SCUMM/Technical Reference/Index File

SCUMM Technical Reference → SCUMM index file

Introduction

Most of the information below are retrieved from the LucasHacks! site and from the Pascal source code of the IndexFileReader 1.2 (written by Ben Gorman (Bgbennyboy, http://quick.mixnmojo.com). In addition, ScummRevisited (written by Jimmi Thøgersen (Serge), http://www.mixnmojo.com/scumm/scummrev) turned out to be very useful in verifying the found offsets.

The SCUMM index file contains special information to allow quick random access to the resources in the other game files. It also includes the room names and some max limits for the game. The following filenames are used:

filename	SCUMM version
00.lfl / 000.lfl	V3/4
.000	V5/6
.LA0	V7/8

Version 1 to 3 use hardcoded offsets and cannot be treated that easily. For the other games, the index file can be used to determine the SCUMM version because there have been slight changes in each version.

• Version 4: the 5th and 6th byte match RN or OR
• Version 5: RNAM xor'ed with 0x69 at the beginning of the file, next 4 byte integer xor'ed with 0x69 is > 9
• Version 6: RNAM xor'ed with 0x69 at the beginning, next 4 byte integer xor'ed with 0x69 is 9 (actually it's the size of the chunk. In V6 games, no room names are stored so the size is 4 bytes (header) + 4 bytes (size) + 1 byte for the termination character).
• Version 7: RNAM at the beginning of the file (not xor'ed this time), next 4 bytes result in BE integer 9. (NOTE: must be verified!)
• Version 8: RNAM at the beginning of the file, next 4 bytes integer is > 9

Conventions

As usual, the endianness (Wikipedia) is important. Unless stated, little endianess (LE) is used. BE is used as abbreviation for big endianness.

A Chunk is a named part of the file, e.g. RNAM. Each chunk has a header that contains at least the chunk name and its size. The following chunks are available:

RNAM Room Names	In V5+
MAXS Maximum Values	In V5+
DROO Directory of Rooms	In V5+
DRSC Direcory of Room Scripts	In V8
DSCR Directory of Scripts	In V5+
DSOU Directory of Sounds	In V5+
DCOS Directory of Costumes	In V5+
DCHR Directory of Charsets	In V5+
DOBJ Directory of Objects	In V5+
AARY List of Arrays	In V6+
ANAM Animation Names?	In V7
RM Room Names	In V3/4
0R Directory Of Rooms	In V3/4
0S Directory Of Scripts?	In V3/4
0N Directory Of Sounds?	In V3/4
0C Directory Of Costumes?	In V3/4
0O Directory Of Objects?	In V3/4

Scumm 3/4

• File's aren't xor'ed
• Block Size does not include the 6 bytes used up by Block Name and Block Size, it's the size of the data that follows.

RN

Block Size         (4 bytes)
Block Name         (2 bytes)
  #Room No         (1 byte)
  #Room Name       (9 bytes) XOR'ed with FF
Blank (00) byte    (1 byte) Marks end of chunk

0R

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Room Number     (1 byte)
  *Offset          (4 bytes)

0S

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Room Number     (1 byte)
  *Offset          (4 bytes)

0N

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Room Number     (1 byte)
  *Offset          (4 bytes)

0C

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Room Number     (1 byte)
  *Offset          (4 bytes)

0O

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Owner of Object (1 byte)

Scumm 5

tbd.

Scumm 6

tbd.

Scumm 7

tbd.

Scumm 8

tbd.