SQLite

    case FTS5_COMMIT:
      assert( p->ts.eState==2 );
      p->ts.eState = 0;
      break;

    case FTS5_ROLLBACK:
      assert( p->ts.eState==1 || p->ts.eState==2 );
      assert( p->ts.eState==1 || p->ts.eState==2 || p->ts.eState==0 );
      p->ts.eState = 0;
      break;

    case FTS5_SAVEPOINT:
      assert( p->ts.eState==1 );
      assert( iSavepoint>=0 );
      assert( iSavepoint>p->ts.iSavepoint );

static int fts5ConfigParseSpecial(
  Fts5Config *pConfig,            /* Configuration object to update */
  char *zCmd,                     /* Special command to parse */
  char *zArg,                     /* Argument to parse */
  char **pzErr                    /* OUT: Error message */
){
  if( sqlite3_stricmp(zCmd, "prefix")==0 ){
    const int nByte = sizeof(int) * FTS5_MAX_PREFIX_INDEXES;
    int rc = SQLITE_OK;
    char *p;
    if( pConfig->aPrefix ){
      *pzErr = sqlite3_mprintf("multiple prefix=... directives");
      return SQLITE_ERROR;
      rc = SQLITE_ERROR;
    }else{
      pConfig->aPrefix = sqlite3Fts5MallocZero(&rc, nByte);
    }
    pConfig->aPrefix = sqlite3_malloc(sizeof(int) * FTS5_MAX_PREFIX_INDEXES);
    p = zArg;
    while( p[0] ){
    while( rc==SQLITE_OK && p[0] ){
      int nPre = 0;
      while( p[0]==' ' ) p++;
      while( p[0]>='0' && p[0]<='9' && nPre<1000 ){
        nPre = nPre*10 + (p[0] - '0');
        p++;
      }
      while( p[0]==' ' ) p++;
      if( p[0]==',' ){
        p++;
      }else if( p[0] ){
        *pzErr = sqlite3_mprintf("malformed prefix=... directive");
        return SQLITE_ERROR;
        rc = SQLITE_ERROR;
      }
      if( nPre==0 || nPre>=1000 ){
      if( rc==SQLITE_OK && (nPre==0 || nPre>=1000) ){
        *pzErr = sqlite3_mprintf("prefix length out of range: %d", nPre);
        return SQLITE_ERROR;
        rc = SQLITE_ERROR;
      }
      pConfig->aPrefix[pConfig->nPrefix] = nPre;
      pConfig->nPrefix++;
    }
    return SQLITE_OK;
    return rc;
  }

  *pzErr = sqlite3_mprintf("unrecognized directive: \"%s\"", zCmd);
  return SQLITE_ERROR;
}

/*

              rc = fts5ConfigParseSpecial(pRet, zDup, zArg, pzErr);
              sqlite3_free(zDup);
              zDup = 0;
            }
          }

          /* If it is not a special directive, it must be a column name. In
           ** this case, check that it is not the reserved column name "rank". */
          ** this case, check that it is not the reserved column name "rank". */
          if( zDup ){
            sqlite3Fts5Dequote(zDup);
            pRet->azCol[pRet->nCol++] = zDup;
            if( sqlite3_stricmp(zDup, FTS5_RANK_NAME)==0 ){
              *pzErr = sqlite3_mprintf("reserved fts5 column name: %s", zDup);
              rc = SQLITE_ERROR;
            }

  sqlite3Fts5ParserFree(pEngine, fts5ParseFree);

  assert( sParse.pExpr==0 || (sParse.rc==SQLITE_OK && sParse.zErr==0) );
  if( sParse.rc==SQLITE_OK ){
    *ppNew = pNew = sqlite3_malloc(sizeof(Fts5Expr));
    if( pNew==0 ){
      sParse.rc = SQLITE_NOMEM;
      sqlite3Fts5ParseNodeFree(sParse.pExpr);
    }else{
      pNew->pRoot = sParse.pExpr;
      pNew->pIndex = 0;
      pNew->apExprPhrase = sParse.apPhrase;
      pNew->nPhrase = sParse.nPhrase;
      sParse.apPhrase = 0;
    }

      pTerm = &pPhrase->aTerm[j];
      rc = sqlite3Fts5IndexQuery(
          pExpr->pIndex, pTerm->zTerm, strlen(pTerm->zTerm),
          (pTerm->bPrefix ? FTS5INDEX_QUERY_PREFIX : 0) |
          (pExpr->bAsc ? FTS5INDEX_QUERY_ASC : 0),
          &pTerm->pIter
      );
      assert( rc==SQLITE_OK || pTerm->pIter==0 );
      if( pTerm->pIter && sqlite3Fts5IterEof(pTerm->pIter) ){
      if( pTerm->pIter==0 || sqlite3Fts5IterEof(pTerm->pIter) ){
        pNode->bEof = 1;
        break;
      }
    }
  }

  return rc;

  int bPrefix                     /* True if there is a trailing "*" */
){
  Fts5Config *pConfig = pParse->pConfig;
  TokenCtx sCtx;                  /* Context object passed to callback */
  int rc;                         /* Tokenize return code */
  char *z = 0;

