SQLite

  set res "<dl>\n"
  foreach line [split [string trim $docs] "\n"] {
    regexp {[*][*](.*)} $line -> line
    if {[regexp {^ ?x.*:} $line]} {
      append res "<dt><b>$line</b></dt><dd><p style=margin-top:0>\n"
      continue
    }
    if {[regexp {SYNONYM SUPPORT} $line]} {
      set line "</dl><h3>Synonym Support</h3>"
    }
    if {[string trim $line] == ""} {
      append res "<p>\n"
    } else {
      append res "$line\n"
    }
  }


  set res
}

proc get_api_docs {data} {
  # Initialize global array M as a map from Fts5StructureApi member name
  # to member definition. i.e.

  switch $::extract_api_docs_mode {
    fts5_api {
      output [get_fts5_struct $data "typedef struct fts5_api" "^\};"]
    }

    fts5_tokenizer {
      output [get_fts5_struct $data "typedef struct Fts5Tokenizer" "^\};"]
      output [get_fts5_struct $data \
        "Flags that may be passed as the third argument to xTokenize()" \
        "#define FTS5_TOKEN_COLOCATED"
      ]
    }

    fts5_extension {
      output [get_fts5_struct $data "typedef.*Fts5ExtensionApi" "^.;"]
    }

    Fts5ExtensionApi {

  int (*xColumnCount)(Fts5Context*);
  int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
  int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);

  int (*xTokenize)(Fts5Context*, 
    const char *pText, int nText, /* Text to tokenize */
    void *pCtx,                   /* Context passed to xToken() */
    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
  );

  int (*xPhraseCount)(Fts5Context*);
  int (*xPhraseSize)(Fts5Context*, int iPhrase);

  int (*xInstCount)(Fts5Context*, int *pnInst);
  int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);

** xDelete:
**   This function is invoked to delete a tokenizer handle previously
**   allocated using xCreate(). Fts5 guarantees that this function will
**   be invoked exactly once for each successful call to xCreate().
**
** xTokenize:
**   This function is expected to tokenize the nText byte string indicated 
**   by argument pText. pText may or may not be nul-terminated. The first
**   argument passed to this function is a pointer to an Fts5Tokenizer object
**   returned by an earlier call to xCreate().
**
**   The second argument indicates the reason that FTS5 is requesting
**   tokenization of the supplied text. This is always one of the following
**   four values:
**
**   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
**            or removed from the FTS table. The tokenizer is being invoked to
**            determine the set of tokens to add to (or delete from) the
**            FTS index.
**
**       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed 
**            against the FTS index. The tokenizer is being called to tokenize 
**            a bareword or quoted string specified as part of the query.
**
**       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
**            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
**            followed by a "*" character, indicating that the last token
**            returned by the tokenizer will be treated as a token prefix.
**
**       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to 
**            satisfy an fts5_api.xTokenize() request made by an auxiliary
**            function. Or an fts5_api.xColumnSize() request made by the same
**            on a columnsize=0 database.  
**   </ul>
**
**   For each token in the input string, the supplied callback xToken() must
**   be invoked. The first argument to it should be a copy of the pointer
**   passed as the second argument to xTokenize(). The third and fourth
**   arguments are a pointer to a buffer containing the token text, and the
**   size of the token in bytes. The 4th and 5th arguments are the byte offsets
**   of the first byte of and first byte immediately following the text from
**   which the token is derived within the input.
**
**   The second argument passed to the xToken() callback ("tflags") should
**   normally be set to 0. The exception is if the tokenizer supports 
**   synonyms. In this case see the discussion below for details.
**
**   FTS5 assumes the xToken() callback is invoked for each token in the 
**   order that they occur within the input text.
**
**   If an xToken() callback returns any value other than SQLITE_OK, then
**   the tokenization should be abandoned and the xTokenize() method should
**   immediately return a copy of the xToken() return value. Or, if the
**   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
**   if an error occurs with the xTokenize() implementation itself, it
**   may abandon the tokenization and return any error code other than
**   SQLITE_OK or SQLITE_DONE.
**
** SYNONYM SUPPORT
**
**   Custom tokenizers may also support synonyms. Consider a case in which a
**   user wishes to query for a phrase such as "first place". Using the 
**   built-in tokenizers, the FTS5 query 'first + place' will match instances
**   of "first place" within the document set, but not alternative forms
**   such as "1st place". In some applications, it would be better to match
**   all instances of "first place" or "1st place" regardless of which form
**   the user specified in the MATCH query text.
**
**   There are several ways to approach this in FTS5:
**
**   <ol><li> By mapping all synonyms to a single token. In this case, the 
**            In the above example, this means that the tokenizer returns the
**            same token for inputs "first" and "1st". Say that token is in
**            fact "first", so that when the user inserts the document "I won
**            1st place" entries are added to the index for tokens "i", "won",
**            "first" and "place". If the user then queries for '1st + place',
**            the tokenizer substitutes "first" for "1st" and the query works
**            as expected.
**
**       <li> By adding multiple synonyms for a single term to the FTS index.
**            In this case, when tokenizing query text, the tokenizer may 
**            provide multiple synonyms for a single term within the document.
**            FTS5 then queries the index for each synonym individually. For
**            example, faced with the query:
**
**   <codeblock>
**     ... MATCH 'first place'</codeblock>
**
**            the tokenizer offers both "1st" and "first" as synonyms for the
**            first token in the MATCH query and FTS5 effectively runs a query 
**            similar to:
**
**   <codeblock>
**     ... MATCH '(first OR 1st) place'</codeblock>
**
**            except that, for the purposes of auxiliary functions, the query
**            still appears to contain just two phrases - "(first OR 1st)" 
**            being treated as a single phrase.
**
**       <li> By adding multiple synonyms for a single term to the FTS index.
**            Using this method, when tokenizing document text, the tokenizer
**            provides multiple synonyms for each token. So that when a 
**            document such as "I won first place" is tokenized, entries are
**            added to the FTS index for "i", "won", "first", "1st" and
**            "place".
**
**            This way, even if the tokenizer does not provide synonyms
**            when tokenizing query text (it should not - to do would be
**            inefficient), it doesn't matter if the user queries for 
**            'first + place' or '1st + place', as there are entires in the
**            FTS index corresponding to both forms of the first token.
**   </ol>
**
**   Whether is is parsing document or query text, any call to xToken that
**   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
**   is considered to supply a synonym for the previous token. For example,
**   when parsing the document "I won first place", a tokenizer that supports
**   synonyms would call xToken() 5 times, as follows:
**
**   <codeblock>
**       xToken(pCtx, 0, "i",                      1,  0,  1);
**       xToken(pCtx, 0, "won",                    3,  2,  5);
**       xToken(pCtx, 0, "first",                  5,  6, 11);
**       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
**       xToken(pCtx, 0, "place",                  5, 12, 17);
**</codeblock>
**
**   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
**   xToken() is called. Multiple synonyms may be specified for a single token
**   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence. 
**   There is no limit to the number of synonyms that may be provided for a
**   single token.
**
**   In many cases, method (1) above is the best approach. It does not add 
**   extra data to the FTS index or require FTS5 to query for multiple terms,
**   so it is efficient in terms of disk space and query speed. However, it
**   does not support prefix queries very well. If, as suggested above, the
**   token "first" is subsituted for "1st" by the tokenizer, then the query:
**
**   <codeblock>
**     ... MATCH '1s*'</codeblock>
**
**   will not match documents that contain the token "1st" (as the tokenizer
**   will probably not map "1s" to any prefix of "first").
**
**   For full prefix support, method (3) may be preferred. In this case, 
**   because the index contains entries for both "first" and "1st", prefix
**   queries such as 'fi*' or '1s*' will match correctly. However, because
**   extra entries are added to the FTS index, this method uses more space
**   within the database.
**
**   Method (2) offers a midpoint between (1) and (3). Using this method,
**   a query such as '1s*' will match documents that contain the literal 
**   token "1st", but not "first" (assuming the tokenizer is not able to
**   provide synonyms for prefixes). However, a non-prefix query like '1st'
**   will match against "1st" and "first". This method does not require
**   extra disk space, as no extra entries are added to the FTS index. 
**   On the other hand, it may require more CPU cycles to run MATCH queries,
**   as separate queries of the FTS index are required for each synonym.
**
**   When using methods (2) or (3), it is important that the tokenizer only
**   provide synonyms when tokenizing document text (method (2)) or query
**   text (method (3)), not both. Doing so will not cause any errors, but is
**   inefficient.
*/
typedef struct Fts5Tokenizer Fts5Tokenizer;
typedef struct fts5_tokenizer fts5_tokenizer;
struct fts5_tokenizer {
  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
  void (*xDelete)(Fts5Tokenizer*);
  int (*xTokenize)(Fts5Tokenizer*, 
      void *pCtx,
      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
      const char *pText, int nText, 
      int (*xToken)(
        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
        int tflags,         /* Mask of FTS5_TOKEN_* flags */
        const char *pToken, /* Pointer to buffer containing token */
        int nToken,         /* Size of token in bytes */
        int iStart,         /* Byte offset of token within input text */
        int iEnd            /* Byte offset of end of token within input text */
      )
  );
};

/* Flags that may be passed as the third argument to xTokenize() */
#define FTS5_TOKENIZE_QUERY     0x0001
#define FTS5_TOKENIZE_PREFIX    0x0002
#define FTS5_TOKENIZE_DOCUMENT  0x0004
#define FTS5_TOKENIZE_AUX       0x0008

/* Flags that may be passed by the tokenizer implementation back to FTS5
** as the third argument to the supplied xToken callback. */
#define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */

/*
** END OF CUSTOM TOKENIZERS
*************************************************************************/

/*************************************************************************
** FTS5 EXTENSION REGISTRATION API
*/
typedef struct fts5_api fts5_api;
struct fts5_api {
  int iVersion;                   /* Currently always set to 2 */

  /* Create a new tokenizer */
  int (*xCreateTokenizer)(
    fts5_api *pApi,
    const char *zName,
    void *pContext,
    fts5_tokenizer *pTokenizer,

**   This exists in order to allow the fts5_index.c module to return a 
**   decent error message if it encounters a file-format version it does
**   not understand.
**
** bColumnsize:
**   True if the %_docsize table is created.
**
** bPrefixIndex:
**   This is only used for debugging. If set to false, any prefix indexes
**   are ignored. This value is configured using:
**
**       INSERT INTO tbl(tbl, rank) VALUES('prefix-index', $bPrefixIndex);
**
*/
struct Fts5Config {
  sqlite3 *db;                    /* Database handle */
  char *zDb;                      /* Database holding FTS index (e.g. "main") */
  char *zName;                    /* Name of FTS index */
  int nCol;                       /* Number of columns */
  char **azCol;                   /* Column names */

  int nAutomerge;                 /* 'automerge' setting */
  int nCrisisMerge;               /* Maximum allowed segments per level */
  char *zRank;                    /* Name of rank function */
  char *zRankArgs;                /* Arguments to rank function */

  /* If non-NULL, points to sqlite3_vtab.base.zErrmsg. Often NULL. */
  char **pzErrmsg;

#ifdef SQLITE_DEBUG
  int bPrefixIndex;               /* True to use prefix-indexes */
#endif
};

/* Current expected value of %_config table 'version' field */
#define FTS5_CURRENT_VERSION 4

#define FTS5_CONTENT_NORMAL   0
#define FTS5_CONTENT_NONE     1
#define FTS5_CONTENT_EXTERNAL 2




int sqlite3Fts5ConfigParse(
    Fts5Global*, sqlite3*, int, const char **, Fts5Config**, char**
);
void sqlite3Fts5ConfigFree(Fts5Config*);

int sqlite3Fts5ConfigDeclareVtab(Fts5Config *pConfig);

int sqlite3Fts5Tokenize(
  Fts5Config *pConfig,            /* FTS5 Configuration object */
  int flags,                      /* FTS5_TOKENIZE_* flags */
  const char *pText, int nText,   /* Text to tokenize */
  void *pCtx,                     /* Context passed to xToken() */
  int (*xToken)(void*, int, const char*, int, int, int)    /* Callback */
);

void sqlite3Fts5Dequote(char *z);

/* Load the contents of the %_config table */
int sqlite3Fts5ConfigLoad(Fts5Config*, int);

struct Fts5PoslistReader {
  /* Variables used only by sqlite3Fts5PoslistIterXXX() functions. */
  int iCol;                       /* If (iCol>=0), this column only */
  const u8 *a;                    /* Position list to iterate through */
  int n;                          /* Size of buffer at a[] in bytes */
  int i;                          /* Current offset in a[] */

  u8 bFlag;                       /* For client use (any custom purpose) */

  /* Output variables */
  u8 bEof;                        /* Set to true at EOF */
  i64 iPos;                       /* (iCol<<32) + iPos */
};
int sqlite3Fts5PoslistReaderInit(
  int iCol,                       /* If (iCol>=0), this column only */
  const u8 *a, int n,             /* Poslist buffer to iterate through */
  Fts5PoslistReader *pIter        /* Iterator object to initialize */
);

** to the database. Additionally, assume that the contents of the %_data
** table may have changed on disk. So any in-memory caches of %_data 
** records must be invalidated.
*/
int sqlite3Fts5IndexRollback(Fts5Index *p);

/*






** Get or set the "averages" values.
*/
int sqlite3Fts5IndexGetAverages(Fts5Index *p, i64 *pnRow, i64 *anSize);
int sqlite3Fts5IndexSetAverages(Fts5Index *p, const u8*, int);

/*
** Functions called by the storage module as part of integrity-check.
*/
u64 sqlite3Fts5IndexCksum(Fts5Config*,i64,int,int,const char*,int);
int sqlite3Fts5IndexIntegrityCheck(Fts5Index*, u64 cksum);

/* Called during startup to register a UDF with SQLite */
int sqlite3Fts5ExprInit(Fts5Global*, sqlite3*);

int sqlite3Fts5ExprPhraseCount(Fts5Expr*);
int sqlite3Fts5ExprPhraseSize(Fts5Expr*, int iPhrase);
int sqlite3Fts5ExprPoslist(Fts5Expr*, int, const u8 **);

int sqlite3Fts5ExprClonePhrase(Fts5Config*, Fts5Expr*, int, Fts5Expr**);

/*******************************************
** The fts5_expr.c API above this point is used by the other hand-written
** C code in this module. The interfaces below this point are called by
** the parser code in fts5parse.y.  */

void sqlite3Fts5ParseError(Fts5Parse *pParse, const char *zFmt, ...);

/**************************************************************************
** Interface to code in fts5_tokenizer.c. 
*/

int sqlite3Fts5TokenizerInit(fts5_api*);
/*
** End of interface to code in fts5_tokenizer.c.











**************************************************************************/

/**************************************************************************
** Interface to code in fts5_vocab.c. 
*/

int sqlite3Fts5VocabInit(Fts5Global*, sqlite3*);

}

/*
** Tokenizer callback used by implementation of highlight() function.
*/
static int fts5HighlightCb(
  void *pContext,                 /* Pointer to HighlightContext object */
  int tflags,                     /* Mask of FTS5_TOKEN_* flags */
  const char *pToken,             /* Buffer containing token */
  int nToken,                     /* Size of token in bytes */
  int iStartOff,                  /* Start offset of token */
  int iEndOff                     /* End offset of token */
){
  HighlightContext *p = (HighlightContext*)pContext;
  int rc = SQLITE_OK;
  int iPos;

  if( tflags & FTS5_TOKEN_COLOCATED ) return SQLITE_OK;
  iPos = p->iPos++;

  if( p->iRangeEnd>0 ){
    if( iPos<p->iRangeStart || iPos>p->iRangeEnd ) return SQLITE_OK;
    if( p->iRangeStart && iPos==p->iRangeStart ) p->iOff = iStartOff;
  }

  if( iPos==p->iter.iStart ){

*/



#include "fts5Int.h"

int sqlite3Fts5BufferGrow(int *pRc, Fts5Buffer *pBuf, int nByte){



  if( (pBuf->n + nByte) > pBuf->nSpace ){
    u8 *pNew;
    int nNew = pBuf->nSpace ? pBuf->nSpace*2 : 64;

    /* A no-op if an error has already occurred */
    if( *pRc ) return 1;

    while( nNew<(pBuf->n + nByte) ){
      nNew = nNew * 2;
    }
    pNew = sqlite3_realloc(pBuf->p, nNew);
    if( pNew==0 ){
      *pRc = SQLITE_NOMEM;
      return 1;

  nByte = nArg * (sizeof(char*) + sizeof(u8));
  pRet->azCol = (char**)sqlite3Fts5MallocZero(&rc, nByte);
  pRet->abUnindexed = (u8*)&pRet->azCol[nArg];
  pRet->zDb = sqlite3Fts5Strndup(&rc, azArg[1], -1);
  pRet->zName = sqlite3Fts5Strndup(&rc, azArg[2], -1);
  pRet->bColumnsize = 1;
#ifdef SQLITE_DEBUG
  pRet->bPrefixIndex = 1;
#endif
  if( rc==SQLITE_OK && sqlite3_stricmp(pRet->zName, FTS5_RANK_NAME)==0 ){
    *pzErr = sqlite3_mprintf("reserved fts5 table name: %s", pRet->zName);
    rc = SQLITE_ERROR;
  }

  for(i=3; rc==SQLITE_OK && i<nArg; i++){
    const char *zOrig = azArg[i];

** the callback returned SQLITE_DONE, this is not an error and this function
** still returns SQLITE_OK. Or, if the tokenization was abandoned early
** because the callback returned another non-zero value, it is assumed
** to be an SQLite error code and returned to the caller.
*/
int sqlite3Fts5Tokenize(
  Fts5Config *pConfig,            /* FTS5 Configuration object */
  int flags,                      /* FTS5_TOKENIZE_* flags */
  const char *pText, int nText,   /* Text to tokenize */
  void *pCtx,                     /* Context passed to xToken() */
  int (*xToken)(void*, int, const char*, int, int, int)    /* Callback */
){
  if( pText==0 ) return SQLITE_OK;
  return pConfig->pTokApi->xTokenize(
      pConfig->pTok, pCtx, flags, pText, nText, xToken
  );
}

/*
** Argument pIn points to the first character in what is expected to be
** a comma-separated list of SQL literals followed by a ')' character.
** If it actually is this, return a pointer to the ')'. Otherwise, return
** NULL to indicate a parse error.

#include "fts5parse.h"

/*
** All token types in the generated fts5parse.h file are greater than 0.
*/
#define FTS5_EOF 0

#define FTS5_LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))

typedef struct Fts5ExprTerm Fts5ExprTerm;

/*
** Functions generated by lemon from fts5parse.y.
*/
void *sqlite3Fts5ParserAlloc(void *(*mallocProc)(u64));
void sqlite3Fts5ParserFree(void*, void (*freeProc)(void*));

** An instance of the following structure represents a single search term
** or term prefix.
*/
struct Fts5ExprTerm {
  int bPrefix;                    /* True for a prefix term */
  char *zTerm;                    /* nul-terminated term */
  Fts5IndexIter *pIter;           /* Iterator for this term */
  Fts5ExprTerm *pSynonym;         /* Pointer to first in list of synonyms */
};

/*
** A phrase. One or more terms that must appear in a contiguous sequence
** within a document for it to match.
*/
struct Fts5ExprPhrase {

      }
      pToken->n = (z2 - z);
      break;
    }

    default: {
      const char *z2;
      if( sqlite3Fts5IsBareword(z[0])==0 ){
        sqlite3Fts5ParseError(pParse, "fts5: syntax error near \"%.1s\"", z);
        return FTS5_EOF;
      }
      tok = FTS5_STRING;
      for(z2=&z[1]; sqlite3Fts5IsBareword(*z2); z2++);
      pToken->n = (z2 - z);
      if( pToken->n==2 && memcmp(pToken->p, "OR", 2)==0 )  tok = FTS5_OR;
      if( pToken->n==3 && memcmp(pToken->p, "NOT", 3)==0 ) tok = FTS5_NOT;
      if( pToken->n==3 && memcmp(pToken->p, "AND", 3)==0 ) tok = FTS5_AND;
      break;

  }

  sqlite3_free(sParse.apPhrase);
  *pzErr = sParse.zErr;
  return sParse.rc;
}










































































/*
** Free the expression node object passed as the only argument.
*/
void sqlite3Fts5ParseNodeFree(Fts5ExprNode *p){
  if( p ){
    int i;
    for(i=0; i<p->nChild; i++){

static int fts5ExprColsetTest(Fts5ExprColset *pColset, int iCol){
  int i;
  for(i=0; i<pColset->nCol; i++){
    if( pColset->aiCol[i]==iCol ) return 1;
  }
  return 0;
}

/*
** Argument pTerm must be a synonym iterator. Return the current rowid
** that it points to.
*/
static i64 fts5ExprSynonymRowid(Fts5ExprTerm *pTerm, int bDesc, int *pbEof){
  i64 iRet = 0;
  int bRetValid = 0;
  Fts5ExprTerm *p;

  assert( pTerm->pSynonym );
  assert( bDesc==0 || bDesc==1 );
  for(p=pTerm; p; p=p->pSynonym){
    if( 0==sqlite3Fts5IterEof(p->pIter) ){
      i64 iRowid = sqlite3Fts5IterRowid(p->pIter);
      if( bRetValid==0 || (bDesc!=(iRowid<iRet)) ){
        iRet = iRowid;
        bRetValid = 1;
      }
    }
  }

  if( pbEof && bRetValid==0 ) *pbEof = 1;
  return iRet;
}

/*
** Argument pTerm must be a synonym iterator.
*/
static int fts5ExprSynonymPoslist(
  Fts5ExprTerm *pTerm, 
  i64 iRowid,
  int *pbDel,                     /* OUT: Caller should sqlite3_free(*pa) */
  u8 **pa, int *pn
){
  Fts5PoslistReader aStatic[4];
  Fts5PoslistReader *aIter = aStatic;
  int nIter = 0;
  int nAlloc = 4;
  int rc = SQLITE_OK;
  Fts5ExprTerm *p;

  assert( pTerm->pSynonym );
  for(p=pTerm; p; p=p->pSynonym){
    Fts5IndexIter *pIter = p->pIter;
    if( sqlite3Fts5IterEof(pIter)==0 && sqlite3Fts5IterRowid(pIter)==iRowid ){
      const u8 *a;
      int n;
      i64 dummy;
      rc = sqlite3Fts5IterPoslist(pIter, &a, &n, &dummy);
      if( rc!=SQLITE_OK ) goto synonym_poslist_out;
      if( nIter==nAlloc ){
        int nByte = sizeof(Fts5PoslistReader) * nAlloc * 2;
        Fts5PoslistReader *aNew = (Fts5PoslistReader*)sqlite3_malloc(nByte);
        if( aNew==0 ){
          rc = SQLITE_NOMEM;
          goto synonym_poslist_out;
        }
        memcpy(aNew, aIter, sizeof(Fts5PoslistReader) * nIter);
        nAlloc = nAlloc*2;
        if( aIter!=aStatic ) sqlite3_free(aIter);
        aIter = aNew;
      }
      sqlite3Fts5PoslistReaderInit(-1, a, n, &aIter[nIter]);
      assert( aIter[nIter].bEof==0 );
      nIter++;
    }
  }

  assert( *pbDel==0 );
  if( nIter==1 ){
    *pa = (u8*)aIter[0].a;
    *pn = aIter[0].n;
  }else{
    Fts5PoslistWriter writer = {0};
    Fts5Buffer buf = {0,0,0};
    i64 iPrev = -1;
    while( 1 ){
      int i;
      i64 iMin = FTS5_LARGEST_INT64;
      for(i=0; i<nIter; i++){
        if( aIter[i].bEof==0 ){
          if( aIter[i].iPos==iPrev ){
            if( sqlite3Fts5PoslistReaderNext(&aIter[i]) ) continue;
          }
          if( aIter[i].iPos<iMin ){
            iMin = aIter[i].iPos;
          }
        }
      }
      if( iMin==FTS5_LARGEST_INT64 || rc!=SQLITE_OK ) break;
      rc = sqlite3Fts5PoslistWriterAppend(&buf, &writer, iMin);
      iPrev = iMin;
    }
    if( rc ){
      sqlite3_free(buf.p);
    }else{
      *pa = buf.p;
      *pn = buf.n;
      *pbDel = 1;
    }
  }

 synonym_poslist_out:
  if( aIter!=aStatic ) sqlite3_free(aIter);
  return rc;
}


/*
** All individual term iterators in pPhrase are guaranteed to be valid and
** pointing to the same rowid when this function is called. This function 
** checks if the current rowid really is a match, and if so populates
** the pPhrase->poslist buffer accordingly. Output parameter *pbMatch
** is set to true if this is really a match, or false otherwise.
**
** SQLITE_OK is returned if an error occurs, or an SQLite error code 
** otherwise. It is not considered an error code if the current rowid is 
** not a match.
*/
static int fts5ExprPhraseIsMatch(
  Fts5ExprNode *pNode,            /* Node pPhrase belongs to */
  Fts5ExprColset *pColset,        /* Restrict matches to these columns */
  Fts5ExprPhrase *pPhrase,        /* Phrase object to initialize */
  int *pbMatch                    /* OUT: Set to true if really a match */
){
  Fts5PoslistWriter writer = {0};
  Fts5PoslistReader aStatic[4];
  Fts5PoslistReader *aIter = aStatic;

  /* If the aStatic[] array is not large enough, allocate a large array
  ** using sqlite3_malloc(). This approach could be improved upon. */
  if( pPhrase->nTerm>(sizeof(aStatic) / sizeof(aStatic[0])) ){
    int nByte = sizeof(Fts5PoslistReader) * pPhrase->nTerm;
    aIter = (Fts5PoslistReader*)sqlite3_malloc(nByte);
    if( !aIter ) return SQLITE_NOMEM;
  }
  memset(aIter, 0, sizeof(Fts5PoslistReader) * pPhrase->nTerm);

  /* Initialize a term iterator for each term in the phrase */
  for(i=0; i<pPhrase->nTerm; i++){
    Fts5ExprTerm *pTerm = &pPhrase->aTerm[i];
    i64 dummy;
    int n = 0;
    int bFlag = 0;
    const u8 *a = 0;
    if( pTerm->pSynonym ){
      rc = fts5ExprSynonymPoslist(pTerm, pNode->iRowid, &bFlag, (u8**)&a, &n);
    }else{
      rc = sqlite3Fts5IterPoslist(pTerm->pIter, &a, &n, &dummy);
    }
    if( rc!=SQLITE_OK ) goto ismatch_out;
    sqlite3Fts5PoslistReaderInit(iCol, a, n, &aIter[i]);
    aIter[i].bFlag = bFlag;
    if( aIter[i].bEof ) goto ismatch_out;

