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require 'bindata/base_primitive'
module BinData
# Defines a number of classes that contain a floating point number.
# The float is defined by precision and endian.
module FloatingPoint #:nodoc: all
class << self
PRECISION = {
single: 4,
double: 8,
}
PACK_CODE = {
[:single, :little] => 'e',
[:single, :big] => 'g',
[:double, :little] => 'E',
[:double, :big] => 'G',
}
def define_methods(float_class, precision, endian)
float_class.module_eval <<-END
def do_num_bytes
#{create_num_bytes_code(precision)}
end
#---------------
private
def sensible_default
0.0
end
def value_to_binary_string(val)
#{create_to_binary_s_code(precision, endian)}
end
def read_and_return_value(io)
#{create_read_code(precision, endian)}
end
END
end
def create_num_bytes_code(precision)
PRECISION[precision]
end
def create_read_code(precision, endian)
nbytes = PRECISION[precision]
unpack = PACK_CODE[[precision, endian]]
"io.readbytes(#{nbytes}).unpack('#{unpack}').at(0)"
end
def create_to_binary_s_code(precision, endian)
pack = PACK_CODE[[precision, endian]]
"[val].pack('#{pack}')"
end
end
end
# Single precision floating point number in little endian format
class FloatLe < BinData::BasePrimitive
FloatingPoint.define_methods(self, :single, :little)
end
# Single precision floating point number in big endian format
class FloatBe < BinData::BasePrimitive
FloatingPoint.define_methods(self, :single, :big)
end
# Double precision floating point number in little endian format
class DoubleLe < BinData::BasePrimitive
FloatingPoint.define_methods(self, :double, :little)
end
# Double precision floating point number in big endian format
class DoubleBe < BinData::BasePrimitive
FloatingPoint.define_methods(self, :double, :big)
end
end
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