benchmark.c

#include <stdio.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>

#define TESTS 10000000
#ifndef MISALIGNED
# define MISALIGNED 0
#endif

char testarray[512 + MISALIGNED];

extern int is_eof_block(const char[static 512]);

int main()
{
	size_t i, j;
	clock_t begin, end;

	fprintf(stderr, "testing %d times\n", TESTS);
	fprintf(stderr, "no byte set to 1... ");
	begin = clock();

	for (i = 0; i < TESTS; i++)
		if (!is_eof_block(testarray + MISALIGNED)) {
			fprintf(stderr, "\nWrong test result in iteration %zu!\n", i);
			return EXIT_FAILURE;
		}

	end = clock();
	fprintf(stderr, "%fs\n", (end - begin) / (double)CLOCKS_PER_SEC);

	fprintf(stderr, "with non-null byte... ");
	begin = clock();

	for (i = j = 0; i < TESTS; i++) {
		testarray[MISALIGNED + j] = '\0';
		j = (j + 47) & 511;
		testarray[MISALIGNED + j] = '1';

		if (is_eof_block(testarray + MISALIGNED)) {
			fprintf(stderr, "\nWrong test result in iteration %zu!\n", i);
			return EXIT_FAILURE;
		}		
	}

	end = clock();
	fprintf(stderr, "%fs\n", (end - begin) / (double)CLOCKS_PER_SEC);

	testarray[MISALIGNED + j] = '\0';
	testarray[MISALIGNED] = '1';

	fprintf(stderr, "first byte set to 1... ");
	begin = clock();

	for (i = 0; i < TESTS; i++)
		if (is_eof_block(testarray + MISALIGNED)) {
			fprintf(stderr, "\nWrong test result in iteration %zu!\n", i);
			return EXIT_FAILURE;
		}

	end = clock();
	fprintf(stderr, "%fs\n", (end - begin) / (double)CLOCKS_PER_SEC);


	return EXIT_SUCCESS;
}