LMS File Format

LMS > File Format Overview

This page describes the general structure of files loaded by the LMS library. The files start with a header which is followed by different kinds of blocks. All blocks are aligned to 16 bytes. The space between two blocks is padded with 0xAB bytes.

The following file formats are used by LMS:

• MSBT files (messages)
• MSBP files (projects)
• MSBF files (flow charts)

File Header

Offset	Size	Description
0x0	8	Magic number
0x8	2	Endianness (0xFEFF=Big, 0xFFFE=Little)
0xA	2	Unknown (always 0?)
0xC	1	Message encoding (0=UTF-8, 1=UTF-16, 2=UTF-32)
0xD	1	Version number (always 3)
0xE	2	Number of blocks
0x10	2	Unknown (always 0?)
0x12	4	Filesize
0x16	10	Padding

Block Header

Offset	Size	Description
0x0	4	Block type
0x4	4	Block size (without header)
0x8	8	Padding
0x10		Block data

Hash Tables

Many items (such as messages in msbt files or colors in msbp files) are looked up by label. The labels are looked up with a hash table and are stored in a different block than the items themselves. In official files the hash table always has a fixed number of slots (101 in msbt files, 29 in msbp files), even if it contains only a few labels.

The following hash algorithm is used:

def calc_hash(label, num_slots):
    hash = 0
    for char in label:
        hash = hash * 0x492 + ord(char)
    return (hash & 0xFFFFFFFF) % num_slots

The block with the labels contains the following data:

Offset	Size	Description
0x0	4	Number of slots
0x4	8 per slot	Hash table slots
	Labels

Hash Table Slot

Offset	Size	Description
0x0	4	Number of labels
0x4	4	Offset to labels

Label

Offset	Size	Description
0x0	1	Length of label string
0x1		Label string (without null terminator)
	4	Item index