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decimal_test.go
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// Copyright 2020 Denis Bernard <[email protected]>. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package decimal
import (
"encoding"
"encoding/gob"
"fmt"
"math"
"math/big"
"math/rand"
"strconv"
"strings"
"testing"
)
func BenchmarkDecimal_dnorm(b *testing.B) {
d := dec(nil).make(1000)
for i := range d {
d[i] = Word(rand.Uint64()) % _DB
}
for i := 0; i < b.N; i++ {
d[0] = Word(rand.Uint64()) % _DB
d[len(d)-1] = Word(rand.Uint64()) % _DB
_ = uint(dnorm(d))
}
}
func BenchmarkDecimal_Sqrt(b *testing.B) {
x := new(Decimal).SetUint64(2)
z := new(Decimal).SetPrec(34)
for i := 0; i < b.N; i++ {
z.Sqrt(x)
}
}
func BenchmarkDecimal_Float(b *testing.B) {
d := new(Decimal).SetPrec(100).SetUint64(2)
d.Sqrt(d)
f := d.Float(nil)
for i := 0; i < b.N; i++ {
d.Float(f)
}
}
func TestDecimal_FMA(t *testing.T) {
x := NewDecimal(123, -2).SetPrec(3)
y := NewDecimal(227, -2).SetPrec(3)
u := NewDecimal(3, -3).SetPrec(3)
z := new(Decimal).SetPrec(3).Mul(x, y) // == 2.7921
z.Add(z, u)
if s := z.String(); s != "2.79" {
t.Fatalf("Precision 3, 2.79 + 0.003 = %s, want 2.79", s)
}
z = z.FMA(x, y, u)
if s := z.String(); s != "2.8" {
t.Fatalf("Precision 3, %v * %v + 0.003 = %s, want 2.8", x, y, s)
}
// test aliasing z and u
u.FMA(x, y, u)
if s := z.String(); s != "2.8" {
t.Fatalf("Aliasing z & u, %v * %v + 0.003 = %s, want 2.8", x, y, s)
}
}
var decimalZero Decimal
var (
// required implemented interfaces
_ fmt.Stringer = &decimalZero
_ fmt.Scanner = &decimalZero
_ fmt.Formatter = &decimalZero
_ encoding.TextMarshaler = &decimalZero
_ encoding.TextUnmarshaler = &decimalZero
_ gob.GobEncoder = &decimalZero
_ gob.GobDecoder = &decimalZero
)
// Verify that ErrNaN implements the error interface.
var _ error = ErrNaN{}
func (x *Decimal) uint64() uint64 {
u, acc := x.Uint64()
if acc != Exact {
panic(fmt.Sprintf("%s is not a uint64", x.Text('g', 10)))
}
return u
}
func (x *Decimal) int64() int64 {
i, acc := x.Int64()
if acc != Exact {
panic(fmt.Sprintf("%s is not an int64", x.Text('g', 10)))
}
return i
}
func TestDecimalZeroValue(t *testing.T) {
// zero (uninitialized) value is a ready-to-use 0.0
var x Decimal
if s := x.Text('f', 1); s != "0.0" {
t.Errorf("zero value = %s; want 0.0", s)
}
// zero value has precision 0
if prec := x.Prec(); prec != 0 {
t.Errorf("prec = %d; want 0", prec)
}
// zero value can be used in any and all positions of binary operations
make := func(x int) *Decimal {
var f Decimal
if x != 0 {
f.SetInt64(int64(x))
}
// x == 0 translates into the zero value
return &f
}
for _, test := range []struct {
z, x, y, want int
opname rune
op func(z, x, y *Decimal) *Decimal
}{
{0, 0, 0, 0, '+', (*Decimal).Add},
