/////////////////////////////////////////////////////////////////////
// Reads the next symbol from input. The symbol is encoded using the huffman tree.
/////////////////////////////////////////////////////////////////////
private Int32 ReadSymbol
(
InflateTree Tree
)
{
// fill the buffer to a maximum of 32 bits
for (; BitCount <= 24; BitCount += 8)
{
// read next byte from read buffer
Int32 OneByte = ReadByte();
// end of file
if (OneByte < 0)
{
break;
}
// append to the bit buffer
BitBuffer |= (UInt32)(OneByte << BitCount);
}
// loop through the decode tree
Int32 Next, Mask;
for (Mask = Tree.ActiveBitMask, Next = Tree.ActiveTree[(Int32)BitBuffer & (Mask - 1)];
Next > 0 && Mask < 0x10000; Next = (BitBuffer & Mask) == 0 ? Tree.ActiveTree[Next] : Tree.ActiveTree[Next + 1], Mask <<= 1)
{
;
}
// error
if (Next >= 0)
{
throw new ApplicationException("Error decoding the compressed bit stream (decoding tree error)");
}
// invert the symbol plus bit count
Next = ~Next;
// extract the number of bits
Int32 Bits = Next & 15;
// remove the bits from the bit buffer
BitBuffer >>= Bits;
BitCount -= Bits;
// error
if (BitCount < 0)
{
throw new ApplicationException("Error decoding the compressed bit stream (premature end of file)");
}
// exit with symbol
return(Next >> 4);
}
/// <summary>
/// Initializes a new instance of the <see cref="InflateMethod"/> class.
/// </summary>
protected InflateMethod()
{
// allocate buffers
_readBuffer = new byte[ReadBufSize];
_writeBuffer = new byte[WriteBufSize];
_bitLengthArray = new byte[MaxBitLengthCodes];
_literalDistanceArray = new byte[MaxLiteralCodes + MaxDistanceCodes];
_bitLengthTree = new InflateTree(TreeType.BitLen);
_literalTree = new InflateTree(TreeType.Literal);
_distanceTree = new InflateTree(TreeType.Distance);
}
////////////////////////////////////////////////////////////////////
// Constructor
////////////////////////////////////////////////////////////////////
public InflateMethod()
{
// allocate buffers
ReadBuffer = new Byte[ReadBufSize];
WriteBuffer = new Byte[WriteBufSize];
BitLengthArray = new Byte[MaxBitLengthCodes];
LiteralDistanceArray = new Byte[MaxLiteralCodes + MaxDistanceCodes];
BitLengthTree = new InflateTree(TreeType.BitLen);
LiteralTree = new InflateTree(TreeType.Literal);
DistanceTree = new InflateTree(TreeType.Distance);
return;
}
/// <summary>
/// Reads the next symbol from input. The symbol is encoded using the huffman tree.
/// </summary>
/// <param name="tree">The tree.</param>
/// <returns></returns>
/// <exception cref="UZipDotNet.Exception">
/// Error decoding the compressed bit stream (decoding tree error)
/// or
/// Error decoding the compressed bit stream (premature end of file)
/// </exception>
private int ReadSymbol(InflateTree tree)
{
// fill the buffer to a maximum of 32 bits
for (; _bitCount <= 24; _bitCount += 8)
{
// read next byte from read buffer
int oneByte = ReadByte();
// end of file
if (oneByte < 0)
{
break;
}
// append to the bit buffer
_bitBuffer |= (uint)(oneByte << _bitCount);
}
// loop through the decode tree
int next, mask;
for (mask = tree.ActiveBitMask, next = tree.ActiveTree[(int)_bitBuffer & (mask - 1)];
next > 0 && mask < 0x10000;
next = (_bitBuffer & mask) == 0 ? tree.ActiveTree[next] : tree.ActiveTree[next + 1], mask <<= 1)
{
}
// error
if (next >= 0)
{
throw new Exception("Error decoding the compressed bit stream (decoding tree error)");
}
// invert the symbol plus bit count
next = ~next;
// extract the number of bits
int bits = next & 15;
// remove the bits from the bit buffer
_bitBuffer >>= bits;
_bitCount -= bits;
// error
if (_bitCount < 0)
{
throw new Exception("Error decoding the compressed bit stream (premature end of file)");
}
// exit with symbol
return(next >> 4);
}
/// <summary>
/// Reads the next symbol from input. The symbol is encoded using the huffman tree.
/// </summary>
/// <param name="tree">The tree.</param>
/// <returns></returns>
/// <exception cref="UZipDotNet.Exception">
/// Error decoding the compressed bit stream (decoding tree error)
/// or
/// Error decoding the compressed bit stream (premature end of file)
/// </exception>
private int ReadSymbol(InflateTree tree)
{
// fill the buffer to a maximum of 32 bits
for (; _bitCount <= 24; _bitCount += 8)
{
// read next byte from read buffer
int oneByte = ReadByte();
// end of file
if (oneByte < 0) break;
// append to the bit buffer
_bitBuffer |= (uint)(oneByte << _bitCount);
}
// loop through the decode tree
int next, mask;
for (mask = tree.ActiveBitMask, next = tree.ActiveTree[(int) _bitBuffer & (mask - 1)];
next > 0 && mask < 0x10000;
next = (_bitBuffer & mask) == 0 ? tree.ActiveTree[next] : tree.ActiveTree[next + 1], mask <<= 1)
{
}
// error
if (next >= 0) throw new Exception("Error decoding the compressed bit stream (decoding tree error)");
// invert the symbol plus bit count
next = ~next;
// extract the number of bits
int bits = next & 15;
// remove the bits from the bit buffer
_bitBuffer >>= bits;
_bitCount -= bits;
// error
if (_bitCount < 0) throw new Exception("Error decoding the compressed bit stream (premature end of file)");
// exit with symbol
return (next >> 4);
}
/// <summary>
/// Initializes a new instance of the <see cref="InflateMethod"/> class.
/// </summary>
protected InflateMethod()
{
// allocate buffers
_readBuffer = new byte[ReadBufSize];
_writeBuffer = new byte[WriteBufSize];
_bitLengthArray = new byte[MaxBitLengthCodes];
_literalDistanceArray = new byte[MaxLiteralCodes + MaxDistanceCodes];
_bitLengthTree = new InflateTree(TreeType.BitLen);
_literalTree = new InflateTree(TreeType.Literal);
_distanceTree = new InflateTree(TreeType.Distance);
}