  memset(&sCtx, 0, sizeof(TokenCtx));
  sCtx.pPhrase = pPhrase;

  if( pPhrase==0 ){
    if( (pParse->nPhrase % 8)==0 ){
      int nByte = sizeof(Fts5ExprPhrase*) * (pParse->nPhrase + 8);
      Fts5ExprPhrase **apNew;
      apNew = (Fts5ExprPhrase**)sqlite3_realloc(pParse->apPhrase, nByte);
      if( apNew==0 ) return 0;
      if( apNew==0 ){
        pParse->rc = SQLITE_NOMEM;
        fts5ExprPhraseFree(pPhrase);
        return 0;
      }
      pParse->apPhrase = apNew;
    }
    pParse->nPhrase++;
  }

  pParse->rc = fts5ParseStringFromToken(pToken, &z);
  if( z==0 ) return 0;
  sqlite3Fts5Dequote(z);
  rc = fts5ParseStringFromToken(pToken, &z);
  if( rc==SQLITE_OK ){
    sqlite3Fts5Dequote(z);

  memset(&sCtx, 0, sizeof(TokenCtx));
  sCtx.pPhrase = pPhrase;
  rc = sqlite3Fts5Tokenize(pConfig, z, strlen(z), &sCtx, fts5ParseTokenize);
    rc = sqlite3Fts5Tokenize(pConfig, z, strlen(z), &sCtx, fts5ParseTokenize);
  }
  if( rc ){
    pParse->rc = rc;
    fts5ExprPhraseFree(sCtx.pPhrase);
    sCtx.pPhrase = 0;
  }else if( sCtx.pPhrase->nTerm>0 ){
    sCtx.pPhrase->aTerm[sCtx.pPhrase->nTerm-1].bPrefix = bPrefix;
  }

/*
** Allocate and return a buffer at least nByte bytes in size.
**
** If an OOM error is encountered, return NULL and set the error code in
** the Fts5Index handle passed as the first argument.
*/
static void *fts5IdxMalloc(Fts5Index *p, int nByte){
  void *pRet;
  assert( p->rc==SQLITE_OK );
  pRet = sqlite3_malloc(nByte);
  if( pRet==0 ){
    p->rc = SQLITE_NOMEM;
  }else{
    memset(pRet, 0, nByte);
  void *pRet = 0;
  if( p->rc==SQLITE_OK ){
    pRet = sqlite3_malloc(nByte);
    if( pRet==0 ){
      p->rc = SQLITE_NOMEM;
    }else{
      memset(pRet, 0, nByte);
    }
  }
  return pRet;
}

/*
** Compare the contents of the pLeft buffer with the pRight/nRight blob.
**

/*
** Close the read-only blob handle, if it is open.
*/
static void fts5CloseReader(Fts5Index *p){
  if( p->pReader ){
    sqlite3_blob_close(p->pReader);
    sqlite3_blob *pReader = p->pReader;
    p->pReader = 0;
    sqlite3_blob_close(pReader);
  }
}

static Fts5Data *fts5DataReadOrBuffer(
  Fts5Index *p, 
  Fts5Buffer *pBuf, 
  i64 iRowid

      );
    }

    if( rc==SQLITE_OK ){
      int nByte = sqlite3_blob_bytes(p->pReader);
      if( pBuf ){
        fts5BufferZero(pBuf);
        fts5BufferGrow(&rc, pBuf, nByte);
        rc = sqlite3_blob_read(p->pReader, pBuf->p, nByte, 0);
        if( rc==SQLITE_OK ) pBuf->n = nByte;
        if( SQLITE_OK==fts5BufferGrow(&rc, pBuf, nByte) ){
          rc = sqlite3_blob_read(p->pReader, pBuf->p, nByte, 0);
          if( rc==SQLITE_OK ) pBuf->n = nByte;
        }
      }else{
        pRet = (Fts5Data*)fts5IdxMalloc(p, sizeof(Fts5Data) + nByte);
        if( !pRet ) return 0;

        pRet->n = nByte;
        pRet->p = (u8*)&pRet[1];
        pRet->nRef = 1;

** Remove all records associated with segment iSegid in index iIdx.
*/
static void fts5DataRemoveSegment(Fts5Index *p, int iIdx, int iSegid){
  i64 iFirst = FTS5_SEGMENT_ROWID(iIdx, iSegid, 0, 0);
  i64 iLast = FTS5_SEGMENT_ROWID(iIdx, iSegid+1, 0, 0)-1;
  fts5DataDelete(p, iFirst, iLast);
}

/*
** Release a reference to an Fts5Structure object returned by an earlier 
** call to fts5StructureRead() or fts5StructureDecode().
*/
static void fts5StructureRelease(Fts5Structure *pStruct){
  if( pStruct ){
    int i;
    for(i=0; i<pStruct->nLevel; i++){
      sqlite3_free(pStruct->aLevel[i].aSeg);
    }
    sqlite3_free(pStruct);
  }
}

