1const std = @import("../std.zig");
 2const math = std.math;
 3const expect = std.testing.expect;
 4
 5/// Returns whether x is a finite value.
 6pub fn isFinite(x: anytype) bool {
 7    const T = @TypeOf(x);
 8    const TBits = std.meta.Int(.unsigned, @typeInfo(T).float.bits);
 9    const remove_sign = ~@as(TBits, 0) >> 1;
10    return @as(TBits, @bitCast(x)) & remove_sign < @as(TBits, @bitCast(math.inf(T)));
11}
12
13test isFinite {
14    inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
15        // normals
16        try expect(isFinite(@as(T, 1.0)));
17        try expect(isFinite(-@as(T, 1.0)));
18
19        // zero & subnormals
20        try expect(isFinite(@as(T, 0.0)));
21        try expect(isFinite(@as(T, -0.0)));
22        try expect(isFinite(math.floatTrueMin(T)));
23
24        // other float limits
25        try expect(isFinite(math.floatMin(T)));
26        try expect(isFinite(math.floatMax(T)));
27
28        // inf & nan
29        try expect(!isFinite(math.inf(T)));
30        try expect(!isFinite(-math.inf(T)));
31        try expect(!isFinite(math.nan(T)));
32        try expect(!isFinite(-math.nan(T)));
33    }
34}