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XEEN: Fixes for encryption and resource offsets in save files

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This commit is contained in:
Paul Gilbert 2018-01-14 14:16:58 -05:00
parent a506a8f7eb
commit 700bcc73e1
3 changed files with 44 additions and 14 deletions
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29
engines/xeen/files.cpp
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@ -88,12 +88,13 @@ void BaseCCArchive::loadIndex(Common::SeekableReadStream &stream) {
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._offset);
WRITE_LE_UINT32(&entryP[2], entry._writeOffset);
WRITE_LE_UINT16(&entryP[5], entry._size);
entryP[7] = 0;
}
@ -101,8 +102,11 @@ void BaseCCArchive::saveIndex(Common::WriteStream &stream) {
// Encrypt the index
int seed = 0xac;
for (uint i = 0; i < _index.size() * 8; ++i, seed += 0x67) {
byte b = (rawIndex[i] - seed) & 0xff;
rawIndex[i] = (byte)((b >> 2) | (b << 6));
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
@ -489,19 +493,19 @@ void SaveArchive::save(Common::WriteStream &s) {
_party->synchronize(sPty);
pty.finalize();
// First caclculate file offsets for each resource, since replaced resources
// will shift file offsets for even the succeeding unchanged resources
for (uint idx = 1, pos = _index[0]._offset + _index[0]._size; idx < _index.size(); ++idx) {
_index[idx]._offset = pos;
pos += _index[idx]._size;
// First caclculate new offsets and total filesize
_dataSize = _index.size() * 8 + 2;
for (uint idx = 0; idx < _index.size(); ++idx) {
_index[idx]._writeOffset = (idx == 0) ? _dataSize :
_index[idx - 1]._writeOffset + _index[idx - 1]._size;
_dataSize += _index[idx]._size;
}
// Write out the size of the save archive
_dataSize = _index.back()._offset + _index.back()._size;
s.writeUint32LE(_dataSize);
// Save out the index
saveIndex(s);
SubWriteStream dataStream(&s);
saveIndex(dataStream);
// Save out each resource in turn
for (uint idx = 0; idx < _index.size(); ++idx) {
@ -511,7 +515,8 @@ void SaveArchive::save(Common::WriteStream &s) {
entry->read(data, entry->size());
// Write it out to the savegame
s.write(data, entry->size());
assert(dataStream.pos() == _index[idx]._writeOffset);
dataStream.write(data, entry->size());
delete[] data;
delete entry;
}