/* Case-insensitive string comparison function. Copyright (C) 1998-1999, 2005-2007 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include /* Specification. */ #include #include #include #define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch)) /* Compare 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 does not work with multibyte strings! */ int strcasecmp (const char *s1, const char *s2) { const unsigned char *p1 = (const unsigned char *) s1; const unsigned char *p2 = (const unsigned char *) s2; unsigned char c1, c2; if (p1 == p2) return 0; 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 (c1 > c2 ? 1 : c1 < c2 ? -1 : 0); }