Class: EncodeId

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(max_digits = 6, grows = false) ⇒ EncodeId

Returns a new instance of EncodeId.



6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
 
# File 'lib/encode_id.rb', line 6

def initialize(max_digits=6, grows=false)
  @base=[
    'VaRCScev0fNjk9HDGlmTobPq7rIsYtux5yzAgBE4pFihUJnK3LMd1Q6XZ',
    'JK3LMNtuvx5yzABCDE4FGHIP1QRSTUV6XYZabcde0fghijk9lmnopq7rs',
    'STUV6XYZabcde0fghijk9lmK3LMNnopq7rstuvP1QRx5yzABCDE4FGHIJ',
    'P1QRk9lmnopq7rsSTdzABCDEuJK3LMN4FGHe0fghijtvx5yUV6XYZabcI',
    'lmnopDE4FGHe0fghijtuJK3LMNvx5q7rsSTdzABCIPyUV6XYZabc1QRk9',
    'vx5yzABCDE4FGHUV6XYZk9lmnopq7rsP1QRSTde0fghijtuabcIJK3LMN',
    'TdzABCIPyUV6XYZabc1QRk9lmnopDE4FGHe0fghijtuJK3LMNvx5q7rsS',
    'QRSTde0fghijtuabcIJK3LMNvx5yzABCDE4FGHUV6XYZk9lmnopq7rsP1',
    '4FGHe0fghijtP1QRk9lmnopq7rsSTdzABCDEuJK3LMNvx5yUV6XYZabcI',
    'q7rsSTdzABCIPyUV6XYZabc1QRk9lmnopDE4FGHe0fghijtuJK3LMNvx5',
  ]
    @max_digits = max_digits
    @grows = grows
    @base_len = @base.length()
    @n_base = @base[0].length()
end

Instance Attribute Details

#grows ⇒ Object (readonly)

Returns the value of attribute grows.



4
5
6
 
# File 'lib/encode_id.rb', line 4

def grows
  @grows
end

#max_digits ⇒ Object (readonly)

Returns the value of attribute max_digits.



3
4
5
 
# File 'lib/encode_id.rb', line 3

def max_digits
  @max_digits
end

Instance Method Details

#decode(c) ⇒ Object 



42
43
44
45
46
47
48
49
50
51
 
# File 'lib/encode_id.rb', line 42

def decode(c)
  id = 0
  x = 1
  for bit in 0..c.length() - 1
    v = @base[bit % @base_len].index(c[bit])
    id += v * x
    x *= @n_base
  end
  return id
end

#encode(id) ⇒ Object 



25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
 
# File 'lib/encode_id.rb', line 25

def encode(id)
  if(!@grows && id > max = self.max_id())
    raise "Limit id(#{id}) for #{@max_digits} digits(#{max}) in EncodeId.encode, possible lost of information"
  end
  ret = ''
  aux = id
  bit = 0
  while (@grows && aux) || (@max_digits > bit) do
    a = aux % @n_base
    ret.concat(@base[bit % @base_len][a])
    aux = (aux - a) / @n_base
    bit += 1
  end
  return ret
end

#max_alias ⇒ Object 



54
55
56
57
58
59
60
 
# File 'lib/encode_id.rb', line 54

def max_alias
  a = ''
  for bit in 0..@max_digits
    a.concat(@base[bit % @base_len][-1])
  end
  return a
end

#max_id ⇒ Object 



63
64
65
 
# File 'lib/encode_id.rb', line 63

def max_id()
  @n_base.pow(@max_digits)
end