Module: Bitindex::Common

Included in:
Reader, Writer
Defined in:
lib/bitindex/common.rb

Constant Summary collapse

SIGNED_16BIT = 
2**15 / 8
UNSIGNED_16BIT = 
2**16 / 8
SIGNED_32BIT = 
2**31 / 8
UNSIGNED_32BIT = 
2**32 / 8

Instance Method Summary collapse

Instance Method Details

#bit_set?(byte, value, ltor = true) ⇒ Boolean

Returns:

  • (Boolean) 


10
11
12
13
 
# File 'lib/bitindex/common.rb', line 10

def bit_set? byte, value, ltor = true
  mask = build_mask value, ltor
  (byte & mask) != 0
end

#build_mask(value, ltor = true) ⇒ Object 



30
31
32
33
34
35
36
37
 
# File 'lib/bitindex/common.rb', line 30

def build_mask value, ltor = true
  shift = value & 0x07
  if ltor
    (0x80 >> shift)
  else
    (0x01 << shift)
  end
end

#byte_pos(value) ⇒ Object 



26
27
28
 
# File 'lib/bitindex/common.rb', line 26

def byte_pos value
  (value >> 3)
end

#set_bit(byte, value, ltor = true) ⇒ Object 



15
16
17
18
 
# File 'lib/bitindex/common.rb', line 15

def set_bit byte, value, ltor = true
  mask = build_mask value, ltor
  (byte | mask)
end

#unset_bit(byte, value, ltor = true) ⇒ Object 



20
21
22
23
24
 
# File 'lib/bitindex/common.rb', line 20

def unset_bit byte, value, ltor = true
  mask = build_mask value, ltor
  mask ^= 0xff
  (byte & mask)
end