x00, 0x00 },  /* Ĺ to L */
  { 0x013A,  0x6C, 0x00, 0x00, 0x00 },  /* ĺ to l */
  { 0x013B,  0x4C, 0x00, 0x00, 0x00 },  /* Ļ to L */
  { 0x013C,  0x6C, 0x00, 0x00, 0x00 },  /* ļ to l */
  { 0x013D,  0x4C, 0x00, 0x00, 0x00 },  /* Ľ to L */
  { 0x013E,  0x6C, 0x00, 0x00, 0x00 },  /* ľ to l */
  { 0x013F,  0x4C, 0x2E, 0x00, 0x00 },  /* Ŀ to L. */
  { 0x0140,  0x6C, 0x2E, 0x00, 0x00 },  /* ŀ to l. */
  { 0x0141,  0x4C, 0x00, 0x00, 0x00 },  /* Ł to L */
  { 0x0142,  0x6C, 0x00, 0x00, 0x00 },  /* ł to l */
  { 0x0143,  0x4E, 0x00, 0x00, 0x00 },  /* Ń to N */
  { 0x0144,  0x6E, 0x00, 0x00, 0x00 },  /* ń to n */
  { 0x0145,  0x4E, 0x00, 0x00, 0x00 },  /* Ņ to N */
  { 0x0146,  0x6E, 0x00, 0x00, 0x00 },  /* ņ to n */
  { 0x0147,  0x4E, 0x00, 0x00, 0x00 },  /* Ň to N */
  { 0x0148,  0x6E, 0x00, 0x00, 0x00 },  /* ň to n */
  { 0x0149,  0x27, 0x6E, 0x00, 0x00 },  /* ŉ to 'n */
  { 0x014A,  0x4E, 0x47, 0x00, 0x00 },  /* Ŋ to NG */
  { 0x014B,  0x6E, 0x67, 0x00, 0x00 },  /* ŋ to ng */
  { 0x014C,  0x4F, 0x00, 0x00, 0x00 },  /* Ō to O */
  { 0x014D,  0x6F, 0x00, 0x00, 0x00 },  /* ō to o */
  { 0x014E,  0x4F, 0x00, 0x00, 0x00 },  /* Ŏ to O */
  { 0x014F,  0x6F, 0x00, 0x00, 0x00 },  /* ŏ to o */
  { 0x0150,  0x4F, 0x00, 0x00, 0x00 },  /* Ő to O */
  { 0x0151,  0x6F, 0x00, 0x00, 0x00 },  /* ő to o */
  { 0x0152,  0x4F, 0x45, 0x00, 0x00 },  /* Œ to OE */
  { 0x0153,  0x6F, 0x65, 0x00, 0x00 },  /* œ to oe */
  { 0x0154,  0x52, 0x00, 0x00, 0x00 },  /* Ŕ to R */
  { 0x0155,  0x72, 0x00, 0x00, 0x00 },  /* ŕ to r */
  { 0x0156,  0x52, 0x00, 0x00, 0x00 },  /* Ŗ to R */
  { 0x0157,  0x72, 0x00, 0x00, 0x00 },  /* ŗ to r */
  { 0x0158,  0x52, 0x00, 0x00, 0x00 },  /* Ř to R */
  { 0x0159,  0x72, 0x00, 0x00, 0x00 },  /* ř to r */
  { 0x015A,  0x53, 0x00, 0x00, 0x00 },  /* Ś to S */
  { 0x015B,  0x73, 0x00, 0x00, 0x00 },  /* ś to s */
  { 0x015C,  0x53, 0x68, 0x00, 0x00 },  /* Ŝ to Sh */
  { 0x015D,  0x73, 0x68, 0x00, 0x00 },  /* ŝ to sh */
  { 0x015E,  0x53, 0x00, 0x00, 0x00 },  /* Ş to S */
  { 0x015F,  0x73, 0x00, 0x00, 0x00 },  /* ş to s */
  { 0x0160,  0x53, 0x00, 0x00, 0x00 },  /* Š to S */
  { 0x0161,  0x73, 0x00, 0x00, 0x00 },  /* š to s */
  { 0x0162,  0x54, 0x00, 0x00, 0x00 },  /* Ţ to T */
  { 0x0163,  0x74, 0x00, 0x00, 0x00 },  /* ţ to t */
  { 0x0164,  0x54, 0x00, 0x00, 0x00 },  /* Ť to T */
  { 0x0165,  0x74, 0x00, 0x00, 0x00 },  /* ť to t */
  { 0x0166,  0x54, 0x00, 0x00, 0x00 },  /* Ŧ to T */
  { 0x0167,  0x74, 0x00, 0x00, 0x00 },  /* ŧ to t */
  { 0x0168,  0x55, 0x00, 0x00, 0x00 },  /* Ũ to U */
  { 0x0169,  0x75, 0x00, 0x00, 0x00 },  /* ũ to u */
  { 0x016A,  0x55, 0x00, 0x00, 0x00 },  /* Ū to U */
  { 0x016B,  0x75, 0x00, 0x00, 0x00 },  /* ū to u */
  { 0x016C,  0x55, 0x00, 0x00, 0x00 },  /* Ŭ to U */
  { 0x016D,  0x75, 0x00, 0x00, 0x00 },  /* ŭ to u */
  { 0x016E,  0x55, 0x00, 0x00, 0x00 },  /* Ů to U */
  { 0x016F,  0x75, 0x00, 0x00, 0x00 },  /* ů to u */
  { 0x0170,  0x55, 0x00, 0x00, 0x00 },  /* Ű to U */
  { 0x0171,  0x75, 0x00, 0x00, 0x00 },  /* ű to u */
  { 0x0172,  0x55, 0x00, 0x00, 0x00 },  /* Ų to U */
  { 0x0173,  0x75, 0x00, 0x00, 0x00 },  /* ų to u */
  { 0x0174,  0x57, 0x00, 0x00, 0x00 },  /* Ŵ to W */
  { 0x0175,  0x77, 0x00, 0x00, 0x00 },  /* ŵ to w */
  { 0x0176,  0x59, 0x00, 0x00, 0x00 },  /* Ŷ to Y */
  { 0x0177,  0x79, 0x00, 0x00, 0x00 },  /* ŷ to y */
  { 0x0178,  0x59, 0x00, 0x00, 0x00 },  /* Ÿ to Y */
  { 0x0179,  0x5A, 0x00, 0x00, 0x00 },  /* Ź to Z */
  { 0x017A,  0x7A, 0x00, 0x00, 0x00 },  /* ź to z */
  { 0x017B,  0x5A, 0x00, 0x00, 0x00 },  /* Ż to Z */
  { 0x017C,  0x7A, 0x00, 0x00, 0x00 },  /* ż to z */
  { 0x017D,  0x5A, 0x00, 0x00, 0x00 },  /* Ž to Z */
  { 0x017E,  0x7A, 0x00, 0x00, 0x00 },  /* ž to z */
  { 0x017F,  0x73, 0x00, 0x00, 0x00 },  /* ſ to s */
  { 0x0192,  0x66, 0x00, 0x00, 0x00 },  /* ƒ to f */
  { 0x0218,  0x53, 0x00, 0x00, 0x00 },  /* Ș to S */
  { 0x0219,  0x73, 0x00, 0x00, 0x00 },  /* ș to s */
  { 0x021A,  0x54, 0x00, 0x00, 0x00 },  /* Ț to T */
  { 0x021B,  0x74, 0x00, 0x00, 0x00 },  /* ț to t */
  { 0x0386,  0x41, 0x00, 0x00, 0x00 },  /* Ά to A */
  { 0x0388,  0x45, 0x00, 0x00, 0x00 },  /* Έ to E */
  { 0x0389,  0x49, 0x00, 0x00, 0x00 },  /* Ή to I */
  { 0x038A,  0x49, 0x00, 0x00, 0x00 },  /* Ί to I */
  { 0x038C,  0x4f, 0x00, 0x00, 0x00 },  /* Ό to O */
  { 0x038E,  0x59, 0x00, 0x00, 0x00 },  /* Ύ to Y */
  { 0x038F,  0x4f, 0x00, 0x00, 0x00 },  /* Ώ to O */
  { 0x0390,  0x69, 0x00, 0x00, 0x00 },  /* ΐ to i */
  { 0x0391,  0x41, 0x00, 0x00, 0x00 },  /* Α to A */
  { 0x0392,  0x42, 0x00, 0x00, 0x00 },  /* Β to B */
  { 0x0393,  0x47, 0x00, 0x00, 0x00 },  /* Γ to G */
  { 0x0394,  0x44, 0x00, 0x00, 0x00 },  /* Δ to D */
  { 0x0395,  0x45, 0x00, 0x00, 0x00 },  /* Ε to E */
  { 0x0396,  0x5a, 0x00, 0x00, 0x00 },  /* Ζ to Z */
  { 0x0397,  0x49, 0x00, 0x00, 0x00 },  /* Η to I */
  { 0x0398,  0x54, 0x68, 0x00, 0x00 },  /* Θ to Th */
  { 0x0399,  0x49, 0x00, 0x00, 0x00 },  /* Ι to I */
  { 0x039A,  0x4b, 0x00, 0x00, 0x00 },  /* Κ to K */
  { 0x039B,  0x4c, 0x00, 0x00, 0x00 },  /* Λ to L */
  { 0x039C,  0x4d, 0x00, 0x00, 0x00 },  /* Μ to M */
  { 0x039D,  0x4e, 0x00, 0x00, 0x00 },  /* Ν to N */
  { 0x039E,  0x58, 0x00, 0x00, 0x00 },  /* Ξ to X */
  { 0x039F,  0x4f, 0x00, 0x00, 0x00 },  /* Ο to O */
  { 0x03A0,  0x50, 0x00, 0x00, 0x00 },  /* Π to P */
  { 0x03A1,  0x52, 0x00, 0x00, 0x00 },  /* Ρ to R */
  { 0x03A3,  0x53, 0x00, 0x00, 0x00 },  /* Σ to S */
  { 0x03A4,  0x54, 0x00, 0x00, 0x00 },  /* Τ to T */
  { 0x03A5,  0x59, 0x00, 0x00, 0x00 },  /* Υ to Y */
  { 0x03A6,  0x46, 0x00, 0x00, 0x00 },  /* Φ to F */
  { 0x03A7,  0x43, 0x68, 0x00, 0x00 },  /* Χ to Ch */
  { 0x03A8,  0x50, 0x73, 0x00, 0x00 },  /* Ψ to Ps */
  { 0x03A9,  0x4f, 0x00, 0x00, 0x00 },  /* Ω to O */
  { 0x03AA,  0x49, 0x00, 0x00, 0x00 },  /* Ϊ to I */
  { 0x03AB,  0x59, 0x00, 0x00, 0x00 },  /* Ϋ to Y */
  { 0x03AC,  0x61, 0x00, 0x00, 0x00 },  /* ά to a */
  { 0x03AD,  0x65, 0x00, 0x00, 0x00 },  /* έ to e */
  { 0x03AE,  0x69, 0x00, 0x00, 0x00 },  /* ή to i */
  { 0x03AF,  0x69, 0x00, 0x00, 0x00 },  /* ί to i */
  { 0x03B1,  0x61, 0x00, 0x00, 0x00 },  /* α to a */
  { 0x03B2,  0x62, 0x00, 0x00, 0x00 },  /* β to b */
  { 0x03B3,  0x67, 0x00, 0x00, 0x00 },  /* γ to g */
  { 0x03B4,  0x64, 0x00, 0x00, 0x00 },  /* δ to d */
  { 0x03B5,  0x65, 0x00, 0x00, 0x00 },  /* ε to e */
  { 0x03B6,  0x7a, 0x00, 0x00, 0x00 },  /* ζ to z */
  { 0x03B7,  0x69, 0x00, 0x00, 0x00 },  /* η to i */
  { 0x03B8,  0x74, 0x68, 0x00, 0x00 },  /* θ to th */
  { 0x03B9,  0x69, 0x00, 0x00, 0x00 },  /* ι to i */
  { 0x03BA,  0x6b, 0x00, 0x00, 0x00 },  /* κ to k */
  { 0x03BB,  0x6c, 0x00, 0x00, 0x00 },  /* λ to l */
  { 0x03BC,  0x6d, 0x00, 0x00, 0x00 },  /* μ to m */
  { 0x03BD,  0x6e, 0x00, 0x00, 0x00 },  /* ν to n */
  { 0x03BE,  0x78, 0x00, 0x00, 0x00 },  /* ξ to x */
  { 0x03BF,  0x6f, 0x00, 0x00, 0x00 },  /* ο to o */
  { 0x03C0,  0x70, 0x00, 0x00, 0x00 },  /* π to p */
  { 0x03C1,  0x72, 0x00, 0x00, 0x00 },  /* ρ to r */
  { 0x03C3,  0x73, 0x00, 0x00, 0x00 },  /* σ to s */
  { 0x03C4,  0x74, 0x00, 0x00, 0x00 },  /* τ to t */
