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

   1 /* -*-c-*-
   2  *
   3  * $Id: crc32.c,v 1.1 2001/04/19 18:26:32 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 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: crc32.c,v $
  33  * Revision 1.1  2001/04/19 18:26:32  mdw
  34  * Add CRC as another hash function.
  35  *
  36  */
  37
  38 /*----- Header files ------------------------------------------------------*/
  39
  40 #include <mLib/crc32.h>
  41 #include <mLib/sub.h>
  42
  43 #include "arena.h"
  44 #include "crc32.h"
  45 #include "ghash.h"
  46 #include "paranoia.h"
  47
  48 /*----- Main code ---------------------------------------------------------*/
  49
  50 typedef struct gctx {
  51   ghash h;
  52   uint32 c;
  53   octet buf[4];
  54 } gctx;
  55
  56 static const ghash_ops gops;
  57
  58 static ghash *ghinit(void)
  59 {
  60   gctx *g = S_CREATE(gctx);
  61   g->h.ops = &gops;
  62   g->c = 0;
  63   return (&g->h);
  64 }
  65
  66 static void ghhash(ghash *h, const void *p, size_t sz)
  67 {
  68   gctx *g = (gctx *)h;
  69   CRC32(g->c, g->c, p, sz);
  70 }
  71
  72 static octet *ghdone(ghash *h, void *buf)
  73 {
  74   gctx *g = (gctx *)h;
  75   if (!buf)
  76     buf = g->buf;
  77   STORE32(buf, g->c);
  78   return (buf);
  79 }
  80
  81 static void ghdestroy(ghash *h)
  82 {
  83   gctx *g = (gctx *)h;
  84   BURN(*g);
  85   S_DESTROY(g);
  86 }
  87
  88 static void ghcopy(ghash *h)
  89 {
  90   gctx *g = (gctx *)h;
  91   gctx *gg = S_CREATE(gctx);
  92   memcpy(gg, g, sizeof(gctx));
  93   return (&gg->h);
  94 }
  95
  96 static const ghash_ops gops = { &gcrc32, ghhash, ghdone, ghdestroy, ghcopy };
  97 const gchash gcrc32 = { "crc32", 4, ghinit };
  98
  99 /*----- That's all, folks -------------------------------------------------*/