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

   1 /* -*-c-*-
   2  *
   3  * Generic hash wrapper for CRC32
   4  *
   5  * (c) 2001 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb 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  * Catacomb 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 Catacomb; 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 #include <mLib/crc32.h>
  31 #include <mLib/sub.h>
  32
  33 #include "arena.h"
  34 #include "crc32.h"
  35 #include "ghash.h"
  36 #include "paranoia.h"
  37
  38 /*----- Main code ---------------------------------------------------------*/
  39
  40 typedef struct gctx {
  41   ghash h;
  42   uint32 c;
  43   octet buf[4];
  44 } gctx;
  45
  46 static const ghash_ops gops;
  47
  48 static ghash *ghinit(void)
  49 {
  50   gctx *g = S_CREATE(gctx);
  51   g->h.ops = &gops;
  52   g->c = 0;
  53   return (&g->h);
  54 }
  55
  56 static void ghhash(ghash *h, const void *p, size_t sz)
  57 {
  58   gctx *g = (gctx *)h;
  59   CRC32(g->c, g->c, p, sz);
  60 }
  61
  62 static octet *ghdone(ghash *h, void *buf)
  63 {
  64   gctx *g = (gctx *)h;
  65   if (!buf)
  66     buf = g->buf;
  67   STORE32(buf, g->c);
  68   return (buf);
  69 }
  70
  71 static void ghdestroy(ghash *h)
  72 {
  73   gctx *g = (gctx *)h;
  74   BURN(*g);
  75   S_DESTROY(g);
  76 }
  77
  78 static ghash *ghcopy(ghash *h)
  79 {
  80   gctx *g = (gctx *)h;
  81   gctx *gg = S_CREATE(gctx);
  82   memcpy(gg, g, sizeof(gctx));
  83   return (&gg->h);
  84 }
  85
  86 static const ghash_ops gops = { &gcrc32, ghhash, ghdone, ghdestroy, ghcopy };
  87 const gchash gcrc32 = { "crc32", 4, ghinit };
  88
  89 /*----- That's all, folks -------------------------------------------------*/