source: trunk/third/sendmail/libsm/b-strcmp.c @ 19204

/*
 * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

#include <sm/gen.h>
SM_RCSID("@(#)$Id: b-strcmp.c,v 1.1.1.1 2003-04-08 15:06:03 zacheiss Exp $")
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sm/string.h>

#define toseconds(x, y) (x.tv_sec - y.tv_sec)
#define SIZE    512
#define LOOPS   4000000L        /* initial number of loops */
#define MAXTIME 30L     /* "maximum" time to run single test */

void
fatal(str)
        char *str;
{
        perror(str);
        exit(1);
}

void
purpose()
{
        printf("This program benchmarks the performance differences between\n");
        printf("strcasecmp() and sm_strcasecmp().\n");
        printf("These tests may take several minutes to complete.\n");
}

int
main(argc, argv)
        int argc;
        char *argv[];
{
        long a;
        int k;
        bool doit = false;
        long loops;
        long j;
        long one, two;
        struct timeval t1, t2;
        char src1[SIZE], src2[SIZE];

# define OPTIONS        "d"
        while ((k = getopt(argc, argv, OPTIONS)) != -1)
        {
                switch ((char) k)
                {
                  case 'd':
                        doit = true;
                        break;

                  default:
                        break;
                }
        }

        if (!doit)
        {
                purpose();
                printf("If you want to run it, specify -d as option.\n");
                return 0;
        }

        /* Run-time comments to the user */
        purpose();
        printf("\n");
        for (k = 0; k < 3; k++)
        {
                switch (k)
                {
                  case 0:
                        (void) sm_strlcpy(src1, "1234567890", SIZE);
                        (void) sm_strlcpy(src2, "1234567890", SIZE);
                        break;
                  case 1:
                        (void) sm_strlcpy(src1, "1234567890", SIZE);
                        (void) sm_strlcpy(src2, "1234567891", SIZE);
                        break;
                  case 2:
                        (void) sm_strlcpy(src1, "1234567892", SIZE);
                        (void) sm_strlcpy(src2, "1234567891", SIZE);
                        break;
                }
                printf("Test %d: strcasecmp(%s, %s) versus sm_strcasecmp()\n",
                        k, src1, src2);
                loops = LOOPS;
                for (;;)
                {
                        j = 0;
                        if (gettimeofday(&t1, NULL) < 0)
                                fatal("gettimeofday");
                        for (a = 0; a < loops; a++)
                                j += strcasecmp(src1, src2);
                        if (gettimeofday(&t2, NULL) < 0)
                                fatal("gettimeofday");
                        one = toseconds(t2, t1);
                        printf("\tstrcasecmp() result: %ld seconds [%ld]\n",
                                one, j);

                        j = 0;
                        if (gettimeofday(&t1, NULL) < 0)
                                fatal("gettimeofday");
                        for (a = 0; a < loops; a++)
                                j += sm_strcasecmp(src1, src2);
                        if (gettimeofday(&t2, NULL) < 0)
                                fatal("gettimeofday");
                        two = toseconds(t2, t1);
                        printf("\tsm_strcasecmp() result: %ld seconds [%ld]\n",
                                two, j);

                        if (abs(one - two) > 2)
                                break;
                        loops += loops;
                        if (loops < 0L || one > MAXTIME)
                        {
                                printf("\t\t** results too close: no decision\n");
                                break;
                        }
                        else
                        {
                                printf("\t\t** results too close redoing test %ld times **\n",
                                        loops);
                        }
                }
        }

        printf("\n\n");
        printf("Interpreting the results:\n");
        printf("\tFor differences larger than 2 seconds, the lower value is\n");
        printf("\tbetter and that function should be used for performance\n");
        printf("\treasons.\n\n");
        printf("This program will re-run the tests when the difference is\n");
        printf("less than 2 seconds.\n");
        printf("The result will vary depending on the compiler optimization\n");        printf("level used. Compiling the sendmail libsm library with a\n");
        printf("better optimization level can change the results.\n");
        return 0;
}