112 lines
3.3 KiB
C
112 lines
3.3 KiB
C
/* Locale-specific memory comparison.
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Copyright (C) 1999, 2002-2004, 2006, 2009-2022 Free Software Foundation,
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Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Contributed by Paul Eggert <eggert@twinsun.com>. */
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#include <config.h>
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#include "memcoll.h"
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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/* Compare S1 (with size S1SIZE) and S2 (with length S2SIZE) according
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to the LC_COLLATE locale. S1 and S2 are both blocks of memory with
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nonzero sizes, and the last byte in each block must be a null byte.
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Set errno to an error number if there is an error, and to zero
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otherwise. */
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static int
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strcoll_loop (char const *s1, size_t s1size, char const *s2, size_t s2size)
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{
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int diff;
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while (! (errno = 0, (diff = strcoll (s1, s2)) || errno))
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{
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/* strcoll found no difference, but perhaps it was fooled by NUL
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characters in the data. Work around this problem by advancing
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past the NUL chars. */
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size_t size1 = strlen (s1) + 1;
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size_t size2 = strlen (s2) + 1;
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s1 += size1;
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s2 += size2;
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s1size -= size1;
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s2size -= size2;
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if (s1size == 0)
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return - (s2size != 0);
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if (s2size == 0)
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return 1;
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}
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return diff;
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}
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/* Compare S1 (with length S1LEN) and S2 (with length S2LEN) according
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to the LC_COLLATE locale. S1 and S2 do not overlap, and are not
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adjacent. Perhaps temporarily modify the bytes after S1 and S2,
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but restore their original contents before returning. Set errno to an
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error number if there is an error, and to zero otherwise. */
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int
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memcoll (char *s1, size_t s1len, char *s2, size_t s2len)
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{
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int diff;
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/* strcoll is slow on many platforms, so check for the common case
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where the arguments are bytewise equal. Otherwise, walk through
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the buffers using strcoll on each substring. */
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if (s1len == s2len && memcmp (s1, s2, s1len) == 0)
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{
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errno = 0;
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diff = 0;
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}
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else
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{
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char n1 = s1[s1len];
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char n2 = s2[s2len];
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s1[s1len] = '\0';
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s2[s2len] = '\0';
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diff = strcoll_loop (s1, s1len + 1, s2, s2len + 1);
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s1[s1len] = n1;
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s2[s2len] = n2;
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}
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return diff;
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}
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/* Compare S1 (a memory block of size S1SIZE, with a NUL as last byte)
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and S2 (a memory block of size S2SIZE, with a NUL as last byte)
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according to the LC_COLLATE locale. S1SIZE and S2SIZE must be > 0.
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Set errno to an error number if there is an error, and to zero
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otherwise. */
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int
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memcoll0 (char const *s1, size_t s1size, char const *s2, size_t s2size)
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{
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if (s1size == s2size && memcmp (s1, s2, s1size) == 0)
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{
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errno = 0;
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return 0;
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}
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else
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return strcoll_loop (s1, s1size, s2, s2size);
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}
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