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;
}
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);
}
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;
}