1 /*
2 Copyright (C) 2001-2006, William Joseph.
3 All Rights Reserved.
4
5 This file is part of GtkRadiant.
6
7 GtkRadiant is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11
12 GtkRadiant is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GtkRadiant; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #if !defined( INCLUDED_PKZIP_H )
23 #define INCLUDED_PKZIP_H
24
25 #include "bytestreamutils.h"
26 #include "idatastream.h"
27 #include <algorithm>
28
29 class zip_magic
30 {
31 public:
32 bool operator==( const zip_magic& other ) const {
33 return m_value[0] == other.m_value[0]
34 && m_value[1] == other.m_value[1]
35 && m_value[2] == other.m_value[2]
36 && m_value[3] == other.m_value[3];
37 }
38 bool operator!=( const zip_magic& other ) const {
39 return !( *this == other );
40 }
41 char m_value[4];
42 };
43
istream_read_zip_magic(InputStream & istream,zip_magic & magic)44 inline void istream_read_zip_magic( InputStream& istream, zip_magic& magic ){
45 istream.read( reinterpret_cast<InputStream::byte_type*>( magic.m_value ), 4 );
46 }
47
48 struct zip_version
49 {
50 char version;
51 char ostype;
52 };
53
istream_read_zip_version(InputStream & istream,zip_version & version)54 inline void istream_read_zip_version( InputStream& istream, zip_version& version ){
55 version.version = istream_read_byte( istream );
56 version.ostype = istream_read_byte( istream );
57 }
58
59 struct zip_dostime
60 {
61 unsigned short time;
62 unsigned short date;
63 };
64
istream_read_zip_dostime(InputStream & istream,zip_dostime & dostime)65 inline void istream_read_zip_dostime( InputStream& istream, zip_dostime& dostime ){
66 dostime.time = istream_read_int16_le( istream );
67 dostime.date = istream_read_int16_le( istream );
68 }
69
70 const zip_magic zip_file_header_magic = { { 'P', 'K', 0x03, 0x04 } };
71
72 /* A. Local file header */
73 struct zip_file_header
74 {
75 zip_magic z_magic; /* local file header signature (0x04034b50) */
76 zip_version z_extract; /* version needed to extract */
77 unsigned short z_flags; /* general purpose bit flag */
78 unsigned short z_compr; /* compression method */
79 zip_dostime z_dostime; /* last mod file time (dos format) */
80 unsigned int z_crc32; /* crc-32 */
81 unsigned int z_csize; /* compressed size */
82 unsigned int z_usize; /* uncompressed size */
83 unsigned short z_namlen; /* filename length (null if stdin) */
84 unsigned short z_extras; /* extra field length */
85 /* followed by filename (of variable size) */
86 /* followed by extra field (of variable size) */
87 };
88
istream_read_zip_file_header(SeekableInputStream & istream,zip_file_header & file_header)89 inline void istream_read_zip_file_header( SeekableInputStream& istream, zip_file_header& file_header ){
90 istream_read_zip_magic( istream, file_header.z_magic );
91 istream_read_zip_version( istream, file_header.z_extract );
92 file_header.z_flags = istream_read_uint16_le( istream );
93 file_header.z_compr = istream_read_uint16_le( istream );
94 istream_read_zip_dostime( istream, file_header.z_dostime );
95 file_header.z_crc32 = istream_read_uint32_le( istream );
96 file_header.z_csize = istream_read_uint32_le( istream );
97 file_header.z_usize = istream_read_uint32_le( istream );
98 file_header.z_namlen = istream_read_uint16_le( istream );
99 file_header.z_extras = istream_read_uint16_le( istream );
100 istream.seek( file_header.z_namlen + file_header.z_extras, SeekableInputStream::cur );
101 };
102
103 /* B. data descriptor
104 * the data descriptor exists only if bit 3 of z_flags is set. It is byte aligned
105 * and immediately follows the last byte of compressed data. It is only used if
106 * the output media of the compressor was not seekable, eg. standard output.
107 */
108 const zip_magic zip_file_trailer_magic = { { 'P', 'K', 0x07, 0x08} };
109
110 struct zip_file_trailer
111 {
112 zip_magic z_magic;
113 unsigned int z_crc32; /* crc-32 */
114 unsigned int z_csize; /* compressed size */
115 unsigned int z_usize; /* uncompressed size */
116 };
117
istream_read_zip_file_trailer(InputStream & istream,zip_file_trailer & file_trailer)118 inline void istream_read_zip_file_trailer( InputStream& istream, zip_file_trailer& file_trailer ){
119 istream_read_zip_magic( istream, file_trailer.z_magic );
120 file_trailer.z_crc32 = istream_read_uint32_le( istream );
121 file_trailer.z_csize = istream_read_uint32_le( istream );
122 file_trailer.z_usize = istream_read_uint32_le( istream );
123 };
124
125
126 /* C. central directory structure:
127 [file header] . . . end of central dir record
128 */
129
130 /* directory file header
131 * - a single entry including filename, extras and comment may not exceed 64k.
