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Diffstat (limited to 'lib/mbscasecmp.c')
-rw-r--r-- | lib/mbscasecmp.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/lib/mbscasecmp.c b/lib/mbscasecmp.c new file mode 100644 index 0000000..3a20cb7 --- /dev/null +++ b/lib/mbscasecmp.c @@ -0,0 +1,102 @@ +/* Case-insensitive string comparison function. + Copyright (C) 1998-1999, 2005-2023 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2005, + based on earlier glibc code. + + This file 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 3 of the + License, or (at your option) any later version. + + This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */ + +#include <config.h> + +/* Specification. */ +#include <string.h> + +#include <ctype.h> +#include <limits.h> + +#include "mbuiterf.h" + +/* Compare the character strings S1 and S2, ignoring case, returning less than, + equal to or greater than zero if S1 is lexicographically less than, equal to + or greater than S2. + Note: This function may, in multibyte locales, return 0 for strings of + different lengths! */ +int +mbscasecmp (const char *s1, const char *s2) +{ + if (s1 == s2) + return 0; + + /* Be careful not to look at the entire extent of s1 or s2 until needed. + This is useful because when two strings differ, the difference is + most often already in the very few first characters. */ + if (MB_CUR_MAX > 1) + { + mbuif_state_t state1; + const char *iter1; + mbuif_init (state1); + iter1 = s1; + + mbuif_state_t state2; + const char *iter2; + mbuif_init (state2); + iter2 = s2; + + while (mbuif_avail (state1, iter1) && mbuif_avail (state2, iter2)) + { + mbchar_t cur1 = mbuif_next (state1, iter1); + mbchar_t cur2 = mbuif_next (state2, iter2); + int cmp = mb_casecmp (cur1, cur2); + + if (cmp != 0) + return cmp; + + iter1 += mb_len (cur1); + iter2 += mb_len (cur2); + } + if (mbuif_avail (state1, iter1)) + /* s2 terminated before s1. */ + return 1; + if (mbuif_avail (state2, iter2)) + /* s1 terminated before s2. */ + return -1; + return 0; + } + else + { + const unsigned char *p1 = (const unsigned char *) s1; + const unsigned char *p2 = (const unsigned char *) s2; + unsigned char c1, c2; + + do + { + c1 = tolower (*p1); + c2 = tolower (*p2); + + if (c1 == '\0') + break; + + ++p1; + ++p2; + } + while (c1 == c2); + + if (UCHAR_MAX <= INT_MAX) + return c1 - c2; + else + /* On machines where 'char' and 'int' are types of the same size, the + difference of two 'unsigned char' values - including the sign bit - + doesn't fit in an 'int'. */ + return _GL_CMP (c1, c2); + } +} |