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std: Fix sqrt for u0/u1 input types

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This commit is contained in:
LemonBoy 2021-04-14 17:52:24 +02:00
parent ebf97627fd
commit 2ebd6bd706
1 changed files with 17 additions and 3 deletions
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20
lib/std/math/sqrt.zig
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@ -39,7 +39,13 @@ pub fn sqrt(x: anytype) Sqrt(@TypeOf(x)) {
} }
} }
fn sqrt_int(comptime T: type, value: T) std.meta.Int(.unsigned, @typeInfo(T).Int.bits / 2) { fn sqrt_int(comptime T: type, value: T) Sqrt(T) {
switch (T) {
u0 => return 0,
u1 => return value,
else => {},
}
var op = value; var op = value;
var res: T = 0; var res: T = 0;
var one: T = 1 << (@typeInfo(T).Int.bits - 2); var one: T = 1 << (@typeInfo(T).Int.bits - 2);
@ -58,11 +64,13 @@ fn sqrt_int(comptime T: type, value: T) std.meta.Int(.unsigned, @typeInfo(T).Int
one >>= 2; one >>= 2;
} }
const ResultType = std.meta.Int(.unsigned, @typeInfo(T).Int.bits / 2); const ResultType = Sqrt(T);
return @intCast(ResultType, res); return @intCast(ResultType, res);
} }
test "math.sqrt_int" { test "math.sqrt_int" {
expect(sqrt_int(u0, 0) == 0);
expect(sqrt_int(u1, 1) == 1);
expect(sqrt_int(u32, 3) == 1); expect(sqrt_int(u32, 3) == 1);
expect(sqrt_int(u32, 4) == 2); expect(sqrt_int(u32, 4) == 2);
expect(sqrt_int(u32, 5) == 2); expect(sqrt_int(u32, 5) == 2);
@ -74,7 +82,13 @@ test "math.sqrt_int" {
/// Returns the return type `sqrt` will return given an operand of type `T`. /// Returns the return type `sqrt` will return given an operand of type `T`.
pub fn Sqrt(comptime T: type) type { pub fn Sqrt(comptime T: type) type {
return switch (@typeInfo(T)) { return switch (@typeInfo(T)) {
.Int => |int| std.meta.Int(.unsigned, int.bits / 2), .Int => |int| {
return switch (int.bits) {
0 => u0,
1 => u1,
else => std.meta.Int(.unsigned, int.bits / 2),
};
},
else => T, else => T,
}; };
} }