  { 0x03C5,  0x79, 0x00, 0x00, 0x00 },  /* υ to y */
  { 0x03C6,  0x66, 0x00, 0x00, 0x00 },  /* φ to f */
  { 0x03C7,  0x63, 0x68, 0x00, 0x00 },  /* χ to ch */
  { 0x03C8,  0x70, 0x73, 0x00, 0x00 },  /* ψ to ps */
  { 0x03C9,  0x6f, 0x00, 0x00, 0x00 },  /* ω to o */
  { 0x03CA,  0x69, 0x00, 0x00, 0x00 },  /* ϊ to i */
  { 0x03CB,  0x79, 0x00, 0x00, 0x00 },  /* ϋ to y */
  { 0x03CC,  0x6f, 0x00, 0x00, 0x00 },  /* ό to o */
  { 0x03CD,  0x79, 0x00, 0x00, 0x00 },  /* ύ to y */
  { 0x03CE,  0x69, 0x00, 0x00, 0x00 },  /* ώ to i */
  { 0x0400,  0x45, 0x00, 0x00, 0x00 },  /* Ѐ to E */
  { 0x0401,  0x45, 0x00, 0x00, 0x00 },  /* Ё to E */
  { 0x0402,  0x44, 0x00, 0x00, 0x00 },  /* Ђ to D */
  { 0x0403,  0x47, 0x00, 0x00, 0x00 },  /* Ѓ to G */
  { 0x0404,  0x45, 0x00, 0x00, 0x00 },  /* Є to E */
  { 0x0405,  0x5a, 0x00, 0x00, 0x00 },  /* Ѕ to Z */
  { 0x0406,  0x49, 0x00, 0x00, 0x00 },  /* І to I */
  { 0x0407,  0x49, 0x00, 0x00, 0x00 },  /* Ї to I */
  { 0x0408,  0x4a, 0x00, 0x00, 0x00 },  /* Ј to J */
  { 0x0409,  0x49, 0x00, 0x00, 0x00 },  /* Љ to I */
  { 0x040A,  0x4e, 0x00, 0x00, 0x00 },  /* Њ to N */
  { 0x040B,  0x44, 0x00, 0x00, 0x00 },  /* Ћ to D */
  { 0x040C,  0x4b, 0x00, 0x00, 0x00 },  /* Ќ to K */
  { 0x040D,  0x49, 0x00, 0x00, 0x00 },  /* Ѝ to I */
  { 0x040E,  0x55, 0x00, 0x00, 0x00 },  /* Ў to U */
  { 0x040F,  0x44, 0x00, 0x00, 0x00 },  /* Џ to D */
  { 0x0410,  0x41, 0x00, 0x00, 0x00 },  /* А to A */
  { 0x0411,  0x42, 0x00, 0x00, 0x00 },  /* Б to B */
  { 0x0412,  0x56, 0x00, 0x00, 0x00 },  /* В to V */
  { 0x0413,  0x47, 0x00, 0x00, 0x00 },  /* Г to G */
  { 0x0414,  0x44, 0x00, 0x00, 0x00 },  /* Д to D */
  { 0x0415,  0x45, 0x00, 0x00, 0x00 },  /* Е to E */
  { 0x0416,  0x5a, 0x68, 0x00, 0x00 },  /* Ж to Zh */
  { 0x0417,  0x5a, 0x00, 0x00, 0x00 },  /* З to Z */
  { 0x0418,  0x49, 0x00, 0x00, 0x00 },  /* И to I */
  { 0x0419,  0x49, 0x00, 0x00, 0x00 },  /* Й to I */
  { 0x041A,  0x4b, 0x00, 0x00, 0x00 },  /* К to K */
  { 0x041B,  0x4c, 0x00, 0x00, 0x00 },  /* Л to L */
  { 0x041C,  0x4d, 0x00, 0x00, 0x00 },  /* М to M */
  { 0x041D,  0x4e, 0x00, 0x00, 0x00 },  /* Н to N */
  { 0x041E,  0x4f, 0x00, 0x00, 0x00 },  /* О to O */
  { 0x041F,  0x50, 0x00, 0x00, 0x00 },  /* П to P */
  { 0x0420,  0x52, 0x00, 0x00, 0x00 },  /* Р to R */
  { 0x0421,  0x53, 0x00, 0x00, 0x00 },  /* С to S */
  { 0x0422,  0x54, 0x00, 0x00, 0x00 },  /* Т to T */
  { 0x0423,  0x55, 0x00, 0x00, 0x00 },  /* У to U */
  { 0x0424,  0x46, 0x00, 0x00, 0x00 },  /* Ф to F */
  { 0x0425,  0x4b, 0x68, 0x00, 0x00 },  /* Х to Kh */
  { 0x0426,  0x54, 0x63, 0x00, 0x00 },  /* Ц to Tc */
  { 0x0427,  0x43, 0x68, 0x00, 0x00 },  /* Ч to Ch */
  { 0x0428,  0x53, 0x68, 0x00, 0x00 },  /* Ш to Sh */
  { 0x0429,  0x53, 0x68, 0x63, 0x68 },  /* Щ to Shch */
  { 0x042A,  0x61, 0x00, 0x00, 0x00 },  /*  to A */
  { 0x042B,  0x59, 0x00, 0x00, 0x00 },  /* Ы to Y */
  { 0x042C,  0x59, 0x00, 0x00, 0x00 },  /*  to Y */
  { 0x042D,  0x45, 0x00, 0x00, 0x00 },  /* Э to E */
  { 0x042E,  0x49, 0x75, 0x00, 0x00 },  /* Ю to Iu */
  { 0x042F,  0x49, 0x61, 0x00, 0x00 },  /* Я to Ia */
  { 0x0430,  0x61, 0x00, 0x00, 0x00 },  /* а to a */
  { 0x0431,  0x62, 0x00, 0x00, 0x00 },  /* б to b */
  { 0x0432,  0x76, 0x00, 0x00, 0x00 },  /* в to v */
  { 0x0433,  0x67, 0x00, 0x00, 0x00 },  /* г to g */
  { 0x0434,  0x64, 0x00, 0x00, 0x00 },  /* д to d */
  { 0x0435,  0x65, 0x00, 0x00, 0x00 },  /* е to e */
  { 0x0436,  0x7a, 0x68, 0x00, 0x00 },  /* ж to zh */
  { 0x0437,  0x7a, 0x00, 0x00, 0x00 },  /* з to z */
  { 0x0438,  0x69, 0x00, 0x00, 0x00 },  /* и to i */
  { 0x0439,  0x69, 0x00, 0x00, 0x00 },  /* й to i */
  { 0x043A,  0x6b, 0x00, 0x00, 0x00 },  /* к to k */
  { 0x043B,  0x6c, 0x00, 0x00, 0x00 },  /* л to l */
  { 0x043C,  0x6d, 0x00, 0x00, 0x00 },  /* м to m */
  { 0x043D,  0x6e, 0x00, 0x00, 0x00 },  /* н to n */
  { 0x043E,  0x6f, 0x00, 0x00, 0x00 },  /* о to o */
  { 0x043F,  0x70, 0x00, 0x00, 0x00 },  /* п to p */
  { 0x0440,  0x72, 0x00, 0x00, 0x00 },  /* р to r */
  { 0x0441,  0x73, 0x00, 0x00, 0x00 },  /* с to s */
  { 0x0442,  0x74, 0x00, 0x00, 0x00 },  /* т to t */
  { 0x0443,  0x75, 0x00, 0x00, 0x00 },  /* у to u */
  { 0x0444,  0x66, 0x00, 0x00, 0x00 },  /* ф to f */
  { 0x0445,  0x6b, 0x68, 0x00, 0x00 },  /* х to kh */
  { 0x0446,  0x74, 0x63, 0x00, 0x00 },  /* ц to tc */
  { 0x0447,  0x63, 0x68, 0x00, 0x00 },  /* ч to ch */
  { 0x0448,  0x73, 0x68, 0x00, 0x00 },  /* ш to sh */
  { 0x0449,  0x73, 0x68, 0x63, 0x68 },  /* щ to shch */
  { 0x044A,  0x61, 0x00, 0x00, 0x00 },  /*  to a */
  { 0x044B,  0x79, 0x00, 0x00, 0x00 },  /* ы to y */
  { 0x044C,  0x79, 0x00, 0x00, 0x00 },  /*  to y */
  { 0x044D,  0x65, 0x00, 0x00, 0x00 },  /* э to e */
  { 0x044E,  0x69, 0x75, 0x00, 0x00 },  /* ю to iu */
  { 0x044F,  0x69, 0x61, 0x00, 0x00 },  /* я to ia */
  { 0x0450,  0x65, 0x00, 0x00, 0x00 },  /* ѐ to e */
  { 0x0451,  0x65, 0x00, 0x00, 0x00 },  /* ё to e */
  { 0x0452,  0x64, 0x00, 0x00, 0x00 },  /* ђ to d */
  { 0x0453,  0x67, 0x00, 0x00, 0x00 },  /* ѓ to g */
  { 0x0454,  0x65, 0x00, 0x00, 0x00 },  /* є to e */
  { 0x0455,  0x7a, 0x00, 0x00, 0x00 },  /* ѕ to z */
  { 0x0456,  0x69, 0x00, 0x00, 0x00 },  /* і to i */
  { 0x0457,  0x69, 0x00, 0x00, 0x00 },  /* ї to i */
  { 0x0458,  0x6a, 0x00, 0x00, 0x00 },  /* ј to j */
  { 0x0459,  0x69, 0x00, 0x00, 0x00 },  /* љ to i */
  { 0x045A,  0x6e, 0x00, 0x00, 0x00 },  /* њ to n */
  { 0x045B,  0x64, 0x00, 0x00, 0x00 },  /* ћ to d */
  { 0x045C,  0x6b, 0x00, 0x00, 0x00 },  /* ќ to k */
  { 0x045D,  0x69, 0x00, 0x00, 0x00 },  /* ѝ to i */
  { 0x045E,  0x75, 0x00, 0x00, 0x00 },  /* ў to u */
  { 0x045F,  0x64, 0x00, 0x00, 0x00 },  /* џ to d */
  { 0x1E02,  0x42, 0x00, 0x00, 0x00 },  /* Ḃ to B */
  { 0x1E03,  0x62, 0x00, 0x00, 0x00 },  /* ḃ to b */
  { 0x1E0A,  0x44, 0x00, 0x00, 0x00 },  /* Ḋ to D */
  { 0x1E0B,  0x64, 0x00, 0x00, 0x00 },  /* ḋ to d */
  { 0x1E1E,  0x46, 0x00, 0x00, 0x00 },  /* Ḟ to F */
  { 0x1E1F,  0x66, 0x00, 0x00, 0x00 },  /* ḟ to f */
  { 0x1E40,  0x4D, 0x00, 0x00, 0x00 },  /* Ṁ to M */
  { 0x1E41,  0x6D, 0x00, 0x00, 0x00 },  /* ṁ to m */
  { 0x1E56,  0x50, 0x00, 0x00, 0x00 },  /* Ṗ to P */
  { 0x1E57,  0x70, 0x00, 0x00, 0x00 },  /* ṗ to p */
  { 0x1E60,  0x53, 0x00, 0x00, 0x00 },  /* Ṡ to S */
  { 0x1E61,  0x73, 0x00, 0x00, 0x00 },  /* ṡ to s */
  { 0x1E6A,  0x54, 0x00, 0x00, 0x00 },  /* Ṫ to T */
  { 0x1E6B,  0x74, 0x00, 0x00, 0x00 },  /* ṫ to t */
  { 0x1E80,  0x57, 0x00, 0x00, 0x00 },  /* Ẁ to W */
  { 0x1E81,  0x77, 0x00, 0x00, 0x00 },  /* ẁ to w */
  { 0x1E82,  0x57, 0x00, 0x00, 0x00 },  /* Ẃ to W */
  { 0x1E83,  0x77, 0x00, 0x00, 0x00 },  /* ẃ to w */
  { 0x1E84,  0x57, 0x00, 0x00, 0x00 },  /* Ẅ to W */
  { 0x1E85,  0x77, 0x00, 0x00, 0x00 },  /* ẅ to w */
  { 0x1EF2,  0x59, 0x00, 0x00, 0x00 },  /* Ỳ to Y */
  { 0x1EF3,  0x79, 0x00, 0x00, 0x00 },  /* ỳ to y */
  { 0xFB00,  0x66, 0x66, 0x00, 0x00 },  /* ﬀ to ff */
  { 0xFB01,  0x66, 0x69, 0x00, 0x00 },  /* ﬁ to fi */
  { 0xFB02,  0x66, 0x6C, 0x00, 0x00 },  /* ﬂ to fl */
  { 0xFB05,  0x73, 0x74, 0x00, 0x00 },  /* ﬅ to st */
  { 0xFB06,  0x73, 0x74, 0x00, 0x00 },  /* ﬆ to st */
};

