Class: Cabriolet::LIT::HeaderWriter

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

Overview

Writes LIT headers to output

Instance Method Summary collapse

Constructor Details

#initialize(io_system) ⇒ HeaderWriter

Initialize header writer

Parameters:



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# File 'lib/cabriolet/lit/header_writer.rb', line 10

def initialize(io_system)
  @io_system = io_system
end

Instance Method Details

#write_piece_structures(output_handle, pieces) ⇒ Integer

Write piece structures

Parameters:

  • output_handle (System::FileHandle) —

    Output file handle

  • pieces (Array<Hash>) —

    Pieces array

Returns:

  • (Integer) —

    Bytes written



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# File 'lib/cabriolet/lit/header_writer.rb', line 37

def write_piece_structures(output_handle, pieces)
  total_bytes = 0

  pieces.each do |piece|
    piece_struct = Binary::LITStructures::PieceStructure.new
    piece_struct.offset_low = piece[:offset]
    piece_struct.offset_high = 0
    piece_struct.size_low = piece[:size]
    piece_struct.size_high = 0

    piece_data = piece_struct.to_binary_s
    total_bytes += @io_system.write(output_handle, piece_data)
  end

  total_bytes
end

#write_primary_header(output_handle, structure) ⇒ Integer

Write primary header

Parameters:

  • output_handle (System::FileHandle) —

    Output file handle

  • structure (Hash) —

    LIT structure

Returns:

  • (Integer) —

    Bytes written



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# File 'lib/cabriolet/lit/header_writer.rb', line 19

def write_primary_header(output_handle, structure)
  header = Binary::LITStructures::PrimaryHeader.new
  header.signature = Binary::LITStructures::SIGNATURE
  header.version = structure[:version]
  header.header_length = 40
  header.num_pieces = 5
  header.secondary_header_length = structure[:secondary_header][:length]
  header.header_guid = structure[:header_guid]

  header_data = header.to_binary_s
  @io_system.write(output_handle, header_data)
end

#write_secondary_header(output_handle, sec_hdr) ⇒ Integer

Write secondary header block

Parameters:

  • output_handle (System::FileHandle) —

    Output file handle

  • sec_hdr (Hash) —

    Secondary header metadata

Returns:

  • (Integer) —

    Bytes written



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# File 'lib/cabriolet/lit/header_writer.rb', line 59

def write_secondary_header(output_handle, sec_hdr)
  header = Binary::LITStructures::SecondaryHeader.new

  # SECHDR block
  header.sechdr_version = 2
  header.sechdr_length = 152

  # Entry directory info
  header.entry_aoli_idx = 0
  header.entry_aoli_idx_high = 0
  header.entry_reserved1 = 0
  header.entry_last_aoll = 0
  header.entry_reserved2 = 0
  header.entry_chunklen = sec_hdr[:entry_chunklen]
  header.entry_two = 2
  header.entry_reserved3 = 0
  header.entry_depth = sec_hdr[:entry_depth]
  header.entry_reserved4 = 0
  header.entry_entries = sec_hdr[:entry_entries]
  header.entry_reserved5 = 0

  # Count directory info
  header.count_aoli_idx = 0xFFFFFFFF
  header.count_aoli_idx_high = 0xFFFFFFFF
  header.count_reserved1 = 0
  header.count_last_aoll = 0
  header.count_reserved2 = 0
  header.count_chunklen = sec_hdr[:count_chunklen]
  header.count_two = 2
  header.count_reserved3 = 0
  header.count_depth = 1
  header.count_reserved4 = 0
  header.count_entries = sec_hdr[:count_entries]
  header.count_reserved5 = 0

  header.entry_unknown = sec_hdr[:entry_unknown]
  header.count_unknown = sec_hdr[:count_unknown]

  # CAOL block
  header.caol_tag = Binary::LITStructures::Tags::CAOL
  header.caol_version = 2
  header.caol_length = 80 # 48 + 32
  header.creator_id = sec_hdr[:creator_id]
  header.caol_reserved1 = 0
  header.caol_entry_chunklen = sec_hdr[:entry_chunklen]
  header.caol_count_chunklen = sec_hdr[:count_chunklen]
  header.caol_entry_unknown = sec_hdr[:entry_unknown]
  header.caol_count_unknown = sec_hdr[:count_unknown]
  header.caol_reserved2 = 0

  # ITSF block
  header.itsf_tag = Binary::LITStructures::Tags::ITSF
  header.itsf_version = 4
  header.itsf_length = 32
  header.itsf_unknown = 1
  header.content_offset_low = sec_hdr[:content_offset]
  header.content_offset_high = 0
  header.timestamp = sec_hdr[:timestamp]
  header.language_id = sec_hdr[:language_id]

  header_data = header.to_binary_s
  @io_system.write(output_handle, header_data)
end