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/*
* Copyright (C) 2008-2025 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"
/* Test the library, not the compiler+library. */
static void *
lib_memchr (void const *s, int c, size_t n)
{
return memchr (s, c, n);
}
static void *(*volatile volatile_memchr) (void const *, int, size_t)
= lib_memchr;
#undef memchr
#define memchr volatile_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);
{
void *page_boundary = zerosize_ptr ();
if (page_boundary)
ASSERT (memchr (page_boundary, '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);
/* Test zero-length operations on NULL pointers, allowed by
<https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3322.pdf>. */
ASSERT (memchr (NULL, '?', 0) == NULL);
return test_exit_status;
}
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