Class: BaseN::Encoder

Inherits:
Object
  • Object
show all
Defined in:
lib/base_n.rb

Constant Summary collapse

PRIMITIVES = 
((0..9).collect { |i| i.to_s } + ('A'..'Z').to_a + ('a'..'z').to_a + %w(! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \\ ] ^ _ ` { | } ~)).map(&:freeze).freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(base) ⇒ Encoder

Returns a new instance of Encoder.



23
24
25
26
27
 
# File 'lib/base_n.rb', line 23

def initialize base
  self.base = base
  raise "I only support bases 2 and above" if base < 2
  raise "I only support up to base #{primitives.size}" if base > primitives.size
end

Instance Attribute Details

#base ⇒ Object

Returns the value of attribute base.



21
22
23
 
# File 'lib/base_n.rb', line 21

def base
  @base
end

Class Method Details

.highest_supported ⇒ Object 



29
30
31
 
# File 'lib/base_n.rb', line 29

def self.highest_supported
  new PRIMITIVES.size
end

Instance Method Details

#case_sensitive? ⇒ Boolean

Returns:

  • (Boolean) 


33
34
35
 
# File 'lib/base_n.rb', line 33

def case_sensitive?
  base > 36
end

#decode(subject) ⇒ Object 



41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
 
# File 'lib/base_n.rb', line 41

def decode subject
  r = subject.representation
  r.upcase! unless Encoder.new(subject.base).case_sensitive?
  s = r.reverse.split('')

  total = 0
  s.each_with_index do |char, index|
    if ord = primitives.index(char)
      total += ord * (base ** index)
    else
      raise ArgumentError, "#{subject} has #{char} which is not valid"
    end
  end
  total
end

#encode(subject) ⇒ Object 



57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
 
# File 'lib/base_n.rb', line 57

def encode subject
  subject = Number.new subject.to_s, 10 unless subject.kind_of? BaseN::Number
  return subject if subject.base == base

  i = Encoder.new(subject.base).decode(subject)

  s = ''

  while i > 0
    s << primitives[i.modulo(base)]
    i /= base
  end
  s = '0' if s == ''
  Number.new s.reverse, base
end

#primitives ⇒ Object 



37
38
39
 
# File 'lib/base_n.rb', line 37

def primitives
  PRIMITIVES[0, base]
end