84 lines
2.3 KiB
Ruby
84 lines
2.3 KiB
Ruby
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module UnitConversion
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class Conversion
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end
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class ScaleConversion < Conversion
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def initialize(parsed_factor)
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@factor = parsed_factor
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end
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def convert(value_unit)
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value = @factor.value * value_unit.value.value
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ValueUnit.for(value, value_unit.unit, value_unit.formatter)
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end
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end
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class ConvertConversion < Conversion
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def initialize(parsed_unit, density_unit_value = nil)
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@target_unit = parsed_unit
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raise UnknownUnitError, "#{density_unit_value} is not a density" if density_unit_value && !density_unit_value.density?
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@density = density_unit_value
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end
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def convert(value_unit)
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input = value_unit.unitwise
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if value_unit.volume? && @target_unit.mass?
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raise MissingDensityError, "Cannot convert #{value_unit.unit} to #{@target_unit} without density" unless @density
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input = input * @density.unitwise
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elsif value_unit.mass? && @target_unit.volume?
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raise MissingDensityError, "Cannot convert #{value_unit.unit} to #{@target_unit} without density" unless @density
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input = input / @density.unitwise
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end
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input = input.convert_to @target_unit.unit
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formatter = @target_unit.metric? ? DecimalFormatter.new : value_unit.formatter
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ValueUnit.for(input.value, @target_unit, formatter)
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end
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end
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class AutoUnitConversion < Conversion
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def convert(value_unit)
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unless known_auto_unit?(value_unit.unit)
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return value_unit
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end
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value = value_unit.raw_value
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unit = value_unit.unit.unit
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new_unit = unit
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unit_orders = UNIT_ORDERS.values.detect { |orders| orders.include?(unit.to_sym) }
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unit_range = UNIT_RANGES[unit.to_sym]
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if value < unit_range.first
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unit_orders = unit_orders.reverse
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end
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idx = unit_orders.index(new_unit.to_sym)
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while !unit_range.include?(value) && idx < (unit_orders.length - 1)
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idx += 1
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next_unit = unit_orders[idx]
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value = Unitwise(value, new_unit).convert_to(next_unit).value
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new_unit = next_unit.to_s
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unit_range = UNIT_RANGES[new_unit.to_sym]
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end
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ValueUnit.for(value, new_unit, value_unit.formatter)
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end
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def known_auto_unit?(unit)
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unit && UNIT_ORDERS.values.flatten.include?(unit.unit.to_sym)
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end
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end
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end
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