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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)));
}
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