mirror of
https://github.com/crskycode/GARbro.git
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339 lines
13 KiB
C#
339 lines
13 KiB
C#
//! \file ErisaNemesis.cs
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//! \date Tue Jan 19 18:24:23 2016
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//! \brief Erisa Nemesis encoding implementation.
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//
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using System;
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using System.Diagnostics;
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using System.IO;
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namespace GameRes.Formats.Entis
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{
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class NemesisDecodeContext : ProbDecodeContext
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{
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int m_iLastSymbol;
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int m_nNemesisLeft;
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int m_nNemesisNext;
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byte[] m_pNemesisBuf;
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int m_nNemesisIndex;
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bool m_flagEOF;
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ErisaProbBase m_pProbERISA;
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NemesisPhraseLookup[] m_pNemesisLookup;
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byte[] m_bytLastSymbol = new byte[4];
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public NemesisDecodeContext (uint buffer_size = 0x10000) : base (buffer_size)
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{
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m_flagEOF = false;
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}
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public void PrepareToDecodeERISANCode ()
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{
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if (null == m_pProbERISA)
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m_pProbERISA = new ErisaProbBase();
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m_iLastSymbol = 0;
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for (int i = 0; i < 4; ++i)
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m_bytLastSymbol[i] = 0;
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m_pProbERISA.dwWorkUsed = 0;
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m_pProbERISA.epmBaseModel.Initialize();
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for (int i = 0; i < ErisaProbBase.SlotMax; ++i)
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{
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m_pProbERISA.ptrProbIndex[i] = new ErisaProbModel();
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}
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PrepareToDecodeERISACode();
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if (null == m_pNemesisBuf)
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{
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m_pNemesisBuf = new byte[Nemesis.BufSize];
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}
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if (null == m_pNemesisLookup)
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{
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m_pNemesisLookup = new NemesisPhraseLookup[0x100];
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}
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for (int i = 0; i < m_pNemesisBuf.Length; ++i)
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m_pNemesisBuf[i] = 0;
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for (int i = 0; i < m_pNemesisLookup.Length; ++i)
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m_pNemesisLookup[i] = new NemesisPhraseLookup();
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m_nNemesisIndex = 0;
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m_nNemesisLeft = 0;
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m_flagEOF = false;
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}
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public override uint DecodeBytes (Array ptrDst, uint nCount)
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{
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return DecodeNemesisCodeBytes (ptrDst as byte[], 0, nCount);
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}
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public uint DecodeNemesisCodeBytes (byte[] ptrDst, int dst, uint nCount)
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{
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if (m_flagEOF)
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return 0;
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ErisaProbBase pBase = m_pProbERISA;
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uint nDecoded = 0;
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byte bytSymbol;
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while (nDecoded < nCount)
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{
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if (m_nNemesisLeft > 0)
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{
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uint nNemesisCount = (uint)m_nNemesisLeft;
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if (nNemesisCount > nCount - nDecoded)
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{
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nNemesisCount = nCount - nDecoded;
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}
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byte bytLastSymbol = m_pNemesisBuf[(m_nNemesisIndex - 1) & Nemesis.BufMask];
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for (uint i = 0; i < nNemesisCount; ++i)
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{
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bytSymbol = bytLastSymbol;
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if (m_nNemesisNext >= 0)
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{
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bytSymbol = m_pNemesisBuf[m_nNemesisNext++];
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m_nNemesisNext &= Nemesis.BufMask;
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}
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m_bytLastSymbol[m_iLastSymbol++] = bytSymbol;
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m_iLastSymbol &= 3;
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var phrase = m_pNemesisLookup[bytSymbol];
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phrase.index[phrase.first] = (uint)m_nNemesisIndex;
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phrase.first = (phrase.first + 1) & Nemesis.IndexMask;
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bytLastSymbol = bytSymbol;
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m_pNemesisBuf[m_nNemesisIndex++] = bytSymbol;
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m_nNemesisIndex &= Nemesis.BufMask;
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ptrDst[dst++] = bytSymbol;
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}
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m_nNemesisLeft -= (int)nNemesisCount;
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nDecoded += nNemesisCount;
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continue;
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}
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int iDeg;
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ErisaProbModel pModel = pBase.epmBaseModel;
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for (iDeg = 0; iDeg < 4; ++iDeg)
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{
