usr/src/lib/libsum/common/sum-bsd.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1996-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                                                                      *
  19 ***********************************************************************/
  20 #pragma prototyped
  21
  22 /*
  23  * bsd
  24  */
  25
  26 #define bsd_description \
  27         "The BSD checksum."
  28 #define bsd_options     0
  29 #define bsd_match       "bsd|ucb"
  30 #define bsd_open        long_open
  31 #define bsd_init        long_init
  32 #define bsd_done        short_done
  33 #define bsd_print       long_print
  34 #define bsd_data        long_data
  35 #define bsd_scale       1024
  36
  37 static int
  38 bsd_block(register Sum_t* p, const void* s, size_t n)
  39 {
  40         register uint32_t       c = ((Integral_t*)p)->sum;
  41         register unsigned char* b = (unsigned char*)s;
  42         register unsigned char* e = b + n;
  43
  44         while (b < e)
  45                 c = ((c >> 1) + *b++ + ((c & 01) ? 0x8000 : 0)) & 0xffff;
  46         ((Integral_t*)p)->sum = c;
  47         return 0;
  48 }