Class: Mix1::Reader

Inherits:
Object
  • Object
show all
Defined in:
lib/mix1.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file_path:, ignore_crc_mismatches: false, metadata_only: false, buffer_size: DEFAULT_BUFFER_SIZE) ⇒ Reader

Returns a new instance of Reader.



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# File 'lib/mix1.rb', line 201

def initialize(file_path:, ignore_crc_mismatches: false, metadata_only: false, buffer_size: DEFAULT_BUFFER_SIZE)
  @package = Package.new

  @buffer = MemoryBuffer.new(file_path: file_path, mode: :read, buffer_size: buffer_size)

  @buffer.pos = 0

  # Valid header
  if read_i32 == 0x3158494D
    file_data_offset = read_i32
    file_names_offset = read_i32

    @buffer.pos = file_names_offset
    file_count = read_i32

    file_count.times do
      @package.files << Package::File.new(name: read_string)
    end

    @buffer.pos = file_data_offset
    @buffer.cache_file_data_chunk!

    _file_count = read_i32

    file_count.times do |i|
      file = @package.files[i]

      file.mix_crc = read_u32.to_s(16).rjust(8, "0")
      file.content_offset = read_u32
      file.content_length = read_u32

      if !ignore_crc_mismatches && file.mix_crc != file.file_crc
        raise MixParserException, "CRC mismatch for #{file.name}. #{file.mix_crc.inspect} != #{file.file_crc.inspect}"
      end

      pos = @buffer.pos
      @buffer.pos = file.content_offset
      file.data = @buffer.read(file.content_length) unless metadata_only
      @buffer.pos = pos
    end
  else
    raise MixParserException, "Invalid MIX file"
  end
ensure
  @buffer&.close
  @buffer = nil # let GC collect
end

Instance Attribute Details

#package ⇒ Object (readonly)

Returns the value of attribute package.



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# File 'lib/mix1.rb', line 199

def package
  @package
end

Instance Method Details

#read_i32 ⇒ Object 



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# File 'lib/mix1.rb', line 249

def read_i32
  @buffer.read(4).unpack1("l")
end

#read_string ⇒ Object 



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# File 'lib/mix1.rb', line 257

def read_string
  buffer = ""

  length = @buffer.readbyte

  length.times do
    buffer << @buffer.readbyte
  end

  buffer.strip
end

#read_u32 ⇒ Object 



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# File 'lib/mix1.rb', line 253

def read_u32
  @buffer.read(4).unpack1("L")
end