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add dec package as new dep

pull/6/head
Daniel Smith 2014-12-29 15:55:25 -08:00
parent 83f1aa5546
commit 9b8c5d0876
11 changed files with 1726 additions and 0 deletions
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4
Godeps/Godeps.json generated
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@ -203,6 +203,10 @@
{
"ImportPath": "gopkg.in/v2/yaml",
"Rev": "d466437aa4adc35830964cffc5b5f262c63ddcb4"
},
{
"ImportPath": "speter.net/go/exp/math/dec/inf",
"Rev": "42ca6cd68aa922bc3f32f1e056e61b65945d9ad7"
}
]
}

57
Godeps/_workspace/src/speter.net/go/exp/math/dec/inf/LICENSE generated vendored Normal file
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@ -0,0 +1,57 @@
Copyright (c) 2012 Péter Surányi. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
----------------------------------------------------------------------
Portions of inf.Dec's source code have been derived from Go and are
covered by the following license:
----------------------------------------------------------------------
Copyright (c) 2009 The Go Authors. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
* Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

210
Godeps/_workspace/src/speter.net/go/exp/math/dec/inf/benchmark_test.go generated vendored Normal file
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package inf
import (
"fmt"
"math/big"
"math/rand"
"sync"
"testing"
)
const maxcap = 1024 * 1024
const bits = 256
const maxscale = 32
var once sync.Once
var decInput [][2]Dec
var intInput [][2]big.Int
var initBench = func() {
decInput = make([][2]Dec, maxcap)
intInput = make([][2]big.Int, maxcap)
max := new(big.Int).Lsh(big.NewInt(1), bits)
r := rand.New(rand.NewSource(0))
for i := 0; i < cap(decInput); i++ {
decInput[i][0].SetUnscaledBig(new(big.Int).Rand(r, max)).
SetScale(Scale(r.Int31n(int32(2*maxscale-1)) - int32(maxscale)))
decInput[i][1].SetUnscaledBig(new(big.Int).Rand(r, max)).
SetScale(Scale(r.Int31n(int32(2*maxscale-1)) - int32(maxscale)))
}
for i := 0; i < cap(intInput); i++ {
intInput[i][0].Rand(r, max)
intInput[i][1].Rand(r, max)
}
}
func doBenchmarkDec1(b *testing.B, f func(z *Dec)) {
once.Do(initBench)
b.ResetTimer()
b.StartTimer()
for i := 0; i < b.N; i++ {
f(&decInput[i%maxcap][0])
}
}
func doBenchmarkDec2(b *testing.B, f func(x, y *Dec)) {
once.Do(initBench)
b.ResetTimer()
b.StartTimer()
for i := 0; i < b.N; i++ {
f(&decInput[i%maxcap][0], &decInput[i%maxcap][1])
}
}
func doBenchmarkInt1(b *testing.B, f func(z *big.Int)) {
once.Do(initBench)
b.ResetTimer()
b.StartTimer()
for i := 0; i < b.N; i++ {
f(&intInput[i%maxcap][0])
}
}
func doBenchmarkInt2(b *testing.B, f func(x, y *big.Int)) {
once.Do(initBench)
b.ResetTimer()
b.StartTimer()
for i := 0; i < b.N; i++ {
f(&intInput[i%maxcap][0], &intInput[i%maxcap][1])
}
}
func Benchmark_Dec_String(b *testing.B) {
doBenchmarkDec1(b, func(x *Dec) {
x.String()
})
}
func Benchmark_Dec_StringScan(b *testing.B) {
doBenchmarkDec1(b, func(x *Dec) {
s := x.String()
d := new(Dec)
fmt.Sscan(s, d)
})
}
func Benchmark_Dec_GobEncode(b *testing.B) {
doBenchmarkDec1(b, func(x *Dec) {
x.GobEncode()
})
}
func Benchmark_Dec_GobEnDecode(b *testing.B) {
doBenchmarkDec1(b, func(x *Dec) {
g, _ := x.GobEncode()
new(Dec).GobDecode(g)
})
}
func Benchmark_Dec_Add(b *testing.B) {
doBenchmarkDec2(b, func(x, y *Dec) {
ys := y.Scale()
y.SetScale(x.Scale())
_ = new(Dec).Add(x, y)
y.SetScale(ys)
})
}
func Benchmark_Dec_AddMixed(b *testing.B) {
doBenchmarkDec2(b, func(x, y *Dec) {
_ = new(Dec).Add(x, y)
})
}
func Benchmark_Dec_Sub(b *testing.B) {
