typedef struct Fts5Index Fts5Index;
typedef struct Fts5IndexIter Fts5IndexIter;

/*
** Values used as part of the flags argument passed to IndexQuery().
*/
#define FTS5INDEX_QUERY_PREFIX 0x0001       /* Prefix query */
#define FTS5INDEX_QUERY_DESC    0x0002      /* Docs in descending rowid order */

/*
** Create/destroy an Fts5Index object.
*/
int sqlite3Fts5IndexOpen(Fts5Config *pConfig, int bCreate, Fts5Index**, char**);
int sqlite3Fts5IndexClose(Fts5Index *p, int bDestroy);
................................................................................
  Fts5Index *p,                   /* FTS index to query */
  const char *pToken, int nToken, /* Token (or prefix) to query for */
  int flags,                      /* Mask of FTS5INDEX_QUERY_X flags */
  Fts5IndexIter **ppIter
);

/*
** Docid list iteration.

*/
int sqlite3Fts5IterEof(Fts5IndexIter*);
int sqlite3Fts5IterNext(Fts5IndexIter*);
int sqlite3Fts5IterNextFrom(Fts5IndexIter*, i64 iMatch);
i64 sqlite3Fts5IterRowid(Fts5IndexIter*);

/*
** Obtain the position list that corresponds to the current position.
*/
int sqlite3Fts5IterPoslist(Fts5IndexIter*, const u8 **pp, int *pn);

/*
** Close an iterator opened by sqlite3Fts5IndexQuery().
*/
void sqlite3Fts5IterClose(Fts5IndexIter*);

................................................................................
**************************************************************************/

/**************************************************************************
** Interface to code in fts5_hash.c. 
*/
typedef struct Fts5Hash Fts5Hash;

typedef struct Fts5Data Fts5Data;
struct Fts5Data {
  u8 *p;                          /* Pointer to buffer containing record */
  int n;                          /* Size of record in bytes */
  int nRef;                       /* Ref count */
};

/*
** Create a hash table, free a hash table.
*/
int sqlite3Fts5HashNew(Fts5Hash**, int *pnSize);
void sqlite3Fts5HashFree(Fts5Hash*);

int sqlite3Fts5HashWrite(
................................................................................
  int (*xEntry)(void*, i64, const u8*, int),
  int (*xTermDone)(void*)
);

int sqlite3Fts5HashQuery(
  Fts5Hash*,                      /* Hash table to query */
  const char *pTerm, int nTerm,   /* Query term */
  Fts5Data **ppData               /* OUT: Query result */













);


/*
** End of interface to code in fts5_hash.c.
**************************************************************************/

typedef struct Fts5Index Fts5Index;
typedef struct Fts5IndexIter Fts5IndexIter;

/*
** Values used as part of the flags argument passed to IndexQuery().
*/
#define FTS5INDEX_QUERY_PREFIX  0x0001      /* Prefix query */
#define FTS5INDEX_QUERY_DESC    0x0002      /* Docs in descending rowid order */

/*
** Create/destroy an Fts5Index object.
*/
int sqlite3Fts5IndexOpen(Fts5Config *pConfig, int bCreate, Fts5Index**, char**);
int sqlite3Fts5IndexClose(Fts5Index *p, int bDestroy);
................................................................................
  Fts5Index *p,                   /* FTS index to query */
  const char *pToken, int nToken, /* Token (or prefix) to query for */
  int flags,                      /* Mask of FTS5INDEX_QUERY_X flags */
  Fts5IndexIter **ppIter
);

/*
** The various operations on open token or token prefix iterators opened
** using sqlite3Fts5IndexQuery().
*/
int sqlite3Fts5IterEof(Fts5IndexIter*);
int sqlite3Fts5IterNext(Fts5IndexIter*);
int sqlite3Fts5IterNextFrom(Fts5IndexIter*, i64 iMatch);
i64 sqlite3Fts5IterRowid(Fts5IndexIter*);




int sqlite3Fts5IterPoslist(Fts5IndexIter*, const u8 **pp, int *pn);

/*
** Close an iterator opened by sqlite3Fts5IndexQuery().
*/
void sqlite3Fts5IterClose(Fts5IndexIter*);

................................................................................
**************************************************************************/

/**************************************************************************
** Interface to code in fts5_hash.c. 
*/
typedef struct Fts5Hash Fts5Hash;








/*
** Create a hash table, free a hash table.
*/
int sqlite3Fts5HashNew(Fts5Hash**, int *pnSize);
void sqlite3Fts5HashFree(Fts5Hash*);

int sqlite3Fts5HashWrite(
................................................................................
  int (*xEntry)(void*, i64, const u8*, int),
  int (*xTermDone)(void*)
);

int sqlite3Fts5HashQuery(
  Fts5Hash*,                      /* Hash table to query */
  const char *pTerm, int nTerm,   /* Query term */
  const char **ppDoclist,         /* OUT: Pointer to doclist for pTerm */
  int *pnDoclist                  /* OUT: Size of doclist in bytes */
);

void sqlite3Fts5HashScanInit(
  Fts5Hash*,                      /* Hash table to query */
  const char *pTerm, int nTerm    /* Query prefix */
);
void sqlite3Fts5HashScanNext(Fts5Hash*);
int sqlite3Fts5HashScanEof(Fts5Hash*);
void sqlite3Fts5HashScanEntry(Fts5Hash *,
  const char **pzTerm,            /* OUT: term (nul-terminated) */
  const char **ppDoclist,         /* OUT: pointer to doclist */
  int *pnDoclist                  /* OUT: size of doclist in bytes */
);


/*
** End of interface to code in fts5_hash.c.
**************************************************************************/

*/
void sqlite3Fts5BufferAppendBlob(
  int *pRc,
  Fts5Buffer *pBuf, 
  int nData, 
  const u8 *pData
){

  if( sqlite3Fts5BufferGrow(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

*/
void sqlite3Fts5BufferAppendBlob(
  int *pRc,
  Fts5Buffer *pBuf, 
  int nData, 
  const u8 *pData
){
  assert( nData>=0 );
  if( sqlite3Fts5BufferGrow(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

*/


struct Fts5Hash {
  int *pnByte;                    /* Pointer to bytes counter */
  int nEntry;                     /* Number of entries currently in hash */
  int nSlot;                      /* Size of aSlot[] array */

  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 (zKey[]) and its current data
** are stored in a single memory allocation. The position list data 
................................................................................
**   Offset of last rowid written to data area. Relative to first byte of
**   structure.
**
** nData:
**   Bytes of data written since iRowidOff.
*/
struct Fts5HashEntry {
  Fts5HashEntry *pNext;           /* Next hash entry with same hash-key */