static const Transliteration *spellfixFindTranslit(int c, int *pxTop){
  *pxTop = (sizeof(translit)/sizeof(translit[0])) - 1;
  return translit;
}

/*
** Convert the input string from UTF-8 into pure ASCII by converting
** all non-ASCII characters to some combination of characters in the
** ASCII subset.
**
** The returned string might contain more characters than the input.
**
** Space to hold the returned string comes from sqlite3_malloc() and
** should be freed by the caller.
*/
static unsigned char *transliterate(const unsigned char *zIn, int nIn){
#ifdef SQLITE_SPELLFIX_5BYTE_MAPPINGS
  unsigned char *zOut = sqlite3_malloc64( nIn*5 + 1 );
#else
  unsigned char *zOut = sqlite3_malloc64( nIn*4 + 1 );
#endif
  int c, sz, nOut;
  if( zOut==0 ) return 0;
  nOut = 0;
  while( nIn>0 ){
    c = utf8Read(zIn, nIn, &sz);
    zIn += sz;
    nIn -= sz;
    if( c<=127 ){
      zOut[nOut++] = (unsigned char)c;
    }else{
      int xTop, xBtm, x;
      const Transliteration *tbl = spellfixFindTranslit(c, &xTop);
      xBtm = 0;
      while( xTop>=xBtm ){
        x = (xTop + xBtm)/2;
        if( tbl[x].cFrom==c ){
          zOut[nOut++] = tbl[x].cTo0;
          if( tbl[x].cTo1 ){
            zOut[nOut++] = tbl[x].cTo1;
            if( tbl[x].cTo2 ){
              zOut[nOut++] = tbl[x].cTo2;
              if( tbl[x].cTo3 ){
                zOut[nOut++] = tbl[x].cTo3;
#ifdef SQLITE_SPELLFIX_5BYTE_MAPPINGS
                if( tbl[x].cTo4 ){
                  zOut[nOut++] = tbl[x].cTo4;
                }
#endif /* SQLITE_SPELLFIX_5BYTE_MAPPINGS */
              }
            }
          }
          c = 0;
          break;
        }else if( tbl[x].cFrom>c ){
          xTop = x-1;
        }else{
          xBtm = x+1;
        }
      }
      if( c ) zOut[nOut++] = '?';
    }
  }
  zOut[nOut] = 0;
  return zOut;
}