/*
** Deserialize and return the structure record currently stored in serialized
** form within buffer pData/nData.
**
** The Fts5Structure.aLevel[] and each Fts5StructureLevel.aSeg[] array
** are over-allocated by one slot. This allows the structure contents

        pLvl->nSeg = nTotal;
        for(iSeg=0; iSeg<nTotal; iSeg++){
          i += getVarint32(&pData[i], pLvl->aSeg[iSeg].iSegid);
          i += getVarint32(&pData[i], pLvl->aSeg[iSeg].nHeight);
          i += getVarint32(&pData[i], pLvl->aSeg[iSeg].pgnoFirst);
          i += getVarint32(&pData[i], pLvl->aSeg[iSeg].pgnoLast);
        }
      }else{
        fts5StructureRelease(pRet);
        pRet = 0;
      }
    }
  }

  *ppOut = pRet;
  return rc;
}

  p->rc = fts5StructureDecode(pData->p, pData->n, &iCookie, &pRet);

  if( p->rc==SQLITE_OK && p->pConfig->iCookie!=iCookie ){
    p->rc = sqlite3Fts5ConfigLoad(p->pConfig, iCookie);
  }

  fts5DataRelease(pData);
  if( p->rc!=SQLITE_OK ){
    fts5StructureRelease(pRet);
    pRet = 0;
  }
  return pRet;
}

/*
** Release a reference to an Fts5Structure object returned by an earlier 
** call to fts5StructureRead() or fts5StructureDecode().
*/
static void fts5StructureRelease(Fts5Structure *pStruct){
  int i;
  for(i=0; i<pStruct->nLevel; i++){
    sqlite3_free(pStruct->aLevel[i].aSeg);
  }
  sqlite3_free(pStruct);
}

/*
** Return the total number of segments in index structure pStruct.
*/
static int fts5StructureCountSegments(Fts5Structure *pStruct){
  int nSegment = 0;               /* Total number of segments */
  int iLvl;                       /* Used to iterate through levels */

/*
** Serialize and store the "structure" record for index iIdx.
**
** If an error occurs, leave an error code in the Fts5Index object. If an
** error has already occurred, this function is a no-op.
*/
static void fts5StructureWrite(Fts5Index *p, int iIdx, Fts5Structure *pStruct){
  if( p->rc==SQLITE_OK ){
  int nSegment;                   /* Total number of segments */
  Fts5Buffer buf;                 /* Buffer to serialize record into */
  int iLvl;                       /* Used to iterate through levels */
  int iCookie;                    /* Cookie value to store */
    int nSegment;                 /* Total number of segments */
    Fts5Buffer buf;               /* Buffer to serialize record into */
    int iLvl;                     /* Used to iterate through levels */
    int iCookie;                  /* Cookie value to store */

  nSegment = fts5StructureCountSegments(pStruct);
  memset(&buf, 0, sizeof(Fts5Buffer));
    nSegment = fts5StructureCountSegments(pStruct);
    memset(&buf, 0, sizeof(Fts5Buffer));

  /* Append the current configuration cookie */
  iCookie = p->pConfig->iCookie;
  if( iCookie<0 ) iCookie = 0;
  fts5BufferAppend32(&p->rc, &buf, iCookie);
    /* Append the current configuration cookie */
    iCookie = p->pConfig->iCookie;
    if( iCookie<0 ) iCookie = 0;
    fts5BufferAppend32(&p->rc, &buf, iCookie);

  fts5BufferAppendVarint(&p->rc, &buf, pStruct->nLevel);
  fts5BufferAppendVarint(&p->rc, &buf, nSegment);
  fts5BufferAppendVarint(&p->rc, &buf, (i64)pStruct->nWriteCounter);
    fts5BufferAppendVarint(&p->rc, &buf, pStruct->nLevel);
    fts5BufferAppendVarint(&p->rc, &buf, nSegment);
    fts5BufferAppendVarint(&p->rc, &buf, (i64)pStruct->nWriteCounter);

  for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
    int iSeg;                     /* Used to iterate through segments */
    Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
    fts5BufferAppendVarint(&p->rc, &buf, pLvl->nMerge);
    fts5BufferAppendVarint(&p->rc, &buf, pLvl->nSeg);
    assert( pLvl->nMerge<=pLvl->nSeg );
    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
      int iSeg;                     /* Used to iterate through segments */
      Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
      fts5BufferAppendVarint(&p->rc, &buf, pLvl->nMerge);
      fts5BufferAppendVarint(&p->rc, &buf, pLvl->nSeg);
      assert( pLvl->nMerge<=pLvl->nSeg );

