Move bundled copy of sqlite one level deeper to better separate it...

third_party/sqlite/ext/fts1/fts1.c

-/* fts1 has a design flaw which can lead to database corruption (see
-** below).  It is recommended not to use it any longer, instead use
-** fts3 (or higher).  If you believe that your use of fts1 is safe,
-** add -DSQLITE_ENABLE_BROKEN_FTS1=1 to your CFLAGS.
-*/
-#if (!defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS1)) \
-        && !defined(SQLITE_ENABLE_BROKEN_FTS1)
-#error fts1 has a design flaw and has been deprecated.
-#endif
-/* The flaw is that fts1 uses the content table's unaliased rowid as
-** the unique docid.  fts1 embeds the rowid in the index it builds,
-** and expects the rowid to not change.  The SQLite VACUUM operation
-** will renumber such rowids, thereby breaking fts1.  If you are using
-** fts1 in a system which has disabled VACUUM, then you can continue
-** to use it safely.  Note that PRAGMA auto_vacuum does NOT disable
-** VACUUM, though systems using auto_vacuum are unlikely to invoke
-** VACUUM.
-**
-** fts1 should be safe even across VACUUM if you only insert documents
-** and never delete.
-*/
-
-/* The author disclaims copyright to this source code.
- *
- * This is an SQLite module implementing full-text search.
- */
-
-/*
-** The code in this file is only compiled if:
-**
-**     * The FTS1 module is being built as an extension
-**       (in which case SQLITE_CORE is not defined), or
-**
-**     * The FTS1 module is being built into the core of
-**       SQLite (in which case SQLITE_ENABLE_FTS1 is defined).
-*/
-#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS1)
-
-#if defined(SQLITE_ENABLE_FTS1) && !defined(SQLITE_CORE)
-# define SQLITE_CORE 1
-#endif
-
-#include <assert.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-#include <ctype.h>
-
-#include "fts1.h"
-#include "fts1_hash.h"
-#include "fts1_tokenizer.h"
-#include "sqlite3.h"
-#include "sqlite3ext.h"
-SQLITE_EXTENSION_INIT1
-
-
-#if 0
-# define TRACE(A)  printf A; fflush(stdout)
-#else
-# define TRACE(A)
-#endif
-
-/* utility functions */
-
-typedef struct StringBuffer {
-  int len;      /* length, not including null terminator */
-  int alloced;  /* Space allocated for s[] */ 
-  char *s;      /* Content of the string */
-} StringBuffer;
-
-static void initStringBuffer(StringBuffer *sb){
-  sb->len = 0;
-  sb->alloced = 100;
-  sb->s = malloc(100);
-  sb->s[0] = '\0';
-}
-
-static void nappend(StringBuffer *sb, const char *zFrom, int nFrom){
-  if( sb->len + nFrom >= sb->alloced ){
-    sb->alloced = sb->len + nFrom + 100;
-    sb->s = realloc(sb->s, sb->alloced+1);
-    if( sb->s==0 ){
-      initStringBuffer(sb);
-      return;
-    }
-  }
-  memcpy(sb->s + sb->len, zFrom, nFrom);
-  sb->len += nFrom;
-  sb->s[sb->len] = 0;
-}
-static void append(StringBuffer *sb, const char *zFrom){
-  nappend(sb, zFrom, strlen(zFrom));
-}
-
-/* We encode variable-length integers in little-endian order using seven bits
- * per byte as follows:
-**
-** KEY:
-**         A = 0xxxxxxx    7 bits of data and one flag bit
-**         B = 1xxxxxxx    7 bits of data and one flag bit
-**
-**  7 bits - A
-** 14 bits - BA
-** 21 bits - BBA
-** and so on.
-*/
-
-/* We may need up to VARINT_MAX bytes to store an encoded 64-bit integer. */
-#define VARINT_MAX 10
-
-/* Write a 64-bit variable-length integer to memory starting at p[0].
- * The length of data written will be between 1 and VARINT_MAX bytes.
- * The number of bytes written is returned. */
-static int putVarint(char *p, sqlite_int64 v){
-  unsigned char *q = (unsigned char *) p;
-  sqlite_uint64 vu = v;
-  do{
-    *q++ = (unsigned char) ((vu & 0x7f) | 0x80);
-    vu >>= 7;
-  }while( vu!=0 );
-  q[-1] &= 0x7f;  /* turn off high bit in final byte */
-  assert( q - (unsigned char *)p <= VARINT_MAX );
-  return (int) (q - (unsigned char *)p);
-}
-
-/* Read a 64-bit variable-length integer from memory starting at p[0].
- * Return the number of bytes read, or 0 on error.
- * The value is stored in *v. */
-static int getVarint(const char *p, sqlite_int64 *v){
-  const unsigned char *q = (const unsigned char *) p;
-  sqlite_uint64 x = 0, y = 1;
-  while( (*q & 0x80) == 0x80 ){
-    x += y * (*q++ & 0x7f);
-    y <<= 7;
-    if( q - (unsigned char *)p >= VARINT_MAX ){  /* bad data */
-      assert( 0 );
-      return 0;
-    }
-  }
-  x += y * (*q++);
-  *v = (sqlite_int64) x;
-  return (int) (q - (unsigned char *)p);
-}
-
-static int getVarint32(const char *p, int *pi){
- sqlite_int64 i;
- int ret = getVarint(p, &i);
- *pi = (int) i;
- assert( *pi==i );
- return ret;
-}
-
-/*** Document lists ***
- *
- * A document list holds a sorted list of varint-encoded document IDs.
- *
- * A doclist with type DL_POSITIONS_OFFSETS is stored like this:
- *
- * array {
- *   varint docid;
- *   array {
- *     varint position;     (delta from previous position plus POS_BASE)
- *     varint startOffset;  (delta from previous startOffset)
- *     varint endOffset;    (delta from startOffset)
- *   }
- * }
- *
- * Here, array { X } means zero or more occurrences of X, adjacent in memory.
- *
- * A position list may hold positions for text in multiple columns.  A position
- * POS_COLUMN is followed by a varint containing the index of the column for
- * following positions in the list.  Any positions appearing before any
- * occurrences of POS_COLUMN are for column 0.
- *
- * A doclist with type DL_POSITIONS is like the above, but holds only docids
- * and positions without offset information.
- *
- * A doclist with type DL_DOCIDS is like the above, but holds only docids
- * without positions or offset information.
- *
- * On disk, every document list has positions and offsets, so we don't bother
- * to serialize a doclist's type.
- * 
- * We don't yet delta-encode document IDs; doing so will probably be a
- * modest win.
- *
- * NOTE(shess) I've thought of a slightly (1%) better offset encoding.
- * After the first offset, estimate the next offset by using the
- * current token position and the previous token position and offset,
- * offset to handle some variance.  So the estimate would be
- * (iPosition*w->iStartOffset/w->iPosition-64), which is delta-encoded
- * as normal.  Offsets more than 64 chars from the estimate are
- * encoded as the delta to the previous start offset + 128.  An
- * additional tiny increment can be gained by using the end offset of
- * the previous token to make the estimate a tiny bit more precise.
-*/
-
-/* It is not safe to call isspace(), tolower(), or isalnum() on
-** hi-bit-set characters.  This is the same solution used in the
-** tokenizer.
-*/
-/* TODO(shess) The snippet-generation code should be using the
-** tokenizer-generated tokens rather than doing its own local
-** tokenization.
-*/
-/* TODO(shess) Is __isascii() a portable version of (c&0x80)==0? */
-static int safe_isspace(char c){
-  return (c&0x80)==0 ? isspace(c) : 0;
-}
-static int safe_tolower(char c){
-  return (c>='A' && c<='Z') ? (c-'A'+'a') : c;
-}
-static int safe_isalnum(char c){
-  return (c&0x80)==0 ? isalnum(c) : 0;
-}
-
-typedef enum DocListType {
-  DL_DOCIDS,              /* docids only */
-  DL_POSITIONS,           /* docids + positions */
-  DL_POSITIONS_OFFSETS    /* docids + positions + offsets */
-} DocListType;
-
-/*
-** By default, only positions and not offsets are stored in the doclists.
-** To change this so that offsets are stored too, compile with
-**
-**          -DDL_DEFAULT=DL_POSITIONS_OFFSETS
-**
-*/
-#ifndef DL_DEFAULT
-# define DL_DEFAULT DL_POSITIONS
-#endif
-
-typedef struct DocList {
-  char *pData;
-  int nData;
-  DocListType iType;
-  int iLastColumn;    /* the last column written */
-  int iLastPos;       /* the last position written */
-  int iLastOffset;    /* the last start offset written */
-} DocList;
-
-enum {
-  POS_END = 0,        /* end of this position list */
-  POS_COLUMN,         /* followed by new column number */
-  POS_BASE
-};
-
-/* Initialize a new DocList to hold the given data. */
-static void docListInit(DocList *d, DocListType iType,
-                        const char *pData, int nData){
-  d->nData = nData;
-  if( nData>0 ){
-    d->pData = malloc(nData);
-    memcpy(d->pData, pData, nData);
-  } else {
-    d->pData = NULL;
-  }
-  d->iType = iType;
-  d->iLastColumn = 0;
-  d->iLastPos = d->iLastOffset = 0;
-}
-
-/* Create a new dynamically-allocated DocList. */
-static DocList *docListNew(DocListType iType){
-  DocList *d = (DocList *) malloc(sizeof(DocList));
-  docListInit(d, iType, 0, 0);
-  return d;
-}
-
-static void docListDestroy(DocList *d){
-  free(d->pData);
-#ifndef NDEBUG
-  memset(d, 0x55, sizeof(*d));
-#endif
-}
-
-static void docListDelete(DocList *d){
-  docListDestroy(d);
-  free(d);
-}
-
-static char *docListEnd(DocList *d){
-  return d->pData + d->nData;
-}
-
-/* Append a varint to a DocList's data. */
-static void appendVarint(DocList *d, sqlite_int64 i){
-  char c[VARINT_MAX];
-  int n = putVarint(c, i);
-  d->pData = realloc(d->pData, d->nData + n);
-  memcpy(d->pData + d->nData, c, n);
-  d->nData += n;
-}
-
-static void docListAddDocid(DocList *d, sqlite_int64 iDocid){
-  appendVarint(d, iDocid);
-  if( d->iType>=DL_POSITIONS ){
-    appendVarint(d, POS_END);  /* initially empty position list */
-    d->iLastColumn = 0;
-    d->iLastPos = d->iLastOffset = 0;
-  }
-}
-
-/* helper function for docListAddPos and docListAddPosOffset */
-static void addPos(DocList *d, int iColumn, int iPos){
-  assert( d->nData>0 );
-  --d->nData;  /* remove previous terminator */
-  if( iColumn!=d->iLastColumn ){
-    assert( iColumn>d->iLastColumn );
-    appendVarint(d, POS_COLUMN);
-    appendVarint(d, iColumn);
-    d->iLastColumn = iColumn;
-    d->iLastPos = d->iLastOffset = 0;
-  }
-  assert( iPos>=d->iLastPos );
-  appendVarint(d, iPos-d->iLastPos+POS_BASE);
-  d->iLastPos = iPos;
-}
-
-/* Add a position to the last position list in a doclist. */
-static void docListAddPos(DocList *d, int iColumn, int iPos){
-  assert( d->iType==DL_POSITIONS );
-  addPos(d, iColumn, iPos);
-  appendVarint(d, POS_END);  /* add new terminator */
-}
-
-/*
-** Add a position and starting and ending offsets to a doclist.
-**
-** If the doclist is setup to handle only positions, then insert
-** the position only and ignore the offsets.
-*/
-static void docListAddPosOffset(
-  DocList *d,             /* Doclist under construction */
-  int iColumn,            /* Column the inserted term is part of */
-  int iPos,               /* Position of the inserted term */
-  int iStartOffset,       /* Starting offset of inserted term */
-  int iEndOffset          /* Ending offset of inserted term */
-){
-  assert( d->iType>=DL_POSITIONS );
-  addPos(d, iColumn, iPos);
-  if( d->iType==DL_POSITIONS_OFFSETS ){
-    assert( iStartOffset>=d->iLastOffset );
-    appendVarint(d, iStartOffset-d->iLastOffset);
-    d->iLastOffset = iStartOffset;
-    assert( iEndOffset>=iStartOffset );
-    appendVarint(d, iEndOffset-iStartOffset);
-  }
-  appendVarint(d, POS_END);  /* add new terminator */
-}
-
-/*
-** A DocListReader object is a cursor into a doclist.  Initialize
-** the cursor to the beginning of the doclist by calling readerInit().
-** Then use routines
-**
-**      peekDocid()
-**      readDocid()
-**      readPosition()
-**      skipPositionList()
-**      and so forth...
-**
-** to read information out of the doclist.  When we reach the end
-** of the doclist, atEnd() returns TRUE.
-*/
-typedef struct DocListReader {
-  DocList *pDoclist;  /* The document list we are stepping through */
-  char *p;            /* Pointer to next unread byte in the doclist */
-  int iLastColumn;
-  int iLastPos;  /* the last position read, or -1 when not in a position list */
-} DocListReader;
-
-/*
-** Initialize the DocListReader r to point to the beginning of pDoclist.
-*/
-static void readerInit(DocListReader *r, DocList *pDoclist){
-  r->pDoclist = pDoclist;
-  if( pDoclist!=NULL ){
-    r->p = pDoclist->pData;
-  }
-  r->iLastColumn = -1;
-  r->iLastPos = -1;
-}
-
-/*
-** Return TRUE if we have reached then end of pReader and there is
-** nothing else left to read.
-*/
-static int atEnd(DocListReader *pReader){
-  return pReader->pDoclist==0 || (pReader->p >= docListEnd(pReader->pDoclist));
-}
-
-/* Peek at the next docid without advancing the read pointer. 
-*/
-static sqlite_int64 peekDocid(DocListReader *pReader){
-  sqlite_int64 ret;
-  assert( !atEnd(pReader) );
-  assert( pReader->iLastPos==-1 );
-  getVarint(pReader->p, &ret);
-  return ret;
-}
-
-/* Read the next docid.   See also nextDocid().
-*/
-static sqlite_int64 readDocid(DocListReader *pReader){
-  sqlite_int64 ret;
-  assert( !atEnd(pReader) );
-  assert( pReader->iLastPos==-1 );
-  pReader->p += getVarint(pReader->p, &ret);
-  if( pReader->pDoclist->iType>=DL_POSITIONS ){
-    pReader->iLastColumn = 0;
-    pReader->iLastPos = 0;
-  }
-  return ret;
-}
-
-/* Read the next position and column index from a position list.
