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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 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/>.
*
*/
//=============================================================================
//
// MemoryStream does reading and writing over the buffer of bytes stored in
// memory. Currently has rather trivial implementation. Does not own a buffer
// itself, but works with the provided C-buffer pointer, which means that the
// buffer object *must* persist until stream is closed.
//
// VectorStream is a specialized implementation that works with std::vector.
// Unlike base MemoryStream provides continiously resizing buffer for writing.
// TODO: separate StringStream for reading & writing String object?
//
//=============================================================================
#ifndef AGS_SHARED_UTIL_MEMORY_STREAM_H
#define AGS_SHARED_UTIL_MEMORY_STREAM_H
#include "common/std/vector.h"
#include "ags/shared/util/data_stream.h"
#include "ags/shared/util/string.h"
namespace AGS3 {
namespace AGS {
namespace Shared {
class MemoryStream : public DataStream {
public:
// Construct memory stream in the read-only mode over a const C-buffer;
// reading will never exceed buf_sz bytes;
// buffer must persist in memory until the stream is closed.
MemoryStream(const uint8_t *cbuf, size_t buf_sz, DataEndianess stream_endianess = kLittleEndian);
// Construct memory stream in the chosen mode over a given C-buffer;
// neither reading nor writing will ever exceed buf_sz bytes;
// buffer must persist in memory until the stream is closed.
MemoryStream(uint8_t *buf, size_t buf_sz, StreamWorkMode mode, DataEndianess stream_endianess = kLittleEndian);
~MemoryStream() override {}
void Close() override;
bool Flush() override;
// Is stream valid (underlying data initialized properly)
bool IsValid() const override;
// Is end of stream
bool EOS() const override;
// Total length of stream (if known)
soff_t GetLength() const override;
// Current position (if known)
soff_t GetPosition() const override;
bool CanRead() const override;
bool CanWrite() const override;
bool CanSeek() const override;
size_t Read(void *buffer, size_t size) override;
int32_t ReadByte() override;
size_t Write(const void *buffer, size_t size) override;
int32_t WriteByte(uint8_t b) override;
soff_t Seek(soff_t offset, StreamSeek origin) override;
protected:
const uint8_t *_cbuf = nullptr; // readonly buffer ptr
size_t _buf_sz = 0u; // hard buffer limit
size_t _len = 0u; // calculated length of stream
const StreamWorkMode _mode;
size_t _pos = 0u; // current stream pos
private:
uint8_t *_buf = nullptr; // writeable buffer ptr
};
class VectorStream : public MemoryStream {
public:
// Construct memory stream in the read-only mode over a const std::vector;
// vector must persist in memory until the stream is closed.
VectorStream(const std::vector<uint8_t> &cbuf, DataEndianess stream_endianess = kLittleEndian);
// Construct memory stream in the chosen mode over a given std::vector;
// vector must persist in memory until the stream is closed.
VectorStream(std::vector<uint8_t> &buf, StreamWorkMode mode, DataEndianess stream_endianess = kLittleEndian);
~VectorStream() override {}
void Close() override;
bool CanRead() const override;
bool CanWrite() const override;
size_t Write(const void *buffer, size_t size) override;
int32_t WriteByte(uint8_t b) override;
private:
std::vector<uint8_t> *_vec = nullptr; // writeable vector (may be null)
};
} // namespace Shared
} // namespace AGS
} // namespace AGS3
#endif
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