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Overview
Comment:Performance optimization in the tokenizer/parser loop.
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SHA1: 2cb71583d631cd417acbeebbb4ee950573a9deef
User & Date: drh 2017-03-07 14:38:52.463
Context
2017-03-07
20:03
Add test script ext/rbu/rbu_round_trip.tcl. Uses "dbselftest" to test that "rbu" and "sqldiff" work together. (check-in: 961e79da73 user: dan tags: trunk)
14:38
Performance optimization in the tokenizer/parser loop. (check-in: 2cb71583d6 user: drh tags: trunk)
12:18
Minor comment typo fixes. No changes to code. (check-in: 01cd9fb176 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/tokenize.c.
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** passed in.  An SQLITE_ status code is returned.  If an error occurs
** then an and attempt is made to write an error message into 
** memory obtained from sqlite3_malloc() and to make *pzErrMsg point to that
** error message.
*/
int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzErrMsg){
  int nErr = 0;                   /* Number of errors encountered */
  int i;                          /* Loop counter */
  void *pEngine;                  /* The LEMON-generated LALR(1) parser */

  int tokenType;                  /* type of the next token */
  int lastTokenParsed = -1;       /* type of the previous token */
  sqlite3 *db = pParse->db;       /* The database connection */
  int mxSqlLen;                   /* Max length of an SQL string */
#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
  unsigned char zSpace[sizeof(yyParser)];  /* Space for parser engine object */
#endif

  assert( zSql!=0 );
  mxSqlLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
  if( db->nVdbeActive==0 ){
    db->u1.isInterrupted = 0;
  }
  pParse->rc = SQLITE_OK;
  pParse->zTail = zSql;
  i = 0;
  assert( pzErrMsg!=0 );
  /* sqlite3ParserTrace(stdout, "parser: "); */
#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
  pEngine = zSpace;
  sqlite3ParserInit(pEngine);
#else
  pEngine = sqlite3ParserAlloc(sqlite3Malloc);
  if( pEngine==0 ){
    sqlite3OomFault(db);
    return SQLITE_NOMEM_BKPT;
  }
#endif
  assert( pParse->pNewTable==0 );
  assert( pParse->pNewTrigger==0 );
  assert( pParse->nVar==0 );
  assert( pParse->pVList==0 );
  while( 1 ){
    assert( i>=0 );
    if( zSql[i]!=0 ){
      pParse->sLastToken.z = &zSql[i];
      pParse->sLastToken.n = sqlite3GetToken((u8*)&zSql[i],&tokenType);
      i += pParse->sLastToken.n;
      if( i>mxSqlLen ){

        pParse->rc = SQLITE_TOOBIG;
        break;
      }
    }else{
      /* Upon reaching the end of input, call the parser two more times
      ** with tokens TK_SEMI and 0, in that order. */
      if( lastTokenParsed==TK_SEMI ){
        tokenType = 0;
      }else if( lastTokenParsed==0 ){
        break;
      }else{
        tokenType = TK_SEMI;
      }

    }
    if( tokenType>=TK_SPACE ){
      assert( tokenType==TK_SPACE || tokenType==TK_ILLEGAL );
      if( db->u1.isInterrupted ){
        pParse->rc = SQLITE_INTERRUPT;
        break;
      }
      if( tokenType==TK_ILLEGAL ){
        sqlite3ErrorMsg(pParse, "unrecognized token: \"%T\"",
                        &pParse->sLastToken);
        break;
      }

    }else{


      sqlite3Parser(pEngine, tokenType, pParse->sLastToken, pParse);
      lastTokenParsed = tokenType;

      if( pParse->rc!=SQLITE_OK || db->mallocFailed ) break;
    }
  }
  assert( nErr==0 );
  pParse->zTail = &zSql[i];
#ifdef YYTRACKMAXSTACKDEPTH
  sqlite3_mutex_enter(sqlite3MallocMutex());
  sqlite3StatusHighwater(SQLITE_STATUS_PARSER_STACK,
      sqlite3ParserStackPeak(pEngine)
  );
  sqlite3_mutex_leave(sqlite3MallocMutex());
#endif /* YYDEBUG */








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** passed in.  An SQLITE_ status code is returned.  If an error occurs
** then an and attempt is made to write an error message into 
** memory obtained from sqlite3_malloc() and to make *pzErrMsg point to that
** error message.
*/
int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzErrMsg){
  int nErr = 0;                   /* Number of errors encountered */

  void *pEngine;                  /* The LEMON-generated LALR(1) parser */
  int n = 0;                      /* Length of the next token token */
  int tokenType;                  /* type of the next token */
  int lastTokenParsed = -1;       /* type of the previous token */
  sqlite3 *db = pParse->db;       /* The database connection */
  int mxSqlLen;                   /* Max length of an SQL string */
#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
  unsigned char zSpace[sizeof(yyParser)];  /* Space for parser engine object */
#endif

  assert( zSql!=0 );
  mxSqlLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
  if( db->nVdbeActive==0 ){
    db->u1.isInterrupted = 0;
  }
  pParse->rc = SQLITE_OK;
  pParse->zTail = zSql;

  assert( pzErrMsg!=0 );
  /* sqlite3ParserTrace(stdout, "parser: "); */
#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
  pEngine = zSpace;
  sqlite3ParserInit(pEngine);
#else
  pEngine = sqlite3ParserAlloc(sqlite3Malloc);
  if( pEngine==0 ){
    sqlite3OomFault(db);
    return SQLITE_NOMEM_BKPT;
  }
#endif
  assert( pParse->pNewTable==0 );
  assert( pParse->pNewTrigger==0 );
  assert( pParse->nVar==0 );
  assert( pParse->pVList==0 );
  while( 1 ){

    if( zSql[0]!=0 ){

      n = sqlite3GetToken((u8*)zSql, &tokenType);

      mxSqlLen -= n;
      if( mxSqlLen<0 ){
        pParse->rc = SQLITE_TOOBIG;
        break;
      }
    }else{
      /* Upon reaching the end of input, call the parser two more times
      ** with tokens TK_SEMI and 0, in that order. */
      if( lastTokenParsed==TK_SEMI ){
        tokenType = 0;
      }else if( lastTokenParsed==0 ){
        break;
      }else{
        tokenType = TK_SEMI;
      }
      zSql -= n;
    }
    if( tokenType>=TK_SPACE ){
      assert( tokenType==TK_SPACE || tokenType==TK_ILLEGAL );
      if( db->u1.isInterrupted ){
        pParse->rc = SQLITE_INTERRUPT;
        break;
      }
      if( tokenType==TK_ILLEGAL ){
        sqlite3ErrorMsg(pParse, "unrecognized token: \"%.*s\"", n, zSql);

        break;
      }
      zSql += n;
    }else{
      pParse->sLastToken.z = zSql;
      pParse->sLastToken.n = n;
      sqlite3Parser(pEngine, tokenType, pParse->sLastToken, pParse);
      lastTokenParsed = tokenType;
      zSql += n;
      if( pParse->rc!=SQLITE_OK || db->mallocFailed ) break;
    }
  }
  assert( nErr==0 );
  pParse->zTail = zSql;
#ifdef YYTRACKMAXSTACKDEPTH
  sqlite3_mutex_enter(sqlite3MallocMutex());
  sqlite3StatusHighwater(SQLITE_STATUS_PARSER_STACK,
      sqlite3ParserStackPeak(pEngine)
  );
  sqlite3_mutex_leave(sqlite3MallocMutex());
#endif /* YYDEBUG */
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