Class: Cabriolet::LIT::Compressor

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

Overview

Compressor creates LIT eBook files

LIT files are Microsoft Reader eBook files that use LZX compression. The compressor allows adding multiple files to create a LIT archive.

NOTE: This implementation creates non-encrypted LIT files only. DES encryption (DRM protection) is not implemented.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(io_system = nil, algorithm_factory = nil) ⇒ Compressor

Initialize a new LIT compressor

Parameters:

  • io_system (System::IOSystem, nil) (defaults to: nil) —

    Custom I/O system or nil for default

  • algorithm_factory (AlgorithmFactory, nil) (defaults to: nil) —

    Custom algorithm factory or nil for default



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

def initialize(io_system = nil, algorithm_factory = nil)
  @io_system = io_system || System::IOSystem.new
  @algorithm_factory = algorithm_factory || Cabriolet.algorithm_factory
  @files = []
end

Instance Attribute Details

#files ⇒ Object (readonly)

Returns the value of attribute files.



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# File 'lib/cabriolet/lit/compressor.rb', line 21

def files
  @files
end

#io_system ⇒ Object (readonly)

Returns the value of attribute io_system.



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# File 'lib/cabriolet/lit/compressor.rb', line 21

def io_system
  @io_system
end

Instance Method Details

#add_file(source_path, lit_path, **options) ⇒ void

This method returns an undefined value.

Add a file to the LIT archive

Parameters:

  • source_path (String) —

    Path to the source file

  • lit_path (String) —

    Path within the LIT archive

  • options (Hash) —

    Options for the file

Options Hash (**options):

  • :compress (Boolean) —

    Whether to compress the file (default: true)



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# File 'lib/cabriolet/lit/compressor.rb', line 40

def add_file(source_path, lit_path, **options)
  compress = options.fetch(:compress, true)

  @files << {
    source: source_path,
    lit_path: lit_path,
    compress: compress,
  }
end

#generate(output_file, **options) ⇒ Integer

Generate the LIT archive

Parameters:

  • output_file (String) —

    Path to output LIT file

  • options (Hash) —

    Generation options

Options Hash (**options):

  • :version (Integer) —

    LIT format version (default: 1)

  • :language_id (Integer) —

    Language ID (default: 0x409 English)

  • :creator_id (Integer) —

    Creator ID (default: 0)

Returns:

  • (Integer) —

    Bytes written to output file

Raises:

  • (Errors::CompressionError) —

    if compression fails



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

def generate(output_file, **options)
  version = options.fetch(:version, 1)
  language_id = options.fetch(:language_id, 0x409)
  creator_id = options.fetch(:creator_id, 0)

  raise ArgumentError, "No files added to archive" if @files.empty?
  raise ArgumentError, "Version must be 1" unless version == 1

  # Prepare file data
  file_data = prepare_files

  # Build LIT structure
  structure_builder = StructureBuilder.new(
    io_system: @io_system,
    version: version,
    language_id: language_id,
    creator_id: creator_id,
  )
  lit_structure = structure_builder.build(file_data)

  # Write to output file
  output_handle = @io_system.open(output_file, Constants::MODE_WRITE)
  begin
    bytes_written = write_lit_file(output_handle, lit_structure)
    bytes_written
  ensure
    @io_system.close(output_handle)
  end
end