c_cpp/etc/md5_sha/endian.c

   1 /*
   2  * endian - Determine the byte order of a long on your machine.
   3  *
   4  * @(#) $Revision: 13.1 $
   5  * @(#) $Id: endian.c,v 13.1 2006/08/14 03:16:33 chongo Exp $
   6  * @(#) $Source: /usr/local/src/cmd/hash/RCS/endian.c,v $
   7  *
   8  * Big Endian:      Amdahl, 68k, Pyramid, Mips, Sparc, ...
   9  * Little Endian:   Vax, 32k, Spim (Dec Mips), i386, i486, ...
  10  *
  11  * This file was written by Landon Curt Noll.
  12  *
  13  * This code has been placed in the public domain.  Please do not
  14  * copyright this code.
  15  *
  16  * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH  REGARD  TO
  17  * THIS  SOFTWARE,  INCLUDING  ALL IMPLIED WARRANTIES OF MER-
  18  * CHANTABILITY AND FITNESS.  IN NO EVENT SHALL  LANDON  CURT
  19  * NOLL  BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
  20  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM  LOSS  OF
  21  * USE,  DATA  OR  PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  22  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR  IN
  23  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  24  *
  25  * chongo (was here) /\oo/\
  26  * http://www.isthe.com/chongo/index.html
  27  *
  28  * Share and enjoy! :-)
  29  *
  30  * See shsdrvr.c and md5drvr.c for version and modification history.
  31  */
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35
  36 /* byte order array */
  37 char byte[8] = { (char)0x12, (char)0x36, (char)0x48, (char)0x59,
  38                  (char)0x01, (char)0x23, (char)0x45, (char)0x67 };
  39
  40 /*ARGSUSED*/
  41 int
  42 main(int argc, char *argv[])
  43 {
  44     /* pointers into the byte order array */
  45     int *intp = (int *)byte;
  46
  47     /* usage */
  48     if (argc != 1) {
  49         fprintf(stderr, "usage: %s\n", argv[0]);
  50         exit(1);
  51     }
  52
  53     /* Print the standard <machine/endian.h> defines */
  54     printf("#undef BIG_ENDIAN\n");
  55     printf("#define BIG_ENDIAN\t4321\n");
  56     printf("#undef LITTLE_ENDIAN\n");
  57     printf("#define LITTLE_ENDIAN\t1234\n");
  58
  59     /* Determine byte order */
  60     printf("#undef BYTE_ORDER\n");
  61     if (intp[0] == 0x12364859) {
  62         /* Most Significant Byte first */
  63         printf("#define BYTE_ORDER\tBIG_ENDIAN\n");
  64     } else if (intp[0] == 0x59483612) {
  65         /* Least Significant Byte first */
  66         printf("#define BYTE_ORDER\tLITTLE_ENDIAN\n");
  67     } else {
  68         fprintf(stderr, "Unknown int Byte Order, set BYTE_ORDER in Makefile\n");
  69         exit(2);
  70     }
  71     exit(0);
  72 }