    for(iSeg=0; iSeg<pLvl->nSeg; iSeg++){
      fts5BufferAppendVarint(&p->rc, &buf, pLvl->aSeg[iSeg].iSegid);
      fts5BufferAppendVarint(&p->rc, &buf, pLvl->aSeg[iSeg].nHeight);
      fts5BufferAppendVarint(&p->rc, &buf, pLvl->aSeg[iSeg].pgnoFirst);
      fts5BufferAppendVarint(&p->rc, &buf, pLvl->aSeg[iSeg].pgnoLast);
    }
  }
      for(iSeg=0; iSeg<pLvl->nSeg; iSeg++){
        fts5BufferAppendVarint(&p->rc, &buf, pLvl->aSeg[iSeg].iSegid);
        fts5BufferAppendVarint(&p->rc, &buf, pLvl->aSeg[iSeg].nHeight);
        fts5BufferAppendVarint(&p->rc, &buf, pLvl->aSeg[iSeg].pgnoFirst);
        fts5BufferAppendVarint(&p->rc, &buf, pLvl->aSeg[iSeg].pgnoLast);
      }
    }

  fts5DataWrite(p, FTS5_STRUCTURE_ROWID(iIdx), buf.p, buf.n);
  fts5BufferFree(&buf);
    fts5DataWrite(p, FTS5_STRUCTURE_ROWID(iIdx), buf.p, buf.n);
    fts5BufferFree(&buf);
  }
}

#if 0
static void fts5PrintStructure(const char *zCaption, Fts5Structure *pStruct){
  int rc = SQLITE_OK;
  Fts5Buffer buf;
  memset(&buf, 0, sizeof(buf));

    int res;
    pIter->iLeafOffset = fts5GetU16(&pIter->pLeaf->p[2]);
    fts5SegIterLoadTerm(p, pIter, 0);
    do {
      res = fts5BufferCompareBlob(&pIter->term, pTerm, nTerm);
      if( res>=0 ) break;
      fts5SegIterNext(p, pIter);
    }while( pIter->pLeaf );
    }while( pIter->pLeaf && p->rc==SQLITE_OK );

    if( bGe==0 && res ){
      /* Set iterator to point to EOF */
      fts5DataRelease(pIter->pLeaf);
      pIter->pLeaf = 0;
    }
  }

  if( bGe==0 ){
  if( p->rc==SQLITE_OK && bGe==0 ){
    pIter->flags |= FTS5_SEGITER_ONETERM;
    if( pIter->pLeaf ){
      if( flags & FTS5INDEX_QUERY_ASC ){
        pIter->flags |= FTS5_SEGITER_REVERSE;
      }
      if( bDlidx ){
        fts5SegIterLoadDlidx(p, iIdx, pIter);

*/
static void fts5IndexDiscardData(Fts5Index *p){
  assert( p->apHash || p->nPendingData==0 );
  if( p->apHash ){
    Fts5Config *pConfig = p->pConfig;
    int i;
    for(i=0; i<=pConfig->nPrefix; i++){
      sqlite3Fts5HashClear(p->apHash[i]);
      if( p->apHash[i] ) sqlite3Fts5HashClear(p->apHash[i]);
    }
    p->nPendingData = 0;
  }
}

/*
** Return the size of the prefix, in bytes, that buffer (nNew/pNew) shares

  Fts5Index *p, 
  Fts5SegWriter *pWriter,
  int nTerm, const u8 *pTerm 
){
  int nPrefix;                    /* Bytes of prefix compression for term */
  Fts5PageWriter *pPage = &pWriter->aWriter[0];

  assert( pPage->buf.n==0 || pPage->buf.n>4 );
  if( pPage->buf.n==0 ){
  assert( pPage==0 || pPage->buf.n==0 || pPage->buf.n>4 );
  if( pPage && pPage->buf.n==0 ){
    /* Zero the first term and first docid fields */
    static const u8 zero[] = { 0x00, 0x00, 0x00, 0x00 };
    fts5BufferAppendBlob(&p->rc, &pPage->buf, 4, zero);
    assert( pPage->term.n==0 );
  }
  if( p->rc ) return;
  

** Append a docid to the writers output. 
*/
static void fts5WriteAppendRowid(
  Fts5Index *p, 
  Fts5SegWriter *pWriter,
  i64 iRowid
){
  if( p->rc==SQLITE_OK ){
  Fts5PageWriter *pPage = &pWriter->aWriter[0];
    Fts5PageWriter *pPage = &pWriter->aWriter[0];

  /* If this is to be the first docid written to the page, set the 
  ** docid-pointer in the page-header. Also append a value to the dlidx
  ** buffer, in case a doclist-index is required.  */
  if( pWriter->bFirstRowidInPage ){
    fts5PutU16(pPage->buf.p, pPage->buf.n);
    fts5WriteDlidxAppend(p, pWriter, iRowid);
  }
    /* If this is to be the first docid written to the page, set the 
    ** docid-pointer in the page-header. Also append a value to the dlidx
    ** buffer, in case a doclist-index is required.  */
    if( pWriter->bFirstRowidInPage ){
      fts5PutU16(pPage->buf.p, pPage->buf.n);
      fts5WriteDlidxAppend(p, pWriter, iRowid);
    }

