benchtests/bench-strncmp.c

   1 /* Measure strncmp functions.
   2    Copyright (C) 2013-2017 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 #ifdef WIDE
  21 # define TEST_NAME "wcsncmp"
  22 #else
  23 # define TEST_NAME "strncmp"
  24 #endif /* !WIDE */
  25 #include "bench-string.h"
  26
  27 #ifdef WIDE
  28 # include <wchar.h>
  29
  30 # define L(str) L##str
  31 # define STRNCMP wcsncmp
  32 # define SIMPLE_STRNCMP simple_wcsncmp
  33 # define STUPID_STRNCMP stupid_wcsncmp
  34 # define CHAR wchar_t
  35 # define CHARBYTES 4
  36
  37 /* Wcsncmp uses signed semantics for comparison, not unsigned.
  38    Avoid using substraction since possible overflow.  */
  39 int
  40 simple_wcsncmp (const CHAR *s1, const CHAR *s2, size_t n)
  41 {
  42   wchar_t c1, c2;
  43
  44   while (n--)
  45     {
  46       c1 = *s1++;
  47       c2 = *s2++;
  48       if (c1 == L ('\0') || c1 != c2)
  49         return c1 > c2 ? 1 : (c1 < c2 ? -1 : 0);
  50     }
  51   return 0;
  52 }
  53
  54 int
  55 stupid_wcsncmp (const CHAR *s1, const CHAR *s2, size_t n)
  56 {
  57   wchar_t c1, c2;
  58   size_t ns1 = wcsnlen (s1, n) + 1, ns2 = wcsnlen (s2, n) + 1;
  59
  60   n = ns1 < n ? ns1 : n;
  61   n = ns2 < n ? ns2 : n;
  62
  63   while (n--)
  64     {
  65       c1 = *s1++;
  66       c2 = *s2++;
  67       if (c1 != c2)
  68         return c1 > c2 ? 1 : -1;
  69     }
  70   return 0;
  71 }
  72
  73 #else
  74 # define L(str) str
  75 # define STRNCMP strncmp
  76 # define SIMPLE_STRNCMP simple_strncmp
  77 # define STUPID_STRNCMP stupid_strncmp
  78 # define CHAR char
  79 # define CHARBYTES 1
  80
  81 /* Strncmp uses unsigned semantics for comparison.  */
  82 int
  83 simple_strncmp (const char *s1, const char *s2, size_t n)
  84 {
  85   int ret = 0;
  86
  87   while (n-- && (ret = *(unsigned char *) s1 - * (unsigned char *) s2++) == 0
  88          && *s1++);
  89   return ret;
  90 }
  91
  92 int
  93 stupid_strncmp (const char *s1, const char *s2, size_t n)
  94 {
  95   size_t ns1 = strnlen (s1, n) + 1, ns2 = strnlen (s2, n) + 1;
  96   int ret = 0;
  97
  98   n = ns1 < n ? ns1 : n;
  99   n = ns2 < n ? ns2 : n;
 100   while (n-- && (ret = *(unsigned char *) s1++ - *(unsigned char *) s2++) == 0);
 101   return ret;
 102 }
 103
 104 #endif /* !WIDE */
 105
 106 typedef int (*proto_t) (const CHAR *, const CHAR *, size_t);
 107
 108 IMPL (STUPID_STRNCMP, 0)
 109 IMPL (SIMPLE_STRNCMP, 0)
 110 IMPL (STRNCMP, 1)
 111
 112
 113 static void
 114 do_one_test (impl_t *impl, const CHAR *s1, const CHAR *s2, size_t n,
 115              int exp_result)
 116 {
 117   size_t i, iters = INNER_LOOP_ITERS;
 118   timing_t start, stop, cur;
 119
 120   TIMING_NOW (start);
 121   for (i = 0; i < iters; ++i)
 122     {
 123       CALL (impl, s1, s2, n);
 124     }
 125   TIMING_NOW (stop);
 126
 127   TIMING_DIFF (cur, start, stop);
 128
 129   TIMING_PRINT_MEAN ((double) cur, (double) iters);
 130 }
 131
 132 static void
 133 do_test_limit (size_t align1, size_t align2, size_t len, size_t n, int max_char,
 134          int exp_result)
 135 {
 136   size_t i, align_n;
 137   CHAR *s1, *s2;
 138
 139   if (n == 0)
 140     {
 141       s1 = (CHAR *) (buf1 + page_size);
 142       s2 = (CHAR *) (buf2 + page_size);
 143       printf ("Length %4zd/%4zd:", len, n);
 144
 145       FOR_EACH_IMPL (impl, 0)
 146         do_one_test (impl, s1, s2, n, 0);
 147
 148       putchar ('\n');
 149
 150       return;
 151     }
 152
 153   align1 &= 15;
 154   align2 &= 15;
 155   align_n = (page_size - n * CHARBYTES) & 15;
 156
 157   s1 = (CHAR *) (buf1 + page_size - n * CHARBYTES);
 158   s2 = (CHAR *) (buf2 + page_size - n * CHARBYTES);
 159
 160   if (align1 < align_n)
 161     s1 = (CHAR *) ((char *) s1 - (align_n - align1));
 162
 163   if (align2 < align_n)
 164     s2 = (CHAR *) ((char *) s2 - (align_n - align2));
 165
 166   for (i = 0; i < n; i++)
 167     s1[i] = s2[i] = 1 + 23 * i % max_char;