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int iLast = m_bytLastSymbol[(m_iLastSymbol + 3 - iDeg) & 3]
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>> ErisaProbBase.m_nShiftCount[iDeg];
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if (pModel.SubModel[iLast].Symbol < 0)
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{
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break;
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}
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if ((uint)pModel.SubModel[iLast].Symbol >= pBase.dwWorkUsed)
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throw new InvalidFormatException ("Invalid Nemesis encoding sequence");
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pModel = pBase.ptrProbIndex[pModel.SubModel[iLast].Symbol];
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}
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int iSym = DecodeERISACodeIndex (pModel);
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if (iSym < 0)
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{
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return nDecoded;
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}
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int nSymbol = pModel.SymTable[iSym].Symbol;
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int iSymIndex = pModel.IncreaseSymbol (iSym);
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bool fNemesis = false;
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if (nSymbol == ErisaProbModel.EscCode)
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{
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if (pModel != pBase.epmBaseModel)
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{
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iSym = DecodeERISACodeIndex (pBase.epmBaseModel);
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if (iSym < 0)
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{
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return nDecoded;
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}
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nSymbol = pBase.epmBaseModel.SymTable[iSym].Symbol;
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pBase.epmBaseModel.IncreaseSymbol (iSym);
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if (nSymbol != ErisaProbModel.EscCode)
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{
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pModel.AddSymbol ((short)nSymbol);
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}
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else
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{
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fNemesis = true;
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}
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}
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else
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{
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fNemesis = true;
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}
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}
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if (fNemesis)
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{
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int nLength, nPhraseIndex;
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nPhraseIndex = DecodeERISACode (m_pPhraseIndexProb);
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if (nPhraseIndex == ErisaProbModel.EscCode)
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{
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m_flagEOF = true;
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return nDecoded;
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}
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if (0 == nPhraseIndex)
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{
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nLength = DecodeERISACode (m_pRunLenProb);
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}
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else
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{
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nLength = DecodeERISACode (m_pPhraseLenProb);
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}
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if (nLength == ErisaProbModel.EscCode)
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{
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return nDecoded;
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}
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byte bytLastSymbol = m_pNemesisBuf[(m_nNemesisIndex - 1) & Nemesis.BufMask];
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var phrase = m_pNemesisLookup[bytLastSymbol];
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m_nNemesisLeft = nLength;
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if (0 == nPhraseIndex)
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{
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m_nNemesisNext = -1;
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}
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else
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{
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m_nNemesisNext = (int)phrase.index[(phrase.first - nPhraseIndex) & Nemesis.IndexMask];
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if (m_pNemesisBuf[m_nNemesisNext] != bytLastSymbol)
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throw new InvalidFormatException ("Invalid Nemesis encoding sequence");
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m_nNemesisNext = (m_nNemesisNext + 1) & Nemesis.BufMask;
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}
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continue;
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}
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bytSymbol = (byte)nSymbol;
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m_bytLastSymbol[m_iLastSymbol++] = bytSymbol;
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m_iLastSymbol &= 3;
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var ppl = m_pNemesisLookup[bytSymbol];
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ppl.index[ppl.first] = (uint)m_nNemesisIndex;
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ppl.first = (ppl.first + 1) & Nemesis.IndexMask;
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m_pNemesisBuf[m_nNemesisIndex++] = bytSymbol;
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m_nNemesisIndex &= Nemesis.BufMask;
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ptrDst[dst++] = bytSymbol;
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nDecoded++;
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if ((pBase.dwWorkUsed < ErisaProbBase.SlotMax) && (iDeg < 4))
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{
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int iSymbol = bytSymbol >> ErisaProbBase.m_nShiftCount[iDeg];
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if (iSymbol >= ErisaProbModel.SubSortMax)
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throw new InvalidFormatException ("Invalid Nemesis encoding sequence");
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if (++pModel.SubModel[iSymbol].Occured >= ErisaProbBase.m_nNewProbLimit[iDeg])
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{
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int i;
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ErisaProbModel pParent = pModel;
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pModel = pBase.epmBaseModel;
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for (i = 0; i <= iDeg; ++i)
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{
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iSymbol = m_bytLastSymbol[(m_iLastSymbol + 3 - i) & 3]
