DAT

In the context of Chip's Challenge, DAT or .dat is the file format which Chip's Challenge 1 level sets are commonly stored in, named for the CHIPS.DAT file containing the levels for MSCC. The .dat extension is short for "data" and commonly used on data files with ad-hoc formats; it is not specific to Chip's Challenge.

Since the release of CCTools, the format is sometimes referred to as CCL or .ccl, short for "Chip's Challenge levels". For people who have ChipEdit, which does not provide a way to open CCL files "normally", simply change the extension back to .dat, or type the file name manually when in the Open dialog.

Structure

The format is a relatively simple binary structure. All fields are little-endian.

File header

Offset	Bytes	Content
$00	4	Magic number, identifying the file format. MSCC will reject the file if this is not $0002AAAC. Tile World will also accept $0102AAAC as meaning a level set using Lynx rules. The pgchip modification expects $0003aaac.
$04	2	Number of levels in the file.

Levels begin at offset $06, immediately following the header.

Level structure

Offset	Bytes	Content
$00	2	Length of this level in bytes, not including this field.
$02	2	Level number.
$04	2	Time limit, in seconds. Zero indicates the level is untimed. Every official version of the game has a three-digit timer, so values over 999 are uncommon.
$06	2	Required number of chips. This may be less than the number of chips in the level, in which case the extras will be optional, or it may be more, in which case the chip socket will be impossible to open.
$08	2	Unclear. Must always be 0 or 1. The original levels all have this set to 1. Possibly once indicated whether the level data was compressed or not.
$0a	2	Length of top layer, in bytes.
$0c	varies	Contents of top layer; see below.
varies	2	Length of bottom layer, in bytes.
varies	varies	Contents of bottom layer; see below.
varies	2	Total length of all metadata chunks, in bytes; see below. MSCC crashes if there are more than 1152 bytes of metadata.
varies	varies	Zero or more metadata chunks; see below.

Level contents

The level is encoded as two layers, top and bottom. Every CC1 level is 32×32, so each layer contains exactly 1024 tiles. If a cell only contains one tile, it should be placed on the top layer, and the corresponding tile in the bottom layer should simply be floor. (Another way to think of this is that the floor byte, $00, represents nothing, but that every cell implicitly has floor underneath.)

Any tile may appear on either layer, which allows for a vast number of strange combinations. However, within the original rules of the game, the only valid combinations are a lone static tile, or a static tile with a movable object on top. Anything else (including some otherwise intuitive possibilities that would work in Chip's Challenge 2, like a key on gravel) is an invalid tile, will be rejected by Tile World's Lynx mode, and may behave unexpectedly.

A layer is a simple stream of bytes representing the tiles in reading order. A lone byte indicates a particular tile according to the encoding below. A $FF byte indicates simple run-length encoding, where the next two bytes are the number of copies and the byte to repeat. The sequence `00 FF 0A 01 00` thus describes twelve tiles: a floor tile, a span of ten walls, and another floor tile.

Tile encoding

The tile encoding exactly matches the arrangement of sprites in the MSCC tileset.

Values of $70 and above are used internally for graphical transparency.

	$0_	$1_	$2_	$3_	$4_	$5_	$6_
$_0	Floor	Clone block (S)	unused	Thin wall (SE)	Bug (N)	Glider (N)	Paramecium (N)
$_1	Wall	Clone block (E)	Thief	Cloner	Bug (W)	Glider (W)	Paramecium (W)
$_2	Computer chip	Force floor (N)	Chip socket	Random force floor	Bug (S)	Glider (S)	Paramecium (S)
$_3	Water	Force floor (E)	Green button	Drowned Chip	Bug (E)	Glider (E)	Paramecium (E)
$_4	Fire	Force floor (W)	Red button	Burned Chip	Fireball (N)	Teeth (N)	Blue key
$_5	Invisible wall	Exit	Toggle wall	Burned Chip	Fireball (W)	Teeth (W)	Red key
$_6	Thin wall (N)	Blue lock	Toggle floor	unused	Fireball (S)	Teeth (S)	Green key
$_7	Thin wall (W)	Red lock	Brown button	unused	Fireball (E)	Teeth (E)	Yellow key
$_8	Thin wall (S)	Green lock	Blue button	unused	Ball (N)	Walker (N)	Flippers
$_9	Thin wall (E)	Yellow lock	Teleporter	Fake exit	Ball (W)	Walker (W)	Fire boots
$_a	Dirt block	Ice corner (NW)	Bomb	Fake exit	Ball (S)	Walker (S)	Ice skates
$_b	Dirt	Ice corner (NE)	Trap	Fake exit	Ball (E)	Walker (E)	Suction boots
$_c	Ice	Ice corner (SE)	Hidden wall	Swimming Chip (N)	Tank (N)	Blob (N)	Chip (N)
$_d	Force floor (S)	Ice corner (SW)	Gravel	Swimming Chip (W)	Tank (W)	Blob (W)	Chip (W)
$_e	Clone block (N)	Fake blue wall	Recessed wall	Swimming Chip (S)	Tank (S)	Blob (S)	Chip (S)
$_f	Clone block (W)	Real blue wall	Hint	Swimming Chip (E)	Tank (E)	Blob (E)	Chip (E)

Level metadata chunks

Each chunk begins with a small header.

