/
integer.ex
225 lines (181 loc) · 5.79 KB
/
integer.ex
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defmodule Zig.Type.Integer do
use Zig.Type, inspect?: true
defstruct [:signedness, :bits]
@type t :: %__MODULE__{
signedness: :unsigned | :signed,
bits: 0..65_535 | :big
}
def parse("u" <> number_str = t) do
%__MODULE__{signedness: :unsigned, bits: get_bits!(number_str, t)}
end
def parse("i" <> number_str = t) do
%__MODULE__{signedness: :signed, bits: get_bits!(number_str, t)}
end
def parse(other), do: raise(Zig.Type.ParseError, source: other)
@signs %{"signed" => :signed, "unsigned" => :unsigned}
def from_json(%{"signedness" => s, "bits" => b}) do
%__MODULE__{signedness: Map.fetch!(@signs, s), bits: b}
end
def get_bits!(number_str, full_type) do
case Integer.parse(number_str) do
{n, ""} when n in 0..65_535 ->
n
{n, ""} ->
raise Zig.Type.ParseError,
source: full_type,
reason: "#{n} is out of range of zig bit lengths"
_ ->
raise Zig.Type.ParseError, source: full_type
end
end
def to_string(integer) do
case integer.signedness do
:unsigned -> "u#{integer.bits}"
:signed -> "i#{integer.bits}"
end
end
def to_call(integer), do: to_string(integer)
def inspect(type, _opts) do
import Inspect.Algebra
concat(["~t(", to_string(type), ")"])
end
def marshals_param?(%{bits: bits}), do: bits > 64
def marshals_return?(%{bits: bits}), do: bits > 64
def marshal_param(type, variable, index, :elixir) do
marshal_param_elixir(type, variable, index)
end
def marshal_param(type, variable, index, :erlang) do
marshal_param_erlang(type, variable, index)
end
defp marshal_param_elixir(type, variable, index) do
max = typemax(type)
min = typemin(type)
guards =
quote bind_quoted: [
variable: variable,
name: to_string(type),
index: index,
max: max,
min: min
] do
unless is_integer(variable) do
:erlang.error(
{:argument_error, index,
[{"expected: integer (for `#{name}`)"}, {"got: `#{inspect(variable)}`"}]}
)
end
unless variable >= min do
:erlang.error(
{:argument_error, index,
[
{"expected: integer (for `#{name}`)"},
{"got: `#{inspect(variable)}`"},
{"note: out of bounds (#{min}..#{max})"}
]}
)
end
unless variable <= max do
:erlang.error(
{:argument_error, index,
[
{"expected: integer (for `#{name}`)"},
{"got: `#{inspect(variable)}`"},
{"note: out of bounds (#{min}..#{max})"}
]}
)
end
end
size = _next_power_of_two_ceil(type.bits)
case type.signedness do
:unsigned ->
quote do
unquote(guards)
unquote(variable) = <<unquote(variable)::unsigned-integer-size(unquote(size))-native>>
end
:signed ->
quote do
unquote(guards)
unquote(variable) = <<unquote(variable)::signed-integer-size(unquote(size))-native>>
end
end
end
defp marshal_param_erlang(type, variable, _index) do
max = typemax(type)
min = typemin(type)
size = _next_power_of_two_ceil(type.bits)
"""
#{variable}_m = case #{variable} of
X when not is_integer(X) ->
erlang:error(badarg);
X when X < #{min} ->
erlang:error(badarg);
X when X > #{max} ->
erlang:error(badarg);
X -> <<X:#{size}/native-#{type.signedness}-integer-unit:1>>
end,
"""
end
def marshal_return(type, variable, :elixir) do
marshal_return_elixir(type, variable)
end
def marshal_return(type, variable, :erlang) do
marshal_return_erlang(type, variable)
end
defp marshal_return_elixir(type, variable) do
size = _next_power_of_two_ceil(type.bits)
case type.signedness do
:unsigned ->
quote do
<<result::unsigned-integer-size(unquote(size))-native>> = unquote(variable)
result
end
:signed ->
quote do
<<result::signed-integer-size(unquote(size))-native>> = unquote(variable)
result
end
end
end
defp marshal_return_erlang(type, variable) do
size = _next_power_of_two_ceil(type.bits)
"""
<<NumberResult:#{size}/native-#{type.signedness}-integer>> = #{variable},
NumberResult
"""
end
def _next_power_of_two_ceil(bits), do: _next_power_of_two_ceil(bits, 1, true)
defp _next_power_of_two_ceil(bits, so_far, all_zeros) do
import Bitwise
shifted = bits >>> 1
case {shifted, all_zeros} do
{1, true} ->
1 <<< so_far
{1, false} ->
2 <<< so_far
_ ->
all_zeros = all_zeros && (bits &&& 1) == 0
_next_power_of_two_ceil(shifted, so_far + 1, all_zeros)
end
end
def spec(%{bits: 0}, _, _), do: 0
def spec(%{signedness: :unsigned} = type, _, _opts) do
quote context: Elixir do
0..unquote(typemax(type))
end
end
def spec(%{signedness: :signed} = type, _, _opts) do
neg_typemin = -typemin(type)
quote context: Elixir do
-unquote(neg_typemin)..unquote(typemax(type))
end
end
# note that we're currently not using this function for unsigned ints, which we know is zero
defp typemin(%{signedness: :signed, bits: 0}), do: 0
defp typemin(%{signedness: :signed, bits: bits}), do: -Bitwise.<<<(1, bits - 1)
defp typemin(%{signedness: :unsigned}), do: 0
defp typemax(%{bits: 0}), do: 0
defp typemax(%{signedness: :unsigned, bits: bits}), do: Bitwise.<<<(1, bits) - 1
defp typemax(%{signedness: :signed, bits: 1}), do: 0
defp typemax(%{signedness: :signed, bits: bits}), do: Bitwise.<<<(1, bits - 1) - 1
def return_allowed?(_), do: true
end