  
  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 iCol;                       /* Column of last value written */
  int iPos;                       /* Position of last value written */
................................................................................
*/
void sqlite3Fts5HashClear(Fts5Hash *pHash){
  int i;
  for(i=0; i<pHash->nSlot; i++){
    Fts5HashEntry *pNext;
    Fts5HashEntry *pSlot;
    for(pSlot=pHash->aSlot[i]; pSlot; pSlot=pNext){
      pNext = pSlot->pNext;
      sqlite3_free(pSlot);
    }
  }
  memset(pHash->aSlot, 0, pHash->nSlot * sizeof(Fts5HashEntry*));
  pHash->nEntry = 0;
}

................................................................................
  if( !apNew ) return SQLITE_NOMEM;
  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->pNext;
      iHash = fts5HashKey(nNew, p->zKey, strlen(p->zKey));
      p->pNext = apNew[iHash];
      apNew[iHash] = p;
    }
  }

  sqlite3_free(apOld);
  pHash->nSlot = nNew;
  pHash->aSlot = apNew;
................................................................................
){
  unsigned int iHash = fts5HashKey(pHash->nSlot, pToken, nToken);
  Fts5HashEntry *p;
  u8 *pPtr;
  int nIncr = 0;                  /* Amount to increment (*pHash->pnByte) by */

  /* Attempt to locate an existing hash entry */
  for(p=pHash->aSlot[iHash]; p; p=p->pNext){
    if( memcmp(p->zKey, pToken, nToken)==0 && p->zKey[nToken]==0 ) break;
  }

  /* If an existing hash entry cannot be found, create a new one. */
  if( p==0 ){
    int nByte = sizeof(Fts5HashEntry) + nToken + 1 + 64;
    if( nByte<128 ) nByte = 128;
................................................................................
    memcpy(p->zKey, pToken, nToken);
    p->zKey[nToken] = '\0';
    p->nData = nToken + 1 + sizeof(Fts5HashEntry);
    p->nData += sqlite3PutVarint(&((u8*)p)[p->nData], iRowid);
    p->iSzPoslist = p->nData;
    p->nData += 4;
    p->iRowid = iRowid;
    p->pNext = pHash->aSlot[iHash];
    pHash->aSlot[iHash] = p;
    pHash->nEntry++;
    nIncr += p->nData;
  }

  /* Check there is enough space to append a new entry. Worst case scenario
  ** is:
................................................................................
  if( (p->nAlloc - p->nData) < (9 + 4 + 1 + 3 + 5) ){
    int nNew = p->nAlloc * 2;
    Fts5HashEntry *pNew;
    Fts5HashEntry **pp;
    pNew = (Fts5HashEntry*)sqlite3_realloc(p, nNew);
    if( pNew==0 ) return SQLITE_NOMEM;
    pNew->nAlloc = nNew;
    for(pp=&pHash->aSlot[iHash]; *pp!=p; pp=&(*pp)->pNext);
    *pp = pNew;
    p = pNew;
  }
  pPtr = (u8*)p;
  nIncr -= p->nData;

  /* If this is a new rowid, append the 4-byte size field for the previous
................................................................................
    }else{
      int i = 0;
      while( p1->zKey[i]==p2->zKey[i] ) i++;

      if( ((u8)p1->zKey[i])>((u8)p2->zKey[i]) ){
        /* p2 is smaller */
        *ppOut = p2;
        ppOut = &p2->pNext;
        p2 = p2->pNext;
      }else{
        /* p1 is smaller */
        *ppOut = p1;
        ppOut = &p1->pNext;
        p1 = p1->pNext;
      }
      *ppOut = 0;
    }
  }

  return pRet;
}
................................................................................

/*
** Extract all tokens from hash table iHash and link them into a list
** in sorted order. The hash table is cleared before returning. It is
** the responsibility of the caller to free the elements of the returned
** list.
*/
static int fts5HashEntrySort(Fts5Hash *pHash, Fts5HashEntry **ppSorted){




  const int nMergeSlot = 32;
  Fts5HashEntry **ap;
  Fts5HashEntry *pList;
  int iSlot;
  int i;

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

  for(iSlot=0; iSlot<pHash->nSlot; iSlot++){

    while( pHash->aSlot[iSlot] ){

      Fts5HashEntry *pEntry = pHash->aSlot[iSlot];
      pHash->aSlot[iSlot] = pEntry->pNext;
      pEntry->pNext = 0;
      for(i=0; ap[i]; i++){
        pEntry = fts5HashEntryMerge(pEntry, ap[i]);
        ap[i] = 0;
      }
      ap[i] = pEntry;

    }
  }

  pList = 0;
  for(i=0; i<nMergeSlot; i++){
    pList = fts5HashEntryMerge(pList, ap[i]);
  }
................................................................................
  int (*xTerm)(void*, const char*, int),
  int (*xEntry)(void*, i64, const u8*, int),
  int (*xTermDone)(void*)
){
  Fts5HashEntry *pList;
  int rc;

  rc = fts5HashEntrySort(pHash, &pList);
  if( rc==SQLITE_OK ){

    while( pList ){
      Fts5HashEntry *pNext = pList->pNext;
      if( rc==SQLITE_OK ){
        const int nSz = pList->nData - pList->iSzPoslist - 4;
        const int nKey = strlen(pList->zKey);
        i64 iRowid = 0;
        u8 *pPtr = (u8*)pList;
        int iOff = sizeof(Fts5HashEntry) + nKey + 1;

................................................................................
      }
      sqlite3_free(pList);
      pList = pNext;
    }
  }
  return rc;
}

*/


struct Fts5Hash {
  int *pnByte;                    /* Pointer to bytes counter */
  int nEntry;                     /* Number of entries currently in hash */
  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 (zKey[]) and its current data
** are stored in a single memory allocation. The position list data 
................................................................................
**   Offset of last rowid written to data area. Relative to first byte of
**   structure.
**
** nData:
**   Bytes of data written since iRowidOff.
*/
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 iCol;                       /* Column of last value written */
  int iPos;                       /* Position of last value written */
................................................................................
*/
void sqlite3Fts5HashClear(Fts5Hash *pHash){
  int i;
  for(i=0; i<pHash->nSlot; i++){
    Fts5HashEntry *pNext;
    Fts5HashEntry *pSlot;
    for(pSlot=pHash->aSlot[i]; pSlot; pSlot=pNext){
      pNext = pSlot->pHashNext;
      sqlite3_free(pSlot);
    }
  }
  memset(pHash->aSlot, 0, pHash->nSlot * sizeof(Fts5HashEntry*));
  pHash->nEntry = 0;
}

