zig/lib/std/math/isinf.zig
Andrew Kelley d29871977f remove redundant license headers from zig standard library
We already have a LICENSE file that covers the Zig Standard Library. We
no longer need to remind everyone that the license is MIT in every single
file.

Previously this was introduced to clarify the situation for a fork of
Zig that made Zig's LICENSE file harder to find, and replaced it with
their own license that required annual payments to their company.
However that fork now appears to be dead. So there is no need to
reinforce the copyright notice in every single file.
2021-08-24 12:25:09 -07:00

131 lines
4.2 KiB
Zig

const std = @import("../std.zig");
const math = std.math;
const expect = std.testing.expect;
const maxInt = std.math.maxInt;
/// Returns whether x is an infinity, ignoring sign.
pub fn isInf(x: anytype) bool {
const T = @TypeOf(x);
switch (T) {
f16 => {
const bits = @bitCast(u16, x);
return bits & 0x7FFF == 0x7C00;
},
f32 => {
const bits = @bitCast(u32, x);
return bits & 0x7FFFFFFF == 0x7F800000;
},
f64 => {
const bits = @bitCast(u64, x);
return bits & (maxInt(u64) >> 1) == (0x7FF << 52);
},
f128 => {
const bits = @bitCast(u128, x);
return bits & (maxInt(u128) >> 1) == (0x7FFF << 112);
},
else => {
@compileError("isInf not implemented for " ++ @typeName(T));
},
}
}
/// Returns whether x is an infinity with a positive sign.
pub fn isPositiveInf(x: anytype) bool {
const T = @TypeOf(x);
switch (T) {
f16 => {
return @bitCast(u16, x) == 0x7C00;
},
f32 => {
return @bitCast(u32, x) == 0x7F800000;
},
f64 => {
return @bitCast(u64, x) == 0x7FF << 52;
},
f128 => {
return @bitCast(u128, x) == 0x7FFF << 112;
},
else => {
@compileError("isPositiveInf not implemented for " ++ @typeName(T));
},
}
}
/// Returns whether x is an infinity with a negative sign.
pub fn isNegativeInf(x: anytype) bool {
const T = @TypeOf(x);
switch (T) {
f16 => {
return @bitCast(u16, x) == 0xFC00;
},
f32 => {
return @bitCast(u32, x) == 0xFF800000;
},
f64 => {
return @bitCast(u64, x) == 0xFFF << 52;
},
f128 => {
return @bitCast(u128, x) == 0xFFFF << 112;
},
else => {
@compileError("isNegativeInf not implemented for " ++ @typeName(T));
},
}
}
test "math.isInf" {
try expect(!isInf(@as(f16, 0.0)));
try expect(!isInf(@as(f16, -0.0)));
try expect(!isInf(@as(f32, 0.0)));
try expect(!isInf(@as(f32, -0.0)));
try expect(!isInf(@as(f64, 0.0)));
try expect(!isInf(@as(f64, -0.0)));
try expect(!isInf(@as(f128, 0.0)));
try expect(!isInf(@as(f128, -0.0)));
try expect(isInf(math.inf(f16)));
try expect(isInf(-math.inf(f16)));
try expect(isInf(math.inf(f32)));
try expect(isInf(-math.inf(f32)));
try expect(isInf(math.inf(f64)));
try expect(isInf(-math.inf(f64)));
try expect(isInf(math.inf(f128)));
try expect(isInf(-math.inf(f128)));
}
test "math.isPositiveInf" {
try expect(!isPositiveInf(@as(f16, 0.0)));
try expect(!isPositiveInf(@as(f16, -0.0)));
try expect(!isPositiveInf(@as(f32, 0.0)));
try expect(!isPositiveInf(@as(f32, -0.0)));
try expect(!isPositiveInf(@as(f64, 0.0)));
try expect(!isPositiveInf(@as(f64, -0.0)));
try expect(!isPositiveInf(@as(f128, 0.0)));
try expect(!isPositiveInf(@as(f128, -0.0)));
try expect(isPositiveInf(math.inf(f16)));
try expect(!isPositiveInf(-math.inf(f16)));
try expect(isPositiveInf(math.inf(f32)));
try expect(!isPositiveInf(-math.inf(f32)));
try expect(isPositiveInf(math.inf(f64)));
try expect(!isPositiveInf(-math.inf(f64)));
try expect(isPositiveInf(math.inf(f128)));
try expect(!isPositiveInf(-math.inf(f128)));
}
test "math.isNegativeInf" {
try expect(!isNegativeInf(@as(f16, 0.0)));
try expect(!isNegativeInf(@as(f16, -0.0)));
try expect(!isNegativeInf(@as(f32, 0.0)));
try expect(!isNegativeInf(@as(f32, -0.0)));
try expect(!isNegativeInf(@as(f64, 0.0)));
try expect(!isNegativeInf(@as(f64, -0.0)));
try expect(!isNegativeInf(@as(f128, 0.0)));
try expect(!isNegativeInf(@as(f128, -0.0)));
try expect(!isNegativeInf(math.inf(f16)));
try expect(isNegativeInf(-math.inf(f16)));
try expect(!isNegativeInf(math.inf(f32)));
try expect(isNegativeInf(-math.inf(f32)));
try expect(!isNegativeInf(math.inf(f64)));
try expect(isNegativeInf(-math.inf(f64)));
try expect(!isNegativeInf(math.inf(f128)));
try expect(isNegativeInf(-math.inf(f128)));
}