  }

  while( 1 ){
    int bMatch;
    i64 iPos = aIter[0].iPos;
    do {
      bMatch = 1;

    for(i=0; i<pPhrase->nTerm; i++){
      if( sqlite3Fts5PoslistReaderNext(&aIter[i]) ) goto ismatch_out;
    }
  }

 ismatch_out:
  *pbMatch = (pPhrase->poslist.n>0);
  for(i=0; i<pPhrase->nTerm; i++){
    if( aIter[i].bFlag ) sqlite3_free((u8*)aIter[i].a);
  }
  if( aIter!=aStatic ) sqlite3_free(aIter);
  return rc;
}

typedef struct Fts5LookaheadReader Fts5LookaheadReader;
struct Fts5LookaheadReader {
  const u8 *a;                    /* Buffer containing position list */

*/
static int fts5ExprNearAdvanceFirst(
  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
  Fts5ExprNode *pNode,            /* FTS5_STRING or FTS5_TERM node */
  int bFromValid,
  i64 iFrom 
){
  Fts5ExprTerm *pTerm = &pNode->pNear->apPhrase[0]->aTerm[0];
  int rc = SQLITE_OK;

  if( pTerm->pSynonym ){
    int bEof = 1;
    Fts5ExprTerm *p;

    /* Find the firstest rowid any synonym points to. */
    i64 iRowid = fts5ExprSynonymRowid(pTerm, pExpr->bDesc, 0);

    /* Advance each iterator that currently points to iRowid. Or, if iFrom
    ** is valid - each iterator that points to a rowid before iFrom.  */
    for(p=pTerm; p; p=p->pSynonym){
      if( sqlite3Fts5IterEof(p->pIter)==0 ){
        i64 ii = sqlite3Fts5IterRowid(p->pIter);
        if( ii==iRowid 
         || (bFromValid && ii!=iFrom && (ii>iFrom)==pExpr->bDesc) 
        ){
          if( bFromValid ){
            rc = sqlite3Fts5IterNextFrom(p->pIter, iFrom);
          }else{
            rc = sqlite3Fts5IterNext(p->pIter);
          }
          if( rc!=SQLITE_OK ) break;
          if( sqlite3Fts5IterEof(p->pIter)==0 ){
            bEof = 0;
          }
        }else{
          bEof = 0;
        }
      }
    }

    /* Set the EOF flag if either all synonym iterators are at EOF or an
    ** error has occurred.  */
    pNode->bEof = (rc || bEof);
  }else{
    Fts5IndexIter *pIter = pTerm->pIter;

    assert( Fts5NodeIsString(pNode) );
    if( bFromValid ){
      rc = sqlite3Fts5IterNextFrom(pIter, iFrom);
    }else{
      rc = sqlite3Fts5IterNext(pIter);
    }

    pNode->bEof = (rc || sqlite3Fts5IterEof(pIter));
  }

  return rc;
}

/*
** Advance iterator pIter until it points to a value equal to or laster
** than the initial value of *piLast. If this means the iterator points
** to a value laster than *piLast, update *piLast to the new lastest value.

    iRowid = sqlite3Fts5IterRowid(pIter);
    assert( (bDesc==0 && iRowid>=iLast) || (bDesc==1 && iRowid<=iLast) );
  }
  *piLast = iRowid;

  return 0;
}

static int fts5ExprSynonymAdvanceto(
  Fts5ExprTerm *pTerm,            /* Term iterator to advance */
  int bDesc,                      /* True if iterator is "rowid DESC" */
  i64 *piLast,                    /* IN/OUT: Lastest rowid seen so far */
  int *pRc                        /* OUT: Error code */
){
  int rc = SQLITE_OK;
  i64 iLast = *piLast;
  Fts5ExprTerm *p;
  int bEof = 0;

  for(p=pTerm; rc==SQLITE_OK && p; p=p->pSynonym){
    if( sqlite3Fts5IterEof(p->pIter)==0 ){
      i64 iRowid = sqlite3Fts5IterRowid(p->pIter);
      if( (bDesc==0 && iLast>iRowid) || (bDesc && iLast<iRowid) ){
        rc = sqlite3Fts5IterNextFrom(p->pIter, iLast);
      }
    }
  }

  if( rc!=SQLITE_OK ){
    *pRc = rc;
    bEof = 1;
  }else{
    *piLast = fts5ExprSynonymRowid(pTerm, bDesc, &bEof);
  }
  return bEof;
}

/*
** IN/OUT parameter (*pa) points to a position list n bytes in size. If
** the position list contains entries for column iCol, then (*pa) is set
** to point to the sub-position-list for that column and the number of
** bytes in it returned. Or, if the argument position list does not
** contain any entries for column iCol, return 0.

  int i;

  /* Check that each phrase in the nearset matches the current row.
  ** Populate the pPhrase->poslist buffers at the same time. If any
  ** phrase is not a match, break out of the loop early.  */
  for(i=0; rc==SQLITE_OK && i<pNear->nPhrase; i++){
    Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
    if( pPhrase->nTerm>1 || pPhrase->aTerm[0].pSynonym || pNear->pColset ){
      int bMatch = 0;
      rc = fts5ExprPhraseIsMatch(pNode, pNear->pColset, pPhrase, &bMatch);
      if( bMatch==0 ) break;
    }else{
      rc = sqlite3Fts5IterPoslistBuffer(
          pPhrase->aTerm[0].pIter, &pPhrase->poslist
      );
    }
  }

  Fts5ExprColset *pColset = pNear->pColset;
  const u8 *pPos;
  int nPos;
  int rc;

  assert( pNode->eType==FTS5_TERM );
  assert( pNear->nPhrase==1 && pPhrase->nTerm==1 );
  assert( pPhrase->aTerm[0].pSynonym==0 );

  rc = sqlite3Fts5IterPoslist(pIter, &pPos, &nPos, &pNode->iRowid);

  /* If the term may match any column, then this must be a match. 
  ** Return immediately in this case. Otherwise, try to find the
  ** part of the poslist that corresponds to the required column.
  ** If it can be found, return. If it cannot, the next iteration

){
  Fts5ExprNearset *pNear = pNode->pNear;
  Fts5ExprPhrase *pLeft = pNear->apPhrase[0];
  int rc = SQLITE_OK;
  i64 iLast;                      /* Lastest rowid any iterator points to */
  int i, j;                       /* Phrase and token index, respectively */
  int bMatch;                     /* True if all terms are at the same rowid */
  const int bDesc = pExpr->bDesc;

  /* Check that this node should not be FTS5_TERM */
  assert( pNear->nPhrase>1 
       || pNear->apPhrase[0]->nTerm>1 
       || pNear->apPhrase[0]->aTerm[0].pSynonym
  );

  /* Initialize iLast, the "lastest" rowid any iterator points to. If the
  ** iterator skips through rowids in the default ascending order, this means
  ** the maximum rowid. Or, if the iterator is "ORDER BY rowid DESC", then it
  ** means the minimum rowid.  */
  if( pLeft->aTerm[0].pSynonym ){
    iLast = fts5ExprSynonymRowid(&pLeft->aTerm[0], bDesc, 0);
  }else{
    iLast = sqlite3Fts5IterRowid(pLeft->aTerm[0].pIter);
  }

  do {
    bMatch = 1;
    for(i=0; i<pNear->nPhrase; i++){
      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
      for(j=0; j<pPhrase->nTerm; j++){
        Fts5ExprTerm *pTerm = &pPhrase->aTerm[j];
        if( pTerm->pSynonym ){
          i64 iRowid = fts5ExprSynonymRowid(pTerm, bDesc, 0);
          if( iRowid==iLast ) continue;
          bMatch = 0;
          if( fts5ExprSynonymAdvanceto(pTerm, bDesc, &iLast, &rc) ){
            pNode->bEof = 1;
            return rc;
          }
        }else{
          Fts5IndexIter *pIter = pPhrase->aTerm[j].pIter;
          i64 iRowid = sqlite3Fts5IterRowid(pIter);
          if( iRowid==iLast ) continue;
          bMatch = 0;
          if( fts5ExprAdvanceto(pIter, bDesc, &iLast, &rc, &pNode->bEof) ){
            return rc;
          }
        }
      }
    }
  }while( bMatch==0 );


  pNode->iRowid = iLast;
  pNode->bNomatch = (0==fts5ExprNearTest(&rc, pExpr, pNode));

  return rc;
}

/*
** Initialize all term iterators in the pNear object. If any term is found
** to match no documents at all, return immediately without initializing any
** further iterators.
*/
static int fts5ExprNearInitAll(
  Fts5Expr *pExpr,
  Fts5ExprNode *pNode
){
  Fts5ExprNearset *pNear = pNode->pNear;


  int i, j;
  int rc = SQLITE_OK;

  for(i=0; rc==SQLITE_OK && i<pNear->nPhrase; i++){
    Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
    for(j=0; j<pPhrase->nTerm; j++){
      Fts5ExprTerm *pTerm = &pPhrase->aTerm[j];
      Fts5ExprTerm *p;
      int bEof = 1;

      for(p=pTerm; p && rc==SQLITE_OK; p=p->pSynonym){
        if( p->pIter ){
          sqlite3Fts5IterClose(p->pIter);
          p->pIter = 0;
        }
        rc = sqlite3Fts5IndexQuery(
            pExpr->pIndex, p->zTerm, strlen(p->zTerm),
            (pTerm->bPrefix ? FTS5INDEX_QUERY_PREFIX : 0) |
            (pExpr->bDesc ? FTS5INDEX_QUERY_DESC : 0),
            &p->pIter
        );
        assert( rc==SQLITE_OK || p->pIter==0 );
        if( p->pIter && 0==sqlite3Fts5IterEof(p->pIter) ){
          bEof = 0;
        }
      }

      if( bEof ){
        pNode->bEof = 1;
        return rc;
      }
    }
  }

  return rc;
}

    switch( pNode->eType ){
      case FTS5_STRING: {
        rc = fts5ExprNearAdvanceFirst(pExpr, pNode, bFromValid, iFrom);
        break;
      };

      case FTS5_TERM: {
        Fts5IndexIter *pIter = pNode->pNear->apPhrase[0]->aTerm[0].pIter;
        if( bFromValid ){
          rc = sqlite3Fts5IterNextFrom(pIter, iFrom);
        }else{
          rc = sqlite3Fts5IterNext(pIter);
        }
        if( rc==SQLITE_OK && sqlite3Fts5IterEof(pIter)==0 ){
          assert( rc==SQLITE_OK );
          rc = fts5ExprTokenTest(pExpr, pNode);
        }else{
          pNode->bEof = 1;
        }
        return rc;
      };

      case FTS5_AND: {
        Fts5ExprNode *pLeft = pNode->apChild[0];
        rc = fts5ExprNodeNext(pExpr, pLeft, bFromValid, iFrom);

/*
** Free the phrase object passed as the only argument.
*/
static void fts5ExprPhraseFree(Fts5ExprPhrase *pPhrase){
  if( pPhrase ){
    int i;
    for(i=0; i<pPhrase->nTerm; i++){
      Fts5ExprTerm *pSyn;
      Fts5ExprTerm *pNext;
      Fts5ExprTerm *pTerm = &pPhrase->aTerm[i];
      sqlite3_free(pTerm->zTerm);
      sqlite3Fts5IterClose(pTerm->pIter);

      for(pSyn=pTerm->pSynonym; pSyn; pSyn=pNext){
        pNext = pSyn->pSynonym;
        sqlite3Fts5IterClose(pSyn->pIter);
        sqlite3_free(pSyn);
      }
    }
    if( pPhrase->poslist.nSpace>0 ) fts5BufferFree(&pPhrase->poslist);
    sqlite3_free(pPhrase);
  }
}

  }
  return pRet;
}

typedef struct TokenCtx TokenCtx;
struct TokenCtx {
  Fts5ExprPhrase *pPhrase;
  int rc;
};

/*
** Callback for tokenizing terms used by ParseTerm().
*/
static int fts5ParseTokenize(
  void *pContext,                 /* Pointer to Fts5InsertCtx object */
  int tflags,                     /* Mask of FTS5_TOKEN_* flags */
  const char *pToken,             /* Buffer containing token */
  int nToken,                     /* Size of token in bytes */
  int iUnused1,                   /* Start offset of token */
  int iUnused2                    /* End offset of token */
){
  int rc = SQLITE_OK;
  const int SZALLOC = 8;
  TokenCtx *pCtx = (TokenCtx*)pContext;
  Fts5ExprPhrase *pPhrase = pCtx->pPhrase;

  /* If an error has already occurred, this is a no-op */
  if( pCtx->rc!=SQLITE_OK ) return pCtx->rc;

  assert( pPhrase==0 || pPhrase->nTerm>0 );
  if( pPhrase && (tflags & FTS5_TOKEN_COLOCATED) ){
    Fts5ExprTerm *pSyn;
    int nByte = sizeof(Fts5ExprTerm) + nToken+1;
    pSyn = (Fts5ExprTerm*)sqlite3_malloc(nByte);
    if( pSyn==0 ){
      rc = SQLITE_NOMEM;
    }else{
      memset(pSyn, 0, nByte);
      pSyn->zTerm = (char*)&pSyn[1];
      memcpy(pSyn->zTerm, pToken, nToken);
      pSyn->pSynonym = pPhrase->aTerm[pPhrase->nTerm-1].pSynonym;
      pPhrase->aTerm[pPhrase->nTerm-1].pSynonym = pSyn;
    }
  }else{
    Fts5ExprTerm *pTerm;
    if( pPhrase==0 || (pPhrase->nTerm % SZALLOC)==0 ){
      Fts5ExprPhrase *pNew;
      int nNew = SZALLOC + (pPhrase ? pPhrase->nTerm : 0);

      pNew = (Fts5ExprPhrase*)sqlite3_realloc(pPhrase, 
          sizeof(Fts5ExprPhrase) + sizeof(Fts5ExprTerm) * nNew
      );
      if( pNew==0 ){
        rc = SQLITE_NOMEM;
      }else{
        if( pPhrase==0 ) memset(pNew, 0, sizeof(Fts5ExprPhrase));
        pCtx->pPhrase = pPhrase = pNew;
        pNew->nTerm = nNew - SZALLOC;
      }
    }

    if( rc==SQLITE_OK ){
      pTerm = &pPhrase->aTerm[pPhrase->nTerm++];
      memset(pTerm, 0, sizeof(Fts5ExprTerm));
      pTerm->zTerm = sqlite3Fts5Strndup(&rc, pToken, nToken);
    }
  }

  pCtx->rc = rc;
  return rc;
}


/*
** Free the phrase object passed as the only argument.
*/

  char *z = 0;

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

  rc = fts5ParseStringFromToken(pToken, &z);
  if( rc==SQLITE_OK ){
    int flags = FTS5_TOKENIZE_QUERY | (bPrefix ? FTS5_TOKENIZE_QUERY : 0);
    int n;
    sqlite3Fts5Dequote(z);
    n = strlen(z);
    rc = sqlite3Fts5Tokenize(pConfig, flags, z, n, &sCtx, fts5ParseTokenize);
  }
  sqlite3_free(z);
  if( rc || (rc = sCtx.rc) ){
    pParse->rc = rc;
    fts5ExprPhraseFree(sCtx.pPhrase);
    sCtx.pPhrase = 0;
  }else if( sCtx.pPhrase ){

    if( pAppend==0 ){
      if( (pParse->nPhrase % 8)==0 ){

    pParse->apPhrase[pParse->nPhrase-1] = sCtx.pPhrase;
    assert( sCtx.pPhrase->nTerm>0 );
    sCtx.pPhrase->aTerm[sCtx.pPhrase->nTerm-1].bPrefix = bPrefix;
  }

  return sCtx.pPhrase;
}

/*
** Create a new FTS5 expression by cloning phrase iPhrase of the
** expression passed as the second argument.
*/
int sqlite3Fts5ExprClonePhrase(
  Fts5Config *pConfig,
  Fts5Expr *pExpr, 
  int iPhrase, 
  Fts5Expr **ppNew
){
  int rc = SQLITE_OK;             /* Return code */
  Fts5ExprPhrase *pOrig;          /* The phrase extracted from pExpr */
  int i;                          /* Used to iterate through phrase terms */

  Fts5Expr *pNew = 0;             /* Expression to return via *ppNew */

  TokenCtx sCtx = {0,0};          /* Context object for fts5ParseTokenize */


  pOrig = pExpr->apExprPhrase[iPhrase];

  pNew = (Fts5Expr*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Expr));
  if( rc==SQLITE_OK ){
    pNew->apExprPhrase = (Fts5ExprPhrase**)sqlite3Fts5MallocZero(&rc, 
        sizeof(Fts5ExprPhrase*));
  }
  if( rc==SQLITE_OK ){
    pNew->pRoot = (Fts5ExprNode*)sqlite3Fts5MallocZero(&rc, 
        sizeof(Fts5ExprNode));
  }
  if( rc==SQLITE_OK ){
    pNew->pRoot->pNear = (Fts5ExprNearset*)sqlite3Fts5MallocZero(&rc, 
        sizeof(Fts5ExprNearset) + sizeof(Fts5ExprPhrase*));
  }

  for(i=0; rc==SQLITE_OK && i<pOrig->nTerm; i++){
    int tflags = 0;
    Fts5ExprTerm *p;
    for(p=&pOrig->aTerm[i]; p && rc==SQLITE_OK; p=p->pSynonym){
      const char *zTerm = p->zTerm;
      rc = fts5ParseTokenize((void*)&sCtx, tflags, zTerm, strlen(zTerm), 0, 0);
      tflags = FTS5_TOKEN_COLOCATED;
    }
    if( rc==SQLITE_OK ){
      sCtx.pPhrase->aTerm[i].bPrefix = pOrig->aTerm[i].bPrefix;
    }
  }

  if( rc==SQLITE_OK ){
    /* All the allocations succeeded. Put the expression object together. */
    pNew->pIndex = pExpr->pIndex;
    pNew->nPhrase = 1;
    pNew->apExprPhrase[0] = sCtx.pPhrase;
    pNew->pRoot->pNear->apPhrase[0] = sCtx.pPhrase;
    pNew->pRoot->pNear->nPhrase = 1;
    sCtx.pPhrase->pNode = pNew->pRoot;

    if( pOrig->nTerm==1 && pOrig->aTerm[0].pSynonym==0 ){
      pNew->pRoot->eType = FTS5_TERM;
    }else{
      pNew->pRoot->eType = FTS5_STRING;
    }
  }else{
    sqlite3Fts5ExprFree(pNew);
    fts5ExprPhraseFree(sCtx.pPhrase);
    pNew = 0;
  }

  *ppNew = pNew;
  return rc;
}


/*
** Token pTok has appeared in a MATCH expression where the NEAR operator
** is expected. If token pTok does not contain "NEAR", store an error
** in the pParse object.
*/
void sqlite3Fts5ParseNear(Fts5Parse *pParse, Fts5Token *pTok){

      pRet->eType = eType;
      pRet->pNear = pNear;
      if( eType==FTS5_STRING ){
        int iPhrase;
        for(iPhrase=0; iPhrase<pNear->nPhrase; iPhrase++){
          pNear->apPhrase[iPhrase]->pNode = pRet;
        }
        if( pNear->nPhrase==1 
         && pNear->apPhrase[0]->nTerm==1 
         && pNear->apPhrase[0]->aTerm[0].pSynonym==0
        ){
          pRet->eType = FTS5_TERM;
        }
      }else{
        fts5ExprAddChildren(pRet, pLeft);
        fts5ExprAddChildren(pRet, pRight);
      }
    }
  }

  if( pRet==0 ){
    assert( pParse->rc!=SQLITE_OK );
    sqlite3Fts5ParseNodeFree(pLeft);
    sqlite3Fts5ParseNodeFree(pRight);
    sqlite3Fts5ParseNearsetFree(pNear);
  }
  return pRet;
}

static char *fts5ExprTermPrint(Fts5ExprTerm *pTerm){
  int nByte = 0;
  Fts5ExprTerm *p;
  char *zQuoted;

  /* Determine the maximum amount of space required. */
  for(p=pTerm; p; p=p->pSynonym){
    nByte += strlen(pTerm->zTerm) * 2 + 3 + 2;
  }
  zQuoted = sqlite3_malloc(nByte);

  if( zQuoted ){
    int i = 0;
    for(p=pTerm; p; p=p->pSynonym){
      char *zIn = p->zTerm;
      zQuoted[i++] = '"';
      while( *zIn ){
        if( *zIn=='"' ) zQuoted[i++] = '"';
        zQuoted[i++] = *zIn++;
      }
      zQuoted[i++] = '"';
      if( p->pSynonym ) zQuoted[i++] = '|';
    }
    if( pTerm->bPrefix ){
      zQuoted[i++] = ' ';
      zQuoted[i++] = '*';
    }
    zQuoted[i++] = '\0';
  }
  return zQuoted;

**
**   Then, for each level from 0 to nMax:
**
**     + number of input segments in ongoing merge.
**     + total number of segments in level.
**     + for each segment from oldest to newest:
**         + segment id (always > 0)

**         + first leaf page number (often 1, always greater than 0)
**         + final leaf page number
**
** 2. The Averages Record:
**
**   A single record within the %_data table. The data is a list of varints.
**   The first value is the number of rows in the index. Then, for each column
**   from left to right, the total number of tokens in the column for all
**   rows of the table.
**
** 3. Segment leaves:
**
**   TERM/DOCLIST FORMAT:
**
**     Most of each segment leaf is taken up by term/doclist data. The 
**     general format of term/doclist, starting with the first term
**     on the leaf page, is:
**
**         varint : size of first term
**         blob:    first term data
**         doclist: first doclist
**         zero-or-more {
**           varint:  number of bytes in common with previous term
**           varint:  number of bytes of new term data (nNew)
**           blob:    nNew bytes of new term data
**           doclist: next doclist
**         }
**
**     doclist format:
**
**         varint:  first rowid
**         poslist: first poslist
**         zero-or-more {
**           varint:  rowid delta (always > 0)
**           poslist: next poslist
**         }

**
**     poslist format:
**
**         varint: size of poslist in bytes multiplied by 2, not including
**                 this field. Plus 1 if this entry carries the "delete" flag.
**         collist: collist for column 0
**         zero-or-more {
**           0x01 byte
**           varint: column number (I)
**           collist: collist for column I
**         }
**
**     collist format:
**
**         varint: first offset + 2
**         zero-or-more {
**           varint: offset delta + 2
**         }
**
**   PAGE FORMAT
**
**     Each leaf page begins with a 4-byte header containing 2 16-bit 
**     unsigned integer fields in big-endian format. They are:
**
**       * The byte offset of the first rowid on the page, if it exists
**         and occurs before the first term (otherwise 0).
**
**       * The byte offset of the start of the page footer. If the page
**         footer is 0 bytes in size, then this field is the same as the
**         size of the leaf page in bytes.
**
**     The page footer consists of a single varint for each term located
**     on the page. Each varint is the byte offset of the current term
**     within the page, delta-compressed against the previous value. In
**     other words, the first varint in the footer is the byte offset of
**     the first term, the second is the byte offset of the second less that
**     of the first, and so on.
**
**     The term/doclist format described above is accurate if the entire
**     term/doclist data fits on a single leaf page. If this is not the case,
**     the format is changed in two ways:
**
**       + if the first rowid on a page occurs before the first term, it
**         is stored as a literal value:
**
**             varint:  first rowid
**
**       + the first term on each page is stored in the same way as the
**         very first term of the segment:
**
**             varint : size of first term
**             blob:    first term data
**







































** 5. Segment doclist indexes:
**
**   Doclist indexes are themselves b-trees, however they usually consist of
**   a single leaf record only. The format of each doclist index leaf page 
**   is:
**
**     * Flags byte. Bits are:

/*
** Rowids for the averages and structure records in the %_data table.
*/
#define FTS5_AVERAGES_ROWID     1    /* Rowid used for the averages record */
#define FTS5_STRUCTURE_ROWID   10    /* The structure record */

/*
** Macros determining the rowids used by segment leaves and dlidx leaves

** and nodes. All nodes and leaves are stored in the %_data table with large
** positive rowids.


**
** Each segment has a unique non-zero 16-bit id.
**





** The rowid for each segment leaf is found by passing the segment id and 

** the leaf page number to the FTS5_SEGMENT_ROWID macro. Leaves are numbered

** sequentially starting from 1.
*/
#define FTS5_DATA_ID_B     16     /* Max seg id number 65535 */
#define FTS5_DATA_DLI_B     1     /* Doclist-index flag (1 bit) */
#define FTS5_DATA_HEIGHT_B  5     /* Max dlidx tree height of 32 */
#define FTS5_DATA_PAGE_B   31     /* Max page number of 2147483648 */

#define fts5_dri(segid, dlidx, height, pgno) (                                 \
 ((i64)(segid)  << (FTS5_DATA_PAGE_B+FTS5_DATA_HEIGHT_B+FTS5_DATA_DLI_B)) +    \
 ((i64)(dlidx)  << (FTS5_DATA_PAGE_B + FTS5_DATA_HEIGHT_B)) +                  \
 ((i64)(height) << (FTS5_DATA_PAGE_B)) +                                       \
 ((i64)(pgno))                                                                 \
)

#define FTS5_SEGMENT_ROWID(segid, pgno)       fts5_dri(segid, 0, 0, pgno)
#define FTS5_DLIDX_ROWID(segid, height, pgno) fts5_dri(segid, 1, height, pgno)

/*
** Maximum segments permitted in a single index 
*/
#define FTS5_MAX_SEGMENT 2000

#ifdef SQLITE_DEBUG

#define FTS5_DATA_ZERO_PADDING 8
#define FTS5_DATA_PADDING 20

typedef struct Fts5Data Fts5Data;
typedef struct Fts5DlidxIter Fts5DlidxIter;
typedef struct Fts5DlidxLvl Fts5DlidxLvl;
typedef struct Fts5DlidxWriter Fts5DlidxWriter;

typedef struct Fts5PageWriter Fts5PageWriter;
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 nn;                         /* Size of record in bytes */
  int szLeaf;                     /* Size of leaf without page-index */
};

/*
** One object per %_data table.
*/
struct Fts5Index {
  Fts5Config *pConfig;            /* Virtual table configuration */

/*
** The contents of the "structure" record for each index are represented
** using an Fts5Structure record in memory. Which uses instances of the 
** other Fts5StructureXXX types as components.
*/
struct Fts5StructureSegment {
  int iSegid;                     /* Segment id */

  int pgnoFirst;                  /* First leaf page number in segment */
  int pgnoLast;                   /* Last leaf page number in segment */
};
struct Fts5StructureLevel {
  int nMerge;                     /* Number of segments in incr-merge */
  int nSeg;                       /* Total number of segments on level */
  Fts5StructureSegment *aSeg;     /* Array of segments. aSeg[0] is oldest. */

};

