File size: 4,099 Bytes
e36aeda | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 | // Copyright 2025 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 (
. "internal/strconv"
"math"
"testing"
)
var pow10Tests = []struct {
exp10 int
mant uint128
exp2 int
ok bool
}{
{-349, uint128{0, 0}, 0, false},
{-348, uint128{0xFA8FD5A0081C0288, 0x1732C869CD60E453}, -1156, true},
{0, uint128{0x8000000000000000, 0x0000000000000000}, 1, true},
{347, uint128{0xD13EB46469447567, 0x4B7195F2D2D1A9FB}, 1153, true},
{348, uint128{0, 0}, 0, false},
}
func TestPow10(t *testing.T) {
for _, tt := range pow10Tests {
mant, exp2, ok := pow10(tt.exp10)
if mant != tt.mant || exp2 != tt.exp2 {
t.Errorf("pow10(%d) = %#016x, %#016x, %d, %v want %#016x,%#016x, %d, %v",
tt.exp10, mant.Hi, mant.Lo, exp2, ok,
tt.mant.Hi, tt.mant.Lo, tt.exp2, tt.ok)
}
}
for p := pow10Min; p <= pow10Max; p++ {
mant, exp2, ok := pow10(p)
if !ok {
t.Errorf("pow10(%d) not ok", p)
continue
}
// Note: -64 instead of -128 because we only used mant.Hi, not all of mant.
have := math.Ldexp(float64(mant.Hi), exp2-64)
want := math.Pow(10, float64(p))
if math.Abs(have-want)/want > 0.00001 {
t.Errorf("pow10(%d) = %#016x%016x/2^128 * 2^%d = %g want ~%g", p, mant.Hi, mant.Lo, exp2, have, want)
}
}
}
func u128(hi, lo uint64) uint128 {
return uint128{Hi: hi, Lo: lo}
}
var umul192Tests = []struct {
x uint64
y uint128
hi uint64
mid uint64
lo uint64
}{
{0, u128(0, 0), 0, 0, 0},
{^uint64(0), u128(^uint64(0), ^uint64(0)), ^uint64(1), ^uint64(0), 1},
}
func TestUmul192(t *testing.T) {
for _, tt := range umul192Tests {
hi, mid, lo := Umul192(tt.x, tt.y)
if hi != tt.hi || mid != tt.mid || lo != tt.lo {
t.Errorf("umul192(%#x, {%#x,%#x}) = %#x, %#x, %#x, want %#x, %#x, %#x",
tt.x, tt.y.Hi, tt.y.Lo, hi, mid, lo, tt.hi, tt.mid, tt.lo)
}
}
}
func TestMulLog10_2(t *testing.T) {
for x := -1600; x <= +1600; x++ {
iMath := mulLog10_2(x)
fMath := int(math.Floor(float64(x) * math.Ln2 / math.Ln10))
if iMath != fMath {
t.Errorf("mulLog10_2(%d) failed: %d vs %d\n", x, iMath, fMath)
}
}
}
func TestMulLog2_10(t *testing.T) {
for x := -500; x <= +500; x++ {
iMath := mulLog2_10(x)
fMath := int(math.Floor(float64(x) * math.Ln10 / math.Ln2))
if iMath != fMath {
t.Errorf("mulLog2_10(%d) failed: %d vs %d\n", x, iMath, fMath)
}
}
}
func pow5(p int) uint64 {
x := uint64(1)
for range p {
x *= 5
}
return x
}
func TestDivisiblePow5(t *testing.T) {
for p := 1; p <= 22; p++ {
x := pow5(p)
if divisiblePow5(1, p) {
t.Errorf("divisiblePow5(1, %d) = true, want, false", p)
}
if divisiblePow5(x-1, p) {
t.Errorf("divisiblePow5(%d, %d) = true, want false", x-1, p)
}
if divisiblePow5(x+1, p) {
t.Errorf("divisiblePow5(%d, %d) = true, want false", x-1, p)
}
if divisiblePow5(x/5, p) {
t.Errorf("divisiblePow5(%d, %d) = true, want false", x/5, p)
}
if !divisiblePow5(0, p) {
t.Errorf("divisiblePow5(0, %d) = false, want true", p)
}
if !divisiblePow5(x, p) {
t.Errorf("divisiblePow5(%d, %d) = false, want true", x, p)
}
if 2*x > x && !divisiblePow5(2*x, p) {
t.Errorf("divisiblePow5(%d, %d) = false, want true", 2*x, p)
}
}
}
func TestDiv5Tab(t *testing.T) {
for p := 1; p <= 22; p++ {
m := div5Tab[p-1][0]
le := div5Tab[p-1][1]
// See comment in math.go on div5Tab.
// m needs to be multiplicative inverse of pow5(p).
if m*pow5(p) != 1 {
t.Errorf("pow5Tab[%d-1][0] = %#x, but %#x * (5**%d) = %d, want 1", p, m, m, p, m*pow5(p))
}
// le needs to be ⌊(1<<64 - 1) / 5^p⌋.
want := (1<<64 - 1) / pow5(p)
if le != want {
t.Errorf("pow5Tab[%d-1][1] = %#x, want %#x", p, le, want)
}
}
}
func TestTrimZeros(t *testing.T) {
for _, x := range []uint64{1, 2, 3, 4, 101, 123} {
want := x
for p := range 20 {
haveX, haveP := trimZeros(x)
if haveX != want || haveP != p {
t.Errorf("trimZeros(%d) = %d, %d, want %d, %d", x, haveX, haveP, want, p)
}
if x >= (1<<64-1)/10 {
break
}
x *= 10
}
}
}
|