{0, 1, 2, 3, '+', (*Decimal).Add},
{1, 2, 0, 2, '+', (*Decimal).Add},
{2, 0, 1, 1, '+', (*Decimal).Add},
{0, 0, 0, 0, '-', (*Decimal).Sub},
{0, 1, 2, -1, '-', (*Decimal).Sub},
{1, 2, 0, 2, '-', (*Decimal).Sub},
{2, 0, 1, -1, '-', (*Decimal).Sub},
{0, 0, 0, 0, '*', (*Decimal).Mul},
{0, 1, 2, 2, '*', (*Decimal).Mul},
{1, 2, 0, 0, '*', (*Decimal).Mul},
{2, 0, 1, 0, '*', (*Decimal).Mul},
// {0, 0, 0, 0, '/', (*Decimal).Quo}, // panics
{0, 2, 1, 2, '/', (*Decimal).Quo},
{1, 2, 0, 0, '/', (*Decimal).Quo}, // = +Inf
{2, 0, 1, 0, '/', (*Decimal).Quo},
} {
z := make(test.z)
test.op(z, make(test.x), make(test.y))
got := 0
if !z.IsInf() {
got = int(z.int64())
}
if got != test.want {
t.Errorf("%d %c %d = %d; want %d", test.x, test.opname, test.y, got, test.want)
}
}
// TODO(db47h) test how precision is set for zero value results
}
func makeDecimal(s string) *Decimal {
x, _, err := ParseDecimal(s, 0, 350, ToNearestEven)
if err != nil {
panic(err)
}
return x
}
func TestDecimalSetPrec(t *testing.T) {
for _, test := range []struct {
x string
prec uint
want string
acc Accuracy
}{
// prec 0
{"0", 0, "0", Exact},
{"-0", 0, "-0", Exact},
{"-Inf", 0, "-Inf", Exact},
{"+Inf", 0, "+Inf", Exact},
{"123", 0, "0", Below},
{"-123", 0, "-0", Above},
// prec at upper limit
{"0", MaxPrec, "0", Exact},
{"-0", MaxPrec, "-0", Exact},
{"-Inf", MaxPrec, "-Inf", Exact},
{"+Inf", MaxPrec, "+Inf", Exact},
// just a few regular cases - general rounding is tested elsewhere
{"1.5", 1, "2", Above},
{"-1.5", 1, "-2", Below},
{"123", 1e6, "123", Exact},
{"-123", 1e6, "-123", Exact},
} {
x := makeDecimal(test.x).SetPrec(test.prec)
prec := test.prec
if prec > MaxPrec {
prec = MaxPrec
}
if got := x.Prec(); got != prec {
t.Errorf("%s.SetPrec(%d).Prec() == %d; want %d", test.x, test.prec, got, prec)
}
if got, acc := x.String(), x.Acc(); got != test.want || acc != test.acc {
t.Errorf("%s.SetPrec(%d) = %s (%s); want %s (%s)", test.x, test.prec, got, acc, test.want, test.acc)
}
}
}
func TestDecimalMinPrec(t *testing.T) {
const max = 30
for _, test := range []struct {
x string
want uint
}{
{"0", 0},
{"-0", 0},
{"+Inf", 0},
{"-Inf", 0},
{"1", 1},
{"9", 1},
{"999", 3},
{"123456", 6},
{"123456e-1000", 6},
{"123456e+1000", 6},
// {"0.1", max},
} {
x := makeDecimal(test.x).SetPrec(max)
if got := x.MinPrec(); got != test.want {
t.Errorf("%s.MinPrec() = %d; want %d", test.x, got, test.want)
}
}
}
func TestDecimalSign(t *testing.T) {
for _, test := range []struct {
x string
s int
}{
{"-Inf", -1},
{"-1", -1},
{"-0", 0},
{"+0", 0},
{"+1", +1},
{"+Inf", +1},
} {
x := makeDecimal(test.x)
s := x.Sign()
if s != test.s {
t.Errorf("%s.Sign() = %d; want %d", test.x, s, test.s)
}
}
}
// alike(x, y) is like x.Cmp(y) == 0 but also considers the sign of 0 (0 != -0).
