SQLite

  pHash->nEntry = 0;
  sqlite3_free(ap);
  *ppSorted = pList;
  return SQLITE_OK;
}


















































/*
** Query the hash table for a doclist associated with term pTerm/nTerm.
*/
int sqlite3Fts5HashQuery(
  Fts5Hash *pHash,                /* Hash table to query */
  const char *pTerm, int nTerm,   /* Query term */
  const char **ppDoclist,         /* OUT: Pointer to doclist for pTerm */

  Fts5Hash *p,                    /* Hash table to query */
  const char *pTerm, int nTerm    /* Query prefix */
){
  fts5HashEntrySort(p, pTerm, nTerm, &p->pScan);
}

void sqlite3Fts5HashScanNext(Fts5Hash *p){
  Fts5HashEntry *pScan = p->pScan;
  if( pScan ) p->pScan = pScan->pScanNext;

}

int sqlite3Fts5HashScanEof(Fts5Hash *p){
  return (p->pScan==0);
}

void sqlite3Fts5HashScanEntry(

**
**     doclist format:
**
**         varint:  first rowid
**         poslist: first poslist
**         zero-or-more {
**           varint:  rowid delta (always > 0)
**           poslist: next poslist
**         }
**         0x00 byte
**
**     poslist format:
**
**         varint: size of poslist in bytes. not including this field.
**         collist: collist for column 0

** term, write it now.
*/
static void fts5WriteBtreeNEmpty(Fts5Index *p, Fts5SegWriter *pWriter){
  if( pWriter->nEmpty ){
    int bFlag = 0;
    Fts5PageWriter *pPg;
    pPg = &pWriter->aWriter[1];
    if( pWriter->nEmpty>=FTS5_MIN_DLIDX_SIZE && pWriter->cdlidx.n ){
      i64 iKey = FTS5_DOCLIST_IDX_ROWID(
          pWriter->iIdx, pWriter->iSegid, 
          pWriter->aWriter[0].pgno - 1 - pWriter->nEmpty
      );
      assert( pWriter->cdlidx.n>0 );
      fts5DataWrite(p, iKey, pWriter->cdlidx.p, pWriter->cdlidx.n);
      bFlag = 1;

  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 ){
    Fts5PageWriter *pLeaf = &pWriter->aWriter[0];
    if( pLeaf->pgno==1 && pLeaf->buf.n==0 ){
      *pnLeaf = 0;
      *pnHeight = 0;
    }else{
      if( pLeaf->buf.n>4 ){
        fts5WriteFlushLeaf(p, pWriter);
      }
      *pnLeaf = pLeaf->pgno-1;
      if( pWriter->nWriter==1 && pWriter->nEmpty>=FTS5_MIN_DLIDX_SIZE ){
        fts5WriteBtreeGrow(p, pWriter);
      }
      if( pWriter->nWriter>1 ){
        fts5WriteBtreeNEmpty(p, pWriter);
      }
      *pnHeight = pWriter->nWriter;

typedef struct Fts5FlushCtx Fts5FlushCtx;
struct Fts5FlushCtx {
  Fts5Index *pIdx;
  Fts5SegWriter writer; 
};







/*



** Buffer aBuf[] contains a list of varints, all small enough to fit

** in a 32-bit integer. Return the size of the largest prefix of this 

** list nMax bytes or less in size.
*/
static int fts5PoslistPrefix(const u8 *aBuf, int nMax){



  int ret = 0;
  while( 1 ){


    u32 dummy;




    int i = fts5GetVarint32(&aBuf[ret], dummy);

    if( (ret + i) > nMax ) break;
    ret += i;


  }


  return ret;
}

/*
** 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 
** already occurred, this function is a no-op.
*/
static void fts5FlushOneHash(Fts5Index *p, int iHash, int *pnLeaf){
  Fts5Hash *pHash = p->apHash[iHash];
  Fts5Structure *pStruct;
  int iSegid;
  int pgnoLast = 0;                 /* Last leaf page number in segment */

  /* Obtain a reference to the index structure and allocate a new segment-id
  ** for the new level-0 segment.  */
  pStruct = fts5StructureRead(p, iHash);
  iSegid = fts5AllocateSegid(p, pStruct);

  if( iSegid ){
    const int pgsz = p->pConfig->pgsz;

    Fts5StructureSegment *pSeg;   /* New segment within pStruct */
    int nHeight;                  /* Height of new segment b-tree */
    Fts5Buffer *pBuf;             /* Buffer in which to assemble leaf page */

    Fts5SegWriter writer;
    fts5WriteInit(p, &writer, iHash, iSegid);

    /* Pre-allocate the buffer used to assemble leaf pages to the target
    ** page size.  */
    assert( pgsz>0 );
    pBuf = &writer.aWriter[0].buf;
    fts5BufferGrow(&p->rc, pBuf, pgsz + 20);