/*
** Return the number of characters in the shortest prefix of the input
** string that transliterates to an ASCII string nTrans bytes or longer.
** Or, if the transliteration of the input string is less than nTrans
** bytes in size, return the number of characters in the input string.
*/
static int translen_to_charlen(const char *zIn, int nIn, int nTrans){
  int i, c, sz, nOut;
  int nChar;

  i = nOut = 0;
  for(nChar=0; i<nIn && nOut<nTrans; nChar++){
    c = utf8Read((const unsigned char *)&zIn[i], nIn-i, &sz);
    i += sz;

    nOut++;
    if( c>=128 ){
      int xTop, xBtm, x;
      const Transliteration *tbl = spellfixFindTranslit(c, &xTop);
      xBtm = 0;
      while( xTop>=xBtm ){
        x = (xTop + xBtm)/2;
        if( tbl[x].cFrom==c ){
          if( tbl[x].cTo1 ){
            nOut++;
            if( tbl[x].cTo2 ){
              nOut++;
              if( tbl[x].cTo3 ){
                nOut++;
              }
            }
          }
          break;
        }else if( tbl[x].cFrom>c ){
          xTop = x-1;
        }else{
          xBtm = x+1;
        }
      }
    }
  }

  return nChar;
}


/*
**    spellfix1_translit(X)
**
** Convert a string that contains non-ASCII Roman characters into 
** pure ASCII.
*/
static void transliterateSqlFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const unsigned char *zIn = sqlite3_value_text(argv[0]);
  int nIn = sqlite3_value_bytes(argv[0]);
  unsigned char *zOut = transliterate(zIn, nIn);
  if( zOut==0 ){
    sqlite3_result_error_nomem(context);
  }else{
    sqlite3_result_text(context, (char*)zOut, -1, sqlite3_free);
  }
}

/*
**    spellfix1_scriptcode(X)
**
** Try to determine the dominant script used by the word X and return
** its ISO 15924 numeric code.
**
** The current implementation only understands the following scripts:
**
**    215  (Latin)
**    220  (Cyrillic)
**    200  (Greek)
**
** This routine will return 998 if the input X contains characters from
** two or more of the above scripts or 999 if X contains no characters
** from any of the above scripts.
*/
static void scriptCodeSqlFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const unsigned char *zIn = sqlite3_value_text(argv[0]);
  int nIn = sqlite3_value_bytes(argv[0]);
  int c, sz;
  int scriptMask = 0;
  int res;
  int seenDigit = 0;
# define SCRIPT_LATIN       0x0001
# define SCRIPT_CYRILLIC    0x0002
# define SCRIPT_GREEK       0x0004
# define SCRIPT_HEBREW      0x0008
# define SCRIPT_ARABIC      0x0010

  while( nIn>0 ){
    c = utf8Read(zIn, nIn, &sz);
    zIn += sz;
    nIn -= sz;
    if( c<0x02af ){
      if( c>=0x80 || midClass[c&0x7f]<CCLASS_DIGIT ){
        scriptMask |= SCRIPT_LATIN;
      }else if( c>='0' && c<='9' ){
        seenDigit = 1;
      }
    }else if( c>=0x0400 && c<=0x04ff ){
      scriptMask |= SCRIPT_CYRILLIC;
    }else if( c>=0x0386 && c<=0x03ce ){
      scriptMask |= SCRIPT_GREEK;
    }else if( c>=0x0590 && c<=0x05ff ){
      scriptMask |= SCRIPT_HEBREW;
    }else if( c>=0x0600 && c<=0x06ff ){
      scriptMask |= SCRIPT_ARABIC;
    }
  }
  if( scriptMask==0 && seenDigit ) scriptMask = SCRIPT_LATIN;
  switch( scriptMask ){
    case 0:                res = 999; break;
    case SCRIPT_LATIN:     res = 215; break;
    case SCRIPT_CYRILLIC:  res = 220; break;
    case SCRIPT_GREEK:     res = 200; break;
    case SCRIPT_HEBREW:    res = 125; break;
    case SCRIPT_ARABIC:    res = 160; break;
    default:               res = 998; break;
  }
  sqlite3_result_int(context, res);
}

/* End transliterate
******************************************************************************
******************************************************************************
** Begin spellfix1 virtual table.
*/

/* Maximum length of a phonehash used for querying the shadow table */
#define SPELLFIX_MX_HASH  32

/* Maximum number of hash strings to examine per query */
#define SPELLFIX_MX_RUN   1

typedef struct spellfix1_vtab spellfix1_vtab;
typedef struct spellfix1_cursor spellfix1_cursor;

/* Fuzzy-search virtual table object */
struct spellfix1_vtab {
  sqlite3_vtab base;         /* Base class - must be first */
  sqlite3 *db;               /* Database connection */
  char *zDbName;             /* Name of database holding this table */
  char *zTableName;          /* Name of the virtual table */
  char *zCostTable;          /* Table holding edit-distance cost numbers */
  EditDist3Config *pConfig3; /* Parsed edit distance costs */
};

/* Fuzzy-search cursor object */
struct spellfix1_cursor {
  sqlite3_vtab_cursor base;    /* Base class - must be first */
  spellfix1_vtab *pVTab;       /* The table to which this cursor belongs */
  char *zPattern;              /* rhs of MATCH clause */
  int idxNum;                  /* idxNum value passed to xFilter() */
  int nRow;                    /* Number of rows of content */
  int nAlloc;                  /* Number of allocated rows */
  int iRow;                    /* Current row of content */
  int iLang;                   /* Value of the langid= constraint */
  int iTop;                    /* Value of the top= constraint */
  int iScope;                  /* Value of the scope= constraint */
  int nSearch;                 /* Number of vocabulary items checked */
  sqlite3_stmt *pFullScan;     /* Shadow query for a full table scan */
  struct spellfix1_row {       /* For each row of content */
    sqlite3_int64 iRowid;         /* Rowid for this row */
    char *zWord;                  /* Text for this row */
    int iRank;                    /* Rank for this row */
    int iDistance;                /* Distance from pattern for this row */
    int iScore;                   /* Score for sorting */
    int iMatchlen;                /* Value of matchlen column (or -1) */
    char zHash[SPELLFIX_MX_HASH]; /* the phonehash used for this match */
  } *a; 
};

/*
** Construct one or more SQL statements from the format string given
** and then evaluate those statements. The success code is written
** into *pRc.
**
** If *pRc is initially non-zero then this routine is a no-op.
*/
static void spellfix1DbExec(
  int *pRc,              /* Success code */
  sqlite3 *db,           /* Database in which to run SQL */
  const char *zFormat,   /* Format string for SQL */
  ...                    /* Arguments to the format string */
){
  va_list ap;
  char *zSql;
  if( *pRc ) return;
  va_start(ap, zFormat);
  zSql = sqlite3_vmprintf(zFormat, ap);
  va_end(ap);
  if( zSql==0 ){
    *pRc = SQLITE_NOMEM;
  }else{
    *pRc = sqlite3_exec(db, zSql, 0, 0, 0);
    sqlite3_free(zSql);
  }
}

/*
** xDisconnect/xDestroy method for the fuzzy-search module.
*/
static int spellfix1Uninit(int isDestroy, sqlite3_vtab *pVTab){
  spellfix1_vtab *p = (spellfix1_vtab*)pVTab;
  int rc = SQLITE_OK;
  if( isDestroy ){
    sqlite3 *db = p->db;
    spellfix1DbExec(&rc, db, "DROP TABLE IF EXISTS \"%w\".\"%w_vocab\"",
                  p->zDbName, p->zTableName);
  }
  if( rc==SQLITE_OK ){
    sqlite3_free(p->zTableName);
    editDist3ConfigDelete(p->pConfig3);
    sqlite3_free(p->zCostTable);
    sqlite3_free(p);
  }
  return rc;
}
static int spellfix1Disconnect(sqlite3_vtab *pVTab){
  return spellfix1Uninit(0, pVTab);
}
static int spellfix1Destroy(sqlite3_vtab *pVTab){
  return spellfix1Uninit(1, pVTab);
}

/*
** Make a copy of a string.  Remove leading and trailing whitespace
** and dequote it.
*/
static char *spellfix1Dequote(const char *zIn){
  char *zOut;
  int i, j;
  char c;
  while( isspace((unsigned char)zIn[0]) ) zIn++;
  zOut = sqlite3_mprintf("%s", zIn);
  if( zOut==0 ) return 0;
  i = (int)strlen(zOut);
#if 0  /* The parser will never leave spaces at the end */
  while( i>0 && isspace(zOut[i-1]) ){ i--; }
#endif
  zOut[i] = 0;
  c = zOut[0];
  if( c=='\'' || c=='"' ){
    for(i=1, j=0; ALWAYS(zOut[i]); i++){
      zOut[j++] = zOut[i];
      if( zOut[i]==c ){
        if( zOut[i+1]==c ){
          i++;
        }else{
          zOut[j-1] = 0;
          break;
        }
      }
    }
  }
  return zOut;
}