- * Returns the position, or -1 at the end of the list. */
-static int readPosition(DocListReader *pReader, int *iColumn){
-  int i;
-  int iType = pReader->pDoclist->iType;
-
-  if( pReader->iLastPos==-1 ){
-    return -1;
-  }
-  assert( !atEnd(pReader) );
-
-  if( iType<DL_POSITIONS ){
-    return -1;
-  }
-  pReader->p += getVarint32(pReader->p, &i);
-  if( i==POS_END ){
-    pReader->iLastColumn = pReader->iLastPos = -1;
-    *iColumn = -1;
-    return -1;
-  }
-  if( i==POS_COLUMN ){
-    pReader->p += getVarint32(pReader->p, &pReader->iLastColumn);
-    pReader->iLastPos = 0;
-    pReader->p += getVarint32(pReader->p, &i);
-    assert( i>=POS_BASE );
-  }
-  pReader->iLastPos += ((int) i)-POS_BASE;
-  if( iType>=DL_POSITIONS_OFFSETS ){
-    /* Skip over offsets, ignoring them for now. */
-    int iStart, iEnd;
-    pReader->p += getVarint32(pReader->p, &iStart);
-    pReader->p += getVarint32(pReader->p, &iEnd);
-  }
-  *iColumn = pReader->iLastColumn;
-  return pReader->iLastPos;
-}
-
-/* Skip past the end of a position list. */
-static void skipPositionList(DocListReader *pReader){
-  DocList *p = pReader->pDoclist;
-  if( p && p->iType>=DL_POSITIONS ){
-    int iColumn;
-    while( readPosition(pReader, &iColumn)!=-1 ){}
-  }
-}
-
-/* Skip over a docid, including its position list if the doclist has
- * positions. */
-static void skipDocument(DocListReader *pReader){
-  readDocid(pReader);
-  skipPositionList(pReader);
-}
-
-/* Skip past all docids which are less than [iDocid].  Returns 1 if a docid
- * matching [iDocid] was found.  */
-static int skipToDocid(DocListReader *pReader, sqlite_int64 iDocid){
-  sqlite_int64 d = 0;
-  while( !atEnd(pReader) && (d=peekDocid(pReader))<iDocid ){
-    skipDocument(pReader);
-  }
-  return !atEnd(pReader) && d==iDocid;
-}
-
-/* Return the first document in a document list.
-*/
-static sqlite_int64 firstDocid(DocList *d){
-  DocListReader r;
-  readerInit(&r, d);
-  return readDocid(&r);
-}
-
-#ifdef SQLITE_DEBUG
-/*
-** This routine is used for debugging purpose only.
-**
-** Write the content of a doclist to standard output.
-*/
-static void printDoclist(DocList *p){
-  DocListReader r;
-  const char *zSep = "";
-
-  readerInit(&r, p);
-  while( !atEnd(&r) ){
-    sqlite_int64 docid = readDocid(&r);
-    if( docid==0 ){
-      skipPositionList(&r);
-      continue;
-    }
-    printf("%s%lld", zSep, docid);
-    zSep =  ",";
-    if( p->iType>=DL_POSITIONS ){
-      int iPos, iCol;
-      const char *zDiv = "";
-      printf("(");
-      while( (iPos = readPosition(&r, &iCol))>=0 ){
-        printf("%s%d:%d", zDiv, iCol, iPos);
-        zDiv = ":";
-      }
-      printf(")");
-    }
-  }
-  printf("\n");
-  fflush(stdout);
-}
-#endif /* SQLITE_DEBUG */
-
-/* Trim the given doclist to contain only positions in column
- * [iRestrictColumn]. */
-static void docListRestrictColumn(DocList *in, int iRestrictColumn){
-  DocListReader r;
-  DocList out;
-
-  assert( in->iType>=DL_POSITIONS );
-  readerInit(&r, in);
-  docListInit(&out, DL_POSITIONS, NULL, 0);
-
-  while( !atEnd(&r) ){
-    sqlite_int64 iDocid = readDocid(&r);
-    int iPos, iColumn;
-
-    docListAddDocid(&out, iDocid);
-    while( (iPos = readPosition(&r, &iColumn)) != -1 ){
-      if( iColumn==iRestrictColumn ){
-        docListAddPos(&out, iColumn, iPos);
-      }
-    }
-  }
-
-  docListDestroy(in);
-  *in = out;
-}
-
-/* Trim the given doclist by discarding any docids without any remaining
- * positions. */
-static void docListDiscardEmpty(DocList *in) {
-  DocListReader r;
-  DocList out;
-
-  /* TODO: It would be nice to implement this operation in place; that
-   * could save a significant amount of memory in queries with long doclists. */
-  assert( in->iType>=DL_POSITIONS );
-  readerInit(&r, in);
-  docListInit(&out, DL_POSITIONS, NULL, 0);
-
-  while( !atEnd(&r) ){
-    sqlite_int64 iDocid = readDocid(&r);
-    int match = 0;
-    int iPos, iColumn;
-    while( (iPos = readPosition(&r, &iColumn)) != -1 ){
-      if( !match ){
-        docListAddDocid(&out, iDocid);
-        match = 1;
-      }
-      docListAddPos(&out, iColumn, iPos);
-    }
-  }
-
-  docListDestroy(in);
-  *in = out;
-}
-
-/* Helper function for docListUpdate() and docListAccumulate().
-** Splices a doclist element into the doclist represented by r,
-** leaving r pointing after the newly spliced element.
-*/
-static void docListSpliceElement(DocListReader *r, sqlite_int64 iDocid,
-                                 const char *pSource, int nSource){
-  DocList *d = r->pDoclist;
-  char *pTarget;
-  int nTarget, found;
-
-  found = skipToDocid(r, iDocid);
-
-  /* Describe slice in d to place pSource/nSource. */
-  pTarget = r->p;
-  if( found ){
-    skipDocument(r);
-    nTarget = r->p-pTarget;
-  }else{
-    nTarget = 0;
-  }
-
-  /* The sense of the following is that there are three possibilities.
-  ** If nTarget==nSource, we should not move any memory nor realloc.
-  ** If nTarget>nSource, trim target and realloc.
-  ** If nTarget<nSource, realloc then expand target.
-  */
-  if( nTarget>nSource ){
-    memmove(pTarget+nSource, pTarget+nTarget, docListEnd(d)-(pTarget+nTarget));
-  }
-  if( nTarget!=nSource ){
-    int iDoclist = pTarget-d->pData;
-    d->pData = realloc(d->pData, d->nData+nSource-nTarget);
-    pTarget = d->pData+iDoclist;
-  }
-  if( nTarget<nSource ){
-    memmove(pTarget+nSource, pTarget+nTarget, docListEnd(d)-(pTarget+nTarget));
-  }
-
-  memcpy(pTarget, pSource, nSource);
-  d->nData += nSource-nTarget;
-  r->p = pTarget+nSource;
-}
-
-/* Insert/update pUpdate into the doclist. */
-static void docListUpdate(DocList *d, DocList *pUpdate){
-  DocListReader reader;
-
-  assert( d!=NULL && pUpdate!=NULL );
-  assert( d->iType==pUpdate->iType);
-
-  readerInit(&reader, d);
-  docListSpliceElement(&reader, firstDocid(pUpdate),
-                       pUpdate->pData, pUpdate->nData);
-}
-
-/* Propagate elements from pUpdate to pAcc, overwriting elements with
-** matching docids.
-*/
-static void docListAccumulate(DocList *pAcc, DocList *pUpdate){
-  DocListReader accReader, updateReader;
-
-  /* Handle edge cases where one doclist is empty. */
-  assert( pAcc!=NULL );
-  if( pUpdate==NULL || pUpdate->nData==0 ) return;
-  if( pAcc->nData==0 ){
-    pAcc->pData = malloc(pUpdate->nData);
-    memcpy(pAcc->pData, pUpdate->pData, pUpdate->nData);
-    pAcc->nData = pUpdate->nData;
-    return;
-  }
-
-  readerInit(&accReader, pAcc);
-  readerInit(&updateReader, pUpdate);
-
-  while( !atEnd(&updateReader) ){
-    char *pSource = updateReader.p;
-    sqlite_int64 iDocid = readDocid(&updateReader);
-    skipPositionList(&updateReader);
-    docListSpliceElement(&accReader, iDocid, pSource, updateReader.p-pSource);
-  }
-}
-
-/*
-** Read the next docid off of pIn.  Return 0 if we reach the end.
-*
-* TODO: This assumes that docids are never 0, but they may actually be 0 since
-* users can choose docids when inserting into a full-text table.  Fix this.
-*/
-static sqlite_int64 nextDocid(DocListReader *pIn){
-  skipPositionList(pIn);
-  return atEnd(pIn) ? 0 : readDocid(pIn);
-}
-
-/*
-** pLeft and pRight are two DocListReaders that are pointing to
-** positions lists of the same document: iDocid. 
-**
-** If there are no instances in pLeft or pRight where the position
-** of pLeft is one less than the position of pRight, then this
-** routine adds nothing to pOut.
-**
-** If there are one or more instances where positions from pLeft
-** are exactly one less than positions from pRight, then add a new
-** document record to pOut.  If pOut wants to hold positions, then
-** include the positions from pRight that are one more than a
-** position in pLeft.  In other words:  pRight.iPos==pLeft.iPos+1.
-**
-** pLeft and pRight are left pointing at the next document record.
-*/
-static void mergePosList(
-  DocListReader *pLeft,    /* Left position list */
-  DocListReader *pRight,   /* Right position list */
-  sqlite_int64 iDocid,     /* The docid from pLeft and pRight */
-  DocList *pOut            /* Write the merged document record here */
-){
-  int iLeftCol, iLeftPos = readPosition(pLeft, &iLeftCol);
-  int iRightCol, iRightPos = readPosition(pRight, &iRightCol);
-  int match = 0;
-
-  /* Loop until we've reached the end of both position lists. */
-  while( iLeftPos!=-1 && iRightPos!=-1 ){
-    if( iLeftCol==iRightCol && iLeftPos+1==iRightPos ){
-      if( !match ){
-        docListAddDocid(pOut, iDocid);
-        match = 1;
-      }
-      if( pOut->iType>=DL_POSITIONS ){
-        docListAddPos(pOut, iRightCol, iRightPos);
-      }
-      iLeftPos = readPosition(pLeft, &iLeftCol);
-      iRightPos = readPosition(pRight, &iRightCol);
-    }else if( iRightCol<iLeftCol ||
-              (iRightCol==iLeftCol && iRightPos<iLeftPos+1) ){
-      iRightPos = readPosition(pRight, &iRightCol);
-    }else{
-      iLeftPos = readPosition(pLeft, &iLeftCol);
-    }
-  }
-  if( iLeftPos>=0 ) skipPositionList(pLeft);
-  if( iRightPos>=0 ) skipPositionList(pRight);
-}
-
-/* We have two doclists:  pLeft and pRight.
-** Write the phrase intersection of these two doclists into pOut.
-**
-** A phrase intersection means that two documents only match
-** if pLeft.iPos+1==pRight.iPos.
-**
-** The output pOut may or may not contain positions.  If pOut
-** does contain positions, they are the positions of pRight.
-*/
-static void docListPhraseMerge(
-  DocList *pLeft,    /* Doclist resulting from the words on the left */
-  DocList *pRight,   /* Doclist for the next word to the right */
-  DocList *pOut      /* Write the combined doclist here */
-){
-  DocListReader left, right;
-  sqlite_int64 docidLeft, docidRight;
-
-  readerInit(&left, pLeft);
-  readerInit(&right, pRight);
-  docidLeft = nextDocid(&left);
-  docidRight = nextDocid(&right);
-
-  while( docidLeft>0 && docidRight>0 ){
-    if( docidLeft<docidRight ){
-      docidLeft = nextDocid(&left);
-    }else if( docidRight<docidLeft ){
-      docidRight = nextDocid(&right);
-    }else{
-      mergePosList(&left, &right, docidLeft, pOut);
-      docidLeft = nextDocid(&left);
-      docidRight = nextDocid(&right);
-    }
-  }
-}
-
-/* We have two doclists:  pLeft and pRight.
-** Write the intersection of these two doclists into pOut.
-** Only docids are matched.  Position information is ignored.
-**
-** The output pOut never holds positions.
-*/
-static void docListAndMerge(
-  DocList *pLeft,    /* Doclist resulting from the words on the left */
-  DocList *pRight,   /* Doclist for the next word to the right */
-  DocList *pOut      /* Write the combined doclist here */
-){
-  DocListReader left, right;
-  sqlite_int64 docidLeft, docidRight;
-
-  assert( pOut->iType<DL_POSITIONS );
-
-  readerInit(&left, pLeft);
-  readerInit(&right, pRight);
-  docidLeft = nextDocid(&left);
-  docidRight = nextDocid(&right);
-
-  while( docidLeft>0 && docidRight>0 ){
-    if( docidLeft<docidRight ){
-      docidLeft = nextDocid(&left);
-    }else if( docidRight<docidLeft ){
-      docidRight = nextDocid(&right);
-    }else{
-      docListAddDocid(pOut, docidLeft);
-      docidLeft = nextDocid(&left);
-      docidRight = nextDocid(&right);
-    }
-  }
-}
-
-/* We have two doclists:  pLeft and pRight.
-** Write the union of these two doclists into pOut.
-** Only docids are matched.  Position information is ignored.
-**
-** The output pOut never holds positions.
-*/
-static void docListOrMerge(
-  DocList *pLeft,    /* Doclist resulting from the words on the left */
-  DocList *pRight,   /* Doclist for the next word to the right */
-  DocList *pOut      /* Write the combined doclist here */
-){
-  DocListReader left, right;
-  sqlite_int64 docidLeft, docidRight, priorLeft;
-
-  readerInit(&left, pLeft);
-  readerInit(&right, pRight);
-  docidLeft = nextDocid(&left);
-  docidRight = nextDocid(&right);
-
-  while( docidLeft>0 && docidRight>0 ){
-    if( docidLeft<=docidRight ){
-      docListAddDocid(pOut, docidLeft);
-    }else{
-      docListAddDocid(pOut, docidRight);
-    }
-    priorLeft = docidLeft;
-    if( docidLeft<=docidRight ){
-      docidLeft = nextDocid(&left);
-    }
-    if( docidRight>0 && docidRight<=priorLeft ){
-      docidRight = nextDocid(&right);
-    }
-  }
-  while( docidLeft>0 ){
-    docListAddDocid(pOut, docidLeft);
-    docidLeft = nextDocid(&left);
-  }
-  while( docidRight>0 ){
-    docListAddDocid(pOut, docidRight);
-    docidRight = nextDocid(&right);
-  }
-}
-
-/* We have two doclists:  pLeft and pRight.
