Class: IOP::ZlibDecompressor

Inherits:
Object
  • Object
show all
Includes:
Feed, Sink
Defined in:
lib/iop/zlib.rb

Overview

Filter class to perform data decompression with Zlib algorithm.

This class is an adapter for the standard Ruby Zlib::Inflate class.

Note that this class can not decompress .gz files - use GzipDecompressor for this purpose.

### Use case: decompress a Zlib-compressed part of a file skipping a header and compute MD5 hash sum of the uncompressed data.

require 'iop/zlib'
require 'iop/file'
require 'iop/digest'
( IOP::FileReader.new('input.dat', offset: 16) | IOP::ZlibDecompressor.new | (d = IOP::DigestComputer.new(Digest::MD5.new)) ).process!
puts d.digest.hexdigest

Since:

  • 0.1

Direct Known Subclasses

GzipDecompressor

Instance Attribute Summary

Attributes included from Sink

#upstream

Attributes included from Feed

#downstream

Instance Method Summary collapse

Methods included from Feed

#|

Constructor Details

#initialize(*args) ⇒ ZlibDecompressor

Creates class instance.

Parameters:

  • args (Array) —

    arguments passed to Zlib::Inflate constructor

Since:

  • 0.1



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# File 'lib/iop/zlib.rb', line 81

def initialize(*args)
  @args = args
end

Instance Method Details

#process(data = nil) ⇒ Object

Since:

  • 0.1



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# File 'lib/iop/zlib.rb', line 85

def process(data = nil)
  if data.nil?
    super(@inflate.finish)
    super
  else
    super(@inflate.inflate(data))
  end
end

#process! ⇒ Object

Since:

  • 0.1



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# File 'lib/iop/zlib.rb', line 94

def process!
  @inflate = Zlib::Inflate.new(*@args)
  begin
    super
  ensure
    @inflate.close
  end
end