1const std = @import("../std.zig");
2const math = std.math;
3const expect = std.testing.expect;
4
5/// Returns whether x is an infinity, ignoring sign.
6pub inline fn isInf(x: anytype) bool {
7 const T = @TypeOf(x);
8 const TBits = @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
13/// Returns whether x is an infinity with a positive sign.
14pub inline fn isPositiveInf(x: anytype) bool {
15 return x == math.inf(@TypeOf(x));
16}
17
18/// Returns whether x is an infinity with a negative sign.
19pub inline fn isNegativeInf(x: anytype) bool {
20 return x == -math.inf(@TypeOf(x));
21}
22
23test isInf {
24 inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
25 try expect(!isInf(@as(T, 0.0)));
26 try expect(!isInf(@as(T, -0.0)));
27 try expect(isInf(math.inf(T)));
28 try expect(isInf(-math.inf(T)));
29 try expect(!isInf(math.nan(T)));
30 try expect(!isInf(-math.nan(T)));
31 }
32}
33
34test isPositiveInf {
35 inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
36 try expect(!isPositiveInf(@as(T, 0.0)));
37 try expect(!isPositiveInf(@as(T, -0.0)));
38 try expect(isPositiveInf(math.inf(T)));
39 try expect(!isPositiveInf(-math.inf(T)));
40 try expect(!isInf(math.nan(T)));
41 try expect(!isInf(-math.nan(T)));
42 }
43}
44
45test isNegativeInf {
46 inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
47 try expect(!isNegativeInf(@as(T, 0.0)));
48 try expect(!isNegativeInf(@as(T, -0.0)));
49 try expect(!isNegativeInf(math.inf(T)));
50 try expect(isNegativeInf(-math.inf(T)));
51 try expect(!isInf(math.nan(T)));
52 try expect(!isInf(-math.nan(T)));
53 }
54}