................................................................................
  if( !apNew ) return SQLITE_NOMEM;
  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, p->zKey, strlen(p->zKey));
      p->pHashNext = apNew[iHash];
      apNew[iHash] = p;
    }
  }

  sqlite3_free(apOld);
  pHash->nSlot = nNew;
  pHash->aSlot = apNew;
................................................................................
){
  unsigned int iHash = fts5HashKey(pHash->nSlot, pToken, nToken);
  Fts5HashEntry *p;
  u8 *pPtr;
  int nIncr = 0;                  /* Amount to increment (*pHash->pnByte) by */

  /* Attempt to locate an existing hash entry */
  for(p=pHash->aSlot[iHash]; p; p=p->pHashNext){
    if( memcmp(p->zKey, pToken, nToken)==0 && p->zKey[nToken]==0 ) break;
  }

  /* If an existing hash entry cannot be found, create a new one. */
  if( p==0 ){
    int nByte = sizeof(Fts5HashEntry) + nToken + 1 + 64;
    if( nByte<128 ) nByte = 128;
................................................................................
    memcpy(p->zKey, pToken, nToken);
    p->zKey[nToken] = '\0';
    p->nData = nToken + 1 + sizeof(Fts5HashEntry);
    p->nData += sqlite3PutVarint(&((u8*)p)[p->nData], iRowid);
    p->iSzPoslist = p->nData;
    p->nData += 4;
    p->iRowid = iRowid;
    p->pHashNext = pHash->aSlot[iHash];
    pHash->aSlot[iHash] = p;
    pHash->nEntry++;
    nIncr += p->nData;
  }

  /* Check there is enough space to append a new entry. Worst case scenario
  ** is:
................................................................................
  if( (p->nAlloc - p->nData) < (9 + 4 + 1 + 3 + 5) ){
    int nNew = p->nAlloc * 2;
    Fts5HashEntry *pNew;
    Fts5HashEntry **pp;
    pNew = (Fts5HashEntry*)sqlite3_realloc(p, nNew);
    if( pNew==0 ) return SQLITE_NOMEM;
    pNew->nAlloc = nNew;
    for(pp=&pHash->aSlot[iHash]; *pp!=p; pp=&(*pp)->pHashNext);
    *pp = pNew;
    p = pNew;
  }
  pPtr = (u8*)p;
  nIncr -= p->nData;

  /* If this is a new rowid, append the 4-byte size field for the previous
................................................................................
    }else{
      int i = 0;
      while( p1->zKey[i]==p2->zKey[i] ) i++;

      if( ((u8)p1->zKey[i])>((u8)p2->zKey[i]) ){
        /* p2 is smaller */
        *ppOut = p2;
        ppOut = &p2->pScanNext;
        p2 = p2->pScanNext;
      }else{
        /* p1 is smaller */
        *ppOut = p1;
        ppOut = &p1->pScanNext;
        p1 = p1->pScanNext;
      }
      *ppOut = 0;
    }
  }

  return pRet;
}
................................................................................

/*
** Extract all tokens from hash table iHash and link them into a list
** in sorted order. The hash table is cleared before returning. It is
** the responsibility of the caller to free the elements of the returned
** list.
*/
static int fts5HashEntrySort(
  Fts5Hash *pHash, 
  const char *pTerm, int nTerm,   /* Query prefix, if any */
  Fts5HashEntry **ppSorted
){
  const int nMergeSlot = 32;
  Fts5HashEntry **ap;
  Fts5HashEntry *pList;
  int iSlot;
  int i;

  *ppSorted = 0;
  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(pIter->zKey, 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;
      }
    }
  }

  pList = 0;
  for(i=0; i<nMergeSlot; i++){
    pList = fts5HashEntryMerge(pList, ap[i]);
  }
................................................................................
  int (*xTerm)(void*, const char*, int),
  int (*xEntry)(void*, i64, const u8*, int),
  int (*xTermDone)(void*)
){
  Fts5HashEntry *pList;
  int rc;

  rc = fts5HashEntrySort(pHash, 0, 0, &pList);
  if( rc==SQLITE_OK ){
    memset(pHash->aSlot, 0, sizeof(Fts5HashEntry*) * pHash->nSlot);
    while( pList ){
      Fts5HashEntry *pNext = pList->pScanNext;
      if( rc==SQLITE_OK ){
        const int nSz = pList->nData - pList->iSzPoslist - 4;
        const int nKey = strlen(pList->zKey);
        i64 iRowid = 0;
        u8 *pPtr = (u8*)pList;
        int iOff = sizeof(Fts5HashEntry) + nKey + 1;

................................................................................
      }
      sqlite3_free(pList);
      pList = pNext;
    }
  }
  return rc;
}

/*
** 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 */
  int *pnDoclist                  /* OUT: Size of doclist in bytes */
){
  unsigned int iHash = fts5HashKey(pHash->nSlot, pTerm, nTerm);
  Fts5HashEntry *p;

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

  if( p ){
    u8 *pPtr = (u8*)p;
    fts5Put4ByteVarint(&pPtr[p->iSzPoslist], p->nData - p->iSzPoslist - 4);
    *ppDoclist = &p->zKey[nTerm+1];
    *pnDoclist = p->nData - (sizeof(*p) + nTerm + 1);
  }else{
    *ppDoclist = 0;
    *pnDoclist = 0;
  }

  return SQLITE_OK;
}

void sqlite3Fts5HashScanInit(
  Fts5Hash *p,                    /* Hash table to query */
  const char *pTerm, int nTerm    /* Query prefix */
){
  fts5HashEntrySort(p, pTerm, nTerm, &p->pScan);
}

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

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

void sqlite3Fts5HashScanEntry(
  Fts5Hash *pHash,
  const char **pzTerm,            /* OUT: term (nul-terminated) */
  const char **ppDoclist,         /* OUT: pointer to doclist */
  int *pnDoclist                  /* OUT: size of doclist in bytes */
){
  Fts5HashEntry *p;
  if( (p = pHash->pScan) ){
    u8 *pPtr = (u8*)p;
    int nTerm = strlen(p->zKey);
    fts5Put4ByteVarint(&pPtr[p->iSzPoslist], p->nData - p->iSzPoslist - 4);
    *pzTerm = p->zKey;
    *ppDoclist = &p->zKey[nTerm+1];
    *pnDoclist = p->nData - (sizeof(*p) + nTerm + 1);
  }else{
    *pzTerm = 0;
    *ppDoclist = 0;
    *pnDoclist = 0;
  }
}

