module HexaPDF::Filter::FlateDecode
Implements the Deflate filter using the Zlib library.
See: HexaPDF::Filter
, PDF1.7 s7.4.4
Public Class Methods
decoder(source, options = nil)
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See HexaPDF::Filter
The decoder also handles the case of an empty string not deflated to a correct flate stream but just output as an empty string.
# File lib/hexapdf/filter/flate_decode.rb, line 54 def self.decoder(source, options = nil) fib = Fiber.new do inflater = Zlib::Inflate.new while source.alive? && (data = source.resume) next if data.empty? begin data = inflater.inflate(data) rescue StandardError => e raise FilterError, "Problem while decoding Flate encoded stream: #{e}" end Fiber.yield(data) end begin data = inflater.total_in == 0 || (data = inflater.finish).empty? ? nil : data inflater.close data rescue StandardError => e raise FilterError, "Problem while decoding Flate encoded stream: #{e}" end end if options && options[:Predictor] Predictor.decoder(fib, options) else fib end end
encoder(source, options = nil)
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See HexaPDF::Filter
# File lib/hexapdf/filter/flate_decode.rb, line 83 def self.encoder(source, options = nil) if options && options[:Predictor] source = Predictor.encoder(source, options) end Fiber.new do deflater = Zlib::Deflate.new(HexaPDF::GlobalConfiguration['filter.flate_compression'], Zlib::MAX_WBITS, HexaPDF::GlobalConfiguration['filter.flate_memory']) while source.alive? && (data = source.resume) data = deflater.deflate(data) Fiber.yield(data) end data = deflater.finish deflater.close data end end