BAG ARCHIVE FILE FORMAT V1.1
by Jeff Connelly

The main goal of bag archives is to provide a simple and efficant way to
combine many files into one.  For that reason, it is extreamly simple.

The header is at the beginning of the file:
OFFSET             Count TYPE   Description
0000h                  3 char   ID='BAG'
0003h                  2 char   Version, ID='11'

There is one file block for each file:
OFFSET             Count TYPE   Description
0000h                  1 dword  File length in bytes
0004h                  1 byte   Filename length
????h                  ? char   Filename
????h                  ? char   File contents

At the very end of the file is:
OFFSET             Count TYPE   Description
0000h                  1 char   EOF marker, ID=1A

A file length of zero in a file block indicates a special file that will be
used as a description.  Directorys are also stored in the filename field:
    Filename='> dirname' means change current directory to 'dirname'.
For example,
Filename='> JEFF'
Filename='> COMPUTER'
Filename='> BAG'
Would make the directory be JEFF\COMPUTER\BAG.  Files are put in the current
directory.

The files contents is not always raw data, it can be compressed.  A
four-byte
signature can specifiy the compression scheme:
---- Compression ----
LZW     LZW encoded (note extra space at end)
RLEn    RLE method N (1 to 4) encoded
HUFF    Huffman encoded
LZHF    LZHUF encoded (LZSS + Arithmetic) (Note - the authors of LZHUF to
        not allow using is for any commicial purpose)
LZAR    LZARI encoded (LZSS + Huffman)
WCOD    Word coded -- text only
If no signature is found it is assumed to be raw data.

The word coding compression is as follows:
* Initalize dictionary (max. size FFFF)
* Loop until end-of-file
  * Read a space-delimited word from the input stream
  * Search for the word in the dictionary
    * If it is not there, add it to the first free space and output location
      of where in the dictionary the word was added as a 16-bit integer.
    * If it is there, output the location of where it is as a 16-bit
integer.
* Write dictionary at end of file.  Each word is null-terminated, whole
  dictionary is double-null terminated.
This means that each word will be encoded as 2 bytes.

The last character is an end-of-file character to insure the whole file was
recived when transfering this archive.