Loop Performance Sample Code

void TimingTest( long lTestType )
{
	char		theExpression[ 128 ];
	char		szTestType[ 32 ];

	bool		bResult;

	long		lInnerLoop;
	long		lOuterLoop;
	
	long		lStartTime;
	long		lEndTime;
	long		lResolveIndex;
	
	double		dWazoo = 0.0;
	double		dFester = 0.0;
	double		dResult = 0.0;
	long		lTests = 5000000;
	double		dCompiledTime;
	double		dParserTime;

	LZObjectHandle	hContextID = 0;
	LZObjectHandle	hExpression = 0;
	
	lzClearContext();
	lzCreatePrivateContext( "TimingTest" );
	hContextID = lzSetContext( "TimingTest", false );
	
	lzEvalExpStrToNum( "global number fester; global number wazoo; fester=wazoo=0" );
	
	if ( lzGetLastErrorID() )
		cout << lzGetLastErrorText() << '\n';
	
	switch ( lTestType )
	{
	case 70:	// "Internal" Loop
		strcpy( szTestType, "Internal Loop" );
		
		strcpy( theExpression, "tests=5000000; until (tests-- < 0) do fester++; wazoo += fester^2 + 5*fester - 10; next; return wazoo" );
		//strcpy( theExpression, "tests = -5000000; until (tests++ > 0) do wazoo += sqrt(tests); next; return wazoo" );
		//strcpy( theExpression, "tests = 5000000; until (tests-- < 0) do wazoo += sqrt(tests); next; return wazoo" );
		
		lzEvalExpStrToNum( "global number fester; global number wazoo; fester=wazoo=0" );
		hExpression = lzParseExp( theExpression );
				
		if ( lzGetLastErrorID() )
			cout << lzGetLastErrorText() << '\n';

		cout.flush();
		lStartTime = clock();
		dWazoo = lzEvalExpHndlToNum( hExpression );
		break;

	case 80:	// "External" loop
		strcpy( szTestType, "External Loop" );
		
		// Expressions from Gary Beene's review of parsers...
		//  http://www.garybeene.com/reviews/rev-parsers.htm

		//strcpy( theExpression, "fester*2+wazoo*2" );
		//strcpy( theExpression, "sin(fester)+sin(wazoo)" );
		//strcpy( theExpression, "fester^2+wazoo^2" );
		strcpy( theExpression, "abs(sin(sqrt(fester^2+wazoo^2))*255)" );
		//strcpy( theExpression, "abs(sin(sqrt(fester*fester+wazoo*wazoo))*255)" );

		lzLinkNumVar( 'G', "wazoo", &dWazoo );
		lzLinkNumVar( 'G', "fester", &dFester );

		hExpression = lzParseExp( theExpression );
				
		if ( lzGetLastErrorID() )
			cout << lzGetLastErrorText() << '\n';

		lInnerLoop = 2000;
		lOuterLoop = 2000;

		lTests = lInnerLoop * lOuterLoop;

		cout.flush();
		lStartTime = clock();

		for ( dFester = 1; dFester <= lOuterLoop; dFester++ )
			for ( dWazoo = 1; dWazoo <= lInnerLoop; dWazoo++ )
				dResult = lzEvalExpHndlToNum( hExpression );

		break;

	default:
		strcpy( szTestType, "No Test Selected" );
		cout.flush();
		lStartTime = clock();
		break;
	}

	lEndTime = clock();
	
	cout << dResult << '\n' << '\n';

	dParserTime = lEndTime - lStartTime;
	
	cout << szTestType << '\n';
	cout << "Elapsed time (ticks): " << (lEndTime - lStartTime) << '\n' << '\n';
	cout <<	"MIPS: " << (lTests / (dParserTime / MIPS_CONSTANT)) << '\n';
	cout.flush();
	
	lzClearContext();
	lzDestroyPrivateContext( "TimingTest" );
	
	lzReset();
}