** without overreading if the records are corrupt.
*/
#define FTS5_DATA_ZERO_PADDING 8

typedef struct Fts5BtreeIter Fts5BtreeIter;
typedef struct Fts5BtreeIterLevel Fts5BtreeIterLevel;
typedef struct Fts5ChunkIter Fts5ChunkIter;

typedef struct Fts5DlidxIter Fts5DlidxIter;
typedef struct Fts5MultiSegIter Fts5MultiSegIter;
typedef struct Fts5NodeIter Fts5NodeIter;
typedef struct Fts5PageWriter Fts5PageWriter;
typedef struct Fts5PosIter Fts5PosIter;
typedef struct Fts5SegIter Fts5SegIter;
typedef struct Fts5DoclistIter Fts5DoclistIter;
typedef struct Fts5SegWriter Fts5SegWriter;
typedef struct Fts5Structure Fts5Structure;
typedef struct Fts5StructureLevel Fts5StructureLevel;
typedef struct Fts5StructureSegment Fts5StructureSegment;







/*
** One object per %_data table.
*/
struct Fts5Index {
  Fts5Config *pConfig;            /* Virtual table configuration */
  char *zDataTbl;                 /* Name of %_data table */
................................................................................
** Load the next leaf page into the segment iterator.
*/
static void fts5SegIterNextPage(
  Fts5Index *p,                   /* FTS5 backend object */
  Fts5SegIter *pIter              /* Iterator to advance to next page */
){
  Fts5StructureSegment *pSeg = pIter->pSeg;
  if( pIter->pLeaf ) fts5DataRelease(pIter->pLeaf);
  pIter->iLeafPgno++;
  if( pIter->iLeafPgno<=pSeg->pgnoLast ){
    pIter->pLeaf = fts5DataRead(p, 
        FTS5_SEGMENT_ROWID(pIter->iIdx, pSeg->iSegid, 0, pIter->iLeafPgno)
    );
  }else{
    pIter->pLeaf = 0;
................................................................................
            fts5SegIterNextPage(p, pIter);
            pIter->iLeafOffset = 4;
          }else if( iOff!=fts5GetU16(&a[2]) ){
            pIter->iLeafOffset += fts5GetVarint32(&a[iOff], nKeep);
          }
        }else{
          pIter->iRowid += iDelta;




















        }
      }else{
        iOff = 0;
        /* Next entry is not on the current page */
        while( iOff==0 ){
          fts5SegIterNextPage(p, pIter);
          pLeaf = pIter->pLeaf;
................................................................................
      }
      if( flags & FTS5INDEX_QUERY_DESC ){
        fts5SegIterReverse(p, iIdx, pIter);
      }
    }
  }
}





















































/*
** Zero the iterator passed as the only argument.
*/
static void fts5SegIterClear(Fts5SegIter *pIter){
  fts5BufferFree(&pIter->term);
  fts5DataRelease(pIter->pLeaf);
................................................................................
  Fts5MultiSegIter *pNew;

  assert( (pTerm==0 && nTerm==0) || iLevel<0 );

  /* Allocate space for the new multi-seg-iterator. */
  if( iLevel<0 ){
    nSeg = fts5StructureCountSegments(pStruct);

  }else{
    nSeg = MIN(pStruct->aLevel[iLevel].nSeg, nSegment);
  }
  for(nSlot=2; nSlot<nSeg; nSlot=nSlot*2);
  *ppOut = pNew = fts5IdxMalloc(p, 
      sizeof(Fts5MultiSegIter) +          /* pNew */
      sizeof(Fts5SegIter) * nSlot +       /* pNew->aSeg[] */
................................................................................
  pNew->aFirst = (u16*)&pNew->aSeg[nSlot];
  pNew->bRev = (0!=(flags & FTS5INDEX_QUERY_DESC));
  pNew->bSkipEmpty = bSkipEmpty;

  /* Initialize each of the component segment iterators. */
  if( iLevel<0 ){
    Fts5StructureLevel *pEnd = &pStruct->aLevel[pStruct->nLevel];





    for(pLvl=&pStruct->aLevel[0]; pLvl<pEnd; pLvl++){
      for(iSeg=pLvl->nSeg-1; iSeg>=0; iSeg--){
        Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
        Fts5SegIter *pIter = &pNew->aSeg[iIter++];
        if( pTerm==0 ){
          fts5SegIterInit(p, iIdx, pSeg, pIter);
        }else{
................................................................................
** the size field is at offset iOff of leaf pLeaf. 
*/
static void fts5ChunkIterInit(
  Fts5Index *p,                   /* FTS5 backend object */
  Fts5SegIter *pSeg,              /* Segment iterator to read poslist from */
  Fts5ChunkIter *pIter            /* Initialize this object */
){
  int iId = pSeg->pSeg->iSegid;
  i64 rowid = FTS5_SEGMENT_ROWID(pSeg->iIdx, iId, 0, pSeg->iLeafPgno);
  Fts5Data *pLeaf = pSeg->pLeaf;
  int iOff = pSeg->iLeafOffset;

  memset(pIter, 0, sizeof(*pIter));






  pIter->iLeafRowid = rowid;


  if( iOff<pLeaf->n ){
    fts5DataReference(pLeaf);
    pIter->pLeaf = pLeaf;
  }else{
    pIter->nRem = 1;
    fts5ChunkIterNext(p, pIter);
    if( p->rc ) return;
................................................................................
  bOldest = (pLvlOut->nSeg==1 && pStruct->nLevel==iLvl+2);

#if 0
fprintf(stdout, "merging %d segments from level %d!", nInput, iLvl);
fflush(stdout);
#endif


  for(fts5MultiIterNew(p, pStruct, iIdx, 0, 0, 0, 0, iLvl, nInput, &pIter);
      fts5MultiIterEof(p, pIter)==0;
      fts5MultiIterNext(p, pIter, 0, 0)
  ){
    Fts5SegIter *pSeg = &pIter->aSeg[ pIter->aFirst[1] ];
    Fts5ChunkIter sPos;           /* Used to iterate through position list */

** without overreading if the records are corrupt.
*/
#define FTS5_DATA_ZERO_PADDING 8

typedef struct Fts5BtreeIter Fts5BtreeIter;
typedef struct Fts5BtreeIterLevel Fts5BtreeIterLevel;
typedef struct Fts5ChunkIter Fts5ChunkIter;
typedef struct Fts5Data Fts5Data;
typedef struct Fts5DlidxIter Fts5DlidxIter;
typedef struct Fts5MultiSegIter Fts5MultiSegIter;
typedef struct Fts5NodeIter Fts5NodeIter;
typedef struct Fts5PageWriter Fts5PageWriter;
typedef struct Fts5PosIter Fts5PosIter;
typedef struct Fts5SegIter Fts5SegIter;
typedef struct Fts5DoclistIter Fts5DoclistIter;
typedef struct Fts5SegWriter Fts5SegWriter;
typedef struct Fts5Structure Fts5Structure;
typedef struct Fts5StructureLevel Fts5StructureLevel;
typedef struct Fts5StructureSegment Fts5StructureSegment;

struct Fts5Data {
  u8 *p;                          /* Pointer to buffer containing record */
  int n;                          /* Size of record in bytes */
  int nRef;                       /* Ref count */
};

