File format basics

The .LFL and .LEC files are made-up of chunks. Every chunk consists of three parts: length, type and value. The file format structure is similar to the TLV and IFF standards.

┌────────────────────────────────┬────────────────┬────────────────~──┐
│            length              │      type      │       value       │
│           (32 bit)             │    (2 byte)    │ (variable length) │
└────────────────────────────────┴────────────────┴────────────────~──┘

• The length is a 32-bit number and contains the length of the entire chunk (including the length field itself).
• The type are 2 bytes of ASCII characters.
• The value is a variable structure based on the chunk type. It could also contain another chunk (tree structure).

The byte order of multibyte numbers (like chunk length) is little-endian if not otherwise specified. For example a 32-bit number 0x01234567 would be stored on disk as 0x67 0x45 0x23 0x01, a value of decimal 10 would be stored as 0x0A 0x00 0x00 0x00 (when using 32-bit).

Watch out for these inconsistencies:

• The length field sometimes is simply wrong
• The type field sometimes is ambiguous
• Some files are (partially) encrypted

The documentation about the specific file types contains more details about this.