private unsafe HRESULT CodeSpec(byte *memStream, uint size)
{
switch (mDecoderStatus)
{
case kStatus.Finished:
return(HRESULT.S_OK);
case kStatus.Error:
return(HRESULT.S_FALSE);
case kStatus.NeedInit:
//_inStream.Init();
if (!PPMD.Ppmd7z_RangeDec_Init(mRangeDecoder))
{
mDecoderStatus = kStatus.Error;
return(HRESULT.S_FALSE);
}
mDecoderStatus = kStatus.Normal;
PPMD.Ppmd7_Init(mState, mSettingOrder);
break;
}
/* if (mLength.HasValue) */
{
var rem = mLength - mPosition;
if (size > rem)
{
size = (uint)rem;
}
}
uint i;
int sym = 0;
for (i = 0; i != size; i++)
{
sym = PPMD.Ppmd7_DecodeSymbol(mState, mRangeDecoder);
if (mExceededInput || sym < 0)
{
break;
}
memStream[i] = (byte)sym;
}
mPosition += i;
if (mExceededInput)
{
mDecoderStatus = kStatus.Error;
return(HRESULT.E_FAIL);
}
if (sym < 0)
{
mDecoderStatus = (sym < -1) ? kStatus.Error : kStatus.Finished;
}
return(HRESULT.S_OK);
}
protected override void Dispose(bool isDisposing)
{
if (isDisposing)
{
mInput?.Dispose();
PPMD.Ppmd7_Free(mState, mAlloc);
}
}
public PpmdDecoderStream(Stream input, byte[] settings, long length)
{
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
if (settings == default(byte[]))
{
throw new ArgumentNullException(nameof(settings));
}
if (settings.Length != 5)
{
throw new InvalidDataException();
}
if (length < 0)
{
throw new ArgumentOutOfRangeException(nameof(length));
}
mInput = input;
mLength = length;
mSettingOrder = settings[0];
if (mSettingOrder < PPMD.PPMD7_MIN_ORDER || mSettingOrder > PPMD.PPMD7_MAX_ORDER)
{
throw new InvalidDataException();
}
mSettingMemory = (uint)settings[1] | ((uint)settings[2] << 8) | ((uint)settings[3] << 16) | ((uint)settings[4] << 24);
if (mSettingMemory < PPMD.PPMD7_MIN_MEM_SIZE || mSettingMemory > PPMD.PPMD7_MAX_MEM_SIZE)
{
throw new InvalidDataException();
}
mRangeDecoder = new PPMD.CPpmd7z_RangeDec();
PPMD.Ppmd7z_RangeDec_CreateVTable(mRangeDecoder);
mRangeDecoder.Stream = new PPMD.IByteIn {
Read = x => checked ((byte)ReadByte())
};
PPMD.Ppmd7_Construct(mState);
if (!PPMD.Ppmd7_Alloc(mState, mSettingMemory, mAlloc))
{
throw new OutOfMemoryException();
}
}