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/* Measure memmem functions.
Copyright (C) 2013-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#define TEST_MAIN
#define TEST_NAME "memmem"
#define BUF1PAGES 20
#define ITERATIONS 100
#include "bench-string.h"
typedef char *(*proto_t) (const void *, size_t, const void *, size_t);
void *
basic_memmem (const void *haystack, size_t hs_len, const void *needle,
size_t ne_len)
{
const char *hs = haystack;
const char *ne = needle;
if (ne_len == 0)
return (void *)hs;
int i;
int c = ne[0];
const char *end = hs + hs_len - ne_len;
for ( ; hs <= end; hs++)
{
if (hs[0] != c)
continue;
for (i = ne_len - 1; i != 0; i--)
if (hs[i] != ne[i])
break;
if (i == 0)
return (void *)hs;
}
return NULL;
}
#define RETURN_TYPE void *
#define AVAILABLE(h, h_l, j, n_l) ((j) <= (h_l) - (n_l))
#define FASTSEARCH(S,C,N) (void*) memchr ((void *)(S), (C), (N))
#include "../string/str-two-way.h"
void *
twoway_memmem (const void *haystack_start, size_t haystack_len,
const void *needle_start, size_t needle_len)
{
/* Abstract memory is considered to be an array of 'unsigned char' values,
not an array of 'char' values. See ISO C 99 section 6.2.6.1. */
const unsigned char *haystack = (const unsigned char *) haystack_start;
const unsigned char *needle = (const unsigned char *) needle_start;
if (needle_len == 0)
/* The first occurrence of the empty string is deemed to occur at
the beginning of the string. */
return (void *) haystack;
/* Sanity check, otherwise the loop might search through the whole
memory. */
if (__glibc_unlikely (haystack_len < needle_len))
return NULL;
/* Use optimizations in memchr when possible, to reduce the search
size of haystack using a linear algorithm with a smaller
coefficient. However, avoid memchr for long needles, since we
can often achieve sublinear performance. */
if (needle_len < LONG_NEEDLE_THRESHOLD)
{
haystack = memchr (haystack, *needle, haystack_len);
if (!haystack || __builtin_expect (needle_len == 1, 0))
return (void *) haystack;
haystack_len -= haystack - (const unsigned char *) haystack_start;
if (haystack_len < needle_len)
return NULL;
/* Check whether we have a match. This improves performance since we
avoid the initialization overhead of the two-way algorithm. */
if (memcmp (haystack, needle, needle_len) == 0)
return (void *) haystack;
return two_way_short_needle (haystack, haystack_len, needle, needle_len);
}
else
return two_way_long_needle (haystack, haystack_len, needle, needle_len);
}
IMPL (memmem, 1)
IMPL (twoway_memmem, 0)
IMPL (basic_memmem, 0)
static void
do_one_test (impl_t *impl, const void *haystack, size_t haystack_len,
const void *needle, size_t needle_len, const void *expected)
{
size_t i, iters = INNER_LOOP_ITERS_SMALL;
timing_t start, stop, cur;
TIMING_NOW (start);
for (i = 0; i < iters; ++i)
{
CALL (impl, haystack, haystack_len, needle, needle_len);
}
TIMING_NOW (stop);
TIMING_DIFF (cur, start, stop);
TIMING_PRINT_MEAN ((double) cur, (double) iters);
}
static void
do_test (const char *str, size_t len, size_t idx)
{
char tmpbuf[len];
memcpy (tmpbuf, buf1 + idx, len);
memcpy (buf1 + idx, str, len);
printf ("String %s, offset %zd:", str, idx);
FOR_EACH_IMPL (impl, 0)
do_one_test (impl, buf1, BUF1PAGES * page_size, str, len, buf1 + idx);
memcpy (buf1 + idx, tmpbuf, len);
putchar ('\n');
}
static void
do_random_tests (void)
{
for (size_t n = 0; n < ITERATIONS; ++n)
{
char tmpbuf[32];
size_t shift = random () % 11;
size_t rel = random () % ((2 << (shift + 1)) * 64);
size_t idx = MIN ((2 << shift) * 64 + rel, BUF1PAGES * page_size - 2);
size_t len = random () % (sizeof (tmpbuf) - 1) + 1;
len = MIN (len, BUF1PAGES * page_size - idx - 1);
memcpy (tmpbuf, buf1 + idx, len);
for (size_t i = random () % len / 2 + 1; i > 0; --i)
{
size_t off = random () % len;
char ch = '0' + random () % 10;
buf1[idx + off] = ch;
}
printf ("String %.*s, offset %zd:", (int) len, buf1 + idx, idx);
FOR_EACH_IMPL (impl, 0)
do_one_test (impl, buf1, BUF1PAGES * page_size, buf1 + idx, len,
buf1 + idx);
putchar ('\n');
memcpy (buf1 + idx, tmpbuf, len);
}
}
static const char *const strs[] =
{
"00000", "00112233", "0123456789", "0000111100001111",
"00000111110000022222", "012345678901234567890",
"abc0", "aaaa0", "abcabc0"
};
int
test_main (void)
{
size_t i;
test_init ();
printf ("%23s", "");
FOR_EACH_IMPL (impl, 0)
printf ("\t%s", impl->name);
putchar ('\n');
for (i = 0; i < BUF1PAGES * page_size; ++i)
buf1[i] = 60 + random () % 32;
for (i = 0; i < sizeof (strs) / sizeof (strs[0]); ++i)
for (size_t j = 0; j < 120; j += 7)
{
size_t len = strlen (strs[i]);
do_test (strs[i], len, j);
}
do_random_tests ();
return ret;
}
#include <support/test-driver.c>
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