42 lines
1.1 KiB
Zig
42 lines
1.1 KiB
Zig
const std = @import("../std.zig");
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const math = std.math;
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const expect = std.testing.expect;
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const maxInt = std.math.maxInt;
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/// Returns whether x is a finite value.
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pub fn isFinite(x: var) bool {
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const T = @typeOf(x);
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switch (T) {
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f16 => {
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const bits = @bitCast(u16, x);
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return bits & 0x7FFF < 0x7C00;
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},
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f32 => {
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const bits = @bitCast(u32, x);
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return bits & 0x7FFFFFFF < 0x7F800000;
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},
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f64 => {
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const bits = @bitCast(u64, x);
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return bits & (maxInt(u64) >> 1) < (0x7FF << 52);
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},
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else => {
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@compileError("isFinite not implemented for " ++ @typeName(T));
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},
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}
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}
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test "math.isFinite" {
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expect(isFinite(f16(0.0)));
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expect(isFinite(f16(-0.0)));
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expect(isFinite(f32(0.0)));
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expect(isFinite(f32(-0.0)));
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expect(isFinite(f64(0.0)));
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expect(isFinite(f64(-0.0)));
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expect(!isFinite(math.inf(f16)));
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expect(!isFinite(-math.inf(f16)));
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expect(!isFinite(math.inf(f32)));
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expect(!isFinite(-math.inf(f32)));
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expect(!isFinite(math.inf(f64)));
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expect(!isFinite(-math.inf(f64)));
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}
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