SQLite

    *paOut = pOut;
    *pnOut = nOut;
  }else{
    sqlite3_free(pOut);
  }
  return rc;
}





































































/*
** Evaluate the full-text expression pExpr against fts3 table pTab. Store
** the resulting doclist in *paOut and *pnOut.
*/
static int evalFts3Expr(
  Fts3Table *p,                   /* Virtual table handle */

            || pExpr->eType==FTSQUERY_AND  || pExpr->eType==FTSQUERY_NOT
        );
        switch( pExpr->eType ){
          case FTSQUERY_NEAR: {
            Fts3Expr *pLeft;
            Fts3Expr *pRight;
            int mergetype = isReqPos ? MERGE_POS_NEAR : MERGE_NEAR;
            int nParam1;
            int nParam2;
            char *aBuffer;
           
            if( pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR ){
              mergetype = MERGE_POS_NEAR;
            }
            pLeft = pExpr->pLeft;
            while( pLeft->eType==FTSQUERY_NEAR ){ 
              pLeft=pLeft->pRight;
            }
            pRight = pExpr->pRight;
            assert( pRight->eType==FTSQUERY_PHRASE );
            assert( pLeft->eType==FTSQUERY_PHRASE );

            nParam1 = pExpr->nNear+1;
            nParam2 = nParam1+pLeft->pPhrase->nToken+pRight->pPhrase->nToken-2;
            aBuffer = sqlite3_malloc(nLeft+nRight+1);
            rc = fts3DoclistMerge(mergetype, nParam1, nParam2, aBuffer,
                pnOut, aLeft, nLeft, aRight, nRight

            );
            if( rc!=SQLITE_OK ){
              sqlite3_free(aBuffer);
            }else{
              *paOut = aBuffer;
            }
            sqlite3_free(aLeft);
            break;
          }

          case FTSQUERY_OR: {
            /* Allocate a buffer for the output. The maximum size is the
            ** sum of the sizes of the two input buffers. The +1 term is

          }
          while( iThis<iCol ){
            fts3ColumnlistCopy(0, &pCsr);
            if( *pCsr==0x00 ) return 0;
            pCsr++;
            pCsr += sqlite3Fts3GetVarint32(pCsr, &iThis);
          }
          if( iCol==iThis ) return pCsr;
        }
        return 0;
      }
    }
  }

  return 0;

  int nVal,                       /* Size of apVal[] array */
  sqlite3_value **apVal           /* Array of arguments */
){
  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
  const char *zStart = "<b>";
  const char *zEnd = "</b>";
  const char *zEllipsis = "<b>...</b>";

  /* There must be at least one argument passed to this function (otherwise
  ** the non-overloaded version would have been called instead of this one).
  */
  assert( nVal>=1 );

  if( nVal>4 ){
    sqlite3_result_error(pContext, 
        "wrong number of arguments to function snippet()", -1);
    return;
  }
  if( fts3FunctionArg(pContext, "snippet", apVal[0], &pCsr) ) return;

  switch( nVal ){
    case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
    case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
    case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
  }
  if( !zEllipsis || !zEnd || !zStart ){
    sqlite3_result_error_nomem(pContext);
  }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
    sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis);
  }
}

/*
** Implementation of the snippet2() function for FTS3
*/
static void fts3Snippet2Func(
  sqlite3_context *pContext,      /* SQLite function call context */
  int nVal,                       /* Size of apVal[] array */
  sqlite3_value **apVal           /* Array of arguments */
){
  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
  const char *zStart = "<b>";
  const char *zEnd = "</b>";
  const char *zEllipsis = "<b>...</b>";
  int iCol = -1;
  int nToken = 10;

  /* There must be at least one argument passed to this function (otherwise
  ** the non-overloaded version would have been called instead of this one).
  */
  assert( nVal>=1 );

  if( nVal>6 ){

    case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
    case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
    case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
  }
  if( !zEllipsis || !zEnd || !zStart ){
    sqlite3_result_error_nomem(pContext);
  }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
    sqlite3Fts3Snippet2(pContext, pCsr, zStart, zEnd, zEllipsis, iCol, nToken);
  }
}

/*
** Implementation of the offsets() function for FTS3
*/
static void fts3OffsetsFunc(

  void **ppArg                    /* Unused */
){
  struct Overloaded {
    const char *zName;
    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
  } aOverload[] = {
    { "snippet", fts3SnippetFunc },
    { "snippet2", fts3Snippet2Func },
    { "offsets", fts3OffsetsFunc },
    { "optimize", fts3OptimizeFunc },
    { "matchinfo", fts3MatchinfoFunc },
  };
  int i;                          /* Iterator variable */

  UNUSED_PARAMETER(pVtab);

  /* Create the virtual table wrapper around the hash-table and overload 
  ** the two scalar functions. If this is successful, register the
  ** module with sqlite.
  */
  if( SQLITE_OK==rc 
   && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet2", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
  ){
    return sqlite3_create_module_v2(
        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
    );

int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
int sqlite3Fts3GetVarint32(const char *, int *);
int sqlite3Fts3VarintLen(sqlite3_uint64);
void sqlite3Fts3Dequote(char *);

char *sqlite3Fts3FindPositions(Fts3Expr *, sqlite3_int64, int);
int sqlite3Fts3ExprLoadDoclist(Fts3Table *, Fts3Expr *);


/* fts3_tokenizer.c */
const char *sqlite3Fts3NextToken(const char *, int *);
int sqlite3Fts3InitHashTable(sqlite3 *, Fts3Hash *, const char *);
int sqlite3Fts3InitTokenizer(Fts3Hash *pHash, 
  const char *, sqlite3_tokenizer **, const char **, char **
);

/* fts3_snippet.c */
void sqlite3Fts3Offsets(sqlite3_context*, Fts3Cursor*);
void sqlite3Fts3Snippet(sqlite3_context*, Fts3Cursor*, 
  const char *, const char *, const char *
);
void sqlite3Fts3Snippet2(sqlite3_context *, Fts3Cursor *, const char *,
  const char *, const char *, int, int
);
void sqlite3Fts3Matchinfo(sqlite3_context *, Fts3Cursor *);

/* fts3_expr.c */
int sqlite3Fts3ExprParse(sqlite3_tokenizer *, 
  char **, int, int, const char *, int, Fts3Expr **

#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

#include "fts3Int.h"
#include <string.h>
#include <assert.h>
#include <ctype.h>

typedef struct Snippet Snippet;

