Class: BinaryopsString

Inherits:
String
  • Object
show all
Defined in:
lib/indis-core/binaryops_string.rb

Overview

BinaryopsString manages bitwise operations on a String. This is useful when you expect bitstrings with meaningful leading zeroes.

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from String

#to_bo

Constructor Details

#initialize(s) ⇒ BinaryopsString

BinaryopsString can be initialized either from a String or a Fixnum

Parameters:



24
25
26
27
28
29
30
 
# File 'lib/indis-core/binaryops_string.rb', line 24

def initialize(s)
  if s.class == Fixnum
    super s.to_s(2)
  else
    super
  end
end

Class Method Details

.zeroes(n) ⇒ Object

Returns a new BinaryopsString filled in with zeroes of given length



127
128
129
 
# File 'lib/indis-core/binaryops_string.rb', line 127

def self.zeroes(n)
  BinaryopsString.new('0'*n)
end

Instance Method Details

#<<(amount) ⇒ Object

Performs a LSL operation

Returns:

  • a new BinaryopsString with result



102
103
104
105
106
 
# File 'lib/indis-core/binaryops_string.rb', line 102

def <<(amount)
  return self if amount == 0
  z = BinaryopsString.zeroes(amount)
  concat(z).bits(self.length-1, 0)
end

#>>(amount) ⇒ Object

Performs a LSR operation

Returns:

  • a new BinaryopsString with result



110
111
112
113
114
 
# File 'lib/indis-core/binaryops_string.rb', line 110

def >>(amount)
  return self if amount == 0
  z = BinaryopsString.zeroes(amount)
  z.concat(self).rbits(0, self.length-1)
end

#bit(i) ⇒ Object

Returns a Fixnum with given bit value (rightmost bit is 0).

Parameters:

  • i (Fixnum) —

    the bit in question

Returns:

  • a Fixnum with given bit value (rightmost bit is 0)



60
61
62
 
# File 'lib/indis-core/binaryops_string.rb', line 60

def bit(i)
  self[~i].to_i
end

#bits(from, to) ⇒ Object

Returns a new BinaryopsString with a given slice (rightmost bit is 0).

Parameters:

  • from (Fixnum) —

    first bit (inclusive)

  • to (Fixnum) —

    last bit (inclusive)

Returns:

  • a new BinaryopsString with a given slice (rightmost bit is 0)



47
48
49
 
# File 'lib/indis-core/binaryops_string.rb', line 47

def bits(from, to)
  BinaryopsString.new(self.to_s[~from..~to])
end

#concat(other) ⇒ Object

Concatenates the receiver with another BinaryopsString

Returns:

  • a new BinaryopsString with result



80
81
82
 
# File 'lib/indis-core/binaryops_string.rb', line 80

def concat(other)
  BinaryopsString.new(self.to_s + other.to_s)
end

#rbit(i) ⇒ Object

Returns a Fixnum with given bit value (leftmost bit is 0).

Parameters:

  • i (Fixnum) —

    the bit in question

Returns:

  • a Fixnum with given bit value (leftmost bit is 0)



66
67
68
 
# File 'lib/indis-core/binaryops_string.rb', line 66

def rbit(i)
  self[i].to_i
end

#rbits(from, to) ⇒ Object

Returns a new BinaryopsString with a given slice (leftmost bit is 0).

Parameters:

  • from (Fixnum) —

    first bit (inclusive)

  • to (Fixnum) —

    last bit (inclusive)

Returns:

  • a new BinaryopsString with a given slice (leftmost bit is 0)



54
55
56
 
# File 'lib/indis-core/binaryops_string.rb', line 54

def rbits(from, to)
  BinaryopsString.new(self.to_s[from..to])
end

#ror(amount) ⇒ Object

Performs a ROR operation (cyclic LSR)

Returns:

  • a new BinaryopsString with result



118
119
120
121
122
123
124
 
# File 'lib/indis-core/binaryops_string.rb', line 118

def ror(amount)
  return self if amount == 0
  s = self.to_s
  moveover = s[-amount..-1]
  movable = s[0...-amount]
  BinaryopsString.new(moveover + movable)
end

#sign_extend(len) ⇒ Object

Sign-extends the receiver to given length (left padding)

Returns:

  • a new BinaryopsString with result



94
95
96
97
98
 
# File 'lib/indis-core/binaryops_string.rb', line 94

def sign_extend(len)
  return self unless len-self.length > 0
  zbs = self[0]*(len-self.length)
  BinaryopsString.new(zbs + self.to_s)
end

#to_i ⇒ Object

Outputs an unsigned int value of self



33
34
35
 
# File 'lib/indis-core/binaryops_string.rb', line 33

def to_i
  super 2
end

#to_signed_i ⇒ Object

Outputs a signed int value of self



38
39
40
41
42
 
# File 'lib/indis-core/binaryops_string.rb', line 38

def to_signed_i
  return to_i if self[0] == '0'
  complement = ('1'*(self.length)).to_i(2) - to_i + 1
  -complement
end

#zero_extend(len) ⇒ Object

Zero-extends the receiver to given length (left padding)

Returns:

  • a new BinaryopsString with result



86
87
88
89
90
 
# File 'lib/indis-core/binaryops_string.rb', line 86

def zero_extend(len)
  return self unless len-self.length > 0
  zbs = '0'*(len-self.length)
  BinaryopsString.new(zbs + self.to_s)
end

#|(other) ⇒ Object

Performs an OR operation

Returns:

  • a new BinaryopsString with result

Raises:

  • (ArgumentError) —

    when BinaryopsString lengths don’t match



73
74
75
76
 
# File 'lib/indis-core/binaryops_string.rb', line 73

def |(other)
  raise ArgumentError unless self.length == other.length
  BinaryopsString.new(self.to_i | other.to_i).zero_extend(self.length)
end