/*
** xConnect/xCreate method for the spellfix1 module. Arguments are:
**
**   argv[0]   -> module name  ("spellfix1")
**   argv[1]   -> database name
**   argv[2]   -> table name
**   argv[3].. -> optional arguments (i.e. "edit_cost_table" parameter)
*/
static int spellfix1Init(
  int isCreate,
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVTab,
  char **pzErr
){
  spellfix1_vtab *pNew = 0;
  /* const char *zModule = argv[0]; // not used */
  const char *zDbName = argv[1];
  const char *zTableName = argv[2];
  int nDbName;
  int rc = SQLITE_OK;
  int i;

  nDbName = (int)strlen(zDbName);
  pNew = sqlite3_malloc64( sizeof(*pNew) + nDbName + 1);
  if( pNew==0 ){
    rc = SQLITE_NOMEM;
  }else{
    memset(pNew, 0, sizeof(*pNew));
    pNew->zDbName = (char*)&pNew[1];
    memcpy(pNew->zDbName, zDbName, nDbName+1);
    pNew->zTableName = sqlite3_mprintf("%s", zTableName);
    pNew->db = db;
    if( pNew->zTableName==0 ){
      rc = SQLITE_NOMEM;
    }else{
      sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
      rc = sqlite3_declare_vtab(db, 
           "CREATE TABLE x(word,rank,distance,langid, "
           "score, matchlen, phonehash HIDDEN, "
           "top HIDDEN, scope HIDDEN, srchcnt HIDDEN, "
           "soundslike HIDDEN, command HIDDEN)"
      );
#define SPELLFIX_COL_WORD            0
#define SPELLFIX_COL_RANK            1
#define SPELLFIX_COL_DISTANCE        2
#define SPELLFIX_COL_LANGID          3
#define SPELLFIX_COL_SCORE           4
#define SPELLFIX_COL_MATCHLEN        5
#define SPELLFIX_COL_PHONEHASH       6
#define SPELLFIX_COL_TOP             7
#define SPELLFIX_COL_SCOPE           8
#define SPELLFIX_COL_SRCHCNT         9
#define SPELLFIX_COL_SOUNDSLIKE     10
#define SPELLFIX_COL_COMMAND        11
    }
    if( rc==SQLITE_OK && isCreate ){
      spellfix1DbExec(&rc, db,
         "CREATE TABLE IF NOT EXISTS \"%w\".\"%w_vocab\"(\n"
         "  id INTEGER PRIMARY KEY,\n"
         "  rank INT,\n"
         "  langid INT,\n"
         "  word TEXT,\n"
         "  k1 TEXT,\n"
         "  k2 TEXT\n"
         ");\n",
         zDbName, zTableName
      );
      spellfix1DbExec(&rc, db,
         "CREATE INDEX IF NOT EXISTS \"%w\".\"%w_vocab_index_langid_k2\" "
            "ON \"%w_vocab\"(langid,k2);",
         zDbName, zTableName, zTableName
      );
    }
    for(i=3; rc==SQLITE_OK && i<argc; i++){
      if( strncmp(argv[i],"edit_cost_table=",16)==0 && pNew->zCostTable==0 ){
        pNew->zCostTable = spellfix1Dequote(&argv[i][16]);
        if( pNew->zCostTable==0 ) rc = SQLITE_NOMEM;
        continue;
      }
      *pzErr = sqlite3_mprintf("bad argument to spellfix1(): \"%s\"", argv[i]);
      rc = SQLITE_ERROR; 
    }
  }

  if( rc && pNew ){
    *ppVTab = 0;
    spellfix1Uninit(0, &pNew->base);
  }else{
    *ppVTab = (sqlite3_vtab *)pNew;
  }
  return rc;
}

/*
** The xConnect and xCreate methods
*/
static int spellfix1Connect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVTab,
  char **pzErr
){
  return spellfix1Init(0, db, pAux, argc, argv, ppVTab, pzErr);
}
static int spellfix1Create(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVTab,
  char **pzErr
){
  return spellfix1Init(1, db, pAux, argc, argv, ppVTab, pzErr);
}

/*
** Clear all of the content from a cursor.
*/
static void spellfix1ResetCursor(spellfix1_cursor *pCur){
  int i;
  for(i=0; i<pCur->nRow; i++){
    sqlite3_free(pCur->a[i].zWord);
  }
  pCur->nRow = 0;
  pCur->iRow = 0;
  pCur->nSearch = 0;
  if( pCur->pFullScan ){
    sqlite3_finalize(pCur->pFullScan);
    pCur->pFullScan = 0;
  }
}

/*
** Resize the cursor to hold up to N rows of content
*/
static void spellfix1ResizeCursor(spellfix1_cursor *pCur, int N){
  struct spellfix1_row *aNew;
  assert( N>=pCur->nRow );
  aNew = sqlite3_realloc64(pCur->a, sizeof(pCur->a[0])*N);
  if( aNew==0 && N>0 ){
    spellfix1ResetCursor(pCur);
    sqlite3_free(pCur->a);
    pCur->nAlloc = 0;
    pCur->a = 0;
  }else{
    pCur->nAlloc = N;
    pCur->a = aNew;
  }
}


/*
** Close a fuzzy-search cursor.
*/
static int spellfix1Close(sqlite3_vtab_cursor *cur){
  spellfix1_cursor *pCur = (spellfix1_cursor *)cur;
  spellfix1ResetCursor(pCur);
  spellfix1ResizeCursor(pCur, 0);
  sqlite3_free(pCur->zPattern);
  sqlite3_free(pCur);
  return SQLITE_OK;
}

#define SPELLFIX_IDXNUM_MATCH  0x01         /* word MATCH $str */
#define SPELLFIX_IDXNUM_LANGID 0x02         /* langid == $langid */
#define SPELLFIX_IDXNUM_TOP    0x04         /* top = $top */
#define SPELLFIX_IDXNUM_SCOPE  0x08         /* scope = $scope */
#define SPELLFIX_IDXNUM_DISTLT 0x10         /* distance < $distance */
#define SPELLFIX_IDXNUM_DISTLE 0x20         /* distance <= $distance */
#define SPELLFIX_IDXNUM_ROWID  0x40         /* rowid = $rowid */
#define SPELLFIX_IDXNUM_DIST   (0x10|0x20)  /* DISTLT and DISTLE */

/*
**
** The plan number is a bitmask of the SPELLFIX_IDXNUM_* values defined
** above.
**
** filter.argv[*] values contains $str, $langid, $top, $scope and $rowid
** if specified and in that order.
*/
static int spellfix1BestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
  int iPlan = 0;
  int iLangTerm = -1;
  int iTopTerm = -1;
  int iScopeTerm = -1;
  int iDistTerm = -1;
  int iRowidTerm = -1;
  int i;
  const struct sqlite3_index_constraint *pConstraint;
  pConstraint = pIdxInfo->aConstraint;
  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
    if( pConstraint->usable==0 ) continue;

    /* Terms of the form:  word MATCH $str */
    if( (iPlan & SPELLFIX_IDXNUM_MATCH)==0 
     && pConstraint->iColumn==SPELLFIX_COL_WORD
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_MATCH
    ){
      iPlan |= SPELLFIX_IDXNUM_MATCH;
      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
      pIdxInfo->aConstraintUsage[i].omit = 1;
    }

    /* Terms of the form:  langid = $langid  */
    if( (iPlan & SPELLFIX_IDXNUM_LANGID)==0
     && pConstraint->iColumn==SPELLFIX_COL_LANGID
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= SPELLFIX_IDXNUM_LANGID;
      iLangTerm = i;
    }

    /* Terms of the form:  top = $top */
    if( (iPlan & SPELLFIX_IDXNUM_TOP)==0
     && pConstraint->iColumn==SPELLFIX_COL_TOP
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= SPELLFIX_IDXNUM_TOP;
      iTopTerm = i;
    }

    /* Terms of the form:  scope = $scope */
    if( (iPlan & SPELLFIX_IDXNUM_SCOPE)==0
     && pConstraint->iColumn==SPELLFIX_COL_SCOPE
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= SPELLFIX_IDXNUM_SCOPE;
      iScopeTerm = i;
    }

    /* Terms of the form:  distance < $dist or distance <= $dist */
    if( (iPlan & SPELLFIX_IDXNUM_DIST)==0
     && pConstraint->iColumn==SPELLFIX_COL_DISTANCE
     && (pConstraint->op==SQLITE_INDEX_CONSTRAINT_LT
          || pConstraint->op==SQLITE_INDEX_CONSTRAINT_LE)
    ){
      if( pConstraint->op==SQLITE_INDEX_CONSTRAINT_LT ){
        iPlan |= SPELLFIX_IDXNUM_DISTLT;
      }else{
        iPlan |= SPELLFIX_IDXNUM_DISTLE;
      }
      iDistTerm = i;
    }

    /* Terms of the form:  distance < $dist or distance <= $dist */
    if( (iPlan & SPELLFIX_IDXNUM_ROWID)==0
     && pConstraint->iColumn<0
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= SPELLFIX_IDXNUM_ROWID;
      iRowidTerm = i;
    }
  }
  if( iPlan&SPELLFIX_IDXNUM_MATCH ){
    int idx = 2;
    pIdxInfo->idxNum = iPlan;
    if( pIdxInfo->nOrderBy==1
     && pIdxInfo->aOrderBy[0].iColumn==SPELLFIX_COL_SCORE
     && pIdxInfo->aOrderBy[0].desc==0
    ){
      pIdxInfo->orderByConsumed = 1;  /* Default order by iScore */
    }
    if( iPlan&SPELLFIX_IDXNUM_LANGID ){
      pIdxInfo->aConstraintUsage[iLangTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iLangTerm].omit = 1;
    }
    if( iPlan&SPELLFIX_IDXNUM_TOP ){
      pIdxInfo->aConstraintUsage[iTopTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iTopTerm].omit = 1;
    }
    if( iPlan&SPELLFIX_IDXNUM_SCOPE ){
      pIdxInfo->aConstraintUsage[iScopeTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iScopeTerm].omit = 1;
    }
    if( iPlan&SPELLFIX_IDXNUM_DIST ){
      pIdxInfo->aConstraintUsage[iDistTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iDistTerm].omit = 1;
    }
    pIdxInfo->estimatedCost = 1e5;
  }else if( (iPlan & SPELLFIX_IDXNUM_ROWID) ){
    pIdxInfo->idxNum = SPELLFIX_IDXNUM_ROWID;
    pIdxInfo->aConstraintUsage[iRowidTerm].argvIndex = 1;
    pIdxInfo->aConstraintUsage[iRowidTerm].omit = 1;
    pIdxInfo->estimatedCost = 5;
  }else{
    pIdxInfo->idxNum = 0;
    pIdxInfo->estimatedCost = 1e50;
  }
  return SQLITE_OK;
}

