SQLite

void sqlite3Fts5BufferAppendBlob(
  int *pRc,
  Fts5Buffer *pBuf, 
  u32 nData, 
  const u8 *pData
){
  assert_nc( *pRc || nData>=0 );
  if( nData ){
    if( fts5BufferGrow(pRc, pBuf, nData) ) return;
    memcpy(&pBuf->p[pBuf->n], pData, nData);
    pBuf->n += nData;
  }
}

/*
** Append the nul-terminated string zStr to the buffer pBuf. This function
** ensures that the byte following the buffer data is set to 0x00, even 
** though this byte is not included in the pBuf->n count.
*/

  return SQLITE_OK;
}

void *sqlite3Fts5MallocZero(int *pRc, int nByte){
  void *pRet = 0;
  if( *pRc==SQLITE_OK ){
    pRet = sqlite3_malloc(nByte);
    if( pRet==0 ){
      if( nByte>0 ) *pRc = SQLITE_NOMEM;
    }else{
      memset(pRet, 0, nByte);
    }
  }
  return pRet;
}

  int nSlot;                      /* Size of aSlot[] array */
  Fts5HashEntry *pScan;           /* Current ordered scan item */
  Fts5HashEntry **aSlot;          /* Array of hash slots */
};

/*
** Each entry in the hash table is represented by an object of the 
** following type. Each object, its key (a nul-terminated string) and 
** its current data are stored in a single memory allocation. The 
** key immediately follows the object in memory. The position list
** data immediately follows the key data in memory.
**
** The data that follows the key is in a similar, but not identical format
** to the doclist data stored in the database. It is:
**
**   * Rowid, as a varint
**   * Position list, without 0x00 terminator.
**   * Size of previous position list and rowid, as a 4 byte

struct Fts5HashEntry {
  Fts5HashEntry *pHashNext;       /* Next hash entry with same hash-key */
  Fts5HashEntry *pScanNext;       /* Next entry in sorted order */
  
  int nAlloc;                     /* Total size of allocation */
  int iSzPoslist;                 /* Offset of space for 4-byte poslist size */
  int nData;                      /* Total bytes of data (incl. structure) */
  int nKey;                       /* Length of key in bytes */
  u8 bDel;                        /* Set delete-flag @ iSzPoslist */
  u8 bContent;                    /* Set content-flag (detail=none mode) */
  i16 iCol;                       /* Column of last value written */
  int iPos;                       /* Position of last value written */
  i64 iRowid;                     /* Rowid of last value written */

};

/*
** Eqivalent to:
**
**   char *fts5EntryKey(Fts5HashEntry *pEntry){ return zKey; }
*/

#define fts5EntryKey(p) ( ((char *)(&(p)[1])) )


/*
** Allocate a new hash table.
*/
int sqlite3Fts5HashNew(Fts5Config *pConfig, Fts5Hash **ppNew, int *pnByte){
  int rc = SQLITE_OK;

  memset(apNew, 0, nNew*sizeof(Fts5HashEntry*));

  for(i=0; i<pHash->nSlot; i++){
    while( apOld[i] ){
      int iHash;
      Fts5HashEntry *p = apOld[i];
      apOld[i] = p->pHashNext;
      iHash = fts5HashKey(nNew, (u8*)fts5EntryKey(p), strlen(fts5EntryKey(p)));
      p->pHashNext = apNew[iHash];
      apNew[iHash] = p;
    }
  }

  sqlite3_free(apOld);
  pHash->nSlot = nNew;

  int bNew;                       /* If non-delete entry should be written */
  
  bNew = (pHash->eDetail==FTS5_DETAIL_FULL);

  /* Attempt to locate an existing hash entry */
  iHash = fts5HashKey2(pHash->nSlot, (u8)bByte, (const u8*)pToken, nToken);
  for(p=pHash->aSlot[iHash]; p; p=p->pHashNext){
    char *zKey = fts5EntryKey(p);
    if( zKey[0]==bByte 
     && p->nKey==nToken
     && memcmp(&zKey[1], pToken, nToken)==0 
    ){
      break;
    }
  }

  /* If an existing hash entry cannot be found, create a new one. */
  if( p==0 ){
    /* Figure out how much space to allocate */
    char *zKey;
    int nByte = sizeof(Fts5HashEntry) + (nToken+1) + 1 + 64;
    if( nByte<128 ) nByte = 128;

    /* Grow the Fts5Hash.aSlot[] array if necessary. */
    if( (pHash->nEntry*2)>=pHash->nSlot ){
      int rc = fts5HashResize(pHash);
      if( rc!=SQLITE_OK ) return rc;
      iHash = fts5HashKey2(pHash->nSlot, (u8)bByte, (const u8*)pToken, nToken);
    }

    /* Allocate new Fts5HashEntry and add it to the hash table. */
    p = (Fts5HashEntry*)sqlite3_malloc(nByte);
    if( !p ) return SQLITE_NOMEM;
    memset(p, 0, sizeof(Fts5HashEntry));
    p->nAlloc = nByte;
    zKey = fts5EntryKey(p);
    zKey[0] = bByte;
    memcpy(&zKey[1], pToken, nToken);
    assert( iHash==fts5HashKey(pHash->nSlot, (u8*)zKey, nToken+1) );
    p->nKey = nToken;
    zKey[nToken+1] = '\0';
    p->nData = nToken+1 + 1 + sizeof(Fts5HashEntry);
    p->pHashNext = pHash->aSlot[iHash];
    pHash->aSlot[iHash] = p;
    pHash->nEntry++;