/*
** An object of type Fts5SegWriter is used to write to segments.
*/
struct Fts5PageWriter {
  int pgno;                       /* Page number for this page */
  int iPrevPgidx;                 /* Previous value written into pgidx */
  Fts5Buffer buf;                 /* Buffer containing leaf data */
  Fts5Buffer pgidx;               /* Buffer containing page-index */
  Fts5Buffer term;                /* Buffer containing previous term on page */
};
struct Fts5DlidxWriter {
  int pgno;                       /* Page number for this page */
  int bPrevValid;                 /* True if iPrev is valid */
  i64 iPrev;                      /* Previous rowid value written to page */
  Fts5Buffer buf;                 /* Buffer containing page data */
};
struct Fts5SegWriter {
  int iSegid;                     /* Segid to write to */
  Fts5PageWriter writer;          /* PageWriter object */
  i64 iPrevRowid;                 /* Previous rowid written to current leaf */
  u8 bFirstRowidInDoclist;        /* True if next rowid is first in doclist */
  u8 bFirstRowidInPage;           /* True if next rowid is first in page */
  /* TODO1: Can use (writer.pgidx.n==0) instead of bFirstTermInPage */
  u8 bFirstTermInPage;            /* True if next term will be first in leaf */
  int nLeafWritten;               /* Number of leaf pages written */
  int nEmpty;                     /* Number of contiguous term-less nodes */

  int nDlidx;                     /* Allocated size of aDlidx[] array */
  Fts5DlidxWriter *aDlidx;        /* Array of Fts5DlidxWriter objects */

**
** iRowidOffset/nRowidOffset/aRowidOffset:
**     These are used if the FTS5_SEGITER_REVERSE flag is set.
**
**     For each rowid on the page corresponding to the current term, the
**     corresponding aRowidOffset[] entry is set to the byte offset of the
**     start of the "position-list-size" field within the page.
**
** iTermIdx:
**     Index of current term on iTermLeafPgno.
*/
struct Fts5SegIter {
  Fts5StructureSegment *pSeg;     /* Segment to iterate through */
  int flags;                      /* Mask of configuration flags */
  int iLeafPgno;                  /* Current leaf page number */
  Fts5Data *pLeaf;                /* Current leaf data */
  Fts5Data *pNextLeaf;            /* Leaf page (iLeafPgno+1) */
  int iLeafOffset;                /* Byte offset within current leaf */

  /* The page and offset from which the current term was read. The offset 
  ** is the offset of the first rowid in the current doclist.  */
  int iTermLeafPgno;
  int iTermLeafOffset;

  int iPgidxOff;                  /* Next offset in pgidx */
  int iEndofDoclist;

  /* The following are only used if the FTS5_SEGITER_REVERSE flag is set. */
  int iRowidOffset;               /* Current entry in aRowidOffset[] */
  int nRowidOffset;               /* Allocated size of aRowidOffset[] array */
  int *aRowidOffset;              /* Array of offset to rowid fields */

  Fts5DlidxIter *pDlidx;          /* If there is a doclist-index */

  /* Variables populated based on current entry. */
  Fts5Buffer term;                /* Current term */
  i64 iRowid;                     /* Current rowid */
  int nPos;                       /* Number of bytes in current position list */
  int bDel;                       /* True if the delete flag is set */
};

/*
** Argument is a pointer to an Fts5Data structure that contains a 
** leaf page.
*/
#define ASSERT_SZLEAF_OK(x) assert( \
    (x)->szLeaf==(x)->nn || (x)->szLeaf==fts5GetU16(&(x)->p[2]) \
)

#define FTS5_SEGITER_ONETERM 0x01
#define FTS5_SEGITER_REVERSE 0x02


/* 
** Argument is a pointer to an Fts5Data structure that contains a leaf
** page. This macro evaluates to true if the leaf contains no terms, or
** false if it contains at least one term.
*/
#define fts5LeafIsTermless(x) ((x)->szLeaf >= (x)->nn)

#define fts5LeafTermOff(x, i) (fts5GetU16(&(x)->p[(x)->szLeaf + (i)*2]))

#define fts5LeafFirstRowidOff(x) (fts5GetU16((x)->p))

/*
** poslist:
**   Used by sqlite3Fts5IterPoslist() when the poslist needs to be buffered.
**   There is no way to tell if this is populated or not.
*/
struct Fts5IndexIter {
  Fts5Index *pIndex;              /* Index that owns this iterator */

  i64 iSwitchRowid;               /* Firstest rowid of other than aFirst[1] */
  Fts5CResult *aFirst;            /* Current merge state (see above) */
  Fts5SegIter aSeg[1];            /* Array of segment iterators */
};




















/*
** An instance of the following type is used to iterate through the contents
** of a doclist-index record.
**
** pData:
**   Record containing the doclist-index data.
**

};
struct Fts5DlidxIter {
  int nLvl;
  int iSegid;
  Fts5DlidxLvl aLvl[1];
};


















static void fts5PutU16(u8 *aOut, u16 iVal){
  aOut[0] = (iVal>>8);
  aOut[1] = (iVal&0xFF);
}

static u16 fts5GetU16(const u8 *aIn){
  return ((u16)aIn[0] << 8) + aIn[1];

** Compare the contents of the pLeft buffer with the pRight/nRight blob.
**
** Return -ve if pLeft is smaller than pRight, 0 if they are equal or
** +ve if pRight is smaller than pLeft. In other words:
**
**     res = *pLeft - *pRight
*/
#ifdef SQLITE_DEBUG
static int fts5BufferCompareBlob(
  Fts5Buffer *pLeft,              /* Left hand side of comparison */
  const u8 *pRight, int nRight    /* Right hand side of comparison */
){
  int nCmp = MIN(pLeft->n, nRight);
  int res = memcmp(pLeft->p, pRight, nCmp);
  return (res==0 ? (pLeft->n - nRight) : res);
}
#endif

/*
** Compare the contents of the two buffers using memcmp(). If one buffer
** is a prefix of the other, it is considered the lesser.
**
** Return -ve if pLeft is smaller than pRight, 0 if they are equal or
** +ve if pRight is smaller than pLeft. In other words:

){
  int nCmp = MIN(nLeft, nRight);
  int res = memcmp(pLeft, pRight, nCmp);
  return (res==0 ? (nLeft - nRight) : res);
}
#endif

static int fts5LeafFirstTermOff(Fts5Data *pLeaf){
  int ret;
  fts5GetVarint32(&pLeaf->p[pLeaf->szLeaf], ret);
  return ret;
}

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


/*
** Retrieve a record from the %_data table.
**
** If an error occurs, NULL is returned and an error left in the 
** Fts5Index object.
*/
static Fts5Data *fts5DataRead(Fts5Index *p, i64 iRowid){

  Fts5Data *pRet = 0;
  if( p->rc==SQLITE_OK ){
    int rc = SQLITE_OK;

    if( p->pReader ){
      /* This call may return SQLITE_ABORT if there has been a savepoint
      ** rollback since it was last used. In this case a new blob handle
      ** is required.  */
      sqlite3_blob *pBlob = p->pReader;
      p->pReader = 0;
      rc = sqlite3_blob_reopen(pBlob, iRowid);
      assert( p->pReader==0 );
      p->pReader = pBlob;
      if( rc!=SQLITE_OK ){
        fts5CloseReader(p);
      }
      if( rc==SQLITE_ABORT ) rc = SQLITE_OK;
    }

    /* If the blob handle is not open at this point, open it and seek 
    ** to the requested entry.  */
    if( p->pReader==0 && rc==SQLITE_OK ){
      Fts5Config *pConfig = p->pConfig;
      rc = sqlite3_blob_open(pConfig->db, 
          pConfig->zDb, p->zDataTbl, "block", iRowid, 0, &p->pReader
      );
    }

    /* If either of the sqlite3_blob_open() or sqlite3_blob_reopen() calls
    ** above returned SQLITE_ERROR, return SQLITE_CORRUPT_VTAB instead.
    ** All the reasons those functions might return SQLITE_ERROR - missing
    ** table, missing row, non-blob/text in block column - indicate 
    ** backing store corruption.  */
    if( rc==SQLITE_ERROR ) rc = FTS5_CORRUPT;

    if( rc==SQLITE_OK ){
      u8 *aOut = 0;               /* Read blob data into this buffer */
      int nByte = sqlite3_blob_bytes(p->pReader);








      int nAlloc = sizeof(Fts5Data) + nByte + FTS5_DATA_PADDING;
      pRet = (Fts5Data*)sqlite3_malloc(nAlloc);
      if( pRet ){
        pRet->nn = nByte;
        aOut = pRet->p = (u8*)&pRet[1];
      }else{
        rc = SQLITE_NOMEM;

      }

      if( rc==SQLITE_OK ){
        rc = sqlite3_blob_read(p->pReader, aOut, nByte, 0);
      }
      if( rc!=SQLITE_OK ){
        sqlite3_free(pRet);
        pRet = 0;
      }else{
        /* TODO1: Fix this */
        pRet->szLeaf = fts5GetU16(&pRet->p[2]);
      }
    }
    p->rc = rc;
    p->nRead++;
  }












  assert( (pRet==0)==(p->rc!=SQLITE_OK) );
  return pRet;
}













/*
** Release a reference to data record returned by an earlier call to
** fts5DataRead().
*/
static void fts5DataRelease(Fts5Data *pData){
  sqlite3_free(pData);
}

/*
** INSERT OR REPLACE a record into the %_data table.
*/
static void fts5DataWrite(Fts5Index *p, i64 iRowid, const u8 *pData, int nData){
  if( p->rc!=SQLITE_OK ) return;

  if( p->pWriter==0 ){

    Fts5Config *pConfig = p->pConfig;
    fts5IndexPrepareStmt(p, &p->pWriter, sqlite3_mprintf(
          "REPLACE INTO '%q'.'%q_data'(id, block) VALUES(?,?)", 
          pConfig->zDb, pConfig->zName
    ));
    if( p->rc ) return;
  }

  p->rc = sqlite3_reset(p->pDeleter);
}

/*
** Remove all records associated with segment iSegid.
*/
static void fts5DataRemoveSegment(Fts5Index *p, int iSegid){
  i64 iFirst = FTS5_SEGMENT_ROWID(iSegid, 0);
  i64 iLast = FTS5_SEGMENT_ROWID(iSegid+1, 0)-1;
  fts5DataDelete(p, iFirst, iLast);
  if( p->pIdxDeleter==0 ){
    Fts5Config *pConfig = p->pConfig;
    fts5IndexPrepareStmt(p, &p->pIdxDeleter, sqlite3_mprintf(
          "DELETE FROM '%q'.'%q_idx' WHERE segid=?",
          pConfig->zDb, pConfig->zName
    ));

          nTotal * sizeof(Fts5StructureSegment)
      );

      if( rc==SQLITE_OK ){
        pLvl->nSeg = nTotal;
        for(iSeg=0; iSeg<nTotal; iSeg++){
          i += fts5GetVarint32(&pData[i], pLvl->aSeg[iSeg].iSegid);

          i += fts5GetVarint32(&pData[i], pLvl->aSeg[iSeg].pgnoFirst);
          i += fts5GetVarint32(&pData[i], pLvl->aSeg[iSeg].pgnoLast);
        }
      }else{
        fts5StructureRelease(pRet);
        pRet = 0;
      }

** Fts5Index handle. If an error has already occurred when this function
** is called, it is a no-op.
*/
static Fts5Structure *fts5StructureRead(Fts5Index *p){
  Fts5Config *pConfig = p->pConfig;
  Fts5Structure *pRet = 0;        /* Object to return */
  int iCookie;                    /* Configuration cookie */
  Fts5Data *pData;

  pData = fts5DataRead(p, FTS5_STRUCTURE_ROWID);
  if( p->rc ) return 0;
  /* TODO: Do we need this if the leaf-index is appended? Probably... */
  memset(&pData->p[pData->nn], 0, FTS5_DATA_PADDING);
  p->rc = fts5StructureDecode(pData->p, pData->nn, &iCookie, &pRet);

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

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

      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].pgnoFirst);
        fts5BufferAppendVarint(&p->rc, &buf, pLvl->aSeg[iSeg].pgnoLast);
      }
    }

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

){
  if( p->rc==SQLITE_OK ){
    int iTst;
    int iPromote = -1;
    int szPromote = 0;            /* Promote anything this size or smaller */
    Fts5StructureSegment *pSeg;   /* Segment just written */
    int szSeg;                    /* Size of segment just written */
    int nSeg = pStruct->aLevel[iLvl].nSeg;

    if( nSeg==0 ) return;
    pSeg = &pStruct->aLevel[iLvl].aSeg[pStruct->aLevel[iLvl].nSeg-1];
    szSeg = (1 + pSeg->pgnoLast - pSeg->pgnoFirst);

    /* Check for condition (a) */
    for(iTst=iLvl-1; iTst>=0 && pStruct->aLevel[iTst].nSeg==0; iTst--);
    if( iTst>=0 ){
      int i;

      szPromote = szSeg;
    }
    fts5StructurePromoteTo(p, iPromote, szPromote, pStruct);
  }
}


























































/*
** Advance the iterator passed as the only argument. If the end of the 
** doclist-index page is reached, return non-zero.
*/
static int fts5DlidxLvlNext(Fts5DlidxLvl *pLvl){
  Fts5Data *pData = pLvl->pData;

  if( pLvl->iOff==0 ){
    assert( pLvl->bEof==0 );
    pLvl->iOff = 1;
    pLvl->iOff += fts5GetVarint32(&pData->p[1], pLvl->iLeafPgno);
    pLvl->iOff += fts5GetVarint(&pData->p[pLvl->iOff], (u64*)&pLvl->iRowid);
    pLvl->iFirstOff = pLvl->iOff;
  }else{
    int iOff;
    for(iOff=pLvl->iOff; iOff<pData->nn; iOff++){
      if( pData->p[iOff] ) break; 
    }

    if( iOff<pData->nn ){
      i64 iVal;
      pLvl->iLeafPgno += (iOff - pLvl->iOff) + 1;
      iOff += fts5GetVarint(&pData->p[iOff], (u64*)&iVal);
      pLvl->iRowid += iVal;
      pLvl->iOff = iOff;
    }else{
      pLvl->bEof = 1;

static i64 fts5DlidxIterRowid(Fts5DlidxIter *pIter){
  return pIter->aLvl[0].iRowid;
}
static int fts5DlidxIterPgno(Fts5DlidxIter *pIter){
  return pIter->aLvl[0].iLeafPgno;
}






/*
** 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 */
){
  Fts5Data *pLeaf;
  Fts5StructureSegment *pSeg = pIter->pSeg;
  fts5DataRelease(pIter->pLeaf);
  pIter->iLeafPgno++;
  if( pIter->pNextLeaf ){

    pIter->pLeaf = pIter->pNextLeaf;
    pIter->pNextLeaf = 0;
  }else if( pIter->iLeafPgno<=pSeg->pgnoLast ){
    pIter->pLeaf = fts5DataRead(p, 
        FTS5_SEGMENT_ROWID(pSeg->iSegid, pIter->iLeafPgno)
    );
  }else{
    pIter->pLeaf = 0;
  }
  pLeaf = pIter->pLeaf;

  if( pLeaf ){
    pIter->iPgidxOff = pLeaf->szLeaf;
    if( fts5LeafIsTermless(pLeaf) ){
      pIter->iEndofDoclist = pLeaf->nn+1;
    }else{
      pIter->iPgidxOff += fts5GetVarint32(&pLeaf->p[pIter->iPgidxOff],
          pIter->iEndofDoclist
      );
    }
  }
}

/*
** Argument p points to a buffer containing a varint to be interpreted as a
** position list size field. Read the varint and return the number of bytes
** read. Before returning, set *pnSz to the number of bytes in the position

**
** Leave Fts5SegIter.iLeafOffset pointing to the first byte of the 
** position list content (if any).
*/
static void fts5SegIterLoadNPos(Fts5Index *p, Fts5SegIter *pIter){
  if( p->rc==SQLITE_OK ){
    int iOff = pIter->iLeafOffset;  /* Offset to read at */
    ASSERT_SZLEAF_OK(pIter->pLeaf);
    if( iOff>=pIter->pLeaf->szLeaf ){
      p->rc = FTS5_CORRUPT;
    }else{
      const u8 *a = &pIter->pLeaf->p[iOff];
      pIter->iLeafOffset += fts5GetPoslistSize(a, &pIter->nPos, &pIter->bDel);
    }
  }
}

static void fts5SegIterLoadRowid(Fts5Index *p, Fts5SegIter *pIter){
  u8 *a = pIter->pLeaf->p;        /* Buffer to read data from */
  int iOff = pIter->iLeafOffset;

  ASSERT_SZLEAF_OK(pIter->pLeaf);
  if( iOff>=pIter->pLeaf->szLeaf ){
    fts5SegIterNextPage(p, pIter);
    if( pIter->pLeaf==0 ){
      if( p->rc==SQLITE_OK ) p->rc = FTS5_CORRUPT;
      return;
    }
    iOff = 4;
    a = pIter->pLeaf->p;

  iOff += fts5GetVarint32(&a[iOff], nNew);
  pIter->term.n = nKeep;
  fts5BufferAppendBlob(&p->rc, &pIter->term, nNew, &a[iOff]);
  iOff += nNew;
  pIter->iTermLeafOffset = iOff;
  pIter->iTermLeafPgno = pIter->iLeafPgno;
  pIter->iLeafOffset = iOff;

  if( pIter->iPgidxOff>=pIter->pLeaf->nn ){
    pIter->iEndofDoclist = pIter->pLeaf->nn+1;
  }else{
    int nExtra;
    pIter->iPgidxOff += fts5GetVarint32(&a[pIter->iPgidxOff], nExtra);
    pIter->iEndofDoclist += nExtra;
  }

  fts5SegIterLoadRowid(p, pIter);
}

/*
** Initialize the iterator object pIter to iterate through the entries in
** segment pSeg. The iterator is left pointing to the first entry when 

    memset(pIter, 0, sizeof(*pIter));
    pIter->pSeg = pSeg;
    pIter->iLeafPgno = pSeg->pgnoFirst-1;
    fts5SegIterNextPage(p, pIter);
  }

  if( p->rc==SQLITE_OK ){

    pIter->iLeafOffset = 4;
    assert_nc( pIter->pLeaf->nn>4 );
    assert( fts5LeafFirstTermOff(pIter->pLeaf)==4 );
    pIter->iPgidxOff = pIter->pLeaf->szLeaf+1;
    fts5SegIterLoadTerm(p, pIter, 0);
    fts5SegIterLoadNPos(p, pIter);
  }
}

/*
** This function is only ever called on iterators created by calls to

** This function advances the iterator so that it points to the last 
** relevant rowid on the page and, if necessary, initializes the 
** aRowidOffset[] and iRowidOffset variables. At this point the iterator
** is in its regular state - Fts5SegIter.iLeafOffset points to the first
** byte of the position list content associated with said rowid.
*/
static void fts5SegIterReverseInitPage(Fts5Index *p, Fts5SegIter *pIter){
  int n = pIter->pLeaf->szLeaf;
  int i = pIter->iLeafOffset;
  u8 *a = pIter->pLeaf->p;
  int iRowidOffset = 0;

  if( n>pIter->iEndofDoclist ){
    n = pIter->iEndofDoclist;
  }

  ASSERT_SZLEAF_OK(pIter->pLeaf);
  while( 1 ){
    i64 iDelta = 0;
    int nPos;
    int bDummy;

    i += fts5GetPoslistSize(&a[i], &nPos, &bDummy);
    i += nPos;
    if( i>=n ) break;
    i += fts5GetVarint(&a[i], (u64*)&iDelta);

    pIter->iRowid += iDelta;

    if( iRowidOffset>=pIter->nRowidOffset ){
      int nNew = pIter->nRowidOffset + 8;
      int *aNew = (int*)sqlite3_realloc(pIter->aRowidOffset, nNew*sizeof(int));
      if( aNew==0 ){
        p->rc = SQLITE_NOMEM;

  fts5DataRelease(pIter->pLeaf);
  pIter->pLeaf = 0;
  while( p->rc==SQLITE_OK && pIter->iLeafPgno>pIter->iTermLeafPgno ){
    Fts5Data *pNew;
    pIter->iLeafPgno--;
    pNew = fts5DataRead(p, FTS5_SEGMENT_ROWID(
          pIter->pSeg->iSegid, pIter->iLeafPgno
    ));
    if( pNew ){
      /* iTermLeafOffset may be equal to szLeaf if the term is the last
      ** thing on the page - i.e. the first rowid is on the following page.
      ** In this case leaf pIter->pLeaf==0, this iterator is at EOF. */
      if( pIter->iLeafPgno==pIter->iTermLeafPgno 
       && pIter->iTermLeafOffset<pNew->szLeaf 
      ){
        pIter->pLeaf = pNew;
        pIter->iLeafOffset = pIter->iTermLeafOffset;

      }else{
        int iRowidOff;
        iRowidOff = fts5LeafFirstRowidOff(pNew);
        if( iRowidOff ){
          pIter->pLeaf = pNew;
          pIter->iLeafOffset = iRowidOff;
        }
      }

      if( pIter->pLeaf ){
        u8 *a = &pIter->pLeaf->p[pIter->iLeafOffset];
        pIter->iLeafOffset += fts5GetVarint(a, (u64*)&pIter->iRowid);
        break;
      }else{
        fts5DataRelease(pNew);
      }
    }
  }

  if( pIter->pLeaf ){
    pIter->iEndofDoclist = pIter->pLeaf->nn+1;
    fts5SegIterReverseInitPage(p, pIter);
  }
}

/*
** Return true if the iterator passed as the second argument currently
** points to a delete marker. A delete marker is an entry with a 0 byte

      Fts5Data *pLeaf = pIter->pLeaf;
      int iOff;
      int bNewTerm = 0;
      int nKeep = 0;

      /* Search for the end of the position list within the current page. */
      u8 *a = pLeaf->p;
      int n = pLeaf->szLeaf;

      ASSERT_SZLEAF_OK(pLeaf);
      iOff = pIter->iLeafOffset + pIter->nPos;

      if( iOff<n ){
        /* The next entry is on the current page. */


        assert_nc( iOff<=pIter->iEndofDoclist );
        if( iOff>=pIter->iEndofDoclist ){
          bNewTerm = 1;
          if( iOff!=fts5LeafFirstTermOff(pLeaf) ){



            iOff += fts5GetVarint32(&a[iOff], nKeep);
          }
        }else{
          u64 iDelta;
          iOff += sqlite3Fts5GetVarint(&a[iOff], &iDelta);
          pIter->iRowid += iDelta;
          assert_nc( iDelta>0 );
        }
        pIter->iLeafOffset = iOff;

      }else if( pIter->pSeg==0 ){
        const u8 *pList = 0;
        const char *zTerm = 0;
        int nList = 0;
        if( 0==(pIter->flags & FTS5_SEGITER_ONETERM) ){
          sqlite3Fts5HashScanNext(p->pHash);
          sqlite3Fts5HashScanEntry(p->pHash, &zTerm, &pList, &nList);
        }
        if( pList==0 ){
          fts5DataRelease(pIter->pLeaf);
          pIter->pLeaf = 0;
        }else{
          pIter->pLeaf->p = (u8*)pList;
          pIter->pLeaf->nn = nList;
          pIter->pLeaf->szLeaf = nList;
          pIter->iEndofDoclist = nList+1;
          sqlite3Fts5BufferSet(&p->rc, &pIter->term, strlen(zTerm), (u8*)zTerm);
          pIter->iLeafOffset = fts5GetVarint(pList, (u64*)&pIter->iRowid);
        }
      }else{
        iOff = 0;
        /* Next entry is not on the current page */
        while( iOff==0 ){
          fts5SegIterNextPage(p, pIter);
          pLeaf = pIter->pLeaf;
          if( pLeaf==0 ) break;
          ASSERT_SZLEAF_OK(pLeaf);
          if( (iOff = fts5LeafFirstRowidOff(pLeaf)) && iOff<pLeaf->szLeaf ){
            iOff += sqlite3Fts5GetVarint(&pLeaf->p[iOff], (u64*)&pIter->iRowid);
            pIter->iLeafOffset = iOff;

            if( pLeaf->nn>pLeaf->szLeaf ){
              pIter->iPgidxOff = pLeaf->szLeaf + fts5GetVarint32(
                  &pLeaf->p[pLeaf->szLeaf], pIter->iEndofDoclist
              );
            }

          }
          else if( pLeaf->nn>pLeaf->szLeaf ){
            pIter->iPgidxOff = pLeaf->szLeaf + fts5GetVarint32(
                &pLeaf->p[pLeaf->szLeaf], iOff
            );
            pIter->iLeafOffset = iOff;
            pIter->iEndofDoclist = iOff;
            bNewTerm = 1;
          }
          if( iOff>=pLeaf->szLeaf ){
            p->rc = FTS5_CORRUPT;
            return;
          }
        }
      }

      /* Check if the iterator is now at EOF. If so, return early. */

  Fts5DlidxIter *pDlidx = pIter->pDlidx;
  Fts5Data *pLast = 0;
  int pgnoLast = 0;

  if( pDlidx ){
    int iSegid = pIter->pSeg->iSegid;
    pgnoLast = fts5DlidxIterPgno(pDlidx);
    pLast = fts5DataRead(p, FTS5_SEGMENT_ROWID(iSegid, pgnoLast));
  }else{

    Fts5Data *pLeaf = pIter->pLeaf;         /* Current leaf data */

    /* Currently, Fts5SegIter.iLeafOffset points to the first byte of
    ** position-list content for the current rowid. Back it up so that it
    ** points to the start of the position-list size field. */
    pIter->iLeafOffset -= sqlite3Fts5GetVarintLen(pIter->nPos*2+pIter->bDel);





















    /* If this condition is true then the largest rowid for the current
    ** term may not be stored on the current page. So search forward to
    ** see where said rowid really is.  */
    if( pIter->iEndofDoclist>=pLeaf->szLeaf ){
      int pgno;
      Fts5StructureSegment *pSeg = pIter->pSeg;

      /* The last rowid in the doclist may not be on the current page. Search
      ** forward to find the page containing the last rowid.  */
      for(pgno=pIter->iLeafPgno+1; !p->rc && pgno<=pSeg->pgnoLast; pgno++){
        i64 iAbs = FTS5_SEGMENT_ROWID(pSeg->iSegid, pgno);
        Fts5Data *pNew = fts5DataRead(p, iAbs);
        if( pNew ){
          int iRowid, bTermless;
          iRowid = fts5LeafFirstRowidOff(pNew);
          bTermless = fts5LeafIsTermless(pNew);
          if( iRowid ){
            SWAPVAL(Fts5Data*, pNew, pLast);
            pgnoLast = pgno;
          }
          fts5DataRelease(pNew);
          if( bTermless==0 ) break;
        }
      }
    }
  }

  /* If pLast is NULL at this point, then the last rowid for this doclist
  ** lies on the page currently indicated by the iterator. In this case 
  ** pIter->iLeafOffset is already set to point to the position-list size
  ** field associated with the first relevant rowid on the page.
  **
  ** Or, if pLast is non-NULL, then it is the page that contains the last
  ** rowid. In this case configure the iterator so that it points to the
  ** first rowid on this page.
  */
  if( pLast ){

    int iOff;
    fts5DataRelease(pIter->pLeaf);
    pIter->pLeaf = pLast;
    pIter->iLeafPgno = pgnoLast;
    iOff = fts5LeafFirstRowidOff(pLast);
    iOff += fts5GetVarint(&pLast->p[iOff], (u64*)&pIter->iRowid);
    pIter->iLeafOffset = iOff;

    if( fts5LeafIsTermless(pLast) ){
      pIter->iEndofDoclist = pLast->nn+1;
    }else{
      pIter->iEndofDoclist = fts5LeafFirstTermOff(pLast);
    }