func alike(x, y *Decimal) bool {
return x.Cmp(y) == 0 && x.Signbit() == y.Signbit()
}
func alike32(x, y float32) bool {
// we can ignore NaNs
return x == y && math.Signbit(float64(x)) == math.Signbit(float64(y))
}
func alike64(x, y float64) bool {
// we can ignore NaNs
return x == y && math.Signbit(x) == math.Signbit(y)
}
func TestDecimalMantExp(t *testing.T) {
for _, test := range []struct {
x string
mant string
exp int
}{
{"0", "0", 0},
{"+0", "0", 0},
{"-0", "-0", 0},
{"Inf", "+Inf", 0},
{"+Inf", "+Inf", 0},
{"-Inf", "-Inf", 0},
{"1.5", "0.15", 1},
{"1.024e3", "0.1024", 4},
{"-0.00125", "-0.125", -2},
} {
x := makeDecimal(test.x)
mant := makeDecimal(test.mant)
m := new(Decimal)
e := x.MantExp(m)
if !alike(m, mant) || e != test.exp {
t.Errorf("%s.MantExp() = %s, %d; want %s, %d", test.x, m.Text('g', 10), e, test.mant, test.exp)
}
}
}
func TestDecimalMantExpAliasing(t *testing.T) {
x := makeDecimal("0.5e10")
if e := x.MantExp(x); e != 10 {
t.Fatalf("Decimal.MantExp aliasing error: got %d; want 10", e)
}
if want := makeDecimal("0.5"); !alike(x, want) {
t.Fatalf("Decimal.MantExp aliasing error: got %s; want %s", x.Text('g', 10), want.Text('g', 10))
}
}
func TestDecimalSetMantExp(t *testing.T) {
for _, test := range []struct {
frac string
exp int
z string
}{
{"0", 0, "0"},
{"+0", 0, "0"},
{"-0", 0, "-0"},
{"Inf", 1234, "+Inf"},
{"+Inf", -1234, "+Inf"},
{"-Inf", -1234, "-Inf"},
{"0", MinExp, "0"},
{"0.01", MinExp, "+0"}, // exponent underflow
{"-0.01", MinExp, "-0"}, // exponent underflow
{"1", MaxExp, "+Inf"}, // exponent overflow
{"10", MaxExp - 1, "+Inf"}, // exponent overflow
{"1", MaxExp - 1, "1e2147483646"},
{"0.75", 1, "7.5"},
{"0.5", 4, "5000"},
{"-0.5", -2, "-0.005"},
{"32", 2, "3200"},
{"1024", -5, "0.01024"},
} {
frac := makeDecimal(test.frac)
want := makeDecimal(test.z)
var z Decimal
z.SetMantExp(frac, test.exp)
if !alike(&z, want) {
t.Errorf("SetMantExp(%s, %d) = %s; want %s", test.frac, test.exp, z.Text('g', 10), test.z)
}
// test inverse property
mant := new(Decimal)
if z.SetMantExp(mant, want.MantExp(mant)).Cmp(want) != 0 {
t.Errorf("Inverse property not satisfied: got %s; want %s", z.Text('g', 10), test.z)
}
}
}
func TestDecimalPredicates(t *testing.T) {
for _, test := range []struct {
x string
sign int
signbit, inf bool
}{
{x: "-Inf", sign: -1, signbit: true, inf: true},
{x: "-1", sign: -1, signbit: true},
{x: "-0", signbit: true},
{x: "0"},
{x: "1", sign: 1},
{x: "+Inf", sign: 1, inf: true},
} {
x := makeDecimal(test.x)
if got := x.Signbit(); got != test.signbit {
t.Errorf("(%s).Signbit() = %v; want %v", test.x, got, test.signbit)
}
if got := x.Sign(); got != test.sign {
t.Errorf("(%s).Sign() = %d; want %d", test.x, got, test.sign)
}
if got := x.IsInf(); got != test.inf {
t.Errorf("(%s).IsInf() = %v; want %v", test.x, got, test.inf)
}
}
}
func TestDecimalIsInt(t *testing.T) {
for _, test := range []string{
"0 int",
"-0 int",
"1 int",
"-1 int",
"0.5",
"1.23",
"1.23e1",
"1.23e2 int",
"0.000000001e+8",
"0.000000001e+9 int",
"1.2345e200 int",
"Inf",
"+Inf",
"-Inf",
} {
s := strings.TrimSuffix(test, " int")
want := s != test
if got := makeDecimal(s).IsInt(); got != want {
t.Errorf("%s.IsInt() == %t", s, got)
}
}
}
func testDecimalRound(t *testing.T, x, r int64, prec uint, mode RoundingMode) {
// verify test data
var ok bool
switch mode {
case ToNearestEven, ToNearestAway:
ok = true // nothing to do for now
case ToZero:
if x < 0 {
ok = r >= x
} else {
ok = r <= x
}