/*
** An instance of the following structure keeps track of generated
** matching-word offset information and snippets.
*/
struct Snippet {
  int nMatch;                     /* Total number of matches */
  int nAlloc;                     /* Space allocated for aMatch[] */
  struct snippetMatch {  /* One entry for each matching term */
    char snStatus;       /* Status flag for use while constructing snippets */
    short int nByte;     /* Number of bytes in the term */
    short int iCol;      /* The column that contains the match */
    short int iTerm;     /* The index in Query.pTerms[] of the matching term */
    int iToken;          /* The index of the matching document token */
    int iStart;          /* The offset to the first character of the term */
  } *aMatch;                      /* Points to space obtained from malloc */
  char *zOffset;                  /* Text rendering of aMatch[] */
  int nOffset;                    /* strlen(zOffset) */
  char *zSnippet;                 /* Snippet text */
  int nSnippet;                   /* strlen(zSnippet) */
};


/* It is not safe to call isspace(), tolower(), or isalnum() on
** hi-bit-set characters.  This is the same solution used in the
** tokenizer.
*/
static int fts3snippetIsspace(char c){
  return (c&0x80)==0 ? isspace(c) : 0;
}


/*
** A StringBuffer object holds a zero-terminated string that grows
** arbitrarily by appending.  Space to hold the string is obtained
** from sqlite3_malloc().  After any memory allocation failure, 
** StringBuffer.z is set to NULL and no further allocation is attempted.
*/
typedef struct StringBuffer {
  char *z;         /* Text of the string.  Space from malloc. */
  int nUsed;       /* Number bytes of z[] used, not counting \000 terminator */
  int nAlloc;      /* Bytes allocated for z[] */
} StringBuffer;


/*
** Initialize a new StringBuffer.
*/
static void fts3SnippetSbInit(StringBuffer *p){
  p->nAlloc = 100;
  p->nUsed = 0;
  p->z = sqlite3_malloc( p->nAlloc );
}

/*
** Append text to the string buffer.
*/
static void fts3SnippetAppend(StringBuffer *p, const char *zNew, int nNew){
  if( p->z==0 ) return;
  if( nNew<0 ) nNew = (int)strlen(zNew);
  if( p->nUsed + nNew >= p->nAlloc ){
    int nAlloc;
    char *zNew;

    nAlloc = p->nUsed + nNew + p->nAlloc;
    zNew = sqlite3_realloc(p->z, nAlloc);
    if( zNew==0 ){
      sqlite3_free(p->z);
      p->z = 0;
      return;
    }
    p->z = zNew;
    p->nAlloc = nAlloc;
  }
  memcpy(&p->z[p->nUsed], zNew, nNew);
  p->nUsed += nNew;
  p->z[p->nUsed] = 0;
}

/* If the StringBuffer ends in something other than white space, add a
** single space character to the end.
*/
static void fts3SnippetAppendWhiteSpace(StringBuffer *p){
  if( p->z && p->nUsed && !fts3snippetIsspace(p->z[p->nUsed-1]) ){
    fts3SnippetAppend(p, " ", 1);
  }
}

/* Remove white space from the end of the StringBuffer */
static void fts3SnippetTrimWhiteSpace(StringBuffer *p){
  if( p->z ){
    while( p->nUsed && fts3snippetIsspace(p->z[p->nUsed-1]) ){
      p->nUsed--;
    }
    p->z[p->nUsed] = 0;
  }
}

/* 
** Release all memory associated with the Snippet structure passed as
** an argument.
*/
static void fts3SnippetFree(Snippet *p){
  if( p ){
    sqlite3_free(p->aMatch);
    sqlite3_free(p->zOffset);
    sqlite3_free(p->zSnippet);
    sqlite3_free(p);
  }
}

/*
** Append a single entry to the p->aMatch[] log.
*/
static int snippetAppendMatch(
  Snippet *p,               /* Append the entry to this snippet */
  int iCol, int iTerm,      /* The column and query term */
  int iToken,               /* Matching token in document */
  int iStart, int nByte     /* Offset and size of the match */
){
  int i;
  struct snippetMatch *pMatch;
  if( p->nMatch+1>=p->nAlloc ){
    struct snippetMatch *pNew;
    p->nAlloc = p->nAlloc*2 + 10;
    pNew = sqlite3_realloc(p->aMatch, p->nAlloc*sizeof(p->aMatch[0]) );
    if( pNew==0 ){
      p->aMatch = 0;
      p->nMatch = 0;
      p->nAlloc = 0;
      return SQLITE_NOMEM;
    }
    p->aMatch = pNew;
  }
  i = p->nMatch++;
  pMatch = &p->aMatch[i];
  pMatch->iCol = (short)iCol;
  pMatch->iTerm = (short)iTerm;
  pMatch->iToken = iToken;
  pMatch->iStart = iStart;
  pMatch->nByte = (short)nByte;
  return SQLITE_OK;
}

/*
** Sizing information for the circular buffer used in snippetOffsetsOfColumn()
*/
#define FTS3_ROTOR_SZ   (32)
#define FTS3_ROTOR_MASK (FTS3_ROTOR_SZ-1)

/*
** Function to iterate through the tokens of a compiled expression.
**
** Except, skip all tokens on the right-hand side of a NOT operator.
** This function is used to find tokens as part of snippet and offset
** generation and we do nt want snippets and offsets to report matches
** for tokens on the RHS of a NOT.
*/
static int fts3NextExprToken(Fts3Expr **ppExpr, int *piToken){
  Fts3Expr *p = *ppExpr;
  int iToken = *piToken;
  if( iToken<0 ){
    /* In this case the expression p is the root of an expression tree.
    ** Move to the first token in the expression tree.
    */
    while( p->pLeft ){
      p = p->pLeft;
    }
    iToken = 0;
  }else{
    assert(p && p->eType==FTSQUERY_PHRASE );
    if( iToken<(p->pPhrase->nToken-1) ){
      iToken++;
    }else{
      iToken = 0;
      while( p->pParent && p->pParent->pLeft!=p ){
        assert( p->pParent->pRight==p );
        p = p->pParent;
      }
      p = p->pParent;
      if( p ){
        assert( p->pRight!=0 );
        p = p->pRight;
        while( p->pLeft ){
          p = p->pLeft;
        }
      }
    }
  }

  *ppExpr = p;
  *piToken = iToken;
  return p?1:0;
}

/*
** Return TRUE if the expression node pExpr is located beneath the
** RHS of a NOT operator.
*/
static int fts3ExprBeneathNot(Fts3Expr *p){
  Fts3Expr *pParent;
  while( p ){
    pParent = p->pParent;
    if( pParent && pParent->eType==FTSQUERY_NOT && pParent->pRight==p ){
      return 1;
    }
    p = pParent;
  }
  return 0;
}

