Initial community commit

Src/external_dependencies/openmpt-trunk/include/ancient/src/OutputStream.cpp

@@ -0,0 +1,124 @@
+/* Copyright (C) Teemu Suutari */
+
+#include <cstring>
+
+#include <algorithm>
+
+#include "OutputStream.hpp"
+// for exceptions
+#include "Decompressor.hpp"
+#include "common/Common.hpp"
+#include "common/OverflowCheck.hpp"
+
+
+namespace ancient::internal
+{
+
+ForwardOutputStream::ForwardOutputStream(Buffer &buffer,size_t startOffset,size_t endOffset) :
+	_bufPtr(buffer.data()),
+	_startOffset(startOffset),
+	_currentOffset(startOffset),
+	_endOffset(endOffset)
+{
+	if (_startOffset>_endOffset || _currentOffset>buffer.size() || _endOffset>buffer.size()) throw Decompressor::DecompressionError();
+}
+
+ForwardOutputStream::~ForwardOutputStream()
+{
+	// nothing needed
+}
+
+void ForwardOutputStream::writeByte(uint8_t value)
+{
+	if (_currentOffset>=_endOffset) throw Decompressor::DecompressionError();
+	_bufPtr[_currentOffset++]=value;
+}
+
+uint8_t ForwardOutputStream::copy(size_t distance,size_t count)
+{
+	if (!distance || OverflowCheck::sum(_startOffset,distance)>_currentOffset || OverflowCheck::sum(_currentOffset,count)>_endOffset) throw Decompressor::DecompressionError();
+	uint8_t ret=0;
+	for (size_t i=0;i<count;i++,_currentOffset++)
+		ret=_bufPtr[_currentOffset]=_bufPtr[_currentOffset-distance];
+	return ret;
+}
+
+uint8_t ForwardOutputStream::copy(size_t distance,size_t count,const Buffer &prevBuffer)
+{
+	if (!distance || OverflowCheck::sum(_currentOffset,count)>_endOffset) throw Decompressor::DecompressionError();
+	size_t prevCount=0;
+	uint8_t ret=0;
+	if (OverflowCheck::sum(_startOffset,distance)>_currentOffset)
+	{
+		size_t prevSize=prevBuffer.size();
+		if (_startOffset+distance>_currentOffset+prevSize) throw Decompressor::DecompressionError(); 
+		size_t prevDist=_startOffset+distance-_currentOffset;
+		prevCount=std::min(count,prevDist);
+		const uint8_t *prev=&prevBuffer[prevSize-prevDist];
+		for (size_t i=0;i<prevCount;i++,_currentOffset++)
+			ret=_bufPtr[_currentOffset]=prev[i];
+	}
+	for (size_t i=prevCount;i<count;i++,_currentOffset++)
+		ret=_bufPtr[_currentOffset]=_bufPtr[_currentOffset-distance];
+	return ret;
+}
+
+uint8_t ForwardOutputStream::copy(size_t distance,size_t count,uint8_t defaultChar)
+{
+	if (!distance || OverflowCheck::sum(_currentOffset,count)>_endOffset) throw Decompressor::DecompressionError();
+	size_t prevCount=0;
+	uint8_t ret=0;
+	if (OverflowCheck::sum(_startOffset,distance)>_currentOffset)
+	{
+		prevCount=std::min(count,_startOffset+distance-_currentOffset);
+		for (size_t i=0;i<prevCount;i++,_currentOffset++)
+			ret=_bufPtr[_currentOffset]=defaultChar;
+	}
+	for (size_t i=prevCount;i<count;i++,_currentOffset++)
+		ret=_bufPtr[_currentOffset]=_bufPtr[_currentOffset-distance];
+	return ret;
+}
+
+const uint8_t *ForwardOutputStream::history(size_t distance) const
+{
+	if (distance>_currentOffset) throw Decompressor::DecompressionError();
+	return &_bufPtr[_currentOffset-distance];
+}
+
+void ForwardOutputStream::produce(const uint8_t *src,size_t bytes)
+{
+	if (OverflowCheck::sum(_currentOffset,bytes)>_endOffset) throw Decompressor::DecompressionError();
+	std::memcpy(&_bufPtr[_currentOffset],src,bytes);
+	_currentOffset+=bytes;
+}
+
+BackwardOutputStream::BackwardOutputStream(Buffer &buffer,size_t startOffset,size_t endOffset) :
+	_bufPtr(buffer.data()),
+	_startOffset(startOffset),
+	_currentOffset(endOffset),
+	_endOffset(endOffset)
+{
+	if (_startOffset>_endOffset || _currentOffset>buffer.size() || _endOffset>buffer.size()) throw Decompressor::DecompressionError();
+}
+
+BackwardOutputStream::~BackwardOutputStream()
+{
+	// nothing needed
+}
+
+void BackwardOutputStream::writeByte(uint8_t value)
+{
+	if (_currentOffset<=_startOffset) throw Decompressor::DecompressionError();
+	_bufPtr[--_currentOffset]=value;
+}
+
+uint8_t BackwardOutputStream::copy(size_t distance,size_t count)
+{
+	if (!distance || OverflowCheck::sum(_startOffset,count)>_currentOffset || OverflowCheck::sum(_currentOffset,distance)>_endOffset) throw Decompressor::DecompressionError();
+	uint8_t ret=0;
+	for (size_t i=0;i<count;i++,--_currentOffset)
+		ret=_bufPtr[_currentOffset-1]=_bufPtr[_currentOffset+distance-1];
+	return ret;
+}
+
+}