示例#1
0
        public void PrepareToDecodeERISANCode()
        {
            if (null == m_pProbERISA)
            {
                m_pProbERISA = new ErisaProbBase();
            }

            m_iLastSymbol = 0;
            for (int i = 0; i < 4; ++i)
            {
                m_bytLastSymbol[i] = 0;
            }

            m_pProbERISA.dwWorkUsed = 0;
            m_pProbERISA.epmBaseModel.Initialize();

            for (int i = 0; i < ErisaProbBase.SlotMax; ++i)
            {
                m_pProbERISA.ptrProbIndex[i] = new ErisaProbModel();
            }
            PrepareToDecodeERISACode();

            if (null == m_pNemesisBuf)
            {
                m_pNemesisBuf = new byte[Nemesis.BufSize];
            }
            if (null == m_pNemesisLookup)
            {
                m_pNemesisLookup = new NemesisPhraseLookup[0x100];
            }
            for (int i = 0; i < m_pNemesisBuf.Length; ++i)
            {
                m_pNemesisBuf[i] = 0;
            }
            for (int i = 0; i < m_pNemesisLookup.Length; ++i)
            {
                m_pNemesisLookup[i] = new NemesisPhraseLookup();
            }
            m_nNemesisIndex = 0;

            m_nNemesisLeft = 0;
            m_flagEOF      = false;
        }
示例#2
0
        public uint DecodeNemesisCodeBytes(byte[] ptrDst, uint nCount)
        {
            if (m_flagEOF)
            {
                return(0);
            }

            ErisaProbBase pBase    = m_pProbERISA;
            uint          nDecoded = 0;
            int           dst      = 0;
            byte          bytSymbol;

            while (nDecoded < nCount)
            {
                if (m_nNemesisLeft > 0)
                {
                    uint nNemesisCount = (uint)m_nNemesisLeft;
                    if (nNemesisCount > nCount - nDecoded)
                    {
                        nNemesisCount = nCount - nDecoded;
                    }
                    byte bytLastSymbol = m_pNemesisBuf[(m_nNemesisIndex - 1) & Nemesis.BufMask];

                    for (uint i = 0; i < nNemesisCount; ++i)
                    {
                        bytSymbol = bytLastSymbol;
                        if (m_nNemesisNext >= 0)
                        {
                            bytSymbol       = m_pNemesisBuf[m_nNemesisNext++];
                            m_nNemesisNext &= Nemesis.BufMask;
                        }
                        m_bytLastSymbol[m_iLastSymbol++] = bytSymbol;
                        m_iLastSymbol &= 3;

                        var phrase = m_pNemesisLookup[bytSymbol];
                        phrase.index[phrase.first] = (uint)m_nNemesisIndex;
                        phrase.first  = (phrase.first + 1) & Nemesis.IndexMask;
                        bytLastSymbol = bytSymbol;

                        m_pNemesisBuf[m_nNemesisIndex++] = bytSymbol;
                        m_nNemesisIndex &= Nemesis.BufMask;

                        ptrDst[dst++] = bytSymbol;
                    }
                    m_nNemesisLeft -= (int)nNemesisCount;
                    nDecoded       += nNemesisCount;
                    continue;
                }

                int            iDeg;
                ErisaProbModel pModel = pBase.epmBaseModel;
                for (iDeg = 0; iDeg < 4; ++iDeg)
                {
                    int iLast = m_bytLastSymbol[(m_iLastSymbol + 3 - iDeg) & 3]
                                >> ErisaProbBase.m_nShiftCount[iDeg];
                    if (pModel.SubModel[iLast].Symbol < 0)
                    {
                        break;
                    }
                    Debug.Assert((uint)pModel.SubModel[iLast].Symbol < pBase.dwWorkUsed);
                    pModel = pBase.ptrProbIndex[pModel.SubModel[iLast].Symbol];
                }
                int iSym = DecodeERISACodeIndex(pModel);
                if (iSym < 0)
                {
                    return(nDecoded);
                }
                int nSymbol   = pModel.SymTable[iSym].Symbol;
                int iSymIndex = pModel.IncreaseSymbol(iSym);

                bool fNemesis = false;
                if (nSymbol == ErisaProbModel.EscCode)
                {
                    if (pModel != pBase.epmBaseModel)
                    {
                        iSym = DecodeERISACodeIndex(pBase.epmBaseModel);
                        if (iSym < 0)
                        {
                            return(nDecoded);
                        }
                        nSymbol = pBase.epmBaseModel.SymTable[iSym].Symbol;
                        pBase.epmBaseModel.IncreaseSymbol(iSym);
                        if (nSymbol != ErisaProbModel.EscCode)
                        {
                            pModel.AddSymbol((short)nSymbol);
                            iSym = -1;
                        }
                        else
                        {
                            fNemesis = true;
                        }
                    }
                    else
                    {
                        fNemesis = true;
                    }
                }
                if (fNemesis)
                {
                    int nLength, nPhraseIndex;
                    nPhraseIndex = DecodeERISACode(m_pPhraseIndexProb);
                    if (nPhraseIndex == ErisaProbModel.EscCode)
                    {
                        m_flagEOF = true;
                        return(nDecoded);
                    }
                    if (0 == nPhraseIndex)
                    {
                        nLength = DecodeERISACode(m_pRunLenProb);
                    }
                    else
                    {
                        nLength = DecodeERISACode(m_pPhraseLenProb);
                    }
                    if (nLength == ErisaProbModel.EscCode)
                    {
                        return(nDecoded);
                    }
                    byte bytLastSymbol = m_pNemesisBuf[(m_nNemesisIndex - 1) & Nemesis.BufMask];
                    var  phrase        = m_pNemesisLookup[bytLastSymbol];
                    m_nNemesisLeft = nLength;
                    if (0 == nPhraseIndex)
                    {
                        m_nNemesisNext = -1;
                    }
                    else
                    {
                        m_nNemesisNext = (int)phrase.index[(phrase.first - nPhraseIndex) & Nemesis.IndexMask];
                        Debug.Assert(m_pNemesisBuf[m_nNemesisNext] == bytLastSymbol);
                        m_nNemesisNext = (m_nNemesisNext + 1) & Nemesis.BufMask;
                    }
                    continue;
                }
                bytSymbol = (byte)nSymbol;
                m_bytLastSymbol[m_iLastSymbol++] = bytSymbol;
                m_iLastSymbol &= 3;