/*
** One object per %_data table.
*/
struct Fts5Index {
  Fts5Config *pConfig;            /* Virtual table configuration */
  char *zDataTbl;                 /* Name of %_data table */
................................................................................
** Load the next leaf page into the segment iterator.
*/
static void fts5SegIterNextPage(
  Fts5Index *p,                   /* FTS5 backend object */
  Fts5SegIter *pIter              /* Iterator to advance to next page */
){
  Fts5StructureSegment *pSeg = pIter->pSeg;
  fts5DataRelease(pIter->pLeaf);
  pIter->iLeafPgno++;
  if( pIter->iLeafPgno<=pSeg->pgnoLast ){
    pIter->pLeaf = fts5DataRead(p, 
        FTS5_SEGMENT_ROWID(pIter->iIdx, pSeg->iSegid, 0, pIter->iLeafPgno)
    );
  }else{
    pIter->pLeaf = 0;
................................................................................
            fts5SegIterNextPage(p, pIter);
            pIter->iLeafOffset = 4;
          }else if( iOff!=fts5GetU16(&a[2]) ){
            pIter->iLeafOffset += fts5GetVarint32(&a[iOff], nKeep);
          }
        }else{
          pIter->iRowid += iDelta;
        }
      }else if( pIter->pSeg==0 ){
        const char *pList = 0;
        const char *zTerm;
        int nList;
        if( 0==(pIter->flags & FTS5_SEGITER_ONETERM) ){
          sqlite3Fts5HashScanNext(p->apHash[0]);
          sqlite3Fts5HashScanEntry(p->apHash[0], &zTerm, &pList, &nList);
        }
        if( pList==0 ){
          fts5DataRelease(pIter->pLeaf);
          pIter->pLeaf = 0;
        }else{
          pIter->pLeaf->p = (u8*)pList;
          pIter->pLeaf->n = nList;
          sqlite3Fts5BufferSet(&p->rc, &pIter->term, strlen(zTerm), (u8*)zTerm);
          pIter->iLeafOffset = getVarint((u8*)pList, (u64*)&pIter->iRowid);
          if( pIter->flags & FTS5_SEGITER_REVERSE ){
            fts5SegIterReverseInitPage(p, pIter);
          }
        }
      }else{
        iOff = 0;
        /* Next entry is not on the current page */
        while( iOff==0 ){
          fts5SegIterNextPage(p, pIter);
          pLeaf = pIter->pLeaf;
................................................................................
      }
      if( flags & FTS5INDEX_QUERY_DESC ){
        fts5SegIterReverse(p, iIdx, pIter);
      }
    }
  }
}

/*
** Initialize the object pIter to point to term pTerm/nTerm within the
** in-memory hash table iIdx. If there is no such term in the table, the 
** iterator is set to EOF.
**
** If an error occurs, Fts5Index.rc is set to an appropriate error code. If 
** an error has already occurred when this function is called, it is a no-op.
*/
static void fts5SegIterHashInit(
  Fts5Index *p,                   /* FTS5 backend */
  int iIdx,                       /* Config.aHash[] index of FTS index */
  const u8 *pTerm, int nTerm,     /* Term to seek to */
  int flags,                      /* Mask of FTS5INDEX_XXX flags */
  Fts5SegIter *pIter              /* Object to populate */
){
  Fts5Hash *pHash = p->apHash[iIdx];
  const char *pList = 0;
  int nList = 0;
  const u8 *z = 0;
  int n = 0;

  assert( pHash );

  if( pTerm==0 || (iIdx==0 && (flags & FTS5INDEX_QUERY_PREFIX)) ){
    sqlite3Fts5HashScanInit(pHash, (const char*)pTerm, nTerm);
    sqlite3Fts5HashScanEntry(pHash, (const char**)&z, &pList, &nList);
    n = (z ? strlen((const char*)z) : 0);
  }else{
    pIter->flags |= FTS5_SEGITER_ONETERM;
    sqlite3Fts5HashQuery(pHash, (const char*)pTerm, nTerm, &pList, &nList);
    z = pTerm;
    n = nTerm;
  }

  if( pList ){
    Fts5Data *pLeaf;
    sqlite3Fts5BufferSet(&p->rc, &pIter->term, n, z);
    pLeaf = fts5IdxMalloc(p, sizeof(Fts5Data));
    if( pLeaf==0 ) return;
    pLeaf->nRef = 1;
    pLeaf->p = (u8*)pList;
    pLeaf->n = nList;
    pIter->pLeaf = pLeaf;
    pIter->iLeafOffset = getVarint(pLeaf->p, (u64*)&pIter->iRowid);

    if( flags & FTS5INDEX_QUERY_DESC ){
      pIter->flags |= FTS5_SEGITER_REVERSE;
      fts5SegIterReverseInitPage(p, pIter);
    }
  }
}

/*
** Zero the iterator passed as the only argument.
*/
static void fts5SegIterClear(Fts5SegIter *pIter){
  fts5BufferFree(&pIter->term);
  fts5DataRelease(pIter->pLeaf);
................................................................................
  Fts5MultiSegIter *pNew;

  assert( (pTerm==0 && nTerm==0) || iLevel<0 );

  /* Allocate space for the new multi-seg-iterator. */
  if( iLevel<0 ){
    nSeg = fts5StructureCountSegments(pStruct);
    nSeg += (p->apHash ? 1 : 0);
  }else{
    nSeg = MIN(pStruct->aLevel[iLevel].nSeg, nSegment);
  }
  for(nSlot=2; nSlot<nSeg; nSlot=nSlot*2);
  *ppOut = pNew = fts5IdxMalloc(p, 
      sizeof(Fts5MultiSegIter) +          /* pNew */
      sizeof(Fts5SegIter) * nSlot +       /* pNew->aSeg[] */
................................................................................
  pNew->aFirst = (u16*)&pNew->aSeg[nSlot];
  pNew->bRev = (0!=(flags & FTS5INDEX_QUERY_DESC));
  pNew->bSkipEmpty = bSkipEmpty;

