scummvm/engines/myst3/archive.cpp

119 lines
3.2 KiB
C++

/* ResidualVM - A 3D game interpreter
*
* ResidualVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the AUTHORS
* file distributed with this source distribution.
*
* This program 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.
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include "engines/myst3/archive.h"
#include "common/debug.h"
#include "common/memstream.h"
namespace Myst3 {
void Archive::_decryptHeader(Common::SeekableReadStream &inStream, Common::WriteStream &outStream) {
static const uint32 addKey = 0x3C6EF35F;
static const uint32 multKey = 0x0019660D;
inStream.seek(0);
uint32 size = inStream.readUint32LE();
bool encrypted = size > 1000000;
inStream.seek(0);
if (encrypted) {
uint32 decryptedSize = size ^ addKey;
uint32 currentKey = 0;
for (uint i = 0; i < decryptedSize; i++) {
currentKey += addKey;
outStream.writeUint32LE(inStream.readUint32LE() ^ currentKey);
currentKey *= multKey;
}
} else {
for (uint i = 0; i < size; i++) {
outStream.writeUint32LE(inStream.readUint32LE());
}
}
}
void Archive::_readDirectory() {
Common::MemoryWriteStreamDynamic buf(DisposeAfterUse::YES);
_decryptHeader(_file, buf);
Common::MemoryReadStream directory(buf.getData(), buf.size());
directory.skip(sizeof(uint32));
while (directory.pos() + 4 < directory.size()) {
DirectoryEntry entry(this);
if (_multipleRoom)
entry.readFromStream(directory, 0);
else
entry.readFromStream(directory, _roomName);
_directory.push_back(entry);
}
}
void Archive::dumpToFiles() {
for (uint i = 0; i < _directory.size(); i++) {
_directory[i].dumpToFiles(_file);
}
}
Common::MemoryReadStream *Archive::dumpToMemory(uint32 offset, uint32 size) {
_file.seek(offset);
return static_cast<Common::MemoryReadStream *>(_file.readStream(size));
}
const DirectorySubEntry *Archive::getDescription(const char *room, uint32 index, uint16 face, DirectorySubEntry::ResourceType type) {
for (uint i = 0; i < _directory.size(); i++) {
if (_directory[i].getIndex() == index
&& !strcmp(_directory[i].getRoom(), room)) {
return _directory[i].getItemDescription(face, type);
}
}
return 0;
}
bool Archive::open(const char *fileName, const char *room) {
// Copy the room name if provided
// If the room name is not provided, it is assumed that
// we are opening a multi-room archive
_multipleRoom = room == 0;
if (!_multipleRoom)
Common::strlcpy(_roomName, room, sizeof(_roomName));
if (_file.open(fileName)) {
_readDirectory();
return true;
}
return false;
}
void Archive::close() {
_directory.clear();
_file.close();
}
} // end of namespace Myst3