scummvm/engines/mm/shared/xeen/cc_archive.cpp
2024-05-01 21:07:04 -07:00

236 lines
6.7 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "common/file.h"
#include "common/memstream.h"
#include "common/textconsole.h"
#include "mm/shared/xeen/cc_archive.h"
namespace MM {
namespace Shared {
namespace Xeen {
uint16 BaseCCArchive::convertNameToId(const Common::Path &resourceName) {
Common::String name = resourceName.baseName();
if (resourceName.empty() || name.hasSuffix("."))
return 0xffff;
name.toUppercase();
// Check if a resource number is being directly specified
if (name.size() == 4) {
char *endPtr;
uint16 num = (uint16)strtol(name.c_str(), &endPtr, 16);
if (!*endPtr)
return num;
}
const byte *msgP = (const byte *)name.c_str();
int total = *msgP++;
for (; *msgP; total += *msgP++) {
// Rotate the bits in 'total' right 7 places
total = (total & 0x007F) << 9 | (total & 0xFF80) >> 7;
}
return total;
}
void BaseCCArchive::loadIndex(Common::SeekableReadStream &stream) {
int count = stream.readUint16LE();
size_t size = count * 8;
// Read in the data for the archive's index
byte *rawIndex = new byte[size];
if (stream.read(rawIndex, size) != size) {
delete[] rawIndex;
error("Failed to read %zu bytes from CC file", size);
}
// Decrypt the index
int seed = 0xac;
for (int i = 0; i < count * 8; ++i, seed += 0x67) {
rawIndex[i] = (byte)((((rawIndex[i] << 2) | (rawIndex[i] >> 6)) + seed) & 0xff);
}
// Extract the index data into entry structures
_index.resize(count);
const byte *entryP = &rawIndex[0];
for (int idx = 0; idx < count; ++idx, entryP += 8) {
CCEntry entry;
entry._id = READ_LE_UINT16(entryP);
entry._offset = READ_LE_UINT32(entryP + 2) & 0xffffff;
entry._size = READ_LE_UINT16(entryP + 5);
assert(!entryP[7]);
_index[idx] = entry;
}
delete[] rawIndex;
}
void BaseCCArchive::saveIndex(Common::WriteStream &stream) {
// Fill up the data for the index entries into a raw data block
byte *rawIndex = new byte[_index.size() * 8];
byte b;
byte *entryP = rawIndex;
for (uint i = 0; i < _index.size(); ++i, entryP += 8) {
CCEntry &entry = _index[i];
WRITE_LE_UINT16(&entryP[0], entry._id);
WRITE_LE_UINT32(&entryP[2], entry._writeOffset);
WRITE_LE_UINT16(&entryP[5], entry._size);
entryP[7] = 0;
}
// Encrypt the index
int seed = 0xac;
for (uint i = 0; i < _index.size() * 8; ++i, seed += 0x67) {
b = (rawIndex[i] - seed) & 0xff;
b = (byte)((b >> 2) | (b << 6));
assert(rawIndex[i] == (byte)((((b << 2) | (b >> 6)) + seed) & 0xff));
rawIndex[i] = b;
}
// Write out the number of entries and the encrypted index data
stream.writeUint16LE(_index.size());
stream.write(rawIndex, _index.size() * 8);
delete[] rawIndex;
}
bool BaseCCArchive::hasFile(const Common::Path &path) const {
CCEntry ccEntry;
return getHeaderEntry(path, ccEntry);
}
bool BaseCCArchive::getHeaderEntry(const Common::Path &resourceName, CCEntry &ccEntry) const {
return getHeaderEntry(convertNameToId(resourceName), ccEntry);
}
bool BaseCCArchive::getHeaderEntry(uint16 id, CCEntry &ccEntry) const {
// Loop through the index
for (uint i = 0; i < _index.size(); ++i) {
if (_index[i]._id == id) {
ccEntry = _index[i];
return true;
}
}
// Could not find an entry
return false;
}
const Common::ArchiveMemberPtr BaseCCArchive::getMember(const Common::Path &path) const {
if (!hasFile(path))
return Common::ArchiveMemberPtr();
return Common::ArchiveMemberPtr(new Common::GenericArchiveMember(path, *this));
}
int BaseCCArchive::listMembers(Common::ArchiveMemberList &list) const {
// CC files don't maintain the original filenames, so we can't list it
return 0;
}
/*------------------------------------------------------------------------*/
CCArchive::CCArchive(const Common::Path &filename, bool encoded) :
BaseCCArchive(), _filename(filename), _encoded(encoded) {
Common::File f;
if (!f.open(filename, SearchMan))
error("Could not open file - %s", filename.toString(Common::Path::kNativeSeparator).c_str());
loadIndex(f);
}
CCArchive::CCArchive(const Common::Path &filename, const Common::String &prefix,
bool encoded) : BaseCCArchive(), _filename(filename),
_prefix(prefix), _encoded(encoded) {
_prefix.toLowercase();
Common::File f;
if (!f.open(filename, SearchMan))
error("Could not open file - %s", filename.toString(Common::Path::kNativeSeparator).c_str());
loadIndex(f);
}
CCArchive::~CCArchive() {
}
bool CCArchive::getHeaderEntry(const Common::Path &resourceName, Shared::Xeen::CCEntry &ccEntry) const {
Common::String resName = resourceName.baseName();
if (!_prefix.empty() && resName.contains('|')) {
resName.toLowercase();
Common::String prefix = _prefix + "|";
if (!strncmp(resName.c_str(), prefix.c_str(), prefix.size()))
// Matching CC prefix, so strip it off and allow processing to
// continue onto the base getHeaderEntry method
resName = Common::String(resName.c_str() + prefix.size());
else
// Not matching prefix, so don't allow a match
return false;
}
return BaseCCArchive::getHeaderEntry(resourceName.getParent().appendComponent(resName), ccEntry);
}
Common::SeekableReadStream *CCArchive::createReadStreamForMember(const Common::Path &path) const {
Shared::Xeen::CCEntry ccEntry;
if (getHeaderEntry(path, ccEntry)) {
// Open the correct CC file
Common::File f;
if (!f.open(_filename))
error("Could not open CC file");
// Read in the data for the specific resource
if (!f.seek(ccEntry._offset))
error("Failed to seek to %d bytes in CC file", ccEntry._offset);
byte *data = (byte *)malloc(ccEntry._size);
if (f.read(data, ccEntry._size) != ccEntry._size) {
free(data);
error("Failed to read %hu bytes in CC file", ccEntry._size);
}
if (_encoded) {
// Decrypt the data
for (int i = 0; i < ccEntry._size; ++i)
data[i] ^= 0x35;
}
// Return the data as a stream
return new Common::MemoryReadStream(data, ccEntry._size, DisposeAfterUse::YES);
}
return nullptr;
}
} // namespace Xeen
} // namespace Shared
} // namespace MM