class PDF::Reader::Filter::Flate
implementation of the Flate
(zlib) stream filter
Constants
- ZLIB_AUTO_DETECT_ZLIB_OR_GZIP
Public Class Methods
new(options = {})
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# File lib/pdf/reader/filter/flate.rb, line 13 def initialize(options = {}) @options = options end
Public Instance Methods
filter(data)
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Decode the specified data with the Zlib compression algorithm
# File lib/pdf/reader/filter/flate.rb, line 19 def filter(data) deflated = nil begin deflated = Zlib::Inflate.new(ZLIB_AUTO_DETECT_ZLIB_OR_GZIP).inflate(data) rescue Zlib::DataError => e # by default, Ruby's Zlib assumes the data it's inflating # is RFC1951 deflated data, wrapped in a RFC1950 zlib container. If that # fails, then use a lightly-documented 'feature' to attempt to inflate # the data as a raw RFC1951 stream. # # See # - http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/243545 deflated = Zlib::Inflate.new(-Zlib::MAX_WBITS).inflate(data) end Depredict.new(@options).filter(deflated) rescue Exception => e # Oops, there was a problem inflating the stream raise MalformedPDFError, "Error occured while inflating a compressed stream (#{e.class.to_s}: #{e.to_s})" end