doBenchmarkDec2(b, func(x, y *Dec) {
ys := y.Scale()
y.SetScale(x.Scale())
_ = new(Dec).Sub(x, y)
y.SetScale(ys)
})
}
func Benchmark_Dec_SubMixed(b *testing.B) {
doBenchmarkDec2(b, func(x, y *Dec) {
_ = new(Dec).Sub(x, y)
})
}
func Benchmark_Dec_Mul(b *testing.B) {
doBenchmarkDec2(b, func(x, y *Dec) {
_ = new(Dec).Mul(x, y)
})
}
func Benchmark_Dec_Mul_QuoExact(b *testing.B) {
doBenchmarkDec2(b, func(x, y *Dec) {
v := new(Dec).Mul(x, y)
_ = new(Dec).QuoExact(v, y)
})
}
func Benchmark_Dec_QuoRound_Fixed_Down(b *testing.B) {
doBenchmarkDec2(b, func(x, y *Dec) {
_ = new(Dec).QuoRound(x, y, 0, RoundDown)
})
}
func Benchmark_Dec_QuoRound_Fixed_HalfUp(b *testing.B) {
doBenchmarkDec2(b, func(x, y *Dec) {
_ = new(Dec).QuoRound(x, y, 0, RoundHalfUp)
})
}
func Benchmark_Int_String(b *testing.B) {
doBenchmarkInt1(b, func(x *big.Int) {
x.String()
})
}
func Benchmark_Int_StringScan(b *testing.B) {
doBenchmarkInt1(b, func(x *big.Int) {
s := x.String()
d := new(big.Int)
fmt.Sscan(s, d)
})
}
func Benchmark_Int_GobEncode(b *testing.B) {
doBenchmarkInt1(b, func(x *big.Int) {
x.GobEncode()
})
}
func Benchmark_Int_GobEnDecode(b *testing.B) {
doBenchmarkInt1(b, func(x *big.Int) {
g, _ := x.GobEncode()
new(big.Int).GobDecode(g)
})
}
func Benchmark_Int_Add(b *testing.B) {
doBenchmarkInt2(b, func(x, y *big.Int) {
_ = new(big.Int).Add(x, y)
})
}
func Benchmark_Int_Sub(b *testing.B) {
doBenchmarkInt2(b, func(x, y *big.Int) {
_ = new(big.Int).Sub(x, y)
})
}
func Benchmark_Int_Mul(b *testing.B) {
doBenchmarkInt2(b, func(x, y *big.Int) {
_ = new(big.Int).Mul(x, y)
})
}
func Benchmark_Int_Quo(b *testing.B) {
doBenchmarkInt2(b, func(x, y *big.Int) {
_ = new(big.Int).Quo(x, y)
})
}
func Benchmark_Int_QuoRem(b *testing.B) {
doBenchmarkInt2(b, func(x, y *big.Int) {
_, _ = new(big.Int).QuoRem(x, y, new(big.Int))
})
}

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Godeps/_workspace/src/speter.net/go/exp/math/dec/inf/dec.go generated vendored Normal file
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// Package inf (type inf.Dec) implements "infinite-precision" decimal
// arithmetic.
// "Infinite precision" describes two characteristics: practically unlimited
// precision for decimal number representation and no support for calculating
// with any specific fixed precision.
// (Although there is no practical limit on precision, inf.Dec can only
// represent finite decimals.)
//
// This package is currently in experimental stage and the API may change.
//
// This package does NOT support:
// - rounding to specific precisions (as opposed to specific decimal positions)
// - the notion of context (each rounding must be explicit)
// - NaN and Inf values, and distinguishing between positive and negative zero
// - conversions to and from float32/64 types
//
// Features considered for possible addition:
// + formatting options
// + Exp method
// + combined operations such as AddRound/MulAdd etc
// + exchanging data in decimal32/64/128 formats
//
package inf
// TODO:
// - avoid excessive deep copying (quo and rounders)
import (
"fmt"
"io"
"math/big"
"strings"
)
// A Dec represents a signed arbitrary-precision decimal.
// It is a combination of a sign, an arbitrary-precision integer coefficient
// value, and a signed fixed-precision exponent value.
// The sign and the coefficient value are handled together as a signed value
// and referred to as the unscaled value.
// (Positive and negative zero values are not distinguished.)
// Since the exponent is most commonly non-positive, it is handled in negated
// form and referred to as scale.