/*
** Add entries to pSnippet->aMatch[] for every match that occurs against
** document zDoc[0..nDoc-1] which is stored in column iColumn.
*/
static int snippetOffsetsOfColumn(
  Fts3Cursor *pCur,         /* The fulltest search cursor */
  Snippet *pSnippet,             /* The Snippet object to be filled in */
  int iColumn,                   /* Index of fulltext table column */
  const char *zDoc,              /* Text of the fulltext table column */
  int nDoc                       /* Length of zDoc in bytes */
){
  const sqlite3_tokenizer_module *pTModule;  /* The tokenizer module */
  sqlite3_tokenizer *pTokenizer;             /* The specific tokenizer */
  sqlite3_tokenizer_cursor *pTCursor;        /* Tokenizer cursor */
  Fts3Table *pVtab;                /* The full text index */
  int nColumn;                         /* Number of columns in the index */
  int i, j;                            /* Loop counters */
  int rc;                              /* Return code */
  unsigned int match, prevMatch;       /* Phrase search bitmasks */
  const char *zToken;                  /* Next token from the tokenizer */
  int nToken;                          /* Size of zToken */
  int iBegin, iEnd, iPos;              /* Offsets of beginning and end */

  /* The following variables keep a circular buffer of the last
  ** few tokens */
  unsigned int iRotor = 0;             /* Index of current token */
  int iRotorBegin[FTS3_ROTOR_SZ];      /* Beginning offset of token */
  int iRotorLen[FTS3_ROTOR_SZ];        /* Length of token */

  pVtab =  (Fts3Table *)pCur->base.pVtab;
  nColumn = pVtab->nColumn;
  pTokenizer = pVtab->pTokenizer;
  pTModule = pTokenizer->pModule;
  rc = pTModule->xOpen(pTokenizer, zDoc, nDoc, &pTCursor);
  if( rc ) return rc;
  pTCursor->pTokenizer = pTokenizer;

  prevMatch = 0;
  while( (rc = pTModule->xNext(pTCursor, &zToken, &nToken,
                               &iBegin, &iEnd, &iPos))==SQLITE_OK ){
    Fts3Expr *pIter = pCur->pExpr;
    int iIter = -1;
    iRotorBegin[iRotor&FTS3_ROTOR_MASK] = iBegin;
    iRotorLen[iRotor&FTS3_ROTOR_MASK] = iEnd-iBegin;
    match = 0;
    for(i=0; i<(FTS3_ROTOR_SZ-1) && fts3NextExprToken(&pIter, &iIter); i++){
      int nPhrase;                    /* Number of tokens in current phrase */
      struct PhraseToken *pToken;     /* Current token */
      int iCol;                       /* Column index */

      if( fts3ExprBeneathNot(pIter) ) continue;
      nPhrase = pIter->pPhrase->nToken;
      pToken = &pIter->pPhrase->aToken[iIter];
      iCol = pIter->pPhrase->iColumn;
      if( iCol>=0 && iCol<nColumn && iCol!=iColumn ) continue;
      if( pToken->n>nToken ) continue;
      if( !pToken->isPrefix && pToken->n<nToken ) continue;
      assert( pToken->n<=nToken );
      if( memcmp(pToken->z, zToken, pToken->n) ) continue;
      if( iIter>0 && (prevMatch & (1<<i))==0 ) continue;
      match |= 1<<i;
      if( i==(FTS3_ROTOR_SZ-2) || nPhrase==iIter+1 ){
        for(j=nPhrase-1; j>=0; j--){
          int k = (iRotor-j) & FTS3_ROTOR_MASK;
          rc = snippetAppendMatch(pSnippet, iColumn, i-j, iPos-j,
                                  iRotorBegin[k], iRotorLen[k]);
          if( rc ) goto end_offsets_of_column;
        }
      }
    }
    prevMatch = match<<1;
    iRotor++;
  }
end_offsets_of_column:
  pTModule->xClose(pTCursor);  
  return rc==SQLITE_DONE ? SQLITE_OK : rc;
}

/*
** Remove entries from the pSnippet structure to account for the NEAR
** operator. When this is called, pSnippet contains the list of token 
** offsets produced by treating all NEAR operators as AND operators.
** This function removes any entries that should not be present after
** accounting for the NEAR restriction. For example, if the queried
** document is:
**
**     "A B C D E A"
**
** and the query is:
** 
**     A NEAR/0 E
**
** then when this function is called the Snippet contains token offsets
** 0, 4 and 5. This function removes the "0" entry (because the first A
** is not near enough to an E).
**
** When this function is called, the value pointed to by parameter piLeft is
** the integer id of the left-most token in the expression tree headed by
** pExpr. This function increments *piLeft by the total number of tokens
** in the expression tree headed by pExpr.
**
** Return 1 if any trimming occurs.  Return 0 if no trimming is required.
*/
static int trimSnippetOffsets(
  Fts3Expr *pExpr,      /* The search expression */
  Snippet *pSnippet,    /* The set of snippet offsets to be trimmed */
  int *piLeft           /* Index of left-most token in pExpr */
){
  if( pExpr ){
    if( trimSnippetOffsets(pExpr->pLeft, pSnippet, piLeft) ){
      return 1;
    }

    switch( pExpr->eType ){
      case FTSQUERY_PHRASE:
        *piLeft += pExpr->pPhrase->nToken;
        break;
      case FTSQUERY_NEAR: {
        /* The right-hand-side of a NEAR operator is always a phrase. The
        ** left-hand-side is either a phrase or an expression tree that is 
        ** itself headed by a NEAR operator. The following initializations
        ** set local variable iLeft to the token number of the left-most
        ** token in the right-hand phrase, and iRight to the right most
        ** token in the same phrase. For example, if we had:
        **
        **     <col> MATCH '"abc def" NEAR/2 "ghi jkl"'
        **
        ** then iLeft will be set to 2 (token number of ghi) and nToken will
        ** be set to 4.
        */
        Fts3Expr *pLeft = pExpr->pLeft;
        Fts3Expr *pRight = pExpr->pRight;
        int iLeft = *piLeft;
        int nNear = pExpr->nNear;
        int nToken = pRight->pPhrase->nToken;
        int jj, ii;
        if( pLeft->eType==FTSQUERY_NEAR ){
          pLeft = pLeft->pRight;
        }
        assert( pRight->eType==FTSQUERY_PHRASE );
        assert( pLeft->eType==FTSQUERY_PHRASE );
        nToken += pLeft->pPhrase->nToken;

