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