Class: IFF::Parser

Inherits:
Object
  • Object
show all
Includes:
ParserEmitterCommon
Defined in:
lib/iff.rb

Instance Method Summary collapse

Methods included from ParserEmitterCommon

#padding_required_for?

Constructor Details

#initialize(stream, length = nil, options = {}) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/iff.rb', line 128

def initialize( stream, length=nil, options={} )
  super( stream, options )
  @length = length
end

Instance Method Details

#parse ⇒ Object

Raises:

  • (EOFError) 


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# File 'lib/iff.rb', line 133

def parse
  if @length
    return nil if @length.zero?
    raise EOFError, "Premature end of IFF header" \
      if @length < HEADER_LENGTH
  end

  header = @stream.read( HEADER_LENGTH )
  unless header
    if @length && @length.nonzero?
      raise EOFError, "More chunks expected"
    else
      return nil
    end
  end

  raise EOFError, "Premature end of IFF header" \
    if header.length < HEADER_LENGTH

  ( tag, length ) = header.unpack( @header_format )

  raise EOFError, "Body too short" \
    if @length && @length < length

  factory = IFF.get_type( tag )
  if !factory && @options[:skip_unknown]
    length += 1 if padding_required_for? length
    skip_bytes( length )
    retry
  end
  factory ||= Chunk
  
  chunk = factory.unserialize( tag, length, @stream, @options )
  @length -= length if @length
  skip_bytes( 1 ) if padding_required_for? length
  chunk
end