  /* Initialize each of the component segment iterators. */
  if( iLevel<0 ){
    Fts5StructureLevel *pEnd = &pStruct->aLevel[pStruct->nLevel];
    if( p->apHash ){
      /* Add a segment iterator for the current contents of the hash table. */
      Fts5SegIter *pIter = &pNew->aSeg[iIter++];
      fts5SegIterHashInit(p, iIdx, pTerm, nTerm, flags, pIter);
    }
    for(pLvl=&pStruct->aLevel[0]; pLvl<pEnd; pLvl++){
      for(iSeg=pLvl->nSeg-1; iSeg>=0; iSeg--){
        Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
        Fts5SegIter *pIter = &pNew->aSeg[iIter++];
        if( pTerm==0 ){
          fts5SegIterInit(p, iIdx, pSeg, pIter);
        }else{
................................................................................
** the size field is at offset iOff of leaf pLeaf. 
*/
static void fts5ChunkIterInit(
  Fts5Index *p,                   /* FTS5 backend object */
  Fts5SegIter *pSeg,              /* Segment iterator to read poslist from */
  Fts5ChunkIter *pIter            /* Initialize this object */
){


  Fts5Data *pLeaf = pSeg->pLeaf;
  int iOff = pSeg->iLeafOffset;

  memset(pIter, 0, sizeof(*pIter));
  /* If Fts5SegIter.pSeg is NULL, then this iterator iterates through data
  ** currently stored in a hash table. In this case there is no leaf-rowid
  ** to calculate.  */
  if( pSeg->pSeg ){
    int iId = pSeg->pSeg->iSegid;
    i64 rowid = FTS5_SEGMENT_ROWID(pSeg->iIdx, iId, 0, pSeg->iLeafPgno);
    pIter->iLeafRowid = rowid;
  }

  if( iOff<pLeaf->n ){
    fts5DataReference(pLeaf);
    pIter->pLeaf = pLeaf;
  }else{
    pIter->nRem = 1;
    fts5ChunkIterNext(p, pIter);
    if( p->rc ) return;
................................................................................
  bOldest = (pLvlOut->nSeg==1 && pStruct->nLevel==iLvl+2);

#if 0
fprintf(stdout, "merging %d segments from level %d!", nInput, iLvl);
fflush(stdout);
#endif

  assert( iLvl>=0 );
  for(fts5MultiIterNew(p, pStruct, iIdx, 0, 0, 0, 0, iLvl, nInput, &pIter);
      fts5MultiIterEof(p, pIter)==0;
      fts5MultiIterNext(p, pIter, 0, 0)
  ){
    Fts5SegIter *pSeg = &pIter->aSeg[ pIter->aFirst[1] ];
    Fts5ChunkIter sPos;           /* Used to iterate through position list */

do_execsql_test 6.0 {
  CREATE VIRTUAL TABLE s3 USING fts5(x);
  BEGIN;
    INSERT INTO s3 VALUES('a b c');
    INSERT INTO s3 VALUES('A B C');
}

do_execsql_test 6.1 {
  SELECT rowid FROM s3 WHERE s3 MATCH 'a'




} {2 1}

do_execsql_test 6.2 {
  COMMIT;



  SELECT rowid FROM s3 WHERE s3 MATCH 'a'
} {2 1}

finish_test

do_execsql_test 6.0 {
  CREATE VIRTUAL TABLE s3 USING fts5(x);
  BEGIN;
    INSERT INTO s3 VALUES('a b c');
    INSERT INTO s3 VALUES('A B C');
}

do_execsql_test 6.1.1 {
  SELECT rowid FROM s3 WHERE s3 MATCH 'a'
} {1 2}

do_execsql_test 6.1.2 {
  SELECT rowid FROM s3 WHERE s3 MATCH 'a' ORDER BY rowid DESC
} {2 1}

do_execsql_test 6.2 {
  COMMIT;
}

do_execsql_test 6.3 {
  SELECT rowid FROM s3 WHERE s3 MATCH 'a'
} {1 2}

finish_test

# If SQLITE_ENABLE_FTS5 is defined, omit this file.
ifcapable !fts5 {
  finish_test
  return
}

do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE xx USING fts5(x,y);
  INSERT INTO xx(xx, rank) VALUES('pgsz', 32);
}

set data {
    0   {p o q e z k z p n f y u z y n y}   {l o o l v v k}
    1   {p k h h p y l l h i p v n}         {p p l u r i f a j g e r r x w}
    2   {l s z j k i m p s}                 {l w e j t j e e i t w r o p o}
    3   {x g y m y m h p}                   {k j j b r e y y a k y}
    4   {q m a i y i z}                     {o w a g k x g j m w e u k}
    5   {k o a w y b s z}                   {s g l m m l m g p}
................................................................................
    95  {h b n j t k i h o q u}             {w n g i t o k c a m y p f l x c p}
    96  {f c x p y r b m o l m o a}         {p c a q s u n n x d c f a o}
    97  {u h h k m n k}                     {u b v n u a o c}
    98  {s p e t c z d f n w f}             {l s f j b l c e s h}
    99  {r c v w i v h a t a c v c r e}     {h h u m g o f b a e o}
}

do_test 1.1 {
  foreach {id x y} $data {
    execsql { INSERT INTO xx(rowid, x, y) VALUES($id, $x, $y) }
  }
  execsql { INSERT INTO xx(xx) VALUES('integrity-check') }
} {}

# Usage:
#
#   poslist aCol ?-pc VARNAME? ?-near N? ?-col C? -- phrase1 phrase2...
#
proc poslist {aCol args} {
  set O(-near) 10
  set O(-col)  -1
................................................................................
  set res [list]
  for {set i 0} {$i < [$cmd xInstCount]} {incr i} {
    lappend res [string map {{ } .} [$cmd xInst $i]]
  }
  set res
}







sqlite3_fts5_create_function db fts5_test_poslist fts5_test_poslist















#-------------------------------------------------------------------------
# Test phrase queries.
#
foreach {tn phrase} {
  1 "o"
  2 "b q"
  3 "e a e"
  4 "m d g q q b k b w f q q p p"
  5 "l o o l v v k"
  6 "a"
  7 "b"
  8 "c"
  9 "no"
  10 "L O O L V V K"
} {
  set expr "\"$phrase\""
  set res [matchdata 1 $expr]

  do_execsql_test 1.2.$tn.[llength $res] { 
    SELECT rowid, fts5_test_poslist(xx) FROM xx WHERE xx match $expr
  } $res
}

#-------------------------------------------------------------------------
# Test some AND and OR queries.
#
foreach {tn expr} {
  1.1 "a   AND b"
  1.2 "a+b AND c"
  1.3 "d+c AND u"
  1.4 "d+c AND u+d"

  2.1 "a   OR b"
  2.2 "a+b OR c"
  2.3 "d+c OR u"
  2.4 "d+c OR u+d"

