88 lines
2.2 KiB
Ruby
88 lines
2.2 KiB
Ruby
require 'bindata/single'
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module BinData
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# Provides a number of classes that contain a floating point number.
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# The float is defined by endian, and precision.
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module Float #:nodoc: all
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def self.create_float_methods(klass, single_precision, endian)
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read = create_read_code(single_precision, endian)
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to_s = create_to_s_code(single_precision, endian)
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define_methods(klass, single_precision, read, to_s)
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end
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def self.create_read_code(single_precision, endian)
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if single_precision
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unpack = (endian == :little) ? 'e' : 'g'
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nbytes = 4
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else # double_precision
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unpack = (endian == :little) ? 'E' : 'G'
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nbytes = 8
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end
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"io.readbytes(#{nbytes}).unpack('#{unpack}').at(0)"
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end
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def self.create_to_s_code(single_precision, endian)
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if single_precision
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pack = (endian == :little) ? 'e' : 'g'
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else # double_precision
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pack = (endian == :little) ? 'E' : 'G'
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end
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"[val].pack('#{pack}')"
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end
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def self.define_methods(klass, single_precision, read, to_s)
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nbytes = single_precision ? 4 : 8
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# define methods in the given class
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klass.module_eval <<-END
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def _do_num_bytes(ignored)
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#{nbytes}
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end
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#---------------
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private
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def sensible_default
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0.0
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end
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def val_to_str(val)
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#{to_s}
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end
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def read_val(io)
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#{read}
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end
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END
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end
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end
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# Single precision floating point number in little endian format
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class FloatLe < BinData::Single
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register(self.name, self)
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Float.create_float_methods(self, true, :little)
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end
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# Single precision floating point number in big endian format
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class FloatBe < BinData::Single
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register(self.name, self)
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Float.create_float_methods(self, true, :big)
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end
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# Double precision floating point number in little endian format
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class DoubleLe < BinData::Single
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register(self.name, self)
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Float.create_float_methods(self, false, :little)
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end
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# Double precision floating point number in big endian format
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class DoubleBe < BinData::Single
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register(self.name, self)
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Float.create_float_methods(self, false, :big)
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end
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end |