        for(ii=0; ii<pSnippet->nMatch; ii++){
          struct snippetMatch *p = &pSnippet->aMatch[ii];
          if( p->iTerm==iLeft ){
            int isOk = 0;
            /* Snippet ii is an occurence of query term iLeft in the document.
            ** It occurs at position (p->iToken) of the document. We now
            ** search for an instance of token (iLeft-1) somewhere in the 
            ** range (p->iToken - nNear)...(p->iToken + nNear + nToken) within 
            ** the set of snippetMatch structures. If one is found, proceed. 
            ** If one cannot be found, then remove snippets ii..(ii+N-1) 
            ** from the matching snippets, where N is the number of tokens 
            ** in phrase pRight->pPhrase.
            */
            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
              if( p2->iTerm==(iLeft-1) ){
                if( p2->iToken>=(p->iToken-nNear-1) 
                 && p2->iToken<(p->iToken+nNear+nToken) 
                ){
                  isOk = 1;
                }
              }
            }
            if( !isOk ){
              int kk;
              for(kk=0; kk<pRight->pPhrase->nToken; kk++){
                pSnippet->aMatch[kk+ii].iTerm = -2;
              }
              return 1;
            }
          }
          if( p->iTerm==(iLeft-1) ){
            int isOk = 0;
            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
              if( p2->iTerm==iLeft ){
                if( p2->iToken<=(p->iToken+nNear+1) 
                 && p2->iToken>(p->iToken-nNear-nToken) 
                ){
                  isOk = 1;
                }
              }
            }
            if( !isOk ){
              int kk;
              for(kk=0; kk<pLeft->pPhrase->nToken; kk++){
                pSnippet->aMatch[ii-kk].iTerm = -2;
              }
              return 1;
            }
          }
        }
        break;
      }
    }

    if( trimSnippetOffsets(pExpr->pRight, pSnippet, piLeft) ){
      return 1;
    }
  }
  return 0;
}

/*
** Compute all offsets for the current row of the query.  
** If the offsets have already been computed, this routine is a no-op.
*/
static int snippetAllOffsets(Fts3Cursor *pCsr, Snippet **ppSnippet){
  Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;  /* The FTS3 virtual table */
  int nColumn;           /* Number of columns.  Docid does count */
  int iColumn;           /* Index of of a column */
  int i;                 /* Loop index */
  int iFirst;            /* First column to search */
  int iLast;             /* Last coumn to search */
  int iTerm = 0;
  Snippet *pSnippet;
  int rc = SQLITE_OK;

  if( pCsr->pExpr==0 ){
    return SQLITE_OK;
  }

  pSnippet = (Snippet *)sqlite3_malloc(sizeof(Snippet));
  *ppSnippet = pSnippet;
  if( !pSnippet ){
    return SQLITE_NOMEM;
  }
  memset(pSnippet, 0, sizeof(Snippet));

  nColumn = p->nColumn;
  iColumn = (pCsr->eSearch - 2);
  if( iColumn<0 || iColumn>=nColumn ){
    /* Look for matches over all columns of the full-text index */
    iFirst = 0;
    iLast = nColumn-1;
  }else{
    /* Look for matches in the iColumn-th column of the index only */
    iFirst = iColumn;
    iLast = iColumn;
  }
  for(i=iFirst; rc==SQLITE_OK && i<=iLast; i++){
    const char *zDoc;
    int nDoc;
    zDoc = (const char*)sqlite3_column_text(pCsr->pStmt, i+1);
    nDoc = sqlite3_column_bytes(pCsr->pStmt, i+1);
    if( zDoc==0 && sqlite3_column_type(pCsr->pStmt, i+1)!=SQLITE_NULL ){
      rc = SQLITE_NOMEM;
    }else{
      rc = snippetOffsetsOfColumn(pCsr, pSnippet, i, zDoc, nDoc);
    }
  }

  while( trimSnippetOffsets(pCsr->pExpr, pSnippet, &iTerm) ){
    iTerm = 0;
  }

  return rc;
}

/*
** Convert the information in the aMatch[] array of the snippet
** into the string zOffset[0..nOffset-1]. This string is used as
** the return of the SQL offsets() function.
*/
static void snippetOffsetText(Snippet *p){
  int i;
  int cnt = 0;
  StringBuffer sb;
  char zBuf[200];
  if( p->zOffset ) return;
  fts3SnippetSbInit(&sb);
  for(i=0; i<p->nMatch; i++){
    struct snippetMatch *pMatch = &p->aMatch[i];
    if( pMatch->iTerm>=0 ){
      /* If snippetMatch.iTerm is less than 0, then the match was 
      ** discarded as part of processing the NEAR operator (see the 
      ** trimSnippetOffsetsForNear() function for details). Ignore 
      ** it in this case
      */
      zBuf[0] = ' ';
      sqlite3_snprintf(sizeof(zBuf)-1, &zBuf[cnt>0], "%d %d %d %d",
          pMatch->iCol, pMatch->iTerm, pMatch->iStart, pMatch->nByte);
      fts3SnippetAppend(&sb, zBuf, -1);
      cnt++;
    }
  }
  p->zOffset = sb.z;
  p->nOffset = sb.z ? sb.nUsed : 0;
}

/*
** zDoc[0..nDoc-1] is phrase of text.  aMatch[0..nMatch-1] are a set
** of matching words some of which might be in zDoc.  zDoc is column
** number iCol.
**
** iBreak is suggested spot in zDoc where we could begin or end an
** excerpt.  Return a value similar to iBreak but possibly adjusted
** to be a little left or right so that the break point is better.
*/
static int wordBoundary(
  int iBreak,                   /* The suggested break point */
  const char *zDoc,             /* Document text */
  int nDoc,                     /* Number of bytes in zDoc[] */
  struct snippetMatch *aMatch,  /* Matching words */
  int nMatch,                   /* Number of entries in aMatch[] */
  int iCol                      /* The column number for zDoc[] */
){
  int i;
  if( iBreak<=10 ){
    return 0;
  }
  if( iBreak>=nDoc-10 ){
    return nDoc;
  }
  for(i=0; ALWAYS(i<nMatch) && aMatch[i].iCol<iCol; i++){}
  while( i<nMatch && aMatch[i].iStart+aMatch[i].nByte<iBreak ){ i++; }
  if( i<nMatch ){
    if( aMatch[i].iStart<iBreak+10 ){
      return aMatch[i].iStart;
    }
    if( i>0 && aMatch[i-1].iStart+aMatch[i-1].nByte>=iBreak ){
      return aMatch[i-1].iStart;
    }
  }
  for(i=1; i<=10; i++){
    if( fts3snippetIsspace(zDoc[iBreak-i]) ){
      return iBreak - i + 1;
    }
    if( fts3snippetIsspace(zDoc[iBreak+i]) ){
      return iBreak + i + 1;
    }
  }
  return iBreak;
}



/*
** Allowed values for Snippet.aMatch[].snStatus
*/
#define SNIPPET_IGNORE  0   /* It is ok to omit this match from the snippet */
#define SNIPPET_DESIRED 1   /* We want to include this match in the snippet */

