lib/zip/inflater.rb
module Zip
class Inflater < Decompressor #:nodoc:all
def initialize(input_stream)
super
@zlib_inflater = ::Zlib::Inflate.new(-Zlib::MAX_WBITS)
@output_buffer = ''
@has_returned_empty_string = false
end
def sysread(number_of_bytes = nil, buf = '')
readEverything = number_of_bytes.nil?
while readEverything || @output_buffer.bytesize < number_of_bytes
break if internal_input_finished?
@output_buffer << internal_produce_input(buf)
end
return value_when_finished if @output_buffer.bytesize == 0 && input_finished?
end_index = number_of_bytes.nil? ? @output_buffer.bytesize : number_of_bytes
@output_buffer.slice!(0...end_index)
end
def produce_input
if (@output_buffer.empty?)
internal_produce_input
else
@output_buffer.slice!(0...(@output_buffer.length))
end
end
# to be used with produce_input, not read (as read may still have more data cached)
# is data cached anywhere other than @outputBuffer? the comment above may be wrong
def input_finished?
@output_buffer.empty? && internal_input_finished?
end
alias :eof :input_finished?
alias :eof? :input_finished?
private
def internal_produce_input(buf = '')
retried = 0
begin
@zlib_inflater.inflate(@input_stream.read(Decompressor::CHUNK_SIZE, buf))
rescue Zlib::BufError
raise if retried >= 5 # how many times should we retry?
retried += 1
retry
end
end
def internal_input_finished?
@zlib_inflater.finished?
end
def value_when_finished # mimic behaviour of ruby File object.
return if @has_returned_empty_string
@has_returned_empty_string = true
''
end
end
end
# Copyright (C) 2002, 2003 Thomas Sondergaard
# rubyzip is free software; you can redistribute it and/or
# modify it under the terms of the ruby license.