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module Packable
module Extensions #:nodoc:
module Integer #:nodoc:
NEEDS_REVERSAL = Hash.new{|h, endian| raise ArgumentError, "Endian #{endian} is not valid. It must be one of #{h.keys.join(', ')}"}.
merge!(:little => true, :big => false, :network => false, :native => "*\x00\x00\x00".unpack('L').first == 42).freeze
def self.included(base)
base.class_eval do
include Packable
extend ClassMethods
packers do |p|
p.set :merge_all , :bytes=>4, :signed=>true, :endian=>:big
p.set :default , :long
p.set :long , {}
p.set :short , :bytes=>2
p.set :char , :bytes=>1, :signed=>false
p.set :byte , :bytes=>1
p.set :unsigned_long , :bytes=>4, :signed=>false
p.set :unsigned_short , :bytes=>2, :signed=>false
end
end
end
def write_packed(io, options)
val = self
chars = (0...options[:bytes]).collect do
byte = val & 0xFF
val >>= 8
byte.chr
end
chars.reverse! unless NEEDS_REVERSAL[options[:endian]]
io << chars.join
end
module ClassMethods #:nodoc:
def unpack_string(s,options)
s = s.reverse if NEEDS_REVERSAL[options[:endian]]
r = 0
s.each_byte {|b| r = (r << 8) + b}
r -= 1 << (8 * options[:bytes]) if options[:signed] && (1 == r >> (8 * options[:bytes] - 1))
r
end
end
end
end
end
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