2019-03-03 05:46:04 +08:00
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const std = @import("../std.zig");
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2017-12-24 11:08:53 +08:00
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const math = std.math;
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2019-02-09 07:18:47 +08:00
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const expect = std.testing.expect;
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2018-10-27 02:59:58 +08:00
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const maxInt = std.math.maxInt;
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2017-06-16 16:26:10 +08:00
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2018-01-25 17:10:11 +08:00
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pub fn isFinite(x: var) bool {
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2017-06-16 16:26:10 +08:00
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const T = @typeOf(x);
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switch (T) {
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2018-06-30 07:44:54 +08:00
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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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2017-06-16 16:26:10 +08:00
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f32 => {
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const bits = @bitCast(u32, x);
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2017-12-22 13:50:30 +08:00
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return bits & 0x7FFFFFFF < 0x7F800000;
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2017-06-16 16:26:10 +08:00
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},
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f64 => {
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const bits = @bitCast(u64, x);
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2018-10-27 02:59:58 +08:00
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return bits & (maxInt(u64) >> 1) < (0x7FF << 52);
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2017-06-16 16:26:10 +08:00
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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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2017-06-20 02:36:33 +08:00
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test "math.isFinite" {
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2019-02-09 07:18:47 +08:00
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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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2017-06-16 16:26:10 +08:00
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}
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