/* Measure memmem functions. Copyright (C) 2013-2022 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 . */ #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