SQLite

    rc = sqlite3_step(pCsr->pStmt);
    if( rc==SQLITE_ROW ){
      rc = SQLITE_OK;
      CsrFlagClear(pCsr, FTS5CSR_REQUIRE_CONTENT);
    }else{
      rc = sqlite3_reset(pCsr->pStmt);
      if( rc==SQLITE_OK ){
        rc = FTS5_CORRUPT;
      }
    }
  }
  return rc;
}

static void fts5SetVtabError(Fts5Table *p, const char *zFormat, ...){

#define FTS5_DEFAULT_NEARDIST 10
#define FTS5_DEFAULT_RANK     "bm25"

/* Name of rank and rowid columns */
#define FTS5_RANK_NAME "rank"
#define FTS5_ROWID_NAME "rowid"

#ifdef SQLITE_DEBUG
# define FTS5_CORRUPT sqlite3Fts5Corrupt()
int sqlite3Fts5Corrupt(void);
#else
# define FTS5_CORRUPT SQLITE_CORRUPT_VTAB
#endif

/**************************************************************************
** Interface to code in fts5.c. 
*/
typedef struct Fts5Global Fts5Global;

int sqlite3Fts5GetTokenizer(

** The rowid for the doclist index associated with leaf page pgno of segment
** segid in index idx.
*/
#define FTS5_DOCLIST_IDX_ROWID(idx, segid, pgno) \
        FTS5_SEGMENT_ROWID(idx, segid, FTS5_SEGMENT_MAX_HEIGHT, pgno)

#ifdef SQLITE_DEBUG
int sqlite3Fts5Corrupt() { return SQLITE_CORRUPT_VTAB; }



#endif


/*
** Each time a blob is read from the %_data table, it is padded with this
** many zero bytes. This makes it easier to decode the various record formats
** without overreading if the records are corrupt.

/*
** An object of type Fts5SegWriter is used to write to segments.
*/
struct Fts5PageWriter {
  int pgno;                       /* Page number for this page */
  Fts5Buffer buf;                 /* Buffer containing page data */
  Fts5Buffer term;              /* Buffer containing previous term on page */
};
struct Fts5SegWriter {
  int iIdx;                       /* Index to write to */
  int iSegid;                     /* Segid to write to */
  int nWriter;                    /* Number of entries in aWriter */
  Fts5PageWriter *aWriter;        /* Array of PageWriter objects */
  i64 iPrevRowid;                 /* Previous docid written to current leaf */
  u8 bFirstRowidInDoclist;        /* True if next rowid is first in doclist */
  u8 bFirstRowidInPage;           /* True if next rowid is first in page */
  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 */
  Fts5Buffer dlidx;               /* Doclist index */
  i64 iDlidxPrev;                 /* Previous rowid appended to dlidx */
  int bDlidxPrevValid;            /* True if iDlidxPrev is valid */
};

}

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

  if( pWriter->bFirstTermInPage ){
    /* No term was written to this page. */
    assert( 0==fts5GetU16(&pPage->buf.p[2]) );
    fts5WriteBtreeNoTerm(p, pWriter);
  }

  /* Write the current page to the db. */
  iRowid = FTS5_SEGMENT_ROWID(pWriter->iIdx, pWriter->iSegid, 0, pPage->pgno);
  fts5DataWrite(p, iRowid, pPage->buf.p, pPage->buf.n);

  /* Initialize the next page. */
  fts5BufferZero(&pPage->buf);

  fts5BufferAppendBlob(&p->rc, &pPage->buf, 4, zero);
  pPage->pgno++;

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

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

/*
** Append term pTerm/nTerm to the segment being written by the writer passed
** as the second argument.
**
** If an error occurs, set the Fts5Index.rc error code. If an error has 

  Fts5PageWriter *pPage = &pWriter->aWriter[0];

  assert( pPage==0 || pPage->buf.n==0 || pPage->buf.n>4 );
  if( pPage && pPage->buf.n==0 ){
    /* Zero the first term and first docid fields */
    static const u8 zero[] = { 0x00, 0x00, 0x00, 0x00 };
    fts5BufferAppendBlob(&p->rc, &pPage->buf, 4, zero);
    assert( pWriter->bFirstTermInPage );
  }
  if( p->rc ) return;
  
