Class: Cabriolet::LIT::PieceBuilder

Inherits:
Object
  • Object
show all
Defined in:
lib/cabriolet/lit/piece_builder.rb

Overview

Builds piece data for LIT files

Class Method Summary collapse

Class Method Details

.build_piece0(file_data) ⇒ String

Build piece 0 data (file size information)

Parameters:

  • file_data (Array<Hash>) —

    File data array

Returns:

  • (String) —

    Binary piece 0 data



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# File 'lib/cabriolet/lit/piece_builder.rb', line 13

def self.build_piece0(file_data)
  # Calculate total content size
  content_size = file_data.sum { |f| f[:uncompressed_size] }

  data = [Binary::LITStructures::Tags::SIZE_PIECE].pack("V")
  data += [content_size].pack("V")
  data += [0, 0].pack("VV") # High bits, reserved
  data
end

.build_piece1(directory) ⇒ String

Build piece 1 data (directory IFCM structure)

Parameters:

  • directory (Hash) —

    Directory structure from DirectoryBuilder

Returns:

  • (String) —

    Binary piece 1 data



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# File 'lib/cabriolet/lit/piece_builder.rb', line 27

def self.build_piece1(directory)
  builder = DirectoryBuilder.new(chunk_size: directory[:chunk_size])

  # Build IFCM header
  ifcm = Binary::LITStructures::IFCMHeader.new
  ifcm.tag = Binary::LITStructures::Tags::IFCM
  ifcm.version = 1
  ifcm.chunk_size = directory[:chunk_size]
  ifcm.param = 0x100000
  ifcm.reserved1 = 0xFFFFFFFF
  ifcm.reserved2 = 0xFFFFFFFF
  ifcm.num_chunks = directory[:num_chunks]
  ifcm.reserved3 = 0

  data = ifcm.to_binary_s

  # Build AOLL chunk with directory entries
  directory[:entries].each do |entry|
    builder.add_entry(
      name: entry[:name],
      section: entry[:section],
      offset: entry[:offset],
      size: entry[:size],
    )
  end

  aoll_chunk = builder.build_aoll_chunk
  data += aoll_chunk

  # Pad to fill piece (8KB standard)
  target_size = 8192
  if data.bytesize < target_size
    data += "\x00" * (target_size - data.bytesize)
  end

  data
end

.build_piece2 ⇒ String

Build piece 2 data (index information)

Returns:

  • (String) —

    Binary piece 2 data



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# File 'lib/cabriolet/lit/piece_builder.rb', line 68

def self.build_piece2
  # Minimal index data for foundation
  "\x00" * 512
end