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# =GZip Simple
#
# A simplified interface to the gzip library +zlib+ (from the Ruby Standard Library.)
#
# Author: murphy (mail to murphy cYcnus 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
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