scummvm/engines/got/utils/res_archive.cpp
2025-01-21 22:58:24 +01:00

147 lines
3.9 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 "got/utils/compression.h"
#include "got/utils/res_archive.h"
namespace Got {
static const char *RES_FILENAME = "gotres.dat";
void resInit() {
ResArchive *a = new ResArchive();
SearchMan.add("Res", a);
}
void ResHeader::load(Common::SeekableReadStream *src) {
char buf[10];
src->read(buf, 9);
buf[9] = '\0';
_name = buf;
_offset = src->readUint32LE();
_size = src->readUint32LE();
_originalSize = src->readUint32LE();
_key = src->readUint16LE();
}
ResArchive::ResArchive() {
Common::File f;
if (!f.open(RES_FILENAME))
error("Could not open %s", RES_FILENAME);
// Read in header data and decrypt it
byte buf[RES_MAX_ENTRIES * RES_HEADER_ENTRY_SIZE];
if (f.read(buf, RES_MAX_ENTRIES * RES_HEADER_ENTRY_SIZE) !=
(RES_MAX_ENTRIES * RES_HEADER_ENTRY_SIZE))
error("Could not read in resource headers");
decrypt(buf, RES_MAX_ENTRIES * RES_HEADER_ENTRY_SIZE, 128);
// Load headers
Common::MemoryReadStream hdrData(buf, RES_MAX_ENTRIES * RES_HEADER_ENTRY_SIZE);
for (int i = 0; i < RES_MAX_ENTRIES; ++i) {
ResHeader hdr;
hdr.load(&hdrData);
if (!(hdr._offset == 0 && hdr._size == 0))
_headers.push_back(hdr);
}
}
void ResArchive::decrypt(byte *buf, size_t len, byte key) const {
for (size_t i = 0; i < len; ++i)
*buf++ ^= key++;
}
int ResArchive::indexOf(const Common::String &name) const {
for (uint i = 0; i < _headers.size(); ++i) {
if (_headers[i]._name.equalsIgnoreCase(name))
return i;
}
return -1;
}
bool ResArchive::hasFile(const Common::Path &path) const {
return indexOf(path.baseName()) != -1;
}
int ResArchive::listMembers(Common::ArchiveMemberList &list) const {
int count = 0;
for (uint i = 0; i < _headers.size(); ++i) {
list.push_back(Common::ArchiveMemberList::value_type(
new Common::GenericArchiveMember(_headers[i]._name, *this)));
++count;
}
return count;
}
const Common::ArchiveMemberPtr ResArchive::getMember(const Common::Path &path) const {
if (!hasFile(path))
return Common::ArchiveMemberPtr();
return Common::ArchiveMemberPtr(new Common::GenericArchiveMember(path, *this));
}
Common::SeekableReadStream *ResArchive::createReadStreamForMember(const Common::Path &path) const {
// Get the index of the header entry for this file
const int hdrIndex = indexOf(path.baseName());
if (hdrIndex == -1)
return nullptr;
Common::File f;
if (!f.open(RES_FILENAME))
error("Error reading resource");
// Set up buffers
const ResHeader &hdr = _headers[hdrIndex];
byte *buf = (byte *)malloc(hdr._size);
f.seek(hdr._offset);
if (f.read(buf, hdr._size) != hdr._size)
error("Error reading resource");
// Decrypt if necessary
if (hdr._key != 0) {
byte *temp = buf;
buf = (byte *)malloc(hdr._originalSize);
lzssDecompress(temp, buf);
free(temp);
}
return new Common::MemoryReadStream(buf, hdr._originalSize,
DisposeAfterUse::YES);
}
void ResArchive::lzssDecompress(const byte *src, byte *dest) const {
const uint16 size = READ_LE_UINT16(src);
assert(READ_LE_UINT16(src + 2) == 1);
src += 4;
decompressLzss(src, dest, size);
}
} // namespace Got