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>> ErisaProbBase.m_nShiftCount[i];
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if (pModel.SubModel[iSymbol].Symbol < 0)
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{
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break;
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}
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if ((uint)pModel.SubModel[iSymbol].Symbol >= pBase.dwWorkUsed)
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throw new InvalidFormatException ("Invalid Nemesis encoding sequence");
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pModel = pBase.ptrProbIndex[pModel.SubModel[iSymbol].Symbol];
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}
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if ((i <= iDeg) && (pModel.SubModel[iSymbol].Symbol < 0))
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{
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ErisaProbModel pNew = pBase.ptrProbIndex[pBase.dwWorkUsed];
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pModel.SubModel[iSymbol].Symbol = (short)(pBase.dwWorkUsed++);
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pNew.TotalCount = 0;
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int j = 0;
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for (i = 0; i < (int)pParent.SymbolSorts; ++i)
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{
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ushort wOccured = (ushort)(pParent.SymTable[i].Occured >> 4);
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if (wOccured > 0 && (pParent.SymTable[i].Symbol != ErisaProbModel.EscCode))
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{
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pNew.TotalCount += wOccured;
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pNew.SymTable[j].Occured = wOccured;
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pNew.SymTable[j].Symbol = pParent.SymTable[i].Symbol;
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j++;
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}
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}
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pNew.TotalCount++;
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pNew.SymTable[j].Occured = 1;
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pNew.SymTable[j].Symbol = ErisaProbModel.EscCode;
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pNew.SymbolSorts = ++j;
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for (i = 0; i < ErisaProbModel.SubSortMax; ++i)
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{
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pNew.SubModel[i].Occured = 0;
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pNew.SubModel[i].Symbol = -1;
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}
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}
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}
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}
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}
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return nDecoded;
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}
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}
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internal class ErisaProbBase
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{
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public uint dwWorkUsed;
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public ErisaProbModel epmBaseModel = new ErisaProbModel();
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public ErisaProbModel[] ptrProbIndex = new ErisaProbModel[SlotMax];
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public const int SlotMax = 0x800;
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public static readonly int[] m_nShiftCount = { 1, 3, 4, 5 };
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public static readonly int[] m_nNewProbLimit = { 0x01, 0x08, 0x10, 0x20 };
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}
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internal static class Nemesis
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{
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public const int BufSize = 0x10000;
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public const int BufMask = 0xFFFF;
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public const int IndexLimit = 0x100;
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public const int IndexMask = 0xFF;
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}
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internal class NemesisPhraseLookup
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{
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public uint first;
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public uint[] index = new uint[Nemesis.IndexLimit];
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}
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internal class ErisaNemesisStream : InputProxyStream
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{
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NemesisDecodeContext m_decoder;
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int m_remaining;
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bool m_eof = false;
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public ErisaNemesisStream (Stream input, int output_length = 0) : base (input)
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{
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m_decoder = new NemesisDecodeContext();
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m_decoder.AttachInputFile (input);
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m_decoder.PrepareToDecodeERISANCode();
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m_remaining = output_length > 0 ? output_length : int.MaxValue;
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}
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public override int Read (byte[] buffer, int offset, int count)
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{
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int read = 0;
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if (!m_eof && m_remaining > 0)
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{
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uint chunk_size = (uint)Math.Min (count, m_remaining);
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read = (int)m_decoder.DecodeNemesisCodeBytes (buffer, offset, chunk_size);
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m_eof = read < count;
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m_remaining -= read;
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}
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return read;
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}
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public override bool CanSeek { get { return false; } }
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public override long Length { get { throw new NotSupportedException(); } }
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public override long Position {
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get { throw new NotSupportedException(); }
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set { throw new NotSupportedException(); }
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}
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public override long Seek (long offset, SeekOrigin origin)
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{
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throw new NotSupportedException();
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}
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}
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}
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