benchtests/bench-memmem.c

   1 /* Measure memmem functions.
   2    Copyright (C) 2013-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #define TEST_MAIN
  20 #define TEST_NAME "memmem"
  21 #define BUF1PAGES 20
  22 #define ITERATIONS 500
  23 #include "bench-string.h"
  24
  25 typedef char *(*proto_t) (const void *, size_t, const void *, size_t);
  26 void *simple_memmem (const void *, size_t, const void *, size_t);
  27
  28 IMPL (simple_memmem, 0)
  29 IMPL (memmem, 1)
  30
  31 void *
  32 simple_memmem (const void *haystack, size_t haystack_len, const void *needle,
  33                size_t needle_len)
  34 {
  35   const char *begin;
  36   const char *const last_possible
  37     = (const char *) haystack + haystack_len - needle_len;
  38
  39   if (needle_len == 0)
  40     /* The first occurrence of the empty string is deemed to occur at
  41        the beginning of the string.  */
  42     return (void *) haystack;
  43
  44   /* Sanity check, otherwise the loop might search through the whole
  45      memory.  */
  46   if (__glibc_unlikely (haystack_len < needle_len))
  47     return NULL;
  48
  49   for (begin = (const char *) haystack; begin <= last_possible; ++begin)
  50     if (begin[0] == ((const char *) needle)[0] &&
  51         !memcmp ((const void *) &begin[1],
  52                  (const void *) ((const char *) needle + 1),
  53                  needle_len - 1))
  54       return (void *) begin;
  55
  56   return NULL;
  57 }
  58
  59 static void
  60 do_one_test (impl_t *impl, const void *haystack, size_t haystack_len,
  61              const void *needle, size_t needle_len, const void *expected)
  62 {
  63   size_t i, iters = INNER_LOOP_ITERS;
  64   timing_t start, stop, cur;
  65
  66   TIMING_NOW (start);
  67   for (i = 0; i < iters; ++i)
  68     {
  69       CALL (impl, haystack, haystack_len, needle, needle_len);
  70     }
  71   TIMING_NOW (stop);
  72
  73   TIMING_DIFF (cur, start, stop);
  74
  75   TIMING_PRINT_MEAN ((double) cur, (double) iters);
  76 }
  77
  78 static void
  79 do_test (const char *str, size_t len, size_t idx)
  80 {
  81   char tmpbuf[len];
  82
  83   memcpy (tmpbuf, buf1 + idx, len);
  84   memcpy (buf1 + idx, str, len);
  85
  86   printf ("String %s, offset %zd:", str, idx);
  87
  88   FOR_EACH_IMPL (impl, 0)
  89     do_one_test (impl, buf1, BUF1PAGES * page_size, str, len, buf1 + idx);
  90
  91   memcpy (buf1 + idx, tmpbuf, len);
  92
  93   putchar ('\n');
  94 }
  95
  96 static void
  97 do_random_tests (void)
  98 {
  99   for (size_t n = 0; n < ITERATIONS; ++n)
 100     {
 101       char tmpbuf[32];
 102
 103       size_t shift = random () % 11;
 104       size_t rel = random () % ((2 << (shift + 1)) * 64);
 105       size_t idx = MIN ((2 << shift) * 64 + rel, BUF1PAGES * page_size - 2);
 106       size_t len = random () % (sizeof (tmpbuf) - 1) + 1;
 107       len = MIN (len, BUF1PAGES * page_size - idx - 1);
 108       memcpy (tmpbuf, buf1 + idx, len);
 109       for (size_t i = random () % len / 2 + 1; i > 0; --i)
 110         {
 111           size_t off = random () % len;
 112           char ch = '0' + random () % 10;
 113
 114           buf1[idx + off] = ch;
 115         }
 116
 117       printf ("String %.*s, offset %zd:", (int) len, buf1 + idx, idx);
 118
 119       FOR_EACH_IMPL (impl, 0)
 120         do_one_test (impl, buf1, BUF1PAGES * page_size, buf1 + idx, len,
 121                      buf1 + idx);
 122
 123       putchar ('\n');
 124
 125       memcpy (buf1 + idx, tmpbuf, len);
 126     }
 127 }
 128
 129 static const char *const strs[] =
 130   {
 131     "00000", "00112233", "0123456789", "0000111100001111",
 132     "00000111110000022222", "012345678901234567890",
 133     "abc0", "aaaa0", "abcabc0"
 134   };
 135
 136
 137 int
 138 test_main (void)
 139 {
 140   size_t i;
 141
 142   test_init ();
 143
 144   printf ("%23s", "");
 145   FOR_EACH_IMPL (impl, 0)
 146     printf ("\t%s", impl->name);
 147   putchar ('\n');
 148
 149   for (i = 0; i < BUF1PAGES * page_size; ++i)
 150     buf1[i] = 60 + random () % 32;
 151
 152   for (i = 0; i < sizeof (strs) / sizeof (strs[0]); ++i)
 153     for (size_t j = 0; j < 120; j += 7)
 154       {
 155         size_t len = strlen (strs[i]);
 156
 157         do_test (strs[i], len, j);
 158       }
 159
 160   do_random_tests ();
 161   return ret;
 162 }
 163
 164 #include <support/test-driver.c>