  if( pWriter->bFirstTermInPage ){
    /* Update the "first term" field of the page header. */
    assert( pPage->buf.p[2]==0 && pPage->buf.p[3]==0 );
    fts5PutU16(&pPage->buf.p[2], pPage->buf.n);
    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
      ** byte longer than the longest prefix (pTerm/nTerm) shares with the
      ** previous term. 
      **
      ** Usually, the previous term is available in pPage->term. The exception
      ** is if this is the first term written in an incremental-merge step.
      ** In this case the previous term is not available, so just write a
      ** copy of (pTerm/nTerm) into the parent node. This is slightly
      ** inefficient, but still correct.  */
      int n = nTerm;
      if( pPage->term.n ){
        n = 1 + fts5PrefixCompress(pPage->term.n, pPage->term.p, nTerm, pTerm);
      }
      fts5WriteBtreeTerm(p, pWriter, n, pTerm);
      pPage = &pWriter->aWriter[0];
    }
  }else{
    nPrefix = fts5PrefixCompress(pPage->term.n, pPage->term.p, nTerm, pTerm);


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

  /* Append the number of bytes of new data, then the term data itself
  ** to the page. */
  fts5BufferAppendVarint(&p->rc, &pPage->buf, nTerm - nPrefix);
  fts5BufferAppendBlob(&p->rc, &pPage->buf, nTerm - nPrefix, &pTerm[nPrefix]);

  /* Update the Fts5PageWriter.term field. */
  fts5BufferSet(&p->rc, &pPage->term, nTerm, pTerm);
  pWriter->bFirstTermInPage = 0;

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

  /* If the current leaf page is full, flush it to disk. */
  if( pPage->buf.n>=p->pConfig->pgsz ){
    fts5WriteFlushLeaf(p, pWriter);

  pWriter->iIdx = iIdx;
  pWriter->iSegid = iSegid;

  pWriter->aWriter = (Fts5PageWriter*)fts5IdxMalloc(p,sizeof(Fts5PageWriter));
  if( pWriter->aWriter==0 ) return;
  pWriter->nWriter = 1;
  pWriter->aWriter[0].pgno = 1;
  pWriter->bFirstTermInPage = 1;
}

static void fts5WriteInitForAppend(
  Fts5Index *p,                   /* FTS5 backend object */
  Fts5SegWriter *pWriter,         /* Writer to initialize */
  int iIdx,                       /* Index segment is a part of */
  Fts5StructureSegment *pSeg      /* Segment object to append to */

        fts5NodeIterFree(&ss);
      }
    }
    if( pSeg->nHeight==1 ){
      pWriter->nEmpty = pSeg->pgnoLast-1;
    }
    assert( (pgno+pWriter->nEmpty)==pSeg->pgnoLast );
    pWriter->bFirstTermInPage = 1;
    assert( pWriter->aWriter[0].term.n==0 );
  }
}

/*
** Iterator pIter was used to iterate through the input segments of on an
** incremental merge operation. This function is called if the incremental
** merge step has finished but the input has not been completely exhausted.

** error, or some other SQLite error code if another error (e.g. OOM)
** occurs.
*/
int sqlite3Fts5IndexIntegrityCheck(Fts5Index *p, u64 cksum){
  Fts5Config *pConfig = p->pConfig;
  int iIdx;                       /* Used to iterate through indexes */
  u64 cksum2 = 0;                 /* Checksum based on contents of indexes */

  /* Check that the internal nodes of each segment match the leaves */
  for(iIdx=0; p->rc==SQLITE_OK && iIdx<=pConfig->nPrefix; iIdx++){
    Fts5Structure *pStruct = fts5StructureRead(p, iIdx);
    if( pStruct ){
      int iLvl, iSeg;
      for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
        for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
          Fts5StructureSegment *pSeg = &pStruct->aLevel[iLvl].aSeg[iSeg];
          fts5IndexIntegrityCheckSegment(p, iIdx, pSeg);
        }
      }
    }
    fts5StructureRelease(pStruct);
  }

  /* Check that the checksum of the index matches the argument checksum */
  for(iIdx=0; iIdx<=pConfig->nPrefix; iIdx++){
    Fts5MultiSegIter *pIter;
    Fts5Structure *pStruct = fts5StructureRead(p, iIdx);
    for(fts5MultiIterNew(p, pStruct, iIdx, 0, 0, 0, 0, -1, 0, &pIter);
        fts5MultiIterEof(p, pIter)==0;

      }
    }
    fts5MultiIterFree(p, pIter);
    fts5StructureRelease(pStruct);
  }
  if( p->rc==SQLITE_OK && cksum!=cksum2 ) p->rc = FTS5_CORRUPT;
















  return fts5IndexReturn(p);
}


/*
** Indicate that all subsequent calls to sqlite3Fts5IndexWrite() pertain
** to the document with rowid iRowid.