  }

  fts5SegIterReverseInitPage(p, pIter);
}

/*
** Iterator pIter currently points to the first rowid of a doclist.

  assert( pIter->flags & FTS5_SEGITER_ONETERM );
  assert( pIter->pDlidx==0 );

  /* Check if the current doclist ends on this page. If it does, return
  ** early without loading the doclist-index (as it belongs to a different
  ** term. */
  if( pIter->iTermLeafPgno==pIter->iLeafPgno 

   && pIter->iEndofDoclist<pLeaf->szLeaf 



  ){


    return;



  }


  pIter->pDlidx = fts5DlidxIterInit(p, bRev, iSeg, pIter->iTermLeafPgno);
}


















































































































#define fts5IndexGetVarint32(a, iOff, nVal) {     \
  nVal = (a)[iOff++];                             \
  if( nVal & 0x80 ){                              \
    iOff--;                                       \
    iOff += fts5GetVarint32(&(a)[iOff], nVal);    \
  }                                               \
}

#define fts5IndexSkipVarint(a, iOff) {            \
  int iEnd = iOff+9;                              \
  while( (a[iOff++] & 0x80) && iOff<iEnd );       \
}

  Fts5Index *p,                   /* Leave any error code here */
  int bGe,                        /* True for a >= search */
  Fts5SegIter *pIter,             /* Iterator to seek */
  const u8 *pTerm, int nTerm      /* Term to search for */
){
  int iOff;
  const u8 *a = pIter->pLeaf->p;
  int szLeaf = pIter->pLeaf->szLeaf;
  int n = pIter->pLeaf->nn;

  int nMatch = 0;
  int nKeep = 0;
  int nNew = 0;
  int iTermOff;
  int iPgidx;                     /* Current offset in pgidx */
  int bEndOfPage = 0;

  assert( p->rc==SQLITE_OK );


  iPgidx = szLeaf;
  iPgidx += fts5GetVarint32(&a[iPgidx], iTermOff);
  iOff = iTermOff;




  while( 1 ){



    /* Figure out how many new bytes are in this term */
    fts5IndexGetVarint32(a, iOff, nNew);

    if( nKeep<nMatch ){
      goto search_failed;
    }

    assert( nKeep>=nMatch );
    if( nKeep==nMatch ){
      int nCmp;
      int i;
      nCmp = MIN(nNew, nTerm-nMatch);
      for(i=0; i<nCmp; i++){
        if( a[iOff+i]!=pTerm[nMatch+i] ) break;
      }
      nMatch += i;

      if( nTerm==nMatch ){
        if( i==nNew ){
          goto search_success;
        }else{
          goto search_failed;
        }
      }else if( i<nNew && a[iOff+i]>pTerm[nMatch] ){
        goto search_failed;
      }
    }


    if( iPgidx>=n ){
      bEndOfPage = 1;
      break;

    }




    iPgidx += fts5GetVarint32(&a[iPgidx], nKeep);
    iTermOff += nKeep;

    iOff = iTermOff;










    /* Read the nKeep field of the next term. */
    fts5IndexGetVarint32(a, iOff, nKeep);
  }

 search_failed:
  if( bGe==0 ){
    fts5DataRelease(pIter->pLeaf);
    pIter->pLeaf = 0;
    return;
  }else if( bEndOfPage ){
    do {
      fts5SegIterNextPage(p, pIter);
      if( pIter->pLeaf==0 ) return;
      a = pIter->pLeaf->p;
      if( fts5LeafIsTermless(pIter->pLeaf)==0 ){
        fts5GetVarint32(&pIter->pLeaf->p[pIter->pLeaf->szLeaf], iOff);
        if( iOff<4 || iOff>=pIter->pLeaf->szLeaf ){
          p->rc = FTS5_CORRUPT;
        }else{
          nKeep = 0;
          iOff += fts5GetVarint32(&a[iOff], nNew);
          break;
        }
      }
    }while( 1 );
  }

 search_success:

  pIter->iLeafOffset = iOff + nNew;
  pIter->iTermLeafOffset = pIter->iLeafOffset;
  pIter->iTermLeafPgno = pIter->iLeafPgno;

  fts5BufferSet(&p->rc, &pIter->term, nKeep, pTerm);
  fts5BufferAppendBlob(&p->rc, &pIter->term, nNew, &a[iOff]);

  if( iPgidx>=n ){
    pIter->iEndofDoclist = pIter->pLeaf->nn+1;
  }else{
    int nExtra;
    iPgidx += fts5GetVarint32(&a[iPgidx], nExtra);
    pIter->iEndofDoclist = iTermOff + nExtra;
  }
  pIter->iPgidxOff = iPgidx;

  fts5SegIterLoadRowid(p, pIter);
  fts5SegIterLoadNPos(p, pIter);
}

/*
** Initialize the object pIter to point to term pTerm/nTerm within segment
** pSeg. If there is no such term in the index, the iterator is set to EOF.

  if( pList ){
    Fts5Data *pLeaf;
    sqlite3Fts5BufferSet(&p->rc, &pIter->term, n, z);
    pLeaf = fts5IdxMalloc(p, sizeof(Fts5Data));
    if( pLeaf==0 ) return;
    pLeaf->p = (u8*)pList;
    pLeaf->nn = pLeaf->szLeaf = nList;
    pIter->pLeaf = pLeaf;
    pIter->iLeafOffset = fts5GetVarint(pLeaf->p, (u64*)&pIter->iRowid);
    pIter->iEndofDoclist = pLeaf->nn+1;

    if( flags & FTS5INDEX_QUERY_DESC ){
      pIter->flags |= FTS5_SEGITER_REVERSE;
      fts5SegIterReverseInitPage(p, pIter);
    }else{
      fts5SegIterLoadNPos(p, pIter);
    }

    pIter->iLeafPgno = iLeafPgno-1;
    fts5SegIterNextPage(p, pIter);
    assert( p->rc!=SQLITE_OK || pIter->iLeafPgno==iLeafPgno );

    if( p->rc==SQLITE_OK ){
      int iOff;
      u8 *a = pIter->pLeaf->p;
      int n = pIter->pLeaf->szLeaf;

      iOff = fts5LeafFirstRowidOff(pIter->pLeaf);
      if( iOff<4 || iOff>=n ){
        p->rc = FTS5_CORRUPT;
      }else{
        iOff += fts5GetVarint(&a[iOff], (u64*)&pIter->iRowid);
        pIter->iLeafOffset = iOff;
        fts5SegIterLoadNPos(p, pIter);
      }

    if( iLeafPgno<pIter->iLeafPgno ){
      pIter->iLeafPgno = iLeafPgno+1;
      fts5SegIterReverseNewPage(p, pIter);
      bMove = 0;
    }
  }


  do{
    if( bMove ) fts5SegIterNext(p, pIter, 0);
    if( pIter->pLeaf==0 ) break;
    if( bRev==0 && pIter->iRowid>=iMatch ) break;
    if( bRev!=0 && pIter->iRowid<=iMatch ) break;
    bMove = 1;
  }while( p->rc==SQLITE_OK );
}


/*
** Free the iterator object passed as the second argument.
*/
static void fts5MultiIterFree(Fts5Index *p, Fts5IndexIter *pIter){

){
  Fts5IndexIter *pNew;
  pNew = fts5MultiIterAlloc(p, 2);
  if( pNew ){
    Fts5SegIter *pIter = &pNew->aSeg[1];

    pIter->flags = FTS5_SEGITER_ONETERM;
    if( pData->szLeaf>0 ){
      pIter->pLeaf = pData;
      pIter->iLeafOffset = fts5GetVarint(pData->p, (u64*)&pIter->iRowid);
      pIter->iEndofDoclist = pData->nn;
      pNew->aFirst[1].iFirst = 1;
      if( bDesc ){
        pNew->bRev = 1;
        pIter->flags |= FTS5_SEGITER_REVERSE;
        fts5SegIterReverseInitPage(p, pIter);
      }else{
        fts5SegIterLoadNPos(p, pIter);

  Fts5SegIter *pSeg,              /* Poslist of this iterator */
  void *pCtx,                     /* Context pointer for xChunk callback */
  void (*xChunk)(Fts5Index*, void*, const u8*, int)
){
  int nRem = pSeg->nPos;          /* Number of bytes still to come */
  Fts5Data *pData = 0;
  u8 *pChunk = &pSeg->pLeaf->p[pSeg->iLeafOffset];
  int nChunk = MIN(nRem, pSeg->pLeaf->szLeaf - pSeg->iLeafOffset);
  int pgno = pSeg->iLeafPgno;
  int pgnoSave = 0;

  if( (pSeg->flags & FTS5_SEGITER_REVERSE)==0 ){
    pgnoSave = pgno+1;
  }

  while( 1 ){
    xChunk(p, pCtx, pChunk, nChunk);
    nRem -= nChunk;
    fts5DataRelease(pData);
    if( nRem<=0 ){
      break;
    }else{
      pgno++;
      pData = fts5DataRead(p, FTS5_SEGMENT_ROWID(pSeg->pSeg->iSegid, pgno));
      if( pData==0 ) break;
      pChunk = &pData->p[4];
      nChunk = MIN(nRem, pData->szLeaf - 4);
      if( pgno==pgnoSave ){
        assert( pSeg->pNextLeaf==0 );
        pSeg->pNextLeaf = pData;
        pData = 0;
      }
    }
  }

}

static void fts5WriteFlushLeaf(Fts5Index *p, Fts5SegWriter *pWriter){
  static const u8 zero[] = { 0x00, 0x00, 0x00, 0x00 };
  Fts5PageWriter *pPage = &pWriter->writer;
  i64 iRowid;

  assert( (pPage->pgidx.n==0)==(pWriter->bFirstTermInPage) );

  /* Set the szLeaf header field. */
  assert( 0==fts5GetU16(&pPage->buf.p[2]) );
  fts5PutU16(&pPage->buf.p[2], pPage->buf.n);

  if( pWriter->bFirstTermInPage ){
    /* No term was written to this page. */
    assert( pPage->pgidx.n==0 );
    fts5WriteBtreeNoTerm(p, pWriter);
  }else{
    /* Append the pgidx to the page buffer. Set the szLeaf header field. */
    fts5BufferAppendBlob(&p->rc, &pPage->buf, pPage->pgidx.n, pPage->pgidx.p);
  }

  /* Write the page out to disk */
  iRowid = FTS5_SEGMENT_ROWID(pWriter->iSegid, pPage->pgno);
  fts5DataWrite(p, iRowid, pPage->buf.p, pPage->buf.n);

  /* Initialize the next page. */
  fts5BufferZero(&pPage->buf);
  fts5BufferZero(&pPage->pgidx);
  fts5BufferAppendBlob(&p->rc, &pPage->buf, 4, zero);
  pPage->iPrevPgidx = 0;
  pPage->pgno++;

  /* Increase the leaves written counter */
  pWriter->nLeafWritten++;

  /* The new leaf holds no terms or rowids */
  pWriter->bFirstTermInPage = 1;

static void fts5WriteAppendTerm(
  Fts5Index *p, 
  Fts5SegWriter *pWriter,
  int nTerm, const u8 *pTerm 
){
  int nPrefix;                    /* Bytes of prefix compression for term */
  Fts5PageWriter *pPage = &pWriter->writer;
  Fts5Buffer *pPgidx = &pWriter->writer.pgidx;

  assert( p->rc==SQLITE_OK );
  assert( pPage->buf.n>=4 );
  assert( pPage->buf.n>4 || pWriter->bFirstTermInPage );

  /* If the current leaf page is full, flush it to disk. */
  if( (pPage->buf.n + pPgidx->n + nTerm + 2)>=p->pConfig->pgsz ){
    if( pPage->buf.n>4 ){


      fts5WriteFlushLeaf(p, pWriter);
    }
    fts5BufferGrow(&p->rc, &pPage->buf, nTerm+FTS5_DATA_PADDING);

  }
  
  /* TODO1: Updating pgidx here. */
  pPgidx->n += sqlite3Fts5PutVarint(
      &pPgidx->p[pPgidx->n], pPage->buf.n - pPage->iPrevPgidx
  );
  pPage->iPrevPgidx = pPage->buf.n;
#if 0
  fts5PutU16(&pPgidx->p[pPgidx->n], pPage->buf.n);
  pPgidx->n += 2;
#endif

  if( pWriter->bFirstTermInPage ){



    nPrefix = 0;
    if( pPage->pgno!=1 ){
      /* This is the first term on a leaf that is not the leftmost leaf in
      ** the segment b-tree. In this case it is necessary to add a term to
      ** the b-tree hierarchy that is (a) larger than the largest term 
      ** already written to the segment and (b) smaller than or equal to
      ** this term. In other words, a prefix of (pTerm/nTerm) that is one

  pWriter->bFirstTermInPage = 0;

  pWriter->bFirstRowidInPage = 0;
  pWriter->bFirstRowidInDoclist = 1;

  assert( p->rc || (pWriter->nDlidx>0 && pWriter->aDlidx[0].buf.n==0) );
  pWriter->aDlidx[0].pgno = pPage->pgno;





}

/*
** Append a rowid and position-list size field to the writers output. 
*/
static void fts5WriteAppendRowid(
  Fts5Index *p, 
  Fts5SegWriter *pWriter,
  i64 iRowid,
  int nPos
){
  if( p->rc==SQLITE_OK ){
    Fts5PageWriter *pPage = &pWriter->writer;

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

    /* If this is to be the first rowid written to the page, set the 
    ** rowid-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);

      fts5BufferAppendVarint(&p->rc, &pPage->buf, iRowid - pWriter->iPrevRowid);
    }
    pWriter->iPrevRowid = iRowid;
    pWriter->bFirstRowidInDoclist = 0;
    pWriter->bFirstRowidInPage = 0;

    fts5BufferAppendVarint(&p->rc, &pPage->buf, nPos);




  }
}

static void fts5WriteAppendPoslistData(
  Fts5Index *p, 
  Fts5SegWriter *pWriter, 
  const u8 *aData, 
  int nData
){
  Fts5PageWriter *pPage = &pWriter->writer;
  const u8 *a = aData;
  int n = nData;
  
  assert( p->pConfig->pgsz>0 );
  while( p->rc==SQLITE_OK 
     && (pPage->buf.n + pPage->pgidx.n + n)>=p->pConfig->pgsz 
  ){
    int nReq = p->pConfig->pgsz - pPage->buf.n - pPage->pgidx.n;
    int nCopy = 0;
    while( nCopy<nReq ){
      i64 dummy;
      nCopy += fts5GetVarint(&a[nCopy], (u64*)&dummy);
    }
    fts5BufferAppendBlob(&p->rc, &pPage->buf, nCopy, a);
    a += nCopy;
    n -= nCopy;
    fts5WriteFlushLeaf(p, pWriter);
  }
  if( n>0 ){
    fts5BufferAppendBlob(&p->rc, &pPage->buf, n, a);
  }
}





/*
** Flush any data cached by the writer object to the database. Free any
** allocations associated with the writer.
*/
static void fts5WriteFinish(
  Fts5Index *p, 
  Fts5SegWriter *pWriter,         /* Writer object */

  int *pnLeaf                     /* OUT: Number of leaf pages in b-tree */
){
  int i;
  Fts5PageWriter *pLeaf = &pWriter->writer;
  if( p->rc==SQLITE_OK ){
    assert( pLeaf->pgno>=1 );



    if( pLeaf->buf.n>4 ){
      fts5WriteFlushLeaf(p, pWriter);
    }
    *pnLeaf = pLeaf->pgno-1;

    fts5WriteFlushBtree(p, pWriter);


  }
  fts5BufferFree(&pLeaf->term);
  fts5BufferFree(&pLeaf->buf);
  fts5BufferFree(&pLeaf->pgidx);
  fts5BufferFree(&pWriter->btterm);

  for(i=0; i<pWriter->nDlidx; i++){
    sqlite3Fts5BufferFree(&pWriter->aDlidx[i].buf);
  }
  sqlite3_free(pWriter->aDlidx);
}

static void fts5WriteInit(
  Fts5Index *p, 
  Fts5SegWriter *pWriter, 
  int iSegid
){
  const int nBuffer = p->pConfig->pgsz + FTS5_DATA_PADDING;

  memset(pWriter, 0, sizeof(Fts5SegWriter));
  pWriter->iSegid = iSegid;

  fts5WriteDlidxGrow(p, pWriter, 1);
  pWriter->writer.pgno = 1;
  pWriter->bFirstTermInPage = 1;
  pWriter->iBtPage = 1;

  /* Grow the two buffers to pgsz + padding bytes in size. */
  fts5BufferGrow(&p->rc, &pWriter->writer.pgidx, nBuffer);
  fts5BufferGrow(&p->rc, &pWriter->writer.buf, nBuffer);

  if( p->pIdxWriter==0 ){
    Fts5Config *pConfig = p->pConfig;
    fts5IndexPrepareStmt(p, &p->pIdxWriter, sqlite3_mprintf(
          "INSERT INTO '%q'.'%q_idx'(segid,term,pgno) VALUES(?,?,?)", 
          pConfig->zDb, pConfig->zName
    ));
  }

  if( p->rc==SQLITE_OK ){
    /* Initialize the 4-byte leaf-page header to 0x00. */
    memset(pWriter->writer.buf.p, 0, 4);
    pWriter->writer.buf.n = 4;

    /* Bind the current output segment id to the index-writer. This is an
    ** optimization over binding the same value over and over as rows are
    ** inserted into %_idx by the current writer.  */
    sqlite3_bind_int(p->pIdxWriter, 1, pWriter->iSegid);
  }
}

/*
** Iterator pIter was used to iterate through the input segments of on an
** incremental merge operation. This function is called if the incremental

      pSeg->pSeg->pgnoLast = 0;
      pSeg->pSeg->pgnoFirst = 0;
    }else{
      int iOff = pSeg->iTermLeafOffset;     /* Offset on new first leaf page */
      i64 iLeafRowid;
      Fts5Data *pData;
      int iId = pSeg->pSeg->iSegid;
      u8 aHdr[4] = {0x00, 0x00, 0x00, 0x00};

      iLeafRowid = FTS5_SEGMENT_ROWID(iId, pSeg->iTermLeafPgno);
      pData = fts5DataRead(p, iLeafRowid);
      if( pData ){
        fts5BufferZero(&buf);
        fts5BufferGrow(&p->rc, &buf, pData->nn);
        fts5BufferAppendBlob(&p->rc, &buf, sizeof(aHdr), aHdr);
        fts5BufferAppendVarint(&p->rc, &buf, pSeg->term.n);
        fts5BufferAppendBlob(&p->rc, &buf, pSeg->term.n, pSeg->term.p);
        fts5BufferAppendBlob(&p->rc, &buf, pData->szLeaf-iOff, &pData->p[iOff]);
        if( p->rc==SQLITE_OK ){
          /* Set the szLeaf field */
          fts5PutU16(&buf.p[2], buf.n);
        }

        /* Set up the new page-index array */
        fts5BufferAppendVarint(&p->rc, &buf, 4);
        if( pSeg->iLeafPgno==pSeg->iTermLeafPgno 
         && pSeg->iEndofDoclist<pData->szLeaf 
        ){
          int nDiff = pData->szLeaf - pSeg->iEndofDoclist;
          fts5BufferAppendVarint(&p->rc, &buf, buf.n - 1 - nDiff - 4);
          fts5BufferAppendBlob(&p->rc, &buf, 
              pData->nn - pSeg->iPgidxOff, &pData->p[pSeg->iPgidxOff]
          );
        }

        fts5DataRelease(pData);
        pSeg->pSeg->pgnoFirst = pSeg->iTermLeafPgno;
        fts5DataDelete(p, FTS5_SEGMENT_ROWID(iId, 1), iLeafRowid);
        fts5DataWrite(p, iLeafRowid, buf.p, buf.n);
      }
    }
  }
  fts5BufferFree(&buf);
}

  Fts5StructureLevel *pLvlOut;
  Fts5IndexIter *pIter = 0;       /* Iterator to read input data */
  int nRem = pnRem ? *pnRem : 0;  /* Output leaf pages left to write */
  int nInput;                     /* Number of input segments */
  Fts5SegWriter writer;           /* Writer object */
  Fts5StructureSegment *pSeg;     /* Output segment */
  Fts5Buffer term;

  int bOldest;                    /* True if the output segment is the oldest */

  assert( iLvl<pStruct->nLevel );
  assert( pLvl->nMerge<=pLvl->nSeg );

  memset(&writer, 0, sizeof(Fts5SegWriter));
  memset(&term, 0, sizeof(Fts5Buffer));

    pTerm = fts5MultiIterTerm(pIter, &nTerm);
    if( nTerm!=term.n || memcmp(pTerm, term.p, nTerm) ){
      if( pnRem && writer.nLeafWritten>nRem ){
        break;
      }

      /* This is a new term. Append a term to the output segment. */



      fts5WriteAppendTerm(p, &writer, nTerm, pTerm);
      fts5BufferSet(&p->rc, &term, nTerm, pTerm);

    }

    /* Append the rowid to the output */
    /* WRITEPOSLISTSIZE */
    nPos = pSegIter->nPos*2 + pSegIter->bDel;
    fts5WriteAppendRowid(p, &writer, fts5MultiIterRowid(pIter), nPos);

    /* Append the position-list data to the output */
    fts5ChunkIterate(p, pSegIter, (void*)&writer, fts5MergeChunkCallback);
  }

  /* Flush the last leaf page to disk. Set the output segment b-tree height
  ** and last leaf page number at the same time.  */
  fts5WriteFinish(p, &writer, &pSeg->pgnoLast);

  if( fts5MultiIterEof(p, pIter) ){
    int i;

    /* Remove the redundant segments from the %_data table */
    for(i=0; i<nInput; i++){
      fts5DataRemoveSegment(p, pLvl->aSeg[i].iSegid);

  const int nCrisis = p->pConfig->nCrisisMerge;
  Fts5Structure *pStruct = *ppStruct;
  int iLvl = 0;

  assert( p->rc!=SQLITE_OK || pStruct->nLevel>0 );
  while( p->rc==SQLITE_OK && pStruct->aLevel[iLvl].nSeg>=nCrisis ){
    fts5IndexMergeLevel(p, &pStruct, iLvl, 0);
    assert( p->rc!=SQLITE_OK || pStruct->nLevel>(iLvl+1) );
    fts5StructurePromote(p, iLvl+1, pStruct);
    iLvl++;
  }
  *ppStruct = pStruct;
}

static int fts5IndexReturn(Fts5Index *p){

** 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;
  u32 dummy;
  ret = fts5GetVarint32(aBuf, dummy);
  if( ret<nMax ){
    while( 1 ){
      int i = fts5GetVarint32(&aBuf[ret], dummy);
      if( (ret + i) > nMax ) break;
      ret += i;
    }
  }
  return ret;
}

#define fts5BufferSafeAppendBlob(pBuf, pBlob, nBlob) { \
  assert( pBuf->nSpace>=(pBuf->n+nBlob) );             \
  memcpy(&pBuf->p[pBuf->n], pBlob, nBlob);             \

  pStruct = fts5StructureRead(p);
  iSegid = fts5AllocateSegid(p, pStruct);

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

    Fts5StructureSegment *pSeg;   /* New segment within pStruct */

    Fts5Buffer *pBuf;             /* Buffer in which to assemble leaf page */

    Fts5Buffer *pPgidx;           /* Buffer in which to assemble pgidx */

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




    pBuf = &writer.writer.buf;
    pPgidx = &writer.writer.pgidx;

    /* fts5WriteInit() should have initialized the buffers to (most likely)
    ** the maximum space required. */
    assert( p->rc || pBuf->nSpace>=(pgsz + FTS5_DATA_PADDING) );
    assert( p->rc || pPgidx->nSpace>=(pgsz + FTS5_DATA_PADDING) );

    /* Begin scanning through hash table entries. This loop runs once for each
    ** term/doclist currently stored within the hash table. */
    if( p->rc==SQLITE_OK ){


      p->rc = sqlite3Fts5HashScanInit(pHash, 0, 0);
    }
    while( p->rc==SQLITE_OK && 0==sqlite3Fts5HashScanEof(pHash) ){
      const char *zTerm;          /* Buffer containing term */

      const u8 *pDoclist;         /* Pointer to doclist for this term */
      int nDoclist;               /* Size of doclist in bytes */


      /* Write the term for this entry to disk. */
      sqlite3Fts5HashScanEntry(pHash, &zTerm, &pDoclist, &nDoclist);

      fts5WriteAppendTerm(p, &writer, strlen(zTerm), (const u8*)zTerm);














      assert( writer.bFirstRowidInPage==0 );























      if( pgsz>=(pBuf->n + pPgidx->n + nDoclist + 1) ){
        /* The entire doclist will fit on the current leaf. */
        fts5BufferSafeAppendBlob(pBuf, pDoclist, nDoclist);
      }else{
        i64 iRowid = 0;
        i64 iDelta = 0;
        int iOff = 0;



        /* The entire doclist will not fit on this leaf. The following 
        ** loop iterates through the poslists that make up the current 
        ** doclist.  */
        while( p->rc==SQLITE_OK && iOff<nDoclist ){
          int nPos;
          int nCopy;
          int bDummy;

            writer.bFirstRowidInPage = 0;
            fts5WriteDlidxAppend(p, &writer, iRowid);
          }else{
            pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], iDelta);
          }
          assert( pBuf->n<=pBuf->nSpace );

          if( (pBuf->n + pPgidx->n + nCopy) <= pgsz ){
            /* The entire poslist will fit on the current leaf. So copy
            ** it in one go. */
            fts5BufferSafeAppendBlob(pBuf, &pDoclist[iOff], nCopy);
          }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( p->rc==SQLITE_OK ){
              int nSpace = pgsz - pBuf->n - pPgidx->n;
              int n = 0;
              if( (nCopy - iPos)<=nSpace ){
                n = nCopy - iPos;
              }else{
                n = fts5PoslistPrefix(&pPoslist[iPos], nSpace);
              }
              assert( n>0 );
              fts5BufferSafeAppendBlob(pBuf, &pPoslist[iPos], n);
              iPos += n;
              if( (pBuf->n + pPgidx->n)>=pgsz ){
                fts5WriteFlushLeaf(p, &writer);

              }
              if( iPos>=nCopy ) break;
            }
          }
          iOff += nCopy;
        }
      }

      /* TODO2: Doclist terminator written here. */
      /* pBuf->p[pBuf->n++] = '\0'; */
      assert( pBuf->n<=pBuf->nSpace );

      sqlite3Fts5HashScanNext(pHash);
    }
    sqlite3Fts5HashClear(pHash);
    fts5WriteFinish(p, &writer, &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);
    if( p->rc==SQLITE_OK ){
      pSeg = &pStruct->aLevel[0].aSeg[ pStruct->aLevel[0].nSeg++ ];
      pSeg->iSegid = iSegid;

      pSeg->pgnoFirst = 1;
      pSeg->pgnoLast = pgnoLast;
      pStruct->nSegment++;
    }
    fts5StructurePromote(p, 0, pStruct);
  }