    /* Add the first rowid field to the hash-entry */
    p->nData += sqlite3Fts5PutVarint(&((u8*)p)[p->nData], iRowid);
    p->iRowid = iRowid;

      *ppOut = p2;
      p2 = 0;
    }else if( p2==0 ){
      *ppOut = p1;
      p1 = 0;
    }else{
      int i = 0;
      char *zKey1 = fts5EntryKey(p1);
      char *zKey2 = fts5EntryKey(p2);
      while( zKey1[i]==zKey2[i] ) i++;

      if( ((u8)zKey1[i])>((u8)zKey2[i]) ){
        /* p2 is smaller */
        *ppOut = p2;
        ppOut = &p2->pScanNext;
        p2 = p2->pScanNext;
      }else{
        /* p1 is smaller */
        *ppOut = p1;

  ap = sqlite3_malloc(sizeof(Fts5HashEntry*) * nMergeSlot);
  if( !ap ) return SQLITE_NOMEM;
  memset(ap, 0, sizeof(Fts5HashEntry*) * nMergeSlot);

  for(iSlot=0; iSlot<pHash->nSlot; iSlot++){
    Fts5HashEntry *pIter;
    for(pIter=pHash->aSlot[iSlot]; pIter; pIter=pIter->pHashNext){
      if( pTerm==0 || 0==memcmp(fts5EntryKey(pIter), pTerm, nTerm) ){
        Fts5HashEntry *pEntry = pIter;
        pEntry->pScanNext = 0;
        for(i=0; ap[i]; i++){
          pEntry = fts5HashEntryMerge(pEntry, ap[i]);
          ap[i] = 0;
        }
        ap[i] = pEntry;

int sqlite3Fts5HashQuery(
  Fts5Hash *pHash,                /* Hash table to query */
  const char *pTerm, int nTerm,   /* Query term */
  const u8 **ppDoclist,           /* OUT: Pointer to doclist for pTerm */
  int *pnDoclist                  /* OUT: Size of doclist in bytes */
){
  unsigned int iHash = fts5HashKey(pHash->nSlot, (const u8*)pTerm, nTerm);
  char *zKey;
  Fts5HashEntry *p;

  for(p=pHash->aSlot[iHash]; p; p=p->pHashNext){
    zKey = fts5EntryKey(p);
    if( memcmp(zKey, pTerm, nTerm)==0 && zKey[nTerm]==0 ) break;
  }

  if( p ){
    fts5HashAddPoslistSize(pHash, p);
    *ppDoclist = (const u8*)&zKey[nTerm+1];
    *pnDoclist = p->nData - (sizeof(Fts5HashEntry) + nTerm + 1);
  }else{
    *ppDoclist = 0;
    *pnDoclist = 0;
  }

  return SQLITE_OK;
}

  Fts5Hash *pHash,
  const char **pzTerm,            /* OUT: term (nul-terminated) */
  const u8 **ppDoclist,           /* OUT: pointer to doclist */
  int *pnDoclist                  /* OUT: size of doclist in bytes */
){
  Fts5HashEntry *p;
  if( (p = pHash->pScan) ){
    char *zKey = fts5EntryKey(p);
    int nTerm = (int)strlen(zKey);
    fts5HashAddPoslistSize(pHash, p);
    *pzTerm = zKey;
    *ppDoclist = (const u8*)&zKey[nTerm+1];
    *pnDoclist = p->nData - (sizeof(Fts5HashEntry) + nTerm + 1);
  }else{
    *pzTerm = 0;
    *ppDoclist = 0;
    *pnDoclist = 0;
  }
}

    }
    fts5MultiIterFree(p1);

    pData = fts5IdxMalloc(p, sizeof(Fts5Data) + doclist.n);
    if( pData ){
      pData->p = (u8*)&pData[1];
      pData->nn = pData->szLeaf = doclist.n;
      if( doclist.n ) memcpy(pData->p, doclist.p, doclist.n);
      fts5MultiIterNew2(p, pData, bDesc, ppIter);
    }
    fts5BufferFree(&doclist);
  }

  fts5StructureRelease(pStruct);
  sqlite3_free(aBuf);

  Fts5Buffer buf = {0, 0, 0};

  /* If the QUERY_SCAN flag is set, all other flags must be clear. */
  assert( (flags & FTS5INDEX_QUERY_SCAN)==0 || flags==FTS5INDEX_QUERY_SCAN );

  if( sqlite3Fts5BufferSize(&p->rc, &buf, nToken+1)==0 ){
    int iIdx = 0;                 /* Index to search */
    if( nToken ) memcpy(&buf.p[1], pToken, nToken);

    /* Figure out which index to search and set iIdx accordingly. If this
    ** is a prefix query for which there is no prefix index, set iIdx to
    ** greater than pConfig->nPrefix to indicate that the query will be
    ** satisfied by scanning multiple terms in the main index.
    **
    ** If the QUERY_TEST_NOIDX flag was specified, then this must be a

      if( p->rc==SQLITE_OK ){
        Fts5SegIter *pSeg = &pRet->aSeg[pRet->aFirst[1].iFirst];
        if( pSeg->pLeaf ) pRet->xSetOutputs(pRet, pSeg);
      }
    }

    if( p->rc ){
      sqlite3Fts5IterClose((Fts5IndexIter*)pRet);
      pRet = 0;
      fts5CloseReader(p);
    }

    *ppIter = &pRet->base;
    sqlite3Fts5BufferFree(&buf);
  }