git.distorted.org.uk Git - u/mdw/catacomb/blob - crc32.c

   1 /* -*-c-*-
   2  *
   3  * $Id: crc32.c,v 1.3 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * Generic hash wrapper for CRC32
   6  *
   7  * (c) 2001 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Header files ------------------------------------------------------*/
  31
  32 #include <mLib/crc32.h>
  33 #include <mLib/sub.h>
  34
  35 #include "arena.h"
  36 #include "crc32.h"
  37 #include "ghash.h"
  38 #include "paranoia.h"
  39
  40 /*----- Main code ---------------------------------------------------------*/
  41
  42 typedef struct gctx {
  43   ghash h;
  44   uint32 c;
  45   octet buf[4];
  46 } gctx;
  47
  48 static const ghash_ops gops;
  49
  50 static ghash *ghinit(void)
  51 {
  52   gctx *g = S_CREATE(gctx);
  53   g->h.ops = &gops;
  54   g->c = 0;
  55   return (&g->h);
  56 }
  57
  58 static void ghhash(ghash *h, const void *p, size_t sz)
  59 {
  60   gctx *g = (gctx *)h;
  61   CRC32(g->c, g->c, p, sz);
  62 }
  63
  64 static octet *ghdone(ghash *h, void *buf)
  65 {
  66   gctx *g = (gctx *)h;
  67   if (!buf)
  68     buf = g->buf;
  69   STORE32(buf, g->c);
  70   return (buf);
  71 }
  72
  73 static void ghdestroy(ghash *h)
  74 {
  75   gctx *g = (gctx *)h;
  76   BURN(*g);
  77   S_DESTROY(g);
  78 }
  79
  80 static ghash *ghcopy(ghash *h)
  81 {
  82   gctx *g = (gctx *)h;
  83   gctx *gg = S_CREATE(gctx);
  84   memcpy(gg, g, sizeof(gctx));
  85   return (&gg->h);
  86 }
  87
  88 static const ghash_ops gops = { &gcrc32, ghhash, ghdone, ghdestroy, ghcopy };
  89 const gchash gcrc32 = { "crc32", 4, ghinit };
  90
  91 /*----- That's all, folks -------------------------------------------------*/