  3.1 { a AND b AND c }
} {
  set res [matchdata 1 $expr]
  do_execsql_test 2.$tn.[llength $res] { 
    SELECT rowid, fts5_test_poslist(xx) FROM xx WHERE xx match $expr
  } $res
}

#-------------------------------------------------------------------------
# Queries on a specific column.
#
foreach {tn expr} {
  1 "x:a"
  2 "y:a"
  3 "x:b"
  4 "y:b"
} {
  set res [matchdata 1 $expr]
  do_execsql_test 3.$tn.[llength $res] { 
    SELECT rowid, fts5_test_poslist(xx) FROM xx WHERE xx match $expr
  } $res
}

#-------------------------------------------------------------------------
# Some NEAR queries.
#
foreach {tn expr} {
  1 "NEAR(a b)"
  2 "NEAR(r c)"
  2 { NEAR(r c, 5) }
  3 { NEAR(r c, 3) }
  4 { NEAR(r c, 2) }
  5 { NEAR(r c, 0) }
  6 { NEAR(a b c) }
  7 { NEAR(a b c, 8) }
  8  { x : NEAR(r c) }
  9  { y : NEAR(r c) }
} {
  set res [matchdata 1 $expr]
  do_execsql_test 4.1.$tn.[llength $res] { 
    SELECT rowid, fts5_test_poslist(xx) FROM xx WHERE xx match $expr
  } $res
}

do_test 4.1  { poslist {{a b c}} -- a } {0.0.0}
do_test 4.2  { poslist {{a b c}} -- c } {0.0.2}

foreach {tn expr tclexpr} {
  1 {a b} {[N $x -- {a}] && [N $x -- {b}]}
} {
  do_execsql_test 5.$tn {SELECT fts5_expr_tcl($expr, 'N $x')} [list $tclexpr]
}

#-------------------------------------------------------------------------
#
do_execsql_test 6.integrity {
  INSERT INTO xx(xx) VALUES('integrity-check');
}
#db eval {SELECT rowid, fts5_decode(rowid, block) aS r FROM xx_data} {puts $r}
foreach {bAsc sql} {
  1 {SELECT rowid FROM xx WHERE xx MATCH $expr}
  0 {SELECT rowid FROM xx WHERE xx MATCH $expr ORDER BY rowid DESC}
} {
  foreach {tn expr} {
    0.1 x
    1 { NEAR(r c) }
    2 { NEAR(r c, 5) }
    3 { NEAR(r c, 3) }
    4 { NEAR(r c, 2) }
    5 { NEAR(r c, 0) }
    6 { NEAR(a b c) }
    7 { NEAR(a b c, 8) }
    8  { x : NEAR(r c) }
    9  { y : NEAR(r c) }







































    10 { x : "r c" }
    11 { y : "r c" }
    12 { a AND b }
    13 { a AND b AND c }
    14a { a }
    14b { a OR b }
    15 { a OR b AND c }
    16 { c AND b OR a }
    17 { c AND (b OR a) }
    18 { c NOT (b OR a) }
    19 { c NOT b OR a AND d }
  } {
    set res [matchdata 0 $expr $bAsc]
    do_execsql_test 6.$bAsc.$tn.[llength $res] $sql $res

  }
}

finish_test

# If SQLITE_ENABLE_FTS5 is defined, omit this file.
ifcapable !fts5 {
  finish_test
  return
}






set data {
    0   {p o q e z k z p n f y u z y n y}   {l o o l v v k}
    1   {p k h h p y l l h i p v n}         {p p l u r i f a j g e r r x w}
    2   {l s z j k i m p s}                 {l w e j t j e e i t w r o p o}
    3   {x g y m y m h p}                   {k j j b r e y y a k y}
    4   {q m a i y i z}                     {o w a g k x g j m w e u k}
    5   {k o a w y b s z}                   {s g l m m l m g p}
................................................................................
    95  {h b n j t k i h o q u}             {w n g i t o k c a m y p f l x c p}
    96  {f c x p y r b m o l m o a}         {p c a q s u n n x d c f a o}
    97  {u h h k m n k}                     {u b v n u a o c}
    98  {s p e t c z d f n w f}             {l s f j b l c e s h}
    99  {r c v w i v h a t a c v c r e}     {h h u m g o f b a e o}
}








# Usage:
#
#   poslist aCol ?-pc VARNAME? ?-near N? ?-col C? -- phrase1 phrase2...
#
proc poslist {aCol args} {
  set O(-near) 10
  set O(-col)  -1
................................................................................
  set res [list]
  for {set i 0} {$i < [$cmd xInstCount]} {incr i} {
    lappend res [string map {{ } .} [$cmd xInst $i]]
  }
  set res
}


foreach {tn2 sql} {
  1  {}
  2  {BEGIN}
} {
  reset_db
  sqlite3_fts5_create_function db fts5_test_poslist fts5_test_poslist

  do_execsql_test 1.0 {
    CREATE VIRTUAL TABLE xx USING fts5(x,y);
    INSERT INTO xx(xx, rank) VALUES('pgsz', 32);
  }

  execsql $sql

  do_test $tn2.1.1 {
    foreach {id x y} $data {
      execsql { INSERT INTO xx(rowid, x, y) VALUES($id, $x, $y) }
    }
    execsql { INSERT INTO xx(xx) VALUES('integrity-check') }
  } {}

  #-------------------------------------------------------------------------
  # Test phrase queries.
  #
  foreach {tn phrase} {
    1 "o"
    2 "b q"
    3 "e a e"
    4 "m d g q q b k b w f q q p p"
    5 "l o o l v v k"
    6 "a"
    7 "b"
    8 "c"
    9 "no"
    10 "L O O L V V K"
  } {
    set expr "\"$phrase\""
    set res [matchdata 1 $expr]

    do_execsql_test $tn2.1.2.$tn.[llength $res] { 
      SELECT rowid, fts5_test_poslist(xx) FROM xx WHERE xx match $expr
    } $res
  }

  #-------------------------------------------------------------------------
  # Test some AND and OR queries.
  #
  foreach {tn expr} {
    1.1 "a   AND b"
    1.2 "a+b AND c"
    1.3 "d+c AND u"
    1.4 "d+c AND u+d"

    2.1 "a   OR b"
    2.2 "a+b OR c"
    2.3 "d+c OR u"
    2.4 "d+c OR u+d"

    3.1 { a AND b AND c }
  } {
    set res [matchdata 1 $expr]
    do_execsql_test $tn2.2.$tn.[llength $res] { 
      SELECT rowid, fts5_test_poslist(xx) FROM xx WHERE xx match $expr
    } $res
  }