case AwayFromZero:
if x < 0 {
ok = r <= x
} else {
ok = r >= x
}
case ToNegativeInf:
ok = r <= x
case ToPositiveInf:
ok = r >= x
default:
panic("unreachable")
}
if !ok {
t.Fatalf("incorrect test data for prec = %d, %s: x = %d, r = %d", prec, mode, x, r)
}
// compute expected accuracy
a := Exact
switch {
case r < x:
a = Below
case r > x:
a = Above
}
// round
f := new(Decimal).SetMode(mode).SetInt64(x).SetPrec(prec)
// check result
r1 := f.int64()
p1 := f.Prec()
a1 := f.Acc()
if r1 != r || p1 != prec || a1 != a {
t.Errorf("round %d (%d digits, %s) incorrect: got %d (%d digits, %s); want %d (%d digits, %s)",
x, prec, mode,
r1, p1, a1,
r, prec, a)
return
}
// g and f should be the same
// (rounding by SetPrec after SetInt64 using default precision
// should be the same as rounding by SetInt64 after setting the
// precision)
g := new(Decimal).SetMode(mode).SetPrec(prec).SetInt64(x)
if !alike(g, f) {
t.Errorf("round %d (%d digits, %s) not symmetric: got %d and %d; want %d",
x, prec, mode,
g.int64(),
r1,
r,
)
return
}
// h and f should be the same
// (repeated rounding should be idempotent)
h := new(Decimal).SetMode(mode).SetPrec(prec).Set(f)
if !alike(h, f) {
t.Errorf("round %d (%d digits, %s) not idempotent: got %d and %d; want %d",
x, prec, mode,
h.int64(),
r1,
r,
)
return
}
}
func fromBase10(s string) int64 {
x, err := strconv.ParseInt(s, 10, 64)
if err != nil {
panic(err)
}
return x
}
// TestDecimalRound tests basic rounding.
func TestDecimalRound(t *testing.T) {
for _, test := range []struct {
prec uint
x, zero, neven, naway, away string // input, results rounded to prec bits
}{
{5, "5000", "5000", "5000", "5000", "5000"},
{5, "5005", "5005", "5005", "5005", "5005"},
{5, "5050", "5050", "5050", "5050", "5050"},
{5, "5055", "5055", "5055", "5055", "5055"},
{5, "5500", "5500", "5500", "5500", "5500"},
{5, "5505", "5505", "5505", "5505", "5505"},
{5, "5550", "5550", "5550", "5550", "5550"},
{5, "5555", "5555", "5555", "5555", "5555"},
{4, "5000", "5000", "5000", "5000", "5000"},
{4, "5005", "5005", "5005", "5005", "5005"},
{4, "5050", "5050", "5050", "5050", "5050"},
{4, "5055", "5055", "5055", "5055", "5055"},
{4, "5500", "5500", "5500", "5500", "5500"},
{4, "5505", "5505", "5505", "5505", "5505"},
{4, "5550", "5550", "5550", "5550", "5550"},
{4, "5555", "5555", "5555", "5555", "5555"},
{3, "5000", "5000", "5000", "5000", "5000"},
{3, "5005", "5000", "5000", "5010", "5010"},
{3, "5050", "5050", "5050", "5050", "5050"},
{3, "5055", "5050", "5060", "5060", "5060"},
{3, "5500", "5500", "5500", "5500", "5500"},
{3, "5505", "5500", "5500", "5510", "5510"},
{3, "5550", "5550", "5550", "5550", "5550"},
{3, "9995", "9990", "10000", "10000", "10000"},
{3, "5000005", "5000000", "5000000", "5000000", "5010000"},
{3, "5005005", "5000000", "5010000", "5010000", "5010000"},
{3, "5050005", "5050000", "5050000", "5050000", "5060000"},
{3, "5055005", "5050000", "5060000", "5060000", "5060000"},
{3, "5500005", "5500000", "5500000", "5500000", "5510000"},
{3, "5505005", "5500000", "5510000", "5510000", "5510000"},
{3, "9990005", "9990000", "9990000", "9990000", "10000000"},
{3, "9995005", "9990000", "10000000", "10000000", "10000000"},
{2, "5000", "5000", "5000", "5000", "5000"},
{2, "5005", "5000", "5000", "5000", "5100"},
{2, "5050", "5000", "5000", "5100", "5100"},
{2, "5055", "5000", "5100", "5100", "5100"},
{2, "5500", "5500", "5500", "5500", "5500"},
{2, "9905", "9900", "9900", "9900", "10000"},
