Module: Pdfrb::Source::ObjectStreamReader

Defined in:
lib/pdfrb/source/object_stream_reader.rb

Overview

Object streams (s7.5.7). Decodes the /Type /ObjStm stream and yields (oid, value) pairs.

Class Method Summary collapse

Class Method Details

.read(stream_object, document) ⇒ Object

Returns an Array of (oid, value) pairs in declaration order.

Raises:



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# File 'lib/pdfrb/source/object_stream_reader.rb', line 11

def read(stream_object, document)
  decoded = stream_object.decoded_stream
  dict = stream_object
  n = dict[:N]
  first = dict[:First] || 0
  raise Pdfrb::ParseError, "ObjStm missing /N or /First" if n.nil? || first.nil?

  # Header: N pairs of "oid offset" separated by whitespace.
  header = decoded.byteslice(0, first)
  pairs = header.split(/\s+/).each_slice(2).to_a
  raise Pdfrb::ParseError, "ObjStm header mismatch" unless pairs.length == n

  body_io = StringIO.new(decoded.byteslice(first..).to_s.b)
  tokenizer = Tokenizer.new(body_io)
  parser = Parser.new(tokenizer, document: document)
  pairs.each_with_index.map do |(oid_s, _off_s), _i|
    [oid_s.to_i, parser.parse_value]
  end
end