Class: PDF::Reader::Filter

Inherits:
Object
  • Object
show all
Defined in:
lib/pdf/reader/filter.rb

Overview

Various parts of a PDF file can be passed through a filter before being stored to provide support for features like compression and encryption. This class is for decoding that content.

Currently only 1 filter type is supported. Hopefully support for others will be added in the future.

Instance Method Summary collapse

Constructor Details

#initialize(name, options) ⇒ Filter

creates a new filter for decoding content



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# File 'lib/pdf/reader/filter.rb', line 38

def initialize (name, options)
  @options = options

  case name
  when "FlateDecode"    then @filter = :flate
  else                    raise UnsupportedFeatureError, "Unknown filter: #{name}"
  end
end

Instance Method Details

#filter(data) ⇒ Object

attempts to decode the specified data with the current filter



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# File 'lib/pdf/reader/filter.rb', line 48

def filter (data)
  self.send(@filter, data)
end

#flate(data) ⇒ Object

Decode the specified data with the Zlib compression algorithm



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# File 'lib/pdf/reader/filter.rb', line 53

def flate (data)
  z = Zlib::Inflate.new
  z << data
  z.inflate(nil)
end