}

static void fts5PoslistCallback(
  Fts5Index *p, 
  void *pCtx, 
  const u8 *pChunk, int nChunk
){
  assert_nc( nChunk>=0 );
  if( nChunk>0 ){
    fts5BufferAppendBlob(&p->rc, (Fts5Buffer*)pCtx, nChunk, pChunk);
  }
}

/*
** Iterator pIter currently points to a valid entry (not EOF). This
** function appends the position list data for the current entry to
** buffer pBuf. It does not make a copy of the position-list size
** field.

    for(fts5MultiIterNew(p, pStruct, 1, flags, pToken, nToken, -1, 0, &p1);
        fts5MultiIterEof(p, p1)==0;
        fts5MultiIterNext(p, p1, 0, 0)
    ){
      i64 iRowid = fts5MultiIterRowid(p1);
      int nTerm;
      const u8 *pTerm = fts5MultiIterTerm(p1, &nTerm);
      assert_nc( memcmp(pToken, pTerm, MIN(nToken, nTerm))<=0 );
      if( nTerm<nToken || memcmp(pToken, pTerm, nToken) ) break;

      if( doclist.n>0 && iRowid<=iLastRowid ){
        for(i=0; p->rc==SQLITE_OK && doclist.n; i++){
          assert( i<nBuf );
          if( aBuf[i].n==0 ){
            fts5BufferSwap(&doclist, &aBuf[i]);

      fts5BufferFree(&aBuf[i]);
    }
    fts5MultiIterFree(p, p1);

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

  fts5StructureRelease(pStruct);

/*
** The %_data table is completely empty when this function is called. This
** function populates it with the initial structure objects for each index,
** and the initial version of the "averages" record (a zero-byte blob).
*/
int sqlite3Fts5IndexReinit(Fts5Index *p){
  Fts5Structure s;




  memset(&s, 0, sizeof(Fts5Structure));
  fts5DataWrite(p, FTS5_AVERAGES_ROWID, (const u8*)"", 0);
  fts5StructureWrite(p, &s);

  return fts5IndexReturn(p);
}

/*
** Open a new Fts5Index handle. If the bCreate argument is true, create
** and initialize the underlying %_data table.
**

       || (flags & FTS5INDEX_QUERY_SCAN)==FTS5INDEX_QUERY_SCAN
  );

  if( sqlite3Fts5BufferGrow(&p->rc, &buf, nToken+1)==0 ){
    memcpy(&buf.p[1], pToken, nToken);

#ifdef SQLITE_DEBUG
    /* If the QUERY_TEST_NOIDX flag was specified, then this must be a
    ** prefix-query. Instead of using a prefix-index (if one exists), 
    ** evaluate the prefix query using the main FTS index. This is used
    ** for internal sanity checking by the integrity-check in debug 
    ** mode only.  */
    if( pConfig->bPrefixIndex==0 || (flags & FTS5INDEX_QUERY_TEST_NOIDX) ){
      assert( flags & FTS5INDEX_QUERY_PREFIX );
      iIdx = 1+pConfig->nPrefix;
    }else
#endif
    if( flags & FTS5INDEX_QUERY_PREFIX ){
      int nChar = fts5IndexCharlen(pToken, nToken);
      for(iIdx=1; iIdx<=pConfig->nPrefix; iIdx++){

  int *pn,                        /* OUT: Size of position-list in bytes */
  i64 *piRowid                    /* OUT: Current rowid */
){
  Fts5SegIter *pSeg = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
  assert( pIter->pIndex->rc==SQLITE_OK );
  *piRowid = pSeg->iRowid;
  *pn = pSeg->nPos;
  if( pSeg->iLeafOffset+pSeg->nPos <= pSeg->pLeaf->szLeaf ){
    *pp = &pSeg->pLeaf->p[pSeg->iLeafOffset];
  }else{
    fts5BufferZero(&pIter->poslist);
    fts5SegiterPoslist(pIter->pIndex, pSeg, &pIter->poslist);
    *pp = pIter->poslist.p;
  }
  return fts5IndexReturn(pIter->pIndex);

    Fts5Index *pIndex = pIter->pIndex;
    fts5MultiIterFree(pIter->pIndex, pIter);
    fts5CloseReader(pIndex);
  }
}

/*
** Read and decode the "averages" record from the database. 

**
** Parameter anSize must point to an array of size nCol, where nCol is
** the number of user defined columns in the FTS table.
*/
int sqlite3Fts5IndexGetAverages(Fts5Index *p, i64 *pnRow, i64 *anSize){
  int nCol = p->pConfig->nCol;
  Fts5Data *pData;

  *pnRow = 0;
  memset(anSize, 0, sizeof(i64) * nCol);
  pData = fts5DataRead(p, FTS5_AVERAGES_ROWID);
  if( p->rc==SQLITE_OK && pData->nn ){
    int i = 0;
    int iCol;
    i += fts5GetVarint(&pData->p[i], (u64*)pnRow);
    for(iCol=0; i<pData->nn && iCol<nCol; iCol++){
      i += fts5GetVarint(&pData->p[i], (u64*)&anSize[iCol]);
    }
  }

  fts5DataRelease(pData);
  return fts5IndexReturn(p);
}

/*
** Replace the current "averages" record with the contents of the buffer 
** supplied as the second argument.
*/

    if( rc==SQLITE_OK ){
      int f = flags|FTS5INDEX_QUERY_DESC;
      rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, f, &ck2);
    }
    if( rc==SQLITE_OK && ck1!=ck2 ) rc = FTS5_CORRUPT;

    /* If this is a prefix query, check that the results returned if the
    ** the index is disabled are the same. In both ASC and DESC order. 
    **
    ** This check may only be performed if the hash table is empty. This
    ** is because the hash table only supports a single scan query at
    ** a time, and the multi-iter loop from which this function is called
    ** is already performing such a scan. */
    if( p->nPendingData==0 ){
      if( iIdx>0 && rc==SQLITE_OK ){
        int f = flags|FTS5INDEX_QUERY_TEST_NOIDX;
        ck2 = 0;
        rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, f, &ck2);
        if( rc==SQLITE_OK && ck1!=ck2 ) rc = FTS5_CORRUPT;
      }
      if( iIdx>0 && rc==SQLITE_OK ){
        int f = flags|FTS5INDEX_QUERY_TEST_NOIDX|FTS5INDEX_QUERY_DESC;
        ck2 = 0;
        rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, f, &ck2);
        if( rc==SQLITE_OK && ck1!=ck2 ) rc = FTS5_CORRUPT;
      }
    }

    cksum3 ^= ck1;
    fts5BufferSet(&rc, pPrev, n, (const u8*)z);

    if( rc==SQLITE_OK && cksum3!=expected ){
      rc = FTS5_CORRUPT;

  int iLast
){
  int i;

  /* Now check that the iter.nEmpty leaves following the current leaf
  ** (a) exist and (b) contain no terms. */
  for(i=iFirst; p->rc==SQLITE_OK && i<=iLast; i++){
    Fts5Data *pLeaf = fts5DataRead(p, FTS5_SEGMENT_ROWID(pSeg->iSegid, i));
    if( pLeaf ){
      if( !fts5LeafIsTermless(pLeaf) ) p->rc = FTS5_CORRUPT;
      if( i>=iNoRowid && 0!=fts5LeafFirstRowidOff(pLeaf) ) p->rc = FTS5_CORRUPT;
    }
    fts5DataRelease(pLeaf);
  }
}

static void fts5IntegrityCheckPgidx(Fts5Index *p, Fts5Data *pLeaf){
  int iTermOff = 0;
  int ii;

  Fts5Buffer buf1 = {0,0,0};
  Fts5Buffer buf2 = {0,0,0};

  ii = pLeaf->szLeaf;
  while( ii<pLeaf->nn && p->rc==SQLITE_OK ){
    int res;
    int iOff;
    int nIncr;

    ii += fts5GetVarint32(&pLeaf->p[ii], nIncr);
    iTermOff += nIncr;
    iOff = iTermOff;

    if( iOff>=pLeaf->szLeaf ){
      p->rc = FTS5_CORRUPT;
    }else if( iTermOff==nIncr ){
      int nByte;
      iOff += fts5GetVarint32(&pLeaf->p[iOff], nByte);
      if( (iOff+nByte)>pLeaf->szLeaf ){
        p->rc = FTS5_CORRUPT;
      }else{
        fts5BufferSet(&p->rc, &buf1, nByte, &pLeaf->p[iOff]);
      }
    }else{
      int nKeep, nByte;
      iOff += fts5GetVarint32(&pLeaf->p[iOff], nKeep);
      iOff += fts5GetVarint32(&pLeaf->p[iOff], nByte);
      if( nKeep>buf1.n || (iOff+nByte)>pLeaf->szLeaf ){
        p->rc = FTS5_CORRUPT;
      }else{
        buf1.n = nKeep;
        fts5BufferAppendBlob(&p->rc, &buf1, nByte, &pLeaf->p[iOff]);
      }

      if( p->rc==SQLITE_OK ){
        res = fts5BufferCompare(&buf1, &buf2);
        if( res<=0 ) p->rc = FTS5_CORRUPT;
      }
    }
    fts5BufferSet(&p->rc, &buf2, buf1.n, buf1.p);
  }

  fts5BufferFree(&buf1);
  fts5BufferFree(&buf2);
}

static void fts5IndexIntegrityCheckSegment(
  Fts5Index *p,                   /* FTS5 backend object */
  Fts5StructureSegment *pSeg      /* Segment to check internal consistency */
){
  Fts5Config *pConfig = p->pConfig;
  sqlite3_stmt *pStmt = 0;
  int rc2;
  int iIdxPrevLeaf = pSeg->pgnoFirst-1;
  int iDlidxPrevLeaf = pSeg->pgnoLast;

  if( pSeg->pgnoFirst==0 ) return;

  fts5IndexPrepareStmt(p, &pStmt, sqlite3_mprintf(
      "SELECT segid, term, (pgno>>1), (pgno&1) FROM %Q.'%q_idx' WHERE segid=%d",
      pConfig->zDb, pConfig->zName, pSeg->iSegid
  ));

  /* Iterate through the b-tree hierarchy.  */
  while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
    i64 iRow;                     /* Rowid for this leaf */
    Fts5Data *pLeaf;              /* Data for this leaf */


    int nIdxTerm = sqlite3_column_bytes(pStmt, 1);
    const char *zIdxTerm = (const char*)sqlite3_column_text(pStmt, 1);
    int iIdxLeaf = sqlite3_column_int(pStmt, 2);
    int bIdxDlidx = sqlite3_column_int(pStmt, 3);

    /* If the leaf in question has already been trimmed from the segment, 
    ** ignore this b-tree entry. Otherwise, load it into memory. */
    if( iIdxLeaf<pSeg->pgnoFirst ) continue;
    iRow = FTS5_SEGMENT_ROWID(pSeg->iSegid, iIdxLeaf);
    pLeaf = fts5DataRead(p, iRow);
    if( pLeaf==0 ) break;

    /* Check that the leaf contains at least one term, and that it is equal
    ** to or larger than the split-key in zIdxTerm.  Also check that if there
    ** is also a rowid pointer within the leaf page header, it points to a
    ** location before the term.  */
    if( pLeaf->nn<=pLeaf->szLeaf ){

      p->rc = FTS5_CORRUPT;
    }else{
      int iOff;                   /* Offset of first term on leaf */
      int iRowidOff;              /* Offset of first rowid on leaf */
      int nTerm;                  /* Size of term on leaf in bytes */
      int res;                    /* Comparison of term and split-key */

      iOff = fts5LeafFirstTermOff(pLeaf);
      iRowidOff = fts5LeafFirstRowidOff(pLeaf);
      if( iRowidOff>=iOff ){
        p->rc = FTS5_CORRUPT;
      }else{
        iOff += fts5GetVarint32(&pLeaf->p[iOff], nTerm);
        res = memcmp(&pLeaf->p[iOff], zIdxTerm, MIN(nTerm, nIdxTerm));
        if( res==0 ) res = nTerm - nIdxTerm;
        if( res<0 ) p->rc = FTS5_CORRUPT;
      }

      fts5IntegrityCheckPgidx(p, pLeaf);
    }
    fts5DataRelease(pLeaf);
    if( p->rc ) break;


    /* Now check that the iter.nEmpty leaves following the current leaf
    ** (a) exist and (b) contain no terms. */

      for(pDlidx=fts5DlidxIterInit(p, 0, iSegid, iIdxLeaf);
          fts5DlidxIterEof(p, pDlidx)==0;
          fts5DlidxIterNext(p, pDlidx)
      ){

        /* Check any rowid-less pages that occur before the current leaf. */
        for(iPg=iPrevLeaf+1; iPg<fts5DlidxIterPgno(pDlidx); iPg++){
          iKey = FTS5_SEGMENT_ROWID(iSegid, iPg);
          pLeaf = fts5DataRead(p, iKey);
          if( pLeaf ){
            if( fts5LeafFirstRowidOff(pLeaf)!=0 ) p->rc = FTS5_CORRUPT;
            fts5DataRelease(pLeaf);
          }
        }
        iPrevLeaf = fts5DlidxIterPgno(pDlidx);

        /* Check that the leaf page indicated by the iterator really does
        ** contain the rowid suggested by the same. */
        iKey = FTS5_SEGMENT_ROWID(iSegid, iPrevLeaf);
        pLeaf = fts5DataRead(p, iKey);
        if( pLeaf ){
          i64 iRowid;
          int iRowidOff = fts5LeafFirstRowidOff(pLeaf);
          ASSERT_SZLEAF_OK(pLeaf);
          if( iRowidOff>=pLeaf->szLeaf ){
            p->rc = FTS5_CORRUPT;
          }else{
            fts5GetVarint(&pLeaf->p[iRowidOff], (u64*)&iRowid);
            if( iRowid!=fts5DlidxIterRowid(pDlidx) ) p->rc = FTS5_CORRUPT;
          }
          fts5DataRelease(pLeaf);
        }

static void fts5DebugRowid(int *pRc, Fts5Buffer *pBuf, i64 iKey){
  int iSegid, iHeight, iPgno, bDlidx;       /* Rowid compenents */
  fts5DecodeRowid(iKey, &iSegid, &bDlidx, &iHeight, &iPgno);

  if( iSegid==0 ){
    if( iKey==FTS5_AVERAGES_ROWID ){
      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "{averages} ");
    }else{
      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "{structure}");
    }
  }
  else{
    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "{%ssegid=%d h=%d pgno=%d}",
        bDlidx ? "dlidx " : "", iSegid, iHeight, iPgno
    );
  }
}

static void fts5DebugStructure(
  int *pRc,                       /* IN/OUT: error code */
  Fts5Buffer *pBuf,
  Fts5Structure *p
){
  int iLvl, iSeg;                 /* Iterate through levels, segments */

  for(iLvl=0; iLvl<p->nLevel; iLvl++){
    Fts5StructureLevel *pLvl = &p->aLevel[iLvl];
    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, 
        " {lvl=%d nMerge=%d nSeg=%d", iLvl, pLvl->nMerge, pLvl->nSeg
    );
    for(iSeg=0; iSeg<pLvl->nSeg; iSeg++){
      Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " {id=%d leaves=%d..%d}", 

          pSeg->iSegid, pSeg->pgnoFirst, pSeg->pgnoLast
      );
    }
    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "}");
  }
}

/*

** may or may not finish within the buffer. This function appends a text
** representation of the part of the doclist that is present to buffer
** pBuf. 
**
** The return value is the number of bytes read from the input buffer.
*/
static int fts5DecodeDoclist(int *pRc, Fts5Buffer *pBuf, const u8 *a, int n){
  i64 iDocid = 0;
  int iOff = 0;

  if( n>0 ){
    iOff = sqlite3Fts5GetVarint(a, (u64*)&iDocid);
    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " id=%lld", iDocid);
  }
  while( iOff<n ){
    int nPos;
    int bDummy;
    iOff += fts5GetPoslistSize(&a[iOff], &nPos, &bDummy);
    iOff += fts5DecodePoslist(pRc, pBuf, &a[iOff], MIN(n-iOff, nPos));
    if( iOff<n ){
      i64 iDelta;
      iOff += sqlite3Fts5GetVarint(&a[iOff], (u64*)&iDelta);

      iDocid += iDelta;
      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " id=%lld", iDocid);
    }
  }

  return iOff;
}

/*

  Fts5Buffer s;                   /* Build up text to return here */
  int rc = SQLITE_OK;             /* Return code */
  int nSpace = 0;

  assert( nArg==2 );
  memset(&s, 0, sizeof(Fts5Buffer));
  iRowid = sqlite3_value_int64(apVal[0]);

  /* Make a copy of the second argument (a blob) in aBlob[]. The aBlob[]
  ** copy is followed by FTS5_DATA_ZERO_PADDING 0x00 bytes, which prevents
  ** buffer overreads even if the record is corrupt.  */
  n = sqlite3_value_bytes(apVal[1]);
  aBlob = sqlite3_value_blob(apVal[1]);

  nSpace = n + FTS5_DATA_ZERO_PADDING;
  a = (u8*)sqlite3Fts5MallocZero(&rc, nSpace);
  if( a==0 ) goto decode_out;
  memcpy(a, aBlob, n);


  fts5DecodeRowid(iRowid, &iSegid, &bDlidx, &iHeight, &iPgno);

  fts5DebugRowid(&rc, &s, iRowid);
  if( bDlidx ){
    Fts5Data dlidx;
    Fts5DlidxLvl lvl;

    dlidx.p = a;
    dlidx.nn = n;

    memset(&lvl, 0, sizeof(Fts5DlidxLvl));
    lvl.pData = &dlidx;
    lvl.iLeafPgno = iPgno;

    for(fts5DlidxLvlNext(&lvl); lvl.bEof==0; fts5DlidxLvlNext(&lvl)){
      sqlite3Fts5BufferAppendPrintf(&rc, &s, 
          " %d(%lld)", lvl.iLeafPgno, lvl.iRowid
      );
    }
  }else if( iSegid==0 ){
    if( iRowid==FTS5_AVERAGES_ROWID ){
      /* todo */
    }else{
      fts5DecodeStructure(&rc, &s, a, n);
    }
  }else{
    Fts5Buffer term;              /* Current term read from page */
    int szLeaf;                   /* Offset of pgidx in a[] */
    int iPgidxOff;
    int iPgidxPrev = 0;           /* Previous value read from pgidx */
    int iTermOff = 0;
    int iRowidOff = 0;
    int iOff;
    int nDoclist;


    memset(&term, 0, sizeof(Fts5Buffer));

    if( n<4 ){
      sqlite3Fts5BufferSet(&rc, &s, 8, (const u8*)"corrupt");
      goto decode_out;
    }else{
      iRowidOff = fts5GetU16(&a[0]);
      iPgidxOff = szLeaf = fts5GetU16(&a[2]);
      if( iPgidxOff<n ){
        fts5GetVarint32(&a[iPgidxOff], iTermOff);
      }
    }

    /* Decode the position list tail at the start of the page */
    if( iRowidOff!=0 ){
      iOff = iRowidOff;
    }else if( iTermOff!=0 ){
      iOff = iTermOff;
    }else{
      iOff = szLeaf;
    }
    fts5DecodePoslist(&rc, &s, &a[4], iOff-4);


    /* Decode any more doclist data that appears on the page before the
    ** first term. */
    nDoclist = (iTermOff ? iTermOff : szLeaf) - iOff;
    fts5DecodeDoclist(&rc, &s, &a[iOff], nDoclist);

    while( iPgidxOff<n ){
      int bFirst = (iPgidxOff==szLeaf);     /* True for first term on page */
      int nByte;                            /* Bytes of data */
      int iEnd;
      
      iPgidxOff += fts5GetVarint32(&a[iPgidxOff], nByte);

      iPgidxPrev += nByte;
      iOff = iPgidxPrev;

      if( iPgidxOff<n ){
        fts5GetVarint32(&a[iPgidxOff], nByte);

        iEnd = iPgidxPrev + nByte;

      }else{
        iEnd = szLeaf;
      }

      if( bFirst==0 ){


        iOff += fts5GetVarint32(&a[iOff], nByte);
        term.n = nByte;
      }
      iOff += fts5GetVarint32(&a[iOff], nByte);
      fts5BufferAppendBlob(&rc, &term, nByte, &a[iOff]);
      iOff += nByte;

      sqlite3Fts5BufferAppendPrintf(
          &rc, &s, " term=%.*s", term.n, (const char*)term.p
      );
      iOff += fts5DecodeDoclist(&rc, &s, &a[iOff], iEnd-iOff);


    }

    fts5BufferFree(&term);


















  }
  
 decode_out:
  sqlite3_free(a);
  if( rc==SQLITE_OK ){
    sqlite3_result_text(pCtx, (const char*)s.p, s.n, SQLITE_TRANSIENT);
  }else{

  const char *zArg;
  if( nArg==0 ){
    sqlite3_result_error(pCtx, "should be: fts5_rowid(subject, ....)", -1);
  }else{
    zArg = (const char*)sqlite3_value_text(apVal[0]);
    if( 0==sqlite3_stricmp(zArg, "segment") ){
      i64 iRowid;
      int segid, pgno;
      if( nArg!=3 ){
        sqlite3_result_error(pCtx, 
            "should be: fts5_rowid('segment', segid, pgno))", -1
        );
      }else{
        segid = sqlite3_value_int(apVal[1]);

        pgno = sqlite3_value_int(apVal[2]);
        iRowid = FTS5_SEGMENT_ROWID(segid, pgno);
        sqlite3_result_int64(pCtx, iRowid);
      }
    }else{
      sqlite3_result_error(pCtx, 
        "first arg to fts5_rowid() must be 'segment'" , -1


      );
    }
  }
}

/*
** This is called as part of registering the FTS5 module with database

** structures should not be corrupt. Otherwise, true. If it is false, extra
** assert() conditions in the fts5 code are activated - conditions that are
** only true if it is guaranteed that the fts5 database is not corrupt.
*/
int sqlite3_fts5_may_be_corrupt = 1;


typedef struct Fts5Auxdata Fts5Auxdata;
typedef struct Fts5Auxiliary Fts5Auxiliary;
typedef struct Fts5Cursor Fts5Cursor;
typedef struct Fts5Sorter Fts5Sorter;
typedef struct Fts5Table Fts5Table;

typedef struct Fts5TokenizerModule Fts5TokenizerModule;

/*
** NOTES ON TRANSACTIONS: 
**
** SQLite invokes the following virtual table methods as transactions are 
** opened and closed by the user:

  }else if( 0==sqlite3_stricmp("optimize", z) ){
    rc = sqlite3Fts5StorageOptimize(pTab->pStorage);
  }else if( 0==sqlite3_stricmp("merge", z) ){
    int nMerge = sqlite3_value_int(pVal);
    rc = sqlite3Fts5StorageMerge(pTab->pStorage, nMerge);
  }else if( 0==sqlite3_stricmp("integrity-check", z) ){
    rc = sqlite3Fts5StorageIntegrity(pTab->pStorage);
#ifdef SQLITE_DEBUG
  }else if( 0==sqlite3_stricmp("prefix-index", z) ){
    pConfig->bPrefixIndex = sqlite3_value_int(pVal);
#endif
  }else{
    rc = sqlite3Fts5IndexLoadConfig(pTab->pIndex);
    if( rc==SQLITE_OK ){
      rc = sqlite3Fts5ConfigSetValue(pTab->pConfig, z, pVal, &bError);
    }
    if( rc==SQLITE_OK ){
      if( bError ){

  return sqlite3Fts5StorageRowCount(pTab->pStorage, pnRow);
}

static int fts5ApiTokenize(
  Fts5Context *pCtx, 
  const char *pText, int nText, 
  void *pUserData,
  int (*xToken)(void*, int, const char*, int, int, int)
){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
  return sqlite3Fts5Tokenize(
      pTab->pConfig, FTS5_TOKENIZE_AUX, pText, nText, pUserData, xToken
  );
}

static int fts5ApiPhraseCount(Fts5Context *pCtx){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
  return sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
}

    }
  }
  return rc;
}

static int fts5ColumnSizeCb(
  void *pContext,                 /* Pointer to int */
  int tflags,
  const char *pToken,             /* Buffer containing token */
  int nToken,                     /* Size of token in bytes */
  int iStart,                     /* Start offset of token */
  int iEnd                        /* End offset of token */
){
  int *pCnt = (int*)pContext;
  if( (tflags & FTS5_TOKEN_COLOCATED)==0 ){
    (*pCnt)++;
  }
  return SQLITE_OK;
}

static int fts5ApiColumnSize(Fts5Context *pCtx, int iCol, int *pnToken){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
  Fts5Config *pConfig = pTab->pConfig;

      for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
        if( pConfig->abUnindexed[i]==0 ){
          const char *z; int n;
          void *p = (void*)(&pCsr->aColumnSize[i]);
          pCsr->aColumnSize[i] = 0;
          rc = fts5ApiColumnText(pCtx, i, &z, &n);
          if( rc==SQLITE_OK ){
            rc = sqlite3Fts5Tokenize(
                pConfig, FTS5_TOKENIZE_AUX, z, n, p, fts5ColumnSizeCb
            );
          }
        }
      }
    }
    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_DOCSIZE);
  }
  if( iCol<0 ){

  rc = fts5OpenMethod(pCsr->base.pVtab, (sqlite3_vtab_cursor**)&pNew);
  if( rc==SQLITE_OK ){
    Fts5Config *pConf = pTab->pConfig;
    pNew->ePlan = FTS5_PLAN_MATCH;
    pNew->iFirstRowid = SMALLEST_INT64;
    pNew->iLastRowid = LARGEST_INT64;
    pNew->base.pVtab = (sqlite3_vtab*)pTab;
    rc = sqlite3Fts5ExprClonePhrase(pConf, pCsr->pExpr, iPhrase, &pNew->pExpr);
  }

  if( rc==SQLITE_OK ){
    for(rc = fts5CursorFirst(pTab, pNew, 0);
        rc==SQLITE_OK && CsrFlagTest(pNew, FTS5CSR_EOF)==0;
        rc = fts5NextMethod((sqlite3_vtab_cursor*)pNew)
    ){

  pGlobal = (Fts5Global*)sqlite3_malloc(sizeof(Fts5Global));
  if( pGlobal==0 ){
    rc = SQLITE_NOMEM;
  }else{
    void *p = (void*)pGlobal;
    memset(pGlobal, 0, sizeof(Fts5Global));
    pGlobal->db = db;
    pGlobal->api.iVersion = 2;
    pGlobal->api.xCreateFunction = fts5CreateAux;
    pGlobal->api.xCreateTokenizer = fts5CreateTokenizer;
    pGlobal->api.xFindTokenizer = fts5FindTokenizer;
    rc = sqlite3_create_module_v2(db, "fts5", &fts5Mod, p, fts5ModuleDestroy);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5IndexInit(db);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5ExprInit(pGlobal, db);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5AuxInit(&pGlobal->api);

