// Copy up to length of bytes from input directly.
// This is used for uncompressed block.
public int CopyFrom(InputBuffer input, int length)
{
length = Math.Min(Math.Min(length, WindowSize - _bytesUsed), input.AvailableBytes);
int copied;
// We might need wrap around to copy all bytes.
int tailLen = WindowSize - _end;
if (length > tailLen)
{
// copy the first part
copied = input.CopyTo(_window, _end, tailLen);
if (copied == tailLen)
{
// only try to copy the second part if we have enough bytes in input
copied += input.CopyTo(_window, 0, length - tailLen);
}
}
else
{
// only one copy is needed if there is no wrap around.
copied = input.CopyTo(_window, _end, length);
}
_end = (_end + copied) & WindowMask;
_bytesUsed += copied;
return copied;
}
public GZipDecoder(InputBuffer input)
{
this.input = input;
Reset();
}
public GZipDecoder(InputBuffer input)
{
this.input = input;
Reset();
}
//
// This function will try to get enough bits from input and
// try to decode the bits.
// If there are no enought bits in the input, this function will return -1.
//
public int GetNextSymbol(InputBuffer input)
{
// Try to load 16 bits into input buffer if possible and get the bitBuffer value.
// If there aren't 16 bits available we will return all we have in the
// input buffer.
uint bitBuffer = input.TryLoad16Bits();
if (input.AvailableBits == 0)
{
// running out of input.
return -1;
}
// decode an element
int symbol = _table[bitBuffer & _tableMask];
if (symbol < 0)
{
// this will be the start of the binary tree
// navigate the tree
uint mask = (uint) 1 << _tableBits;
do
{
symbol = -symbol;
if ((bitBuffer & mask) == 0)
symbol = _left[symbol];
else
symbol = _right[symbol];
mask <<= 1;
} while (symbol < 0);
}
//
// If this code is longer than the # bits we had in the bit buffer (i.e.
// we read only part of the code), we can hit the entry in the table or the tree
// for another symbol. However the length of another symbol will not match the
// available bits count.
if (_codeLengthArray[symbol] > input.AvailableBits)
{
// We already tried to load 16 bits and maximum length is 15,
// so this means we are running out of input.
return -1;
}
input.SkipBits(_codeLengthArray[symbol]);
return symbol;
}