                var ppl = m_pNemesisLookup[bytSymbol];
                ppl.index[ppl.first]             = (uint)m_nNemesisIndex;
                ppl.first                        = (ppl.first + 1) & Nemesis.IndexMask;
                m_pNemesisBuf[m_nNemesisIndex++] = bytSymbol;
                m_nNemesisIndex                 &= Nemesis.BufMask;

                ptrDst[dst++] = bytSymbol;
                nDecoded++;

                if ((pBase.dwWorkUsed < ErisaProbBase.SlotMax) && (iDeg < 4))
                {
                    int iSymbol = ((byte)nSymbol) >> ErisaProbBase.m_nShiftCount[iDeg];
                    Debug.Assert(iSymbol < ErisaProbModel.SubSortMax);
                    if (++pModel.SubModel[iSymbol].Occured >= ErisaProbBase.m_nNewProbLimit[iDeg])
                    {
                        int            i;
                        ErisaProbModel pParent = pModel;
                        pModel = pBase.epmBaseModel;
                        for (i = 0; i <= iDeg; ++i)
                        {
                            iSymbol = m_bytLastSymbol[(m_iLastSymbol + 3 - i) & 3]
                                      >> ErisaProbBase.m_nShiftCount[i];
                            if (pModel.SubModel[iSymbol].Symbol < 0)
                            {
                                break;
                            }
                            Debug.Assert((uint)pModel.SubModel[iSymbol].Symbol < pBase.dwWorkUsed);
                            pModel = pBase.ptrProbIndex[pModel.SubModel[iSymbol].Symbol];
                        }
                        if ((i <= iDeg) && (pModel.SubModel[iSymbol].Symbol < 0))
                        {
                            ErisaProbModel pNew = pBase.ptrProbIndex[pBase.dwWorkUsed];
                            pModel.SubModel[iSymbol].Symbol = (short)(pBase.dwWorkUsed++);

                            pNew.TotalCount = 0;
                            int j = 0;
                            for (i = 0; i < (int)pParent.SymbolSorts; ++i)
                            {
                                ushort wOccured = (ushort)(pParent.SymTable[i].Occured >> 4);
                                if (wOccured > 0 && (pParent.SymTable[i].Symbol != ErisaProbModel.EscCode))
                                {
                                    pNew.TotalCount         += wOccured;
                                    pNew.SymTable[j].Occured = wOccured;
                                    pNew.SymTable[j].Symbol  = pParent.SymTable[i].Symbol;
                                    j++;
                                }
                            }
                            pNew.TotalCount++;
                            pNew.SymTable[j].Occured = 1;
                            pNew.SymTable[j].Symbol  = ErisaProbModel.EscCode;
                            pNew.SymbolSorts         = ++j;

                            for (i = 0; i < ErisaProbModel.SubSortMax; ++i)
                            {
                                pNew.SubModel[i].Occured = 0;
                                pNew.SubModel[i].Symbol  = -1;
                            }
                        }
                    }
                }
            }
            return(nDecoded);
        }
示例#3
0
        public void PrepareToDecodeERISANCode()
        {
            if (null == m_pProbERISA)
                m_pProbERISA = new ErisaProbBase();

            m_iLastSymbol = 0;
            for (int i = 0; i < 4; ++i)
                m_bytLastSymbol[i] = 0;

            m_pProbERISA.dwWorkUsed = 0;
            m_pProbERISA.epmBaseModel.Initialize();

            for (int i = 0; i < ErisaProbBase.SlotMax; ++i)
            {
                m_pProbERISA.ptrProbIndex[i] = new ErisaProbModel();
            }
            PrepareToDecodeERISACode();

            if (null == m_pNemesisBuf)
            {
                m_pNemesisBuf = new byte[Nemesis.BufSize];
            }
            if (null == m_pNemesisLookup)
            {
                m_pNemesisLookup = new NemesisPhraseLookup[0x100];
            }
            for (int i = 0; i < m_pNemesisBuf.Length; ++i)
                m_pNemesisBuf[i] = 0;
            for (int i = 0; i < m_pNemesisLookup.Length; ++i)
                m_pNemesisLookup[i] = new NemesisPhraseLookup();
            m_nNemesisIndex = 0;

            m_nNemesisLeft = 0;
            m_flagEOF = false;
        }