-** Write into pOut all documents that occur in pLeft but not
-** in pRight.
-**
-** Only docids are matched.  Position information is ignored.
-**
-** The output pOut never holds positions.
-*/
-static void docListExceptMerge(
-  DocList *pLeft,    /* Doclist resulting from the words on the left */
-  DocList *pRight,   /* Doclist for the next word to the right */
-  DocList *pOut      /* Write the combined doclist here */
-){
-  DocListReader left, right;
-  sqlite_int64 docidLeft, docidRight, priorLeft;
-
-  readerInit(&left, pLeft);
-  readerInit(&right, pRight);
-  docidLeft = nextDocid(&left);
-  docidRight = nextDocid(&right);
-
-  while( docidLeft>0 && docidRight>0 ){
-    priorLeft = docidLeft;
-    if( docidLeft<docidRight ){
-      docListAddDocid(pOut, docidLeft);
-    }
-    if( docidLeft<=docidRight ){
-      docidLeft = nextDocid(&left);
-    }
-    if( docidRight>0 && docidRight<=priorLeft ){
-      docidRight = nextDocid(&right);
-    }
-  }
-  while( docidLeft>0 ){
-    docListAddDocid(pOut, docidLeft);
-    docidLeft = nextDocid(&left);
-  }
-}
-
-static char *string_dup_n(const char *s, int n){
-  char *str = malloc(n + 1);
-  memcpy(str, s, n);
-  str[n] = '\0';
-  return str;
-}
-
-/* Duplicate a string; the caller must free() the returned string.
- * (We don't use strdup() since it is not part of the standard C library and
- * may not be available everywhere.) */
-static char *string_dup(const char *s){
-  return string_dup_n(s, strlen(s));
-}
-
-/* Format a string, replacing each occurrence of the % character with
- * zDb.zName.  This may be more convenient than sqlite_mprintf()
- * when one string is used repeatedly in a format string.
- * The caller must free() the returned string. */
-static char *string_format(const char *zFormat,
-                           const char *zDb, const char *zName){
-  const char *p;
-  size_t len = 0;
-  size_t nDb = strlen(zDb);
-  size_t nName = strlen(zName);
-  size_t nFullTableName = nDb+1+nName;
-  char *result;
-  char *r;
-
-  /* first compute length needed */
-  for(p = zFormat ; *p ; ++p){
-    len += (*p=='%' ? nFullTableName : 1);
-  }
-  len += 1;  /* for null terminator */
-
-  r = result = malloc(len);
-  for(p = zFormat; *p; ++p){
-    if( *p=='%' ){
-      memcpy(r, zDb, nDb);
-      r += nDb;
-      *r++ = '.';
-      memcpy(r, zName, nName);
-      r += nName;
-    } else {
-      *r++ = *p;
-    }
-  }
-  *r++ = '\0';
-  assert( r == result + len );
-  return result;
-}
-
-static int sql_exec(sqlite3 *db, const char *zDb, const char *zName,
-                    const char *zFormat){
-  char *zCommand = string_format(zFormat, zDb, zName);
-  int rc;
-  TRACE(("FTS1 sql: %s\n", zCommand));
-  rc = sqlite3_exec(db, zCommand, NULL, 0, NULL);
-  free(zCommand);
-  return rc;
-}
-
-static int sql_prepare(sqlite3 *db, const char *zDb, const char *zName,
-                       sqlite3_stmt **ppStmt, const char *zFormat){
-  char *zCommand = string_format(zFormat, zDb, zName);
-  int rc;
-  TRACE(("FTS1 prepare: %s\n", zCommand));
-  rc = sqlite3_prepare(db, zCommand, -1, ppStmt, NULL);
-  free(zCommand);
-  return rc;
-}
-
-/* end utility functions */
-
-/* Forward reference */
-typedef struct fulltext_vtab fulltext_vtab;
-
-/* A single term in a query is represented by an instances of
-** the following structure.
-*/
-typedef struct QueryTerm {
-  short int nPhrase; /* How many following terms are part of the same phrase */
-  short int iPhrase; /* This is the i-th term of a phrase. */
-  short int iColumn; /* Column of the index that must match this term */
-  signed char isOr;  /* this term is preceded by "OR" */
-  signed char isNot; /* this term is preceded by "-" */
-  char *pTerm;       /* text of the term.  '\000' terminated.  malloced */
-  int nTerm;         /* Number of bytes in pTerm[] */
-} QueryTerm;
-
-
-/* A query string is parsed into a Query structure.
- *
- * We could, in theory, allow query strings to be complicated
- * nested expressions with precedence determined by parentheses.
- * But none of the major search engines do this.  (Perhaps the
- * feeling is that an parenthesized expression is two complex of
- * an idea for the average user to grasp.)  Taking our lead from
- * the major search engines, we will allow queries to be a list
- * of terms (with an implied AND operator) or phrases in double-quotes,
- * with a single optional "-" before each non-phrase term to designate
- * negation and an optional OR connector.
- *
- * OR binds more tightly than the implied AND, which is what the
- * major search engines seem to do.  So, for example:
- * 
- *    [one two OR three]     ==>    one AND (two OR three)
- *    [one OR two three]     ==>    (one OR two) AND three
- *
- * A "-" before a term matches all entries that lack that term.
- * The "-" must occur immediately before the term with in intervening
- * space.  This is how the search engines do it.
- *
- * A NOT term cannot be the right-hand operand of an OR.  If this
- * occurs in the query string, the NOT is ignored:
- *
- *    [one OR -two]          ==>    one OR two
- *
- */
-typedef struct Query {
-  fulltext_vtab *pFts;  /* The full text index */
-  int nTerms;           /* Number of terms in the query */
-  QueryTerm *pTerms;    /* Array of terms.  Space obtained from malloc() */
-  int nextIsOr;         /* Set the isOr flag on the next inserted term */
-  int nextColumn;       /* Next word parsed must be in this column */
-  int dfltColumn;       /* The default column */
-} Query;
-
-
-/*
-** An instance of the following structure keeps track of generated
-** matching-word offset information and snippets.
-*/
-typedef 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 iCol;      /* The column that contains the match */
-    short int iTerm;     /* The index in Query.pTerms[] of the matching term */
-    short int nByte;     /* Number of bytes in the term */
-    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) */
-} Snippet;
-
-
-typedef enum QueryType {
-  QUERY_GENERIC,   /* table scan */
-  QUERY_ROWID,     /* lookup by rowid */
-  QUERY_FULLTEXT   /* QUERY_FULLTEXT + [i] is a full-text search for column i*/
-} QueryType;
-
-/* TODO(shess) CHUNK_MAX controls how much data we allow in segment 0
-** before we start aggregating into larger segments.  Lower CHUNK_MAX
-** means that for a given input we have more individual segments per
-** term, which means more rows in the table and a bigger index (due to
-** both more rows and bigger rowids).  But it also reduces the average
-** cost of adding new elements to the segment 0 doclist, and it seems
-** to reduce the number of pages read and written during inserts.  256
-** was chosen by measuring insertion times for a certain input (first
-** 10k documents of Enron corpus), though including query performance
-** in the decision may argue for a larger value.
-*/
-#define CHUNK_MAX 256
-
-typedef enum fulltext_statement {
-  CONTENT_INSERT_STMT,
-  CONTENT_SELECT_STMT,
-  CONTENT_UPDATE_STMT,
-  CONTENT_DELETE_STMT,
-
-  TERM_SELECT_STMT,
-  TERM_SELECT_ALL_STMT,
-  TERM_INSERT_STMT,
-  TERM_UPDATE_STMT,
-  TERM_DELETE_STMT,
-
-  MAX_STMT                     /* Always at end! */
-} fulltext_statement;
-
-/* These must exactly match the enum above. */
-/* TODO(adam): Is there some risk that a statement (in particular,
-** pTermSelectStmt) will be used in two cursors at once, e.g.  if a
-** query joins a virtual table to itself?  If so perhaps we should
-** move some of these to the cursor object.
-*/
-static const char *const fulltext_zStatement[MAX_STMT] = {
-  /* CONTENT_INSERT */ NULL,  /* generated in contentInsertStatement() */
-  /* CONTENT_SELECT */ "select * from %_content where rowid = ?",
-  /* CONTENT_UPDATE */ NULL,  /* generated in contentUpdateStatement() */
-  /* CONTENT_DELETE */ "delete from %_content where rowid = ?",
-
-  /* TERM_SELECT */
-  "select rowid, doclist from %_term where term = ? and segment = ?",
-  /* TERM_SELECT_ALL */
-  "select doclist from %_term where term = ? order by segment",
-  /* TERM_INSERT */
-  "insert into %_term (rowid, term, segment, doclist) values (?, ?, ?, ?)",
-  /* TERM_UPDATE */ "update %_term set doclist = ? where rowid = ?",
-  /* TERM_DELETE */ "delete from %_term where rowid = ?",
-};
-
-/*
-** A connection to a fulltext index is an instance of the following
-** structure.  The xCreate and xConnect methods create an instance
-** of this structure and xDestroy and xDisconnect free that instance.
-** All other methods receive a pointer to the structure as one of their
-** arguments.
-*/
-struct fulltext_vtab {
-  sqlite3_vtab base;               /* Base class used by SQLite core */
-  sqlite3 *db;                     /* The database connection */
-  const char *zDb;                 /* logical database name */
-  const char *zName;               /* virtual table name */
-  int nColumn;                     /* number of columns in virtual table */
-  char **azColumn;                 /* column names.  malloced */
-  char **azContentColumn;          /* column names in content table; malloced */
-  sqlite3_tokenizer *pTokenizer;   /* tokenizer for inserts and queries */
-
-  /* Precompiled statements which we keep as long as the table is
-  ** open.
-  */
-  sqlite3_stmt *pFulltextStatements[MAX_STMT];
-};
-
-/*
-** When the core wants to do a query, it create a cursor using a
-** call to xOpen.  This structure is an instance of a cursor.  It
-** is destroyed by xClose.
-*/
-typedef struct fulltext_cursor {
-  sqlite3_vtab_cursor base;        /* Base class used by SQLite core */
-  QueryType iCursorType;           /* Copy of sqlite3_index_info.idxNum */
-  sqlite3_stmt *pStmt;             /* Prepared statement in use by the cursor */
-  int eof;                         /* True if at End Of Results */
-  Query q;                         /* Parsed query string */
-  Snippet snippet;                 /* Cached snippet for the current row */
-  int iColumn;                     /* Column being searched */
-  DocListReader result;  /* used when iCursorType == QUERY_FULLTEXT */ 
-} fulltext_cursor;
-
-static struct fulltext_vtab *cursor_vtab(fulltext_cursor *c){
-  return (fulltext_vtab *) c->base.pVtab;
-}
-
-static const sqlite3_module fulltextModule;   /* forward declaration */
-
-/* Append a list of strings separated by commas to a StringBuffer. */
-static void appendList(StringBuffer *sb, int nString, char **azString){
-  int i;
-  for(i=0; i<nString; ++i){
-    if( i>0 ) append(sb, ", ");
-    append(sb, azString[i]);
-  }
-}
-
-/* Return a dynamically generated statement of the form
- *   insert into %_content (rowid, ...) values (?, ...)
- */
-static const char *contentInsertStatement(fulltext_vtab *v){
-  StringBuffer sb;
-  int i;
-
-  initStringBuffer(&sb);
-  append(&sb, "insert into %_content (rowid, ");
-  appendList(&sb, v->nColumn, v->azContentColumn);
-  append(&sb, ") values (?");
-  for(i=0; i<v->nColumn; ++i)
-    append(&sb, ", ?");
-  append(&sb, ")");
-  return sb.s;
-}
-
-/* Return a dynamically generated statement of the form
- *   update %_content set [col_0] = ?, [col_1] = ?, ...
- *                    where rowid = ?
- */
-static const char *contentUpdateStatement(fulltext_vtab *v){
-  StringBuffer sb;
-  int i;
-
-  initStringBuffer(&sb);
-  append(&sb, "update %_content set ");
-  for(i=0; i<v->nColumn; ++i) {
-    if( i>0 ){
-      append(&sb, ", ");
-    }
-    append(&sb, v->azContentColumn[i]);
-    append(&sb, " = ?");
-  }
-  append(&sb, " where rowid = ?");
-  return sb.s;
-}
-
-/* Puts a freshly-prepared statement determined by iStmt in *ppStmt.
-** If the indicated statement has never been prepared, it is prepared
-** and cached, otherwise the cached version is reset.
-*/
-static int sql_get_statement(fulltext_vtab *v, fulltext_statement iStmt,
-                             sqlite3_stmt **ppStmt){
-  assert( iStmt<MAX_STMT );
-  if( v->pFulltextStatements[iStmt]==NULL ){
-    const char *zStmt;
-    int rc;
-    switch( iStmt ){
-      case CONTENT_INSERT_STMT:
-        zStmt = contentInsertStatement(v); break;
-      case CONTENT_UPDATE_STMT:
-        zStmt = contentUpdateStatement(v); break;
-      default:
-        zStmt = fulltext_zStatement[iStmt];
-    }
-    rc = sql_prepare(v->db, v->zDb, v->zName, &v->pFulltextStatements[iStmt],
-                         zStmt);
-    if( zStmt != fulltext_zStatement[iStmt]) free((void *) zStmt);
-    if( rc!=SQLITE_OK ) return rc;
-  } else {
-    int rc = sqlite3_reset(v->pFulltextStatements[iStmt]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  *ppStmt = v->pFulltextStatements[iStmt];
-  return SQLITE_OK;
-}
-
-/* Step the indicated statement, handling errors SQLITE_BUSY (by
-** retrying) and SQLITE_SCHEMA (by re-preparing and transferring
-** bindings to the new statement).
-** TODO(adam): We should extend this function so that it can work with
-** statements declared locally, not only globally cached statements.
