[antlr-interest] reuse() methos in 3.4 C runtime

[Ruslan Zasukhin]

Hi Jim,

Below are copy-pastes of my class-wrapper around ANTLR3
Lexer/Parser/TreeParser.
So you can see if I made some stupid mistake...


>> On 6/24/11 7:49 PM, "Jim Idle" <jimi at temporal-wave.com> wrote:
>>
>> Because the documentation is not yet up to date, here is an example of
>> reusing the allocated memory in input streams and token streams:
>> 
>>     for (i=0; i<iterations; i++)
>>    {
>>         // Run the parser.
>>         psr->start(psr);
>> 
>>         // --------------------------------------
>>         // Now reset everything for the next run.
>>         // Order of calls is important.
>> 
>>         // Input stream can now be reused
>>         input->reuse(input, sourceCode, sourceLen, sourceName);
>> 
>>         // Reset the common token stream so that it will reuse its resources
>>         tstream->reset(tstream);
>> 
>>         // Reset the lexer (new function generated by antlr now)
>>         lxr->reset(lxr);
>> 
>>         // Reset the parser (new function generated by antlr now)
>>         psr->reset(psr);
>>     }


/**************************************************************************
void SqlParser_v3::ResuseParserObjects(
    const char*        inTextToParse,
    vuint32            inLength )
{
    // -------------------------------
    // TREE PARSER cannot be reused. Destroy it.
    //
    if( mpTreeParser )
    {
        mpTreeParser->free( mpTreeParser );
        mpTreeParser = NULL;
    }
    
    if( mpNodes )
    {
        mpNodes->free( mpNodes );
        mpNodes = NULL;
    }    


    // -------------------------------
    // Reuse other objects
    //
    mpInput->reuse(
        mpInput, 
        (pANTLR3_UINT8) inTextToParse,
        (ANTLR3_UINT32) inLength,
        (pANTLR3_UINT8) "VSQL" );

    mpTokenStream->reset( mpTokenStream );
    mpLexer         ->reset( mpLexer );
    mpParser     ->reset( mpParser );

    ResetOwnData( mpParser );
}



And few other related methods ...


/**************************************************************************
void SqlParser_v3::Parse_UTF8(
    I_SqlDatabaseEx*           inDatabase,
    const char*                inCommand,
    const char*                inCommandEnd )
{
    argused1(inDatabase);

//    COMMENT this line to force  REUSE() mode ...
//    DestroyParserObjects();

    if( mpInput ) 
        ResuseParserObjects( inCommand, (inCommandEnd - inCommand) );
    else
        CreateParserObjects( inCommand, (inCommandEnd - inCommand) );


    // -------------------------
    // Parse the input expression
    mAST = mpParser->sql( mpParser );


    // IF PARSER have generate some errors,
    // then we throw them as VSQL exception.
    if( mpParser->pParser->rec->state->errorCount )
    {    
        StToUTF16 cnv( ResultStringBuffer, pErrEnd, GetConverter_UTF8() );
        throw VSQL::xVSQLException( ERR_SQL_PARSER_ERROR, cnv.c_str() );
    }    
}


/**************************************************************************
void SqlParser_v3::CreateParserObjects(
    const char*        inTextToParse,
    vuint32            inLength )
{
    if( inTextToParse == NULL )
        return; // all objects will be still NULLs also.

    // ------------------------------
    // Create INPUT object:

    // NOTE: SQL strings do not have BOM - first few bytes, which define
endian of UTF16.
    //         So for UTF16, we must here self specify BE or LE.
    mpInput = antlr3StringStreamNew(
        (pANTLR3_UINT8) inTextToParse, mEncoding, (ANTLR3_UINT32) inLength,
(pANTLR3_UINT8) "VSQL" );

    mpInput->setUcaseLA( mpInput, ANTLR3_TRUE );


    // ------------------------------
    // Create LEXER v3 object:

    mpLexer = SqlParser_v3LexerNew( mpInput );
    mpTokenStream = antlr3CommonTokenStreamSourceNew( ANTLR3_SIZE_HINT,
TOKENSOURCE( mpLexer ) );


    // ------------------------------
    // Create PARSER v3 object:

    mpParser = SqlParser_v3ParserNew( mpTokenStream );  // is generated by
ANTLR3
    mpParser->mDoAllCommands = mDoAllCommandsInitial;

    ResetOwnData( mpParser );


/**************************************************************************
void SqlParser_v3::DestroyParserObjects( void )
{
    // REVERSE ORDER to construction:

    if( mpTreeParser )
    {
        mpTreeParser->free( mpTreeParser );
        mpTreeParser = NULL;
    }
    
    if( mpNodes )
    {
        mpNodes->free( mpNodes );
        mpNodes = NULL;
    }

    if( mpParser )
    {
        mpParser->mpStartPositions = NULL;
    
        mpParser->free( mpParser );
        mpParser = NULL;
    }
   
    if( mpTokenStream )
    {
        mpTokenStream->free( mpTokenStream );
        mpTokenStream = NULL;
    }    
    
    if( mpLexer )
    {
        mpLexer->free( mpLexer );
        mpLexer = NULL;
    }
    
    if( mpInput )
    {
        mpInput->close( mpInput );
        mpInput = NULL;
    }
}






-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]