/*
** Generate the text of a snippet.
*/
static void snippetText(
  Fts3Cursor *pCursor,   /* The cursor we need the snippet for */
  Snippet *pSnippet,
  const char *zStartMark,     /* Markup to appear before each match */
  const char *zEndMark,       /* Markup to appear after each match */
  const char *zEllipsis       /* Ellipsis mark */
){
  int i, j;
  struct snippetMatch *aMatch;
  int nMatch;
  int nDesired;
  StringBuffer sb;
  int tailCol;
  int tailOffset;
  int iCol;
  int nDoc;
  const char *zDoc;
  int iStart, iEnd;
  int tailEllipsis = 0;
  int iMatch;
  

  sqlite3_free(pSnippet->zSnippet);
  pSnippet->zSnippet = 0;
  aMatch = pSnippet->aMatch;
  nMatch = pSnippet->nMatch;
  fts3SnippetSbInit(&sb);

  for(i=0; i<nMatch; i++){
    aMatch[i].snStatus = SNIPPET_IGNORE;
  }
  nDesired = 0;
  for(i=0; i<FTS3_ROTOR_SZ; i++){
    for(j=0; j<nMatch; j++){
      if( aMatch[j].iTerm==i ){
        aMatch[j].snStatus = SNIPPET_DESIRED;
        nDesired++;
        break;
      }
    }
  }

  iMatch = 0;
  tailCol = -1;
  tailOffset = 0;
  for(i=0; i<nMatch && nDesired>0; i++){
    if( aMatch[i].snStatus!=SNIPPET_DESIRED ) continue;
    nDesired--;
    iCol = aMatch[i].iCol;
    zDoc = (const char*)sqlite3_column_text(pCursor->pStmt, iCol+1);
    nDoc = sqlite3_column_bytes(pCursor->pStmt, iCol+1);
    iStart = aMatch[i].iStart - 40;
    iStart = wordBoundary(iStart, zDoc, nDoc, aMatch, nMatch, iCol);
    if( iStart<=10 ){
      iStart = 0;
    }
    if( iCol==tailCol && iStart<=tailOffset+20 ){
      iStart = tailOffset;
    }
    if( (iCol!=tailCol && tailCol>=0) || iStart!=tailOffset ){
      fts3SnippetTrimWhiteSpace(&sb);
      fts3SnippetAppendWhiteSpace(&sb);
      fts3SnippetAppend(&sb, zEllipsis, -1);
      fts3SnippetAppendWhiteSpace(&sb);
    }
    iEnd = aMatch[i].iStart + aMatch[i].nByte + 40;
    iEnd = wordBoundary(iEnd, zDoc, nDoc, aMatch, nMatch, iCol);
    if( iEnd>=nDoc-10 ){
      iEnd = nDoc;
      tailEllipsis = 0;
    }else{
      tailEllipsis = 1;
    }
    while( iMatch<nMatch && aMatch[iMatch].iCol<iCol ){ iMatch++; }
    while( iStart<iEnd ){
      while( iMatch<nMatch && aMatch[iMatch].iStart<iStart
             && aMatch[iMatch].iCol<=iCol ){
        iMatch++;
      }
      if( iMatch<nMatch && aMatch[iMatch].iStart<iEnd
             && aMatch[iMatch].iCol==iCol ){
        fts3SnippetAppend(&sb, &zDoc[iStart], aMatch[iMatch].iStart - iStart);
        iStart = aMatch[iMatch].iStart;
        fts3SnippetAppend(&sb, zStartMark, -1);
        fts3SnippetAppend(&sb, &zDoc[iStart], aMatch[iMatch].nByte);
        fts3SnippetAppend(&sb, zEndMark, -1);
        iStart += aMatch[iMatch].nByte;
        for(j=iMatch+1; j<nMatch; j++){
          if( aMatch[j].iTerm==aMatch[iMatch].iTerm
              && aMatch[j].snStatus==SNIPPET_DESIRED ){
            nDesired--;
            aMatch[j].snStatus = SNIPPET_IGNORE;
          }
        }
      }else{
        fts3SnippetAppend(&sb, &zDoc[iStart], iEnd - iStart);
        iStart = iEnd;
      }
    }
    tailCol = iCol;
    tailOffset = iEnd;
  }
  fts3SnippetTrimWhiteSpace(&sb);
  if( tailEllipsis ){
    fts3SnippetAppendWhiteSpace(&sb);
    fts3SnippetAppend(&sb, zEllipsis, -1);
  }
  pSnippet->zSnippet = sb.z;
  pSnippet->nSnippet = sb.z ? sb.nUsed : 0;
}

void sqlite3Fts3Offsets(
  sqlite3_context *pCtx,          /* SQLite function call context */
  Fts3Cursor *pCsr                /* Cursor object */
){
  Snippet *p;                     /* Snippet structure */
  int rc = snippetAllOffsets(pCsr, &p);
  if( rc==SQLITE_OK ){
    snippetOffsetText(p);
    if( p->zOffset ){
      sqlite3_result_text(pCtx, p->zOffset, p->nOffset, SQLITE_TRANSIENT);
    }else{
      sqlite3_result_error_nomem(pCtx);
    }
  }else{
    sqlite3_result_error_nomem(pCtx);
  }
  fts3SnippetFree(p);
}

void sqlite3Fts3Snippet(
  sqlite3_context *pCtx,          /* SQLite function call context */
  Fts3Cursor *pCsr,               /* Cursor object */
  const char *zStart,             /* Snippet start text - "<b>" */
  const char *zEnd,               /* Snippet end text - "</b>" */
  const char *zEllipsis           /* Snippet ellipsis text - "<b>...</b>" */
){
  Snippet *p;                     /* Snippet structure */
  int rc = snippetAllOffsets(pCsr, &p);
  if( rc==SQLITE_OK ){
    snippetText(pCsr, p, zStart, zEnd, zEllipsis);
    if( p->zSnippet ){
      sqlite3_result_text(pCtx, p->zSnippet, p->nSnippet, SQLITE_TRANSIENT);
    }else{
      sqlite3_result_error_nomem(pCtx);
    }
  }else{
    sqlite3_result_error_nomem(pCtx);
  }
  fts3SnippetFree(p);
}

/*************************************************************************
** Below this point is the alternative, experimental snippet() implementation.
*/

#define SNIPPET_BUFFER_CHUNK  64
#define SNIPPET_BUFFER_SIZE   SNIPPET_BUFFER_CHUNK*4
#define SNIPPET_BUFFER_MASK   (SNIPPET_BUFFER_SIZE-1)

static void fts3GetDeltaPosition(char **pp, int *piPos){
  int iVal;
  *pp += sqlite3Fts3GetVarint32(*pp, &iVal);

  return rc;
}

typedef struct LoadDoclistCtx LoadDoclistCtx;
struct LoadDoclistCtx {
  Fts3Table *pTab;                /* FTS3 Table */
  int nPhrase;                    /* Number of phrases so far */

