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module Packable
module Extensions #:nodoc:
module Float #:nodoc:
def self.included(base)
base.class_eval do
include Packable
extend ClassMethods
packers do |p|
p.set :merge_all, :precision => :single, :endian => :big
p.set :double , :precision => :double
p.set :float , {}
p.set :default , :float
end
end
end
def write_packed(io, options)
io << pack(self.class.pack_option_to_format(options))
end
module ClassMethods #:nodoc:
ENDIAN_TO_FORMAT = Hash.new{|h, endian| raise ArgumentError, "Endian #{endian} is not valid. It must be one of #{h.keys.join(', ')}."}.
merge!(:big => "G", :network => "G", :little => "E", :native => "D").freeze
FORMAT_TO_SINGLE_PRECISION = {'G' => 'g', 'E' => 'e', 'D' => 'f'}.freeze
PRECISION = Hash.new{|h, precision| raise ArgumentError, "Precision #{precision} is not valid. It must be one of #{h.keys.join(', ')}."}.
merge!(:single => 4, :double => 8).freeze
def pack_option_to_format(options)
format = ENDIAN_TO_FORMAT[options[:endian]]
format = FORMAT_TO_SINGLE_PRECISION[format] if options[:precision] == :single
format
end
def read_packed(io, options)
s = io.read_exactly(PRECISION[options[:precision]])
s && s.unpack(pack_option_to_format(options)).first
end
end
end
end
end
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