The Valve Binary Space Partition file format in Kaitai Struct.

valve_binary_space_partition_format.ksy

meta:
  id: vbsp
  title: "Valve Binary Space Partition"
  tags: [ "vbsp", "bsp", "source", "valve" ]
  file-extension: bsp
  endian: le

doc: |
  Valve Binary Space Partition, or VBSP, is a file format for levels; it is a variant of the Binary Space Partition level format used by Quake.

  VBSP are primarily created through the `vbsp` executable, made by Valve that is packaged in the Source Engine.

  **TODO: Handle LZMA data.**
  
doc-ref: https://developer.valvesoftware.com/wiki/VBSP

seq:
  - id: signature
    contents: "VBSP"
    doc: "The format signature to identify VBSP files."
    
  - id: version
    type: u4
    doc: |
      File format version.
  - id: lump_header_array
    type: lump_header
    repeat: expr
    repeat-expr: 64
    doc: |
      64-dimension array of lump metadata.

  - id: map_revision_number
    type: u4
    doc: |
      An integer that stores the map's iteration and version.
      
types:
  lump_header:
    seq:
      - id: file_offset
        type: u4
        doc: |
          Location of the data lump.
          
      - id: byte_length
        type: u4
        doc: |
          Byte length of the data lump.

      - id: version
        type: u4
        doc: |
          Format version of the data lump.

      - id: identifier
        size: 4
        doc: |
          4th-dimensional byte array to identify the data lump.
          
    instances:
      lump:
        pos: file_offset
        size: byte_length
        doc: The data stored by the lump.

# SUGGESTION: Should I add preset lump types.