{2, "9950", "9900", "10000", "10000", "10000"},
{2, "9955", "9900", "10000", "10000", "10000"},
{2, "5000005", "5000000", "5000000", "5000000", "5100000"},
{2, "5005005", "5000000", "5000000", "5000000", "5100000"},
{2, "5050005", "5000000", "5100000", "5100000", "5100000"},
{2, "5055005", "5000000", "5100000", "5100000", "5100000"},
{2, "9900005", "9900000", "9900000", "9900000", "10000000"},
{2, "9905005", "9900000", "9900000", "9900000", "10000000"},
{2, "9950005", "9900000", "10000000", "10000000", "10000000"},
{2, "9955005", "9900000", "10000000", "10000000", "10000000"},
{1, "9000", "9000", "9000", "9000", "9000"},
{1, "9005", "9000", "9000", "9000", "10000"},
{1, "9050", "9000", "9000", "9000", "10000"},
{1, "9055", "9000", "9000", "9000", "10000"},
{1, "9500", "9000", "10000", "10000", "10000"},
{1, "9505", "9000", "10000", "10000", "10000"},
{1, "9550", "9000", "10000", "10000", "10000"},
{1, "9555", "9000", "10000", "10000", "10000"},
{1, "9000005", "9000000", "9000000", "9000000", "10000000"},
{1, "9005005", "9000000", "9000000", "9000000", "10000000"},
{1, "9050005", "9000000", "9000000", "9000000", "10000000"},
{1, "9055005", "9000000", "9000000", "9000000", "10000000"},
{1, "9500005", "9000000", "10000000", "10000000", "10000000"},
{1, "9505005", "9000000", "10000000", "10000000", "10000000"},
{1, "9550005", "9000000", "10000000", "10000000", "10000000"},
{1, "9555005", "9000000", "10000000", "10000000", "10000000"},
} {
x := fromBase10(test.x)
z := fromBase10(test.zero)
e := fromBase10(test.neven)
n := fromBase10(test.naway)
a := fromBase10(test.away)
prec := test.prec
testDecimalRound(t, x, z, prec, ToZero)
testDecimalRound(t, x, e, prec, ToNearestEven)
testDecimalRound(t, x, n, prec, ToNearestAway)
testDecimalRound(t, x, a, prec, AwayFromZero)
testDecimalRound(t, x, z, prec, ToNegativeInf)
testDecimalRound(t, x, a, prec, ToPositiveInf)
testDecimalRound(t, -x, -a, prec, ToNegativeInf)
testDecimalRound(t, -x, -z, prec, ToPositiveInf)
}
}
// TestFloatRound24 tests that rounding a float64 to 24 bits
// matches IEEE-754 rounding to nearest when converting a
// float64 to a float32 (excluding denormal numbers).
// TODO(db47h): implement this for decimal64/128
// func TestFloatRound24(t *testing.T) {
// const x0 = 1<<26 - 0x10 // 11...110000 (26 bits)
// for d := 0; d <= 0x10; d++ {
// x := float64(x0 + d)
// f := new(Float).SetPrec(24).SetFloat64(x)
// got, _ := f.Float32()
// want := float32(x)
// if got != want {
// t.Errorf("Round(%g, 24) = %g; want %g", x, got, want)
// }
// }
// }
func TestDecimalSetUint64(t *testing.T) {
for _, want := range []uint64{
0,
1,
2,
10,
100,
1<<32 - 1,
1 << 32,
1<<64 - 1,
} {
var f Decimal
f.SetUint64(want)
if got := f.uint64(); got != want {
t.Errorf("got %#x (%s); want %#x", got, f.Text('p', 0), want)
}
}
// test basic rounding behavior (exhaustive rounding testing is done elsewhere)
const x uint64 = 0x8765432187654321 // 64 bits needed
mp := decDigits64(uint64(x))
for prec := uint(1); prec <= mp; prec++ {
f := new(Decimal).SetPrec(prec).SetMode(ToZero).SetUint64(x)
got := f.uint64()
want := x - x%uint64(pow10(mp-prec)) // cut off (round to zero) low prec digits
if got != want {
t.Errorf("got %#x (%s); want %#x", got, f.Text('p', 0), want)
}
}
}
func TestDecimalSetInt64(t *testing.T) {
for _, want := range []int64{
0,
1,
2,
10,
100,
1<<32 - 1,
1 << 32,
1<<63 - 1,
} {
for i := range [2]int{} {
if i&1 != 0 {
want = -want
}
var f Decimal