};

/*
** Tokenization callback used when inserting tokens into the FTS index.
*/
static int fts5StorageInsertCallback(
  void *pContext,                 /* Pointer to Fts5InsertCtx object */
  int tflags,
  const char *pToken,             /* Buffer containing token */
  int nToken,                     /* Size of token in bytes */
  int iStart,                     /* Start offset of token */
  int iEnd                        /* End offset of token */
){
  Fts5InsertCtx *pCtx = (Fts5InsertCtx*)pContext;
  Fts5Index *pIdx = pCtx->pStorage->pIndex;
  if( (tflags & FTS5_TOKEN_COLOCATED)==0 || pCtx->szCol==0 ){
    pCtx->szCol++;
  }
  return sqlite3Fts5IndexWrite(pIdx, pCtx->iCol, pCtx->szCol-1, pToken, nToken);
}

/*
** If a row with rowid iDel is present in the %_content table, add the
** delete-markers to the FTS index necessary to delete it. Do not actually
** remove the %_content row at this time though.
*/

      ctx.pStorage = p;
      ctx.iCol = -1;
      rc = sqlite3Fts5IndexBeginWrite(p->pIndex, iDel);
      for(iCol=1; rc==SQLITE_OK && iCol<=pConfig->nCol; iCol++){
        if( pConfig->abUnindexed[iCol-1] ) continue;
        ctx.szCol = 0;
        rc = sqlite3Fts5Tokenize(pConfig, 
            FTS5_TOKENIZE_DOCUMENT,
            (const char*)sqlite3_column_text(pSeek, iCol),
            sqlite3_column_bytes(pSeek, iCol),
            (void*)&ctx,
            fts5StorageInsertCallback
        );
        p->aTotalSize[iCol-1] -= (i64)ctx.szCol;
      }

**
** Return SQLITE_OK if successful, or an SQLite error code if an error
** occurs.
*/
static int fts5StorageLoadTotals(Fts5Storage *p, int bCache){
  int rc = SQLITE_OK;
  if( p->bTotalsValid==0 ){






    rc = sqlite3Fts5IndexGetAverages(p->pIndex, &p->nTotalRow, p->aTotalSize);









    p->bTotalsValid = bCache;
  }
  return rc;
}

/*
** Store the current contents of the p->nTotalRow and p->aTotalSize[] 

    ctx.iCol = -1;

    rc = sqlite3Fts5IndexBeginWrite(p->pIndex, iDel);
    for(iCol=0; rc==SQLITE_OK && iCol<pConfig->nCol; iCol++){
      if( pConfig->abUnindexed[iCol] ) continue;
      ctx.szCol = 0;
      rc = sqlite3Fts5Tokenize(pConfig, 
        FTS5_TOKENIZE_DOCUMENT,
        (const char*)sqlite3_value_text(apVal[iCol]),
        sqlite3_value_bytes(apVal[iCol]),
        (void*)&ctx,
        fts5StorageInsertCallback
      );
      p->aTotalSize[iCol] -= (i64)ctx.szCol;
    }

    sqlite3Fts5BufferZero(&buf);
    rc = sqlite3Fts5IndexBeginWrite(p->pIndex, iRowid);
    for(ctx.iCol=0; rc==SQLITE_OK && ctx.iCol<pConfig->nCol; ctx.iCol++){
      ctx.szCol = 0;
      if( pConfig->abUnindexed[ctx.iCol]==0 ){
        rc = sqlite3Fts5Tokenize(pConfig, 
            FTS5_TOKENIZE_DOCUMENT,
            (const char*)sqlite3_column_text(pScan, ctx.iCol+1),
            sqlite3_column_bytes(pScan, ctx.iCol+1),
            (void*)&ctx,
            fts5StorageInsertCallback
        );
      }
      sqlite3Fts5BufferAppendVarint(&rc, &buf, ctx.szCol);

    rc = sqlite3Fts5IndexBeginWrite(p->pIndex, *piRowid);
    ctx.pStorage = p;
  }
  for(ctx.iCol=0; rc==SQLITE_OK && ctx.iCol<pConfig->nCol; ctx.iCol++){
    ctx.szCol = 0;
    if( pConfig->abUnindexed[ctx.iCol]==0 ){
      rc = sqlite3Fts5Tokenize(pConfig, 
          FTS5_TOKENIZE_DOCUMENT,
          (const char*)sqlite3_value_text(apVal[ctx.iCol+2]),
          sqlite3_value_bytes(apVal[ctx.iCol+2]),
          (void*)&ctx,
          fts5StorageInsertCallback
      );
    }
    sqlite3Fts5BufferAppendVarint(&rc, &buf, ctx.szCol);

};

/*
** Tokenization callback used by integrity check.
*/
static int fts5StorageIntegrityCallback(
  void *pContext,                 /* Pointer to Fts5InsertCtx object */
  int tflags,
  const char *pToken,             /* Buffer containing token */
  int nToken,                     /* Size of token in bytes */
  int iStart,                     /* Start offset of token */
  int iEnd                        /* End offset of token */
){
  Fts5IntegrityCtx *pCtx = (Fts5IntegrityCtx*)pContext;
  if( (tflags & FTS5_TOKEN_COLOCATED)==0 || pCtx->szCol==0 ){
    pCtx->szCol++;
  }
  pCtx->cksum ^= sqlite3Fts5IndexCksum(
      pCtx->pConfig, pCtx->iRowid, pCtx->iCol, pCtx->szCol-1, pToken, nToken
  );
  return SQLITE_OK;
}

/*
** Check that the contents of the FTS index match that of the %_content
** table. Return SQLITE_OK if they do, or SQLITE_CORRUPT if not. Return

  rc = fts5StorageGetStmt(p, FTS5_STMT_SCAN, &pScan, 0);
  if( rc==SQLITE_OK ){
    int rc2;
    while( SQLITE_ROW==sqlite3_step(pScan) ){
      int i;
      ctx.iRowid = sqlite3_column_int64(pScan, 0);
      ctx.szCol = 0;
      if( pConfig->bColumnsize ){
        rc = sqlite3Fts5StorageDocsize(p, ctx.iRowid, aColSize);
      }
      for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
        if( pConfig->abUnindexed[i] ) continue;
        ctx.iCol = i;
        ctx.szCol = 0;
        rc = sqlite3Fts5Tokenize(pConfig, 
            FTS5_TOKENIZE_DOCUMENT,
            (const char*)sqlite3_column_text(pScan, i+1),
            sqlite3_column_bytes(pScan, i+1),
            (void*)&ctx,
            fts5StorageIntegrityCallback
        );
        if( pConfig->bColumnsize && ctx.szCol!=aColSize[i] ){
          rc = FTS5_CORRUPT;
        }
        aTotalSize[i] += ctx.szCol;
      }
      if( rc!=SQLITE_OK ) break;
    }
    rc2 = sqlite3_reset(pScan);
    if( rc==SQLITE_OK ) rc = rc2;
  }

  /* Check that the %_docsize and %_content tables contain the expected
  ** number of rows.  */
  if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_NORMAL ){
    i64 nRow;
    rc = fts5StorageCount(p, "content", &nRow);
    if( rc==SQLITE_OK && nRow!=p->nTotalRow ) rc = FTS5_CORRUPT;
  }
  if( rc==SQLITE_OK && pConfig->bColumnsize ){
    i64 nRow;
    rc = fts5StorageCount(p, "docsize", &nRow);
    if( rc==SQLITE_OK && nRow!=p->nTotalRow ) rc = FTS5_CORRUPT;
  }

  /* Pass the expected checksum down to the FTS index module. It will
  ** verify, amongst other things, that it matches the checksum generated by

** each table column. This function reads the %_docsize record for the
** specified rowid and populates aCol[] with the results.
**
** An SQLite error code is returned if an error occurs, or SQLITE_OK
** otherwise.
*/
int sqlite3Fts5StorageDocsize(Fts5Storage *p, i64 iRowid, int *aCol){
  int nCol = p->pConfig->nCol;    /* Number of user columns in table */
  sqlite3_stmt *pLookup = 0;      /* Statement to query %_docsize */
  int rc;                         /* Return Code */

  assert( p->pConfig->bColumnsize );
  rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP_DOCSIZE, &pLookup, 0);
  if( rc==SQLITE_OK ){
    int bCorrupt = 1;
    sqlite3_bind_int64(pLookup, 1, iRowid);
    if( SQLITE_ROW==sqlite3_step(pLookup) ){
      const u8 *aBlob = sqlite3_column_blob(pLookup, 0);
      int nBlob = sqlite3_column_bytes(pLookup, 0);
      if( 0==fts5StorageDecodeSizeArray(aCol, nCol, aBlob, nBlob) ){

typedef struct F5tAuxData F5tAuxData;
struct F5tAuxData {
  Tcl_Obj *pObj;
};

static int xTokenizeCb(
  void *pCtx, 
  int tflags,
  const char *zToken, int nToken, 
  int iStart, int iEnd
){
  F5tFunction *p = (F5tFunction*)pCtx;
  Tcl_Obj *pEval = Tcl_DuplicateObj(p->pScript);
  int rc;

  Tcl_Obj *pRet;
  int bSubst;
  const char *zInput;
};

static int xTokenizeCb2(
  void *pCtx, 
  int tflags,
  const char *zToken, int nToken, 
  int iStart, int iEnd
){
  F5tTokenizeCtx *p = (F5tTokenizeCtx*)pCtx;
  if( p->bSubst ){
    Tcl_ListObjAppendElement(0, p->pRet, Tcl_NewStringObj(zToken, nToken));
    Tcl_ListObjAppendElement(

  }

  pRet = Tcl_NewObj();
  Tcl_IncrRefCount(pRet);
  ctx.bSubst = (objc==5);
  ctx.pRet = pRet;
  ctx.zInput = zText;
  rc = tokenizer.xTokenize(
      pTok, (void*)&ctx, FTS5_TOKENIZE_DOCUMENT, zText, nText, xTokenizeCb2
  );
  tokenizer.xDelete(pTok);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, "error in tokenizer.xTokenize()", 0);
    Tcl_DecrRefCount(pRet);
    return TCL_ERROR;
  }

/*************************************************************************
** Start of tokenizer wrapper.
*/

typedef struct F5tTokenizerContext F5tTokenizerContext;
typedef struct F5tTokenizerCb F5tTokenizerCb;
typedef struct F5tTokenizerModule F5tTokenizerModule;
typedef struct F5tTokenizerInstance F5tTokenizerInstance;

struct F5tTokenizerContext {
  void *pCtx;
  int (*xToken)(void*, int, const char*, int, int, int);
};

struct F5tTokenizerModule {
  Tcl_Interp *interp;
  Tcl_Obj *pScript;
  F5tTokenizerContext *pContext;
};

struct F5tTokenizerInstance {
  Tcl_Interp *interp;
  Tcl_Obj *pScript;
  F5tTokenizerContext *pContext;
};

static int f5tTokenizerCreate(
  void *pCtx, 
  const char **azArg, 

  Tcl_DecrRefCount(pInst->pScript);
  ckfree((char *)pInst);
}

static int f5tTokenizerTokenize(
  Fts5Tokenizer *p, 
  void *pCtx,
  int flags,
  const char *pText, int nText, 
  int (*xToken)(void*, int, const char*, int, int, int)
){
  F5tTokenizerInstance *pInst = (F5tTokenizerInstance*)p;
  void *pOldCtx;
  int (*xOldToken)(void*, int, const char*, int, int, int);
  Tcl_Obj *pEval;
  int rc;
  const char *zFlags;

  pOldCtx = pInst->pContext->pCtx;
  xOldToken = pInst->pContext->xToken;

  pInst->pContext->pCtx = pCtx;
  pInst->pContext->xToken = xToken;

  assert( 
      flags==FTS5_TOKENIZE_DOCUMENT
   || flags==FTS5_TOKENIZE_AUX
   || flags==FTS5_TOKENIZE_QUERY
   || flags==(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)
  );
  pEval = Tcl_DuplicateObj(pInst->pScript);
  Tcl_IncrRefCount(pEval);
  switch( flags ){
    case FTS5_TOKENIZE_DOCUMENT:
      zFlags = "document";
      break;
    case FTS5_TOKENIZE_AUX:
      zFlags = "aux";
      break;
    case FTS5_TOKENIZE_QUERY:
      zFlags = "query";
      break;
    case (FTS5_TOKENIZE_PREFIX | FTS5_TOKENIZE_QUERY):
      zFlags = "prefixquery";
      break;
    default:
      assert( 0 );
      zFlags = "invalid";
      break;
  }

  Tcl_ListObjAppendElement(pInst->interp, pEval, Tcl_NewStringObj(zFlags, -1));
  Tcl_ListObjAppendElement(pInst->interp, pEval, Tcl_NewStringObj(pText,nText));


  rc = Tcl_EvalObjEx(pInst->interp, pEval, TCL_GLOBAL_ONLY);

  Tcl_DecrRefCount(pEval);

  pInst->pContext->pCtx = pOldCtx;
  pInst->pContext->xToken = xOldToken;
  return rc;
}

/*
** sqlite3_fts5_token ?-colocated? TEXT START END
*/
static int f5tTokenizerReturn(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  F5tTokenizerContext *p = (F5tTokenizerContext*)clientData;
  int iStart;
  int iEnd;
  int nToken;
  int tflags = 0;
  char *zToken;
  int rc;

  if( objc==5 ){
    int nArg;
    char *zArg = Tcl_GetStringFromObj(objv[1], &nArg);
    if( nArg<=10 && nArg>=2 && memcmp("-colocated", zArg, nArg)==0 ){
      tflags |= FTS5_TOKEN_COLOCATED;
    }else{
      goto usage;
    }
  }else if( objc!=4 ){
    goto usage;
  }

  zToken = Tcl_GetStringFromObj(objv[objc-3], &nToken);
  if( Tcl_GetIntFromObj(interp, objv[objc-2], &iStart) 
   || Tcl_GetIntFromObj(interp, objv[objc-1], &iEnd) 
  ){
    return TCL_ERROR;
  }

  if( p->xToken==0 ){
    Tcl_AppendResult(interp, 
        "sqlite3_fts5_token may only be used by tokenizer callback", 0
    );
    return TCL_ERROR;
  }

  rc = p->xToken(p->pCtx, tflags, zToken, nToken, iStart, iEnd);

  Tcl_SetResult(interp, (char*)sqlite3ErrName(rc), TCL_VOLATILE);

  return TCL_OK;

 usage:

  Tcl_WrongNumArgs(interp, 1, objv, "?-colocated? TEXT START END");
  return TCL_ERROR;
}

static void f5tDelTokenizer(void *pCtx){
  F5tTokenizerModule *pMod = (F5tTokenizerModule*)pCtx;
  Tcl_DecrRefCount(pMod->pScript);
  ckfree((char *)pMod);
}

  Fts5Context *pFts,              /* First arg to pass to pApi functions */
  sqlite3_context *pCtx,          /* Context for returning result/error */
  int nVal,                       /* Number of values in apVal[] array */
  sqlite3_value **apVal           /* Array of trailing arguments */
){
  const char *zArg;
  Fts5MatchinfoCtx *p;
  int rc = SQLITE_OK;

  if( nVal>0 ){
    zArg = (const char*)sqlite3_value_text(apVal[0]);
  }else{
    zArg = "pcx";
  }

  p = (Fts5MatchinfoCtx*)pApi->xGetAuxdata(pFts, 0);
  if( p==0 || sqlite3_stricmp(zArg, p->zArg) ){
    p = fts5MatchinfoNew(pApi, pFts, pCtx, zArg);
    if( p==0 ){
      rc = SQLITE_NOMEM;
    }else{
      rc = pApi->xSetAuxdata(pFts, p, sqlite3_free);

    }
  }

  if( rc==SQLITE_OK ){
    rc = fts5MatchinfoIter(pApi, pFts, p, fts5MatchinfoLocalCb);
  }
  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pCtx, rc);
  }else{
    /* No errors has occured, so return a copy of the array of integers. */
    int nByte = p->nRet * sizeof(u32);
    sqlite3_result_blob(pCtx, (void*)p->aRet, nByte, SQLITE_TRANSIENT);
  }

/*
** Tokenize some text using the ascii tokenizer.
*/
static int fts5AsciiTokenize(
  Fts5Tokenizer *pTokenizer,
  void *pCtx,
  int flags,
  const char *pText, int nText,
  int (*xToken)(void*, int, const char*, int nToken, int iStart, int iEnd)
){
  AsciiTokenizer *p = (AsciiTokenizer*)pTokenizer;
  int rc = SQLITE_OK;
  int ie;
  int is = 0;

  char aFold[64];

        break;
      }
      nFold = nByte*2;
    }
    asciiFold(pFold, &pText[is], nByte);

    /* Invoke the token callback */
    rc = xToken(pCtx, 0, pFold, nByte, is, ie);
    is = ie+1;
  }
  
  if( pFold!=aFold ) sqlite3_free(pFold);
  if( rc==SQLITE_DONE ) rc = SQLITE_OK;
  return rc;
}

  assert( (sqlite3Fts5UnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 );
  return sqlite3Fts5UnicodeIsalnum(iCode) ^ fts5UnicodeIsException(p, iCode);
}

static int fts5UnicodeTokenize(
  Fts5Tokenizer *pTokenizer,
  void *pCtx,
  int flags,
  const char *pText, int nText,
  int (*xToken)(void*, int, const char*, int nToken, int iStart, int iEnd)
){
  Unicode61Tokenizer *p = (Unicode61Tokenizer*)pTokenizer;
  int rc = SQLITE_OK;
  unsigned char *a = p->aTokenChar;

  unsigned char *zTerm = (unsigned char*)&pText[nText];
  unsigned char *zCsr = (unsigned char *)pText;

        }
        zCsr++;
      }
      ie = zCsr - (unsigned char*)pText;
    }

    /* Invoke the token callback */
    rc = xToken(pCtx, 0, aFold, zOut-aFold, is, ie); 
  }
  
 tokenize_done:
  if( rc==SQLITE_DONE ) rc = SQLITE_OK;
  return rc;
}

  *ppOut = (Fts5Tokenizer*)pRet;
  return rc;
}

typedef struct PorterContext PorterContext;
struct PorterContext {
  void *pCtx;
  int (*xToken)(void*, int, const char*, int, int, int);
  char *aBuf;
};

typedef struct PorterRule PorterRule;
struct PorterRule {
  const char *zSuffix;
  int nSuffix;

      *pnBuf = nBuf-1;
    }
  }
}

static int fts5PorterCb(
  void *pCtx, 
  int tflags,
  const char *pToken, 
  int nToken, 
  int iStart, 
  int iEnd
){
  PorterContext *p = (PorterContext*)pCtx;

  /* Step 5b. */
  if( nBuf>1 && aBuf[nBuf-1]=='l' 
   && aBuf[nBuf-2]=='l' && fts5Porter_MGt1(aBuf, nBuf-1) 
  ){
    nBuf--;
  }

  return p->xToken(p->pCtx, tflags, aBuf, nBuf, iStart, iEnd);

 pass_through:
  return p->xToken(p->pCtx, tflags, pToken, nToken, iStart, iEnd);
}

/*
** Tokenize using the porter tokenizer.
*/
static int fts5PorterTokenize(
  Fts5Tokenizer *pTokenizer,
  void *pCtx,
  int flags,
  const char *pText, int nText,
  int (*xToken)(void*, int, const char*, int nToken, int iStart, int iEnd)
){
  PorterTokenizer *p = (PorterTokenizer*)pTokenizer;
  PorterContext sCtx;
  sCtx.xToken = xToken;
  sCtx.pCtx = pCtx;
  sCtx.aBuf = p->aBuf;
  return p->tokenizer.xTokenize(
      p->pTokenizer, (void*)&sCtx, flags, pText, nText, fts5PorterCb
  );
}

/*
** Register all built-in tokenizers with FTS5.
*/
int sqlite3Fts5TokenizerInit(fts5_api *pApi){

        aBuiltin[i].zName,
        (void*)pApi,
        &aBuiltin[i].x,
        0
    );
  }

  return rc;
}

proc OR {args} {
  sort_poslist [concat {*}$args]
}
proc NOT {a b} {
  if {[llength $b]>0} { return [list] }
  return $a
}

#-------------------------------------------------------------------------
# This command is similar to [split], except that it also provides the
# start and end offsets of each token. For example:
#
#   [fts5_tokenize_split "abc d ef"] -> {abc 0 3 d 4 5 ef 6 8}
#

proc gobble_whitespace {textvar} {
  upvar $textvar t
  regexp {([ ]*)(.*)} $t -> space t
  return [string length $space]
}

proc gobble_text {textvar wordvar} {
  upvar $textvar t
  upvar $wordvar w
  regexp {([^ ]*)(.*)} $t -> w t
  return [string length $w]
}

proc fts5_tokenize_split {text} {
  set token ""
  set ret [list]
  set iOff [gobble_whitespace text]
  while {[set nToken [gobble_text text word]]} {
    lappend ret $word $iOff [expr $iOff+$nToken]
    incr iOff $nToken
    incr iOff [gobble_whitespace text]
  }

  set ret
}

}
do_execsql_test 2.1 {
  INSERT INTO t1 VALUES('a b c', 'd e f');
}

do_test 2.2 {
  execsql { SELECT fts5_decode(id, block) FROM t1_data WHERE id==10 }
} {/{{structure} {lvl=0 nMerge=0 nSeg=1 {id=[0123456789]* leaves=1..1}}}/}

foreach w {a b c d e f} {
  do_execsql_test 2.3.$w.asc {
    SELECT rowid FROM t1 WHERE t1 MATCH $w;
  } {1}
  do_execsql_test 2.3.$w.desc {
    SELECT rowid FROM t1 WHERE t1 MATCH $w ORDER BY rowid DESC;

  do_execsql_test 5.$i.1 { INSERT INTO t1 VALUES($x, $y) }
  do_execsql_test 5.$i.2 { INSERT INTO t1(t1) VALUES('integrity-check') }
  if {[set_test_counter errors]} break
}

#-------------------------------------------------------------------------
#

reset_db
do_execsql_test 6.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(x,y);
  INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
}

do_execsql_test 6.1 {

      set y [doc]
      set z [doc]
      set rowid [expr int(rand() * 100)]
      execsql { REPLACE INTO t1(rowid,x,y,z) VALUES($rowid, $x, $y, $z) }
    }
    execsql { INSERT INTO t1(t1) VALUES('integrity-check'); }
  } {}
  if {[set_test_counter errors]} break
}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 8.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(x, prefix="1,2,3");

} {}

do_execsql_test 13.5 {
  SELECT rowid FROM t1 WHERE t1 MATCH 'o';
} {1}

do_execsql_test 13.6 {
  SELECT rowid FROM t1 WHERE t1 MATCH '""';
} {}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 14.1 {
  CREATE VIRTUAL TABLE t1 USING fts5(x, y);

}
do_execsql_test 18.2 {
  SELECT t1.rowid, t2.rowid FROM t1, t2 WHERE t2 MATCH t1.a AND t1.rowid = t2.c
} {1 1}
do_execsql_test 18.3 {
  SELECT t1.rowid, t2.rowid FROM t2, t1 WHERE t2 MATCH t1.a AND t1.rowid = t2.c
} {1 1}

#--------------------------------------------------------------------
# fts5 table in the temp schema.
#
reset_db
do_execsql_test 19.0 {
  CREATE VIRTUAL TABLE temp.t1 USING fts5(x);
  INSERT INTO t1 VALUES('x y z');
  INSERT INTO t1 VALUES('w x 1');
  SELECT rowid FROM t1 WHERE t1 MATCH 'x';
} {1 2}

#--------------------------------------------------------------------
# Test that 6 and 7 byte varints can be read.
#
reset_db
do_execsql_test 20.0 {
  CREATE VIRTUAL TABLE temp.tmp USING fts5(x);
}
set ::ids [list \
  0 [expr 1<<36] [expr 2<<36] [expr 1<<43] [expr 2<<43]
]
do_test 20.1 {
  foreach id $::ids {
    execsql { INSERT INTO tmp(rowid, x) VALUES($id, 'x y z') }
  }
  execsql { SELECT rowid FROM tmp WHERE tmp MATCH 'y' }
} $::ids



finish_test

        }
      }
      if {$bMatch} { lappend ret $rowid }
    }
    return $ret
  }

  do_execsql_test $T.integrity {
    INSERT INTO t1(t1) VALUES('integrity-check');
  }
  
  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*} 

  2 { SELECT rowid FROM t1 WHERE t1 MATCH 'x + w'   }  [list $W]
  3 { SELECT rowid FROM t1 WHERE t1 MATCH 'x AND w' }  [list $W]
  4 { SELECT rowid FROM t1 WHERE t1 MATCH 'y AND x' }  [list $Y]
" {

  do_test 1.6.$tn.1 {
    set n [execsql_reads $q]
    #puts -nonewline "(n=$n nReadX=$nReadX)"
    expr {$n < ($nReadX / 8)}
  } {1}

  do_test 1.6.$tn.2 {
    set n [execsql_reads "$q ORDER BY rowid DESC"]
    #puts -nonewline "(n=$n nReadX=$nReadX)"
    expr {$n < ($nReadX / 8)}
  } {1}

  do_execsql_test 1.6.$tn.3 $q [lsort -int -incr $res]
  do_execsql_test 1.6.$tn.4 "$q ORDER BY rowid DESC" [lsort -int -decr $res]
}

  finish_test
  return
}

do_execsql_test 1.1 {
  CREATE VIRTUAL TABLE ft1 USING fts5(x);
  SELECT * FROM ft1_config;
} {version 4}

do_execsql_test 1.2 {
  INSERT INTO ft1(ft1, rank) VALUES('pgsz', 32);
  SELECT * FROM ft1_config;
} {pgsz 32 version 4}

do_execsql_test 1.3 {
  INSERT INTO ft1(ft1, rank) VALUES('pgsz', 64);
  SELECT * FROM ft1_config;
} {pgsz 64 version 4}

#--------------------------------------------------------------------------
# Test the logic for parsing the rank() function definition.
#
foreach {tn defn} {
  1 "fname()"
  2 "fname(1)"

}
do_execsql_test 3.2.1 {
  SELECT rowid, fts5_test_columnsize(t4) FROM t4 WHERE t4 MATCH 'a'
} {
  1 {-1 0 -1} 2 {-1 0 -1}
}