-*/
-static int sql_step_statement(fulltext_vtab *v, fulltext_statement iStmt,
-                              sqlite3_stmt **ppStmt){
-  int rc;
-  sqlite3_stmt *s = *ppStmt;
-  assert( iStmt<MAX_STMT );
-  assert( s==v->pFulltextStatements[iStmt] );
-
-  while( (rc=sqlite3_step(s))!=SQLITE_DONE && rc!=SQLITE_ROW ){
-    if( rc==SQLITE_BUSY ) continue;
-    if( rc!=SQLITE_ERROR ) return rc;
-
-    /* If an SQLITE_SCHEMA error has occurred, then finalizing this
-     * statement is going to delete the fulltext_vtab structure. If
-     * the statement just executed is in the pFulltextStatements[]
-     * array, it will be finalized twice. So remove it before
-     * calling sqlite3_finalize().
-     */
-    v->pFulltextStatements[iStmt] = NULL;
-    rc = sqlite3_finalize(s);
-    break;
-  }
-  return rc;
-}
-
-/* Like sql_step_statement(), but convert SQLITE_DONE to SQLITE_OK.
-** Useful for statements like UPDATE, where we expect no results.
-*/
-static int sql_single_step_statement(fulltext_vtab *v,
-                                     fulltext_statement iStmt,
-                                     sqlite3_stmt **ppStmt){
-  int rc = sql_step_statement(v, iStmt, ppStmt);
-  return (rc==SQLITE_DONE) ? SQLITE_OK : rc;
-}
-
-/* insert into %_content (rowid, ...) values ([rowid], [pValues]) */
-static int content_insert(fulltext_vtab *v, sqlite3_value *rowid,
-                          sqlite3_value **pValues){
-  sqlite3_stmt *s;
-  int i;
-  int rc = sql_get_statement(v, CONTENT_INSERT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_value(s, 1, rowid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  for(i=0; i<v->nColumn; ++i){
-    rc = sqlite3_bind_value(s, 2+i, pValues[i]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  return sql_single_step_statement(v, CONTENT_INSERT_STMT, &s);
-}
-
-/* update %_content set col0 = pValues[0], col1 = pValues[1], ...
- *                  where rowid = [iRowid] */
-static int content_update(fulltext_vtab *v, sqlite3_value **pValues,
-                          sqlite_int64 iRowid){
-  sqlite3_stmt *s;
-  int i;
-  int rc = sql_get_statement(v, CONTENT_UPDATE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  for(i=0; i<v->nColumn; ++i){
-    rc = sqlite3_bind_value(s, 1+i, pValues[i]);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-
-  rc = sqlite3_bind_int64(s, 1+v->nColumn, iRowid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step_statement(v, CONTENT_UPDATE_STMT, &s);
-}
-
-static void freeStringArray(int nString, const char **pString){
-  int i;
-
-  for (i=0 ; i < nString ; ++i) {
-    if( pString[i]!=NULL ) free((void *) pString[i]);
-  }
-  free((void *) pString);
-}
-
-/* select * from %_content where rowid = [iRow]
- * The caller must delete the returned array and all strings in it.
- * null fields will be NULL in the returned array.
- *
- * TODO: Perhaps we should return pointer/length strings here for consistency
- * with other code which uses pointer/length. */
-static int content_select(fulltext_vtab *v, sqlite_int64 iRow,
-                          const char ***pValues){
-  sqlite3_stmt *s;
-  const char **values;
-  int i;
-  int rc;
-
-  *pValues = NULL;
-
-  rc = sql_get_statement(v, CONTENT_SELECT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sql_step_statement(v, CONTENT_SELECT_STMT, &s);
-  if( rc!=SQLITE_ROW ) return rc;
-
-  values = (const char **) malloc(v->nColumn * sizeof(const char *));
-  for(i=0; i<v->nColumn; ++i){
-    if( sqlite3_column_type(s, i)==SQLITE_NULL ){
-      values[i] = NULL;
-    }else{
-      values[i] = string_dup((char*)sqlite3_column_text(s, i));
-    }
-  }
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  if( rc==SQLITE_DONE ){
-    *pValues = values;
-    return SQLITE_OK;
-  }
-
-  freeStringArray(v->nColumn, values);
-  return rc;
-}
-
-/* delete from %_content where rowid = [iRow ] */
-static int content_delete(fulltext_vtab *v, sqlite_int64 iRow){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, CONTENT_DELETE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step_statement(v, CONTENT_DELETE_STMT, &s);
-}
-
-/* select rowid, doclist from %_term
- *  where term = [pTerm] and segment = [iSegment]
- * If found, returns SQLITE_ROW; the caller must free the
- * returned doclist.  If no rows found, returns SQLITE_DONE. */
-static int term_select(fulltext_vtab *v, const char *pTerm, int nTerm,
-                       int iSegment,
-                       sqlite_int64 *rowid, DocList *out){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, TERM_SELECT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_text(s, 1, pTerm, nTerm, SQLITE_STATIC);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 2, iSegment);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sql_step_statement(v, TERM_SELECT_STMT, &s);
-  if( rc!=SQLITE_ROW ) return rc;
-
-  *rowid = sqlite3_column_int64(s, 0);
-  docListInit(out, DL_DEFAULT,
-              sqlite3_column_blob(s, 1), sqlite3_column_bytes(s, 1));
-
-  /* We expect only one row.  We must execute another sqlite3_step()
-   * to complete the iteration; otherwise the table will remain locked. */
-  rc = sqlite3_step(s);
-  return rc==SQLITE_DONE ? SQLITE_ROW : rc;
-}
-
-/* Load the segment doclists for term pTerm and merge them in
-** appropriate order into out.  Returns SQLITE_OK if successful.  If
-** there are no segments for pTerm, successfully returns an empty
-** doclist in out.
-**
-** Each document consists of 1 or more "columns".  The number of
-** columns is v->nColumn.  If iColumn==v->nColumn, then return
-** position information about all columns.  If iColumn<v->nColumn,
-** then only return position information about the iColumn-th column
-** (where the first column is 0).
-*/
-static int term_select_all(
-  fulltext_vtab *v,     /* The fulltext index we are querying against */
-  int iColumn,          /* If <nColumn, only look at the iColumn-th column */
-  const char *pTerm,    /* The term whose posting lists we want */
-  int nTerm,            /* Number of bytes in pTerm */
-  DocList *out          /* Write the resulting doclist here */
-){
-  DocList doclist;
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, TERM_SELECT_ALL_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_text(s, 1, pTerm, nTerm, SQLITE_STATIC);
-  if( rc!=SQLITE_OK ) return rc;
-
-  docListInit(&doclist, DL_DEFAULT, 0, 0);
-
-  /* TODO(shess) Handle schema and busy errors. */
-  while( (rc=sql_step_statement(v, TERM_SELECT_ALL_STMT, &s))==SQLITE_ROW ){
-    DocList old;
-
-    /* TODO(shess) If we processed doclists from oldest to newest, we
-    ** could skip the malloc() involved with the following call.  For
-    ** now, I'd rather keep this logic similar to index_insert_term().
-    ** We could additionally drop elements when we see deletes, but
-    ** that would require a distinct version of docListAccumulate().
-    */
-    docListInit(&old, DL_DEFAULT,
-                sqlite3_column_blob(s, 0), sqlite3_column_bytes(s, 0));
-
-    if( iColumn<v->nColumn ){   /* querying a single column */
-      docListRestrictColumn(&old, iColumn);
-    }
-
-    /* doclist contains the newer data, so write it over old.  Then
-    ** steal accumulated result for doclist.
-    */
-    docListAccumulate(&old, &doclist);
-    docListDestroy(&doclist);
-    doclist = old;
-  }
-  if( rc!=SQLITE_DONE ){
-    docListDestroy(&doclist);
-    return rc;
-  }
-
-  docListDiscardEmpty(&doclist);
-  *out = doclist;
-  return SQLITE_OK;
-}
-
-/* insert into %_term (rowid, term, segment, doclist)
-               values ([piRowid], [pTerm], [iSegment], [doclist])
-** Lets sqlite select rowid if piRowid is NULL, else uses *piRowid.
-**
-** NOTE(shess) piRowid is IN, with values of "space of int64" plus
-** null, it is not used to pass data back to the caller.
-*/
-static int term_insert(fulltext_vtab *v, sqlite_int64 *piRowid,
-                       const char *pTerm, int nTerm,
-                       int iSegment, DocList *doclist){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, TERM_INSERT_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  if( piRowid==NULL ){
-    rc = sqlite3_bind_null(s, 1);
-  }else{
-    rc = sqlite3_bind_int64(s, 1, *piRowid);
-  }
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_text(s, 2, pTerm, nTerm, SQLITE_STATIC);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int(s, 3, iSegment);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_blob(s, 4, doclist->pData, doclist->nData, SQLITE_STATIC);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step_statement(v, TERM_INSERT_STMT, &s);
-}
-
-/* update %_term set doclist = [doclist] where rowid = [rowid] */
-static int term_update(fulltext_vtab *v, sqlite_int64 rowid,
-                       DocList *doclist){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, TERM_UPDATE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_blob(s, 1, doclist->pData, doclist->nData, SQLITE_STATIC);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 2, rowid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step_statement(v, TERM_UPDATE_STMT, &s);
-}
-
-static int term_delete(fulltext_vtab *v, sqlite_int64 rowid){
-  sqlite3_stmt *s;
-  int rc = sql_get_statement(v, TERM_DELETE_STMT, &s);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = sqlite3_bind_int64(s, 1, rowid);
-  if( rc!=SQLITE_OK ) return rc;
-
-  return sql_single_step_statement(v, TERM_DELETE_STMT, &s);
-}
-
-/*
-** Free the memory used to contain a fulltext_vtab structure.
-*/
-static void fulltext_vtab_destroy(fulltext_vtab *v){
-  int iStmt, i;
-
-  TRACE(("FTS1 Destroy %p\n", v));
-  for( iStmt=0; iStmt<MAX_STMT; iStmt++ ){
-    if( v->pFulltextStatements[iStmt]!=NULL ){
-      sqlite3_finalize(v->pFulltextStatements[iStmt]);
-      v->pFulltextStatements[iStmt] = NULL;
-    }
-  }
-
-  if( v->pTokenizer!=NULL ){
-    v->pTokenizer->pModule->xDestroy(v->pTokenizer);
-    v->pTokenizer = NULL;
-  }
-  
-  free(v->azColumn);
-  for(i = 0; i < v->nColumn; ++i) {
-    sqlite3_free(v->azContentColumn[i]);
-  }
-  free(v->azContentColumn);
-  free(v);
-}
-
-/*
-** Token types for parsing the arguments to xConnect or xCreate.
-*/
-#define TOKEN_EOF         0    /* End of file */
-#define TOKEN_SPACE       1    /* Any kind of whitespace */
-#define TOKEN_ID          2    /* An identifier */
-#define TOKEN_STRING      3    /* A string literal */
-#define TOKEN_PUNCT       4    /* A single punctuation character */
-
-/*
-** If X is a character that can be used in an identifier then
-** IdChar(X) will be true.  Otherwise it is false.
-**
-** For ASCII, any character with the high-order bit set is
-** allowed in an identifier.  For 7-bit characters, 
-** sqlite3IsIdChar[X] must be 1.
-**
-** Ticket #1066.  the SQL standard does not allow '$' in the
-** middle of identfiers.  But many SQL implementations do. 
-** SQLite will allow '$' in identifiers for compatibility.
-** But the feature is undocumented.
-*/
-static const char isIdChar[] = {
-/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
-    0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
-    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
-};
-#define IdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && isIdChar[c-0x20]))
-
-
-/*
-** Return the length of the token that begins at z[0]. 
-** Store the token type in *tokenType before returning.
-*/
-static int getToken(const char *z, int *tokenType){
-  int i, c;
-  switch( *z ){
-    case 0: {
-      *tokenType = TOKEN_EOF;
-      return 0;
-    }
-    case ' ': case '\t': case '\n': case '\f': case '\r': {
-      for(i=1; safe_isspace(z[i]); i++){}
-      *tokenType = TOKEN_SPACE;
-      return i;
-    }
-    case '`':
-    case '\'':
-    case '"': {
-      int delim = z[0];
-      for(i=1; (c=z[i])!=0; i++){
-        if( c==delim ){
-          if( z[i+1]==delim ){
-            i++;
-          }else{
-            break;
-          }
-        }
-      }
-      *tokenType = TOKEN_STRING;
-      return i + (c!=0);
-    }
-    case '[': {
-      for(i=1, c=z[0]; c!=']' && (c=z[i])!=0; i++){}
-      *tokenType = TOKEN_ID;
-      return i;
-    }
-    default: {
-      if( !IdChar(*z) ){
-        break;
-      }
-      for(i=1; IdChar(z[i]); i++){}
-      *tokenType = TOKEN_ID;
-      return i;
-    }
-  }
-  *tokenType = TOKEN_PUNCT;
-  return 1;
-}
-
-/*
-** A token extracted from a string is an instance of the following
-** structure.
-*/
-typedef struct Token {
-  const char *z;       /* Pointer to token text.  Not '\000' terminated */
-  short int n;         /* Length of the token text in bytes. */
-} Token;
-
-/*
-** Given a input string (which is really one of the argv[] parameters
-** passed into xConnect or xCreate) split the string up into tokens.
-** Return an array of pointers to '\000' terminated strings, one string
-** for each non-whitespace token.
-**
-** The returned array is terminated by a single NULL pointer.
-**
-** Space to hold the returned array is obtained from a single
-** malloc and should be freed by passing the return value to free().
-** The individual strings within the token list are all a part of
-** the single memory allocation and will all be freed at once.
-*/
-static char **tokenizeString(const char *z, int *pnToken){
-  int nToken = 0;
-  Token *aToken = malloc( strlen(z) * sizeof(aToken[0]) );
-  int n = 1;
-  int e, i;
-  int totalSize = 0;
-  char **azToken;
-  char *zCopy;
-  while( n>0 ){
-    n = getToken(z, &e);
-    if( e!=TOKEN_SPACE ){
-      aToken[nToken].z = z;
-      aToken[nToken].n = n;
-      nToken++;
-      totalSize += n+1;
-    }
-    z += n;
-  }
-  azToken = (char**)malloc( nToken*sizeof(char*) + totalSize );
-  zCopy = (char*)&azToken[nToken];
-  nToken--;
-  for(i=0; i<nToken; i++){
-    azToken[i] = zCopy;
-    n = aToken[i].n;
-    memcpy(zCopy, aToken[i].z, n);
-    zCopy[n] = 0;
-    zCopy += n+1;
-  }
-  azToken[nToken] = 0;
-  free(aToken);
-  *pnToken = nToken;
-  return azToken;
-}
-
-/*
-** Convert an SQL-style quoted string into a normal string by removing
-** the quote characters.  The conversion is done in-place.  If the
-** input does not begin with a quote character, then this routine
-** is a no-op.
