string/strcmp.c

   1 /* Copyright (C) 1991, 1996, 1997, 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <string.h>
  20 #include <memcopy.h>
  21
  22 #undef strcmp
  23
  24 /* Compare S1 and S2, returning less than, equal to or
  25    greater than zero if S1 is lexicographically less than,
  26    equal to or greater than S2.  */
  27 int
  28 strcmp (p1, p2)
  29      const char *p1;
  30      const char *p2;
  31 {
  32   register const unsigned char *s1 = (const unsigned char *) p1;
  33   register const unsigned char *s2 = (const unsigned char *) p2;
  34   unsigned reg_char c1, c2;
  35
  36   do
  37     {
  38       c1 = (unsigned char) *s1++;
  39       c2 = (unsigned char) *s2++;
  40       if (c1 == '\0')
  41         return c1 - c2;
  42     }
  43   while (c1 == c2);
  44
  45   return c1 - c2;
  46 }
  47 libc_hidden_builtin_def (strcmp)