#-------------------------------------------------------------------------
# Test the integrity-check
#
do_execsql_test 4.1.1 {
  CREATE VIRTUAL TABLE t5 USING fts5(x, columnsize=0);
  INSERT INTO t5 VALUES('1 2 3 4');
  INSERT INTO t5 VALUES('2 4 6 8');
}

breakpoint
do_execsql_test 4.1.2 {
  INSERT INTO t5(t5) VALUES('integrity-check');
}

finish_test

db_save

do_execsql_test 1.2 { INSERT INTO t1(t1) VALUES('integrity-check') }
set segid [lindex [fts5_level_segids t1] 0]

do_test 1.3 {
  execsql {
    DELETE FROM t1_data WHERE rowid = fts5_rowid('segment', $segid, 4);
  }
  catchsql { INSERT INTO t1(t1) VALUES('integrity-check') }
} {1 {database disk image is malformed}}

do_test 1.4 {
  db_restore_and_reopen
  execsql {
    UPDATE t1_data set block = X'00000000' || substr(block, 5) WHERE
    rowid = fts5_rowid('segment', $segid, 4);
  }
  catchsql { INSERT INTO t1(t1) VALUES('integrity-check') }
} {1 {database disk image is malformed}}

db_restore_and_reopen
#db eval {SELECT rowid, fts5_decode(rowid, block) aS r FROM t1_data} {puts $r}

      if {$res == "1 {database disk image is malformed}"} {incr nCorrupt}
      set {} 1
    } {1}

    execsql ROLLBACK
  }

  # do_test 4.$tn.x { expr $nCorrupt>0 } 1
}

}

set doc [string repeat "A B C " 1000]
do_execsql_test 5.0 {
  CREATE VIRTUAL TABLE x5 USING fts5(tt);
  INSERT INTO x5(x5, rank) VALUES('pgsz', 32);
  WITH ii(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM ii WHERE i<10) 
  INSERT INTO x5 SELECT $doc FROM ii;
}

foreach {tn hdr} {
  1 "\x00\x01"
} {
  set tn2 0
  set nCorrupt 0
  foreach rowid [db eval {SELECT rowid FROM x5_data WHERE rowid>10}] {
    if {$rowid & $mask} continue
    incr tn2
    do_test 5.$tn.$tn2 {
      execsql BEGIN

      set fd [db incrblob main x5_data block $rowid]
      fconfigure $fd -encoding binary -translation binary
      puts -nonewline $fd $hdr
      close $fd

      catchsql { INSERT INTO x5(x5) VALUES('integrity-check') }
      set {} {}
    } {}

    execsql ROLLBACK
  }
}

#--------------------------------------------------------------------
reset_db
do_execsql_test 6.1 {
  CREATE VIRTUAL TABLE x5 USING fts5(tt);
  INSERT INTO x5 VALUES('a');
  INSERT INTO x5 VALUES('a a');
  INSERT INTO x5 VALUES('a a a');
  INSERT INTO x5 VALUES('a a a a');

  UPDATE x5_docsize SET sz = X'' WHERE id=3;
}
proc colsize {cmd i} { 
  $cmd xColumnSize $i
}
sqlite3_fts5_create_function db colsize colsize

do_catchsql_test 6.2 {
  SELECT colsize(x5, 0) FROM x5 WHERE x5 MATCH 'a'
} {1 SQLITE_CORRUPT_VTAB}


sqlite3_fts5_may_be_corrupt 0
finish_test

# If SQLITE_ENABLE_FTS5 is defined, omit this file.
ifcapable !fts5 {
  finish_test
  return
}
sqlite3_fts5_may_be_corrupt 1

proc create_t1 {} {
  expr srand(0)
  db func rnddoc fts5_rnddoc
  db eval {
    CREATE VIRTUAL TABLE t1 USING fts5(x);
    INSERT INTO t1(t1, rank) VALUES('pgsz', 64);
    WITH ii(i) AS (SELECT 1 UNION SELECT i+1 FROM ii WHERE i<100)
      INSERT INTO t1 SELECT rnddoc(10) FROM ii;
  }
}

if 1 {

# Create a simple FTS5 table containing 100 documents. Each document 
# contains 10 terms, each of which start with the character "x".
#


do_test 1.0 { create_t1 } {}







do_test 1.1 {
  # Pick out the rowid of the right-most b-tree leaf in the new segment.
  set rowid [db one {
    SELECT max(rowid) FROM t1_data WHERE ((rowid>>31) & 0x0F)==1
  }]
  set L [db one {SELECT length(block) FROM t1_data WHERE rowid = $rowid}]

  SELECT length(block) FROM t2_data WHERE id=1;
} {6}
do_execsql_test 2.2 {
  INSERT INTO t2 VALUES(rnddoc(10));
  SELECT length(block) FROM t2_data WHERE id=1;
} {2}


#-------------------------------------------------------------------------
# Test that missing leaf pages are recognized as corruption.
#
reset_db
do_test 3.0 { create_t1 } {}

do_execsql_test 3.1 {
  SELECT count(*) FROM t1_data;
} {105}

proc do_3_test {tn} {
  set i 0
  foreach ::rowid [db eval "SELECT rowid FROM t1_data WHERE rowid>100"] {
    incr i
    do_test $tn.$i {
      db eval BEGIN
      db eval {DELETE FROM t1_data WHERE rowid = $::rowid}
      list [
        catch { db eval {SELECT rowid FROM t1 WHERE t1 MATCH 'x*'} } msg
      ] $msg
    } {1 {database disk image is malformed}}
    catch { db eval ROLLBACK }
  }
}

do_3_test 3.2

do_execsql_test 3.3 {
  INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
  INSERT INTO t1 SELECT x FROM t1;
  INSERT INTO t1(t1) VALUES('optimize');
} {}

do_3_test 3.4

do_test 3.5 {
  execsql { 
    DELETE FROM t1;
    INSERT INTO t1(t1, rank) VALUES('pgsz', 40);
  }
  for {set i 0} {$i < 1000} {incr i} {
    set rnd [expr int(rand() * 1000)]
    set doc [string repeat "x$rnd " [expr int(rand() * 3) + 1]]
    execsql { INSERT INTO t1(rowid, x) VALUES($i, $doc) }
  }
} {}

do_3_test 3.6

do_test 3.7 {
  execsql {
    INSERT INTO t1(t1, rank) VALUES('pgsz', 40);
    INSERT INTO t1 SELECT x FROM t1;
    INSERT INTO t1(t1) VALUES('optimize');
  }
} {}

do_3_test 3.8

do_test 3.9 {
  execsql { 
    DELETE FROM t1;
    INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
  }
  for {set i 0} {$i < 100} {incr i} {
    set rnd [expr int(rand() * 100)]
    set doc "x[string repeat $rnd 20]"
    execsql { INSERT INTO t1(rowid, x) VALUES($i, $doc) }
  }
} {}

do_3_test 3.10

#-------------------------------------------------------------------------
# Test that segments that end unexpectedly are identified as corruption.
#
reset_db
do_test 4.0 {
  execsql { 
    CREATE VIRTUAL TABLE t1 USING fts5(x);
    INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
  }
  for {set i 0} {$i < 100} {incr i} {
    set rnd [expr int(rand() * 100)]
    set doc "x[string repeat $rnd 20]"
    execsql { INSERT INTO t1(rowid, x) VALUES($i, $doc) }
  }
  execsql { INSERT INTO t1(t1) VALUES('optimize') }
} {}

set nErr 0
for {set i 1} {1} {incr i} {
  set struct [db one {SELECT block FROM t1_data WHERE id=10}]
  binary scan $struct c* var
  set end [lindex $var end]
  if {$end<=$i} break
  lset var end [expr $end - $i]
  set struct [binary format c* $var]
  db eval {
    BEGIN;
    UPDATE t1_data SET block = $struct WHERE id=10;
  }
  do_test 4.1.$i {
    incr nErr [catch { db eval { SELECT rowid FROM t1 WHERE t1 MATCH 'x*' } }]
    set {} {}
  } {}
  catch { db eval ROLLBACK }
}
do_test 4.1.x { expr $nErr>45 } 1

#-------------------------------------------------------------------------
#

# The first argument passed to this command must be a binary blob 
# containing an FTS5 leaf page. This command returns a copy of this
# blob, with the pgidx of the leaf page replaced by a single varint
# containing value $iVal.
#
proc rewrite_pgidx {blob iVal} {
  binary scan $blob SS off1 szLeaf
  if {$iVal<0 || $iVal>=128} {
    error "$iVal out of range!"
  } else {
    set pgidx [binary format c $iVal]
  }

  binary format a${szLeaf}a* $blob $pgidx
}

reset_db
do_execsql_test 5.1 {
  CREATE VIRTUAL TABLE x1 USING fts5(x);
  INSERT INTO x1(x1, rank) VALUES('pgsz', 40);
  BEGIN;
  INSERT INTO x1 VALUES('xaaa xabb xccc xcdd xeee xeff xggg xghh xiii xijj');
  INSERT INTO x1 SELECT x FROM x1;
  INSERT INTO x1 SELECT x FROM x1;
  INSERT INTO x1 SELECT x FROM x1;
  INSERT INTO x1 SELECT x FROM x1;
  INSERT INTO x1(x1) VALUES('optimize');
  COMMIT;
}

#db eval { SELECT fts5_decode(id, block) b from x1_data } { puts $b }
#
db func rewrite_pgidx rewrite_pgidx  
set i 0
foreach rowid [db eval {SELECT rowid FROM x1_data WHERE rowid>100}] {
  foreach val {2 100} {
    do_test 5.2.$val.[incr i] {
      catchsql {
        BEGIN;
        UPDATE x1_data SET block=rewrite_pgidx(block, $val) WHERE id=$rowid;
        SELECT rowid FROM x1 WHERE x1 MATCH 'xa*';
        SELECT rowid FROM x1 WHERE x1 MATCH 'xb*';
        SELECT rowid FROM x1 WHERE x1 MATCH 'xc*';
        SELECT rowid FROM x1 WHERE x1 MATCH 'xd*';
        SELECT rowid FROM x1 WHERE x1 MATCH 'xe*';
        SELECT rowid FROM x1 WHERE x1 MATCH 'xf*';
        SELECT rowid FROM x1 WHERE x1 MATCH 'xg*';
        SELECT rowid FROM x1 WHERE x1 MATCH 'xh*';
        SELECT rowid FROM x1 WHERE x1 MATCH 'xi*';
      }
      set {} {}
    } {}
    catch { db eval ROLLBACK }
  }
}

}

#------------------------------------------------------------------------
#
reset_db
do_execsql_test 6.1.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(a);
  INSERT INTO t1 VALUES('bbbbb ccccc');
  SELECT quote(block) FROM t1_data WHERE rowid>100;
} {X'000000180630626262626201020201056363636363010203040A'}
do_execsql_test 6.1.1 {
  UPDATE t1_data SET block = 
  X'000000180630626262626201020201056161616161010203040A'
  WHERE rowid>100;
}
do_catchsql_test 6.1.2 {
  INSERT INTO t1(t1) VALUES('integrity-check');
} {1 {database disk image is malformed}}

#-------
reset_db
do_execsql_test 6.2.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(a);
  INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
  INSERT INTO t1 VALUES('aa bb cc dd ee');
  SELECT pgno, quote(term) FROM t1_idx;
} {2 X'' 4 X'3064'}
do_execsql_test 6.2.1 {
  UPDATE t1_idx SET term = X'3065' WHERE pgno=4;
}
do_catchsql_test 6.2.2 {
  INSERT INTO t1(t1) VALUES('integrity-check');
} {1 {database disk image is malformed}}

#-------
reset_db
do_execsql_test 6.3.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(a);
  INSERT INTO t1 VALUES('abc abcdef abcdefghi');
  SELECT quote(block) FROM t1_data WHERE id>100;
}    {X'0000001C043061626301020204036465660102030703676869010204040808'}
do_execsql_test 6.3.1 {
  BEGIN;
    UPDATE t1_data SET block = 
      X'0000001C043061626301020204036465660102035003676869010204040808'
      ------------------------------------------^^---------------------
    WHERE id>100;
}
do_catchsql_test 6.3.2 {
  INSERT INTO t1(t1) VALUES('integrity-check');
} {1 {database disk image is malformed}}
do_execsql_test 6.3.3 {
  ROLLBACK;
  BEGIN;
    UPDATE t1_data SET block = 
      X'0000001C043061626301020204036465660102030750676869010204040808'
      --------------------------------------------^^-------------------
    WHERE id>100;
}
do_catchsql_test 6.3.3 {
  INSERT INTO t1(t1) VALUES('integrity-check');
} {1 {database disk image is malformed}}
do_execsql_test 6.3.4 {
  ROLLBACK;
  BEGIN;
    UPDATE t1_data SET block = 
      X'0000001C043061626301020204036465660102030707676869010204040850'
      --------------------------------------------------------------^^-
    WHERE id>100;
}
do_catchsql_test 6.3.5 {
  INSERT INTO t1(t1) VALUES('integrity-check');
} {1 {database disk image is malformed}}
do_execsql_test 6.3.6 {
  ROLLBACK;
  BEGIN;
    UPDATE t1_data SET block = 
      X'0000001C503061626301020204036465660102030707676869010204040808'
      ----------^^-----------------------------------------------------
    WHERE id>100;
}
do_catchsql_test 6.3.5 {
  INSERT INTO t1(t1) VALUES('integrity-check');
} {1 {database disk image is malformed}}

sqlite3_fts5_may_be_corrupt 0
finish_test

  return
}

if { $tcl_platform(wordSize)<8 } {
  finish_test
  return
}

if 1 {

proc do_fb_test {tn sql res} {
  set res2 [lsort -integer -decr $res]
  uplevel [list do_execsql_test $tn.1 $sql $res]
  uplevel [list do_execsql_test $tn.2 "$sql ORDER BY rowid DESC" $res2]
}

  breakpoint
  do_execsql_test $tn.2 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'b AND a' ORDER BY rowid DESC
  } {1}
}

do_dlidx_test2 2.1 [expr 20] [expr 1<<57] [expr (1<<57) + 128]

}

#--------------------------------------------------------------------
#
reset_db

set ::vocab [list \
  IteratorpItercurrentlypointstothefirstrowidofadoclist \
  Thereisadoclistindexassociatedwiththefinaltermonthecurrent \
  pageIfthecurrenttermisthelasttermonthepageloadthe \
  doclistindexfromdiskandinitializeaniteratoratpIterpDlidx \
  IteratorpItercurrentlypointstothefirstrowidofadoclist \
  Thereisadoclistindexassociatedwiththefinaltermonthecurrent \
  pageIfthecurrenttermisthelasttermonthepageloadthe \
  doclistindexfromdiskandinitializeaniteratoratpIterpDlidx \
]
proc rnddoc {} {
  global vocab
  set nVocab [llength $vocab]
  set ret [list]
  for {set i 0} {$i < 64} {incr i} {
    lappend ret [lindex $vocab [expr $i % $nVocab]]
  }
  set ret
}
db func rnddoc rnddoc

do_execsql_test 3.1 {
  CREATE VIRTUAL TABLE abc USING fts5(a);
  INSERT INTO abc(abc, rank) VALUES('pgsz', 32);

  INSERT INTO abc VALUES ( rnddoc() );
  INSERT INTO abc VALUES ( rnddoc() );
  INSERT INTO abc VALUES ( rnddoc() );
  INSERT INTO abc VALUES ( rnddoc() );

  INSERT INTO abc SELECT rnddoc() FROM abc;
  INSERT INTO abc SELECT rnddoc() FROM abc;
}



do_execsql_test 3.2 {
  SELECT rowid FROM abc WHERE abc 
  MATCH 'IteratorpItercurrentlypointstothefirstrowidofadoclist' 
  ORDER BY rowid DESC;
} {16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1}

do_execsql_test 3.2 {
  INSERT INTO abc(abc) VALUES('integrity-check');
  INSERT INTO abc(abc) VALUES('optimize');
  INSERT INTO abc(abc) VALUES('integrity-check');
}

set v [lindex $vocab 0]
set i 0
foreach v $vocab {
  do_execsql_test 3.3.[incr i] {
    SELECT rowid FROM abc WHERE abc MATCH $v
  } {1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16}
}


finish_test

#-------------------------------------------------------------------------
# Experiment with a tokenizer that considers " to be a token character.
#
do_execsql_test 4.0 {
  SELECT fts5_expr('a AND """"', 'x', 'tokenize="unicode61 tokenchars ''""''"');
} {{"a" AND """"}}

#-------------------------------------------------------------------------
# Experiment with a tokenizer that considers " to be a token character.
#
do_catchsql_test 5.0 {
  SELECT fts5_expr('abc | def');
} {1 {fts5: syntax error near "|"}}



finish_test

proc do_syntax_test {tn expr res} {
  set ::se_expr $expr
  do_execsql_test $tn {SELECT fts5_expr($se_expr)} [list $res]
}

foreach {tn expr res} {
  1  {abc}                            {"abc"}
  2  {abc ""}                         {"abc"}
  3  {""}                             {}
  4  {abc OR ""}                      {"abc"}
  5  {abc NOT ""}                     {"abc"}
  6  {abc AND ""}                     {"abc"}
  7  {"" OR abc}                      {"abc"}
  8  {"" NOT abc}                     {"abc"}
  9  {"" AND abc}                     {"abc"}
  10 {abc + "" + def}                 {"abc" + "def"}
  11 {abc "" def}                     {"abc" AND "def"}
  12 {r+e OR w}                       {"r" + "e" OR "w"}
} {
  do_execsql_test 1.$tn {SELECT fts5_expr($expr)} [list $res]
}

do_catchsql_test 2.1 {
  SELECT fts5_expr()
} {1 {wrong number of arguments to function fts5_expr}}

set testprefix fts5fault6

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


#-------------------------------------------------------------------------
# OOM while rebuilding an FTS5 table.
#
do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE tt USING fts5(a, b);
  INSERT INTO tt VALUES('c d c g g f', 'a a a d g a');

  db eval { 
    CREATE VIRTUAL TABLE yu USING fts5(x, tokenize="unicode61 separators abc");
  }
} -test {
  faultsim_test_result {0 {}}
}

#-------------------------------------------------------------------------
#
# 5.2.* OOM while running a query that includes synonyms and matchinfo().
#
# 5.3.* OOM while running a query that returns a row containing instances
#       of more than 4 synonyms for a single term.
#
proc mit {blob} {
  set scan(littleEndian) i*
  set scan(bigEndian) I*
  binary scan $blob $scan($::tcl_platform(byteOrder)) r
  return $r
}
proc tcl_tokenize {tflags text} {
  foreach {w iStart iEnd} [fts5_tokenize_split $text] {
    sqlite3_fts5_token $w $iStart $iEnd
    if {$tflags=="query" && [string length $w]==1} {
      for {set i 2} {$i < 7} {incr i} {
        sqlite3_fts5_token -colo [string repeat $w $i] $iStart $iEnd
      }
    }
  }
}
proc tcl_create {args} { return "tcl_tokenize" }
reset_db
sqlite3_fts5_create_tokenizer db tcl tcl_create
db func mit mit
sqlite3_fts5_register_matchinfo db
do_test 5.0 {
  execsql { CREATE VIRTUAL TABLE t1 USING fts5(a, tokenize=tcl) }
  execsql { INSERT INTO t1(t1, rank) VALUES('pgsz', 32) }
  foreach {rowid text} {
    1 {aaaa cc b aaaaa cc aa} 
    2 {aa aa bb a bbb}
    3 {bb aaaaa aaaaa b aaaa aaaaa}
    4 {aa a b aaaa aa}
    5 {aa b ccc aaaaa cc}
    6 {aa aaaaa bbbb cc aaa}
    7 {aaaaa aa aa ccccc bb}
    8 {ccc bbbbb ccccc bbb c}
    9 {cccccc bbbb a aaa cccc c}

    20 {ddd f ddd eeeee fff ffff eeee ddd fff eeeee dddddd eeee}
    21 {fffff eee dddd fffff dd ee ee eeeee eee eeeeee ee dd e}
    22 {fffff d eeee dddd fffff dddddd ffff ddddd eeeee ee eee dddd ddddd}
    23 {ddddd fff ddd eeeee ffff eeee ddd ff ff ffffff eeeeee dddd ffffff}
    24 {eee dd ee dddd dddd eeeeee e eee fff ffff}
    25 {ddddd ffffff dddddd fff ddd ddddd ddd f eeee fff dddd f}
    26 {f ffff fff fff eeeeee dddd d dddddd ddddd eee ff eeeee}
    27 {eee fff dddddd eeeee eeeee dddd ddddd ffff f eeeee eee dddddd ddddd d}
    28 {dd ddddd d ddd d fff d dddd ee dddd ee ddd dddddd dddddd}
    29 {eeee dddd ee dddd eeee dddd dd fffff f ddd eeeee ddd ee}
    30 {ff ffffff eeeeee eeeee eee ffffff ff ffff f fffff eeeee}
    31 {fffff eeeeee dddd eeee eeee eeeeee eee fffff d ddddd ffffff ffff dddddd}
    32 {dddddd fffff ee eeeeee eeee ee fff dddd fff eeee ffffff eeeeee ffffff}
    33 {ddddd eeee dd ffff dddddd fff eeee ddddd ffff eeee ddd}
    34 {ee dddd ddddd dddddd eeee eeeeee f dd ee dddddd ffffff}
    35 {ee dddd dd eeeeee ddddd eee d eeeeee dddddd eee dddd fffff}
    36 {eee ffffff ffffff e fffff eeeee ff dddddd dddddd fff}
    37 {eeeee fffff dddddd dddd ffffff fff f dd ee dd dd eeeee}
    38 {eeeeee ee d ff eeeeee eeeeee eee eeeee ee ffffff dddd eeee dddddd ee}
    39 {eeeeee ddd fffff e dddd ee eee eee ffffff ee f d dddd}
    40 {ffffff dddddd eee ee ffffff eee eeee ddddd ee eeeeee f}
    41 {ddd ddd fff fffff ee fffff f fff ddddd fffff}
    42 {dddd ee ff d f ffffff fff ffffff ff dd dddddd f eeee}
    43 {d dd fff fffff d f fff e dddd ee ee}
    44 {ff ffff eee ddd d dd ffff dddd d eeee d eeeeee}
    45 {eeee f eeeee ee e ffff f ddd e fff}
    46 {ffff d ffff eeee ffff eeeee f ffff ddddd eee}
    47 {dd dd dddddd ddddd fffff dddddd ddd ddddd eeeeee ffff eeee eee ee}
    48 {ffff ffff e dddd ffffff dd dd dddd f fffff}
    49 {ffffff d dddddd ffff eeeee f ffff ffff d dd fffff eeeee}

    50 {x e}
  } {
    execsql { INSERT INTO t1(rowid, a) VALUES($rowid, $text) }
  }
} {}

set res [list {*}{
  1 {3 24 8 2 12 6}
  5 {2 24 8 2 12 6}
  6 {3 24 8 1 12 6}
  7 {3 24 8 1 12 6}
  9 {2 24 8 3 12 6}
}]
do_execsql_test 5.1.1 {
  SELECT rowid, mit(matchinfo(t1, 'x')) FROM t1 WHERE t1 MATCH 'a AND c'
} $res
do_execsql_test 5.1.2 {
  SELECT count(*) FROM t1 WHERE t1 MATCH 'd e f'
} 29

faultsim_save_and_close
do_faultsim_test 5.2 -faults oom* -prep {
  faultsim_restore_and_reopen
  sqlite3_fts5_create_tokenizer db tcl tcl_create
  sqlite3_fts5_register_matchinfo db
  db func mit mit
} -body {
  db eval { 
    SELECT rowid, mit(matchinfo(t1, 'x')) FROM t1 WHERE t1 MATCH 'a AND c'
  }
} -test {
  faultsim_test_result [list 0 $::res]
}

do_faultsim_test 5.3 -faults oom* -prep {
  faultsim_restore_and_reopen
  sqlite3_fts5_create_tokenizer db tcl tcl_create
} -body {
  db eval { 
    SELECT count(*) FROM t1 WHERE t1 MATCH 'd AND e AND f'
  }
} -test {
  faultsim_test_result {0 29}
}

do_faultsim_test 5.4 -faults oom* -prep {
  faultsim_restore_and_reopen
  sqlite3_fts5_create_tokenizer db tcl tcl_create
} -body {
  db eval { 
    SELECT count(*) FROM t1 WHERE t1 MATCH 'x + e'
  }
} -test {
  faultsim_test_result {0 1}
}

#-------------------------------------------------------------------------
catch { db close }
breakpoint
do_faultsim_test 6 -faults oom* -prep {
  sqlite_orig db test.db
  sqlite3_db_config_lookaside db 0 0 0
} -body {
  load_static_extension db fts5
} -test {
  faultsim_test_result {0 {}} {1 {initialization of fts5 failed: }}
  if {$testrc==0} {
    db eval { CREATE VIRTUAL TABLE temp.t1 USING fts5(x) }
  }
  db close
}
finish_test

# 2015 September 3
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#*************************************************************************
#
# This file is focused on OOM errors.
#

source [file join [file dirname [info script]] fts5_common.tcl]
source $testdir/malloc_common.tcl
set testprefix fts5fault7

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

if 1 {

#-------------------------------------------------------------------------
# Test fault-injection on a query that uses xColumnSize() on columnsize=0
# table.
#
do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(x, columnsize=0);
  INSERT INTO t1 VALUES('a b c d e f g');
  INSERT INTO t1 VALUES('a b c d');
  INSERT INTO t1 VALUES('a b c d e f g h i j');
}


fts5_aux_test_functions db
do_faultsim_test 1 -faults oom* -body {
  execsql { SELECT fts5_test_columnsize(t1) FROM t1 WHERE t1 MATCH 'b' }
} -test {
  faultsim_test_result {0 {7 4 10}} {1 SQLITE_NOMEM}
}

}

#-------------------------------------------------------------------------
# Test fault-injection when a segment is promoted.
#
do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE t2 USING fts5(a);
  INSERT INTO t2(t2, rank) VALUES('automerge', 0);
  INSERT INTO t2(t2, rank) VALUES('crisismerge', 4);
  INSERT INTO t2(t2, rank) VALUES('pgsz', 40);

  INSERT INTO t2 VALUES('a b c');
  INSERT INTO t2 VALUES('d e f');
  INSERT INTO t2 VALUES('f e d');
  INSERT INTO t2 VALUES('c b a');

  INSERT INTO t2 VALUES('a b c');
  INSERT INTO t2 VALUES('d e f');
  INSERT INTO t2 VALUES('f e d');
  INSERT INTO t2 VALUES('c b a');
} {}

faultsim_save_and_close
do_faultsim_test 1 -faults oom-t* -prep {
  faultsim_restore_and_reopen
  db eval {
    BEGIN;
    INSERT INTO t2 VALUES('c d c g g f');
    INSERT INTO t2 VALUES('c d g b f d');
    INSERT INTO t2 VALUES('c c f d e d');
    INSERT INTO t2 VALUES('e a f c e f');
    INSERT INTO t2 VALUES('c g f b b d');
    INSERT INTO t2 VALUES('d a g a b b');
    INSERT INTO t2 VALUES('e f a b c e');
    INSERT INTO t2 VALUES('e c a g c d');
    INSERT INTO t2 VALUES('g b d d e b');
    INSERT INTO t2 VALUES('e a d a e d');
  }
} -body {
  db eval COMMIT
} -test {
  faultsim_test_result {0 {}}
}

finish_test

   GROUP BY t10.rowid
   ORDER BY 1;
} {1 1 one 2 2 two 3 3 three}
  
#---------------------------------------------------------------------------
# Test the 'y' matchinfo flag
#

reset_db
sqlite3_fts5_register_matchinfo db
do_execsql_test 11.0 {
  CREATE VIRTUAL TABLE tt USING fts5(x, y);
  INSERT INTO tt VALUES('c d a c d d', 'e a g b d a');   -- 1
  INSERT INTO tt VALUES('c c g a e b', 'c g d g e c');   -- 2
  INSERT INTO tt VALUES('b e f d e g', 'b a c b c g');   -- 3
  INSERT INTO tt VALUES('a c f f g d', 'd b f d e g');   -- 4
  INSERT INTO tt VALUES('g a c f c f', 'd g g b c c');   -- 5
  INSERT INTO tt VALUES('g a c e b b', 'd b f b g g');   -- 6
  INSERT INTO tt VALUES('f d a a f c', 'e e a d c f');   -- 7

