libiberty/memcmp.c

   1 /* memcmp -- compare two memory regions.
   2    This function is in the public domain.  */
   3
   4 /*
   5
   6 @deftypefn Supplemental int memcmp (const void *@var{x}, const void *@var{y}, @
   7   size_t @var{count})
   8
   9 Compares the first @var{count} bytes of two areas of memory.  Returns
  10 zero if they are the same, a value less than zero if @var{x} is
  11 lexically less than @var{y}, or a value greater than zero if @var{x}
  12 is lexically greater than @var{y}.  Note that lexical order is determined
  13 as if comparing unsigned char arrays.
  14
  15 @end deftypefn
  16
  17 */
  18
  19 #include <ansidecl.h>
  20 #include <stddef.h>
  21
  22 int
  23 memcmp (const PTR str1, const PTR str2, size_t count)
  24 {
  25   register const unsigned char *s1 = (const unsigned char*)str1;
  26   register const unsigned char *s2 = (const unsigned char*)str2;
  27
  28   while (count-- > 0)
  29     {
  30       if (*s1++ != *s2++)
  31           return s1[-1] < s2[-1] ? -1 : 1;
  32     }
  33   return 0;
  34 }
  35