SQLite

  Fts5Tokenizer *pTok;
  fts5_tokenizer *pTokApi;

  /* Values loaded from the %_config table */
  int iCookie;                    /* Incremented when %_config is modified */
  int pgsz;                       /* Approximate page size used in %_data */
  int nAutomerge;                 /* 'automerge' setting */
  int nCrisisMerge;               /* Maximum allowed segments per level */
  char *zRank;                    /* Name of rank function */
  char *zRankArgs;                /* Arguments to rank function */
};

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

** This is an SQLite module implementing full-text search.
*/

#include "fts5Int.h"

#define FTS5_DEFAULT_PAGE_SIZE   1000
#define FTS5_DEFAULT_AUTOMERGE      4
#define FTS5_DEFAULT_CRISISMERGE   16

/* Maximum allowed page size */
#define FTS5_MAX_PAGE_SIZE (128*1024)

static int fts5_iswhitespace(char x){
  return (x==' ');
}

    if( nAutomerge<0 || nAutomerge>64 ){
      if( pbBadkey ) *pbBadkey = 1;
    }else{
      if( nAutomerge==1 ) nAutomerge = FTS5_DEFAULT_AUTOMERGE;
      pConfig->nAutomerge = nAutomerge;
    }
  }

  else if( 0==sqlite3_stricmp(zKey, "crisismerge") ){
    int nCrisisMerge = -1;
    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
      nCrisisMerge = sqlite3_value_int(pVal);
    }
    if( nCrisisMerge<0 ){
      if( pbBadkey ) *pbBadkey = 1;
    }else{
      if( nCrisisMerge<=1 ) nCrisisMerge = FTS5_DEFAULT_CRISISMERGE;
      pConfig->nCrisisMerge = nCrisisMerge;
    }
  }

  else if( 0==sqlite3_stricmp(zKey, "rank") ){
    const char *zIn = (const char*)sqlite3_value_text(pVal);
    char *zRank;
    char *zRankArgs;
    rc = sqlite3Fts5ConfigParseRank(zIn, &zRank, &zRankArgs);
    if( rc==SQLITE_OK ){

  char *zSql;
  sqlite3_stmt *p = 0;
  int rc;

  /* Set default values */
  pConfig->pgsz = FTS5_DEFAULT_PAGE_SIZE;
  pConfig->nAutomerge = FTS5_DEFAULT_AUTOMERGE;
  pConfig->nCrisisMerge = FTS5_DEFAULT_CRISISMERGE;

  zSql = sqlite3_mprintf(zSelect, pConfig->zDb, pConfig->zName);
  if( zSql==0 ){
    rc = SQLITE_NOMEM;
  }else{
    rc = sqlite3_prepare_v2(pConfig->db, zSql, -1, &p, 0);
    sqlite3_free(zSql);

**   * extra fields in the "structure record" record the state of ongoing
**     incremental merge operations.
**
*/

#define FTS5_OPT_WORK_UNIT  1000  /* Number of leaf pages per optimize step */
#define FTS5_WORK_UNIT      64    /* Number of leaf pages in unit of work */


#define FTS5_MIN_DLIDX_SIZE  4    /* Add dlidx if this many empty pages */

/*
** Details:
**
** The %_data table managed by this module,

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

  int nWorkUnit;                  /* Leaf pages in a "unit" of work */

  /*
  ** Variables related to the accumulation of tokens and doclists within the
  ** in-memory hash tables before they are flushed to disk.
  */
  Fts5Hash **apHash;              /* Array of hash tables */

  int iCookie;                    /* Configuration cookie */

  assert( iIdx<=pConfig->nPrefix );
  pData = fts5DataRead(p, FTS5_STRUCTURE_ROWID(iIdx));
  if( !pData ) return 0;
  p->rc = fts5StructureDecode(pData->p, pData->n, &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;
  }

  Fts5Structure *pStruct          /* Index structure */
){
  if( p->rc==SQLITE_OK ){
    int iTst;
    int iPromote = -1;
    int szPromote;                /* Promote anything this size or smaller */
    Fts5StructureSegment *pSeg;   /* Segment just written */

    int szSeg;                    /* Size of segment just written */


    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;
      int szMax = 0;
      Fts5StructureLevel *pTst = &pStruct->aLevel[iTst];
      assert( pTst->nMerge==0 );
      for(i=0; i<pTst->nSeg; i++){
        int sz = pTst->aSeg[i].pgnoLast - pTst->aSeg[i].pgnoFirst + 1;
        if( sz>szMax ) szMax = sz;
      }
      if( szMax>=szSeg ){
        /* Condition (a) is true. Promote the newest segment on level 
        ** iLvl to level iTst.  */

** Return true if the position iterator passed as the second argument is
** at EOF. Or if an error has already occurred. Otherwise, return false.
*/
static int fts5PosIterEof(Fts5Index *p, Fts5PosIter *pIter){
  return (p->rc || pIter->chunk.pLeaf==0);
}