  /* Write the docid. */
  if( pWriter->bFirstRowidInDoclist || pWriter->bFirstRowidInPage ){
    fts5BufferAppendVarint(&p->rc, &pPage->buf, iRowid);
  }else{
    assert( iRowid<pWriter->iPrevRowid );
    fts5BufferAppendVarint(&p->rc, &pPage->buf, pWriter->iPrevRowid - iRowid);
  }
  pWriter->iPrevRowid = iRowid;
  pWriter->bFirstRowidInDoclist = 0;
  pWriter->bFirstRowidInPage = 0;
    /* Write the docid. */
    if( pWriter->bFirstRowidInDoclist || pWriter->bFirstRowidInPage ){
      fts5BufferAppendVarint(&p->rc, &pPage->buf, iRowid);
    }else{
      assert( p->rc || iRowid<pWriter->iPrevRowid );
      fts5BufferAppendVarint(&p->rc, &pPage->buf, pWriter->iPrevRowid - iRowid);
    }
    pWriter->iPrevRowid = iRowid;
    pWriter->bFirstRowidInDoclist = 0;
    pWriter->bFirstRowidInPage = 0;

  if( pPage->buf.n>=p->pConfig->pgsz ){
    fts5WriteFlushLeaf(p, pWriter);
    pWriter->bFirstRowidInPage = 1;
    if( pPage->buf.n>=p->pConfig->pgsz ){
      fts5WriteFlushLeaf(p, pWriter);
      pWriter->bFirstRowidInPage = 1;
    }
  }
}

static void fts5WriteAppendPoslistInt(
  Fts5Index *p, 
  Fts5SegWriter *pWriter,
  int iVal
){
  if( p->rc==SQLITE_OK ){
  Fts5PageWriter *pPage = &pWriter->aWriter[0];
  fts5BufferAppendVarint(&p->rc, &pPage->buf, iVal);
  if( pPage->buf.n>=p->pConfig->pgsz ){
    fts5WriteFlushLeaf(p, pWriter);
    pWriter->bFirstRowidInPage = 1;
    Fts5PageWriter *pPage = &pWriter->aWriter[0];
    fts5BufferAppendVarint(&p->rc, &pPage->buf, iVal);
    if( pPage->buf.n>=p->pConfig->pgsz ){
      fts5WriteFlushLeaf(p, pWriter);
      pWriter->bFirstRowidInPage = 1;
    }
  }
}

static void fts5WriteAppendPoslistData(
  Fts5Index *p, 
  Fts5SegWriter *pWriter, 
  const u8 *aData, 

static void fts5WriteFinish(
  Fts5Index *p, 
  Fts5SegWriter *pWriter,         /* Writer object */
  int *pnHeight,                  /* OUT: Height of the b-tree */
  int *pnLeaf                     /* OUT: Number of leaf pages in b-tree */
){
  int i;
  if( p->rc==SQLITE_OK ){
  *pnLeaf = pWriter->aWriter[0].pgno;
  if( *pnLeaf==1 && pWriter->aWriter[0].buf.n==0 ){
    *pnLeaf = 0;
    *pnHeight = 0;
  }else{
    fts5WriteFlushLeaf(p, pWriter);
    if( pWriter->nWriter==1 && pWriter->nEmpty>=FTS5_MIN_DLIDX_SIZE ){
      fts5WriteBtreeGrow(p, pWriter);
    }
    if( pWriter->nWriter>1 ){
      fts5WriteBtreeNEmpty(p, pWriter);
    }
    *pnHeight = pWriter->nWriter;
    *pnLeaf = pWriter->aWriter[0].pgno;
    if( *pnLeaf==1 && pWriter->aWriter[0].buf.n==0 ){
      *pnLeaf = 0;
      *pnHeight = 0;
    }else{
      fts5WriteFlushLeaf(p, pWriter);
      if( pWriter->nWriter==1 && pWriter->nEmpty>=FTS5_MIN_DLIDX_SIZE ){
        fts5WriteBtreeGrow(p, pWriter);
      }
      if( pWriter->nWriter>1 ){
        fts5WriteBtreeNEmpty(p, pWriter);
      }
      *pnHeight = pWriter->nWriter;

    for(i=1; i<pWriter->nWriter; i++){
      Fts5PageWriter *pPg = &pWriter->aWriter[i];
      fts5DataWrite(p, 
          FTS5_SEGMENT_ROWID(pWriter->iIdx, pWriter->iSegid, i, pPg->pgno), 
          pPg->buf.p, pPg->buf.n
      );
    }
  }
      for(i=1; i<pWriter->nWriter; i++){
        Fts5PageWriter *pPg = &pWriter->aWriter[i];
        fts5DataWrite(p, 
            FTS5_SEGMENT_ROWID(pWriter->iIdx, pWriter->iSegid, i, pPg->pgno), 
            pPg->buf.p, pPg->buf.n
        );
      }
    }
  }
  for(i=0; i<pWriter->nWriter; i++){
    Fts5PageWriter *pPg = &pWriter->aWriter[i];
    assert( pPg || p->rc!=SQLITE_OK );
    if( pPg ){
    fts5BufferFree(&pPg->term);
    fts5BufferFree(&pPg->buf);
      fts5BufferFree(&pPg->term);
      fts5BufferFree(&pPg->buf);
    }
  }
  sqlite3_free(pWriter->aWriter);
  sqlite3Fts5BufferFree(&pWriter->dlidx);
}