  #-------------------------------------------------------------------------
  # Queries on a specific column.
  #
  foreach {tn expr} {
    1 "x:a"
    2 "y:a"
    3 "x:b"
    4 "y:b"
  } {
    set res [matchdata 1 $expr]
    do_execsql_test $tn2.3.$tn.[llength $res] { 
      SELECT rowid, fts5_test_poslist(xx) FROM xx WHERE xx match $expr
    } $res
  }

  #-------------------------------------------------------------------------
  # Some NEAR queries.
  #
  foreach {tn expr} {
    1 "NEAR(a b)"
    2 "NEAR(r c)"





































    2 { NEAR(r c, 5) }
    3 { NEAR(r c, 3) }
    4 { NEAR(r c, 2) }
    5 { NEAR(r c, 0) }
    6 { NEAR(a b c) }
    7 { NEAR(a b c, 8) }
    8  { x : NEAR(r c) }
    9  { y : NEAR(r c) }
  } {
    set res [matchdata 1 $expr]
    do_execsql_test $tn2.4.1.$tn.[llength $res] { 
      SELECT rowid, fts5_test_poslist(xx) FROM xx WHERE xx match $expr
    } $res
  }

  do_test $tn2.4.1  { poslist {{a b c}} -- a } {0.0.0}
  do_test $tn2.4.2  { poslist {{a b c}} -- c } {0.0.2}

  foreach {tn expr tclexpr} {
    1 {a b} {[N $x -- {a}] && [N $x -- {b}]}
  } {
    do_execsql_test $tn2.5.$tn {
      SELECT fts5_expr_tcl($expr, 'N $x')
    } [list $tclexpr]
  }

  #-------------------------------------------------------------------------
  #
  do_execsql_test $tn2.6.integrity {
    INSERT INTO xx(xx) VALUES('integrity-check');
  }
  #db eval {SELECT rowid, fts5_decode(rowid, block) aS r FROM xx_data} {puts $r}
  foreach {bAsc sql} {
    1 {SELECT rowid FROM xx WHERE xx MATCH $expr}
    0 {SELECT rowid FROM xx WHERE xx MATCH $expr ORDER BY rowid DESC}
  } {
    foreach {tn expr} {
      0.1 x
      1 { NEAR(r c) }
      2 { NEAR(r c, 5) }
      3 { NEAR(r c, 3) }
      4 { NEAR(r c, 2) }
      5 { NEAR(r c, 0) }
      6 { NEAR(a b c) }
      7 { NEAR(a b c, 8) }
      8  { x : NEAR(r c) }
      9  { y : NEAR(r c) }
      10 { x : "r c" }
      11 { y : "r c" }
      12 { a AND b }
      13 { a AND b AND c }
      14a { a }
      14b { a OR b }
      15 { a OR b AND c }
      16 { c AND b OR a }
      17 { c AND (b OR a) }
      18 { c NOT (b OR a) }
      19 { c NOT b OR a AND d }
    } {
      set res [matchdata 0 $expr $bAsc]
      do_execsql_test $tn2.6.$bAsc.$tn.[llength $res] $sql $res
    }
  }
}

finish_test

  }
  
  3 {
    CREATE VIRTUAL TABLE t1 USING fts5(a, b, prefix=1,2,3,4,5);
    INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
  }













} {

  do_test $T.1 { 
    execsql { DROP TABLE IF EXISTS t1 }
    execsql $create
  } {}
  
................................................................................
      }
      if {$bMatch} { lappend ret $rowid }
    }
    return $ret
  }
  
  foreach {bAsc sql} {
    1 {SELECT rowid FROM t1 WHERE t1 MATCH $prefix}
    0 {SELECT rowid FROM t1 WHERE t1 MATCH $prefix ORDER BY rowid DESC}
  } {
    foreach {tn prefix} {
      1  {a*} 2 {ab*} 3 {abc*} 4 {abcd*} 5 {abcde*} 
      6  {f*} 7 {fg*} 8 {fgh*} 9 {fghi*} 10 {fghij*}
      11 {k*} 12 {kl*} 13 {klm*} 14 {klmn*} 15 {klmno*}
      16 {p*} 17 {pq*} 18 {pqr*} 19 {pqrs*} 20 {pqrst*}
      21 {u*} 22 {uv*} 23 {uvw*} 24 {uvwx*} 25 {uvwxy*} 26 {uvwxyz*}
................................................................................
      28 {a f*} 29 {a* f*} 30 {a* fghij*}
    } {
      set res [prefix_query $prefix]
      if {$bAsc} {
        set res [lsort -integer -increasing $res]
      }
      set n [llength $res]

      do_execsql_test $T.$bAsc.$tn.$n $sql $res
    }
  }


}

finish_test

  }
  
  3 {
    CREATE VIRTUAL TABLE t1 USING fts5(a, b, prefix=1,2,3,4,5);
    INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
  }

  4 {
    CREATE VIRTUAL TABLE t1 USING fts5(a, b);
    INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
    BEGIN;
  }
  
  5 {
    CREATE VIRTUAL TABLE t1 USING fts5(a, b, prefix=1,2,3,4,5);
    INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
    BEGIN;
  }

} {

  do_test $T.1 { 
    execsql { DROP TABLE IF EXISTS t1 }
    execsql $create
  } {}
  
................................................................................
      }
      if {$bMatch} { lappend ret $rowid }
    }
    return $ret
  }
  
  foreach {bAsc sql} {
    0 {SELECT rowid FROM t1 WHERE t1 MATCH $prefix ORDER BY rowid DESC}
    1 {SELECT rowid FROM t1 WHERE t1 MATCH $prefix}
  } {
    foreach {tn prefix} {
      1  {a*} 2 {ab*} 3 {abc*} 4 {abcd*} 5 {abcde*} 
      6  {f*} 7 {fg*} 8 {fgh*} 9 {fghi*} 10 {fghij*}
      11 {k*} 12 {kl*} 13 {klm*} 14 {klmn*} 15 {klmno*}
      16 {p*} 17 {pq*} 18 {pqr*} 19 {pqrs*} 20 {pqrst*}
      21 {u*} 22 {uv*} 23 {uvw*} 24 {uvwx*} 25 {uvwxy*} 26 {uvwxyz*}
................................................................................
      28 {a f*} 29 {a* f*} 30 {a* fghij*}
    } {
      set res [prefix_query $prefix]
      if {$bAsc} {
        set res [lsort -integer -increasing $res]
      }
      set n [llength $res]
      if {$T==5} breakpoint 
      do_execsql_test $T.$bAsc.$tn.$n $sql $res
    }
  }

  catchsql COMMIT
}

finish_test