Commander Keen 4-6 file formats

// All multi-byte ints are little-endian.

graph_head = { graph offset }, graph length
graph length = 3 byte int // Matches length of egagraph file.
graph offset = 3 byte int 

graph_dict = { huffman node }
huffman node = node side, node side // Left, right.
node side = node value, node type
node value = byte
node type = leaf | node // Byte: 0 = leaf, else = node.

egagraph = { chunk }
egagraph = unmasked picture table chunk with header,
    masked picture table chunk with header,
    sprite table chunk with header,
    font a chunk with header,
    font b chunk with header,
    font c chunk with header,
    { unmasked picture chunk with header }, // Count from unmasked picture table.
    { masked picture chunk with header }, // Count from masked picture table.
    { sprite chunk with header }, // Count from sprite table.
    unmasked 8x8 tiles chunk without header, // One chunk for all tiles.
    masked 8x8 tiles chunk without header, // One chunk for all tiles.
    { unmasked 16x16 tile chunk without header },
    { masked 16x16 tile chunk without header },
    { text etc }
chunk without header = huffman encoded chunk
chunk with header = chunk decompressed length, huffman encoded chunk
chunk decompressed length = 4 byte int

picture table = { picture table entry }
picture table entry = width_pixels_divided_by_8, height_pixels
width_pixels_divided_by_8 = 2 byte int
height_pixels = 2 byte int

sprite table = { sprite table entry } // 18 bytes each.
sprite table entry = width_div_by_8, // All are 2 byte ints.
    height,
    x offset,
    y offset,
    clip left,
    clip top,
    clip right,
    clip bottom,
    shifts

image = picture | tile | sprite
unmasked image = red plane, green plane, blue plane, intensity plane
masked image = red plane, green plane, blue plane, intensity plane, mask plane

map_head = rlew key, { map header offset }
rlew key = 2 bytes
map header offset = 4 byte int // 0 means no map in this slot.

gamemaps = "TED5v1.0", { map }
map = map planes, map header
map header = background plane offset, // 38 bytes.
    foreground plane offset,
    sprite plane offset,
    background plane length,
    foreground plane length,
    sprite plane length,
    tile count width,
    tile count height,
    map name
plane offset = 4 byte int
plane length = 2 byte int
tile count = 2 byte int
map name = 16 bytes asciiz
map planes = background carmackized plane,
    foreground carmackized plane,
    sprite carmackized plane
carmackized plane = carmackized decompressed length, carmackized data
carmackized decompressed length = 2 byte int
carmackized data = carmack compressed(rlew plane)
rlew plane = rlew decompresed length, rlew data
rlew decompressed length = 2 byte int
rlew data = rlew compressed(decompressed plane)
decompressed plane = { map plane row }
map plane row = { map plane element }
map plane element = 2 byte int