static void fts5WriteInit(
  Fts5Index *p, 

*/
static void fts5IndexWork(
  Fts5Index *p,                   /* FTS5 backend object */
  int iIdx,                       /* Index to work on */
  Fts5Structure **ppStruct,       /* IN/OUT: Current structure of index */
  int nLeaf                       /* Number of output leaves just written */
){
  if( p->rc==SQLITE_OK ){
  Fts5Structure *pStruct = *ppStruct;
  i64 nWrite;                     /* Initial value of write-counter */
  int nWork;                      /* Number of work-quanta to perform */
  int nRem;                       /* Number of leaf pages left to write */
    Fts5Structure *pStruct = *ppStruct;
    i64 nWrite;                   /* Initial value of write-counter */
    int nWork;                    /* Number of work-quanta to perform */
    int nRem;                     /* Number of leaf pages left to write */

  /* Update the write-counter. While doing so, set nWork. */
  nWrite = pStruct->nWriteCounter;
  nWork = ((nWrite + nLeaf) / p->nWorkUnit) - (nWrite / p->nWorkUnit);
  pStruct->nWriteCounter += nLeaf;
  nRem = p->nWorkUnit * nWork * pStruct->nLevel;
    /* Update the write-counter. While doing so, set nWork. */
    nWrite = pStruct->nWriteCounter;
    nWork = ((nWrite + nLeaf) / p->nWorkUnit) - (nWrite / p->nWorkUnit);
    pStruct->nWriteCounter += nLeaf;
    nRem = p->nWorkUnit * nWork * pStruct->nLevel;

  while( nRem>0 ){
    int iLvl;                   /* To iterate through levels */
    int iBestLvl = 0;           /* Level offering the most input segments */
    int nBest = 0;              /* Number of input segments on best level */
    while( nRem>0 ){
      int iLvl;                   /* To iterate through levels */
      int iBestLvl = 0;           /* Level offering the most input segments */
      int nBest = 0;              /* Number of input segments on best level */

    /* Set iBestLvl to the level to read input segments from. */
    assert( pStruct->nLevel>0 );
    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
      Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
      if( pLvl->nMerge ){
        if( pLvl->nMerge>nBest ){
          iBestLvl = iLvl;
          nBest = pLvl->nMerge;
        }
        break;
      }
      if( pLvl->nSeg>nBest ){
        nBest = pLvl->nSeg;
        iBestLvl = iLvl;
      }
    }
      /* Set iBestLvl to the level to read input segments from. */
      assert( pStruct->nLevel>0 );
      for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
        Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
        if( pLvl->nMerge ){
          if( pLvl->nMerge>nBest ){
            iBestLvl = iLvl;
            nBest = pLvl->nMerge;
          }
          break;
        }
        if( pLvl->nSeg>nBest ){
          nBest = pLvl->nSeg;
          iBestLvl = iLvl;
        }
      }

    /* If nBest is still 0, then the index must be empty. */
      /* If nBest is still 0, then the index must be empty. */
#ifdef SQLITE_DEBUG
    for(iLvl=0; nBest==0 && iLvl<pStruct->nLevel; iLvl++){
      assert( pStruct->aLevel[iLvl].nSeg==0 );
    }
      for(iLvl=0; nBest==0 && iLvl<pStruct->nLevel; iLvl++){
        assert( pStruct->aLevel[iLvl].nSeg==0 );
      }
#endif

    if( nBest<p->pConfig->nAutomerge 
     && pStruct->aLevel[iBestLvl].nMerge==0 
    ){
      break;
    }
    fts5IndexMergeLevel(p, iIdx, &pStruct, iBestLvl, &nRem);
    fts5StructurePromote(p, iBestLvl+1, pStruct);
    assert( nRem==0 || p->rc==SQLITE_OK );
    *ppStruct = pStruct;
      if( nBest<p->pConfig->nAutomerge 
          && pStruct->aLevel[iBestLvl].nMerge==0 
        ){
        break;
      }
      fts5IndexMergeLevel(p, iIdx, &pStruct, iBestLvl, &nRem);
      fts5StructurePromote(p, iBestLvl+1, pStruct);
      assert( nRem==0 || p->rc==SQLITE_OK );
      *ppStruct = pStruct;
    }
  }
}

static void fts5IndexCrisisMerge(
  Fts5Index *p,                   /* FTS5 backend object */
  int iIdx,                       /* Index to work on */
  Fts5Structure **ppStruct        /* IN/OUT: Current structure of index */

static int fts5FlushNewEntry(
  void *pCtx, 
  i64 iRowid, 
  const u8 *aPoslist, 
  int nPoslist
){
  Fts5FlushCtx *p = (Fts5FlushCtx*)pCtx;
  int rc = SQLITE_OK;
  Fts5Index *pIdx = p->pIdx;

  /* Append the rowid itself */
  fts5WriteAppendRowid(p->pIdx, &p->writer, iRowid);
  fts5WriteAppendRowid(pIdx, &p->writer, iRowid);

