blast
public int blast(InputStream input,
OutputStream output)
throws IOException
Decode PKWare Compression Library stream.
Format notes:
- First byte is 0 if literals are uncoded or 1 if they are coded. Second
byte is 4, 5, or 6 for the number of extra bits in the distance code.
This is the base-2 logarithm of the dictionary size minus six.
- Compressed data is a combination of literals and length/distance pairs
terminated by an end code. Literals are either Huffman coded or
uncoded bytes. A length/distance pair is a coded length followed by a
coded distance to represent a string that occurs earlier in the
uncompressed data that occurs again at the current location.
- A bit preceding a literal or length/distance pair indicates which comes
next, 0 for literals, 1 for length/distance.
- If literals are uncoded, then the next eight bits are the literal, in the
normal bit order in the stream, i.e. no bit-reversal is needed. Similarly,
no bit reversal is needed for either the length extra bits or the distance
extra bits.
- Literal bytes are simply written to the output. A length/distance pair is
an instruction to copy previously uncompressed bytes to the output. The
copy is from distance bytes back in the output stream, copying for length
bytes.
- Distances pointing before the beginning of the output data are not
permitted.
- Overlapped copies, where the length is greater than the distance, are
allowed and common. For example, a distance of one and a length of 518
simply copies the last byte 518 times. A distance of four and a length of
twelve copies the last four bytes three times. A simple forward copy
ignoring whether the length is greater than the distance or not implements
this correctly.
- Parameters:
input - InputStream instanceoutput - OutputStream instance- Returns:
- status code
- Throws:
IOException