Module: Tins::Unit

Defined in:
lib/tins/unit.rb

Defined Under Namespace

Classes: FormatParser, ParserError, Prefix, UnitParser

Constant Summary collapse

PREFIX_LC = 
[
  '', 'k', 'm', 'g', 't', 'p', 'e', 'z', 'y',
].each_with_index.map { |n, i| Prefix.new(n.freeze, 1000, 1000 ** i, false) }.freeze
PREFIX_UC = 
[
  '', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y',
].each_with_index.map { |n, i| Prefix.new(n.freeze, 1024, 1024 ** i, false) }.freeze
PREFIX_F = 
[
  '', 'm', 'ยต', 'n', 'p', 'f', 'a', 'z', 'y',
].each_with_index.map { |n, i| Prefix.new(n.freeze, 1000, 1000 ** -i, true) }.freeze

Class Method Summary collapse

Class Method Details

.format(value, format: '%f %U', prefix: 1024, unit: ?b) ⇒ Object 



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# File 'lib/tins/unit.rb', line 36

def format(value, format: '%f %U', prefix: 1024, unit: ?b)
  prefixes = prefixes(prefix)
  first_prefix = prefixes.first or
    raise ArgumentError, 'a non-empty array of prefixes is required'
  if value.zero?
    result = format.sub('%U', unit)
    result %= value
  else
    prefix = prefixes[
      (first_prefix.fraction ? -1 : 1) * Math.log(value.abs) / Math.log(first_prefix.step)
    ]
    result = format.sub('%U', "#{prefix.name}#{unit}")
    result %= (value / prefix.multiplier.to_f)
  end
end

.parse(string, format: '%f %U', unit: ?b, prefix: nil) ⇒ Object

Parse the string string if it matches format with the unit unit and the prefixes specified by prefix.



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# File 'lib/tins/unit.rb', line 169

def parse(string, format: '%f %U', unit: ?b, prefix: nil)
  prefixes = prefixes(prefix)
  FormatParser.new(format, UnitParser.new(string, unit, prefixes)).parse
end

.parse?(string, **options) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tins/unit.rb', line 174

def parse?(string, **options)
  parse(string, **options)
rescue ParserError
  nil
end

.prefixes(identifier) ⇒ Object 



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# File 'lib/tins/unit.rb', line 23

def prefixes(identifier)
  case identifier
  when :uppercase, :uc, 1024
    PREFIX_UC
  when :lowercase, :lc, 1000
    PREFIX_LC
  when :fraction, :f, 0.001
    PREFIX_F
  when Array
    identifier
  end
end