zig/std/math/isinf.zig
2018-10-26 15:01:51 -04:00

107 lines
2.9 KiB
Zig

const std = @import("../index.zig");
const math = std.math;
const assert = std.debug.assert;
const maxInt = std.math.maxInt;
pub fn isInf(x: var) 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);
},
else => {
@compileError("isInf not implemented for " ++ @typeName(T));
},
}
}
pub fn isPositiveInf(x: var) 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;
},
else => {
@compileError("isPositiveInf not implemented for " ++ @typeName(T));
},
}
}
pub fn isNegativeInf(x: var) 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;
},
else => {
@compileError("isNegativeInf not implemented for " ++ @typeName(T));
},
}
}
test "math.isInf" {
assert(!isInf(f16(0.0)));
assert(!isInf(f16(-0.0)));
assert(!isInf(f32(0.0)));
assert(!isInf(f32(-0.0)));
assert(!isInf(f64(0.0)));
assert(!isInf(f64(-0.0)));
assert(isInf(math.inf(f16)));
assert(isInf(-math.inf(f16)));
assert(isInf(math.inf(f32)));
assert(isInf(-math.inf(f32)));
assert(isInf(math.inf(f64)));
assert(isInf(-math.inf(f64)));
}
test "math.isPositiveInf" {
assert(!isPositiveInf(f16(0.0)));
assert(!isPositiveInf(f16(-0.0)));
assert(!isPositiveInf(f32(0.0)));
assert(!isPositiveInf(f32(-0.0)));
assert(!isPositiveInf(f64(0.0)));
assert(!isPositiveInf(f64(-0.0)));
assert(isPositiveInf(math.inf(f16)));
assert(!isPositiveInf(-math.inf(f16)));
assert(isPositiveInf(math.inf(f32)));
assert(!isPositiveInf(-math.inf(f32)));
assert(isPositiveInf(math.inf(f64)));
assert(!isPositiveInf(-math.inf(f64)));
}
test "math.isNegativeInf" {
assert(!isNegativeInf(f16(0.0)));
assert(!isNegativeInf(f16(-0.0)));
assert(!isNegativeInf(f32(0.0)));
assert(!isNegativeInf(f32(-0.0)));
assert(!isNegativeInf(f64(0.0)));
assert(!isNegativeInf(f64(-0.0)));
assert(!isNegativeInf(math.inf(f16)));
assert(isNegativeInf(-math.inf(f16)));
assert(!isNegativeInf(math.inf(f32)));
assert(isNegativeInf(-math.inf(f32)));
assert(!isNegativeInf(math.inf(f64)));
assert(isNegativeInf(-math.inf(f64)));
}