};
































static int fts3ExprLoadDoclistsCb(Fts3Expr *pExpr, void *ctx){
  int rc = SQLITE_OK;
  LoadDoclistCtx *p = (LoadDoclistCtx *)ctx;

  p->nPhrase++;


  if( pExpr->isLoaded==0 ){
    rc = sqlite3Fts3ExprLoadDoclist(p->pTab, pExpr);
    pExpr->isLoaded = 1;
    if( rc==SQLITE_OK && pExpr->aDoclist ){
      pExpr->pCurrent = pExpr->aDoclist;
      pExpr->pCurrent += sqlite3Fts3GetVarint(pExpr->pCurrent,&pExpr->iCurrent);
    }
  }

  return rc;
}










static int fts3ExprLoadDoclists(Fts3Cursor *pCsr, int *pnPhrase){




  int rc;
  LoadDoclistCtx sCtx = {0, 0};
  sCtx.pTab = (Fts3Table *)pCsr->base.pVtab;
  rc = fts3ExprIterate(pCsr->pExpr, fts3ExprLoadDoclistsCb, (void *)&sCtx);



  *pnPhrase = sCtx.nPhrase;

  return rc;
}

/*
** Each call to this function populates a chunk of a snippet-buffer 
** SNIPPET_BUFFER_CHUNK bytes in size.
**

  memset(&aBuffer[iPos&SNIPPET_BUFFER_MASK], 0, SNIPPET_BUFFER_CHUNK);

  for(i=0; i<nList; i++){
    int iPrev = aiPrev[i];
    char *pList = apList[i];

    if( !pList ){
      nFin++;
      continue;
    }

    while( iPrev<(iPos+SNIPPET_BUFFER_CHUNK) ){
      if( iPrev>=iPos ){
        aBuffer[iPrev&SNIPPET_BUFFER_MASK] = (u8)(i+1);
      }
      if( 0==((*pList)&0xFE) ){
        nFin++;
        break;
      }
      fts3GetDeltaPosition(&pList, &iPrev); 

    }

    aiPrev[i] = iPrev;
    apList[i] = pList;
  }

  return (nFin==nList);

  int *anCnt, 
  u8 *aBuffer,
  int *anToken,
  u64 *pHlmask
){
  int iSub =  (iIdx-1)&SNIPPET_BUFFER_MASK;
  int iAdd =  (iIdx+nSnippet-1)&SNIPPET_BUFFER_MASK;
  int iSub2 = (iIdx+(nSnippet/3)-1)&SNIPPET_BUFFER_MASK;
  int iAdd2 = (iIdx+(nSnippet*2/3)-1)&SNIPPET_BUFFER_MASK;

  u64 h = *pHlmask;

  anCnt[ aBuffer[iSub]  ]--;
  anCnt[ aBuffer[iSub2] ]--;
  anCnt[ aBuffer[iAdd]  ]++;
  anCnt[ aBuffer[iAdd2] ]++;

  h = h >> 1;
  if( aBuffer[iAdd] ){
    int j;
    for(j=anToken[aBuffer[iAdd]-1]; j>=1; j--){
      h |= (u64)1 << (nSnippet-j);
    }
  }
  *pHlmask = h;
}

static int fts3SnippetScore(int n, int *anCnt){
  int j;
  int iScore = 0;
  for(j=1; j<=n; j++){
    int nCnt = anCnt[j];
    iScore += nCnt + (nCnt ? 1000 : 0);


  }

  return iScore;
}




















static int fts3BestSnippet(
  int nSnippet,                   /* Desired snippet length */
  Fts3Cursor *pCsr,               /* Cursor to create snippet for */
  int iCol,                       /* Index of column to create snippet from */

  int *piPos,                     /* OUT: Starting token for best snippet */
  u64 *pHlmask                    /* OUT: Highlight mask for best snippet */

){
  int rc;                         /* Return Code */
  u8 aBuffer[SNIPPET_BUFFER_SIZE];/* Circular snippet buffer */
  int *aiPrev;                    /* Used by fts3LoadSnippetBuffer() */
  int *anToken;                   /* Number of tokens in each phrase */
  char **apList;                  /* Array of position lists */
  int *anCnt;                     /* Running totals of phrase occurences */
  int nList;

  int i;

  u64 hlmask = 0;                 /* Current mask of highlighted terms */
  u64 besthlmask = 0;             /* Mask of highlighted terms for iBestPos */

  int iBestPos = 0;               /* Starting position of 'best' snippet */
  int iBestScore = 0;             /* Score of best snippet higher->better */

  SnippetCtx sCtx;

  /* Iterate through the phrases in the expression to count them. The same
  ** callback makes sure the doclists are loaded for each phrase.
  */
  rc = fts3ExprLoadDoclists(pCsr, &nList);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  /* Now that it is known how many phrases there are, allocate and zero
  ** the required arrays using malloc().
  */
  apList = sqlite3_malloc(
      sizeof(u8*)*nList +         /* apList */
      sizeof(int)*(nList) +       /* anToken */
      sizeof(int)*nList +         /* aiPrev */
      sizeof(int)*(nList+1)       /* anCnt */
  );

  if( !apList ){
    return SQLITE_NOMEM;
  }
  memset(apList, 0, sizeof(u8*)*nList+sizeof(int)*nList+sizeof(int)*nList);
  anToken = (int *)&apList[nList];
  aiPrev = &anToken[nList];
  anCnt = &aiPrev[nList];

  /* Initialize the contents of the aiPrev and aiList arrays. */
  sCtx.pCsr = pCsr;
  sCtx.iCol = iCol;
  sCtx.apList = apList;
  sCtx.aiPrev = aiPrev;
  sCtx.anToken = anToken;
  sCtx.iPhrase = 0;
  (void)fts3ExprIterate(pCsr->pExpr, fts3SnippetFindPositions, (void *)&sCtx);







  /* Load the first two chunks of data into the buffer. */
  memset(aBuffer, 0, SNIPPET_BUFFER_SIZE);
  fts3LoadSnippetBuffer(0, aBuffer, nList, apList, aiPrev);
  fts3LoadSnippetBuffer(SNIPPET_BUFFER_CHUNK, aBuffer, nList, apList, aiPrev);

  /* Set the initial contents of the highlight-mask and anCnt[] array. */
  for(i=1-nSnippet; i<=0; i++){
    fts3SnippetCnt(i, nSnippet, anCnt, aBuffer, anToken, &hlmask);
  }
  iBestScore = fts3SnippetScore(nList, anCnt);
  besthlmask = hlmask;
  iBestPos = 0;


  for(i=1; 1; i++){
    int iScore;

    if( 0==(i&(SNIPPET_BUFFER_CHUNK-1)) ){
      int iLoad = i + SNIPPET_BUFFER_CHUNK;
      if( fts3LoadSnippetBuffer(iLoad, aBuffer, nList, apList, aiPrev) ) break;