-**
-** Examples:
-**
-**     "abc"   becomes   abc
-**     'xyz'   becomes   xyz
-**     [pqr]   becomes   pqr
-**     `mno`   becomes   mno
-*/
-static void dequoteString(char *z){
-  int quote;
-  int i, j;
-  if( z==0 ) return;
-  quote = z[0];
-  switch( quote ){
-    case '\'':  break;
-    case '"':   break;
-    case '`':   break;                /* For MySQL compatibility */
-    case '[':   quote = ']';  break;  /* For MS SqlServer compatibility */
-    default:    return;
-  }
-  for(i=1, j=0; z[i]; i++){
-    if( z[i]==quote ){
-      if( z[i+1]==quote ){
-        z[j++] = quote;
-        i++;
-      }else{
-        z[j++] = 0;
-        break;
-      }
-    }else{
-      z[j++] = z[i];
-    }
-  }
-}
-
-/*
-** The input azIn is a NULL-terminated list of tokens.  Remove the first
-** token and all punctuation tokens.  Remove the quotes from
-** around string literal tokens.
-**
-** Example:
-**
-**     input:      tokenize chinese ( 'simplifed' , 'mixed' )
-**     output:     chinese simplifed mixed
-**
-** Another example:
-**
-**     input:      delimiters ( '[' , ']' , '...' )
-**     output:     [ ] ...
-*/
-static void tokenListToIdList(char **azIn){
-  int i, j;
-  if( azIn ){
-    for(i=0, j=-1; azIn[i]; i++){
-      if( safe_isalnum(azIn[i][0]) || azIn[i][1] ){
-        dequoteString(azIn[i]);
-        if( j>=0 ){
-          azIn[j] = azIn[i];
-        }
-        j++;
-      }
-    }
-    azIn[j] = 0;
-  }
-}
-
-
-/*
-** Find the first alphanumeric token in the string zIn.  Null-terminate
-** this token.  Remove any quotation marks.  And return a pointer to
-** the result.
-*/
-static char *firstToken(char *zIn, char **pzTail){
-  int n, ttype;
-  while(1){
-    n = getToken(zIn, &ttype);
-    if( ttype==TOKEN_SPACE ){
-      zIn += n;
-    }else if( ttype==TOKEN_EOF ){
-      *pzTail = zIn;
-      return 0;
-    }else{
-      zIn[n] = 0;
-      *pzTail = &zIn[1];
-      dequoteString(zIn);
-      return zIn;
-    }
-  }
-  /*NOTREACHED*/
-}
-
-/* Return true if...
-**
-**   *  s begins with the string t, ignoring case
-**   *  s is longer than t
-**   *  The first character of s beyond t is not a alphanumeric
-** 
-** Ignore leading space in *s.
-**
-** To put it another way, return true if the first token of
-** s[] is t[].
-*/
-static int startsWith(const char *s, const char *t){
-  while( safe_isspace(*s) ){ s++; }
-  while( *t ){
-    if( safe_tolower(*s++)!=safe_tolower(*t++) ) return 0;
-  }
-  return *s!='_' && !safe_isalnum(*s);
-}
-
-/*
-** An instance of this structure defines the "spec" of a
-** full text index.  This structure is populated by parseSpec
-** and use by fulltextConnect and fulltextCreate.
-*/
-typedef struct TableSpec {
-  const char *zDb;         /* Logical database name */
-  const char *zName;       /* Name of the full-text index */
-  int nColumn;             /* Number of columns to be indexed */
-  char **azColumn;         /* Original names of columns to be indexed */
-  char **azContentColumn;  /* Column names for %_content */
-  char **azTokenizer;      /* Name of tokenizer and its arguments */
-} TableSpec;
-
-/*
-** Reclaim all of the memory used by a TableSpec
-*/
-static void clearTableSpec(TableSpec *p) {
-  free(p->azColumn);
-  free(p->azContentColumn);
-  free(p->azTokenizer);
-}
-
-/* Parse a CREATE VIRTUAL TABLE statement, which looks like this:
- *
- * CREATE VIRTUAL TABLE email
- *        USING fts1(subject, body, tokenize mytokenizer(myarg))
- *
- * We return parsed information in a TableSpec structure.
- * 
- */
-static int parseSpec(TableSpec *pSpec, int argc, const char *const*argv,
-                     char**pzErr){
-  int i, n;
-  char *z, *zDummy;
-  char **azArg;
-  const char *zTokenizer = 0;    /* argv[] entry describing the tokenizer */
-
-  assert( argc>=3 );
-  /* Current interface:
-  ** argv[0] - module name
-  ** argv[1] - database name
-  ** argv[2] - table name
-  ** argv[3..] - columns, optionally followed by tokenizer specification
-  **             and snippet delimiters specification.
-  */
-
-  /* Make a copy of the complete argv[][] array in a single allocation.
-  ** The argv[][] array is read-only and transient.  We can write to the
-  ** copy in order to modify things and the copy is persistent.
-  */
-  memset(pSpec, 0, sizeof(*pSpec));
-  for(i=n=0; i<argc; i++){
-    n += strlen(argv[i]) + 1;
-  }
-  azArg = malloc( sizeof(char*)*argc + n );
-  if( azArg==0 ){
-    return SQLITE_NOMEM;
-  }
-  z = (char*)&azArg[argc];
-  for(i=0; i<argc; i++){
-    azArg[i] = z;
-    strcpy(z, argv[i]);
-    z += strlen(z)+1;
-  }
-
-  /* Identify the column names and the tokenizer and delimiter arguments
-  ** in the argv[][] array.
-  */
-  pSpec->zDb = azArg[1];
-  pSpec->zName = azArg[2];
-  pSpec->nColumn = 0;
-  pSpec->azColumn = azArg;
-  zTokenizer = "tokenize simple";
-  for(i=3; i<argc; ++i){
-    if( startsWith(azArg[i],"tokenize") ){
-      zTokenizer = azArg[i];
-    }else{
-      z = azArg[pSpec->nColumn] = firstToken(azArg[i], &zDummy);
-      pSpec->nColumn++;
-    }
-  }
-  if( pSpec->nColumn==0 ){
-    azArg[0] = "content";
-    pSpec->nColumn = 1;
-  }
-
-  /*
-  ** Construct the list of content column names.
-  **
-  ** Each content column name will be of the form cNNAAAA
-  ** where NN is the column number and AAAA is the sanitized
-  ** column name.  "sanitized" means that special characters are
-  ** converted to "_".  The cNN prefix guarantees that all column
-  ** names are unique.
-  **
-  ** The AAAA suffix is not strictly necessary.  It is included
-  ** for the convenience of people who might examine the generated
-  ** %_content table and wonder what the columns are used for.
-  */
-  pSpec->azContentColumn = malloc( pSpec->nColumn * sizeof(char *) );
-  if( pSpec->azContentColumn==0 ){
-    clearTableSpec(pSpec);
-    return SQLITE_NOMEM;
-  }
-  for(i=0; i<pSpec->nColumn; i++){
-    char *p;
-    pSpec->azContentColumn[i] = sqlite3_mprintf("c%d%s", i, azArg[i]);
-    for (p = pSpec->azContentColumn[i]; *p ; ++p) {
-      if( !safe_isalnum(*p) ) *p = '_';
-    }
-  }
-
-  /*
-  ** Parse the tokenizer specification string.
-  */
-  pSpec->azTokenizer = tokenizeString(zTokenizer, &n);
-  tokenListToIdList(pSpec->azTokenizer);
-
-  return SQLITE_OK;
-}
-
-/*
-** Generate a CREATE TABLE statement that describes the schema of
-** the virtual table.  Return a pointer to this schema string.
-**
-** Space is obtained from sqlite3_mprintf() and should be freed
-** using sqlite3_free().
-*/
-static char *fulltextSchema(
-  int nColumn,                  /* Number of columns */
-  const char *const* azColumn,  /* List of columns */
-  const char *zTableName        /* Name of the table */
-){
-  int i;
-  char *zSchema, *zNext;
-  const char *zSep = "(";
-  zSchema = sqlite3_mprintf("CREATE TABLE x");
-  for(i=0; i<nColumn; i++){
-    zNext = sqlite3_mprintf("%s%s%Q", zSchema, zSep, azColumn[i]);
-    sqlite3_free(zSchema);
-    zSchema = zNext;
-    zSep = ",";
-  }
-  zNext = sqlite3_mprintf("%s,%Q)", zSchema, zTableName);
-  sqlite3_free(zSchema);
-  return zNext;
-}
-
-/*
-** Build a new sqlite3_vtab structure that will describe the
-** fulltext index defined by spec.
-*/
-static int constructVtab(
-  sqlite3 *db,              /* The SQLite database connection */
-  TableSpec *spec,          /* Parsed spec information from parseSpec() */
-  sqlite3_vtab **ppVTab,    /* Write the resulting vtab structure here */
-  char **pzErr              /* Write any error message here */
-){
-  int rc;
-  int n;
-  fulltext_vtab *v = 0;
-  const sqlite3_tokenizer_module *m = NULL;
-  char *schema;
-
-  v = (fulltext_vtab *) malloc(sizeof(fulltext_vtab));
-  if( v==0 ) return SQLITE_NOMEM;
-  memset(v, 0, sizeof(*v));
-  /* sqlite will initialize v->base */
-  v->db = db;
-  v->zDb = spec->zDb;       /* Freed when azColumn is freed */
-  v->zName = spec->zName;   /* Freed when azColumn is freed */
-  v->nColumn = spec->nColumn;
-  v->azContentColumn = spec->azContentColumn;
-  spec->azContentColumn = 0;
-  v->azColumn = spec->azColumn;
-  spec->azColumn = 0;
-
-  if( spec->azTokenizer==0 ){
-    return SQLITE_NOMEM;
-  }
-  /* TODO(shess) For now, add new tokenizers as else if clauses. */
-  if( spec->azTokenizer[0]==0 || startsWith(spec->azTokenizer[0], "simple") ){
-    sqlite3Fts1SimpleTokenizerModule(&m);
-  }else if( startsWith(spec->azTokenizer[0], "porter") ){
-    sqlite3Fts1PorterTokenizerModule(&m);
-  }else{
-    *pzErr = sqlite3_mprintf("unknown tokenizer: %s", spec->azTokenizer[0]);
-    rc = SQLITE_ERROR;
-    goto err;
-  }
-  for(n=0; spec->azTokenizer[n]; n++){}
-  if( n ){
-    rc = m->xCreate(n-1, (const char*const*)&spec->azTokenizer[1],
-                    &v->pTokenizer);
-  }else{
-    rc = m->xCreate(0, 0, &v->pTokenizer);
-  }
-  if( rc!=SQLITE_OK ) goto err;
-  v->pTokenizer->pModule = m;
-
-  /* TODO: verify the existence of backing tables foo_content, foo_term */
-
-  schema = fulltextSchema(v->nColumn, (const char*const*)v->azColumn,
-                          spec->zName);
-  rc = sqlite3_declare_vtab(db, schema);
-  sqlite3_free(schema);
-  if( rc!=SQLITE_OK ) goto err;
-
-  memset(v->pFulltextStatements, 0, sizeof(v->pFulltextStatements));
-
-  *ppVTab = &v->base;
-  TRACE(("FTS1 Connect %p\n", v));
-
-  return rc;
-
-err:
-  fulltext_vtab_destroy(v);
-  return rc;
-}
-
-static int fulltextConnect(
-  sqlite3 *db,
-  void *pAux,
-  int argc, const char *const*argv,
-  sqlite3_vtab **ppVTab,
-  char **pzErr
-){
-  TableSpec spec;
-  int rc = parseSpec(&spec, argc, argv, pzErr);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = constructVtab(db, &spec, ppVTab, pzErr);
-  clearTableSpec(&spec);
-  return rc;
-}
-
-  /* The %_content table holds the text of each document, with
-  ** the rowid used as the docid.
-  **
-  ** The %_term table maps each term to a document list blob
-  ** containing elements sorted by ascending docid, each element
-  ** encoded as:
-  **
-  **   docid varint-encoded
-  **   token elements:
-  **     position+1 varint-encoded as delta from previous position
-  **     start offset varint-encoded as delta from previous start offset
-  **     end offset varint-encoded as delta from start offset
-  **
-  ** The sentinel position of 0 indicates the end of the token list.
-  **
-  ** Additionally, doclist blobs are chunked into multiple segments,
-  ** using segment to order the segments.  New elements are added to
-  ** the segment at segment 0, until it exceeds CHUNK_MAX.  Then
-  ** segment 0 is deleted, and the doclist is inserted at segment 1.
-  ** If there is already a doclist at segment 1, the segment 0 doclist
-  ** is merged with it, the segment 1 doclist is deleted, and the
-  ** merged doclist is inserted at segment 2, repeating those
-  ** operations until an insert succeeds.
-  **
-  ** Since this structure doesn't allow us to update elements in place
-  ** in case of deletion or update, these are simply written to
-  ** segment 0 (with an empty token list in case of deletion), with
-  ** docListAccumulate() taking care to retain lower-segment
-  ** information in preference to higher-segment information.
-  */
-  /* TODO(shess) Provide a VACUUM type operation which both removes
-  ** deleted elements which are no longer necessary, and duplicated
-  ** elements.  I suspect this will probably not be necessary in
-  ** practice, though.
