Bitmap.Binary
Contains functions to create and work with a bitmap
Bitmaps are also known as bit arrays, bit sets and is a fast space efficient data structure for lookups
The module has been designed to be pipe-friendly, so pipe ‘em up
Summary
at(bitmap, index) | Returns the bit value at |
inspect(bitmap) | Inspects the bitmap and returns the string representation of the bitmap |
new(argument) | Creates and returns a bitmap of size corresponding to the |
set(bitmap, index) | Sets the bit at |
set?(bitmap, index) | Returns a boolean representing whether the bit at position |
set_all(bitmap) | Set all bits in the bitmap and returns a new bitmap |
to_string(bitmap) | Returns the string representation of the bitmap |
toggle(bitmap, index) | Toggles the bit at |
toggle_all(bitmap) | Toggles all bits in the bitmap and returns a new bitmap |
unset(bitmap, index) | Unsets the bit at |
unset?(bitmap, index) | Returns a boolean representing whether the bit at position |
unset_all(bitmap) | Unsets all bits in the bitmap and returns a new bitmap |
Types
t :: binary
index :: non_neg_integer
bit :: 1 | 0
Functions
Specs:
- at(Bitmap.Binary.t, index) :: bit
Returns the bit value at index
in the bitmap
Examples
iex> bm = Bitmap.Binary.new(5)
iex> Bitmap.Binary.at(bm, 2)
0
iex> bm = Bitmap.Binary.set(bm, 2)
iex> Bitmap.Binary.at(bm, 2)
1
Specs:
- inspect(Bitmap.Binary.t) :: String.t
Inspects the bitmap and returns the string representation of the bitmap
Note: This can be very long for huge bitmaps.
Specs:
- new(argt) :: Bitmap.Binary.t
Creates and returns a bitmap of size corresponding to the argument
passed.
If argument
is
- integer, size of bitmap is equal to the
argument
- range, size of bitmap is equal to the length of
argument
- list, size of bitmap is equal to the length of
argument
Note: All bits are set to 0 by default
Examples
iex> Bitmap.Binary.new(400)
<<0::size(400)>>
iex> Bitmap.Binary.new([1,2,3,4,5])
<<0::size(5)>>
iex> Bitmap.Binary.new(1..25)
<<0::size(25)>>
Specs:
- set(Bitmap.Binary.t, index) :: Bitmap.Binary.t
Sets the bit at index
in the bitmap and returns the new bitmap
Index can also have a value :all
in which case all bits
will be set like in set_all
Examples
iex> Bitmap.Binary.set(Bitmap.Binary.new(5), 3)
<<2::size(5)>>
iex> Bitmap.Binary.set(Bitmap.Binary.new(1..10), 2)
<<32, 0::size(2)>>
Specs:
- set?(Bitmap.Binary.t, index) :: boolean
Returns a boolean representing whether the bit at position index
is set or not
Examples
iex> bm = Bitmap.Binary.new(5) |> Bitmap.Binary.set(1) |> Bitmap.Binary.set(3)
iex> Bitmap.Binary.set?(bm, 1)
true
iex> Bitmap.Binary.set?(bm, 4)
false
Specs:
- set_all(Bitmap.Binary.t) :: Bitmap.Binary.t
Set all bits in the bitmap and returns a new bitmap
Examples
iex> Bitmap.Binary.set_all(Bitmap.Binary.new(10))
<<255, 3::size(2)>>
iex> Bitmap.Binary.set_all(Bitmap.Binary.new(100))
<<255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 15::size(4)>>
Specs:
- to_string(Bitmap.Binary.t) :: String.t
Returns the string representation of the bitmap
Note: This can be very long for huge bitmaps.
Specs:
- toggle(Bitmap.Binary.t, index) :: Bitmap.Binary.t
Toggles the bit at index
in the bitmap and returns the new bitmap
i.e. it sets the bit to 1 if it was 0 or sets the bit to 0 if it was 1
Index can also have a value :all
in which case all bits will be toggled
like in toggle_all
Examples
iex> bm = Bitmap.Binary.new(10) |> Bitmap.Binary.set(4) |> Bitmap.Binary.set(8)
iex> Bitmap.Binary.toggle(bm, 3)
<<24, 2::size(2)>>
iex> Bitmap.Binary.toggle(bm, 6)
<<10, 2::size(2)>>
Specs:
- toggle_all(Bitmap.Binary.t) :: Bitmap.Binary.t
Toggles all bits in the bitmap and returns a new bitmap
Examples
iex> bm = Bitmap.Binary.new(10) |> Bitmap.Binary.set(4) |> Bitmap.Binary.set(8)
iex> Bitmap.Binary.toggle_all(bm)
<<247, 1::size(2)>>
Specs:
- unset(Bitmap.Binary.t, index) :: Bitmap.Binary.t
Unsets the bit at index
in the bitmap and returns the new bitmap
Index can also have a value :all
in which case all bits
will be unset like in unset_all
Examples
iex> bm = Bitmap.Binary.new(10) |> Bitmap.Binary.set(4) |> Bitmap.Binary.set(8)
iex> Bitmap.Binary.unset(bm, 4)
<<0, 2::size(2)>>
iex> Bitmap.Binary.unset(bm, 8)
<<8, 0::size(2)>>
Specs:
- unset?(Bitmap.Binary.t, index) :: boolean
Returns a boolean representing whether the bit at position index
is unset or not
Examples
iex> bm = Bitmap.Binary.new(5) |> Bitmap.Binary.set(1) |> Bitmap.Binary.set(3)
iex> Bitmap.Binary.unset?(bm, 1)
false
iex> Bitmap.Binary.unset?(bm, 4)
true
Specs:
- unset_all(Bitmap.Binary.t) :: Bitmap.Binary.t
Unsets all bits in the bitmap and returns a new bitmap
Examples
iex> bm = Bitmap.Binary.new(10) |> Bitmap.Binary.set(4) |> Bitmap.Binary.set(8)
iex> Bitmap.Binary.unset_all(bm)
<<0, 0::size(2)>>