| 1 | /* Case-insensitive string comparison function.
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| 2 | Copyright (C) 1998-1999, 2005-2006 Free Software Foundation, Inc.
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| 3 | Written by Bruno Haible <bruno@clisp.org>, 2005,
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| 4 | based on earlier glibc code.
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| 5 |
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| 6 | This program is free software; you can redistribute it and/or modify
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| 7 | it under the terms of the GNU General Public License as published by
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| 8 | the Free Software Foundation; either version 2, or (at your option)
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| 9 | any later version.
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| 10 |
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| 11 | This program is distributed in the hope that it will be useful,
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 14 | GNU General Public License for more details.
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| 15 |
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| 16 | You should have received a copy of the GNU General Public License
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| 17 | along with this program; if not, write to the Free Software Foundation,
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| 18 | Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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| 19 |
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| 20 | #include <config.h>
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| 21 |
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| 22 | /* Specification. */
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| 23 | #include "strcase.h"
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| 24 |
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| 25 | #include <ctype.h>
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| 26 | #include <limits.h>
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| 27 |
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| 28 | #if HAVE_MBRTOWC
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| 29 | # include "mbuiter.h"
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| 30 | #endif
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| 31 |
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| 32 | #define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch))
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| 33 |
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| 34 | /* Compare strings S1 and S2, ignoring case, returning less than, equal to or
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| 35 | greater than zero if S1 is lexicographically less than, equal to or greater
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| 36 | than S2.
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| 37 | Note: This function may, in multibyte locales, return 0 for strings of
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| 38 | different lengths! */
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| 39 | int
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| 40 | strcasecmp (const char *s1, const char *s2)
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| 41 | {
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| 42 | if (s1 == s2)
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| 43 | return 0;
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| 44 |
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| 45 | /* Be careful not to look at the entire extent of s1 or s2 until needed.
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| 46 | This is useful because when two strings differ, the difference is
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| 47 | most often already in the very few first characters. */
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| 48 | #if HAVE_MBRTOWC
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| 49 | if (MB_CUR_MAX > 1)
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| 50 | {
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| 51 | mbui_iterator_t iter1;
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| 52 | mbui_iterator_t iter2;
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| 53 |
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| 54 | mbui_init (iter1, s1);
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| 55 | mbui_init (iter2, s2);
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| 56 |
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| 57 | while (mbui_avail (iter1) && mbui_avail (iter2))
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| 58 | {
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| 59 | int cmp = mb_casecmp (mbui_cur (iter1), mbui_cur (iter2));
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| 60 |
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| 61 | if (cmp != 0)
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| 62 | return cmp;
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| 63 |
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| 64 | mbui_advance (iter1);
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| 65 | mbui_advance (iter2);
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| 66 | }
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| 67 | if (mbui_avail (iter1))
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| 68 | /* s2 terminated before s1. */
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| 69 | return 1;
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| 70 | if (mbui_avail (iter2))
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| 71 | /* s1 terminated before s2. */
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| 72 | return -1;
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| 73 | return 0;
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| 74 | }
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| 75 | else
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| 76 | #endif
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| 77 | {
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| 78 | const unsigned char *p1 = (const unsigned char *) s1;
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| 79 | const unsigned char *p2 = (const unsigned char *) s2;
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| 80 | unsigned char c1, c2;
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| 81 |
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| 82 | do
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| 83 | {
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| 84 | c1 = TOLOWER (*p1);
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| 85 | c2 = TOLOWER (*p2);
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| 86 |
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| 87 | if (c1 == '\0')
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| 88 | break;
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| 89 |
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| 90 | ++p1;
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| 91 | ++p2;
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| 92 | }
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| 93 | while (c1 == c2);
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| 94 |
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| 95 | if (UCHAR_MAX <= INT_MAX)
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| 96 | return c1 - c2;
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| 97 | else
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| 98 | /* On machines where 'char' and 'int' are types of the same size, the
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| 99 | difference of two 'unsigned char' values - including the sign bit -
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| 100 | doesn't fit in an 'int'. */
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| 101 | return (c1 > c2 ? 1 : c1 < c2 ? -1 : 0);
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| 102 | }
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| 103 | }
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