tests/test-memchr.c

   1 /*
   2  * Copyright (C) 2008-2024 Free Software Foundation, Inc.
   3  * Written by Eric Blake and Bruno Haible
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program 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
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 #include <string.h>
  21
  22 #include "signature.h"
  23 SIGNATURE_CHECK (memchr, void *, (void const *, int, size_t));
  24
  25 #include <stdlib.h>
  26
  27 #include "zerosize-ptr.h"
  28 #include "macros.h"
  29
  30 /* Calculating void * + int is not portable, so this wrapper converts
  31    to char * to make the tests easier to write.  */
  32 #define MEMCHR (char *) memchr
  33
  34 int
  35 main (void)
  36 {
  37   size_t n = 0x100000;
  38   char *input = malloc (n);
  39   ASSERT (input);
  40
  41   input[0] = 'a';
  42   input[1] = 'b';
  43   memset (input + 2, 'c', 1024);
  44   memset (input + 1026, 'd', n - 1028);
  45   input[n - 2] = 'e';
  46   input[n - 1] = 'a';
  47
  48   /* Basic behavior tests.  */
  49   ASSERT (MEMCHR (input, 'a', n) == input);
  50
  51   ASSERT (MEMCHR (input, 'a', 0) == NULL);
  52
  53   {
  54     void *page_boundary = zerosize_ptr ();
  55     if (page_boundary)
  56       ASSERT (MEMCHR (page_boundary, 'a', 0) == NULL);
  57   }
  58
  59   ASSERT (MEMCHR (input, 'b', n) == input + 1);
  60   ASSERT (MEMCHR (input, 'c', n) == input + 2);
  61   ASSERT (MEMCHR (input, 'd', n) == input + 1026);
  62
  63   ASSERT (MEMCHR (input + 1, 'a', n - 1) == input + n - 1);
  64   ASSERT (MEMCHR (input + 1, 'e', n - 1) == input + n - 2);
  65   ASSERT (MEMCHR (input + 1, 0x789abc00 | 'e', n - 1) == input + n - 2);
  66
  67   ASSERT (MEMCHR (input, 'f', n) == NULL);
  68   ASSERT (MEMCHR (input, '\0', n) == NULL);
  69
  70   /* Check that a very long haystack is handled quickly if the byte is
  71      found near the beginning.  */
  72   {
  73     size_t repeat = 10000;
  74     for (; repeat > 0; repeat--)
  75       {
  76         ASSERT (MEMCHR (input, 'c', n) == input + 2);
  77       }
  78   }
  79
  80   /* Alignment tests.  */
  81   {
  82     int i, j;
  83     for (i = 0; i < 32; i++)
  84       {
  85         for (j = 0; j < 256; j++)
  86           input[i + j] = j;
  87         for (j = 0; j < 256; j++)
  88           {
  89             ASSERT (MEMCHR (input + i, j, 256) == input + i + j);
  90           }
  91       }
  92   }
  93
  94   /* Check that memchr() does not read past the first occurrence of the
  95      byte being searched.  See the Austin Group's clarification
  96      <https://www.opengroup.org/austin/docs/austin_454.txt>.
  97      Test both '\0' and something else, since some implementations
  98      special-case searching for NUL.
  99   */
 100   {
 101     char *page_boundary = (char *) zerosize_ptr ();
 102     /* Too small, and we miss cache line boundary tests; too large,
 103        and the test takes cubically longer to complete.  */
 104     int limit = 257;
 105
 106     if (page_boundary != NULL)
 107       {
 108         for (n = 1; n <= limit; n++)
 109           {
 110             char *mem = page_boundary - n;
 111             memset (mem, 'X', n);
 112             ASSERT (MEMCHR (mem, 'U', n) == NULL);
 113             ASSERT (MEMCHR (mem, 0, n) == NULL);
 114
 115             {
 116               size_t i;
 117               size_t k;
 118
 119               for (i = 0; i < n; i++)
 120                 {
 121                   mem[i] = 'U';
 122                   for (k = i + 1; k < n + limit; k++)
 123                     ASSERT (MEMCHR (mem, 'U', k) == mem + i);
 124                   mem[i] = 0;
 125                   for (k = i + 1; k < n + limit; k++)
 126                     ASSERT (MEMCHR (mem, 0, k) == mem + i);
 127                   mem[i] = 'X';
 128                 }
 129             }
 130           }
 131       }
 132   }
 133
 134   free (input);
 135
 136   return test_exit_status;
 137 }