summaryrefslogtreecommitdiff
path: root/tests/test-memchr.c
blob: ab8d2c0da09a2d3070a646fd3679264ff8d42c68 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
/*
 * Copyright (C) 2008-2020 Free Software Foundation, Inc.
 * Written by Eric Blake and Bruno Haible
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

#include <string.h>

#include "signature.h"
SIGNATURE_CHECK (memchr, void *, (void const *, int, size_t));

#include <stdlib.h>

#include "zerosize-ptr.h"
#include "macros.h"

/* Calculating void * + int is not portable, so this wrapper converts
   to char * to make the tests easier to write.  */
#define MEMCHR (char *) memchr

int
main (void)
{
  size_t n = 0x100000;
  char *input = malloc (n);
  ASSERT (input);

  input[0] = 'a';
  input[1] = 'b';
  memset (input + 2, 'c', 1024);
  memset (input + 1026, 'd', n - 1028);
  input[n - 2] = 'e';
  input[n - 1] = 'a';

  /* Basic behavior tests.  */
  ASSERT (MEMCHR (input, 'a', n) == input);

  ASSERT (MEMCHR (input, 'a', 0) == NULL);
  ASSERT (MEMCHR (zerosize_ptr (), 'a', 0) == NULL);

  ASSERT (MEMCHR (input, 'b', n) == input + 1);
  ASSERT (MEMCHR (input, 'c', n) == input + 2);
  ASSERT (MEMCHR (input, 'd', n) == input + 1026);

  ASSERT (MEMCHR (input + 1, 'a', n - 1) == input + n - 1);
  ASSERT (MEMCHR (input + 1, 'e', n - 1) == input + n - 2);
  ASSERT (MEMCHR (input + 1, 0x789abc00 | 'e', n - 1) == input + n - 2);

  ASSERT (MEMCHR (input, 'f', n) == NULL);
  ASSERT (MEMCHR (input, '\0', n) == NULL);

  /* Check that a very long haystack is handled quickly if the byte is
     found near the beginning.  */
  {
    size_t repeat = 10000;
    for (; repeat > 0; repeat--)
      {
        ASSERT (MEMCHR (input, 'c', n) == input + 2);
      }
  }

  /* Alignment tests.  */
  {
    int i, j;
    for (i = 0; i < 32; i++)
      {
        for (j = 0; j < 256; j++)
          input[i + j] = j;
        for (j = 0; j < 256; j++)
          {
            ASSERT (MEMCHR (input + i, j, 256) == input + i + j);
          }
      }
  }

  /* Check that memchr() does not read past the first occurrence of the
     byte being searched.  See the Austin Group's clarification
     <https://www.opengroup.org/austin/docs/austin_454.txt>.
     Test both '\0' and something else, since some implementations
     special-case searching for NUL.
  */
  {
    char *page_boundary = (char *) zerosize_ptr ();
    /* Too small, and we miss cache line boundary tests; too large,
       and the test takes cubically longer to complete.  */
    int limit = 257;

    if (page_boundary != NULL)
      {
        for (n = 1; n <= limit; n++)
          {
            char *mem = page_boundary - n;
            memset (mem, 'X', n);
            ASSERT (MEMCHR (mem, 'U', n) == NULL);
            ASSERT (MEMCHR (mem, 0, n) == NULL);

            {
              size_t i;
              size_t k;

              for (i = 0; i < n; i++)
                {
                  mem[i] = 'U';
                  for (k = i + 1; k < n + limit; k++)
                    ASSERT (MEMCHR (mem, 'U', k) == mem + i);
                  mem[i] = 0;
                  for (k = i + 1; k < n + limit; k++)
                    ASSERT (MEMCHR (mem, 0, k) == mem + i);
                  mem[i] = 'X';
                }
            }
          }
      }
  }

  free (input);

  return 0;
}

Return to:

Send suggestions and report system problems to the System administrator.