compiler/stdc/memcmp.c

   1 /*
   2     Copyright © 1995-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     C99 function memcmp().
   6 */
   7
   8 #include <exec/types.h>
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13 #include <string.h>
  14
  15         int memcmp (
  16
  17 /*  SYNOPSIS */
  18         const void * s1,
  19         const void * s2,
  20         size_t       n)
  21
  22 /*  FUNCTION
  23         Calculate s1 - s2 for the n bytes after s1 and s2 and stop when
  24         the difference is not 0.
  25
  26     INPUTS
  27         s1, s2 - Begin of the memory areas to compare
  28         n - The number of bytes to compare
  29
  30     RESULT
  31         The difference of the memory areas. The difference is 0, if both
  32         are equal, < 0 if s1 < s2 and > 0 if s1 > s2. Note that it may be
  33         greater then 1 or less than -1.
  34
  35     NOTES
  36         This function is not part of a library and may thus be called
  37         any time.
  38
  39     EXAMPLE
  40
  41     BUGS
  42
  43     SEE ALSO
  44         strcmp(), strncmp(), strcasecmp(), strncasecmp()
  45
  46     INTERNALS
  47
  48 ******************************************************************************/
  49 {
  50     const UBYTE * str1,
  51                 * str2;
  52     int           diff = 0; /* In case we are comparing n == 0 */
  53
  54
  55     str1 = s1;
  56     str2 = s2;
  57
  58     while (n && !(diff = *str1 - *str2))
  59     {
  60         str1 ++;
  61         str2 ++;
  62         n --;
  63     }
  64
  65     /* Now return the difference. */
  66     return diff;
  67 } /* memcmp */
  68