/// <summary>
/// Creates a new inflater.
/// </summary>
/// <param name="noHeader">
/// True if no RFC1950/Zlib header and footer fields are expected in the input data
///
/// This is used for GZIPed/Zipped input.
///
/// For compatibility with
/// Sun JDK you should provide one byte of input more than needed in
/// this case.
/// </param>
public Inflater(bool noHeader)
{
this.noHeader = noHeader;
this.adler = new Adler32();
input = new StreamManipulator();
outputWindow = new OutputWindow();
mode = noHeader ? DECODE_BLOCKS : DECODE_HEADER;
}
/// <summary>
/// Copy from input manipulator to internal window
/// </summary>
/// <param name="input">source of data</param>
/// <param name="length">length of data to copy</param>
/// <returns>the number of bytes copied</returns>
public int CopyStored(StreamManipulator input, int length)
{
length = Math.Min(Math.Min(length, WindowSize - windowFilled), input.AvailableBytes);
int copied;
int tailLen = WindowSize - windowEnd;
if (length > tailLen) {
copied = input.CopyBytes(window, windowEnd, tailLen);
if (copied == tailLen) {
copied += input.CopyBytes(window, 0, length - tailLen);
}
} else {
copied = input.CopyBytes(window, windowEnd, length);
}
windowEnd = (windowEnd + copied) & WindowMask;
windowFilled += copied;
return copied;
}
/// <summary>
/// Reads the next symbol from input. The symbol is encoded using the
/// huffman tree.
/// </summary>
/// <param name="input">
/// input the input source.
/// </param>
/// <returns>
/// the next symbol, or -1 if not enough input is available.
/// </returns>
public int GetSymbol(StreamManipulator input)
{
int lookahead, symbol;
if ((lookahead = input.PeekBits(9)) >= 0) {
if ((symbol = tree[lookahead]) >= 0) {
input.DropBits(symbol & 15);
return symbol >> 4;
}
int subtree = -(symbol >> 4);
int bitlen = symbol & 15;
if ((lookahead = input.PeekBits(bitlen)) >= 0) {
symbol = tree[subtree | (lookahead >> 9)];
input.DropBits(symbol & 15);
return symbol >> 4;
} else {
int bits = input.AvailableBits;
lookahead = input.PeekBits(bits);
symbol = tree[subtree | (lookahead >> 9)];
if ((symbol & 15) <= bits) {
input.DropBits(symbol & 15);
return symbol >> 4;
} else {
return -1;
}
}
} else {
int bits = input.AvailableBits;
lookahead = input.PeekBits(bits);
symbol = tree[lookahead];
if (symbol >= 0 && (symbol & 15) <= bits) {
input.DropBits(symbol & 15);
return symbol >> 4;
} else {
return -1;
}
}
}
