1/*
2 * HOG support routines for PhysicsFS.
3 *
4 * This driver handles Descent I/II/III HOG archives.
5 *
6 * The Descent I/II format is very simple:
7 *
8 * The file always starts with the 3-byte signature "DHF" (Descent
9 * HOG file). After that the files of a HOG are just attached after
10 * another, divided by a 17 bytes header, which specifies the name
11 * and length (in bytes) of the forthcoming file! So you just read
12 * the header with its information of how big the following file is,
13 * and then skip exact that number of bytes to get to the next file
14 * in that HOG.
15 *
16 * char sig[3] = {'D', 'H', 'F'}; // "DHF"=Descent HOG File
17 *
18 * struct {
19 * char file_name[13]; // Filename, padded to 13 bytes with 0s
20 * int file_size; // filesize in bytes
21 * char data[file_size]; // The file data
22 * } FILE_STRUCT; // Repeated until the end of the file.
23 *
24 * (That info is from http://www.descent2.com/ddn/specs/hog/)
25 *
26 * Descent 3 moved to HOG2 format, which starts with the chars "HOG2",
27 * then 32-bits for the number of contained files, 32 bits for the offset
28 * to the first file's data, then 56 bytes of 0xFF (reserved?). Then for
29 * each file, there's 36 bytes for filename (null-terminated, rest of bytes
30 * are garbage), 32-bits unknown/reserved (always zero?), 32-bits of length
31 * of file data, 32-bits of time since Unix epoch. Then immediately following,
32 * for each file is their uncompressed content, you can find its offset
33 * by starting at the initial data offset and adding the filesize of each
34 * prior file.
35 *
36 * This information was found at:
37 * https://web.archive.org/web/20020213004051/http://descent-3.com/ddn/specs/hog/
38 *
39 *
40 * Please see the file LICENSE.txt in the source's root directory.
41 *
42 * This file written by Bradley Bell and Ryan C. Gordon.
43 */
44
45#define __PHYSICSFS_INTERNAL__
46#include "physfs_internal.h"
47
48#if PHYSFS_SUPPORTS_HOG
49
50static int readui32(PHYSFS_Io *io, PHYSFS_uint32 *val)
51{
52 PHYSFS_uint32 v;
53 BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, &v, sizeof (v)), 0);
54 *val = PHYSFS_swapULE32(v);
55 return 1;
56} /* readui32 */
57
58static int hog1LoadEntries(PHYSFS_Io *io, void *arc)
59{
60 const PHYSFS_uint64 iolen = io->length(io);
61 PHYSFS_uint32 pos = 3;
62
63 while (pos < iolen)
64 {
65 PHYSFS_uint32 size;
66 char name[13];
67
68 BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, name, 13), 0);
69 BAIL_IF_ERRPASS(!readui32(io, &size), 0);
70 name[12] = '\0'; /* just in case. */
71 pos += 13 + 4;
72
73 BAIL_IF_ERRPASS(!UNPK_addEntry(arc, name, 0, -1, -1, pos, size), 0);
74 pos += size;
75
76 /* skip over entry */
77 BAIL_IF_ERRPASS(!io->seek(io, pos), 0);
78 } /* while */
79
80 return 1;
81} /* hogLoadEntries */
82
83static int hog2LoadEntries(PHYSFS_Io *io, void *arc)
84{
85 PHYSFS_uint32 numfiles;
86 PHYSFS_uint32 pos;
87 PHYSFS_uint32 i;
88
89 BAIL_IF_ERRPASS(!readui32(io, &numfiles), 0);
90 BAIL_IF_ERRPASS(!readui32(io, &pos), 0);
91 BAIL_IF_ERRPASS(!io->seek(io, 68), 0); /* skip to end of header. */
92
93 for (i = 0; i < numfiles; i++) {
94 char name[37];
95 PHYSFS_uint32 reserved;
96 PHYSFS_uint32 size;
97 PHYSFS_uint32 mtime;
98 BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, name, 36), 0);
99 BAIL_IF_ERRPASS(!readui32(io, &reserved), 0);
100 BAIL_IF_ERRPASS(!readui32(io, &size), 0);
101 BAIL_IF_ERRPASS(!readui32(io, &mtime), 0);
102 name[36] = '\0'; /* just in case */
103 BAIL_IF_ERRPASS(!UNPK_addEntry(arc, name, 0, mtime, mtime, pos, size), 0);
104 pos += size;
105 }
106
107 return 1;
108} /* hog2LoadEntries */
109
110
111static void *HOG_openArchive(PHYSFS_Io *io, const char *name,
112 int forWriting, int *claimed)
113{
114 PHYSFS_uint8 buf[3];
115 void *unpkarc = NULL;
116 int hog1 = 0;
117
118 assert(io != NULL); /* shouldn't ever happen. */
119 BAIL_IF(forWriting, PHYSFS_ERR_READ_ONLY, NULL);
120 BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, buf, 3), NULL);
121
122 if (memcmp(buf, "DHF", 3) == 0)
123 hog1 = 1; /* original HOG (Descent 1 and 2) archive */
124 else
125 {
126 BAIL_IF(memcmp(buf, "HOG", 3) != 0, PHYSFS_ERR_UNSUPPORTED, NULL); /* Not HOG2 */
127 BAIL_IF_ERRPASS(!__PHYSFS_readAll(io, buf, 1), NULL);
128 BAIL_IF(buf[0] != '2', PHYSFS_ERR_UNSUPPORTED, NULL); /* Not HOG2 */
129 } /* else */
130
131 *claimed = 1;
132
133 unpkarc = UNPK_openArchive(io, 0, 1);
134 BAIL_IF_ERRPASS(!unpkarc, NULL);
135
136 if (!(hog1 ? hog1LoadEntries(io, unpkarc) : hog2LoadEntries(io, unpkarc)))
137 {
138 UNPK_abandonArchive(unpkarc);
139 return NULL;
140 } /* if */
141
142 return unpkarc;
143} /* HOG_openArchive */
144
145
146const PHYSFS_Archiver __PHYSFS_Archiver_HOG =
147{
148 CURRENT_PHYSFS_ARCHIVER_API_VERSION,
149 {
150 "HOG",
151 "Descent I/II/III HOG file format",
152 "Bradley Bell <btb@icculus.org>",
153 "https://icculus.org/physfs/",
154 0, /* supportsSymlinks */
155 },
156 HOG_openArchive,
157 UNPK_enumerate,
158 UNPK_openRead,
159 UNPK_openWrite,
160 UNPK_openAppend,
161 UNPK_remove,
162 UNPK_mkdir,
163 UNPK_stat,
164 UNPK_closeArchive
165};
166
167#endif /* defined PHYSFS_SUPPORTS_HOG */
168
169/* end of physfs_archiver_hog.c ... */
170
171