265 lines
7.3 KiB
Go
265 lines
7.3 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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. "strconv"
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"testing"
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)
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type ftoaTest struct {
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f float64
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fmt byte
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prec int
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s string
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}
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func fdiv(a, b float64) float64 { return a / b }
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const (
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below1e23 = 99999999999999974834176
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above1e23 = 100000000000000008388608
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)
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var ftoatests = []ftoaTest{
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{1, 'e', 5, "1.00000e+00"},
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{1, 'f', 5, "1.00000"},
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{1, 'g', 5, "1"},
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{1, 'g', -1, "1"},
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{1, 'x', -1, "0x1p+00"},
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{1, 'x', 5, "0x1.00000p+00"},
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{20, 'g', -1, "20"},
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{20, 'x', -1, "0x1.4p+04"},
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{1234567.8, 'g', -1, "1.2345678e+06"},
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{1234567.8, 'x', -1, "0x1.2d687cccccccdp+20"},
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{200000, 'g', -1, "200000"},
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{200000, 'x', -1, "0x1.86ap+17"},
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{200000, 'X', -1, "0X1.86AP+17"},
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{2000000, 'g', -1, "2e+06"},
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// g conversion and zero suppression
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{400, 'g', 2, "4e+02"},
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{40, 'g', 2, "40"},
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{4, 'g', 2, "4"},
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{.4, 'g', 2, "0.4"},
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{.04, 'g', 2, "0.04"},
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{.004, 'g', 2, "0.004"},
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{.0004, 'g', 2, "0.0004"},
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{.00004, 'g', 2, "4e-05"},
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{.000004, 'g', 2, "4e-06"},
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{0, 'e', 5, "0.00000e+00"},
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{0, 'f', 5, "0.00000"},
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{0, 'g', 5, "0"},
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{0, 'g', -1, "0"},
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{0, 'x', 5, "0x0.00000p+00"},
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{-1, 'e', 5, "-1.00000e+00"},
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{-1, 'f', 5, "-1.00000"},
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{-1, 'g', 5, "-1"},
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{-1, 'g', -1, "-1"},
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{12, 'e', 5, "1.20000e+01"},
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{12, 'f', 5, "12.00000"},
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{12, 'g', 5, "12"},
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{12, 'g', -1, "12"},
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{123456700, 'e', 5, "1.23457e+08"},
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{123456700, 'f', 5, "123456700.00000"},
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{123456700, 'g', 5, "1.2346e+08"},
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{123456700, 'g', -1, "1.234567e+08"},
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{1.2345e6, 'e', 5, "1.23450e+06"},
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{1.2345e6, 'f', 5, "1234500.00000"},
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{1.2345e6, 'g', 5, "1.2345e+06"},
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{1e23, 'e', 17, "9.99999999999999916e+22"},
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{1e23, 'f', 17, "99999999999999991611392.00000000000000000"},
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{1e23, 'g', 17, "9.9999999999999992e+22"},
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{1e23, 'e', -1, "1e+23"},
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{1e23, 'f', -1, "100000000000000000000000"},
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{1e23, 'g', -1, "1e+23"},
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{below1e23, 'e', 17, "9.99999999999999748e+22"},
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{below1e23, 'f', 17, "99999999999999974834176.00000000000000000"},
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{below1e23, 'g', 17, "9.9999999999999975e+22"},
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{below1e23, 'e', -1, "9.999999999999997e+22"},
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{below1e23, 'f', -1, "99999999999999970000000"},
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{below1e23, 'g', -1, "9.999999999999997e+22"},
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{above1e23, 'e', 17, "1.00000000000000008e+23"},
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{above1e23, 'f', 17, "100000000000000008388608.00000000000000000"},
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{above1e23, 'g', 17, "1.0000000000000001e+23"},
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{above1e23, 'e', -1, "1.0000000000000001e+23"},
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{above1e23, 'f', -1, "100000000000000010000000"},
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{above1e23, 'g', -1, "1.0000000000000001e+23"},
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{fdiv(5e-304, 1e20), 'g', -1, "5e-324"}, // avoid constant arithmetic
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{fdiv(-5e-304, 1e20), 'g', -1, "-5e-324"}, // avoid constant arithmetic
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{32, 'g', -1, "32"},
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{32, 'g', 0, "3e+01"},
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{100, 'x', -1, "0x1.9p+06"},
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{100, 'y', -1, "%y"},
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{math.NaN(), 'g', -1, "NaN"},
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{-math.NaN(), 'g', -1, "NaN"},
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{math.Inf(0), 'g', -1, "+Inf"},
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{math.Inf(-1), 'g', -1, "-Inf"},
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{-math.Inf(0), 'g', -1, "-Inf"},
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{-1, 'b', -1, "-4503599627370496p-52"},
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// fixed bugs
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{0.9, 'f', 1, "0.9"},
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{0.09, 'f', 1, "0.1"},
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{0.0999, 'f', 1, "0.1"},
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{0.05, 'f', 1, "0.1"},
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{0.05, 'f', 0, "0"},
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{0.5, 'f', 1, "0.5"},
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{0.5, 'f', 0, "0"},
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{1.5, 'f', 0, "2"},
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// https://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/
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{2.2250738585072012e-308, 'g', -1, "2.2250738585072014e-308"},
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// https://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/
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{2.2250738585072011e-308, 'g', -1, "2.225073858507201e-308"},
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// Issue 2625.
