*/
static int fts3FunctionArg(
  sqlite3_context *pContext,      /* SQL function call context */
  const char *zFunc,              /* Function name */
  sqlite3_value *pVal,            /* argv[0] passed to function */
  Fts3Cursor **ppCsr              /* OUT: Store cursor handle here */
){
  Fts3Cursor *pRet;
  if( sqlite3_value_type(pVal)!=SQLITE_BLOB 
   || sqlite3_value_bytes(pVal)!=sizeof(Fts3Cursor *)
  ){

    char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
    sqlite3_result_error(pContext, zErr, -1);
    sqlite3_free(zErr);
    return SQLITE_ERROR;
  }
  memcpy(&pRet, sqlite3_value_blob(pVal), sizeof(Fts3Cursor *));
  *ppCsr = pRet;
  return SQLITE_OK;
}

/*
** Implementation of the snippet() function for FTS3
*/
static void fts3SnippetFunc(
  sqlite3_context *pContext,      /* SQLite function call context */
................................................................................
  **
  ** The right-hand child of a NEAR node is always a phrase. The 
  ** left-hand child may be either a phrase or a NEAR node. There are
  ** no exceptions to this - it's the way the parser in fts3_expr.c works.
  */
  if( *pRc==SQLITE_OK 
   && pExpr->eType==FTSQUERY_NEAR 
   && pExpr->bEof==0
   && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
  ){
    Fts3Expr *p; 
    int nTmp = 0;                 /* Bytes of temp space */
    char *aTmp;                   /* Temp space for PoslistNearMerge() */

    /* Allocate temporary working space. */
    for(p=pExpr; p->pLeft; p=p->pLeft){

      nTmp += p->pRight->pPhrase->doclist.nList;
    }
    nTmp += p->pPhrase->doclist.nList;
    if( nTmp==0 ){
      res = 0;
    }else{
      aTmp = sqlite3_malloc(nTmp*2);
      if( !aTmp ){
        *pRc = SQLITE_NOMEM;
        res = 0;
      }else{
        char *aPoslist = p->pPhrase->doclist.pList;
        int nToken = p->pPhrase->nToken;

        for(p=p->pParent;res && p && p->eType==FTSQUERY_NEAR; p=p->pParent){
          Fts3Phrase *pPhrase = p->pRight->pPhrase;
          int nNear = p->nNear;
          res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
        }

        aPoslist = pExpr->pRight->pPhrase->doclist.pList;
        nToken = pExpr->pRight->pPhrase->nToken;
        for(p=pExpr->pLeft; p && res; p=p->pLeft){
          int nNear;
          Fts3Phrase *pPhrase;
          assert( p->pParent && p->pParent->pLeft==p );
          nNear = p->pParent->nNear;
          pPhrase = (
              p->eType==FTSQUERY_NEAR ? p->pRight->pPhrase : p->pPhrase
              );
          res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
        }
      }

      sqlite3_free(aTmp);
    }
  }

  return res;
}

/*
** This function is a helper function for sqlite3Fts3EvalTestDeferred().

*/
static int fts3FunctionArg(
  sqlite3_context *pContext,      /* SQL function call context */
  const char *zFunc,              /* Function name */
  sqlite3_value *pVal,            /* argv[0] passed to function */
  Fts3Cursor **ppCsr              /* OUT: Store cursor handle here */
){
  int rc = SQLITE_OK;
  if( sqlite3_value_subtype(pVal)==SQLITE_BLOB ){
    *ppCsr = *(Fts3Cursor**)sqlite3_value_blob(pVal);

  }else{
    char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
    sqlite3_result_error(pContext, zErr, -1);
    sqlite3_free(zErr);
    rc = SQLITE_ERROR;
  }


  return rc;
}

/*
** Implementation of the snippet() function for FTS3
*/
static void fts3SnippetFunc(
  sqlite3_context *pContext,      /* SQLite function call context */
................................................................................
  **
  ** The right-hand child of a NEAR node is always a phrase. The 
  ** left-hand child may be either a phrase or a NEAR node. There are
  ** no exceptions to this - it's the way the parser in fts3_expr.c works.
  */
  if( *pRc==SQLITE_OK 
   && pExpr->eType==FTSQUERY_NEAR 

   && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
  ){
    Fts3Expr *p; 
    int nTmp = 0;                 /* Bytes of temp space */
    char *aTmp;                   /* Temp space for PoslistNearMerge() */

