diff options
Diffstat (limited to 'src/strconv/atof_test.go')
| -rw-r--r-- | src/strconv/atof_test.go | 430 |
1 files changed, 430 insertions, 0 deletions
diff --git a/src/strconv/atof_test.go b/src/strconv/atof_test.go new file mode 100644 index 000000000..ba4933218 --- /dev/null +++ b/src/strconv/atof_test.go @@ -0,0 +1,430 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package strconv_test + +import ( + "math" + "math/rand" + "reflect" + . "strconv" + "strings" + "testing" + "time" +) + +type atofTest struct { + in string + out string + err error +} + +var atoftests = []atofTest{ + {"", "0", ErrSyntax}, + {"1", "1", nil}, + {"+1", "1", nil}, + {"1x", "0", ErrSyntax}, + {"1.1.", "0", ErrSyntax}, + {"1e23", "1e+23", nil}, + {"1E23", "1e+23", nil}, + {"100000000000000000000000", "1e+23", nil}, + {"1e-100", "1e-100", nil}, + {"123456700", "1.234567e+08", nil}, + {"99999999999999974834176", "9.999999999999997e+22", nil}, + {"100000000000000000000001", "1.0000000000000001e+23", nil}, + {"100000000000000008388608", "1.0000000000000001e+23", nil}, + {"100000000000000016777215", "1.0000000000000001e+23", nil}, + {"100000000000000016777216", "1.0000000000000003e+23", nil}, + {"-1", "-1", nil}, + {"-0.1", "-0.1", nil}, + {"-0", "-0", nil}, + {"1e-20", "1e-20", nil}, + {"625e-3", "0.625", nil}, + + // NaNs + {"nan", "NaN", nil}, + {"NaN", "NaN", nil}, + {"NAN", "NaN", nil}, + + // Infs + {"inf", "+Inf", nil}, + {"-Inf", "-Inf", nil}, + {"+INF", "+Inf", nil}, + {"-Infinity", "-Inf", nil}, + {"+INFINITY", "+Inf", nil}, + {"Infinity", "+Inf", nil}, + + // largest float64 + {"1.7976931348623157e308", "1.7976931348623157e+308", nil}, + {"-1.7976931348623157e308", "-1.7976931348623157e+308", nil}, + // next float64 - too large + {"1.7976931348623159e308", "+Inf", ErrRange}, + {"-1.7976931348623159e308", "-Inf", ErrRange}, + // the border is ...158079 + // borderline - okay + {"1.7976931348623158e308", "1.7976931348623157e+308", nil}, + {"-1.7976931348623158e308", "-1.7976931348623157e+308", nil}, + // borderline - too large + {"1.797693134862315808e308", "+Inf", ErrRange}, + {"-1.797693134862315808e308", "-Inf", ErrRange}, + + // a little too large + {"1e308", "1e+308", nil}, + {"2e308", "+Inf", ErrRange}, + {"1e309", "+Inf", ErrRange}, + + // way too large + {"1e310", "+Inf", ErrRange}, + {"-1e310", "-Inf", ErrRange}, + {"1e400", "+Inf", ErrRange}, + {"-1e400", "-Inf", ErrRange}, + {"1e400000", "+Inf", ErrRange}, + {"-1e400000", "-Inf", ErrRange}, + + // denormalized + {"1e-305", "1e-305", nil}, + {"1e-306", "1e-306", nil}, + {"1e-307", "1e-307", nil}, + {"1e-308", "1e-308", nil}, + {"1e-309", "1e-309", nil}, + {"1e-310", "1e-310", nil}, + {"1e-322", "1e-322", nil}, + // smallest denormal + {"5e-324", "5e-324", nil}, + {"4e-324", "5e-324", nil}, + {"3e-324", "5e-324", nil}, + // too small + {"2e-324", "0", nil}, + // way too small + {"1e-350", "0", nil}, + {"1e-400000", "0", nil}, + + // try to overflow exponent + {"1e-4294967296", "0", nil}, + {"1e+4294967296", "+Inf", ErrRange}, + {"1e-18446744073709551616", "0", nil}, + {"1e+18446744073709551616", "+Inf", ErrRange}, + + // Parse errors + {"1e", "0", ErrSyntax}, + {"1e-", "0", ErrSyntax}, + {".e-1", "0", ErrSyntax}, + {"1\x00.2", "0", ErrSyntax}, + + // http://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/ + {"2.2250738585072012e-308", "2.2250738585072014e-308", nil}, + // http://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/ + {"2.2250738585072011e-308", "2.225073858507201e-308", nil}, + + // A very large number (initially wrongly parsed by the fast algorithm). + {"4.630813248087435e+307", "4.630813248087435e+307", nil}, + + // A different kind of very large number. + {"22.222222222222222", "22.22222222222222", nil}, + {"2." + strings.Repeat("2", 4000) + "e+1", "22.22222222222222", nil}, + + // Exactly halfway between 1 and math.Nextafter(1, 2). + // Round to even (down). + {"1.00000000000000011102230246251565404236316680908203125", "1", nil}, + // Slightly lower; still round down. + {"1.00000000000000011102230246251565404236316680908203124", "1", nil}, + // Slightly higher; round up. + {"1.00000000000000011102230246251565404236316680908203126", "1.0000000000000002", nil}, + // Slightly higher, but you have to read all the way to the end. + {"1.00000000000000011102230246251565404236316680908203125" + strings.Repeat("0", 10000) + "1", "1.0000000000000002", nil}, +} + +var atof32tests = []atofTest{ + // Exactly halfway between 1 and the next float32. + // Round to even (down). + {"1.000000059604644775390625", "1", nil}, + // Slightly lower. + {"1.000000059604644775390624", "1", nil}, + // Slightly higher. + {"1.000000059604644775390626", "1.0000001", nil}, + // Slightly higher, but you have to read all the way to the end. + {"1.000000059604644775390625" + strings.Repeat("0", 10000) + "1", "1.0000001", nil}, + + // largest float32: (1<<128) * (1 - 2^-24) + {"340282346638528859811704183484516925440", "3.4028235e+38", nil}, + {"-340282346638528859811704183484516925440", "-3.4028235e+38", nil}, + // next float32 - too large + {"3.4028236e38", "+Inf", ErrRange}, + {"-3.4028236e38", "-Inf", ErrRange}, + // the border is 3.40282356779...e+38 + // borderline - okay + {"3.402823567e38", "3.4028235e+38", nil}, + {"-3.402823567e38", "-3.4028235e+38", nil}, + // borderline - too large + {"3.4028235678e38", "+Inf", ErrRange}, + {"-3.4028235678e38", "-Inf", ErrRange}, + + // Denormals: less than 2^-126 + {"1e-38", "1e-38", nil}, + {"1e-39", "1e-39", nil}, + {"1e-40", "1e-40", nil}, + {"1e-41", "1e-41", nil}, + {"1e-42", "1e-42", nil}, + {"1e-43", "1e-43", nil}, + {"1e-44", "1e-44", nil}, + {"6e-45", "6e-45", nil}, // 4p-149 = 5.6e-45 + {"5e-45", "6e-45", nil}, + // Smallest denormal + {"1e-45", "1e-45", nil}, // 1p-149 = 1.4e-45 + {"2e-45", "1e-45", nil}, + + // 2^92 = 8388608p+69 = 4951760157141521099596496896 (4.9517602e27) + // is an exact power of two that needs 8 decimal digits to be correctly + // parsed back. + // The float32 before is 16777215p+68 = 4.95175986e+27 + // The halfway is 4.951760009. A bad algorithm that thinks the previous + // float32 is 8388607p+69 will shorten incorrectly to 4.95176e+27. + {"4951760157141521099596496896", "4.9517602e+27", nil}, +} + +type atofSimpleTest struct { + x float64 + s string +} + +var ( + atofRandomTests []atofSimpleTest + benchmarksRandomBits [1024]string + benchmarksRandomNormal [1024]string +) + +func init() { + // The atof routines return NumErrors wrapping + // the error and the string. Convert the table above. + for i := range atoftests { + test := &atoftests[i] + if test.err != nil { + test.err = &NumError{"ParseFloat", test.in, test.err} + } + } + for i := range atof32tests { + test := &atof32tests[i] + if test.err != nil { + test.err = &NumError{"ParseFloat", test.in, test.err} + } + } + + // Generate random inputs for tests and benchmarks + rand.Seed(time.Now().UnixNano()) + if testing.Short() { + atofRandomTests = make([]atofSimpleTest, 100) + } else { + atofRandomTests = make([]atofSimpleTest, 10000) + } + for i := range atofRandomTests { + n := uint64(rand.Uint32())<<32 | uint64(rand.Uint32()) + x := math.Float64frombits(n) + s := FormatFloat(x, 'g', -1, 64) + atofRandomTests[i] = atofSimpleTest{x, s} + } + + for i := range benchmarksRandomBits { + bits := uint64(rand.Uint32())<<32 | uint64(rand.Uint32()) + x := math.Float64frombits(bits) + benchmarksRandomBits[i] = FormatFloat(x, 'g', -1, 64) + } + + for i := range benchmarksRandomNormal { + x := rand.NormFloat64() + benchmarksRandomNormal[i] = FormatFloat(x, 'g', -1, 64) + } +} + +func testAtof(t *testing.T, opt bool) { + oldopt := SetOptimize(opt) + for i := 0; i < len(atoftests); i++ { + test := &atoftests[i] + out, err := ParseFloat(test.in, 64) + outs := FormatFloat(out, 'g', -1, 64) + if outs != test.out || !reflect.DeepEqual(err, test.err) { + t.Errorf("ParseFloat(%v, 64) = %v, %v want %v, %v", + test.in, out, err, test.out, test.err) + } + + if float64(float32(out)) == out { + out, err := ParseFloat(test.in, 32) + out32 := float32(out) + if float64(out32) != out { + t.Errorf("ParseFloat(%v, 32) = %v, not a float32 (closest is %v)", test.in, out, float64(out32)) + continue + } + outs := FormatFloat(float64(out32), 'g', -1, 32) + if outs != test.out || !reflect.DeepEqual(err, test.err) { + t.Errorf("ParseFloat(%v, 32) = %v, %v want %v, %v # %v", + test.in, out32, err, test.out, test.err, out) + } + } + } + for _, test := range atof32tests { + out, err := ParseFloat(test.in, 32) + out32 := float32(out) + if float64(out32) != out { + t.Errorf("ParseFloat(%v, 32) = %v, not a float32 (closest is %v)", test.in, out, float64(out32)) + continue + } + outs := FormatFloat(float64(out32), 'g', -1, 32) + if outs != test.out || !reflect.DeepEqual(err, test.err) { + t.Errorf("ParseFloat(%v, 32) = %v, %v want %v, %v # %v", + test.in, out32, err, test.out, test.err, out) + } + } + SetOptimize(oldopt) +} + +func TestAtof(t *testing.T) { testAtof(t, true) } + +func TestAtofSlow(t *testing.T) { testAtof(t, false) } + +func TestAtofRandom(t *testing.T) { + for _, test := range atofRandomTests { + x, _ := ParseFloat(test.s, 64) + switch { + default: + t.Errorf("number %s badly parsed as %b (expected %b)", test.s, x, test.x) + case x == test.x: + case math.IsNaN(test.x) && math.IsNaN(x): + } + } + t.Logf("tested %d random numbers", len(atofRandomTests)) +} + +var roundTripCases = []struct { + f float64 + s string +}{ + // Issue 2917. + // This test will break the optimized conversion if the + // FPU is using 80-bit