diff options
Diffstat (limited to 'sysdeps/generic/strncmp.c')
-rw-r--r-- | sysdeps/generic/strncmp.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/sysdeps/generic/strncmp.c b/sysdeps/generic/strncmp.c new file mode 100644 index 0000000000..623d9c5714 --- /dev/null +++ b/sysdeps/generic/strncmp.c @@ -0,0 +1,69 @@ +/* Copyright (C) 1991 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library 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 +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include <ansidecl.h> +#include <string.h> +#include <memcopy.h> + +/* Compare no more than N characters of S1 and S2, + returning less than, equal to or greater than zero + if S1 is lexiographically less than, equal to or + greater than S2. */ +int +DEFUN(strncmp, (s1, s2, n), + CONST char *s1 AND CONST char *s2 AND size_t n) +{ + unsigned reg_char c1 = '\0'; + unsigned reg_char c2 = '\0'; + + if (n >= 4) + { + size_t n4 = n >> 2; + do + { + c1 = (unsigned char) *s1++; + c2 = (unsigned char) *s2++; + if (c1 == '\0' || c1 != c2) + return c1 - c2; + c1 = (unsigned char) *s1++; + c2 = (unsigned char) *s2++; + if (c1 == '\0' || c1 != c2) + return c1 - c2; + c1 = (unsigned char) *s1++; + c2 = (unsigned char) *s2++; + if (c1 == '\0' || c1 != c2) + return c1 - c2; + c1 = (unsigned char) *s1++; + c2 = (unsigned char) *s2++; + if (c1 == '\0' || c1 != c2) + return c1 - c2; + } while (--n4 > 0); + n &= 3; + } + + while (n > 0) + { + c1 = (unsigned char) *s1++; + c2 = (unsigned char) *s2++; + if (c1 == '\0' || c1 != c2) + return c1 - c2; + n--; + } + + return c1 - c2; +} |