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https://github.com/bsnes-emu/bsnes.git
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9ca1e259cb
A thank you to everyone who helped test the RC to ensure stability. I've uploaded the official v064 release to Google Code. The most important change in this release is the cycle-based PPU renderer; but due to performance reasons the scanline-based renderer remains the default in the Windows binary. If you want to try out the cycle-based renderer, you will need to compile from source for now. Another major change is the introduction of libsnes, which allows one to build bsnes as a shared library that can be used from other programming languages. It is intended both to create a regression testing framework, and to provide API stability for the various projects that use the bsnes core. While I can't guarantee the API to libsnes won't change, I will properly revision it and do everything I can to avoid changing it if possible.
73 lines
1.9 KiB
C++
73 lines
1.9 KiB
C++
#ifndef __COMPRESSION_BITCODER_H
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#define __COMPRESSION_BITCODER_H
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#include "rngcoder.h"
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namespace NCompression {
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namespace NArithmetic {
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const int kNumBitModelTotalBits = 11;
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const UINT32 kBitModelTotal = (1 << kNumBitModelTotalBits);
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const int kNumMoveReducingBits = 2;
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/////////////////////////////
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// CBitModel
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template <int aNumMoveBits>
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class CBitModel
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{
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public:
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UINT32 m_Probability;
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void UpdateModel(UINT32 aSymbol)
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{
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/*
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m_Probability -= (m_Probability + ((aSymbol - 1) & ((1 << aNumMoveBits) - 1))) >> aNumMoveBits;
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m_Probability += (1 - aSymbol) << (kNumBitModelTotalBits - aNumMoveBits);
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*/
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if (aSymbol == 0)
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m_Probability += (kBitModelTotal - m_Probability) >> aNumMoveBits;
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else
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m_Probability -= (m_Probability) >> aNumMoveBits;
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}
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public:
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void Init() { m_Probability = kBitModelTotal / 2; }
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};
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template <int aNumMoveBits>
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class CBitDecoder: public CBitModel<aNumMoveBits>
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{
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public:
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UINT32 Decode(CRangeDecoder *aRangeDecoder)
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{
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UINT32 aNewBound = (aRangeDecoder->m_Range >> kNumBitModelTotalBits) * CBitModel<aNumMoveBits>::m_Probability;
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if (aRangeDecoder->m_Code < aNewBound)
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{
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aRangeDecoder->m_Range = aNewBound;
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CBitModel<aNumMoveBits>::m_Probability += (kBitModelTotal - CBitModel<aNumMoveBits>::m_Probability) >> aNumMoveBits;
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if (aRangeDecoder->m_Range < kTopValue)
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{
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aRangeDecoder->m_Code = (aRangeDecoder->m_Code << 8) | aRangeDecoder->m_Stream.ReadByte();
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aRangeDecoder->m_Range <<= 8;
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}
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return 0;
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}
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else
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{
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aRangeDecoder->m_Range -= aNewBound;
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aRangeDecoder->m_Code -= aNewBound;
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CBitModel<aNumMoveBits>::m_Probability -= (CBitModel<aNumMoveBits>::m_Probability) >> aNumMoveBits;
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if (aRangeDecoder->m_Range < kTopValue)
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{
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aRangeDecoder->m_Code = (aRangeDecoder->m_Code << 8) | aRangeDecoder->m_Stream.ReadByte();
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aRangeDecoder->m_Range <<= 8;
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}
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return 1;
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}
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}
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};
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}}
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#endif
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