-  */
-static int fulltextCreate(sqlite3 *db, void *pAux,
-                          int argc, const char * const *argv,
-                          sqlite3_vtab **ppVTab, char **pzErr){
-  int rc;
-  TableSpec spec;
-  StringBuffer schema;
-  TRACE(("FTS1 Create\n"));
-
-  rc = parseSpec(&spec, argc, argv, pzErr);
-  if( rc!=SQLITE_OK ) return rc;
-
-  initStringBuffer(&schema);
-  append(&schema, "CREATE TABLE %_content(");
-  appendList(&schema, spec.nColumn, spec.azContentColumn);
-  append(&schema, ")");
-  rc = sql_exec(db, spec.zDb, spec.zName, schema.s);
-  free(schema.s);
-  if( rc!=SQLITE_OK ) goto out;
-
-  rc = sql_exec(db, spec.zDb, spec.zName,
-    "create table %_term(term text, segment integer, doclist blob, "
-                        "primary key(term, segment));");
-  if( rc!=SQLITE_OK ) goto out;
-
-  rc = constructVtab(db, &spec, ppVTab, pzErr);
-
-out:
-  clearTableSpec(&spec);
-  return rc;
-}
-
-/* Decide how to handle an SQL query. */
-static int fulltextBestIndex(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
-  int i;
-  TRACE(("FTS1 BestIndex\n"));
-
-  for(i=0; i<pInfo->nConstraint; ++i){
-    const struct sqlite3_index_constraint *pConstraint;
-    pConstraint = &pInfo->aConstraint[i];
-    if( pConstraint->usable ) {
-      if( pConstraint->iColumn==-1 &&
-          pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ ){
-        pInfo->idxNum = QUERY_ROWID;      /* lookup by rowid */
-        TRACE(("FTS1 QUERY_ROWID\n"));
-      } else if( pConstraint->iColumn>=0 &&
-                 pConstraint->op==SQLITE_INDEX_CONSTRAINT_MATCH ){
-        /* full-text search */
-        pInfo->idxNum = QUERY_FULLTEXT + pConstraint->iColumn;
-        TRACE(("FTS1 QUERY_FULLTEXT %d\n", pConstraint->iColumn));
-      } else continue;
-
-      pInfo->aConstraintUsage[i].argvIndex = 1;
-      pInfo->aConstraintUsage[i].omit = 1;
-
-      /* An arbitrary value for now.
-       * TODO: Perhaps rowid matches should be considered cheaper than
-       * full-text searches. */
-      pInfo->estimatedCost = 1.0;   
-
-      return SQLITE_OK;
-    }
-  }
-  pInfo->idxNum = QUERY_GENERIC;
-  return SQLITE_OK;
-}
-
-static int fulltextDisconnect(sqlite3_vtab *pVTab){
-  TRACE(("FTS1 Disconnect %p\n", pVTab));
-  fulltext_vtab_destroy((fulltext_vtab *)pVTab);
-  return SQLITE_OK;
-}
-
-static int fulltextDestroy(sqlite3_vtab *pVTab){
-  fulltext_vtab *v = (fulltext_vtab *)pVTab;
-  int rc;
-
-  TRACE(("FTS1 Destroy %p\n", pVTab));
-  rc = sql_exec(v->db, v->zDb, v->zName,
-                "drop table if exists %_content;"
-                "drop table if exists %_term;"
-                );
-  if( rc!=SQLITE_OK ) return rc;
-
-  fulltext_vtab_destroy((fulltext_vtab *)pVTab);
-  return SQLITE_OK;
-}
-
-static int fulltextOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
-  fulltext_cursor *c;
-
-  c = (fulltext_cursor *) calloc(sizeof(fulltext_cursor), 1);
-  /* sqlite will initialize c->base */
-  *ppCursor = &c->base;
-  TRACE(("FTS1 Open %p: %p\n", pVTab, c));
-
-  return SQLITE_OK;
-}
-
-
-/* Free all of the dynamically allocated memory held by *q
-*/
-static void queryClear(Query *q){
-  int i;
-  for(i = 0; i < q->nTerms; ++i){
-    free(q->pTerms[i].pTerm);
-  }
-  free(q->pTerms);
-  memset(q, 0, sizeof(*q));
-}
-
-/* Free all of the dynamically allocated memory held by the
-** Snippet
-*/
-static void snippetClear(Snippet *p){
-  free(p->aMatch);
-  free(p->zOffset);
-  free(p->zSnippet);
-  memset(p, 0, sizeof(*p));
-}
-/*
-** Append a single entry to the p->aMatch[] log.
-*/
-static void snippetAppendMatch(
-  Snippet *p,               /* Append the entry to this snippet */
-  int iCol, int iTerm,      /* The column and query term */
-  int iStart, int nByte     /* Offset and size of the match */
-){
-  int i;
-  struct snippetMatch *pMatch;
-  if( p->nMatch+1>=p->nAlloc ){
-    p->nAlloc = p->nAlloc*2 + 10;
-    p->aMatch = realloc(p->aMatch, p->nAlloc*sizeof(p->aMatch[0]) );
-    if( p->aMatch==0 ){
-      p->nMatch = 0;
-      p->nAlloc = 0;
-      return;
-    }
-  }
-  i = p->nMatch++;
-  pMatch = &p->aMatch[i];
-  pMatch->iCol = iCol;
-  pMatch->iTerm = iTerm;
-  pMatch->iStart = iStart;
-  pMatch->nByte = nByte;
-}
-
-/*
-** Sizing information for the circular buffer used in snippetOffsetsOfColumn()
-*/
-#define FTS1_ROTOR_SZ   (32)
-#define FTS1_ROTOR_MASK (FTS1_ROTOR_SZ-1)
-
-/*
-** Add entries to pSnippet->aMatch[] for every match that occurs against
-** document zDoc[0..nDoc-1] which is stored in column iColumn.
-*/
-static void snippetOffsetsOfColumn(
-  Query *pQuery,
-  Snippet *pSnippet,
-  int iColumn,
-  const char *zDoc,
-  int nDoc
-){
-  const sqlite3_tokenizer_module *pTModule;  /* The tokenizer module */
-  sqlite3_tokenizer *pTokenizer;             /* The specific tokenizer */
-  sqlite3_tokenizer_cursor *pTCursor;        /* Tokenizer cursor */
-  fulltext_vtab *pVtab;                /* The full text index */
-  int nColumn;                         /* Number of columns in the index */
-  const QueryTerm *aTerm;              /* Query string terms */
-  int nTerm;                           /* Number of query string terms */  
-  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[FTS1_ROTOR_SZ];      /* Beginning offset of token */
-  int iRotorLen[FTS1_ROTOR_SZ];        /* Length of token */
-
-  pVtab = pQuery->pFts;
-  nColumn = pVtab->nColumn;
-  pTokenizer = pVtab->pTokenizer;
-  pTModule = pTokenizer->pModule;
-  rc = pTModule->xOpen(pTokenizer, zDoc, nDoc, &pTCursor);
-  if( rc ) return;
-  pTCursor->pTokenizer = pTokenizer;
-  aTerm = pQuery->pTerms;
-  nTerm = pQuery->nTerms;
-  if( nTerm>=FTS1_ROTOR_SZ ){
-    nTerm = FTS1_ROTOR_SZ - 1;
-  }
-  prevMatch = 0;
-  while(1){
-    rc = pTModule->xNext(pTCursor, &zToken, &nToken, &iBegin, &iEnd, &iPos);
-    if( rc ) break;
-    iRotorBegin[iRotor&FTS1_ROTOR_MASK] = iBegin;
-    iRotorLen[iRotor&FTS1_ROTOR_MASK] = iEnd-iBegin;
-    match = 0;
-    for(i=0; i<nTerm; i++){
-      int iCol;
-      iCol = aTerm[i].iColumn;
-      if( iCol>=0 && iCol<nColumn && iCol!=iColumn ) continue;
-      if( aTerm[i].nTerm!=nToken ) continue;
-      if( memcmp(aTerm[i].pTerm, zToken, nToken) ) continue;
-      if( aTerm[i].iPhrase>1 && (prevMatch & (1<<i))==0 ) continue;
-      match |= 1<<i;
-      if( i==nTerm-1 || aTerm[i+1].iPhrase==1 ){
-        for(j=aTerm[i].iPhrase-1; j>=0; j--){
-          int k = (iRotor-j) & FTS1_ROTOR_MASK;
-          snippetAppendMatch(pSnippet, iColumn, i-j,
-                iRotorBegin[k], iRotorLen[k]);
-        }
-      }
-    }
-    prevMatch = match<<1;
-    iRotor++;
-  }
-  pTModule->xClose(pTCursor);  
-}
-
-
-/*
-** Compute all offsets for the current row of the query.  
-** If the offsets have already been computed, this routine is a no-op.
-*/
-static void snippetAllOffsets(fulltext_cursor *p){
-  int nColumn;
-  int iColumn, i;
-  int iFirst, iLast;
-  fulltext_vtab *pFts;
-
-  if( p->snippet.nMatch ) return;
-  if( p->q.nTerms==0 ) return;
-  pFts = p->q.pFts;
-  nColumn = pFts->nColumn;
-  iColumn = p->iCursorType - QUERY_FULLTEXT;
-  if( iColumn<0 || iColumn>=nColumn ){
-    iFirst = 0;
-    iLast = nColumn-1;
-  }else{
-    iFirst = iColumn;
-    iLast = iColumn;
-  }
-  for(i=iFirst; i<=iLast; i++){
-    const char *zDoc;
-    int nDoc;
-    zDoc = (const char*)sqlite3_column_text(p->pStmt, i+1);
-    nDoc = sqlite3_column_bytes(p->pStmt, i+1);
-    snippetOffsetsOfColumn(&p->q, &p->snippet, i, zDoc, nDoc);
-  }
-}
-
-/*
-** Convert the information in the aMatch[] array of the snippet
-** into the string zOffset[0..nOffset-1].
-*/
-static void snippetOffsetText(Snippet *p){
-  int i;
-  int cnt = 0;
-  StringBuffer sb;
-  char zBuf[200];
-  if( p->zOffset ) return;
-  initStringBuffer(&sb);
-  for(i=0; i<p->nMatch; i++){
-    struct snippetMatch *pMatch = &p->aMatch[i];
-    zBuf[0] = ' ';
-    sqlite3_snprintf(sizeof(zBuf)-1, &zBuf[cnt>0], "%d %d %d %d",
-        pMatch->iCol, pMatch->iTerm, pMatch->iStart, pMatch->nByte);
-    append(&sb, zBuf);
-    cnt++;
-  }
-  p->zOffset = sb.s;
-  p->nOffset = sb.len;
-}
-
-/*
-** 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; 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( safe_isspace(zDoc[iBreak-i]) ){
-      return iBreak - i + 1;
-    }
-    if( safe_isspace(zDoc[iBreak+i]) ){
-      return iBreak + i + 1;
-    }
-  }
-  return iBreak;
-}
-
-/*
-** If the StringBuffer does not end in white space, add a single
-** space character to the end.
-*/
-static void appendWhiteSpace(StringBuffer *p){
-  if( p->len==0 ) return;
-  if( safe_isspace(p->s[p->len-1]) ) return;
-  append(p, " ");
-}
-
-/*
-** Remove white space from teh end of the StringBuffer
-*/
-static void trimWhiteSpace(StringBuffer *p){
-  while( p->len>0 && safe_isspace(p->s[p->len-1]) ){
-    p->len--;
-  }
-}
-
-
-
-/*
-** 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(
-  fulltext_cursor *pCursor,   /* The cursor we need the snippet for */
-  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;
-  
-
-  free(pCursor->snippet.zSnippet);
-  pCursor->snippet.zSnippet = 0;
-  aMatch = pCursor->snippet.aMatch;
-  nMatch = pCursor->snippet.nMatch;
-  initStringBuffer(&sb);
-
-  for(i=0; i<nMatch; i++){
-    aMatch[i].snStatus = SNIPPET_IGNORE;
-  }
-  nDesired = 0;
-  for(i=0; i<pCursor->q.nTerms; 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 ){
-      trimWhiteSpace(&sb);
-      appendWhiteSpace(&sb);
-      append(&sb, zEllipsis);
-      appendWhiteSpace(&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 ){
-        nappend(&sb, &zDoc[iStart], aMatch[iMatch].iStart - iStart);
-        iStart = aMatch[iMatch].iStart;
-        append(&sb, zStartMark);
-        nappend(&sb, &zDoc[iStart], aMatch[iMatch].nByte);
-        append(&sb, zEndMark);
-        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{
-        nappend(&sb, &zDoc[iStart], iEnd - iStart);
-        iStart = iEnd;
-      }
-    }
-    tailCol = iCol;
-    tailOffset = iEnd;
-  }
-  trimWhiteSpace(&sb);
-  if( tailEllipsis ){
-    appendWhiteSpace(&sb);
-    append(&sb, zEllipsis);
-  }
-  pCursor->snippet.zSnippet = sb.s;
-  pCursor->snippet.nSnippet = sb.len;  
-}
-
-
-/*
-** Close the cursor.  For additional information see the documentation
-** on the xClose method of the virtual table interface.
-*/
-static int fulltextClose(sqlite3_vtab_cursor *pCursor){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  TRACE(("FTS1 Close %p\n", c));
-  sqlite3_finalize(c->pStmt);
-  queryClear(&c->q);
-  snippetClear(&c->snippet);
-  if( c->result.pDoclist!=NULL ){
-    docListDelete(c->result.pDoclist);
-  }
-  free(c);
-  return SQLITE_OK;
-}
-
-static int fulltextNext(sqlite3_vtab_cursor *pCursor){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  sqlite_int64 iDocid;
-  int rc;
-
-  TRACE(("FTS1 Next %p\n", pCursor));
-  snippetClear(&c->snippet);
-  if( c->iCursorType < QUERY_FULLTEXT ){
-    /* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
-    rc = sqlite3_step(c->pStmt);
-    switch( rc ){
-      case SQLITE_ROW:
-        c->eof = 0;
-        return SQLITE_OK;
-      case SQLITE_DONE:
-        c->eof = 1;
-        return SQLITE_OK;
-      default:
-        c->eof = 1;
-        return rc;
-    }
-  } else {  /* full-text query */
-    rc = sqlite3_reset(c->pStmt);
-    if( rc!=SQLITE_OK ) return rc;
-
-    iDocid = nextDocid(&c->result);
-    if( iDocid==0 ){
-      c->eof = 1;
-      return SQLITE_OK;
-    }
-    rc = sqlite3_bind_int64(c->pStmt, 1, iDocid);
-    if( rc!=SQLITE_OK ) return rc;
-    /* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
-    rc = sqlite3_step(c->pStmt);
-    if( rc==SQLITE_ROW ){   /* the case we expect */
-      c->eof = 0;
-      return SQLITE_OK;
-    }
-    /* an error occurred; abort */
-    return rc==SQLITE_DONE ? SQLITE_ERROR : rc;
-  }
-}
-
-
-/* Return a DocList corresponding to the query term *pTerm.  If *pTerm
-** is the first term of a phrase query, go ahead and evaluate the phrase
-** query and return the doclist for the entire phrase query.
-**
-** The result is stored in pTerm->doclist.