    SELECT rowid, mit(matchinfo(tt, 'b')) FROM tt WHERE tt MATCH $expr
  } $r2

  do_execsql_test 11.1.$tn.2  {
    SELECT rowid, mit(matchinfo(tt, 'b')) FROM tt WHERE tt MATCH $expr
  } $r2
}


#---------------------------------------------------------------------------
# Test the 'b' matchinfo flag
#

reset_db
sqlite3_fts5_register_matchinfo db
db func mit mit

do_test 12.0 {
  set cols [list]
  for {set i 0} {$i < 50} {incr i} { lappend cols "c$i" }
  execsql "CREATE VIRTUAL TABLE tt USING fts5([join $cols ,])"
} {}

do_execsql_test 12.1 {
  INSERT INTO tt (rowid, c4, c45) VALUES(1, 'abc', 'abc');
  SELECT mit(matchinfo(tt, 'b')) FROM tt WHERE tt MATCH 'abc';
} [list [list [expr 1<<4] [expr 1<<(45-32)]]]


finish_test

do_catchsql_test 1.1 {
  SELECT fts5_rowid()
} {1 {should be: fts5_rowid(subject, ....)}}

do_catchsql_test 1.2 {
  SELECT fts5_rowid('segment')
} {1 {should be: fts5_rowid('segment', segid, pgno))}}

do_execsql_test 1.3 {
  SELECT fts5_rowid('segment', 1, 1)
} {137438953473}

do_catchsql_test 1.4 {
  SELECT fts5_rowid('nosucharg');
} {1 {first arg to fts5_rowid() must be 'segment'}} 


#-------------------------------------------------------------------------
# Tests of the fts5_decode() function.
#
reset_db
do_execsql_test 2.1 { 

} $res

# This is really a corruption test...
#do_execsql_test 2.7 {
#  UPDATE x1_data SET block = X'';
#  SELECT count(fts5_decode(rowid, block)) FROM x1_data;
#} $res

do_execsql_test 2.8 {
  SELECT fts5_decode(fts5_rowid('segment', 1000, 1), X'AB')
} {corrupt}

#-------------------------------------------------------------------------
# Tests with very large tokens.
#
set strlist [list \
  "[string repeat x 400]"                       \
  "[string repeat x 300][string repeat w 100]"  \

# 2015 September 05
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#*************************************************************************
#

source [file join [file dirname [info script]] fts5_common.tcl]
set testprefix fts5simple

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

if 1 {
#-------------------------------------------------------------------------
#
set doc "x x [string repeat {y } 50]z z"
do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(x);
  INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
  BEGIN;
    INSERT INTO t1 VALUES($doc);
  COMMIT;
}

do_execsql_test 1.1 {
  INSERT INTO t1(t1) VALUES('integrity-check');
}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 2.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(x);
  INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
  INSERT INTO t1 VALUES('a b c');
  INSERT INTO t1 VALUES('d e f');
  INSERT INTO t1(t1) VALUES('optimize');
}

do_execsql_test 2.1 {
  INSERT INTO t1(t1) VALUES('integrity-check');
} {}


#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 3.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(x, prefix='1,2');
  INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
  BEGIN;
  INSERT INTO t1 VALUES('one');
  SELECT * FROM t1 WHERE t1 MATCH 'o*';
} {one}

do_execsql_test 3.1 {
  INSERT INTO t1(t1) VALUES('integrity-check');
} {}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 4.1 {
  CREATE VIRTUAL TABLE t11 USING fts5(content);
  INSERT INTO t11(t11, rank) VALUES('pgsz', 32);
  INSERT INTO t11 VALUES('another');
  INSERT INTO t11 VALUES('string');
  INSERT INTO t11 VALUES('of');
  INSERT INTO t11 VALUES('text');
}
do_test 4.2 {
  execsql { INSERT INTO t11(t11) VALUES('optimize') }
} {}
do_execsql_test 4.3 {
  INSERT INTO t11(t11) VALUES('integrity-check');
} {}

#db eval { SELECT fts5_decode(rowid, block) as x FROM t11_data } { puts $x }

#-------------------------------------------------------------------------
reset_db
set doc [string repeat "x y " 5]
do_execsql_test 5.1 {
  CREATE VIRTUAL TABLE yy USING fts5(content);
  INSERT INTO yy(yy, rank) VALUES('pgsz', 32);
  BEGIN;
    INSERT INTO yy VALUES($doc);
    INSERT INTO yy VALUES($doc);
    INSERT INTO yy VALUES($doc);
    INSERT INTO yy VALUES($doc);
    INSERT INTO yy VALUES($doc);
    INSERT INTO yy VALUES($doc);
    INSERT INTO yy VALUES($doc);
    INSERT INTO yy VALUES($doc);
  COMMIT;
}

do_execsql_test 5.2 {
  SELECT rowid FROM yy WHERE yy MATCH 'y' ORDER BY rowid ASC
} {1 2 3 4 5 6 7 8}

do_execsql_test 5.3 {
  SELECT rowid FROM yy WHERE yy MATCH 'y' ORDER BY rowid DESC
} {8 7 6 5 4 3 2 1}

#db eval { SELECT fts5_decode(rowid, block) as x FROM yy_data } { puts $x }

#-------------------------------------------------------------------------
reset_db
do_execsql_test 5.1 {
  CREATE VIRTUAL TABLE tt USING fts5(content);
  INSERT INTO tt(tt, rank) VALUES('pgsz', 32);
  INSERT INTO tt VALUES('aa');
}

do_execsql_test 5.2 {
  SELECT rowid FROM tt WHERE tt MATCH 'a*';
} {1}

do_execsql_test 5.3 {
  DELETE FROM tt;
  BEGIN;
    INSERT INTO tt VALUES('aa');
    INSERT INTO tt VALUES('ab');
  COMMIT;
} {}

do_execsql_test 5.4 {
  SELECT rowid FROM tt WHERE tt MATCH 'a*';
} {1 2}

}

do_execsql_test 5.5 {
  DELETE FROM tt;
  BEGIN;
    INSERT INTO tt VALUES('aa');
    INSERT INTO tt VALUES('ab');
    INSERT INTO tt VALUES('aa');
    INSERT INTO tt VALUES('ab');
    INSERT INTO tt VALUES('aa');
    INSERT INTO tt VALUES('ab');
    INSERT INTO tt VALUES('aa');
    INSERT INTO tt VALUES('ab');
  COMMIT;
  SELECT rowid FROM tt WHERE tt MATCH 'a*';
} {1 2 3 4 5 6 7 8}

do_execsql_test 5.6 {
  INSERT INTO tt(tt) VALUES('integrity-check');
}

reset_db
do_execsql_test 5.7 {
  CREATE VIRTUAL TABLE tt USING fts5(content);
  INSERT INTO tt(tt, rank) VALUES('pgsz', 32);
  INSERT INTO tt VALUES('aa ab ac ad ae af');
}

do_execsql_test 5.8 {
  SELECT rowid FROM tt WHERE tt MATCH 'a*';
} {1}

finish_test

# 2014 Dec 20
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# Tests focusing on custom tokenizers that support synonyms.
#

source [file join [file dirname [info script]] fts5_common.tcl]
set testprefix fts5synonym

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

foreach S {
  {zero 0}
  {one 1 i}
  {two 2 ii}
  {three 3 iii}
  {four 4 iv}
  {five 5 v}
  {six 6 vi}
  {seven 7 vii}
  {eight 8 viii}
  {nine 9 ix}
} {
  foreach s $S {
    set o [list]
    foreach x $S {if {$x!=$s} {lappend o $x}}
    set ::syn($s) $o
  }
}

proc tcl_tokenize {tflags text} {
  foreach {w iStart iEnd} [fts5_tokenize_split $text] {
    sqlite3_fts5_token $w $iStart $iEnd
  }
}

proc tcl_create {args} {
  return "tcl_tokenize"
}

sqlite3_fts5_create_tokenizer db tcl tcl_create

#-------------------------------------------------------------------------
# Warm body test for the code in fts5_tcl.c.
#
do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE ft USING fts5(x, tokenize = tcl);
  INSERT INTO ft VALUES('abc def ghi');
  INSERT INTO ft VALUES('jkl mno pqr');
  SELECT rowid, x FROM ft WHERE ft MATCH 'def';
  SELECT x, rowid FROM ft WHERE ft MATCH 'pqr';
} {1 {abc def ghi} {jkl mno pqr} 2}

#-------------------------------------------------------------------------
# Test a tokenizer that supports synonyms by adding extra entries to the
# FTS index.
#

proc tcl_tokenize {tflags text} {
  foreach {w iStart iEnd} [fts5_tokenize_split $text] {
    sqlite3_fts5_token $w $iStart $iEnd
    if {$tflags=="document" && [info exists ::syn($w)]} {
      foreach s $::syn($w) {
        sqlite3_fts5_token -colo $s $iStart $iEnd
      }
    }
  }
}
reset_db
sqlite3_fts5_create_tokenizer db tcl tcl_create

do_execsql_test 2.0 {
  CREATE VIRTUAL TABLE ft USING fts5(x, tokenize = tcl);
  INSERT INTO ft VALUES('one two three');
  INSERT INTO ft VALUES('four five six');
  INSERT INTO ft VALUES('eight nine ten');
} {}

foreach {tn expr res} {
  1 "3" 1
  2 "eight OR 8 OR 5" {2 3}
  3 "10" {}
  4 "1*" {1}
  5 "1 + 2" {1}
} {
  do_execsql_test 2.1.$tn {
    SELECT rowid FROM ft WHERE ft MATCH $expr
  } $res
}

#-------------------------------------------------------------------------
# Test some broken tokenizers:
#
#   3.1.*: A tokenizer that declares the very first token to be colocated.
#
#   3.2.*: A tokenizer that reports two identical tokens at the same position.
#          This is allowed.
#
reset_db
sqlite3_fts5_create_tokenizer db tcl tcl_create
proc tcl_tokenize {tflags text} {
  set bColo 1
  foreach {w iStart iEnd} [fts5_tokenize_split $text] {
    if {$bColo} {
      sqlite3_fts5_token -colo $w $iStart $iEnd
      set bColo 0
    } {
      sqlite3_fts5_token $w $iStart $iEnd
    }
  }
}
do_execsql_test 3.1.0 {
  CREATE VIRTUAL TABLE ft USING fts5(x, tokenize = tcl);
  INSERT INTO ft VALUES('one two three');
  CREATE VIRTUAL TABLE vv USING fts5vocab(ft, row);
  SELECT * FROM vv;
} {
  one 1 1   three 1 1   two 1 1
}

do_execsql_test 3.1.1 {
  INSERT INTO ft(ft) VALUES('integrity-check');
} {}

proc tcl_tokenize {tflags text} {
  foreach {w iStart iEnd} [fts5_tokenize_split $text] {
    sqlite3_fts5_token $w $iStart $iEnd
  }
}

do_execsql_test 3.1.2 {
  SELECT rowid FROM ft WHERE ft MATCH 'one two three'
} {1}

reset_db
sqlite3_fts5_create_tokenizer db tcl tcl_create
proc tcl_tokenize {tflags text} {
  foreach {w iStart iEnd} [fts5_tokenize_split $text] {
    sqlite3_fts5_token $w $iStart $iEnd
    sqlite3_fts5_token -colo $w $iStart $iEnd
  }
}
do_execsql_test 3.2.0 {
  CREATE VIRTUAL TABLE ft USING fts5(x, tokenize = tcl);
  INSERT INTO ft VALUES('one one two three');
  CREATE VIRTUAL TABLE vv USING fts5vocab(ft, row);
  SELECT * FROM vv;
} {
  one 1 4   three 1 2   two 1 2
}
do_execsql_test 3.2.1 {
  SELECT rowid FROM ft WHERE ft MATCH 'one';
} {1}
do_execsql_test 3.2.2 {
  SELECT rowid FROM ft WHERE ft MATCH 'one two three';
} {1}
do_execsql_test 3.2.3 {
  SELECT rowid FROM ft WHERE ft MATCH 'one + one + two + three';
} {1}
do_execsql_test 3.2.4 {
  SELECT rowid FROM ft WHERE ft MATCH 'one two two three';
} {1}
do_execsql_test 3.2.5 {
  SELECT rowid FROM ft WHERE ft MATCH 'one + two + two + three';
} {}

#-------------------------------------------------------------------------
# Check that expressions with synonyms can be parsed and executed.
#
reset_db
sqlite3_fts5_create_tokenizer db tcl tcl_create
proc tcl_tokenize {tflags text} {
  foreach {w iStart iEnd} [fts5_tokenize_split $text] {
    sqlite3_fts5_token $w $iStart $iEnd
    if {$tflags=="query" && [info exists ::syn($w)]} {
      foreach s $::syn($w) {
        sqlite3_fts5_token -colo $s $iStart $iEnd
      }
    }
  }
}

foreach {tn expr res} {
  1  {abc}                           {"abc"}
  2  {one}                           {"one"|"i"|"1"}
  3  {3}                             {"3"|"iii"|"three"}
  4  {3*}                            {"3"|"iii"|"three" *}
} {
  do_execsql_test 4.1.$tn {SELECT fts5_expr($expr, 'tokenize=tcl')} [list $res]
}

do_execsql_test 4.2.1 {
  CREATE VIRTUAL TABLE xx USING fts5(x, tokenize=tcl);
  INSERT INTO xx VALUES('one two');
  INSERT INTO xx VALUES('three four');
}

do_execsql_test 4.2.2 {
  SELECT rowid FROM xx WHERE xx MATCH '2'
} {1}

do_execsql_test 4.2.3 {
  SELECT rowid FROM xx WHERE xx MATCH '3'
} {2}

do_test 5.0 {
  execsql { 
    CREATE VIRTUAL TABLE t1 USING fts5(a, b, tokenize=tcl)
  }
  foreach {rowid a b} {
    1 {four v 4 i three} {1 3 five five 4 one}
    2 {5 1 3 4 i} {2 2 v two 4}
    3 {5 i 5 2 four 4 1} {iii ii five two 1}
    4 {ii four 4 one 5 three five} {one 5 1 iii 4 3}
    5 {three i v i four 4 1} {ii five five five iii}
    6 {4 2 ii two 2 iii} {three 1 four 4 iv 1 iv}
    7 {ii ii two three 2 5} {iii i ii iii iii one one}
    8 {2 ii i two 3 three 2} {two iv v iii 3 five}
    9 {i 2 iv 3 five four v} {iii 4 three i three ii 1}
  } {
    execsql { INSERT INTO t1(rowid, a, b) VALUES($rowid, $a, $b) }
  }
} {}


foreach {tn q res} {
  1 {one} {
    1 {four v 4 [i] three} {[1] 3 five five 4 [one]}
    2 {5 [1] 3 4 [i]} {2 2 v two 4}
    3 {5 [i] 5 2 four 4 [1]} {iii ii five two [1]}
    4 {ii four 4 [one] 5 three five} {[one] 5 [1] iii 4 3}
    5 {three [i] v [i] four 4 [1]} {ii five five five iii}
    6 {4 2 ii two 2 iii} {three [1] four 4 iv [1] iv}
    7 {ii ii two three 2 5} {iii [i] ii iii iii [one] [one]}
    8 {2 ii [i] two 3 three 2} {two iv v iii 3 five}
    9 {[i] 2 iv 3 five four v} {iii 4 three [i] three ii [1]}
  }
  2 {five four} {
    1 {[four] [v] [4] i three} {1 3 [five] [five] [4] one}
    2 {[5] 1 3 [4] i} {2 2 [v] two [4]}
    3 {[5] i [5] 2 [four] [4] 1} {iii ii [five] two 1}
    4 {ii [four] [4] one [5] three [five]} {one [5] 1 iii [4] 3}
    5 {three i [v] i [four] [4] 1} {ii [five] [five] [five] iii}
    8 {2 ii i two 3 three 2} {two [iv] [v] iii 3 [five]}
    9 {i 2 [iv] 3 [five] [four] [v]} {iii [4] three i three ii 1}
  }
  3 {one OR two OR iii OR 4 OR v} {
    1 {[four] [v] [4] [i] [three]} {[1] [3] [five] [five] [4] [one]}
    2 {[5] [1] [3] [4] [i]} {[2] [2] [v] [two] [4]}
    3 {[5] [i] [5] [2] [four] [4] [1]} {[iii] [ii] [five] [two] [1]}
    4 {[ii] [four] [4] [one] [5] [three] [five]} {[one] [5] [1] [iii] [4] [3]}
    5 {[three] [i] [v] [i] [four] [4] [1]} {[ii] [five] [five] [five] [iii]}
    6 {[4] [2] [ii] [two] [2] [iii]} {[three] [1] [four] [4] [iv] [1] [iv]}
    7 {[ii] [ii] [two] [three] [2] [5]} {[iii] [i] [ii] [iii] [iii] [one] [one]}
    8 {[2] [ii] [i] [two] [3] [three] [2]} {[two] [iv] [v] [iii] [3] [five]}
    9 {[i] [2] [iv] [3] [five] [four] [v]} {[iii] [4] [three] [i] [three] [ii] [1]}
  }

  4 {5 + 1} {
    2 {[5 1] 3 4 i} {2 2 v two 4} 
    3 {[5 i] 5 2 four 4 1} {iii ii five two 1} 
    4 {ii four 4 one 5 three five} {one [5 1] iii 4 3} 
    5 {three i [v i] four 4 1} {ii five five five iii}
  }

  5 {one + two + three} {
    7 {ii ii two three 2 5} {iii [i ii iii] iii one one}
    8 {2 ii [i two 3] three 2} {two iv v iii 3 five}
  }

  6 {"v v"} {
    1 {four v 4 i three} {1 3 [five five] 4 one}
    5 {three i v i four 4 1} {ii [five five five] iii}
  }
} {
  do_execsql_test 5.1.$tn {
    SELECT rowid, highlight(t1, 0, '[', ']'), highlight(t1, 1, '[', ']')
    FROM t1 WHERE t1 MATCH $q
  } $res
}

# Test that the xQueryPhrase() API works with synonyms.
#
proc mit {blob} {
  set scan(littleEndian) i*
  set scan(bigEndian) I*
  binary scan $blob $scan($::tcl_platform(byteOrder)) r
  return $r
}
db func mit mit
sqlite3_fts5_register_matchinfo db

foreach {tn q res} {
  1 {one} {
      1 {1 11 7 2 12 6}     2 {2 11 7 0 12 6} 
      3 {2 11 7 1 12 6}     4 {1 11 7 2 12 6} 
      5 {3 11 7 0 12 6}     6 {0 11 7 2 12 6} 
      7 {0 11 7 3 12 6}     8 {1 11 7 0 12 6} 
      9 {1 11 7 2 12 6}
  }
} {
  do_execsql_test 5.2.$tn {
    SELECT rowid, mit(matchinfo(t1, 'x')) FROM t1 WHERE t1 MATCH $q
  } $res
}


#-------------------------------------------------------------------------
# Test terms with more than 4 synonyms.
#
reset_db
sqlite3_fts5_create_tokenizer db tcl tcl_create
proc tcl_tokenize {tflags text} {
  foreach {w iStart iEnd} [fts5_tokenize_split $text] {
    sqlite3_fts5_token $w $iStart $iEnd
    if {$tflags=="query" && [string length $w]==1} {
      for {set i 2} {$i<=10} {incr i} {
        sqlite3_fts5_token -colo [string repeat $w $i] $iStart $iEnd
      }
    }
  }
}

do_execsql_test 6.0.1 {
  CREATE VIRTUAL TABLE t1 USING fts5(x, tokenize=tcl);
  INSERT INTO t1 VALUES('yy xx qq');
  INSERT INTO t1 VALUES('yy xx xx');
}
do_execsql_test 6.0.2 {
  SELECT * FROM t1 WHERE t1 MATCH 'NEAR(y q)';
} {{yy xx qq}}

do_test 6.0.3 {
  execsql { 
    CREATE VIRTUAL TABLE t2 USING fts5(a, b, tokenize=tcl)
  }
  foreach {rowid a b} {
    1 {yyyy vvvvv qq oo yyyyyy vvvv eee} {ffff uu r qq aaaa}
    2 {ww oooooo bbbbb ssssss mm} {ffffff yy iiii rr s ccc qqqqq}
    3 {zzzz llll gggggg cccc uu} {hhhhhh aaaa ppppp rr ee jjjj}
    4 {r f i rrrrrr ww hhh} {aa yyy t x aaaaa ii}
    5 {fffff mm vvvv ooo ffffff kkkk tttt} {cccccc bb e zzz d n}
    6 {iii dddd hh qqqq ddd ooo} {ttt d c b aaaaaa qqqq}
    7 {jjjj rrrr v zzzzz u tt t} {ppppp pp dddd mm hhh uuu}
    8 {gggg rrrrrr kkkk vvvv gggg jjjjjj b} {dddddd jj r w cccc wwwwww ss}
    9 {kkkkk qqq oooo e tttttt mmm} {e ss qqqqqq hhhh llllll gg}
  } {
    execsql { INSERT INTO t2(rowid, a, b) VALUES($rowid, $a, $b) }
  }
} {}

foreach {tn q res} {
  1 {a} {
    1 {yyyy vvvvv qq oo yyyyyy vvvv eee} {ffff uu r qq [aaaa]}
    3 {zzzz llll gggggg cccc uu} {hhhhhh [aaaa] ppppp rr ee jjjj}
    4 {r f i rrrrrr ww hhh} {[aa] yyy t x [aaaaa] ii}
    6 {iii dddd hh qqqq ddd ooo} {ttt d c b [aaaaaa] qqqq}
  }

  2 {a AND q} {
    1 {yyyy vvvvv [qq] oo yyyyyy vvvv eee} {ffff uu r [qq] [aaaa]}
    6 {iii dddd hh [qqqq] ddd ooo} {ttt d c b [aaaaaa] [qqqq]}
  }

  3 {o OR (q AND a)} {
    1 {yyyy vvvvv [qq] [oo] yyyyyy vvvv eee} {ffff uu r [qq] [aaaa]}
    2 {ww [oooooo] bbbbb ssssss mm} {ffffff yy iiii rr s ccc qqqqq}
    5 {fffff mm vvvv [ooo] ffffff kkkk tttt} {cccccc bb e zzz d n}
    6 {iii dddd hh [qqqq] ddd [ooo]} {ttt d c b [aaaaaa] [qqqq]}
    9 {kkkkk qqq [oooo] e tttttt mmm} {e ss qqqqqq hhhh llllll gg}
  }

  4 {NEAR(q y, 20)} {
    1 {[yyyy] vvvvv [qq] oo [yyyyyy] vvvv eee} {ffff uu r qq aaaa}
    2 {ww oooooo bbbbb ssssss mm} {ffffff [yy] iiii rr s ccc [qqqqq]}
  }
} {
  do_execsql_test 6.1.$tn.asc {
    SELECT rowid, highlight(t2, 0, '[', ']'), highlight(t2, 1, '[', ']')
    FROM t2 WHERE t2 MATCH $q
  } $res

  set res2 [list]
  foreach {rowid a b} $res {
    set res2 [concat [list $rowid $a $b] $res2]
  }

  do_execsql_test 6.1.$tn.desc {
    SELECT rowid, highlight(t2, 0, '[', ']'), highlight(t2, 1, '[', ']')
    FROM t2 WHERE t2 MATCH $q ORDER BY rowid DESC
  } $res2
}

do_execsql_test 6.2.1 {
  INSERT INTO t2(rowid, a, b) VALUES(13,
      'x xx xxx xxxx xxxxx xxxxxx xxxxxxx', 'y yy yyy yyyy yyyyy yyyyyy yyyyyyy'
  );
  SELECT rowid, highlight(t2, 0, '<', '>'), highlight(t2, 1, '(', ')')
  FROM t2 WHERE t2 MATCH 'x OR y'
} {
  1 {<yyyy> vvvvv qq oo <yyyyyy> vvvv eee} {ffff uu r qq aaaa}
  2 {ww oooooo bbbbb ssssss mm} {ffffff (yy) iiii rr s ccc qqqqq}
  4 {r f i rrrrrr ww hhh} {aa (yyy) t (x) aaaaa ii}
  13 {<x> <xx> <xxx> <xxxx> <xxxxx> <xxxxxx> <xxxxxxx>}
     {(y) (yy) (yyy) (yyyy) (yyyyy) (yyyyyy) (yyyyyyy)}
}

#-------------------------------------------------------------------------
# Test that the xColumnSize() API is not confused by colocated tokens.
#
reset_db
sqlite3_fts5_create_tokenizer db tcl tcl_create
fts5_aux_test_functions db
proc tcl_tokenize {tflags text} {
  foreach {w iStart iEnd} [fts5_tokenize_split $text] {
    sqlite3_fts5_token $w $iStart $iEnd
    if {[string length $w]==1} {
      for {set i 2} {$i<=10} {incr i} {
        sqlite3_fts5_token -colo [string repeat $w $i] $iStart $iEnd
      }
    }
  }
}

do_execsql_test 7.0.1 {
  CREATE VIRTUAL TABLE t1 USING fts5(a, b, columnsize=1, tokenize=tcl);
  INSERT INTO t1 VALUES('0 2 3', '4 5 6 7');
  INSERT INTO t1 VALUES('8 9', '0 0 0 0 0 0 0 0 0 0');
  SELECT fts5_test_columnsize(t1) FROM t1 WHERE t1 MATCH '000 AND 00 AND 0';
} {{3 4} {2 10}}

do_execsql_test 7.0.2 {
  INSERT INTO t1(t1) VALUES('integrity-check');
}

do_execsql_test 7.1.1 {
  CREATE VIRTUAL TABLE t2 USING fts5(a, b, columnsize=0, tokenize=tcl);
  INSERT INTO t2 VALUES('0 2 3', '4 5 6 7');
  INSERT INTO t2 VALUES('8 9', '0 0 0 0 0 0 0 0 0 0');
  SELECT fts5_test_columnsize(t2) FROM t2 WHERE t2 MATCH '000 AND 00 AND 0';
} {{3 4} {2 10}}

do_execsql_test 7.1.2 {
  INSERT INTO t2(t2) VALUES('integrity-check');
}

finish_test