124 lines
2.6 KiB
Ruby
124 lines
2.6 KiB
Ruby
# =GZip Simple
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#
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# A simplified interface to the gzip library +zlib+ (from the Ruby Standard Library.)
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#
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# Author: murphy (mail to murphy cYcnus de)
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#
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# Version: 0.2 (2005.may.28)
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#
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# ==Documentation
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#
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# See +GZip+ module and the +String+ extensions.
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#
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module GZip
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require 'zlib'
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# The default zipping level. 7 zips good and fast.
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DEFAULT_GZIP_LEVEL = 7
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# Unzips the given string +s+.
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#
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# Example:
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# require 'gzip_simple'
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# print GZip.gunzip(File.read('adresses.gz'))
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def GZip.gunzip s
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Zlib::Inflate.inflate s
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end
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# Zips the given string +s+.
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#
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# Example:
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# require 'gzip_simple'
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# File.open('adresses.gz', 'w') do |file
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# file.write GZip.gzip('Mum: 0123 456 789', 9)
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# end
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#
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# If you provide a +level+, you can control how strong
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# the string is compressed:
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# - 0: no compression, only convert to gzip format
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# - 1: compress fast
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# - 7: compress more, but still fast (default)
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# - 8: compress more, slower
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# - 9: compress best, very slow
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def GZip.gzip s, level = DEFAULT_GZIP_LEVEL
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Zlib::Deflate.new(level).deflate s, Zlib::FINISH
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end
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end
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# String extensions to use the GZip module.
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#
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# The methods gzip and gunzip provide an even more simple
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# interface to the ZLib:
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#
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# # create a big string
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# x = 'a' * 1000
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#
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# # zip it
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# x_gz = x.gzip
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#
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# # test the result
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# puts 'Zipped %d bytes to %d bytes.' % [x.size, x_gz.size]
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# #-> Zipped 1000 bytes to 19 bytes.
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#
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# # unzipping works
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# p x_gz.gunzip == x #-> true
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class String
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# Returns the string, unzipped.
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# See GZip.gunzip
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def gunzip
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GZip.gunzip self
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end
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# Replaces the string with its unzipped value.
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# See GZip.gunzip
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def gunzip!
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replace gunzip
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end
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# Returns the string, zipped.
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# +level+ is the gzip compression level, see GZip.gzip.
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def gzip level = GZip::DEFAULT_GZIP_LEVEL
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GZip.gzip self, level
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end
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# Replaces the string with its zipped value.
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# See GZip.gzip.
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def gzip!(*args)
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replace gzip(*args)
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end
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end
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if $0 == __FILE__
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eval DATA.read, nil, $0, __LINE__+4
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end
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__END__
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#CODE
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# Testing / Benchmark
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x = 'a' * 1000
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x_gz = x.gzip
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puts 'Zipped %d bytes to %d bytes.' % [x.size, x_gz.size] #-> Zipped 1000 bytes to 19 bytes.
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p x_gz.gunzip == x #-> true
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require 'benchmark'
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INFO = 'packed to %0.3f%%' # :nodoc:
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x = Array.new(100000) { rand(255).chr + 'aaaaaaaaa' + rand(255).chr }.join
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Benchmark.bm(10) do |bm|
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for level in 0..9
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bm.report "zip #{level}" do
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$x = x.gzip level
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end
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puts INFO % [100.0 * $x.size / x.size]
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end
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bm.report 'zip' do
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$x = x.gzip
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end
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puts INFO % [100.0 * $x.size / x.size]
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bm.report 'unzip' do
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$x.gunzip
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end
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end
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