-*/
-static int docListOfTerm(
-  fulltext_vtab *v,     /* The full text index */
-  int iColumn,          /* column to restrict to.  No restrition if >=nColumn */
-  QueryTerm *pQTerm,    /* Term we are looking for, or 1st term of a phrase */
-  DocList **ppResult    /* Write the result here */
-){
-  DocList *pLeft, *pRight, *pNew;
-  int i, rc;
-
-  pLeft = docListNew(DL_POSITIONS);
-  rc = term_select_all(v, iColumn, pQTerm->pTerm, pQTerm->nTerm, pLeft);
-  if( rc ){
-    docListDelete(pLeft);
-    return rc;
-  }
-  for(i=1; i<=pQTerm->nPhrase; i++){
-    pRight = docListNew(DL_POSITIONS);
-    rc = term_select_all(v, iColumn, pQTerm[i].pTerm, pQTerm[i].nTerm, pRight);
-    if( rc ){
-      docListDelete(pLeft);
-      return rc;
-    }
-    pNew = docListNew(i<pQTerm->nPhrase ? DL_POSITIONS : DL_DOCIDS);
-    docListPhraseMerge(pLeft, pRight, pNew);
-    docListDelete(pLeft);
-    docListDelete(pRight);
-    pLeft = pNew;
-  }
-  *ppResult = pLeft;
-  return SQLITE_OK;
-}
-
-/* Add a new term pTerm[0..nTerm-1] to the query *q.
-*/
-static void queryAdd(Query *q, const char *pTerm, int nTerm){
-  QueryTerm *t;
-  ++q->nTerms;
-  q->pTerms = realloc(q->pTerms, q->nTerms * sizeof(q->pTerms[0]));
-  if( q->pTerms==0 ){
-    q->nTerms = 0;
-    return;
-  }
-  t = &q->pTerms[q->nTerms - 1];
-  memset(t, 0, sizeof(*t));
-  t->pTerm = malloc(nTerm+1);
-  memcpy(t->pTerm, pTerm, nTerm);
-  t->pTerm[nTerm] = 0;
-  t->nTerm = nTerm;
-  t->isOr = q->nextIsOr;
-  q->nextIsOr = 0;
-  t->iColumn = q->nextColumn;
-  q->nextColumn = q->dfltColumn;
-}
-
-/*
-** Check to see if the string zToken[0...nToken-1] matches any
-** column name in the virtual table.   If it does,
-** return the zero-indexed column number.  If not, return -1.
-*/
-static int checkColumnSpecifier(
-  fulltext_vtab *pVtab,    /* The virtual table */
-  const char *zToken,      /* Text of the token */
-  int nToken               /* Number of characters in the token */
-){
-  int i;
-  for(i=0; i<pVtab->nColumn; i++){
-    if( memcmp(pVtab->azColumn[i], zToken, nToken)==0
-        && pVtab->azColumn[i][nToken]==0 ){
-      return i;
-    }
-  }
-  return -1;
-}
-
-/*
-** Parse the text at pSegment[0..nSegment-1].  Add additional terms
-** to the query being assemblied in pQuery.
-**
-** inPhrase is true if pSegment[0..nSegement-1] is contained within
-** double-quotes.  If inPhrase is true, then the first term
-** is marked with the number of terms in the phrase less one and
-** OR and "-" syntax is ignored.  If inPhrase is false, then every
-** term found is marked with nPhrase=0 and OR and "-" syntax is significant.
-*/
-static int tokenizeSegment(
-  sqlite3_tokenizer *pTokenizer,          /* The tokenizer to use */
-  const char *pSegment, int nSegment,     /* Query expression being parsed */
-  int inPhrase,                           /* True if within "..." */
-  Query *pQuery                           /* Append results here */
-){
-  const sqlite3_tokenizer_module *pModule = pTokenizer->pModule;
-  sqlite3_tokenizer_cursor *pCursor;
-  int firstIndex = pQuery->nTerms;
-  int iCol;
-  int nTerm = 1;
-  
-  int rc = pModule->xOpen(pTokenizer, pSegment, nSegment, &pCursor);
-  if( rc!=SQLITE_OK ) return rc;
-  pCursor->pTokenizer = pTokenizer;
-
-  while( 1 ){
-    const char *pToken;
-    int nToken, iBegin, iEnd, iPos;
-
-    rc = pModule->xNext(pCursor,
-                        &pToken, &nToken,
-                        &iBegin, &iEnd, &iPos);
-    if( rc!=SQLITE_OK ) break;
-    if( !inPhrase &&
-        pSegment[iEnd]==':' &&
-         (iCol = checkColumnSpecifier(pQuery->pFts, pToken, nToken))>=0 ){
-      pQuery->nextColumn = iCol;
-      continue;
-    }
-    if( !inPhrase && pQuery->nTerms>0 && nToken==2
-         && pSegment[iBegin]=='O' && pSegment[iBegin+1]=='R' ){
-      pQuery->nextIsOr = 1;
-      continue;
-    }
-    queryAdd(pQuery, pToken, nToken);
-    if( !inPhrase && iBegin>0 && pSegment[iBegin-1]=='-' ){
-      pQuery->pTerms[pQuery->nTerms-1].isNot = 1;
-    }
-    pQuery->pTerms[pQuery->nTerms-1].iPhrase = nTerm;
-    if( inPhrase ){
-      nTerm++;
-    }
-  }
-
-  if( inPhrase && pQuery->nTerms>firstIndex ){
-    pQuery->pTerms[firstIndex].nPhrase = pQuery->nTerms - firstIndex - 1;
-  }
-
-  return pModule->xClose(pCursor);
-}
-
-/* Parse a query string, yielding a Query object pQuery.
-**
-** The calling function will need to queryClear() to clean up
-** the dynamically allocated memory held by pQuery.
-*/
-static int parseQuery(
-  fulltext_vtab *v,        /* The fulltext index */
-  const char *zInput,      /* Input text of the query string */
-  int nInput,              /* Size of the input text */
-  int dfltColumn,          /* Default column of the index to match against */
-  Query *pQuery            /* Write the parse results here. */
-){
-  int iInput, inPhrase = 0;
-
-  if( zInput==0 ) nInput = 0;
-  if( nInput<0 ) nInput = strlen(zInput);
-  pQuery->nTerms = 0;
-  pQuery->pTerms = NULL;
-  pQuery->nextIsOr = 0;
-  pQuery->nextColumn = dfltColumn;
-  pQuery->dfltColumn = dfltColumn;
-  pQuery->pFts = v;
-
-  for(iInput=0; iInput<nInput; ++iInput){
-    int i;
-    for(i=iInput; i<nInput && zInput[i]!='"'; ++i){}
-    if( i>iInput ){
-      tokenizeSegment(v->pTokenizer, zInput+iInput, i-iInput, inPhrase,
-                       pQuery);
-    }
-    iInput = i;
-    if( i<nInput ){
-      assert( zInput[i]=='"' );
-      inPhrase = !inPhrase;
-    }
-  }
-
-  if( inPhrase ){
-    /* unmatched quote */
-    queryClear(pQuery);
-    return SQLITE_ERROR;
-  }
-  return SQLITE_OK;
-}
-
-/* Perform a full-text query using the search expression in
-** zInput[0..nInput-1].  Return a list of matching documents
-** in pResult.
-**
-** Queries must match column iColumn.  Or if iColumn>=nColumn
-** they are allowed to match against any column.
-*/
-static int fulltextQuery(
-  fulltext_vtab *v,      /* The full text index */
-  int iColumn,           /* Match against this column by default */
-  const char *zInput,    /* The query string */
-  int nInput,            /* Number of bytes in zInput[] */
-  DocList **pResult,     /* Write the result doclist here */
-  Query *pQuery          /* Put parsed query string here */
-){
-  int i, iNext, rc;
-  DocList *pLeft = NULL;
-  DocList *pRight, *pNew, *pOr;
-  int nNot = 0;
-  QueryTerm *aTerm;
-
-  rc = parseQuery(v, zInput, nInput, iColumn, pQuery);
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Merge AND terms. */
-  aTerm = pQuery->pTerms;
-  for(i = 0; i<pQuery->nTerms; i=iNext){
-    if( aTerm[i].isNot ){
-      /* Handle all NOT terms in a separate pass */
-      nNot++;
-      iNext = i + aTerm[i].nPhrase+1;
-      continue;
-    }
-    iNext = i + aTerm[i].nPhrase + 1;
-    rc = docListOfTerm(v, aTerm[i].iColumn, &aTerm[i], &pRight);
-    if( rc ){
-      queryClear(pQuery);
-      return rc;
-    }
-    while( iNext<pQuery->nTerms && aTerm[iNext].isOr ){
-      rc = docListOfTerm(v, aTerm[iNext].iColumn, &aTerm[iNext], &pOr);
-      iNext += aTerm[iNext].nPhrase + 1;
-      if( rc ){
-        queryClear(pQuery);
-        return rc;
-      }
-      pNew = docListNew(DL_DOCIDS);
-      docListOrMerge(pRight, pOr, pNew);
-      docListDelete(pRight);
-      docListDelete(pOr);
-      pRight = pNew;
-    }
-    if( pLeft==0 ){
-      pLeft = pRight;
-    }else{
-      pNew = docListNew(DL_DOCIDS);
-      docListAndMerge(pLeft, pRight, pNew);
-      docListDelete(pRight);
-      docListDelete(pLeft);
-      pLeft = pNew;
-    }
-  }
-
-  if( nNot && pLeft==0 ){
-    /* We do not yet know how to handle a query of only NOT terms */
-    return SQLITE_ERROR;
-  }
-
-  /* Do the EXCEPT terms */
-  for(i=0; i<pQuery->nTerms;  i += aTerm[i].nPhrase + 1){
-    if( !aTerm[i].isNot ) continue;
-    rc = docListOfTerm(v, aTerm[i].iColumn, &aTerm[i], &pRight);
-    if( rc ){
-      queryClear(pQuery);
-      docListDelete(pLeft);
-      return rc;
-    }
-    pNew = docListNew(DL_DOCIDS);
-    docListExceptMerge(pLeft, pRight, pNew);
-    docListDelete(pRight);
-    docListDelete(pLeft);
-    pLeft = pNew;
-  }
-
-  *pResult = pLeft;
-  return rc;
-}
-
-/*
-** This is the xFilter interface for the virtual table.  See
-** the virtual table xFilter method documentation for additional
-** information.
-**
-** If idxNum==QUERY_GENERIC then do a full table scan against
-** the %_content table.
-**
-** If idxNum==QUERY_ROWID then do a rowid lookup for a single entry
-** in the %_content table.
-**
-** If idxNum>=QUERY_FULLTEXT then use the full text index.  The
-** column on the left-hand side of the MATCH operator is column
-** number idxNum-QUERY_FULLTEXT, 0 indexed.  argv[0] is the right-hand
-** side of the MATCH operator.
-*/
-/* TODO(shess) Upgrade the cursor initialization and destruction to
-** account for fulltextFilter() being called multiple times on the
-** same cursor.  The current solution is very fragile.  Apply fix to
-** fts2 as appropriate.
-*/
-static int fulltextFilter(
-  sqlite3_vtab_cursor *pCursor,     /* The cursor used for this query */
-  int idxNum, const char *idxStr,   /* Which indexing scheme to use */
-  int argc, sqlite3_value **argv    /* Arguments for the indexing scheme */
-){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  fulltext_vtab *v = cursor_vtab(c);
-  int rc;
-  char *zSql;
-
-  TRACE(("FTS1 Filter %p\n",pCursor));
-
-  zSql = sqlite3_mprintf("select rowid, * from %%_content %s",
-                          idxNum==QUERY_GENERIC ? "" : "where rowid=?");
-  sqlite3_finalize(c->pStmt);
-  rc = sql_prepare(v->db, v->zDb, v->zName, &c->pStmt, zSql);
-  sqlite3_free(zSql);
-  if( rc!=SQLITE_OK ) return rc;
-
-  c->iCursorType = idxNum;
-  switch( idxNum ){
-    case QUERY_GENERIC:
-      break;
-
-    case QUERY_ROWID:
-      rc = sqlite3_bind_int64(c->pStmt, 1, sqlite3_value_int64(argv[0]));
-      if( rc!=SQLITE_OK ) return rc;
-      break;
-
-    default:   /* full-text search */
-    {
-      const char *zQuery = (const char *)sqlite3_value_text(argv[0]);
-      DocList *pResult;
-      assert( idxNum<=QUERY_FULLTEXT+v->nColumn);
-      assert( argc==1 );
-      queryClear(&c->q);
-      rc = fulltextQuery(v, idxNum-QUERY_FULLTEXT, zQuery, -1, &pResult, &c->q);
-      if( rc!=SQLITE_OK ) return rc;
-      if( c->result.pDoclist!=NULL ) docListDelete(c->result.pDoclist);
-      readerInit(&c->result, pResult);
-      break;
-    }
-  }
-
-  return fulltextNext(pCursor);
-}
-
-/* This is the xEof method of the virtual table.  The SQLite core
-** calls this routine to find out if it has reached the end of
-** a query's results set.
-*/
-static int fulltextEof(sqlite3_vtab_cursor *pCursor){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  return c->eof;
-}
-
-/* This is the xColumn method of the virtual table.  The SQLite
-** core calls this method during a query when it needs the value
-** of a column from the virtual table.  This method needs to use
-** one of the sqlite3_result_*() routines to store the requested
-** value back in the pContext.
-*/
-static int fulltextColumn(sqlite3_vtab_cursor *pCursor,
-                          sqlite3_context *pContext, int idxCol){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-  fulltext_vtab *v = cursor_vtab(c);
-
-  if( idxCol<v->nColumn ){
-    sqlite3_value *pVal = sqlite3_column_value(c->pStmt, idxCol+1);
-    sqlite3_result_value(pContext, pVal);
-  }else if( idxCol==v->nColumn ){
-    /* The extra column whose name is the same as the table.
-    ** Return a blob which is a pointer to the cursor
-    */
-    sqlite3_result_blob(pContext, &c, sizeof(c), SQLITE_TRANSIENT);
-  }
-  return SQLITE_OK;
-}
-
-/* This is the xRowid method.  The SQLite core calls this routine to
-** retrive the rowid for the current row of the result set.  The
-** rowid should be written to *pRowid.
