#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#include "papi.h"

#include "clockcore.h"

#define NUM_ITERS  1000000

static char *func_name[] = {

	"PAPI_get_real_cyc",

	"PAPI_get_real_usec",

	"PAPI_get_virt_cyc",

	"PAPI_get_virt_usec"

};

static int CLOCK_ERROR = 0;

static int

clock_res_check( int flag, int quiet )

{

	if ( CLOCK_ERROR ) {

		return -1;

	}

	long long *elapsed_cyc, total_cyc = 0, uniq_cyc = 0, diff_cyc = 0;

	int i;

	double min, max, average, std, tmp;

	elapsed_cyc = ( long long * ) calloc( NUM_ITERS, sizeof ( long long ) );

	/* Real */

	switch ( flag ) {

	case 0:

		for ( i = 0; i < NUM_ITERS; i++ )

			elapsed_cyc[i] = ( long long ) PAPI_get_real_cyc(  );

		break;

	case 1:

		for ( i = 0; i < NUM_ITERS; i++ )

			elapsed_cyc[i] = ( long long ) PAPI_get_real_usec(  );

		break;

	case 2:

		for ( i = 0; i < NUM_ITERS; i++ )

			elapsed_cyc[i] = ( long long ) PAPI_get_virt_cyc(  );

		break;

	case 3:

		for ( i = 0; i < NUM_ITERS; i++ )

			elapsed_cyc[i] = ( long long ) PAPI_get_virt_usec(  );

		break;

	default:

		return -1;

	}

	min = max = ( double ) ( elapsed_cyc[1] - elapsed_cyc[0] );

	for ( i = 1; i < NUM_ITERS; i++ ) {

		if ( elapsed_cyc[i] - elapsed_cyc[i - 1] < 0 ) {

			CLOCK_ERROR = 1;

			fprintf(stderr,"Error! Negative elapsed time\n");

			free( elapsed_cyc );

			return -1;

		}

		diff_cyc = elapsed_cyc[i] - elapsed_cyc[i - 1];

		if ( min > diff_cyc )

			min = ( double ) diff_cyc;

		if ( max < diff_cyc )

			max = ( double ) diff_cyc;

		if ( diff_cyc != 0 )

			uniq_cyc++;

		total_cyc += diff_cyc;

	}

	average = ( double ) total_cyc / ( NUM_ITERS - 1 );

	std = 0;

	for ( i = 1; i < NUM_ITERS; i++ ) {

		tmp = ( double ) ( elapsed_cyc[i] - elapsed_cyc[i - 1] );

		tmp = tmp - average;

		std += tmp * tmp;

	}

	if ( !quiet ) {

		std = sqrt( std / ( NUM_ITERS - 2 ) );

		printf( "%s: min %.3lf  max %.3lf \n", func_name[flag], min, max );

		printf( "                   average %.3lf std %.3lf\n", average, std );

		if ( uniq_cyc == NUM_ITERS - 1 ) {

			printf( "%s : %7.3f   <%7.3f\n", func_name[flag],

					( double ) total_cyc / ( double ) ( NUM_ITERS ),

					( double ) total_cyc / ( double ) uniq_cyc );

		} else if ( uniq_cyc ) {

			printf( "%s : %7.3f    %7.3f\n", func_name[flag],

					( double ) total_cyc / ( double ) ( NUM_ITERS ),

					( double ) total_cyc / ( double ) uniq_cyc );

		} else {

			printf( "%s : %7.3f   >%7.3f\n", func_name[flag],

					( double ) total_cyc / ( double ) ( NUM_ITERS ),

					( double ) total_cyc );

		}

	}

	free( elapsed_cyc );

	return PAPI_OK;

}

int

clockcore( int quiet )

{

	/* check PAPI_get_real_cyc */

	clock_res_check( 0, quiet );

	/* check PAPI_get_real_usec */

	clock_res_check( 1, quiet );

	/* check PAPI_get_virt_cyc */

	/* Virtual */

	if ( PAPI_get_virt_cyc(  ) != -1 ) {

		clock_res_check( 2, quiet );

	} else {

		return CLOCKCORE_VIRT_CYC_FAIL;

	}

	/* check PAPI_get_virt_usec */

	if ( PAPI_get_virt_usec(  ) != -1 ) {

		clock_res_check( 3, quiet );

	} else {

		return CLOCKCORE_VIRT_USEC_FAIL;

	}

	return PAPI_OK;

}