/**
* Resets the inflater so that a new stream can be decompressed. All
* pending input and output will be discarded.
*/
public void reset()
{
mode = nowrap ? DECODE_BLOCKS : DECODE_HEADER;
totalIn = totalOut = 0;
input.reset();
outputWindow.reset();
dynHeader = null;
litlenTree = null;
distTree = null;
isLastBlock = false;
adler.reset();
}
/**
* Decodes the deflated stream.
* @return false if more input is needed, or if finished.
* @exception DataFormatException if deflated stream is invalid.
*/
private bool decode()
{
switch (mode)
{
case DECODE_HEADER:
return decodeHeader();
case DECODE_DICT:
return decodeDict();
case DECODE_CHKSUM:
return decodeChksum();
case DECODE_BLOCKS:
if (isLastBlock)
{
if (nowrap)
{
mode = FINISHED;
return false;
}
else
{
input.skipToByteBoundary();
neededBits = 32;
mode = DECODE_CHKSUM;
return true;
}
}
int type = input.peekBits(3);
if (type < 0)
return false;
input.dropBits(3);
if ((type & 1) != 0)
isLastBlock = true;
switch (type >> 1)
{
case DeflaterConstants.STORED_BLOCK:
input.skipToByteBoundary();
mode = DECODE_STORED_LEN1;
break;
case DeflaterConstants.STATIC_TREES:
litlenTree = InflaterHuffmanTree.defLitLenTree;
distTree = InflaterHuffmanTree.defDistTree;
mode = DECODE_HUFFMAN;
break;
case DeflaterConstants.DYN_TREES:
dynHeader = new InflaterDynHeader();
mode = DECODE_DYN_HEADER;
break;
default:
throw new System.Exception("Unknown block type " + type);
}
return true;
case DECODE_STORED_LEN1:
{
if ((uncomprLen = input.peekBits(16)) < 0)
return false;
input.dropBits(16);
mode = DECODE_STORED_LEN2;
}
/* fall through */
goto case DECODE_STORED_LEN2;
case DECODE_STORED_LEN2:
{
int nlen = input.peekBits(16);
if (nlen < 0)
return false;
input.dropBits(16);
if (nlen != (uncomprLen ^ 0xffff))
throw new System.Exception("broken uncompressed block");
mode = DECODE_STORED;
}
/* fall through */
goto case DECODE_STORED;
case DECODE_STORED:
{
int more = outputWindow.copyStored(input, uncomprLen);
uncomprLen -= more;
if (uncomprLen == 0)
{
mode = DECODE_BLOCKS;
return true;
}
return !input.needsInput();
}
//goto case DECODE_DYN_HEADER;
case DECODE_DYN_HEADER:
if (!dynHeader.decode(input))
return false;
litlenTree = dynHeader.buildLitLenTree();
distTree = dynHeader.buildDistTree();
mode = DECODE_HUFFMAN;
/* fall through */
goto case DECODE_HUFFMAN;
case DECODE_HUFFMAN:
case DECODE_HUFFMAN_LENBITS:
case DECODE_HUFFMAN_DIST:
case DECODE_HUFFMAN_DISTBITS:
return decodeHuffman();
case FINISHED:
return false;
default:
throw new System.Exception();
}
}
/**
* Frees all objects allocated by the inflater. There's no reason
* to call this, since you can just rely on garbage collection (even
* for the Sun implementation). Exists only for compatibility
* with Sun's JDK, where the compressor allocates native memory.
* If you call any method (even reset) afterwards the behaviour is
* <i>undefined</i>.
*/
public void end()
{
outputWindow = null;
input = null;
dynHeader = null;
litlenTree = null;
distTree = null;
adler = null;
}