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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 COMMON_MEMSTREAM_H
#define COMMON_MEMSTREAM_H
#include "common/stream.h"
#include "common/types.h"
#include "common/util.h"
namespace Common {
/**
* Simple memory based 'stream', which implements the ReadStream interface for
* a plain memory block.
*/
class MemoryReadStream : public SeekableReadStream {
private:
const byte * const _ptrOrig;
const byte *_ptr;
const uint32 _size;
uint32 _pos;
DisposeAfterUse::Flag _disposeMemory;
bool _eos;
public:
/**
* This constructor takes a pointer to a memory buffer and a length, and
* wraps it. If disposeMemory is true, the MemoryReadStream takes ownership
* of the buffer and hence free's it when destructed.
*/
MemoryReadStream(const byte *dataPtr, uint32 dataSize, DisposeAfterUse::Flag disposeMemory = DisposeAfterUse::NO) :
_ptrOrig(dataPtr),
_ptr(dataPtr),
_size(dataSize),
_pos(0),
_disposeMemory(disposeMemory),
_eos(false) {}
~MemoryReadStream() {
if (_disposeMemory)
free(const_cast<byte *>(_ptrOrig));
}
uint32 read(void *dataPtr, uint32 dataSize);
bool eos() const { return _eos; }
void clearErr() { _eos = false; }
int32 pos() const { return _pos; }
int32 size() const { return _size; }
bool seek(int32 offs, int whence = SEEK_SET);
};
/**
* This is a MemoryReadStream subclass which adds non-endian
* read methods whose endianness is set on the stream creation.
*/
class MemoryReadStreamEndian : public MemoryReadStream, public ReadStreamEndian {
public:
MemoryReadStreamEndian(const byte *buf, uint32 len, bool bigEndian)
: MemoryReadStream(buf, len), ReadStreamEndian(bigEndian) {}
};
/**
* Simple memory based 'stream', which implements the WriteStream interface for
* a plain memory block.
*/
class MemoryWriteStream : public WriteStream {
private:
const uint32 _bufSize;
protected:
byte *_ptr;
uint32 _pos;
bool _err;
public:
MemoryWriteStream(byte *buf, uint32 len) : _ptr(buf), _bufSize(len), _pos(0), _err(false) {}
uint32 write(const void *dataPtr, uint32 dataSize) {
// Write at most as many bytes as are still available...
if (dataSize > _bufSize - _pos) {
dataSize = _bufSize - _pos;
// We couldn't write all the data => set error indicator
_err = true;
}
memcpy(_ptr, dataPtr, dataSize);
_ptr += dataSize;
_pos += dataSize;
return dataSize;
}
uint32 pos() const { return _pos; }
uint32 size() const { return _bufSize; }
virtual bool err() const { return _err; }
virtual void clearErr() { _err = false; }
};
/**
* MemoryWriteStream subclass with ability to set stream position indicator.
*/
class SeekableMemoryWriteStream : public MemoryWriteStream {
private:
byte *_ptrOrig;
public:
SeekableMemoryWriteStream(byte *buf, uint32 len) : MemoryWriteStream(buf, len), _ptrOrig(buf) {}
uint32 seek(uint32 offset, int whence = SEEK_SET) {
switch (whence) {
case SEEK_END:
// SEEK_END works just like SEEK_SET, only 'reversed',
// i.e. from the end.
offset = size() + offset;
// Fall through
case SEEK_SET:
_ptr = _ptrOrig + offset;
_pos = offset;
break;
case SEEK_CUR:
_ptr += offset;
_pos += offset;
break;
}
// Post-Condition
if (_pos > size()) {
_pos = size();
_ptr = _ptrOrig + _pos;
}
return _pos;
}
};
/**
* A sort of hybrid between MemoryWriteStream and Array classes. A stream
* that grows as it's written to.
*/
class MemoryWriteStreamDynamic : public WriteStream {
protected:
uint32 _capacity;
uint32 _size;
byte *_ptr;
byte *_data;
uint32 _pos;
DisposeAfterUse::Flag _disposeMemory;
void ensureCapacity(uint32 new_len) {
if (new_len <= _capacity)
return;
byte *old_data = _data;
_capacity = MAX(new_len + 32, _capacity * 2);
_data = (byte *)malloc(_capacity);
_ptr = _data + _pos;
if (old_data) {
// Copy old data
memcpy(_data, old_data, _size);
free(old_data);
}
_size = new_len;
}
public:
MemoryWriteStreamDynamic(DisposeAfterUse::Flag disposeMemory = DisposeAfterUse::NO) : _capacity(0), _size(0), _ptr(0), _data(0), _pos(0), _disposeMemory(disposeMemory) {}
~MemoryWriteStreamDynamic() {
if (_disposeMemory)
free(_data);
}
uint32 write(const void *dataPtr, uint32 dataSize) {
ensureCapacity(_pos + dataSize);
memcpy(_ptr, dataPtr, dataSize);
_ptr += dataSize;
_pos += dataSize;
if (_pos > _size)
_size = _pos;
return dataSize;
}
uint32 pos() const { return _pos; }
uint32 size() const { return _size; }
byte *getData() { return _data; }
bool seek(int32 offset, int whence = SEEK_SET);
};
} // End of namespace Common
#endif
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