mdw@git.distorted.org.uk Git - mLib/blob - hash/crc32.c

   1 /* -*-c-*-
   2  *
   3  * Calculating cyclic redundancy values (non-cryptographic!)
   4  *
   5  * (c) 1998 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  12  * mLib is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * mLib is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with mLib; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 /* --- ANSI headers --- */
  31
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35
  36 /* --- Local headers --- */
  37
  38 #include "bits.h"
  39 #include "crc32.h"
  40
  41 /*----- Functionc provided ------------------------------------------------*/
  42
  43 /* --- @crc32@ --- *
  44  *
  45  * Arguments:   @uint32 crc@ = carryover from previous call, or zero
  46  *              @const void *buf@ = pointer to buffer to check
  47  *              @size_t sz@ = size of the buffer
  48  *
  49  * Returns:     The CRC updated by the new buffer.
  50  *
  51  * Use:         A restartable CRC calculator.  This is just a function
  52  *              wrapper for the macro version.
  53  */
  54
  55 uint32 crc32(uint32 crc, const void *buf, size_t sz)
  56 {
  57   uint32 c;
  58   CRC32(c, crc, buf, sz);
  59   return (c);
  60 }
  61
  62 /*----- Test driver -------------------------------------------------------*/
  63
  64 #ifdef TEST_RIG
  65
  66 #include <stdio.h>
  67
  68 int main(void)
  69 {
  70   uint32 crc = 0;
  71   char buf[BUFSIZ];
  72   int r;
  73
  74   do {
  75     r = fread(buf, 1, sizeof(buf), stdin);
  76     if (r > 0)
  77       crc = crc32(crc, buf, r);
  78   } while (r == sizeof(buf));
  79
  80   printf("crc32(stdin) = %08lx\n", (unsigned long)crc);
  81   return (0);
  82 }
  83
  84 #endif
  85
  86 /*----- That's all, folks -------------------------------------------------*/