    }

    /* Figure out how highly a snippet starting at token offset i scores
    ** according to fts3SnippetScore(). If it is higher than any previously
    ** considered position, save the current position, score and hlmask as 
    ** the best snippet candidate found so far.
    */
    fts3SnippetCnt(i, nSnippet, anCnt, aBuffer, anToken, &hlmask);
    iScore = fts3SnippetScore(nList, anCnt);
    if( iScore>iBestScore ){
      iBestPos = i;
      iBestScore = iScore;
      besthlmask = hlmask;

    }
  }

  sqlite3_free(apList);

  *piPos = iBestPos;
  *pHlmask = besthlmask;



  return SQLITE_OK;
}

typedef struct StrBuffer StrBuffer;
struct StrBuffer {
  char *z;
  int n;
  int nAlloc;
};

static int fts3StringAppend(
  StrBuffer *pStr, 
  const char *zAppend, 
  int nAppend
){
  if( nAppend<0 ){
    nAppend = (int)strlen(zAppend);
  }

  if( pStr->n+nAppend+1>=pStr->nAlloc ){
    int nAlloc = pStr->nAlloc+nAppend+100;
    char *zNew = sqlite3_realloc(pStr->z, nAlloc);
    if( !zNew ){
      return SQLITE_NOMEM;
    }
    pStr->z = zNew;
    pStr->nAlloc = nAlloc;
  }

  memcpy(&pStr->z[pStr->n], zAppend, nAppend);
  pStr->n += nAppend;
  pStr->z[pStr->n] = '\0';

  return SQLITE_OK;
}
















































static int fts3SnippetText(
  Fts3Cursor *pCsr,               /* FTS3 Cursor */
  const char *zDoc,               /* Document to extract snippet from */
  int nDoc,                       /* Size of zDoc in bytes */
  int nSnippet,                   /* Number of tokens in extracted snippet */
  int iPos,                       /* Index of first document token in snippet */
  u64 hlmask,                     /* Bitmask of terms to highlight in snippet */
  const char *zOpen,              /* String inserted before highlighted term */
  const char *zClose,             /* String inserted after highlighted term */
  const char *zEllipsis,
  char **pzSnippet                /* OUT: Snippet text */
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int rc;                         /* Return code */


  int iCurrent = 0;
  int iStart = 0;

  int iEnd;



  sqlite3_tokenizer_module *pMod; /* Tokenizer module methods object */
  sqlite3_tokenizer_cursor *pC;   /* Tokenizer cursor open on zDoc/nDoc */
  const char *ZDUMMY;             /* Dummy arguments used with tokenizer */
  int DUMMY1, DUMMY2, DUMMY3;     /* Dummy arguments used with tokenizer */

  StrBuffer res = {0, 0, 0};   /* Result string */








  /* Open a token cursor on the document. Read all tokens up to and 
  ** including token iPos (the first token of the snippet). Set variable
  ** iStart to the byte offset in zDoc of the start of token iPos.
  */
  pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
  rc = pMod->xOpen(pTab->pTokenizer, zDoc, nDoc, &pC);
  while( rc==SQLITE_OK && iCurrent<iPos ){
    rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &iStart, &DUMMY2, &iCurrent);
  }
  iEnd = iStart;

  if( rc==SQLITE_OK && iStart>0 ){
    rc = fts3StringAppend(&res, zEllipsis, -1);
  }

  while( rc==SQLITE_OK ){
    int iBegin;
    int iFin;
    rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &iBegin, &iFin, &iCurrent);

    if( rc==SQLITE_OK ){











      if( iCurrent>=(iPos+nSnippet) ){
        rc = SQLITE_DONE;
      }else{
        iEnd = iFin;
        if( hlmask & ((u64)1 << (iCurrent-iPos)) ){
          if( fts3StringAppend(&res, &zDoc[iStart], iBegin-iStart)
           || fts3StringAppend(&res, zOpen, -1)
           || fts3StringAppend(&res, &zDoc[iBegin], iEnd-iBegin)
           || fts3StringAppend(&res, zClose, -1)
          ){
            rc = SQLITE_NOMEM;
          }
          iStart = iEnd;
        }
      }
    }
  }
  assert( rc!=SQLITE_OK );
  if( rc==SQLITE_DONE ){
    rc = fts3StringAppend(&res, &zDoc[iStart], iEnd-iStart);
    if( rc==SQLITE_OK ){
      rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &DUMMY2, &DUMMY3, &iCurrent);
      if( rc==SQLITE_OK ){
        rc = fts3StringAppend(&res, zEllipsis, -1);
      }else if( rc==SQLITE_DONE ){
        rc = fts3StringAppend(&res, &zDoc[iEnd], -1);
      }
    }
  }

  pMod->xClose(pC);
  if( rc!=SQLITE_OK ){
    sqlite3_free(res.z);
  }else{
    *pzSnippet = res.z;
  }
  return rc;
}


/*
** An instance of this structure is used to collect the 'global' part of
** the matchinfo statistics. The 'global' part consists of the following:

    int rc;
    int nPhrase;
    int nMatchinfo;

    g.pTab = pTab;
    g.nCol = pTab->nColumn;
    g.iPhrase = 0;
    rc = fts3ExprLoadDoclists(pCsr, &nPhrase);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    nMatchinfo = 2 + 2*g.nCol*nPhrase;

    g.iPhrase = 0;

    (void)fts3ExprIterate(pCsr->pExpr, fts3ExprLocalMatchinfoCb, (void *)&g);
    pCsr->isMatchinfoOk = 0;
  }

  return SQLITE_OK;
}

void sqlite3Fts3Snippet2(
  sqlite3_context *pCtx,          /* SQLite function call context */
  Fts3Cursor *pCsr,               /* Cursor object */
  const char *zStart,             /* Snippet start text - "<b>" */
  const char *zEnd,               /* Snippet end text - "</b>" */
  const char *zEllipsis,          /* Snippet ellipsis text - "<b>...</b>" */
  int iCol,                       /* Extract snippet from this column */
  int nToken                      /* Approximate number of tokens in snippet */
){

  int rc;
  int iPos = 0;

  u64 hlmask = 0;











  char *z = 0;





















  int nDoc;

  const char *zDoc;










  rc = fts3BestSnippet(nToken, pCsr, iCol, &iPos, &hlmask);


  nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol+1);






  zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol+1);


  if( rc==SQLITE_OK ){






    rc = fts3SnippetText(
        pCsr, zDoc, nDoc, nToken, iPos, hlmask, zStart, zEnd, zEllipsis, &z);
  }


  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pCtx, rc);