registers instead of 64-bit registers, + // usually because the operating system initialized the + // thread with 80-bit precision and the Go runtime didn't + // fix the FP control word. + {8865794286000691 << 39, "4.87402195346389e+27"}, + {8865794286000692 << 39, "4.8740219534638903e+27"}, +} + +func TestRoundTrip(t *testing.T) { + for _, tt := range roundTripCases { + old := SetOptimize(false) + s := FormatFloat(tt.f, 'g', -1, 64) + if s != tt.s { + t.Errorf("no-opt FormatFloat(%b) = %s, want %s", tt.f, s, tt.s) + } + f, err := ParseFloat(tt.s, 64) + if f != tt.f || err != nil { + t.Errorf("no-opt ParseFloat(%s) = %b, %v want %b, nil", tt.s, f, err, tt.f) + } + SetOptimize(true) + s = FormatFloat(tt.f, 'g', -1, 64) + if s != tt.s { + t.Errorf("opt FormatFloat(%b) = %s, want %s", tt.f, s, tt.s) + } + f, err = ParseFloat(tt.s, 64) + if f != tt.f || err != nil { + t.Errorf("opt ParseFloat(%s) = %b, %v want %b, nil", tt.s, f, err, tt.f) + } + SetOptimize(old) + } +} + +// TestRoundTrip32 tries a fraction of all finite positive float32 values. +func TestRoundTrip32(t *testing.T) { + step := uint32(997) + if testing.Short() { + step = 99991 + } + count := 0 + for i := uint32(0); i < 0xff<<23; i += step { + f := math.Float32frombits(i) + if i&1 == 1 { + f = -f // negative + } + s := FormatFloat(float64(f), 'g', -1, 32) + + parsed, err := ParseFloat(s, 32) + parsed32 := float32(parsed) + switch { + case err != nil: + t.Errorf("ParseFloat(%q, 32) gave error %s", s, err) + case float64(parsed32) != parsed: + t.Errorf("ParseFloat(%q, 32) = %v, not a float32 (nearest is %v)", s, parsed, parsed32) + case parsed32 != f: + t.Errorf("ParseFloat(%q, 32) = %b (expected %b)", s, parsed32, f) + } + count++ + } + t.Logf("tested %d float32's", count) +} + +func BenchmarkAtof64Decimal(b *testing.B) { + for i := 0; i < b.N; i++ { + ParseFloat("33909", 64) + } +} + +func BenchmarkAtof64Float(b *testing.B) { + for i := 0; i < b.N; i++ { + ParseFloat("339.7784", 64) + } +} + +func BenchmarkAtof64FloatExp(b *testing.B) { + for i := 0; i < b.N; i++ { + ParseFloat("-5.09e75", 64) + } +} + +func BenchmarkAtof64Big(b *testing.B) { + for i := 0; i < b.N; i++ { + ParseFloat("123456789123456789123456789", 64) + } +} + +func BenchmarkAtof64RandomBits(b *testing.B) { + for i := 0; i < b.N; i++ { + ParseFloat(benchmarksRandomBits[i%1024], 64) + } +} + +func BenchmarkAtof64RandomFloats(b *testing.B) { + for i := 0; i < b.N; i++ { + ParseFloat(benchmarksRandomNormal[i%1024], 64) + } +} + +func BenchmarkAtof32Decimal(b *testing.B) { + for i := 0; i < b.N; i++ { + ParseFloat("33909", 32) + } +} + +func BenchmarkAtof32Float(b *testing.B) { + for i := 0; i < b.N; i++ { + ParseFloat("339.778", 32) + } +} + +func BenchmarkAtof32FloatExp(b *testing.B) { + for i := 0; i < b.N; i++ { + ParseFloat("12.3456e32", 32) + } +} + +var float32strings [4096]string + +func BenchmarkAtof32Random(b *testing.B) { + n := uint32(997) + for i := range float32strings { + n = (99991*n + 42) % (0xff << 23) + float32strings[i] = FormatFloat(float64(math.Float32frombits(n)), 'g', -1, 32) + } + b.ResetTimer() + for i := 0; i < b.N; i++ { + ParseFloat(float32strings[i%4096], 32) + } +} |