f.SetInt64(want)
if got := f.int64(); got != want {
t.Errorf("got %#x (%s); want %#x", got, f.Text('p', 0), want)
}
}
}
// test basic rounding behavior (exhaustive rounding testing is done elsewhere)
const x int64 = 0x7654321076543210 // 63 bits needed
mp := decDigits64(uint64(x))
for prec := uint(1); prec <= mp; prec++ {
f := new(Decimal).SetPrec(prec).SetMode(ToZero).SetInt64(x)
got := f.int64()
want := x - x%int64(pow10(mp-prec)) // cut off (round to zero) low prec digits
if got != want {
t.Errorf("got %#x (%s); want %#x", got, f.Text('p', 0), want)
}
}
}
func TestDecimalSetFloat64(t *testing.T) {
for _, want := range []float64{
0,
1,
2,
12345,
1e10,
1e100,
3.14159265e10,
2.718281828e-123,
1.0 / 3,
1.1,
math.MaxFloat32,
math.MaxFloat64,
math.SmallestNonzeroFloat32,
math.SmallestNonzeroFloat64,
math.Inf(-1),
math.Inf(0),
-math.Inf(1),
} {
for i := range [2]int{} {
if i&1 != 0 {
want = -want
}
var f Decimal
f.SetFloat64(want)
if got, _ := f.Float64(); got != want {
t.Errorf("got %g (%s); want %g", got, f.Text('p', 0), want)
}
}
}
// test NaN
defer func() {
if p, ok := recover().(ErrNaN); !ok {
t.Errorf("got %v; want ErrNaN panic", p)
}
}()
var f Decimal
f.SetFloat64(math.NaN())
// should not reach here
t.Errorf("got %s; want ErrNaN panic", f.Text('p', 0))
}
func TestDecimalSetInt(t *testing.T) {
for _, want := range []string{
"0",
"1",
"-1",
"1234567890",
"123456789012345678901234567890",
"123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890",
} {
var x big.Int
_, ok := x.SetString(want, 0)
if !ok {
t.Errorf("invalid integer %s", want)
continue
}
var f Decimal
f.SetInt(&x)
// check precision
n := len(strings.TrimRight(want, "0"))
if n < DefaultDecimalPrec {
n = DefaultDecimalPrec
}
if prec := f.Prec(); prec != uint(n) {
t.Errorf("%s: got prec = %d; want %d", want, prec, n)
}
// check value
got := f.Text('g', 100)
if got != want {
t.Errorf("got %s (%s); want %s", got, f.Text('p', 0), want)
}
}
}
func TestDecimalSetRat(t *testing.T) {
for _, want := range []struct {
v string
p uint
}{
{"0", DefaultDecimalPrec},
{"1", DefaultDecimalPrec},
{"-1", DefaultDecimalPrec},
{"1234567890", DefaultDecimalPrec},
{"123456789012345678901234567890", DefaultDecimalPrec},
{"123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890", 89},
{"1.2", DefaultDecimalPrec},
{"3.14159265", DefaultDecimalPrec},
// TODO(db47h) expand
} {
var x big.Rat
_, ok := x.SetString(want.v)
if !ok {
t.Errorf("invalid fraction %s", want.v)
continue
}
var f1, f2 Decimal
f2.SetPrec(1000)
f1.SetRat(&x)
f2.SetRat(&x)
// check precision when set automatically
if want.p < DefaultDecimalPrec {
want.p = DefaultDecimalPrec
}
if prec := f1.Prec(); prec != want.p {
t.Errorf("got prec = %d; want %d", prec, want.p)
}
got := f2.Text('g', 100)
if got != want.v {
t.Errorf("got %s (%s); want %s", got, f2.Text('p', 0), want.v)
}
}
}
func TestFloatSetInf(t *testing.T) {
var f Decimal
for _, test := range []struct {
signbit bool
prec uint
want string
}{
{false, 0, "+Inf"},
{true, 0, "-Inf"},
{false, 10, "+Inf"},
{true, 30, "-Inf"},
} {
x := f.SetPrec(test.prec).SetInf(test.signbit)
if got := x.String(); got != test.want || x.Prec() != test.prec {
t.Errorf("SetInf(%v) = %s (prec = %d); want %s (prec = %d)", test.signbit, got, x.Prec(), test.want, test.prec)
}
}
}
func TestDecimalUint64(t *testing.T) {
for _, test := range []struct {
x string
out uint64
acc Accuracy
}{
{"-Inf", 0, Above},
{"-1", 0, Above},
{"-1e-1000", 0, Above},