Because the length of a chunk is stored in a single byte, no chunk may be longer than 255 bytes.

Offset	Bytes	Content
$00	1	Chunk type
$01	1	Chunk length in bytes, not including this two-byte header

A level must have a title (3) and password (6). A level intended to work under MS rules should also have trap linkage (4), cloner linkage (5), and a monster list (10), or those elements will not work.

Unrecognized chunk types are ignored.

1: Time limit

Offset	Bytes	Content
$02	2	Time limit in seconds

This chunk is never used in the original game, since it's redundant with the time limit field in the level header.

2: Required chips

Offset	Bytes	Content
$02	2	Required number of chips

This chunk is never used in the original game, since it's redundant with the required chips field in the level header.

3: Title

Offset	Bytes	Content
$02	?	Map title. Must include a trailing NUL byte, and must not exceed 64 characters (including the NUL). Should generally be ASCII, though some programs interpret this as Latin-1 or Windows-1252.

4: Trap linkage

Contains zero or more of the following structure. As this structure is 10 bytes in size, the chunk size should be a multiple of 10, and there cannot be more than 25 trap linkages in a level. Any given brown button may only be linked to a single trap.

Offset	Bytes	Content
$00	2	x-coordinate of brown button
$02	2	y-coordinate of brown button
$04	2	x-coordinate of trap
$06	2	y-coordinate of trap
$08	2	Always zero. Presumably a placeholder for runtime state regarding whether the trap is open or closed.

This structure links brown buttons to traps in MSCC, where such linkage must be explicit. If a brown button is not listed in this chunk, it will not function in MSCC.

Tile World in Lynx mode will ignore this structure and always connect brown buttons in reading order.

If this chunk appears more than once, MSCC will only read the first, but Tile World will merge them all.

5: Cloner linkage

Contains zero or more of the following structure. As this structure is 8 bytes in size, the chunk size should be a multiple of 8, and there cannot be more than 31 cloner linkages in a level.

Offset	Bytes	Content
$00	2	x-coordinate of red button
$02	2	y-coordinate of red button
$04	2	x-coordinate of cloner
$06	2	y-coordinate of cloner

This structure links red buttons to cloners in MSCC, where such linkage must be explicit. If a red button is not listed in this chunk, it will not function in MSCC. Any given red button may only be linked to a single cloner.

Tile World in Lynx mode will ignore this structure and always connect red buttons in reading order.

If this chunk appears more than once, MSCC will only read the first, but Tile World will merge them all.

6: Password

Offset	Bytes	Content
$02	?	Encrypted password. Must include a trailing NUL. Should be ASCII. May be up to 10 characters, but generally should be 5 (4 + NUL).

The password is encrypted trivially, by XORing every character (not including the trailing NUL) with 0x99.

7: Hint

Offset	Bytes	Content
$02	?	Hint text. Must include a trailing NUL byte, and must not exceed 128 characters (including the NUL). Should generally be ASCII, though some programs interpret this as Latin-1 or Windows-1252.

8: Unencrypted password

This chunk is identical to chunk 6, but without the encryption. It is never used in the original CHIPS.DAT, and Tile World ignores it.

10: Monster list

Contains zero or more of the following structure. As this structure is 2 bytes in size, the chunk size should be a multiple of 2, and there cannot be more than 127 moving monsters in a level.

Offset	Bytes	Content
$00	1	x-coordinate of monster
$02	1	y-coordinate of monster

This structure allows monsters to move in MSCC; if a monster is not listed in this chunk, it will not move.

Tile World in Lynx mode will ignore this structure and always allow any number of monsters to move as normal.

9: Author

Offset	Bytes	Content
$02	?	Author's name. Must include a trailing NUL byte, and must not exceed 128 characters (including the NUL). Typically encoded as Windows-1252 or Latin-1.

This chunk is not present in the original game, and was later created as a community extension to include author info without relying on other files. This chunk is ignored by MSCC and early Tile World versions.

See also

• C2M, the more flexible format used in Chip's Challenge 2

External Links

• Explanation of the CHIPS.DAT format
• Implementation in Tile World: series.c (whole file) and encoding.c (individual level)
• Implementation in Lexy's Labyrinth: js/format-dat.js