/*
** Open a new fuzzy-search cursor.
*/
static int spellfix1Open(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  spellfix1_vtab *p = (spellfix1_vtab*)pVTab;
  spellfix1_cursor *pCur;
  pCur = sqlite3_malloc64( sizeof(*pCur) );
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(*pCur));
  pCur->pVTab = p;
  *ppCursor = &pCur->base;
  return SQLITE_OK;
}

/*
** Adjust a distance measurement by the words rank in order to show
** preference to common words.
*/
static int spellfix1Score(int iDistance, int iRank){
  int iLog2;
  for(iLog2=0; iRank>0; iLog2++, iRank>>=1){}
  return iDistance + 32 - iLog2;
}

/*
** Compare two spellfix1_row objects for sorting purposes in qsort() such
** that they sort in order of increasing distance.
*/
static int SQLITE_CDECL spellfix1RowCompare(const void *A, const void *B){
  const struct spellfix1_row *a = (const struct spellfix1_row*)A;
  const struct spellfix1_row *b = (const struct spellfix1_row*)B;
  return a->iScore - b->iScore;
}

/*
** A structure used to pass information from spellfix1FilterForMatch()
** into spellfix1RunQuery().
*/
typedef struct MatchQuery {
  spellfix1_cursor *pCur;          /* The cursor being queried */
  sqlite3_stmt *pStmt;             /* shadow table query statment */
  char zHash[SPELLFIX_MX_HASH];    /* The current phonehash for zPattern */
  const char *zPattern;            /* Transliterated input string */
  int nPattern;                    /* Length of zPattern */
  EditDist3FromString *pMatchStr3; /* Original unicode string */
  EditDist3Config *pConfig3;       /* Edit-distance cost coefficients */
  const EditDist3Lang *pLang;      /* The selected language coefficients */
  int iLang;                       /* The language id */
  int iScope;                      /* Default scope */
  int iMaxDist;                    /* Maximum allowed edit distance, or -1 */
  int rc;                          /* Error code */
  int nRun;                  /* Number of prior runs for the same zPattern */
  char azPrior[SPELLFIX_MX_RUN][SPELLFIX_MX_HASH];  /* Prior hashes */
} MatchQuery;

/*
** Run a query looking for the best matches against zPattern using
** zHash as the character class seed hash.
*/
static void spellfix1RunQuery(MatchQuery *p, const char *zQuery, int nQuery){
  const char *zK1;
  const char *zWord;
  int iDist;
  int iRank;
  int iScore;
  int iWorst = 0;
  int idx;
  int idxWorst = -1;
  int i;
  int iScope = p->iScope;
  spellfix1_cursor *pCur = p->pCur;
  sqlite3_stmt *pStmt = p->pStmt;
  char zHash1[SPELLFIX_MX_HASH];
  char zHash2[SPELLFIX_MX_HASH];
  char *zClass;
  int nClass;
  int rc;

  if( pCur->a==0 || p->rc ) return;   /* Prior memory allocation failure */
  zClass = (char*)phoneticHash((unsigned char*)zQuery, nQuery);
  if( zClass==0 ){
    p->rc = SQLITE_NOMEM;
    return;
  }
  nClass = (int)strlen(zClass);
  if( nClass>SPELLFIX_MX_HASH-2 ){
    nClass = SPELLFIX_MX_HASH-2;
    zClass[nClass] = 0;
  }
  if( nClass<=iScope ){
    if( nClass>2 ){
      iScope = nClass-1;
    }else{
      iScope = nClass;
    }
  }
  memcpy(zHash1, zClass, iScope);
  sqlite3_free(zClass);
  zHash1[iScope] = 0;
  memcpy(zHash2, zHash1, iScope);
  zHash2[iScope] = 'Z';
  zHash2[iScope+1] = 0;
#if SPELLFIX_MX_RUN>1
  for(i=0; i<p->nRun; i++){
    if( strcmp(p->azPrior[i], zHash1)==0 ) return;
  }
#endif
  assert( p->nRun<SPELLFIX_MX_RUN );
  memcpy(p->azPrior[p->nRun++], zHash1, iScope+1);
  if( sqlite3_bind_text(pStmt, 1, zHash1, -1, SQLITE_STATIC)==SQLITE_NOMEM
   || sqlite3_bind_text(pStmt, 2, zHash2, -1, SQLITE_STATIC)==SQLITE_NOMEM
  ){
    p->rc = SQLITE_NOMEM;
    return;
  }
#if SPELLFIX_MX_RUN>1
  for(i=0; i<pCur->nRow; i++){
    if( pCur->a[i].iScore>iWorst ){
      iWorst = pCur->a[i].iScore;
      idxWorst = i;
    }
  }
#endif
  while( sqlite3_step(pStmt)==SQLITE_ROW ){
    int iMatchlen = -1;
    iRank = sqlite3_column_int(pStmt, 2);
    if( p->pMatchStr3 ){
      int nWord = sqlite3_column_bytes(pStmt, 1);
      zWord = (const char*)sqlite3_column_text(pStmt, 1);
      iDist = editDist3Core(p->pMatchStr3, zWord, nWord, p->pLang, &iMatchlen);
    }else{
      zK1 = (const char*)sqlite3_column_text(pStmt, 3);
      if( zK1==0 ) continue;
      iDist = editdist1(p->zPattern, zK1, 0);
    }
    if( iDist<0 ){
      p->rc = SQLITE_NOMEM;
      break;
    }
    pCur->nSearch++;
    
    /* If there is a "distance < $dist" or "distance <= $dist" constraint,
    ** check if this row meets it. If not, jump back up to the top of the
    ** loop to process the next row. Otherwise, if the row does match the
    ** distance constraint, check if the pCur->a[] array is already full.
    ** If it is and no explicit "top = ?" constraint was present in the
    ** query, grow the array to ensure there is room for the new entry. */
    assert( (p->iMaxDist>=0)==((pCur->idxNum & SPELLFIX_IDXNUM_DIST) ? 1 : 0) );
    if( p->iMaxDist>=0 ){
      if( iDist>p->iMaxDist ) continue;
      if( pCur->nRow>=pCur->nAlloc && (pCur->idxNum & SPELLFIX_IDXNUM_TOP)==0 ){
        spellfix1ResizeCursor(pCur, pCur->nAlloc*2 + 10);
        if( pCur->a==0 ) break;
      }
    }

    iScore = spellfix1Score(iDist,iRank);
    if( pCur->nRow<pCur->nAlloc ){
      idx = pCur->nRow;
    }else if( iScore<iWorst ){
      idx = idxWorst;
      sqlite3_free(pCur->a[idx].zWord);
    }else{
      continue;
    }

    pCur->a[idx].zWord = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 1));
    if( pCur->a[idx].zWord==0 ){
      p->rc = SQLITE_NOMEM;
      break;
    }
    pCur->a[idx].iRowid = sqlite3_column_int64(pStmt, 0);
    pCur->a[idx].iRank = iRank;
    pCur->a[idx].iDistance = iDist;
    pCur->a[idx].iScore = iScore;
    pCur->a[idx].iMatchlen = iMatchlen;
    memcpy(pCur->a[idx].zHash, zHash1, iScope+1);
    if( pCur->nRow<pCur->nAlloc ) pCur->nRow++;
    if( pCur->nRow==pCur->nAlloc ){
      iWorst = pCur->a[0].iScore;
      idxWorst = 0;
      for(i=1; i<pCur->nRow; i++){
        iScore = pCur->a[i].iScore;
        if( iWorst<iScore ){
          iWorst = iScore;
          idxWorst = i;
        }
      }
    }
  }
  rc = sqlite3_reset(pStmt);
  if( rc ) p->rc = rc;
}

/*
** This version of the xFilter method work if the MATCH term is present
** and we are doing a scan.
*/
static int spellfix1FilterForMatch(
  spellfix1_cursor *pCur,
  int argc,
  sqlite3_value **argv
){
  int idxNum = pCur->idxNum;
  const unsigned char *zMatchThis;   /* RHS of the MATCH operator */
  EditDist3FromString *pMatchStr3 = 0; /* zMatchThis as an editdist string */
  char *zPattern;                    /* Transliteration of zMatchThis */
  int nPattern;                      /* Length of zPattern */
  int iLimit = 20;                   /* Max number of rows of output */
  int iScope = 3;                    /* Use this many characters of zClass */
  int iLang = 0;                     /* Language code */
  char *zSql;                        /* SQL of shadow table query */
  sqlite3_stmt *pStmt = 0;           /* Shadow table query */
  int rc;                            /* Result code */
  int idx = 1;                       /* Next available filter parameter */
  spellfix1_vtab *p = pCur->pVTab;   /* The virtual table that owns pCur */
  MatchQuery x;                      /* For passing info to RunQuery() */

