comparison vendor/gems/coderay-0.9.7/lib/coderay/helpers/gzip_simple.rb @ 523:0b6c82dead28 luisf

Merge from branch "cannam"

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