  /* Append the size of the position list in bytes */
  fts5WriteAppendPoslistInt(p->pIdx, &p->writer, nPoslist);
  fts5WriteAppendPoslistInt(pIdx, &p->writer, nPoslist);

  /* And the poslist data */
  fts5WriteAppendPoslistData(p->pIdx, &p->writer, aPoslist, nPoslist);
  return rc;
  fts5WriteAppendPoslistData(pIdx, &p->writer, aPoslist, nPoslist);
  return pIdx->rc;
}

/*
** Flush the contents of in-memory hash table iHash to a new level-0 
** segment on disk. Also update the corresponding structure record.
**
** If an error occurs, set the Fts5Index.rc error code. If an error has 

*/
static void fts5MultiIterPoslist(
  Fts5Index *p,
  Fts5MultiSegIter *pMulti,
  int bSz,
  Fts5Buffer *pBuf
){
  if( p->rc==SQLITE_OK ){
  Fts5ChunkIter iter;
  Fts5SegIter *pSeg = &pMulti->aSeg[ pMulti->aFirst[1] ];
  assert( fts5MultiIterEof(p, pMulti)==0 );
  fts5ChunkIterInit(p, pSeg, &iter);
  if( fts5ChunkIterEof(p, &iter)==0 ){
    if( bSz ){
      fts5BufferAppendVarint(&p->rc, pBuf, iter.nRem);
    }
    while( fts5ChunkIterEof(p, &iter)==0 ){
      fts5BufferAppendBlob(&p->rc, pBuf, iter.n, iter.p);
      fts5ChunkIterNext(p, &iter);
    }
  }
  fts5ChunkIterRelease(&iter);
    Fts5ChunkIter iter;
    Fts5SegIter *pSeg = &pMulti->aSeg[ pMulti->aFirst[1] ];
    assert( fts5MultiIterEof(p, pMulti)==0 );
    fts5ChunkIterInit(p, pSeg, &iter);
    if( fts5ChunkIterEof(p, &iter)==0 ){
      if( bSz ){
        fts5BufferAppendVarint(&p->rc, pBuf, iter.nRem);
      }
      while( fts5ChunkIterEof(p, &iter)==0 ){
        fts5BufferAppendBlob(&p->rc, pBuf, iter.n, iter.p);
        fts5ChunkIterNext(p, &iter);
      }
    }
    fts5ChunkIterRelease(&iter);
  }
}

static void fts5DoclistIterNext(Fts5DoclistIter *pIter){
  if( pIter->i<pIter->n ){
    if( pIter->i ){
      i64 iDelta;
      pIter->i += getVarint(&pIter->a[pIter->i], (u64*)&iDelta);

** the offset of the method to call in the sqlite3_module structure.
**
** The array is cleared after invoking the callbacks. 
*/
static void callFinaliser(sqlite3 *db, int offset){
  int i;
  if( db->aVTrans ){
    VTable **aVTrans = db->aVTrans;
    db->aVTrans = 0;
    for(i=0; i<db->nVTrans; i++){
      VTable *pVTab = db->aVTrans[i];
      VTable *pVTab = aVTrans[i];
      sqlite3_vtab *p = pVTab->pVtab;
      if( p ){
        int (*x)(sqlite3_vtab *);
        x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset);
        if( x ) x(p);
      }
      pVTab->iSavepoint = 0;
      sqlite3VtabUnlock(pVTab);
    }
    sqlite3DbFree(db, db->aVTrans);
    sqlite3DbFree(db, aVTrans);
    db->nVTrans = 0;
    db->aVTrans = 0;
  }
}

/*
** Invoke the xSync method of all virtual tables in the sqlite3.aVTrans
** array. Return the error code for the first error that occurs, or
** SQLITE_OK if all xSync operations are successful.

set testprefix fts5fault1

# If SQLITE_ENABLE_FTS3 is defined, omit this file.
ifcapable !fts5 {
  finish_test
  return
}

# Simple tests:
#
#   1: CREATE VIRTUAL TABLE
#   2: INSERT statement
#   3: DELETE statement
#   4: MATCH expressions
#

if 1 {

faultsim_save_and_close
do_faultsim_test 1 -prep {
  faultsim_restore_and_reopen
} -body {
  execsql { CREATE VIRTUAL TABLE t1 USING fts5(a) }
  execsql { CREATE VIRTUAL TABLE t1 USING fts5(a, b, prefix='1, 2, 3') }
} -test {
  faultsim_test_result {0 {}} 
}

reset_db
do_execsql_test 2.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(a, b, prefix='1, 2, 3');


}
faultsim_save_and_close
do_faultsim_test 2 -prep {
  faultsim_restore_and_reopen
} -body {
  execsql { 
    INSERT INTO t1 VALUES('a b c', 'a bc def ghij klmno');
  }
} -test {
  faultsim_test_result {0 {}} 
}

reset_db
do_execsql_test 3.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(a, b, prefix='1, 2, 3');
  INSERT INTO t1 VALUES('a b c', 'a bc def ghij klmno');
}
faultsim_save_and_close
do_faultsim_test 3 -prep {
  faultsim_restore_and_reopen
} -body {
  execsql { DELETE FROM t1 }
} -test {
  faultsim_test_result {0 {}} 
}