  /* Load the cost table if we have not already done so */
  if( p->zCostTable!=0 && p->pConfig3==0 ){
    p->pConfig3 = sqlite3_malloc64( sizeof(p->pConfig3[0]) );
    if( p->pConfig3==0 ) return SQLITE_NOMEM;
    memset(p->pConfig3, 0, sizeof(p->pConfig3[0]));
    rc = editDist3ConfigLoad(p->pConfig3, p->db, p->zCostTable);
    if( rc ) return rc;
  }
  memset(&x, 0, sizeof(x));
  x.iScope = 3;  /* Default scope if none specified by "WHERE scope=N" */
  x.iMaxDist = -1;   /* Maximum allowed edit distance */

  if( idxNum&2 ){
    iLang = sqlite3_value_int(argv[idx++]);
  }
  if( idxNum&4 ){
    iLimit = sqlite3_value_int(argv[idx++]);
    if( iLimit<1 ) iLimit = 1;
  }
  if( idxNum&8 ){
    x.iScope = sqlite3_value_int(argv[idx++]);
    if( x.iScope<1 ) x.iScope = 1;
    if( x.iScope>SPELLFIX_MX_HASH-2 ) x.iScope = SPELLFIX_MX_HASH-2;
  }
  if( idxNum&(16|32) ){
    x.iMaxDist = sqlite3_value_int(argv[idx++]);
    if( idxNum&16 ) x.iMaxDist--;
    if( x.iMaxDist<0 ) x.iMaxDist = 0;
  }
  spellfix1ResetCursor(pCur);
  spellfix1ResizeCursor(pCur, iLimit);
  zMatchThis = sqlite3_value_text(argv[0]);
  if( zMatchThis==0 ) return SQLITE_OK;
  if( p->pConfig3 ){
    x.pLang = editDist3FindLang(p->pConfig3, iLang);
    pMatchStr3 = editDist3FromStringNew(x.pLang, (const char*)zMatchThis, -1);
    if( pMatchStr3==0 ){
      x.rc = SQLITE_NOMEM;
      goto filter_exit;
    }
  }else{
    x.pLang = 0;
  }
  zPattern = (char*)transliterate(zMatchThis, sqlite3_value_bytes(argv[0]));
  sqlite3_free(pCur->zPattern);
  pCur->zPattern = zPattern;
  if( zPattern==0 ){
    x.rc = SQLITE_NOMEM;
    goto filter_exit;
  }
  nPattern = (int)strlen(zPattern);
  if( zPattern[nPattern-1]=='*' ) nPattern--;
  zSql = sqlite3_mprintf(
     "SELECT id, word, rank, coalesce(k1,word)"
     "  FROM \"%w\".\"%w_vocab\""
     " WHERE langid=%d AND k2>=?1 AND k2<?2",
     p->zDbName, p->zTableName, iLang
  );
  if( zSql==0 ){
    x.rc = SQLITE_NOMEM;
    pStmt = 0;
    goto filter_exit;
  }
  rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
  sqlite3_free(zSql);
  pCur->iLang = iLang;
  x.pCur = pCur;
  x.pStmt = pStmt;
  x.zPattern = zPattern;
  x.nPattern = nPattern;
  x.pMatchStr3 = pMatchStr3;
  x.iLang = iLang;
  x.rc = rc;
  x.pConfig3 = p->pConfig3;
  if( x.rc==SQLITE_OK ){
    spellfix1RunQuery(&x, zPattern, nPattern);
  }

  if( pCur->a ){
    qsort(pCur->a, pCur->nRow, sizeof(pCur->a[0]), spellfix1RowCompare);
    pCur->iTop = iLimit;
    pCur->iScope = iScope;
  }else{
    x.rc = SQLITE_NOMEM;
  }

filter_exit:
  sqlite3_finalize(pStmt);
  editDist3FromStringDelete(pMatchStr3);
  return x.rc;
}

/*
** This version of xFilter handles a full-table scan case
*/
static int spellfix1FilterForFullScan(
  spellfix1_cursor *pCur,
  int argc,
  sqlite3_value **argv
){
  int rc = SQLITE_OK;
  int idxNum = pCur->idxNum;
  char *zSql;
  spellfix1_vtab *pVTab = pCur->pVTab;
  spellfix1ResetCursor(pCur);
  assert( idxNum==0 || idxNum==64 );
  zSql = sqlite3_mprintf(
     "SELECT word, rank, NULL, langid, id FROM \"%w\".\"%w_vocab\"%s",
     pVTab->zDbName, pVTab->zTableName,
     ((idxNum & 64) ? " WHERE rowid=?" : "")
  );
  if( zSql==0 ) return SQLITE_NOMEM;
  rc = sqlite3_prepare_v2(pVTab->db, zSql, -1, &pCur->pFullScan, 0);
  sqlite3_free(zSql);
  if( rc==SQLITE_OK && (idxNum & 64) ){
    assert( argc==1 );
    rc = sqlite3_bind_value(pCur->pFullScan, 1, argv[0]);
  }
  pCur->nRow = pCur->iRow = 0;
  if( rc==SQLITE_OK ){
    rc = sqlite3_step(pCur->pFullScan);
    if( rc==SQLITE_ROW ){ pCur->iRow = -1; rc = SQLITE_OK; }
    if( rc==SQLITE_DONE ){ rc = SQLITE_OK; }
  }else{
    pCur->iRow = 0;
  }
  return rc;
}


/*
** Called to "rewind" a cursor back to the beginning so that
** it starts its output over again.  Always called at least once
** prior to any spellfix1Column, spellfix1Rowid, or spellfix1Eof call.
*/
static int spellfix1Filter(
  sqlite3_vtab_cursor *cur, 
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  spellfix1_cursor *pCur = (spellfix1_cursor *)cur;
  int rc;
  pCur->idxNum = idxNum;
  if( idxNum & 1 ){
    rc = spellfix1FilterForMatch(pCur, argc, argv);
  }else{
    rc = spellfix1FilterForFullScan(pCur, argc, argv);
  }
  return rc;
}


/*
** Advance a cursor to its next row of output
*/
static int spellfix1Next(sqlite3_vtab_cursor *cur){
  spellfix1_cursor *pCur = (spellfix1_cursor *)cur;
  int rc = SQLITE_OK;
  if( pCur->iRow < pCur->nRow ){
    if( pCur->pFullScan ){
      rc = sqlite3_step(pCur->pFullScan);
      if( rc!=SQLITE_ROW ) pCur->iRow = pCur->nRow;
      if( rc==SQLITE_ROW || rc==SQLITE_DONE ) rc = SQLITE_OK;
    }else{
      pCur->iRow++;
    }
  }
  return rc;
}

/*
** Return TRUE if we are at the end-of-file
*/
static int spellfix1Eof(sqlite3_vtab_cursor *cur){
  spellfix1_cursor *pCur = (spellfix1_cursor *)cur;
  return pCur->iRow>=pCur->nRow;
}

/*
** Return columns from the current row.
*/
static int spellfix1Column(
  sqlite3_vtab_cursor *cur,
  sqlite3_context *ctx,
  int i
){
  spellfix1_cursor *pCur = (spellfix1_cursor*)cur;
  if( pCur->pFullScan ){
    if( i<=SPELLFIX_COL_LANGID ){
      sqlite3_result_value(ctx, sqlite3_column_value(pCur->pFullScan, i));
    }else{
      sqlite3_result_null(ctx);
    }
    return SQLITE_OK;
  }
  switch( i ){
    case SPELLFIX_COL_WORD: {
      sqlite3_result_text(ctx, pCur->a[pCur->iRow].zWord, -1, SQLITE_STATIC);
      break;
    }
    case SPELLFIX_COL_RANK: {
      sqlite3_result_int(ctx, pCur->a[pCur->iRow].iRank);
      break;
    }
    case SPELLFIX_COL_DISTANCE: {
      sqlite3_result_int(ctx, pCur->a[pCur->iRow].iDistance);
      break;
    }
    case SPELLFIX_COL_LANGID: {
      sqlite3_result_int(ctx, pCur->iLang);
      break;
    }
    case SPELLFIX_COL_SCORE: {
      sqlite3_result_int(ctx, pCur->a[pCur->iRow].iScore);
      break;
    }
    case SPELLFIX_COL_MATCHLEN: {
      int iMatchlen = pCur->a[pCur->iRow].iMatchlen;
      if( iMatchlen<0 ){
        int nPattern = (int)strlen(pCur->zPattern);
        char *zWord = pCur->a[pCur->iRow].zWord;
        int nWord = (int)strlen(zWord);

        if( nPattern>0 && pCur->zPattern[nPattern-1]=='*' ){
          char *zTranslit;
          int res;
          zTranslit = (char *)transliterate((unsigned char *)zWord, nWord);
          if( !zTranslit ) return SQLITE_NOMEM;
          res = editdist1(pCur->zPattern, zTranslit, &iMatchlen);
          sqlite3_free(zTranslit);
          if( res<0 ) return SQLITE_NOMEM;
          iMatchlen = translen_to_charlen(zWord, nWord, iMatchlen);
        }else{
          iMatchlen = utf8Charlen(zWord, nWord);
        }
      }

      sqlite3_result_int(ctx, iMatchlen);
      break;
    }
    case SPELLFIX_COL_PHONEHASH: {
      sqlite3_result_text(ctx, pCur->a[pCur->iRow].zHash, -1, SQLITE_STATIC);
      break;
    }
    case SPELLFIX_COL_TOP: {
      sqlite3_result_int(ctx, pCur->iTop);
      break;
    }
    case SPELLFIX_COL_SCOPE: {
      sqlite3_result_int(ctx, pCur->iScope);
      break;
    }
    case SPELLFIX_COL_SRCHCNT: {
      sqlite3_result_int(ctx, pCur->nSearch);
      break;
    }
    default: {
      sqlite3_result_null(ctx);
      break;
    }
  }
  return SQLITE_OK;
}

/*
** The rowid.
*/
static int spellfix1Rowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  spellfix1_cursor *pCur = (spellfix1_cursor*)cur;
  if( pCur->pFullScan ){
    *pRowid = sqlite3_column_int64(pCur->pFullScan, 4);
  }else{
    *pRowid = pCur->a[pCur->iRow].iRowid;
  }
  return SQLITE_OK;
}