/*
** Allocate a new segment-id for the structure pStruct.
**
** If an error has already occurred, this function is a no-op. 0 is 
** returned in this case.
*/
static int fts5AllocateSegid(Fts5Index *p, Fts5Structure *pStruct){

  int iIdx,                       /* Index to work on */
  Fts5Structure **ppStruct        /* IN/OUT: Current structure of index */
){
  Fts5Structure *pStruct = *ppStruct;
  int iLvl = 0;
  while( p->rc==SQLITE_OK 
      && iLvl<pStruct->nLevel
      && pStruct->aLevel[iLvl].nSeg>=p->pConfig->nCrisisMerge 
  ){
    fts5IndexMergeLevel(p, iIdx, &pStruct, iLvl, 0);
    fts5StructurePromote(p, iLvl+1, pStruct);
    iLvl++;
  }
  *ppStruct = pStruct;
}

/*
** Indicate that all subsequent calls to sqlite3Fts5IndexWrite() pertain
** to the document with rowid iRowid.
*/
int sqlite3Fts5IndexBeginWrite(Fts5Index *p, i64 iRowid){
  assert( p->rc==SQLITE_OK );

  /* Allocate hash tables if they have not already been allocated */
  if( p->apHash==0 ){
    int i;
    int rc = SQLITE_OK;
    int nHash = p->pConfig->nPrefix + 1;
    Fts5Hash **apNew;

    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{
      for(i=0; i<nHash; i++){
        sqlite3Fts5HashFree(apNew[i]);
      }
      sqlite3_free(apNew);
      return rc;
    }
  }

  if( iRowid<=p->iWriteRowid || (p->nPendingData > p->nMaxPendingData) ){
    fts5IndexFlush(p);
  }
  p->iWriteRowid = iRowid;
  return fts5IndexReturn(p);
}

  Fts5Index *p;                   /* New object */

  *pp = p = (Fts5Index*)sqlite3_malloc(sizeof(Fts5Index));
  if( !p ) return SQLITE_NOMEM;

  memset(p, 0, sizeof(Fts5Index));
  p->pConfig = pConfig;

  p->nWorkUnit = FTS5_WORK_UNIT;
  p->nMaxPendingData = 1024*1024;
  p->zDataTbl = sqlite3_mprintf("%s_data", pConfig->zName);
  if( p->zDataTbl==0 ){
    rc = SQLITE_NOMEM;
  }else if( bCreate ){
    rc = sqlite3Fts5CreateTable(

int sqlite3Fts5IndexWrite(
  Fts5Index *p,                   /* Index to write to */
  int iCol,                       /* Column token appears in (-ve -> delete) */
  int iPos,                       /* Position of token within column */
  const char *pToken, int nToken  /* Token to add or remove to or from index */
){
  int i;                          /* Used to iterate through indexes */
  int rc;                         /* Return code */
  Fts5Config *pConfig = p->pConfig;






  assert( p->rc==SQLITE_OK );




  /* Add the new token to the main terms hash table. And to each of the
  ** prefix hash tables that it is large enough for. */
  rc = sqlite3Fts5HashWrite(
      p->apHash[0], p->iWriteRowid, iCol, iPos, pToken, nToken
  );
  for(i=0; i<pConfig->nPrefix && rc==SQLITE_OK; i++){
    int nByte = fts5IndexCharlenToBytelen(pToken, nToken, pConfig->aPrefix[i]);
    if( nByte ){
      rc = sqlite3Fts5HashWrite(
          p->apHash[i+1], p->iWriteRowid, iCol, iPos, pToken, nByte
      );
    }
  }

  return rc;
}

/*
** Open a new iterator to iterate though all docids that match the 
** specified token or token prefix.
*/
int sqlite3Fts5IndexQuery(

  puts stderr ""
  puts stderr "Switches are:"
  puts stderr "  -fts4        (use fts4 instead of fts5)"
  puts stderr "  -fts5        (use fts5)"
  puts stderr "  -porter      (use porter tokenizer)"
  puts stderr "  -limit N     (load no more than N documents)"
  puts stderr "  -automerge N (set the automerge parameter to N)"
  puts stderr "  -crisismerge N (set the crisismerge parameter to N)"
  exit 1
}

set O(vtab)       fts5
set O(tok)        ""
set O(limit)      0
set O(automerge)  -1
set O(crisismerge)  -1

if {[llength $argv]<2} usage
set nOpt [expr {[llength $argv]-2}]
for {set i 0} {$i < $nOpt} {incr i} {
  set arg [lindex $argv $i]
  switch -- [lindex $argv $i] {
    -fts4 {

      set O(limit) [lindex $argv $i]
    }
    
    -automerge {
      if { [incr i]>=$nOpt } usage
      set O(automerge) [lindex $argv $i]
    }

    -crisismerge {
      if { [incr i]>=$nOpt } usage
      set O(crisismerge) [lindex $argv $i]
    }

    default {
      usage
    }
  }
}

sqlite3 db [lindex $argv end-1]
db func loadfile loadfile

db transaction {
  db eval "CREATE VIRTUAL TABLE t1 USING $O(vtab) (path, content$O(tok))"
  if {$O(automerge)>=0} {
    if {$O(vtab) == "fts5"} {
      db eval { INSERT INTO t1(t1, rank) VALUES('automerge', $O(automerge)) }
    } else {
      db eval { INSERT INTO t1(t1) VALUES('automerge=' || $O(automerge)) }
    }
  }
  if {$O(crisismerge)>=0} {
    if {$O(vtab) == "fts5"} {
      db eval {INSERT INTO t1(t1, rank) VALUES('crisismerge', $O(crisismerge))}
    } else {
    }
  }
  load_hierachy [lindex $argv end]
}