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MIO0 Binary Encoding Specification
Written by BGNG of Godspeed, 06/27/04
=====================================

Data Member Data Type Size
---------------------------------------------------

Identifier Str 4 Bytes
Destination Data Size UInt 4 Bytes
Compressed Data Offset UInt 4 Bytes
Uncompressed Data Offset UInt 4 Bytes
Data Map Prefixes Bits Unspecified
Compressed Data LDPairs Unspecified
Uncompressed Data Bytes Unspecified

*The Identifer is the 4-byte string "MIO0"

*UInts are stored as Big-Endian
*Offsets are base 0
*The bytes decoded tell your program when to stop
*LDPairs are 4/12-bit LZ77 length/distance pairs.

Notes:
======
LZ77 is a compression algorithm based on a series of headers,
compressed "pairs" and raw data. The headers are a series of
bits that, obviously, are either 1's or 0's corresponding to
the next piece of data being raw or compressed, respectively.

If it's 1, just pull the next byte of uncompressed data. If
it's 0, read the next two bytes of compressed data. These
bytes are a 16-bit pair of values, where these values are 4
bits then 12 bits.

The 12-bit value is a Distance value that tells the decoder
how many bytes backwards in the previously decoded data to
go from the end of the decoded data, minus 1. Add 1 to this
value when you decode it.

The 4-bit value is a Length value that tells how many bytes
to read from the Distance position which are to be copied
to the end of the output file, minus 3. Add 3 to this value
when you decode it.

Simply keep track of the current Header, Pair and Raw
offsets in the file you're decoding and you're good to go.
For encoding, it's simply a matter of checking an 18-byte
forward-read buffer with the previous 4096 bytes of the
file, looking for the longest match. If the length of the
match is greater than 2, then the data is compressed. Else,
it's included raw.

Sample File:
============

000000 4D494F300000002C 000000150000001F MIO0...,........
000010 FFAFFBFB40000200 0700130021002254 ....@.......!."T

000020 6865207261696E20 4D65207374617973 he rain Me stays
000030 206D6C79206F6E20 74706C2E mly on tpl.

Identifier: 4D494F30 ("MIO0")
Destination Data Size: 0000002C (44 bytes)
Compressed Data Offset: 00000015
Uncompressed Data Offset: 0000001F
Data Map Prefixes: FFAFFBFB40
(11111111 10101111 11111011 11111011 01000000)

Compressed Data: 0002 0007 0013 0021 0022
(3, 3; 3, 8; 3, 20; 3, 34; 3, 35)
Uncompressed Data:
The rain Me stays mly on tpl.

Output:
The rain in Maine stays mainly on the plain.

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