}

reset_db
do_execsql_test 4.0 {
  CREATE VIRTUAL TABLE t2 USING fts5(a, b);
  INSERT INTO t2 VALUES('m f a jj th q jr ar',   'hj n h h sg j i m');
  INSERT INTO t2 VALUES('nr s t g od j kf h',    'sb h aq rg op rb n nl');
  INSERT INTO t2 VALUES('do h h pb p p q fr',    'c rj qs or cr a l i');
  INSERT INTO t2 VALUES('lk gp t i lq mq qm p',  'h mr g f op ld aj h');
  INSERT INTO t2 VALUES('ct d sq kc qi k f j',   'sn gh c of g s qt q');
  INSERT INTO t2 VALUES('d ea d d om mp s ab',   'dm hg l df cm ft pa c');
  INSERT INTO t2 VALUES('tc dk c jn n t sr ge',  'a a kn bc n i af h');
  INSERT INTO t2 VALUES('ie ii d i b sa qo rf',  'a h m aq i b m fn');
  INSERT INTO t2 VALUES('gs r fo a er m h li',   'tm c p gl eb ml q r');
  INSERT INTO t2 VALUES('k fe fd rd a gi ho kk', 'ng m c r d ml rm r');
}
faultsim_save_and_close

foreach {tn expr res} {
  1 { dk  }           7
  2 { m f }           1
  3 { f*  }           {10 9 8 6 5 4 3 1}
  4 { m OR f }        {10 9 8 5 4 1}
  5 { sn + gh }       {5}
  6 { "sn gh" }       {5}
  7 { NEAR(r a, 5) }  {9}
} {
  do_faultsim_test 4.$tn -prep {
    faultsim_restore_and_reopen
  } -body "
    execsql { SELECT rowid FROM t2 WHERE t2 MATCH '$expr' }
  " -test "
    faultsim_test_result {[list 0 $res]}
  "
}

finish_test

    if {$n != "interrupt"} {lappend DEFAULT(-faults) $n}
  }
  set DEFAULT(-prep)          ""
  set DEFAULT(-body)          ""
  set DEFAULT(-test)          ""
  set DEFAULT(-install)       ""
  set DEFAULT(-uninstall)     ""
  set DEFAULT(-start)          1
  set DEFAULT(-end)            0

  fix_testname name

  array set O [array get DEFAULT]
  array set O $args
  foreach o [array names O] {
    if {[info exists DEFAULT($o)]==0} { error "unknown option: $o" }
  }

  set faultlist [list]
  foreach f $O(-faults) {
    set flist [array names FAULTSIM $f]
    if {[llength $flist]==0} { error "unknown fault: $f" }
    set faultlist [concat $faultlist $flist]
  }

  set testspec [list -prep $O(-prep) -body $O(-body) \
      -test $O(-test) -install $O(-install) -uninstall $O(-uninstall)
      -test $O(-test) -install $O(-install) -uninstall $O(-uninstall) \
      -start $O(-start) -end $O(-end)
  ]
  foreach f [lsort -unique $faultlist] {
    eval do_one_faultsim_test "$name-$f" $FAULTSIM($f) $testspec
  }
}

#
#     -prep             Script to execute before -body.
#
#     -body             Script to execute (with fault injection).
#
#     -test             Script to execute after -body.
#
#     -start            Index of first fault to inject (default 1)
#
proc do_one_faultsim_test {testname args} {

  set DEFAULT(-injectstart)     "expr"
  set DEFAULT(-injectstop)      "expr 0"
  set DEFAULT(-injecterrlist)   [list]
  set DEFAULT(-injectinstall)   ""
  set DEFAULT(-injectuninstall) ""
  set DEFAULT(-prep)            ""
  set DEFAULT(-body)            ""
  set DEFAULT(-test)            ""
  set DEFAULT(-install)         ""
  set DEFAULT(-uninstall)       ""
  set DEFAULT(-start)           1
  set DEFAULT(-end)             0

  array set O [array get DEFAULT]
  array set O $args
  foreach o [array names O] {
    if {[info exists DEFAULT($o)]==0} { error "unknown option: $o" }
  }

  proc faultsim_test_proc {testrc testresult testnfail} $O(-test)
  proc faultsim_test_result {args} "
    uplevel faultsim_test_result_int \$args [list $O(-injecterrlist)]
  "

  eval $O(-injectinstall)
  eval $O(-install)

  set stop 0
  for {set iFail 1} {!$stop} {incr iFail} {
  for {set iFail $O(-start)}                        \
      {!$stop && ($O(-end)==0 || $iFail<=$O(-end))} \
      {incr iFail}                                  \
  {

    # Evaluate the -prep script.
    #
    eval $O(-prep)

    # Start the fault-injection. Run the -body script. Stop the fault
    # injection. Local var $nfail is set to the total number of faults