mirror of
https://github.com/bsnes-emu/bsnes.git
synced 2025-04-02 10:42:14 -04:00
79b939e1c7
It's been a while, so here is a new release of bsnes. Unfortunately I don't have a full changelog this time. Most of the work went into stabilizing libsnes (which is used by the experimental .NET, Cocoa and Python UIs; as well as by Richard Bannister's OS X port). The Windows binary package now comes with all three variants included: bsnes.exe, the standard version that casual users should run; bsnes-debugger.exe, for SNES programmers and ROM hackers only; and bsnes-accurate.exe, which should not be used by anybody, ever. In all seriousness, bsnes-accurate.exe is bsnes with the dot-based S-PPU renderer. It's twice as slow as the normal build, and you won't really notice any differences except in Air Strike Patrol. It's there for the curious and for any SNES programmers who want to try making some really awesome video demos. Changelog: * OS X port builds once again; now requires gcc44 from Macports * libsnes API finalized * fixed a bug with S-CPU debugger breakpoints * various source cleanup
143 lines
3.3 KiB
C++
143 lines
3.3 KiB
C++
/*
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Copyright (C) 2002 Andrea Mazzoleni ( http://advancemame.sf.net )
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Copyright (C) 2001-4 Igor Pavlov ( http://www.7-zip.org )
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License version 2.1 as published by the Free Software Foundation.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __COMPRESSION_RANGECODER_H
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#define __COMPRESSION_RANGECODER_H
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#include "inbyte.h"
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namespace NCompression {
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namespace NArithmetic {
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const UINT32 kNumTopBits = 24;
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const UINT32 kTopValue = (1 << kNumTopBits);
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class CRangeDecoder
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{
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public:
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NStream::CInByte m_Stream;
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UINT32 m_Range;
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UINT32 m_Code;
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UINT32 m_Word;
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void Normalize()
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{
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while (m_Range < kTopValue)
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{
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m_Code = (m_Code << 8) | m_Stream.ReadByte();
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m_Range <<= 8;
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}
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}
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void Init(ISequentialInStream *aStream)
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{
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m_Stream.Init(aStream);
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m_Code = 0;
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m_Range = UINT32(-1);
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for(int i = 0; i < 5; i++)
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m_Code = (m_Code << 8) | m_Stream.ReadByte();
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}
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UINT32 GetThreshold(UINT32 aTotal)
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{
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return (m_Code) / ( m_Range /= aTotal);
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}
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void Decode(UINT32 aStart, UINT32 aSize, UINT32 aTotal)
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{
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m_Code -= aStart * m_Range;
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m_Range *= aSize;
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Normalize();
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}
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/*
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UINT32 DecodeDirectBitsDiv(UINT32 aNumTotalBits)
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{
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m_Range >>= aNumTotalBits;
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UINT32 aThreshold = m_Code / m_Range;
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m_Code -= aThreshold * m_Range;
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Normalize();
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return aThreshold;
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}
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UINT32 DecodeDirectBitsDiv2(UINT32 aNumTotalBits)
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{
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if (aNumTotalBits <= kNumBottomBits)
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return DecodeDirectBitsDiv(aNumTotalBits);
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UINT32 aResult = DecodeDirectBitsDiv(aNumTotalBits - kNumBottomBits) << kNumBottomBits;
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return (aResult | DecodeDirectBitsDiv(kNumBottomBits));
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}
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*/
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UINT32 DecodeDirectBits(UINT32 aNumTotalBits)
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{
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UINT32 aRange = m_Range;
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UINT32 aCode = m_Code;
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UINT32 aResult = 0;
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for (UINT32 i = aNumTotalBits; i > 0; i--)
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{
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aRange >>= 1;
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/*
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aResult <<= 1;
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if (aCode >= aRange)
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{
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aCode -= aRange;
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aResult |= 1;
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}
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*/
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UINT32 t = (aCode - aRange) >> 31;
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aCode -= aRange & (t - 1);
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// aRange = aRangeTmp + ((aRange & 1) & (1 - t));
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aResult = (aResult << 1) | (1 - t);
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if (aRange < kTopValue)
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{
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aCode = (aCode << 8) | m_Stream.ReadByte();
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aRange <<= 8;
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}
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}
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m_Range = aRange;
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m_Code = aCode;
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return aResult;
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}
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UINT32 DecodeBit(UINT32 aSize0, UINT32 aNumTotalBits)
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{
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UINT32 aNewBound = (m_Range >> aNumTotalBits) * aSize0;
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UINT32 aSymbol;
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if (m_Code < aNewBound)
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{
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aSymbol = 0;
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m_Range = aNewBound;
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}
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else
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{
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aSymbol = 1;
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m_Code -= aNewBound;
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m_Range -= aNewBound;
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}
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Normalize();
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return aSymbol;
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}
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UINT64 GetProcessedSize() {return m_Stream.GetProcessedSize(); }
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};
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}}
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#endif
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