David Roundy wrote:
On Fri, Jun 29, 2007 at 07:39:28PM +0100, Andrew Coppin wrote:
Now I have a problem. It's easy enough to pass the entire data stream through an RLE decoder and feed that to the Huffman table deserialize function, and it will give be back the table. But I now have *no clue* where the table ends in the original stream!
Sounds to me like you want a parsing monad. Generally, when you want state, you want a monad, and the field of parsing monads is pretty mature. You can either write up a monad of your own, or use one of the existing ones (parsec, frisby, read).
Am I missing something or why wouldn't encode, decode :: String -> String encode = encodeRLE . encodeHuffman decode = decodeHuffman . decodeRLE do the job? This is probably what Andrew intends to do in his Java version. Note that this not only RLE-encodes the Huffman table but also (needlessly) the data stream. In case you only want to RLE the table, a simple Word32 field tracking the size of the Huffman table should be enough. Regards, apfelmus