Class: AllYourBase::Are

Inherits:
Object
  • Object
show all
Defined in:
lib/all_your_base/are.rb,
lib/all_your_base/are/belong_to_us.rb

Defined Under Namespace

Modules: BelongToUs

Constant Summary collapse

BASE_62_CHARSET =

This charset works for “standard” bases 2-36 and 62. It also provides non-standard bases 1 and 37-61 for most uses.

('0'..'9').to_a + ('A'..'Z').to_a + ('a'..'z').to_a
BASE_64_CHARSET =

This is the base64 encoding charset, but note that this library does not provide true base64 encoding.

('A'..'Z').to_a + ('a'..'z').to_a + ('0'..'9').to_a +
['+', '/']
BASE_78_CHARSET =

This is a maximum URL safe charset (between /‘s). Not all sites know or care about the validity of these characters.

BASE_62_CHARSET + ['!', '$', '&', "'", '(', ')', '*', '+',
',', '-', '.', ':', ';', '=', '@', '_']

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(charset, options = {}) ⇒ Are

Returns a new instance of Are.



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# File 'lib/all_your_base/are.rb', line 18

def initialize(charset, options={})
  options[:radix] ||= charset.size
  if charset.size < 1 || charset.size < options[:radix]
    raise ArgumentError.new('charset too small ' << charset.size.to_s)
  elsif options[:radix] < 1
    raise ArgumentError.new('illegal radix ' << options[:radix].to_s)
  elsif charset.include?('-') && options[:honor_negation]
    raise ArgumentError.new('"-" is unsupported in charset when honor_negation is set')
  end

  @charset = charset
  @options = options
end

Class Method Details

.convert_from_base_10(int, charset, options = {}) ⇒ Object 



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# File 'lib/all_your_base/are.rb', line 60

def self.convert_from_base_10(int, charset, options={})
  ayb = self.new(charset, options)
  ayb.convert_from_base_10(int)
end

.convert_to_base_10(string, charset, options = {}) ⇒ Object 



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# File 'lib/all_your_base/are.rb', line 55

def self.convert_to_base_10(string, charset, options={})
  ayb = self.new(charset, options)
  ayb.convert_to_base_10(string)
end

Instance Method Details

#convert_from_base_10(int) ⇒ Object 



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# File 'lib/all_your_base/are.rb', line 65

def convert_from_base_10(int)
  if !int.to_s.match(/\A-?[0-9]+\Z/)
    raise ArgumentError.new('invalid characters')
  end
  int = int.to_i
  return '0' if int == 0

  negate = false
  if @options[:honor_negation]
    negate = int < 0
  end
  int = int.abs
  
  if @options[:radix] == 1
    result = @charset.first * int
  else
    s = ''
    while int > 0
      s << @charset[int.modulo(@options[:radix])]
      int /= @options[:radix]
    end
    result = s.reverse
  end
  return ((negate ? '-' : '') << result)
end

#convert_to_base_10(string) ⇒ Object 



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# File 'lib/all_your_base/are.rb', line 32

def convert_to_base_10(string)
  negate = false
  if @options[:honor_negation]
    negate = string[0...1] == '-'
    string = string[1...string.size] if negate
  end

  if string.size < 1
    raise ArgumentError.new('string too small ' << string.size.to_s)
  end
  if !string.match(/\A[#{Regexp.escape(@charset[0...@options[:radix]].join(''))}]+\Z/)
    raise ArgumentError.new('invalid characters')
  end
  regexp = Regexp.new(@charset.map{|c| Regexp.escape(c)}.join('|'))
  result = 0
  index = 0
  string.reverse.scan(regexp) do |c|
    result += @charset.index(c) * (@options[:radix] ** index)
    index += 1
  end
  return result * (negate ? -1 : 1)
end