1  //
 2  // Copyright(C) 1993-1996 Id Software, Inc.
 3  // Copyright(C) 2005-2014 Simon Howard
 4  //
 5  // This program is free software; you can redistribute it and/or
 6  // modify it under the terms of the GNU General Public License
 7  // as published by the Free Software Foundation; either version 2
 8  // of the License, or (at your option) any later version.
 9  //
10  // This program is distributed in the hope that it will be useful,
11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  // GNU General Public License for more details.
14  //
15  // DESCRIPTION:
16  //       Generate a checksum of the WAD directory.
17  //
18  
19  #include <stdio.h>
20  #include <stdlib.h>
21  #include <string.h>
22  
23  #include "m_misc.h"
24  #include "sha1.h"
25  #include "w_checksum.h"
26  #include "w_wad.h"
27  
28  static wad_file_t **open_wadfiles = NULL;
29  static int num_open_wadfiles = 0;
30  
31  static int GetFileNumber(wad_file_t *handle)
32  {
33      int i;
34      int result;
35  
36      for (i=0; i<num_open_wadfiles; ++i)
37      {
38          if (open_wadfiles[i] == handle)
39          {
40              return i;
41          }
42      }
43  
44      // Not found in list.  This is a new file we haven't seen yet.
45      // Allocate another slot for this file.
46  
47      open_wadfiles = realloc(open_wadfiles,
48                              sizeof(wad_file_t *) * (num_open_wadfiles + 1));
49      open_wadfiles[num_open_wadfiles] = handle;
50  
51      result = num_open_wadfiles;
52      ++num_open_wadfiles;
53  
54      return result;
55  }
56  
57  static void ChecksumAddLump(sha1_context_t *sha1_context, lumpinfo_t *lump)
58  {
59      char buf[9];
60  
61      M_StringCopy(buf, lump->name, sizeof(buf));
62      SHA1_UpdateString(sha1_context, buf);
63      SHA1_UpdateInt32(sha1_context, GetFileNumber(lump->wad_file));
64      SHA1_UpdateInt32(sha1_context, lump->position);
65      SHA1_UpdateInt32(sha1_context, lump->size);
66  }
67  
68  void W_Checksum(sha1_digest_t digest)
69  {
70      sha1_context_t sha1_context;
71      unsigned int i;
72  
73      SHA1_Init(&sha1_context);
74  
75      num_open_wadfiles = 0;
76  
77      // Go through each entry in the WAD directory, adding information
78      // about each entry to the SHA1 hash.
79  
80      for (i=0; i<numlumps; ++i)
81      {
82          ChecksumAddLump(&sha1_context, &lumpinfo[i]);
83      }
84      
85      SHA1_Final(digest, &sha1_context);
86  }
87