/*
** This function is called by the xUpdate() method. It returns a string
** containing the conflict mode that xUpdate() should use for the current
** operation. One of: "ROLLBACK", "IGNORE", "ABORT" or "REPLACE".
*/
static const char *spellfix1GetConflict(sqlite3 *db){
  static const char *azConflict[] = {
    /* Note: Instead of "FAIL" - "ABORT". */
    "ROLLBACK", "IGNORE", "ABORT", "ABORT", "REPLACE"
  };
  int eConflict = sqlite3_vtab_on_conflict(db);

  assert( eConflict==SQLITE_ROLLBACK || eConflict==SQLITE_IGNORE
       || eConflict==SQLITE_FAIL || eConflict==SQLITE_ABORT
       || eConflict==SQLITE_REPLACE
  );
  assert( SQLITE_ROLLBACK==1 );
  assert( SQLITE_IGNORE==2 );
  assert( SQLITE_FAIL==3 );
  assert( SQLITE_ABORT==4 );
  assert( SQLITE_REPLACE==5 );

  return azConflict[eConflict-1];
}

/*
** The xUpdate() method.
*/
static int spellfix1Update(
  sqlite3_vtab *pVTab,
  int argc,
  sqlite3_value **argv,
  sqlite_int64 *pRowid
){
  int rc = SQLITE_OK;
  sqlite3_int64 rowid, newRowid;
  spellfix1_vtab *p = (spellfix1_vtab*)pVTab;
  sqlite3 *db = p->db;

  if( argc==1 ){
    /* A delete operation on the rowid given by argv[0] */
    rowid = *pRowid = sqlite3_value_int64(argv[0]);
    spellfix1DbExec(&rc, db, "DELETE FROM \"%w\".\"%w_vocab\" "
                           " WHERE id=%lld",
                  p->zDbName, p->zTableName, rowid);
  }else{
    const unsigned char *zWord = sqlite3_value_text(argv[SPELLFIX_COL_WORD+2]);
    int nWord = sqlite3_value_bytes(argv[SPELLFIX_COL_WORD+2]);
    int iLang = sqlite3_value_int(argv[SPELLFIX_COL_LANGID+2]);
    int iRank = sqlite3_value_int(argv[SPELLFIX_COL_RANK+2]);
    const unsigned char *zSoundslike =
           sqlite3_value_text(argv[SPELLFIX_COL_SOUNDSLIKE+2]);
    int nSoundslike = sqlite3_value_bytes(argv[SPELLFIX_COL_SOUNDSLIKE+2]);
    char *zK1, *zK2;
    int i;
    char c;
    const char *zConflict = spellfix1GetConflict(db);

    if( zWord==0 ){
      /* Inserts of the form:  INSERT INTO table(command) VALUES('xyzzy');
      ** cause zWord to be NULL, so we look at the "command" column to see
      ** what special actions to take */
      const char *zCmd = 
         (const char*)sqlite3_value_text(argv[SPELLFIX_COL_COMMAND+2]);
      if( zCmd==0 ){
        pVTab->zErrMsg = sqlite3_mprintf("NOT NULL constraint failed: %s.word",
                                         p->zTableName);
        return SQLITE_CONSTRAINT_NOTNULL;
      }
      if( strcmp(zCmd,"reset")==0 ){
        /* Reset the  edit cost table (if there is one). */
        editDist3ConfigDelete(p->pConfig3);
        p->pConfig3 = 0;
        return SQLITE_OK;
      }
      if( strncmp(zCmd,"edit_cost_table=",16)==0 ){
        editDist3ConfigDelete(p->pConfig3);
        p->pConfig3 = 0;
        sqlite3_free(p->zCostTable);
        p->zCostTable = spellfix1Dequote(zCmd+16);
        if( p->zCostTable==0 ) return SQLITE_NOMEM;
        if( p->zCostTable[0]==0 || sqlite3_stricmp(p->zCostTable,"null")==0 ){
          sqlite3_free(p->zCostTable);
          p->zCostTable = 0;
        }
        return SQLITE_OK;
      }
      pVTab->zErrMsg = sqlite3_mprintf("unknown value for %s.command: \"%w\"",
                                       p->zTableName, zCmd);
      return SQLITE_ERROR;
    }
    if( iRank<1 ) iRank = 1;
    if( zSoundslike ){
      zK1 = (char*)transliterate(zSoundslike, nSoundslike);
    }else{
      zK1 = (char*)transliterate(zWord, nWord);
    }
    if( zK1==0 ) return SQLITE_NOMEM;
    for(i=0; (c = zK1[i])!=0; i++){
       if( c>='A' && c<='Z' ) zK1[i] += 'a' - 'A';
    }
    zK2 = (char*)phoneticHash((const unsigned char*)zK1, i);
    if( zK2==0 ){
      sqlite3_free(zK1);
      return SQLITE_NOMEM;
    }
    if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
      if( sqlite3_value_type(argv[1])==SQLITE_NULL ){
        spellfix1DbExec(&rc, db,
               "INSERT INTO \"%w\".\"%w_vocab\"(rank,langid,word,k1,k2) "
               "VALUES(%d,%d,%Q,nullif(%Q,%Q),%Q)",
               p->zDbName, p->zTableName,
               iRank, iLang, zWord, zK1, zWord, zK2
        );
      }else{
        newRowid = sqlite3_value_int64(argv[1]);
        spellfix1DbExec(&rc, db,
            "INSERT OR %s INTO \"%w\".\"%w_vocab\"(id,rank,langid,word,k1,k2) "
            "VALUES(%lld,%d,%d,%Q,nullif(%Q,%Q),%Q)",
            zConflict, p->zDbName, p->zTableName,
            newRowid, iRank, iLang, zWord, zK1, zWord, zK2
        );
      }
      *pRowid = sqlite3_last_insert_rowid(db);
    }else{
      rowid = sqlite3_value_int64(argv[0]);
      newRowid = *pRowid = sqlite3_value_int64(argv[1]);
      spellfix1DbExec(&rc, db,
             "UPDATE OR %s \"%w\".\"%w_vocab\" SET id=%lld, rank=%d, langid=%d,"
             " word=%Q, k1=nullif(%Q,%Q), k2=%Q WHERE id=%lld",
             zConflict, p->zDbName, p->zTableName, newRowid, iRank, iLang,
             zWord, zK1, zWord, zK2, rowid
      );
    }
    sqlite3_free(zK1);
    sqlite3_free(zK2);
  }
  return rc;
}

/*
** Rename the spellfix1 table.
*/
static int spellfix1Rename(sqlite3_vtab *pVTab, const char *zNew){
  spellfix1_vtab *p = (spellfix1_vtab*)pVTab;
  sqlite3 *db = p->db;
  int rc = SQLITE_OK;
  char *zNewName = sqlite3_mprintf("%s", zNew);
  if( zNewName==0 ){
    return SQLITE_NOMEM;
  }
  spellfix1DbExec(&rc, db, 
     "ALTER TABLE \"%w\".\"%w_vocab\" RENAME TO \"%w_vocab\"",
     p->zDbName, p->zTableName, zNewName
  );
  if( rc==SQLITE_OK ){
    sqlite3_free(p->zTableName);
    p->zTableName = zNewName;
  }else{
    sqlite3_free(zNewName);
  }
  return rc;
}


/*
** A virtual table module that provides fuzzy search.
*/
static sqlite3_module spellfix1Module = {
  0,                       /* iVersion */
  spellfix1Create,         /* xCreate - handle CREATE VIRTUAL TABLE */
  spellfix1Connect,        /* xConnect - reconnected to an existing table */
  spellfix1BestIndex,      /* xBestIndex - figure out how to do a query */
  spellfix1Disconnect,     /* xDisconnect - close a connection */
  spellfix1Destroy,        /* xDestroy - handle DROP TABLE */
  spellfix1Open,           /* xOpen - open a cursor */
  spellfix1Close,          /* xClose - close a cursor */
  spellfix1Filter,         /* xFilter - configure scan constraints */
  spellfix1Next,           /* xNext - advance a cursor */
  spellfix1Eof,            /* xEof - check for end of scan */
  spellfix1Column,         /* xColumn - read data */
  spellfix1Rowid,          /* xRowid - read data */
  spellfix1Update,         /* xUpdate */
  0,                       /* xBegin */
  0,                       /* xSync */
  0,                       /* xCommit */
  0,                       /* xRollback */
  0,                       /* xFindMethod */
  spellfix1Rename,         /* xRename */
  0,                       /* xSavepoint */
  0,                       /* xRelease */
  0,                       /* xRollbackTo */
  0,                       /* xShadowName */
  0                        /* xIntegrity */
};

/*
** Register the various functions and the virtual table.
*/
static int spellfix1Register(sqlite3 *db){
  int rc = SQLITE_OK;
  unsigned int i;
  rc = sqlite3_create_function(db, "spellfix1_translit", 1,
                               SQLITE_UTF8|SQLITE_DETERMINISTIC, 0,
                                transliterateSqlFunc, 0, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(db, "spellfix1_editdist", 2,
                                 SQLITE_UTF8|SQLITE_DETERMINISTIC, 0,
                                  editdistSqlFunc, 0, 0);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(db, "spellfix1_phonehash", 1,
                                 SQLITE_UTF8|SQLITE_DETERMINISTIC, 0,
                                  phoneticHashSqlFunc, 0, 0);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(db, "spellfix1_scriptcode", 1,
                                  SQLITE_UTF8|SQLITE_DETERMINISTIC, 0,
                                  scriptCodeSqlFunc, 0, 0);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_module(db, "spellfix1", &spellfix1Module, 0);
  }
  if( rc==SQLITE_OK ){
    rc = editDist3Install(db);
  }

  /* Verify sanity of the translit[] table */
  for(i=0; i<sizeof(translit)/sizeof(translit[0])-1; i++){
    assert( translit[i].cFrom<translit[i+1].cFrom );
  }

  return rc;
}

#endif /* SQLITE_OMIT_VIRTUALTABLE */

/*
** Extension load function.
*/
#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_spellfix_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  SQLITE_EXTENSION_INIT2(pApi);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  return spellfix1Register(db);
#endif
  return SQLITE_OK;
}