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

   1 /* -*-c-*-
   2  *
   3  * $Id: crc32.c,v 1.2 2004/03/21 23:52:58 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 1.2  2004/03/21 23:52:58  mdw
  34  * Ooops, how did that slip by?  Fix return type of @ghcopy@.
  35  *
  36  * Revision 1.1  2001/04/19 18:26:32  mdw
  37  * Add CRC as another hash function.
  38  *
  39  */
  40
  41 /*----- Header files ------------------------------------------------------*/
  42
  43 #include <mLib/crc32.h>
  44 #include <mLib/sub.h>
  45
  46 #include "arena.h"
  47 #include "crc32.h"
  48 #include "ghash.h"
  49 #include "paranoia.h"
  50
  51 /*----- Main code ---------------------------------------------------------*/
  52
  53 typedef struct gctx {
  54   ghash h;
  55   uint32 c;
  56   octet buf[4];
  57 } gctx;
  58
  59 static const ghash_ops gops;
  60
  61 static ghash *ghinit(void)
  62 {
  63   gctx *g = S_CREATE(gctx);
  64   g->h.ops = &gops;
  65   g->c = 0;
  66   return (&g->h);
  67 }
  68
  69 static void ghhash(ghash *h, const void *p, size_t sz)
  70 {
  71   gctx *g = (gctx *)h;
  72   CRC32(g->c, g->c, p, sz);
  73 }
  74
  75 static octet *ghdone(ghash *h, void *buf)
  76 {
  77   gctx *g = (gctx *)h;
  78   if (!buf)
  79     buf = g->buf;
  80   STORE32(buf, g->c);
  81   return (buf);
  82 }
  83
  84 static void ghdestroy(ghash *h)
  85 {
  86   gctx *g = (gctx *)h;
  87   BURN(*g);
  88   S_DESTROY(g);
  89 }
  90
  91 static ghash *ghcopy(ghash *h)
  92 {
  93   gctx *g = (gctx *)h;
  94   gctx *gg = S_CREATE(gctx);
  95   memcpy(gg, g, sizeof(gctx));
  96   return (&gg->h);
  97 }
  98
  99 static const ghash_ops gops = { &gcrc32, ghhash, ghdone, ghdestroy, ghcopy };
 100 const gchash gcrc32 = { "crc32", 4, ghinit };
 101
 102 /*----- That's all, folks -------------------------------------------------*/