132 */
133
134 const zip_magic zip_root_dirent_magic = { { 'P', 'K', 0x01, 0x02 } };
135
136 struct zip_root_dirent
137 {
138 zip_magic z_magic;
139 zip_version z_encoder; /* version made by */
140 zip_version z_extract; /* version need to extract */
141 unsigned short z_flags; /* general purpose bit flag */
142 unsigned short z_compr; /* compression method */
143 zip_dostime z_dostime; /* last mod file time&date (dos format) */
144 unsigned int z_crc32; /* crc-32 */
145 unsigned int z_csize; /* compressed size */
146 unsigned int z_usize; /* uncompressed size */
147 unsigned short z_namlen; /* filename length (null if stdin) */
148 unsigned short z_extras; /* extra field length */
149 unsigned short z_comment; /* file comment length */
150 unsigned short z_diskstart; /* disk number of start (if spanning zip over multiple disks) */
151 unsigned short z_filetype; /* internal file attributes, bit0 = ascii */
152 unsigned int z_filemode; /* extrnal file attributes, eg. msdos attrib byte */
153 unsigned int z_off; /* relative offset of local file header, seekval if singledisk */
154 /* followed by filename (of variable size) */
155 /* followed by extra field (of variable size) */
156 /* followed by file comment (of variable size) */
157 };
158
istream_read_zip_root_dirent(SeekableInputStream & istream,zip_root_dirent & root_dirent)159 inline void istream_read_zip_root_dirent( SeekableInputStream& istream, zip_root_dirent& root_dirent ){
160 istream_read_zip_magic( istream, root_dirent.z_magic );
161 istream_read_zip_version( istream, root_dirent.z_encoder );
162 istream_read_zip_version( istream, root_dirent.z_extract );
163 root_dirent.z_flags = istream_read_uint16_le( istream );
164 root_dirent.z_compr = istream_read_uint16_le( istream );
165 istream_read_zip_dostime( istream, root_dirent.z_dostime );
166 root_dirent.z_crc32 = istream_read_uint32_le( istream );
167 root_dirent.z_csize = istream_read_uint32_le( istream );
168 root_dirent.z_usize = istream_read_uint32_le( istream );
169 root_dirent.z_namlen = istream_read_uint16_le( istream );
170 root_dirent.z_extras = istream_read_uint16_le( istream );
171 root_dirent.z_comment = istream_read_uint16_le( istream );
172 root_dirent.z_diskstart = istream_read_uint16_le( istream );
173 root_dirent.z_filetype = istream_read_uint16_le( istream );
174 root_dirent.z_filemode = istream_read_uint32_le( istream );
175 root_dirent.z_off = istream_read_uint32_le( istream );
176 istream.seek( root_dirent.z_namlen + root_dirent.z_extras + root_dirent.z_comment, SeekableInputStream::cur );
177 }
178
179 /* end of central dir record */
180 const zip_magic zip_disk_trailer_magic = { { 'P', 'K', 0x05, 0x06 } };
181 const unsigned int disk_trailer_length = 22;
182 struct zip_disk_trailer
183 {
184 zip_magic z_magic;
185 unsigned short z_disk; /* number of this disk */
186 unsigned short z_finaldisk; /* number of the disk with the start of the central dir */
187 unsigned short z_entries; /* total number of entries in the central dir on this disk */
188 unsigned short z_finalentries; /* total number of entries in the central dir */
189 unsigned int z_rootsize; /* size of the central directory */
190 unsigned int z_rootseek; /* offset of start of central directory with respect to *
191 * the starting disk number */
192 unsigned short z_comment; /* zipfile comment length */
193 /* followed by zipfile comment (of variable size) */
194 };
195
istream_read_zip_disk_trailer(SeekableInputStream & istream,zip_disk_trailer & disk_trailer)196 inline void istream_read_zip_disk_trailer( SeekableInputStream& istream, zip_disk_trailer& disk_trailer ){
197 istream_read_zip_magic( istream, disk_trailer.z_magic );
198 disk_trailer.z_disk = istream_read_uint16_le( istream );
199 disk_trailer.z_finaldisk = istream_read_uint16_le( istream );
200 disk_trailer.z_entries = istream_read_uint16_le( istream );
201 disk_trailer.z_finalentries = istream_read_uint16_le( istream );
202 disk_trailer.z_rootsize = istream_read_uint32_le( istream );
203 disk_trailer.z_rootseek = istream_read_uint32_le( istream );
204 disk_trailer.z_comment = istream_read_uint16_le( istream );
205 istream.seek( disk_trailer.z_comment, SeekableInputStream::cur );
206 }
207
pkzip_find_disk_trailer(SeekableInputStream & istream)208 inline SeekableStream::position_type pkzip_find_disk_trailer( SeekableInputStream& istream ){
209 istream.seek( 0, SeekableInputStream::end );
210 SeekableStream::position_type start_position = istream.tell();
211 if ( start_position < disk_trailer_length ) {
212 return 0;
213 }
214 start_position -= disk_trailer_length;
215
216 zip_magic magic;
217 istream.seek( start_position );
218 istream_read_zip_magic( istream, magic );
219
220 if ( magic == zip_disk_trailer_magic ) {
221 return start_position;
222 }
223 else
224 {
225 const SeekableStream::position_type max_comment = 0x10000;
226 const SeekableStream::position_type bufshift = 6;
227 const SeekableStream::position_type bufsize = max_comment >> bufshift;
228 unsigned char buffer[bufsize];
229
230 SeekableStream::position_type search_end = ( max_comment < start_position ) ? start_position - max_comment : 0;
231 SeekableStream::position_type position = start_position;
232 while ( position != search_end )
233 {
234 StreamBase::size_type to_read = std::min( bufsize, position - search_end );
235 position -= to_read;
236
237 istream.seek( position );
238 StreamBase::size_type size = istream.read( buffer, to_read );
239
240 unsigned char* p = buffer + size;
241 while ( p != buffer )
242 {
243 --p;
244 magic.m_value[3] = magic.m_value[2];
245 magic.m_value[2] = magic.m_value[1];
246 magic.m_value[1] = magic.m_value[0];
247 magic.m_value[0] = *p;
248 if ( magic == zip_disk_trailer_magic ) {
249 return position + ( p - buffer );
250 }
251 }
252 }
253 return 0;
254 }
255 }
256
257 #endif
258