 168
 169   if (len < n)
 170     {
 171       s1[len] = 0;
 172       s2[len] = 0;
 173       if (exp_result < 0)
 174         s2[len] = 32;
 175       else if (exp_result > 0)
 176         s1[len] = 64;
 177     }
 178
 179   printf ("Length %4zd/%4zd, alignment %2zd/%2zd:", len, n, align1, align2);
 180
 181   FOR_EACH_IMPL (impl, 0)
 182     do_one_test (impl, s1, s2, n, exp_result);
 183
 184   putchar ('\n');
 185 }
 186
 187 static void
 188 do_test (size_t align1, size_t align2, size_t len, size_t n, int max_char,
 189          int exp_result)
 190 {
 191   size_t i;
 192   CHAR *s1, *s2;
 193
 194   if (n == 0)
 195     return;
 196
 197   align1 &= 63;
 198   if (align1 + (n + 1) * CHARBYTES >= page_size)
 199     return;
 200
 201   align2 &= 7;
 202   if (align2 + (n + 1) * CHARBYTES >= page_size)
 203     return;
 204
 205   s1 = (CHAR *) (buf1 + align1);
 206   s2 = (CHAR *) (buf2 + align2);
 207
 208   for (i = 0; i < n; i++)
 209     s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % max_char;
 210
 211   s1[n] = 24 + exp_result;
 212   s2[n] = 23;
 213   s1[len] = 0;
 214   s2[len] = 0;
 215   if (exp_result < 0)
 216     s2[len] = 32;
 217   else if (exp_result > 0)
 218     s1[len] = 64;
 219   if (len >= n)
 220     s2[n - 1] -= exp_result;
 221
 222   printf ("Length %4zd/%4zd, alignment %2zd/%2zd:", len, n, align1, align2);
 223
 224   FOR_EACH_IMPL (impl, 0)
 225     do_one_test (impl, s1, s2, n, exp_result);
 226
 227   putchar ('\n');
 228 }
 229
 230 int
 231 test_main (void)
 232 {
 233   size_t i;
 234
 235   test_init ();
 236
 237   printf ("%23s", "");
 238   FOR_EACH_IMPL (impl, 0)
 239     printf ("\t%s", impl->name);
 240   putchar ('\n');
 241
 242   for (i =0; i < 16; ++i)
 243     {
 244       do_test (0, 0, 8, i, 127, 0);
 245       do_test (0, 0, 8, i, 127, -1);
 246       do_test (0, 0, 8, i, 127, 1);
 247       do_test (i, i, 8, i, 127, 0);
 248       do_test (i, i, 8, i, 127, 1);
 249       do_test (i, i, 8, i, 127, -1);
 250       do_test (i, 2 * i, 8, i, 127, 0);
 251       do_test (2 * i, i, 8, i, 127, 1);
 252       do_test (i, 3 * i, 8, i, 127, -1);
 253       do_test (0, 0, 8, i, 255, 0);
 254       do_test (0, 0, 8, i, 255, -1);
 255       do_test (0, 0, 8, i, 255, 1);
 256       do_test (i, i, 8, i, 255, 0);
 257       do_test (i, i, 8, i, 255, 1);
 258       do_test (i, i, 8, i, 255, -1);
 259       do_test (i, 2 * i, 8, i, 255, 0);
 260       do_test (2 * i, i, 8, i, 255, 1);
 261       do_test (i, 3 * i, 8, i, 255, -1);
 262     }
 263
 264   for (i = 1; i < 8; ++i)
 265     {
 266       do_test (0, 0, 8 << i, 16 << i, 127, 0);
 267       do_test (0, 0, 8 << i, 16 << i, 127, 1);
 268       do_test (0, 0, 8 << i, 16 << i, 127, -1);
 269       do_test (0, 0, 8 << i, 16 << i, 255, 0);
 270       do_test (0, 0, 8 << i, 16 << i, 255, 1);
 271       do_test (0, 0, 8 << i, 16 << i, 255, -1);
 272       do_test (8 - i, 2 * i, 8 << i, 16 << i, 127, 0);
 273       do_test (8 - i, 2 * i, 8 << i, 16 << i, 127, 1);
 274       do_test (2 * i, i, 8 << i, 16 << i, 255, 0);
 275       do_test (2 * i, i, 8 << i, 16 << i, 255, 1);
 276     }
 277
 278   do_test_limit (0, 0, 0, 0, 127, 0);
 279   do_test_limit (4, 0, 21, 20, 127, 0);
 280   do_test_limit (0, 4, 21, 20, 127, 0);
 281   do_test_limit (8, 0, 25, 24, 127, 0);
 282   do_test_limit (0, 8, 25, 24, 127, 0);
 283
 284   for (i = 0; i < 8; ++i)
 285     {
 286       do_test_limit (0, 0, 17 - i, 16 - i, 127, 0);
 287       do_test_limit (0, 0, 17 - i, 16 - i, 255, 0);
 288       do_test_limit (0, 0, 15 - i, 16 - i, 127, 0);
 289       do_test_limit (0, 0, 15 - i, 16 - i, 127, 1);
 290       do_test_limit (0, 0, 15 - i, 16 - i, 127, -1);
 291       do_test_limit (0, 0, 15 - i, 16 - i, 255, 0);
 292       do_test_limit (0, 0, 15 - i, 16 - i, 255, 1);
 293       do_test_limit (0, 0, 15 - i, 16 - i, 255, -1);
 294     }
 295
 296   return ret;
 297 }
 298
 299 #include <support/test-driver.c>