{"-0", 0, Exact},
{"0", 0, Exact},
{"1e-1000", 0, Below},
{"1", 1, Exact},
{"1.000000000000000000001", 1, Below},
{"12345.0", 12345, Exact},
{"12345.000000000000000000001", 12345, Below},
{"18446744073709551615", 18446744073709551615, Exact},
{"18446744073709551615.000000000000000000001", math.MaxUint64, Below},
{"18446744073709551616", math.MaxUint64, Below},
{"1e10000", math.MaxUint64, Below},
{"+Inf", math.MaxUint64, Below},
} {
x := makeDecimal(test.x)
out, acc := x.Uint64()
if out != test.out || acc != test.acc {
t.Errorf("%s: got %d (%s); want %d (%s)", test.x, out, acc, test.out, test.acc)
}
}
}
func TestDecimalInt64(t *testing.T) {
for _, test := range []struct {
x string
out int64
acc Accuracy
}{
{"-Inf", math.MinInt64, Above},
{"-1e10000", math.MinInt64, Above},
{"-9223372036854775809", math.MinInt64, Above},
{"-9223372036854775808.000000000000000000001", math.MinInt64, Above},
{"-9223372036854775808", -9223372036854775808, Exact},
{"-9223372036854775807.000000000000000000001", -9223372036854775807, Above},
{"-9223372036854775807", -9223372036854775807, Exact},
{"-12345.000000000000000000001", -12345, Above},
{"-12345.0", -12345, Exact},
{"-1.000000000000000000001", -1, Above},
{"-1.5", -1, Above},
{"-1", -1, Exact},
{"-1e-1000", 0, Above},
{"0", 0, Exact},
{"1e-1000", 0, Below},
{"1", 1, Exact},
{"1.000000000000000000001", 1, Below},
{"1.5", 1, Below},
{"12345.0", 12345, Exact},
{"12345.000000000000000000001", 12345, Below},
{"9223372036854775807", 9223372036854775807, Exact},
{"9223372036854775807.000000000000000000001", math.MaxInt64, Below},
{"9223372036854775808", math.MaxInt64, Below},
{"1e10000", math.MaxInt64, Below},
{"+Inf", math.MaxInt64, Below},
} {
x := makeDecimal(test.x)
out, acc := x.Int64()
if out != test.out || acc != test.acc {
t.Errorf("%s: got %d (%s); want %d (%s)", test.x, out, acc, test.out, test.acc)
}
}
}
func TestDecimalFloat32(t *testing.T) {
for _, test := range []struct {
x string
out float32
acc Accuracy
}{
{"0", 0, Exact},
// underflow to zero
{"1e-1000", 0, Below},
{"0x0.000002p-127", 0, Below},
{"0x.0000010p-126", 0, Below},
// denormals
{"1.401298464e-45", math.SmallestNonzeroFloat32, Above}, // rounded up to smallest denormal
{"0x.ffffff8p-149", math.SmallestNonzeroFloat32, Above}, // rounded up to smallest denormal
{"0x.0000018p-126", math.SmallestNonzeroFloat32, Above}, // rounded up to smallest denormal
{"0x.0000020p-126", math.SmallestNonzeroFloat32, Exact},
{"0x.8p-148", math.SmallestNonzeroFloat32, Exact},
{"1p-149", math.SmallestNonzeroFloat32, Exact},
{"0x.fffffep-126", math.Float32frombits(0x7fffff), Exact}, // largest denormal
// special denormal cases (see issues 14553, 14651)
{"0x0.0000001p-126", math.Float32frombits(0x00000000), Below}, // underflow to zero
{"0x0.0000008p-126", math.Float32frombits(0x00000000), Below}, // underflow to zero
{"0x0.0000010p-126", math.Float32frombits(0x00000000), Below}, // rounded down to even
{"0x0.0000011p-126", math.Float32frombits(0x00000001), Above}, // rounded up to smallest denormal
{"0x0.0000018p-126", math.Float32frombits(0x00000001), Above}, // rounded up to smallest denormal
{"0x1.0000000p-149", math.Float32frombits(0x00000001), Exact}, // smallest denormal
{"0x0.0000020p-126", math.Float32frombits(0x00000001), Exact}, // smallest denormal
{"0x0.fffffe0p-126", math.Float32frombits(0x007fffff), Exact}, // largest denormal
{"0x1.0000000p-126", math.Float32frombits(0x00800000), Exact}, // smallest normal