-*/
-static int fulltextRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
-  fulltext_cursor *c = (fulltext_cursor *) pCursor;
-
-  *pRowid = sqlite3_column_int64(c->pStmt, 0);
-  return SQLITE_OK;
-}
-
-/* Add all terms in [zText] to the given hash table.  If [iColumn] > 0,
- * we also store positions and offsets in the hash table using the given
- * column number. */
-static int buildTerms(fulltext_vtab *v, fts1Hash *terms, sqlite_int64 iDocid,
-                      const char *zText, int iColumn){
-  sqlite3_tokenizer *pTokenizer = v->pTokenizer;
-  sqlite3_tokenizer_cursor *pCursor;
-  const char *pToken;
-  int nTokenBytes;
-  int iStartOffset, iEndOffset, iPosition;
-  int rc;
-
-  rc = pTokenizer->pModule->xOpen(pTokenizer, zText, -1, &pCursor);
-  if( rc!=SQLITE_OK ) return rc;
-
-  pCursor->pTokenizer = pTokenizer;
-  while( SQLITE_OK==pTokenizer->pModule->xNext(pCursor,
-                                               &pToken, &nTokenBytes,
-                                               &iStartOffset, &iEndOffset,
-                                               &iPosition) ){
-    DocList *p;
-
-    /* Positions can't be negative; we use -1 as a terminator internally. */
-    if( iPosition<0 ){
-      pTokenizer->pModule->xClose(pCursor);
-      return SQLITE_ERROR;
-    }
-
-    p = fts1HashFind(terms, pToken, nTokenBytes);
-    if( p==NULL ){
-      p = docListNew(DL_DEFAULT);
-      docListAddDocid(p, iDocid);
-      fts1HashInsert(terms, pToken, nTokenBytes, p);
-    }
-    if( iColumn>=0 ){
-      docListAddPosOffset(p, iColumn, iPosition, iStartOffset, iEndOffset);
-    }
-  }
-
-  /* TODO(shess) Check return?  Should this be able to cause errors at
-  ** this point?  Actually, same question about sqlite3_finalize(),
-  ** though one could argue that failure there means that the data is
-  ** not durable.  *ponder*
-  */
-  pTokenizer->pModule->xClose(pCursor);
-  return rc;
-}
-
-/* Update the %_terms table to map the term [pTerm] to the given rowid. */
-static int index_insert_term(fulltext_vtab *v, const char *pTerm, int nTerm,
-                             DocList *d){
-  sqlite_int64 iIndexRow;
-  DocList doclist;
-  int iSegment = 0, rc;
-
-  rc = term_select(v, pTerm, nTerm, iSegment, &iIndexRow, &doclist);
-  if( rc==SQLITE_DONE ){
-    docListInit(&doclist, DL_DEFAULT, 0, 0);
-    docListUpdate(&doclist, d);
-    /* TODO(shess) Consider length(doclist)>CHUNK_MAX? */
-    rc = term_insert(v, NULL, pTerm, nTerm, iSegment, &doclist);
-    goto err;
-  }
-  if( rc!=SQLITE_ROW ) return SQLITE_ERROR;
-
-  docListUpdate(&doclist, d);
-  if( doclist.nData<=CHUNK_MAX ){
-    rc = term_update(v, iIndexRow, &doclist);
-    goto err;
-  }
-
-  /* Doclist doesn't fit, delete what's there, and accumulate
-  ** forward.
-  */
-  rc = term_delete(v, iIndexRow);
-  if( rc!=SQLITE_OK ) goto err;
-
-  /* Try to insert the doclist into a higher segment bucket.  On
-  ** failure, accumulate existing doclist with the doclist from that
-  ** bucket, and put results in the next bucket.
-  */
-  iSegment++;
-  while( (rc=term_insert(v, &iIndexRow, pTerm, nTerm, iSegment,
-                         &doclist))!=SQLITE_OK ){
-    sqlite_int64 iSegmentRow;
-    DocList old;
-    int rc2;
-
-    /* Retain old error in case the term_insert() error was really an
-    ** error rather than a bounced insert.
-    */
-    rc2 = term_select(v, pTerm, nTerm, iSegment, &iSegmentRow, &old);
-    if( rc2!=SQLITE_ROW ) goto err;
-
-    rc = term_delete(v, iSegmentRow);
-    if( rc!=SQLITE_OK ) goto err;
-
-    /* Reusing lowest-number deleted row keeps the index smaller. */
-    if( iSegmentRow<iIndexRow ) iIndexRow = iSegmentRow;
-
-    /* doclist contains the newer data, so accumulate it over old.
-    ** Then steal accumulated data for doclist.
-    */
-    docListAccumulate(&old, &doclist);
-    docListDestroy(&doclist);
-    doclist = old;
-
-    iSegment++;
-  }
-
- err:
-  docListDestroy(&doclist);
-  return rc;
-}
-
-/* Add doclists for all terms in [pValues] to the hash table [terms]. */
-static int insertTerms(fulltext_vtab *v, fts1Hash *terms, sqlite_int64 iRowid,
-                sqlite3_value **pValues){
-  int i;
-  for(i = 0; i < v->nColumn ; ++i){
-    char *zText = (char*)sqlite3_value_text(pValues[i]);
-    int rc = buildTerms(v, terms, iRowid, zText, i);
-    if( rc!=SQLITE_OK ) return rc;
-  }
-  return SQLITE_OK;
-}
-
-/* Add empty doclists for all terms in the given row's content to the hash
- * table [pTerms]. */
-static int deleteTerms(fulltext_vtab *v, fts1Hash *pTerms, sqlite_int64 iRowid){
-  const char **pValues;
-  int i;
-
-  int rc = content_select(v, iRowid, &pValues);
-  if( rc!=SQLITE_OK ) return rc;
-
-  for(i = 0 ; i < v->nColumn; ++i) {
-    rc = buildTerms(v, pTerms, iRowid, pValues[i], -1);
-    if( rc!=SQLITE_OK ) break;
-  }
-
-  freeStringArray(v->nColumn, pValues);
-  return SQLITE_OK;
-}
-
-/* Insert a row into the %_content table; set *piRowid to be the ID of the
- * new row.  Fill [pTerms] with new doclists for the %_term table. */
-static int index_insert(fulltext_vtab *v, sqlite3_value *pRequestRowid,
-                        sqlite3_value **pValues,
-                        sqlite_int64 *piRowid, fts1Hash *pTerms){
-  int rc;
-
-  rc = content_insert(v, pRequestRowid, pValues);  /* execute an SQL INSERT */
-  if( rc!=SQLITE_OK ) return rc;
-  *piRowid = sqlite3_last_insert_rowid(v->db);
-  return insertTerms(v, pTerms, *piRowid, pValues);
-}
-
-/* Delete a row from the %_content table; fill [pTerms] with empty doclists
- * to be written to the %_term table. */
-static int index_delete(fulltext_vtab *v, sqlite_int64 iRow, fts1Hash *pTerms){
-  int rc = deleteTerms(v, pTerms, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-  return content_delete(v, iRow);  /* execute an SQL DELETE */
-}
-
-/* Update a row in the %_content table; fill [pTerms] with new doclists for the
- * %_term table. */
-static int index_update(fulltext_vtab *v, sqlite_int64 iRow,
-                        sqlite3_value **pValues, fts1Hash *pTerms){
-  /* Generate an empty doclist for each term that previously appeared in this
-   * row. */
-  int rc = deleteTerms(v, pTerms, iRow);
-  if( rc!=SQLITE_OK ) return rc;
-
-  rc = content_update(v, pValues, iRow);  /* execute an SQL UPDATE */
-  if( rc!=SQLITE_OK ) return rc;
-
-  /* Now add positions for terms which appear in the updated row. */
-  return insertTerms(v, pTerms, iRow, pValues);
-}
-
-/* This function implements the xUpdate callback; it is the top-level entry
- * point for inserting, deleting or updating a row in a full-text table. */
-static int fulltextUpdate(sqlite3_vtab *pVtab, int nArg, sqlite3_value **ppArg,
-                   sqlite_int64 *pRowid){
-  fulltext_vtab *v = (fulltext_vtab *) pVtab;
-  fts1Hash terms;   /* maps term string -> PosList */
-  int rc;
-  fts1HashElem *e;
-
-  TRACE(("FTS1 Update %p\n", pVtab));
-  
-  fts1HashInit(&terms, FTS1_HASH_STRING, 1);
-
-  if( nArg<2 ){
-    rc = index_delete(v, sqlite3_value_int64(ppArg[0]), &terms);
-  } else if( sqlite3_value_type(ppArg[0]) != SQLITE_NULL ){
-    /* An update:
-     * ppArg[0] = old rowid
-     * ppArg[1] = new rowid
-     * ppArg[2..2+v->nColumn-1] = values
-     * ppArg[2+v->nColumn] = value for magic column (we ignore this)
-     */
-    sqlite_int64 rowid = sqlite3_value_int64(ppArg[0]);
-    if( sqlite3_value_type(ppArg[1]) != SQLITE_INTEGER ||
-      sqlite3_value_int64(ppArg[1]) != rowid ){
-      rc = SQLITE_ERROR;  /* we don't allow changing the rowid */
-    } else {
-      assert( nArg==2+v->nColumn+1);
-      rc = index_update(v, rowid, &ppArg[2], &terms);
-    }
-  } else {
-    /* An insert:
-     * ppArg[1] = requested rowid
-     * ppArg[2..2+v->nColumn-1] = values
-     * ppArg[2+v->nColumn] = value for magic column (we ignore this)
-     */
-    assert( nArg==2+v->nColumn+1);
-    rc = index_insert(v, ppArg[1], &ppArg[2], pRowid, &terms);
-  }
-
-  if( rc==SQLITE_OK ){
-    /* Write updated doclists to disk. */
-    for(e=fts1HashFirst(&terms); e; e=fts1HashNext(e)){
-      DocList *p = fts1HashData(e);
-      rc = index_insert_term(v, fts1HashKey(e), fts1HashKeysize(e), p);
-      if( rc!=SQLITE_OK ) break;
-    }
-  }
-
-  /* clean up */
-  for(e=fts1HashFirst(&terms); e; e=fts1HashNext(e)){
-    DocList *p = fts1HashData(e);
-    docListDelete(p);
-  }
-  fts1HashClear(&terms);
-
-  return rc;
-}
-
-/*
-** Implementation of the snippet() function for FTS1
-*/
-static void snippetFunc(
-  sqlite3_context *pContext,
-  int argc,
-  sqlite3_value **argv
-){
-  fulltext_cursor *pCursor;
-  if( argc<1 ) return;
-  if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-      sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    sqlite3_result_error(pContext, "illegal first argument to html_snippet",-1);
-  }else{
-    const char *zStart = "<b>";
-    const char *zEnd = "</b>";
-    const char *zEllipsis = "<b>...</b>";
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    if( argc>=2 ){
-      zStart = (const char*)sqlite3_value_text(argv[1]);
-      if( argc>=3 ){
-        zEnd = (const char*)sqlite3_value_text(argv[2]);
-        if( argc>=4 ){
-          zEllipsis = (const char*)sqlite3_value_text(argv[3]);
-        }
-      }
-    }
-    snippetAllOffsets(pCursor);
-    snippetText(pCursor, zStart, zEnd, zEllipsis);
-    sqlite3_result_text(pContext, pCursor->snippet.zSnippet,
-                        pCursor->snippet.nSnippet, SQLITE_STATIC);
-  }
-}
-
-/*
-** Implementation of the offsets() function for FTS1
-*/
-static void snippetOffsetsFunc(
-  sqlite3_context *pContext,
-  int argc,
-  sqlite3_value **argv
-){
-  fulltext_cursor *pCursor;
-  if( argc<1 ) return;
-  if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
-      sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
-    sqlite3_result_error(pContext, "illegal first argument to offsets",-1);
-  }else{
-    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
-    snippetAllOffsets(pCursor);
-    snippetOffsetText(&pCursor->snippet);
-    sqlite3_result_text(pContext,
-                        pCursor->snippet.zOffset, pCursor->snippet.nOffset,
-                        SQLITE_STATIC);
-  }
-}
-
-/*
-** This routine implements the xFindFunction method for the FTS1
-** virtual table.
-*/
-static int fulltextFindFunction(
-  sqlite3_vtab *pVtab,
-  int nArg,
-  const char *zName,
-  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
-  void **ppArg
-){
-  if( strcmp(zName,"snippet")==0 ){
-    *pxFunc = snippetFunc;
-    return 1;
-  }else if( strcmp(zName,"offsets")==0 ){
-    *pxFunc = snippetOffsetsFunc;
-    return 1;
-  }
-  return 0;
-}
-
-/*
-** Rename an fts1 table.
-*/
-static int fulltextRename(
-  sqlite3_vtab *pVtab,
-  const char *zName
-){
-  fulltext_vtab *p = (fulltext_vtab *)pVtab;
-  int rc = SQLITE_NOMEM;
-  char *zSql = sqlite3_mprintf(
-    "ALTER TABLE %Q.'%q_content'  RENAME TO '%q_content';"
-    "ALTER TABLE %Q.'%q_term' RENAME TO '%q_term';"
-    , p->zDb, p->zName, zName
-    , p->zDb, p->zName, zName
-  );
-  if( zSql ){
-    rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
-    sqlite3_free(zSql);
-  }
-  return rc;
-}
-
-static const sqlite3_module fulltextModule = {
-  /* iVersion      */ 0,
-  /* xCreate       */ fulltextCreate,
-  /* xConnect      */ fulltextConnect,
-  /* xBestIndex    */ fulltextBestIndex,
-  /* xDisconnect   */ fulltextDisconnect,
-  /* xDestroy      */ fulltextDestroy,
-  /* xOpen         */ fulltextOpen,
-  /* xClose        */ fulltextClose,
-  /* xFilter       */ fulltextFilter,
-  /* xNext         */ fulltextNext,
-  /* xEof          */ fulltextEof,
-  /* xColumn       */ fulltextColumn,
-  /* xRowid        */ fulltextRowid,
-  /* xUpdate       */ fulltextUpdate,
-  /* xBegin        */ 0, 
-  /* xSync         */ 0,
-  /* xCommit       */ 0,
-  /* xRollback     */ 0,
-  /* xFindFunction */ fulltextFindFunction,
-  /* xRename       */ fulltextRename,
-};
-
-int sqlite3Fts1Init(sqlite3 *db){
-  sqlite3_overload_function(db, "snippet", -1);
-  sqlite3_overload_function(db, "offsets", -1);
-  return sqlite3_create_module(db, "fts1", &fulltextModule, 0);
-}
-
-#if !SQLITE_CORE
-int sqlite3_extension_init(sqlite3 *db, char **pzErrMsg,
-                           const sqlite3_api_routines *pApi){
-  SQLITE_EXTENSION_INIT2(pApi)
-  return sqlite3Fts1Init(db);
-}
-#endif
-
-#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS1) */