  }else{
    sqlite3_result_text(pCtx, z, -1, sqlite3_free);
  }


























































































































































}

void sqlite3Fts3Matchinfo(sqlite3_context *pContext, Fts3Cursor *pCsr){
  int rc = fts3GetMatchinfo(pCsr);
  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pContext, rc);
  }else{
    int n = sizeof(u32)*(2+pCsr->aMatchinfo[0]*pCsr->aMatchinfo[1]*2);
    sqlite3_result_blob(pContext, pCsr->aMatchinfo, n, SQLITE_TRANSIENT);
  }
}

#endif

  }
} {{Alert Posted 10:00 AM November 20,2000: E-<b>GAS</b> Request <b>Reminder</b>}}
do_test fts3ac-4.2 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'christmas candlelight'
  }
} {{<b>...</b> place.? What do you think about going here <b>Christmas</b> 
eve?? They have an 11:00 a.m. service and a <b>candlelight</b> service at 5:00 p.m., 
among others. <b>...</b>}}

do_test fts3ac-4.3 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'deal sheet potential reuse'
  }
} {{EOL-Accenture <b>Deal</b> <b>Sheet</b> <b>...</b> intent
     Review Enron asset base for <b>potential</b> <b>reuse</b>/ licensing
     Contract negotiations <b>...</b>}}
do_test fts3ac-4.4 {
  execsql {
    SELECT snippet(email,'<<<','>>>',' ') FROM email
     WHERE email MATCH 'deal sheet potential reuse'
  }
} {{EOL-Accenture <<<Deal>>> <<<Sheet>>>  intent
     Review Enron asset base for <<<potential>>> <<<reuse>>>/ licensing
     Contract negotiations  }}
do_test fts3ac-4.5 {
  execsql {
    SELECT snippet(email,'<<<','>>>',' ') FROM email
     WHERE email MATCH 'first things'
  }
} {{Re: <<<First>>> Polish Deal!  Congrats!  <<<Things>>> seem to be building rapidly now on the  }}
do_test fts3ac-4.6 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'chris is here'
  }
} {{<b>chris</b>.germany@enron.com <b>...</b> Sounds good to me.  I bet this <b>is</b> next to the Warick?? Hotel. <b>...</b> place.? What do you think about going <b>here</b> Christmas 
eve?? They have an 11:00 a.m. <b>...</b>}}
do_test fts3ac-4.7 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH '"pursuant to"'
  }
} {{Erin:

<b>Pursuant</b> <b>to</b> your request, attached are the Schedule to <b>...</b>}}
do_test fts3ac-4.8 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'ancillary load davis'
  }
} {{pete.<b>davis</b>@enron.com <b>...</b> Start Date: 4/22/01; HourAhead hour: 3;  No <b>ancillary</b> schedules awarded.  
Variances detected.
Variances detected in <b>Load</b> schedule.

    LOG MESSAGES:

PARSING <b>...</b>}}

# Combinations of AND and OR operators:
#
do_test fts3ac-5.1 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'questar enron OR com'
  }
} {{matt.smith@<b>enron</b>.<b>com</b> <b>...</b> six reports:  

31 Keystone Receipts
15 <b>Questar</b> Pipeline
40 Rockies Production
22 West_2 <b>...</b>}}
do_test fts3ac-5.2 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'enron OR com questar'
  }
} {{matt.smith@<b>enron</b>.<b>com</b> <b>...</b> six reports:  

31 Keystone Receipts
15 <b>Questar</b> Pipeline
40 Rockies Production
22 West_2 <b>...</b>}}

finish_test

# exercised.  The version with a couple extra spaces should cause the
# other isspace() call to be exercised.  [Both cases have been tested
# in the debugger, but I'm hoping to continue to catch it if simple
# constant changes change things slightly.
#
# The trailing and leading hi-bit chars help with code which tests for
# isspace() to coalesce multiple spaces.





set word "\x80xxxxx\x80xxxxx\x80xxxxx\x80xxxxx\x80xxxxx\x80xxxxx\x80"
set phrase1 "$word $word $word target $word $word $word"
set phrase2 "$word $word $word    target    $word $word $word"

db eval {CREATE VIRTUAL TABLE t4 USING fts3(content)}
db eval "INSERT INTO t4 (content) VALUES ('$phrase1')"
db eval "INSERT INTO t4 (content) VALUES ('$phrase2')"

do_test fts3al-1.4 {
  execsql {SELECT rowid, length(snippet(t4)) FROM t4 WHERE t4 MATCH 'target'}
} {1 111 2 117}

finish_test

do_test fts3near-1.14 {
  execsql {SELECT docid FROM t1 WHERE content MATCH 'four NEAR four'}
} {} 
do_test fts3near-1.15 {
  execsql {SELECT docid FROM t1 WHERE content MATCH 'one NEAR two NEAR one'}
} {3} 













# Output format of the offsets() function:
#
#     <column number> <term number> <starting offset> <number of bytes>
#
db eval {
  INSERT INTO t1(content) VALUES('A X B C D A B');

  execsql {SELECT offsets(t1) FROM t1 WHERE content MATCH 'two NEAR/2 three'}
} {{0 0 4 3 0 1 8 5 0 0 14 3 0 1 27 5}}
do_test fts3near-3.6 {
  execsql {
    SELECT offsets(t1) FROM t1 WHERE content MATCH 'three NEAR/0 "two four"'
  }
} {{0 0 8 5 0 1 14 3 0 2 18 4}}

do_test fts3near-3.7 {
  execsql {
    SELECT offsets(t1) FROM t1 WHERE content MATCH '"two four" NEAR/0 three'}
} {{0 2 8 5 0 0 14 3 0 1 18 4}}

db eval {
  INSERT INTO t1(content) VALUES('
    This specification defines Cascading Style Sheets, level 2 (CSS2). CSS2 is a style sheet language that allows authors and users to attach style (e.g., fonts, spacing, and aural cues) to structured documents (e.g., HTML documents and XML applications). By separating the presentation style of documents from the content of documents, CSS2 simplifies Web authoring and site maintenance.

    CSS2 builds on CSS1 (see [CSS1]) and, with very few exceptions, all valid CSS1 style sheets are valid CSS2 style sheets. CSS2 supports media-specific style sheets so that authors may tailor the presentation of their documents to visual browsers, aural devices, printers, braille devices, handheld devices, etc. This specification also supports content positioning, downloadable fonts, table layout, features for internationalization, automatic counters and numbering, and some properties related to user interface.
  ') 
}
do_test fts3near-4.1 {
  execsql {
    SELECT snippet(t1) FROM t1 WHERE content MATCH 'specification NEAR supports'
  }
} {{<b>...</b> devices, handheld devices, etc. This <b>specification</b> also <b>supports</b> content positioning, downloadable fonts, <b>...</b>}}

do_test fts3near-5.1 {
  execsql {
    SELECT docid FROM t1 WHERE content MATCH 'specification attach'
  }
} {2}
do_test fts3near-5.2 {