1/* Locale-specific memory comparison. 2 Copyright (C) 1999, 2002, 2003, 2004 Free Software Foundation, Inc. 3 4 This program is free software; you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 2, or (at your option) 7 any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program; if not, write to the Free Software Foundation, 16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 17 18/* Contributed by Paul Eggert <eggert@twinsun.com>. */ 19 20#ifdef HAVE_CONFIG_H 21# include <config.h> 22#endif 23 24#include "memcoll.h" 25 26#include <errno.h> 27#include <string.h> 28 29/* Compare S1 (with length S1LEN) and S2 (with length S2LEN) according 30 to the LC_COLLATE locale. S1 and S2 do not overlap, and are not 31 adjacent. Perhaps temporarily modify the bytes after S1 and S2, 32 but restore their original contents before returning. Set errno to an 33 error number if there is an error, and to zero otherwise. */ 34int 35memcoll (char *s1, size_t s1len, char *s2, size_t s2len) 36{ 37 int diff; 38 39#if HAVE_STRCOLL 40 41 char n1 = s1[s1len]; 42 char n2 = s2[s2len]; 43 44 s1[s1len++] = '\0'; 45 s2[s2len++] = '\0'; 46 47 while (! (errno = 0, (diff = strcoll (s1, s2)) || errno)) 48 { 49 /* strcoll found no difference, but perhaps it was fooled by NUL 50 characters in the data. Work around this problem by advancing 51 past the NUL chars. */ 52 size_t size1 = strlen (s1) + 1; 53 size_t size2 = strlen (s2) + 1; 54 s1 += size1; 55 s2 += size2; 56 s1len -= size1; 57 s2len -= size2; 58 59 if (s1len == 0) 60 { 61 if (s2len != 0) 62 diff = -1; 63 break; 64 } 65 else if (s2len == 0) 66 { 67 diff = 1; 68 break; 69 } 70 } 71 72 s1[s1len - 1] = n1; 73 s2[s2len - 1] = n2; 74 75#else 76 77 diff = memcmp (s1, s2, s1len < s2len ? s1len : s2len); 78 if (! diff) 79 diff = s1len < s2len ? -1 : s1len != s2len; 80 errno = 0; 81 82#endif 83 84 return diff; 85} 86