zig/lib/std/math/isfinite.zig
mlugg 0fe3fd01dd
std: update std.builtin.Type fields to follow naming conventions
The compiler actually doesn't need any functional changes for this: Sema
does reification based on the tag indices of `std.builtin.Type` already!
So, no zig1.wasm update is necessary.

This change is necessary to disallow name clashes between fields and
decls on a type, which is a prerequisite of #9938.
2024-08-28 08:39:59 +01:00

35 lines
1.1 KiB
Zig

const std = @import("../std.zig");
const math = std.math;
const expect = std.testing.expect;
/// Returns whether x is a finite value.
pub fn isFinite(x: anytype) bool {
const T = @TypeOf(x);
const TBits = std.meta.Int(.unsigned, @typeInfo(T).float.bits);
const remove_sign = ~@as(TBits, 0) >> 1;
return @as(TBits, @bitCast(x)) & remove_sign < @as(TBits, @bitCast(math.inf(T)));
}
test isFinite {
inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
// normals
try expect(isFinite(@as(T, 1.0)));
try expect(isFinite(-@as(T, 1.0)));
// zero & subnormals
try expect(isFinite(@as(T, 0.0)));
try expect(isFinite(@as(T, -0.0)));
try expect(isFinite(math.floatTrueMin(T)));
// other float limits
try expect(isFinite(math.floatMin(T)));
try expect(isFinite(math.floatMax(T)));
// inf & nan
try expect(!isFinite(math.inf(T)));
try expect(!isFinite(-math.inf(T)));
try expect(!isFinite(math.nan(T)));
try expect(!isFinite(-math.nan(T)));
}
}