scummvm/common/concatstream.h
2022-11-29 04:30:36 +01:00

68 lines
2.1 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/>.
*
*/
#ifndef COMMON_CONCATSTREAM_H
#define COMMON_CONCATSTREAM_H
#include "common/array.h"
#include "common/ptr.h"
#include "common/stream.h"
namespace Common {
/*
* ConcatReadStream provides access to a virtually concatenated stream.
*
* Manipulating the parent stream directly /will/ mess up a concatstream.
*
* Assumptions:
* - number of streams is small so iterating through array sized by N is cheap
* - size of streams doesn't change
*/
class ConcatReadStream : public SeekableReadStream {
private:
typedef Common::Array<Common::SharedPtr<Common::SeekableReadStream>> ParentStreamArray;
ParentStreamArray _parentStreams;
Common::Array<int64> _sizes;
Common::Array<int64> _startOffsets;
uint32 _totalSize, _linearPos;
uint32 _volume, _volumePos;
bool _err, _eos;
public:
ConcatReadStream(ParentStreamArray parentStreams);
int64 pos() const override { return _linearPos; }
int64 size() const override { return _totalSize; }
bool eos() const override { return _eos; }
bool err() const override { return _err; }
void clearErr() override {
_err = false;
_eos = false;
}
bool seek(int64 offset, int whence = SEEK_SET) override;
uint32 read(void *dataPtr, uint32 dataSize) override;
bool seekToVolume(int volume, int64 offset);
};
}
#endif // COMMON_CONCATSTREAM_H