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{383260575764816448, 'f', 0, "383260575764816448"},
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{383260575764816448, 'g', -1, "3.8326057576481645e+17"},
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// Issue 29491.
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{498484681984085570, 'f', -1, "498484681984085570"},
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{-5.8339553793802237e+23, 'g', -1, "-5.8339553793802237e+23"},
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// rounding
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{2.275555555555555, 'x', -1, "0x1.23456789abcdep+01"},
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{2.275555555555555, 'x', 0, "0x1p+01"},
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{2.275555555555555, 'x', 2, "0x1.23p+01"},
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{2.275555555555555, 'x', 16, "0x1.23456789abcde000p+01"},
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{2.275555555555555, 'x', 21, "0x1.23456789abcde00000000p+01"},
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{2.2755555510520935, 'x', -1, "0x1.2345678p+01"},
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{2.2755555510520935, 'x', 6, "0x1.234568p+01"},
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{2.275555431842804, 'x', -1, "0x1.2345668p+01"},
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{2.275555431842804, 'x', 6, "0x1.234566p+01"},
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{3.999969482421875, 'x', -1, "0x1.ffffp+01"},
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{3.999969482421875, 'x', 4, "0x1.ffffp+01"},
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{3.999969482421875, 'x', 3, "0x1.000p+02"},
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{3.999969482421875, 'x', 2, "0x1.00p+02"},
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{3.999969482421875, 'x', 1, "0x1.0p+02"},
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{3.999969482421875, 'x', 0, "0x1p+02"},
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}
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func TestFtoa(t *testing.T) {
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for i := 0; i < len(ftoatests); i++ {
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test := &ftoatests[i]
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s := FormatFloat(test.f, test.fmt, test.prec, 64)
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if s != test.s {
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t.Error("testN=64", test.f, string(test.fmt), test.prec, "want", test.s, "got", s)
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}
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x := AppendFloat([]byte("abc"), test.f, test.fmt, test.prec, 64)
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if string(x) != "abc"+test.s {
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t.Error("AppendFloat testN=64", test.f, string(test.fmt), test.prec, "want", "abc"+test.s, "got", string(x))
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}
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if float64(float32(test.f)) == test.f && test.fmt != 'b' {
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s := FormatFloat(test.f, test.fmt, test.prec, 32)
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if s != test.s {
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t.Error("testN=32", test.f, string(test.fmt), test.prec, "want", test.s, "got", s)
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}
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x := AppendFloat([]byte("abc"), test.f, test.fmt, test.prec, 32)
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if string(x) != "abc"+test.s {
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t.Error("AppendFloat testN=32", test.f, string(test.fmt), test.prec, "want", "abc"+test.s, "got", string(x))
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}
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}
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}
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}
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func TestFtoaRandom(t *testing.T) {
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N := int(1e4)
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if testing.Short() {
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N = 100
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}
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t.Logf("testing %d random numbers with fast and slow FormatFloat", N)
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for i := 0; i < N; i++ {
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bits := uint64(rand.Uint32())<<32 | uint64(rand.Uint32())
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x := math.Float64frombits(bits)
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shortFast := FormatFloat(x, 'g', -1, 64)
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SetOptimize(false)
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shortSlow := FormatFloat(x, 'g', -1, 64)
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SetOptimize(true)
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if shortSlow != shortFast {
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t.Errorf("%b printed as %s, want %s", x, shortFast, shortSlow)
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}
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prec := rand.Intn(12) + 5
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shortFast = FormatFloat(x, 'e', prec, 64)
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SetOptimize(false)
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shortSlow = FormatFloat(x, 'e', prec, 64)
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SetOptimize(true)
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if shortSlow != shortFast {
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t.Errorf("%b printed as %s, want %s", x, shortFast, shortSlow)
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}
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}
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}
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var ftoaBenches = []struct {
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name string
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float float64
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fmt byte
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prec int
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bitSize int
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}{
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{"Decimal", 33909, 'g', -1, 64},
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{"Float", 339.7784, 'g', -1, 64},
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{"Exp", -5.09e75, 'g', -1, 64},
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{"NegExp", -5.11e-95, 'g', -1, 64},
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{"Big", 123456789123456789123456789, 'g', -1, 64},
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{"BinaryExp", -1, 'b', -1, 64},
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{"32Integer", 33909, 'g', -1, 32},
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{"32ExactFraction", 3.375, 'g', -1, 32},
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{"32Point", 339.7784, 'g', -1, 32},
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{"32Exp", -5.09e25, 'g', -1, 32},
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{"32NegExp", -5.11e-25, 'g', -1, 32},
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{"64Fixed1", 123456, 'e', 3, 64},
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{"64Fixed2", 123.456, 'e', 3, 64},
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{"64Fixed3", 1.23456e+78, 'e', 3, 64},
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{"64Fixed4", 1.23456e-78, 'e', 3, 64},
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// Trigger slow path (see issue #15672).
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{"Slowpath64", 622666234635.3213e-320, 'e', -1, 64},
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}
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func BenchmarkFormatFloat(b *testing.B) {
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for _, c := range ftoaBenches {
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b.Run(c.name, func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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FormatFloat(c.float, c.fmt, c.prec, c.bitSize)
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}
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})
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}
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}
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func BenchmarkAppendFloat(b *testing.B) {
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dst := make([]byte, 30)
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for _, c := range ftoaBenches {
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b.Run(c.name, func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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AppendFloat(dst[:0], c.float, c.fmt, c.prec, c.bitSize)
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}
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})
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}
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}
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