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/* 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 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.
*
*/
#ifndef MACVENTURE_CONTAINER_H
#define MACVENTURE_CONTAINER_H
#include "macventure/macventure.h"
#include "common/file.h"
#include "common/bitstream.h"
namespace MacVenture {
struct ItemGroup {
uint32 bitOffset; //It's really uint24
uint32 offset; //It's really uint24
uint32 lengths[64];
};
typedef uint32 ContainerHeader;
class Container {
public:
Container(const char *filename) {
_filename = Common::String(filename);
if (!_file.open(filename))
error("Could not open %s", filename);
_res = _file.readStream(_file.size());
_header = _res->readUint32BE();
_simplified = false;
if (!(_header & 0x80000000)) {
// Is simplified container
_simplified = true;
int dataLen = _res->size() - sizeof(_header);
_lenObjs = _header;
_numObjs = dataLen / _lenObjs;
} else {
_header &= 0x7fffffff;
_res->seek(_header, SEEK_SET);
_numObjs = _res->readUint16BE();
for (uint i = 0; i < 15; ++i)
_huff[i] = _res->readUint16BE();
for (uint i = 0; i < 16; ++i)
_lens[i] = _res->readByte();
// Read groups
uint numGroups = _numObjs / 64;
if ((_numObjs % 64) > 0)
numGroups++;
for (uint i = 0; i < numGroups; ++i) {
ItemGroup group;
// Place myself in the correct position to read group
_res->seek(_header + (i * 6) + 0x30, SEEK_SET);
byte b1, b2, b3;
b1 = _res->readByte();
b2 = _res->readByte();
b3 = _res->readByte();
group.bitOffset = (b1 << 16) + (b2 << 8) + (b3 << 0);
b1 = _res->readByte();
b2 = _res->readByte();
b3 = _res->readByte();
group.offset = (b1 << 16) + (b2 << 8) + (b3 << 0);
// Place the bit reader in the correct position
// group.bitOffset indicates the offset from the start of the subHeader
_res->seek(_header + (group.bitOffset >> 3), SEEK_SET);
uint32 bits = group.bitOffset & 7;
for (uint j = 0; j < 64; ++j) {
uint32 length = 0;
//debug("reading mask from address %x", _res->pos());
uint32 mask = _res->readUint32BE();
mask >>= (16 - bits);
mask &= 0xFFFF;
debug(11, "Load mask of object &%d:%d is %x", i, j, mask);
_res->seek(-4, SEEK_CUR);
// Look in the Huffman table
int x = 0;
for (x = 0; x < 16; x++) {
if (_huff[x] > mask) break;
}
// I will opt to copy the code from webventure,
// But according to the docs, this call should suffice:
// length = bitStream.getBits(_lens[x]);
// The problem is that _lens[] usually contains values larger
// Than 32, so we have to read them with the method below
//This code below, taken from the implementation, seems to give the same results.
uint32 bitSize = _lens[x];
bits += bitSize & 0xF;
if (bits & 0x10) {
bits &= 0xF;
_res->seek(2, SEEK_CUR);
}
bitSize >>= 4;
if (bitSize) {
length = _res->readUint32BE();
_res->seek(-4, SEEK_CUR);
bitSize--;
if (bitSize == 0) length = 0;
else length >>= (32 - bitSize) - bits;
length &= (1 << bitSize) - 1;
length |= 1 << bitSize;
bits += bitSize;
if (bits & 0x10) {
bits &= 0xF;
_res->seek(2, SEEK_CUR);
}
}
group.lengths[j] = length;
debug(11, "Load legth of object %d:%d is %d", i, j, length);
}
_groups.push_back(group);
}
}
}
~Container() {
if (_file.isOpen())
_file.close();
if (_res)
delete _res;
}
public:
/**
* Must be called before retrieving an object.
*/
uint32 getItemByteSize(uint32 id) {
if (_simplified) {
return _lenObjs;
} else {
uint32 groupID = (id >> 6);
uint32 objectIndex = id & 0x3f; // Index within the group
return _groups[groupID].lengths[objectIndex];
}
}
/**
* getItemByteSize should be called before this one
*/
Common::SeekableReadStream *getItem(uint32 id) {
if (_simplified) {
_res->seek((id * _lenObjs) + sizeof(_header), SEEK_SET);
} else {
uint32 groupID = (id >> 6);
uint32 objectIndex = id & 0x3f; // Index within the group
uint32 offset = 0;
for (uint i = 0; i < objectIndex; i++) {
offset += _groups[groupID].lengths[i];
}
_res->seek(_groups[groupID].offset + offset + sizeof(_header), SEEK_SET);
}
Common::SeekableReadStream *res = _res->readStream(getItemByteSize(id) * 2);
return res;
}
protected:
bool _simplified;
uint _lenObjs; // In the case of simple container, lenght of an object
uint _numObjs;
ContainerHeader _header;
uint16 _huff[15]; // huffman masks
uint8 _lens[16]; // huffman lengths
Common::Array<ItemGroup> _groups;
Common::String _filename;
Common::File _file;
Common::SeekableReadStream *_res;
};
} // End of namespace MacVenture
#endif
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