207 lines
3.7 KiB
Elixir
207 lines
3.7 KiB
Elixir
defmodule Bitwise do
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@moduledoc """
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This module provides macro-based operators that perform calculations
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on (sets of) bits. In general, you should `use` the Bitwise module
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as a whole:
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iex> use Bitwise
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iex> bnot 1
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-2
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iex> 1 &&& 1
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1
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When used, it accepts the following options:
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* `:only_operators` - include only operators
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* `:skip_operators` - skip operators
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iex> use Bitwise, only_operators: true
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iex> 1 &&& 1
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1
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These macros can be used in guards:
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iex> use Bitwise
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iex> odd? = fn(int) when band(int, 1) == 1 -> true; (_) -> false end
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iex> odd?.(1)
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true
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"""
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@doc false
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defmacro __using__(options) do
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except = cond do
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Keyword.get(options, :only_operators) ->
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[bnot: 1, band: 2, bor: 2, bxor: 2, bsl: 2, bsr: 2]
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Keyword.get(options, :skip_operators) ->
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[~~~: 1, &&&: 2, |||: 2, ^^^: 2, <<<: 2, >>>: 2]
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true -> []
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end
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quote do
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import Bitwise, except: unquote(except)
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end
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end
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@doc """
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Calculates the bitwise NOT of its argument.
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iex> bnot(2)
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-3
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iex> bnot(2) &&& 3
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1
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"""
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defmacro bnot(expr) do
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quote do: :erlang.bnot(unquote(expr))
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end
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@doc """
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Prefix (unary) operator; calculates the bitwise NOT of its argument.
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iex> ~~~2
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-3
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iex> ~~~2 &&& 3
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1
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"""
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defmacro ~~~expr do
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quote do: :erlang.bnot(unquote(expr))
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end
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@doc """
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Calculates the bitwise AND of its arguments.
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iex> band(9, 3)
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1
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"""
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defmacro band(left, right) do
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quote do: :erlang.band(unquote(left), unquote(right))
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end
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@doc """
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Infix operator; calculates the bitwise AND of its arguments.
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iex> 9 &&& 3
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1
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"""
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defmacro left &&& right do
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quote do: :erlang.band(unquote(left), unquote(right))
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end
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@doc """
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Calculates the bitwise OR of its arguments.
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iex> bor(9, 3)
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11
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"""
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defmacro bor(left, right) do
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quote do: :erlang.bor(unquote(left), unquote(right))
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end
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@doc """
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Infix operator; calculates the bitwise OR of its arguments.
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iex> 9 ||| 3
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11
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"""
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defmacro left ||| right do
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quote do: :erlang.bor(unquote(left), unquote(right))
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end
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@doc """
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Calculates the bitwise XOR of its arguments.
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iex> bxor(9, 3)
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10
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"""
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defmacro bxor(left, right) do
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quote do: :erlang.bxor(unquote(left), unquote(right))
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end
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@doc """
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Infix operator; calculates the bitwise XOR of its arguments.
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iex> 9 ^^^ 3
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10
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"""
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defmacro left ^^^ right do
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quote do: :erlang.bxor(unquote(left), unquote(right))
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end
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@doc """
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Calculates the result of an arithmetic left bitshift.
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iex> bsl(1, 2)
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4
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iex> bsl(1, -2)
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0
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iex> bsl(-1, 2)
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-4
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iex> bsl(-1, -2)
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-1
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"""
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defmacro bsl(left, right) do
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quote do: :erlang.bsl(unquote(left), unquote(right))
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end
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@doc """
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Infix operator; calculates the result of an arithmetic left bitshift.
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iex> 1 <<< 2
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4
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iex> 1 <<< -2
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0
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iex> -1 <<< 2
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-4
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iex> -1 <<< -2
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-1
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"""
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defmacro left <<< right do
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quote do: :erlang.bsl(unquote(left), unquote(right))
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end
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@doc """
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Calculates the result of an arithmetic right bitshift.
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iex> bsr(1, 2)
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0
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iex> bsr(1, -2)
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4
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iex> bsr(-1, 2)
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-1
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iex> bsr(-1, -2)
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-4
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"""
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defmacro bsr(left, right) do
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quote do: :erlang.bsr(unquote(left), unquote(right))
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end
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@doc """
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Infix operator; calculates the result of an arithmetic left bitshift.
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iex> 1 >>> 2
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0
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iex> 1 >>> -2
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4
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iex> -1 >>> 2
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-1
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iex> -1 >>> -2
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-4
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"""
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defmacro left >>> right do
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quote do: :erlang.bsr(unquote(left), unquote(right))
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end
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end
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