vmap/plugins/archivezip/pkzip.h

258 lines
9.5 KiB
C++

/*
Copyright (C) 2001-2006, William Joseph.
All Rights Reserved.
This file is part of GtkRadiant.
GtkRadiant is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
GtkRadiant is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#if !defined( INCLUDED_PKZIP_H )
#define INCLUDED_PKZIP_H
#include "bytestreamutils.h"
#include "idatastream.h"
#include <algorithm>
class zip_magic {
public:
bool operator==(const zip_magic &other) const
{
return m_value[0] == other.m_value[0]
&& m_value[1] == other.m_value[1]
&& m_value[2] == other.m_value[2]
&& m_value[3] == other.m_value[3];
}
bool operator!=(const zip_magic &other) const
{
return !(*this == other);
}
char m_value[4];
};
inline void istream_read_zip_magic(InputStream &istream, zip_magic &magic)
{
istream.read(reinterpret_cast<InputStream::byte_type *>( magic.m_value ), 4);
}
struct zip_version {
char version;
char ostype;
};
inline void istream_read_zip_version(InputStream &istream, zip_version &version)
{
version.version = istream_read_byte(istream);
version.ostype = istream_read_byte(istream);
}
struct zip_dostime {
unsigned short time;
unsigned short date;
};
inline void istream_read_zip_dostime(InputStream &istream, zip_dostime &dostime)
{
dostime.time = istream_read_int16_le(istream);
dostime.date = istream_read_int16_le(istream);
}
const zip_magic zip_file_header_magic = {{'P', 'K', 0x03, 0x04}};
/* A. Local file header */
struct zip_file_header {
zip_magic z_magic; /* local file header signature (0x04034b50) */
zip_version z_extract; /* version needed to extract */
unsigned short z_flags; /* general purpose bit flag */
unsigned short z_compr; /* compression method */
zip_dostime z_dostime; /* last mod file time (dos format) */
unsigned int z_crc32; /* crc-32 */
unsigned int z_csize; /* compressed size */
unsigned int z_usize; /* uncompressed size */
unsigned short z_namlen; /* filename length (null if stdin) */
unsigned short z_extras; /* extra field length */
/* followed by filename (of variable size) */
/* followed by extra field (of variable size) */
};
inline void istream_read_zip_file_header(SeekableInputStream &istream, zip_file_header &file_header)
{
istream_read_zip_magic(istream, file_header.z_magic);
istream_read_zip_version(istream, file_header.z_extract);
file_header.z_flags = istream_read_uint16_le(istream);
file_header.z_compr = istream_read_uint16_le(istream);
istream_read_zip_dostime(istream, file_header.z_dostime);
file_header.z_crc32 = istream_read_uint32_le(istream);
file_header.z_csize = istream_read_uint32_le(istream);
file_header.z_usize = istream_read_uint32_le(istream);
file_header.z_namlen = istream_read_uint16_le(istream);
file_header.z_extras = istream_read_uint16_le(istream);
istream.seek(file_header.z_namlen + file_header.z_extras, SeekableInputStream::cur);
}
/* B. data descriptor
* the data descriptor exists only if bit 3 of z_flags is set. It is byte aligned
* and immediately follows the last byte of compressed data. It is only used if
* the output media of the compressor was not seekable, eg. standard output.
*/
const zip_magic zip_file_trailer_magic = {{'P', 'K', 0x07, 0x08}};
struct zip_file_trailer {
zip_magic z_magic;
unsigned int z_crc32; /* crc-32 */
unsigned int z_csize; /* compressed size */
unsigned int z_usize; /* uncompressed size */
};
inline void istream_read_zip_file_trailer(InputStream &istream, zip_file_trailer &file_trailer)
{
istream_read_zip_magic(istream, file_trailer.z_magic);
file_trailer.z_crc32 = istream_read_uint32_le(istream);
file_trailer.z_csize = istream_read_uint32_le(istream);
file_trailer.z_usize = istream_read_uint32_le(istream);
}
/* C. central directory structure:
[file header] . . . end of central dir record
*/
/* directory file header
* - a single entry including filename, extras and comment may not exceed 64k.