    apNew = (Fts5Hash**)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Hash*)*nHash);
    for(i=0; rc==SQLITE_OK && i<nHash; i++){
      rc = sqlite3Fts5HashNew(&apNew[i], &p->nPendingData);
    }
    if( rc==SQLITE_OK ){
      p->apHash = apNew;
    }else{
      if( apNew ){
        for(i=0; i<nHash; i++){
          sqlite3Fts5HashFree(apNew[i]);
        }
        sqlite3_free(apNew);
      }
      return rc;
    }
  }

  if( iRowid<=p->iWriteRowid || (p->nPendingData > p->nMaxPendingData) ){
    fts5IndexFlush(p);
  }

        rc = sqlite3Fts5Tokenize(
            pConfig, 
            (const char*)sqlite3_column_text(pScan, i+1),
            sqlite3_column_bytes(pScan, i+1),
            (void*)&ctx,
            fts5StorageIntegrityCallback
        );
        if( 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;
  }

  /* Test that the "totals" (sometimes called "averages") record looks Ok */
  if( rc==SQLITE_OK ){
    int i;
    rc = fts5StorageLoadTotals(p, 0);
    for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
      if( p->aTotalSize[i]!=aTotalSize[i] ) rc = FTS5_CORRUPT;
    }
  }

  /* 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 ){
    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
  ** inspecting the index itself.  */
  if( rc==SQLITE_OK ){
    rc = sqlite3Fts5IndexIntegrityCheck(p->pIndex, ctx.cksum);

      int nBlob = sqlite3_column_bytes(pLookup, 0);
      if( 0==fts5StorageDecodeSizeArray(aCol, nCol, aBlob, nBlob) ){
        bCorrupt = 0;
      }
    }
    rc = sqlite3_reset(pLookup);
    if( bCorrupt && rc==SQLITE_OK ){
      rc = FTS5_CORRUPT;
    }
  }
  return rc;
}

int sqlite3Fts5StorageSize(Fts5Storage *p, int iCol, i64 *pnToken){
  int rc = fts5StorageLoadTotals(p, 0);

  set sql "SELECT fts5_decode(rowid,block) aS r FROM ${tbl}_data WHERE rowid=10"
  set ret [list]
  foreach L [lrange [db one $sql] 1 end] {
    lappend ret [expr [llength $L] - 2]
  }
  set ret
} 

proc fts5_level_segids {tbl} {
  set sql "SELECT fts5_decode(rowid,block) aS r FROM ${tbl}_data WHERE rowid=10"
  set ret [list]
  foreach L [lrange [db one $sql] 1 end] {
    set lvl [list]
    foreach S [lrange $L 2 end] {
      regexp {id=([1234567890]*)} $S -> segid
      lappend lvl $segid
    }
    lappend ret $lvl
  }
  set ret
}

proc fts5_rnddoc {n} {
  set map [list 0 a  1 b  2 c  3 d  4 e  5 f  6 g  7 h  8 i  9 j]
  set doc [list]
  for {set i 0} {$i < $n} {incr i} {
    lappend doc "x[string map $map [format %.3d [expr int(rand()*1000)]]]"
  }

# 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.
#
#***********************************************************************
#
#

source [file join [file dirname [info script]] fts5_common.tcl]
set testprefix fts5corrupt

do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(x);
  INSERT INTO t1(t1, rank) VALUES('pgsz', 32);
}

do_test 1.1 {
  db transaction {
    for {set i 1} {$i < 200} {incr i} {
      set doc [list [string repeat x $i] [string repeat y $i]]
      execsql { INSERT INTO t1(rowid, x) VALUES($i, $doc) }
    }
  }
  fts5_level_segs t1
} {1}
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', 0, $segid, 0, 4);
  }
  catchsql { INSERT INTO t1(t1) VALUES('integrity-check') }
} {1 {SQL logic error or missing database}}

do_test 1.4 {
  db_restore_and_reopen
  execsql {
    UPDATE t1_data set block = X'00000000' || substr(block, 5) WHERE
    rowid = fts5_rowid('segment', 0, $segid, 0, 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}



#--------------------------------------------------------------------
do_execsql_test 2.0 {
  CREATE VIRTUAL TABLE t2 USING fts5(x);
  INSERT INTO t2(t2, rank) VALUES('pgsz', 32);
}
do_test 2.1 {
  db transaction {
    for {set i 0} {$i < 20} {incr i} {
      execsql { INSERT INTO t2 VALUES('xxxxxxxxxx') }
    }
    for {set i 0} {$i < 20} {incr i} {
      execsql { INSERT INTO t2 VALUES('xxxxxxxxxzzzz') }
    }
  }
} {}
db eval {SELECT rowid, fts5_decode(rowid, block) aS r FROM t2_data} {puts $r}

finish_test