    /* Allocate temporary working space. */
    for(p=pExpr; p->pLeft; p=p->pLeft){
      assert( p->pRight->pPhrase->doclist.nList>0 );
      nTmp += p->pRight->pPhrase->doclist.nList;
    }
    nTmp += p->pPhrase->doclist.nList;



    aTmp = sqlite3_malloc(nTmp*2);
    if( !aTmp ){
      *pRc = SQLITE_NOMEM;
      res = 0;
    }else{
      char *aPoslist = p->pPhrase->doclist.pList;
      int nToken = p->pPhrase->nToken;

      for(p=p->pParent;res && p && p->eType==FTSQUERY_NEAR; p=p->pParent){
        Fts3Phrase *pPhrase = p->pRight->pPhrase;
        int nNear = p->nNear;
        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
      }

      aPoslist = pExpr->pRight->pPhrase->doclist.pList;
      nToken = pExpr->pRight->pPhrase->nToken;
      for(p=pExpr->pLeft; p && res; p=p->pLeft){
        int nNear;
        Fts3Phrase *pPhrase;
        assert( p->pParent && p->pParent->pLeft==p );
        nNear = p->pParent->nNear;
        pPhrase = (
            p->eType==FTSQUERY_NEAR ? p->pRight->pPhrase : p->pPhrase
        );
        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
      }
    }

    sqlite3_free(aTmp);

  }

  return res;
}

/*
** This function is a helper function for sqlite3Fts3EvalTestDeferred().

} {1 {database disk image is malformed}}
do_execsql_test 4.5 {
  UPDATE t4_stat SET value = X'00C03EC0B204C0A608' WHERE id=0;
}
do_catchsql_test 4.6 {
  SELECT count(*) FROM t4 WHERE t4 MATCH '"a b c" OR "c a b"'
} {1 {database disk image is malformed}}






















































finish_test

} {1 {database disk image is malformed}}
do_execsql_test 4.5 {
  UPDATE t4_stat SET value = X'00C03EC0B204C0A608' WHERE id=0;
}
do_catchsql_test 4.6 {
  SELECT count(*) FROM t4 WHERE t4 MATCH '"a b c" OR "c a b"'
} {1 {database disk image is malformed}}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 5.0 {
  CREATE VIRTUAL TABLE t5 USING fts4;
  INSERT INTO t5 VALUES('a x x x x b x x x x c');
  INSERT INTO t5 VALUES('a x x x x b x x x x c');
  INSERT INTO t5 VALUES('a x x x x b x x x x c');
}
do_execsql_test 5.1 {
  SELECT rowid FROM t5 WHERE t5 MATCH 'a NEAR/4 b NEAR/4 c'
} {1 2 3}
do_execsql_test 5.2 {
  SELECT rowid FROM t5 WHERE t5 MATCH 'a NEAR/3 b NEAR/4 c'
} {}
do_execsql_test 5.3 {
  SELECT rowid FROM t5 WHERE t5 MATCH 'a NEAR/4 b NEAR/3 c'
} {}
do_execsql_test 5.4 {
  SELECT rowid FROM t5 WHERE t5 MATCH 'y NEAR/4 b NEAR/4 c'
} {}
do_execsql_test 5.5 {
  SELECT rowid FROM t5 WHERE t5 MATCH 'x OR a NEAR/3 b NEAR/3 c'
} {1 2 3}
do_execsql_test 5.5 {
  SELECT rowid FROM t5 WHERE t5 MATCH 'x OR y NEAR/3 b NEAR/3 c'
} {1 2 3}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 6.0 {
  CREATE VIRTUAL TABLE t6 USING fts4;

  BEGIN;
  WITH s(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<50000)
    INSERT INTO t6 SELECT 'x x x x x x x x x x x' FROM s;

  INSERT INTO t6 VALUES('x x x x x x x x x x x A');
  INSERT INTO t6 VALUES('x x x x x x x x x x x B');
  INSERT INTO t6 VALUES('x x x x x x x x x x x A');
  INSERT INTO t6 VALUES('x x x x x x x x x x x B');

  WITH s(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<50000)
    INSERT INTO t6 SELECT 'x x x x x x x x x x x' FROM s;
  COMMIT;
}
breakpoint
do_execsql_test 6.1 {
  SELECT rowid FROM t6 WHERE t6 MATCH 'b OR "x a"'
} {50001 50002 50003 50004}


finish_test