*/
const zip_magic zip_root_dirent_magic = {{'P', 'K', 0x01, 0x02}};
struct zip_root_dirent {
zip_magic z_magic;
zip_version z_encoder; /* version made by */
zip_version z_extract; /* version need to extract */
unsigned short z_flags; /* general purpose bit flag */
unsigned short z_compr; /* compression method */
zip_dostime z_dostime; /* last mod file time&date (dos format) */
unsigned int z_crc32; /* crc-32 */
unsigned int z_csize; /* compressed size */
unsigned int z_usize; /* uncompressed size */
unsigned short z_namlen; /* filename length (null if stdin) */
unsigned short z_extras; /* extra field length */
unsigned short z_comment; /* file comment length */
unsigned short z_diskstart; /* disk number of start (if spanning zip over multiple disks) */
unsigned short z_filetype; /* internal file attributes, bit0 = ascii */
unsigned int z_filemode; /* extrnal file attributes, eg. msdos attrib byte */
unsigned int z_off; /* relative offset of local file header, seekval if singledisk */
/* followed by filename (of variable size) */
/* followed by extra field (of variable size) */
/* followed by file comment (of variable size) */
};
inline void istream_read_zip_root_dirent(SeekableInputStream &istream, zip_root_dirent &root_dirent)
{
istream_read_zip_magic(istream, root_dirent.z_magic);
istream_read_zip_version(istream, root_dirent.z_encoder);
istream_read_zip_version(istream, root_dirent.z_extract);
root_dirent.z_flags = istream_read_uint16_le(istream);
root_dirent.z_compr = istream_read_uint16_le(istream);
istream_read_zip_dostime(istream, root_dirent.z_dostime);
root_dirent.z_crc32 = istream_read_uint32_le(istream);
root_dirent.z_csize = istream_read_uint32_le(istream);
root_dirent.z_usize = istream_read_uint32_le(istream);
root_dirent.z_namlen = istream_read_uint16_le(istream);
root_dirent.z_extras = istream_read_uint16_le(istream);
root_dirent.z_comment = istream_read_uint16_le(istream);
root_dirent.z_diskstart = istream_read_uint16_le(istream);
root_dirent.z_filetype = istream_read_uint16_le(istream);
root_dirent.z_filemode = istream_read_uint32_le(istream);
root_dirent.z_off = istream_read_uint32_le(istream);
istream.seek(root_dirent.z_namlen + root_dirent.z_extras + root_dirent.z_comment, SeekableInputStream::cur);
}
/* end of central dir record */
const zip_magic zip_disk_trailer_magic = {{'P', 'K', 0x05, 0x06}};
const unsigned int disk_trailer_length = 22;
struct zip_disk_trailer {
zip_magic z_magic;
unsigned short z_disk; /* number of this disk */
unsigned short z_finaldisk; /* number of the disk with the start of the central dir */
unsigned short z_entries; /* total number of entries in the central dir on this disk */
unsigned short z_finalentries; /* total number of entries in the central dir */
unsigned int z_rootsize; /* size of the central directory */
unsigned int z_rootseek; /* offset of start of central directory with respect to *
* the starting disk number */
unsigned short z_comment; /* zipfile comment length */
/* followed by zipfile comment (of variable size) */
};
inline void istream_read_zip_disk_trailer(SeekableInputStream &istream, zip_disk_trailer &disk_trailer)
{
istream_read_zip_magic(istream, disk_trailer.z_magic);
disk_trailer.z_disk = istream_read_uint16_le(istream);
disk_trailer.z_finaldisk = istream_read_uint16_le(istream);
disk_trailer.z_entries = istream_read_uint16_le(istream);
disk_trailer.z_finalentries = istream_read_uint16_le(istream);
disk_trailer.z_rootsize = istream_read_uint32_le(istream);
disk_trailer.z_rootseek = istream_read_uint32_le(istream);
disk_trailer.z_comment = istream_read_uint16_le(istream);
istream.seek(disk_trailer.z_comment, SeekableInputStream::cur);
}
inline SeekableStream::position_type pkzip_find_disk_trailer(SeekableInputStream &istream)
{
istream.seek(0, SeekableInputStream::end);
SeekableStream::position_type start_position = istream.tell();
if (start_position < disk_trailer_length) {
return 0;
}
start_position -= disk_trailer_length;
zip_magic magic;
istream.seek(start_position);
istream_read_zip_magic(istream, magic);
if (magic == zip_disk_trailer_magic) {
return start_position;
} else {
const SeekableStream::position_type max_comment = 0x10000;
const SeekableStream::position_type bufshift = 6;
const SeekableStream::position_type bufsize = max_comment >> bufshift;
unsigned char buffer[bufsize];
SeekableStream::position_type search_end = (max_comment < start_position) ? start_position - max_comment : 0;
SeekableStream::position_type position = start_position;
while (position != search_end) {
StreamBase::size_type to_read = std::min(bufsize, position - search_end);
position -= to_read;
istream.seek(position);
StreamBase::size_type size = istream.read(buffer, to_read);
unsigned char *p = buffer + size;
while (p != buffer) {
--p;
magic.m_value[3] = magic.m_value[2];
magic.m_value[2] = magic.m_value[1];
magic.m_value[1] = magic.m_value[0];
magic.m_value[0] = *p;
if (magic == zip_disk_trailer_magic) {
return position + (p - buffer);
}
}
}
return 0;
}
}
#endif