    /* Begin scanning through hash table entries. */
    if( p->rc==SQLITE_OK ){
      memset(pBuf->p, 0, 4);
      pBuf->n = 4;
      sqlite3Fts5HashScanInit(pHash, 0, 0);
    }

    while( 0==sqlite3Fts5HashScanEof(pHash) ){
      const char *zTerm;
      int nTerm;
      const u8 *pDoclist;
      int nDoclist;

      sqlite3Fts5HashScanEntry(pHash, &zTerm,(const char**)&pDoclist,&nDoclist);
      nTerm = strlen(zTerm);

      /* Decide if the term fits on the current leaf. If not, flush it
      ** to disk.  */
      if( (pBuf->n + nTerm + 2) > pgsz ){
        fts5WriteFlushLeaf(p, &writer);
        pBuf = &writer.aWriter[0].buf;
        if( (nTerm + 32) > pBuf->nSpace ){
          fts5BufferGrow(&p->rc, pBuf, nTerm + 32 - pBuf->n);
        }
      }

      /* Write the term to the leaf. And push it up into the b-tree hierarchy */
      if( writer.bFirstTermInPage==0 ){
        pBuf->n += sqlite3PutVarint(&pBuf->p[pBuf->n], 0);
      }else{
        fts5PutU16(&pBuf->p[2], pBuf->n);
        writer.bFirstTermInPage = 0;
        if( writer.aWriter[0].pgno!=1 ){
          fts5WriteBtreeTerm(p, &writer, nTerm, (const u8*)zTerm);
          pBuf = &writer.aWriter[0].buf;
        }
      }
      pBuf->n += sqlite3PutVarint(&pBuf->p[pBuf->n], nTerm);
      fts5BufferAppendBlob(&p->rc, pBuf, nTerm, (const u8*)zTerm);

      if( pgsz>=(pBuf->n + nDoclist + 1) ){
        /* The entire doclist will fit on the current leaf. */
        fts5BufferAppendBlob(&p->rc, pBuf, nDoclist, pDoclist);
      }else{
        i64 iRowid = 0;
        i64 iDelta = 0;
        int iOff = 0;
        int bFirstDocid = 0;

        /* The entire doclist will not fit on this leaf. The following 
        ** loop iterates through the poslists that make up the current 
        ** doclist.  */
        while( iOff<nDoclist ){
          u32 nPos;
          int nCopy;
          iOff += getVarint(&pDoclist[iOff], (u64*)&iDelta);
          nCopy = fts5GetVarint32(&pDoclist[iOff], nPos);
          nCopy += nPos;
          iRowid += iDelta;
          
          if( bFirstDocid ){
            fts5PutU16(&pBuf->p[0], pBuf->n);   /* first docid on page */
            pBuf->n += sqlite3PutVarint(&pBuf->p[pBuf->n], iRowid);
            bFirstDocid = 0;
          }else{
            pBuf->n += sqlite3PutVarint(&pBuf->p[pBuf->n], iDelta);
          }
          assert( pBuf->n<=pBuf->nSpace );

          if( (pBuf->n + nCopy) <= pgsz ){
            /* The entire poslist will fit on the current leaf. So copy
            ** it in one go. */
            fts5BufferAppendBlob(&p->rc, pBuf, nCopy, &pDoclist[iOff]);
          }else{
            /* The entire poslist will not fit on this leaf. So it needs
            ** to be broken into sections. The only qualification being
            ** that each varint must be stored contiguously.  */
            const u8 *pPoslist = &pDoclist[iOff];
            int iPos = 0;
            while( 1 ){
              int nSpace = pgsz - pBuf->n;
              int n;
              if( (nCopy - iPos)<=nSpace ){
                n = nCopy - iPos;
              }else{
                n = fts5PoslistPrefix(&pPoslist[iPos], nSpace);
              }
              fts5BufferAppendBlob(&p->rc, pBuf, n, &pPoslist[iPos]);
              iPos += n;
              if( iPos>=nCopy ) break;
              fts5WriteFlushLeaf(p, &writer);
              pBuf = &writer.aWriter[0].buf;
            }
            bFirstDocid = 1;
          }
          assert( pBuf->n<=pgsz );
          iOff += nCopy;
        }
      }

      pBuf->p[pBuf->n++] = '\0';
      assert( pBuf->n<=pBuf->nSpace );
      sqlite3Fts5HashScanNext(pHash);
    }
    sqlite3Fts5HashClear(pHash);
    fts5WriteFinish(p, &writer, &nHeight, &pgnoLast);

    /* Update the Fts5Structure. It is written back to the database by the
    ** fts5StructureRelease() call below.  */
    if( pStruct->nLevel==0 ){
      fts5StructureAddLevel(&p->rc, &pStruct);
    }
    fts5StructureExtendLevel(&p->rc, pStruct, 0, 1, 0);