{"0x0.8p-149", math.Float32frombits(0x000000000), Below}, // rounded down to even
{"0x0.9p-149", math.Float32frombits(0x000000001), Above}, // rounded up to smallest denormal
{"0x0.ap-149", math.Float32frombits(0x000000001), Above}, // rounded up to smallest denormal
{"0x0.bp-149", math.Float32frombits(0x000000001), Above}, // rounded up to smallest denormal
{"0x0.cp-149", math.Float32frombits(0x000000001), Above}, // rounded up to smallest denormal
{"0x1.0p-149", math.Float32frombits(0x000000001), Exact}, // smallest denormal
{"0x1.7p-149", math.Float32frombits(0x000000001), Below},
{"0x1.8p-149", math.Float32frombits(0x000000002), Above},
{"0x1.9p-149", math.Float32frombits(0x000000002), Above},
{"0x2.0p-149", math.Float32frombits(0x000000002), Exact},
{"0x2.8p-149", math.Float32frombits(0x000000002), Below}, // rounded down to even
{"0x2.9p-149", math.Float32frombits(0x000000003), Above},
{"0x3.0p-149", math.Float32frombits(0x000000003), Exact},
{"0x3.7p-149", math.Float32frombits(0x000000003), Below},
{"0x3.8p-149", math.Float32frombits(0x000000004), Above}, // rounded up to even
{"0x4.0p-149", math.Float32frombits(0x000000004), Exact},
{"0x4.8p-149", math.Float32frombits(0x000000004), Below}, // rounded down to even
{"0x4.9p-149", math.Float32frombits(0x000000005), Above},
// specific case from issue 14553
{"0x7.7p-149", math.Float32frombits(0x000000007), Below},
{"0x7.8p-149", math.Float32frombits(0x000000008), Above},
{"0x7.9p-149", math.Float32frombits(0x000000008), Above},
// normals
{"0x.ffffffp-126", math.Float32frombits(0x00800000), Above}, // rounded up to smallest normal
{"1p-126", math.Float32frombits(0x00800000), Exact}, // smallest normal
{"0x1.fffffep-126", math.Float32frombits(0x00ffffff), Exact},
{"0x1.ffffffp-126", math.Float32frombits(0x01000000), Above}, // rounded up
{"1", 1, Exact},
{"1.000000000000000000001", 1, Below},
{"12345.0", 12345, Exact},
{"12345.000000000000000000001", 12345, Below},
{"0x1.fffffe0p127", math.MaxFloat32, Exact},
{"0x1.fffffe8p127", math.MaxFloat32, Below},
// overflow
{"0x1.ffffff0p127", float32(math.Inf(+1)), Above},
{"0x1p128", float32(math.Inf(+1)), Above},
{"1e10000", float32(math.Inf(+1)), Above},
{"0x1.ffffff0p2147483646", float32(math.Inf(+1)), Above}, // overflow in rounding
// inf
{"Inf", float32(math.Inf(+1)), Exact},
} {
for i := 0; i < 2; i++ {
// test both signs
tx, tout, tacc := test.x, test.out, test.acc
if i != 0 {
tx = "-" + tx
tout = -tout
tacc = -tacc
}
// conversion should match strconv where syntax is agreeable
if f, err := strconv.ParseFloat(tx, 32); err == nil && !alike32(float32(f), tout) {
t.Errorf("%s: got %g; want %g (incorrect test data)", tx, f, tout)
}
x := makeDecimal(tx)
out, acc := x.Float32()
// TODO(db47h): need to check accuracy, somehow.
if !alike32(out, tout) /* || acc != tacc */ { // do not check accuracy
t.Errorf("%s: got %g (%#08x, %s); want %g (%#08x, %s)", tx, out, math.Float32bits(out), acc, test.out, math.Float32bits(test.out), tacc)
}
// test that x.SetFloat64(float64(f)).Float32() == f
var x2 Decimal
out2, acc2 := x2.SetFloat64(float64(out)).Float32()
if !alike32(out2, out) /* || acc2 != Exact */ {
t.Errorf("idempotency test: got %g (%s); want %g (Exact)", out2, acc2, out)
}
}
}
}
func TestDecimalFloat64(t *testing.T) {
const smallestNormalFloat64 = 2.2250738585072014e-308 // 1p-1022
for _, test := range []struct {
x string
out float64
acc Accuracy
}{
{"0", 0, Exact},