//
// The mathematical value of a Dec equals:
//
// unscaled * 10**(-scale)
//
// Note that different Dec representations may have equal mathematical values.
//
// unscaled scale String()
// -------------------------
// 0 0 "0"
// 0 2 "0.00"
// 0 -2 "0"
// 1 0 "1"
// 100 2 "1.00"
// 10 0 "10"
// 1 -1 "10"
//
// The zero value for a Dec represents the value 0 with scale 0.
//
// Operations are typically performed through the *Dec type.
// The semantics of the assignment operation "=" for "bare" Dec values is
// undefined and should not be relied on.
//
// Methods are typically of the form:
//
// func (z *Dec) Op(x, y *Dec) *Dec
//
// and implement operations z = x Op y with the result as receiver; if it
// is one of the operands it may be overwritten (and its memory reused).
// To enable chaining of operations, the result is also returned. Methods
// returning a result other than *Dec take one of the operands as the receiver.
//
// A "bare" Quo method (quotient / division operation) is not provided, as the
// result is not always a finite decimal and thus in general cannot be
// represented as a Dec.
// Instead, in the common case when rounding is (potentially) necessary,
// QuoRound should be used with a Scale and a Rounder.
// QuoExact or QuoRound with RoundExact can be used in the special cases when it
// is known that the result is always a finite decimal.
//
type Dec struct {
unscaled big.Int
scale Scale
}
// Scale represents the type used for the scale of a Dec.
type Scale int32
const scaleSize = 4 // bytes in a Scale value
// Scaler represents a method for obtaining the scale to use for the result of
// an operation on x and y.
type scaler interface {
Scale(x *Dec, y *Dec) Scale
}
var bigInt = [...]*big.Int{
big.NewInt(0), big.NewInt(1), big.NewInt(2), big.NewInt(3), big.NewInt(4),
big.NewInt(5), big.NewInt(6), big.NewInt(7), big.NewInt(8), big.NewInt(9),
big.NewInt(10),
}
var exp10cache [64]big.Int = func() [64]big.Int {
e10, e10i := [64]big.Int{}, bigInt[1]
for i, _ := range e10 {
e10[i].Set(e10i)
e10i = new(big.Int).Mul(e10i, bigInt[10])
}
return e10
}()
// NewDec allocates and returns a new Dec set to the given int64 unscaled value
// and scale.
func NewDec(unscaled int64, scale Scale) *Dec {
return new(Dec).SetUnscaled(unscaled).SetScale(scale)
}
// NewDecBig allocates and returns a new Dec set to the given *big.Int unscaled
// value and scale.
func NewDecBig(unscaled *big.Int, scale Scale) *Dec {
return new(Dec).SetUnscaledBig(unscaled).SetScale(scale)
}
// Scale returns the scale of x.
func (x *Dec) Scale() Scale {
return x.scale
}
// Unscaled returns the unscaled value of x for u and true for ok when the
// unscaled value can be represented as int64; otherwise it returns an undefined
// int64 value for u and false for ok. Use x.UnscaledBig().Int64() to avoid
// checking the validity of the value when the check is known to be redundant.
func (x *Dec) Unscaled() (u int64, ok bool) {
u = x.unscaled.Int64()
var i big.Int
ok = i.SetInt64(u).Cmp(&x.unscaled) == 0
return
}
// UnscaledBig returns the unscaled value of x as *big.Int.
func (x *Dec) UnscaledBig() *big.Int {
return &x.unscaled
}
// SetScale sets the scale of z, with the unscaled value unchanged, and returns
// z.
// The mathematical value of the Dec changes as if it was multiplied by
// 10**(oldscale-scale).
func (z *Dec) SetScale(scale Scale) *Dec {
z.scale = scale
return z
}
// SetUnscaled sets the unscaled value of z, with the scale unchanged, and
// returns z.
func (z *Dec) SetUnscaled(unscaled int64) *Dec {
z.unscaled.SetInt64(unscaled)
return z
}
// SetUnscaledBig sets the unscaled value of z, with the scale unchanged, and
// returns z.
func (z *Dec) SetUnscaledBig(unscaled *big.Int) *Dec {
z.unscaled.Set(unscaled)
return z
}
// Set sets z to the value of x and returns z.
// It does nothing if z == x.
func (z *Dec) Set(x *Dec) *Dec {
if z != x {
z.SetUnscaledBig(x.UnscaledBig())
z.SetScale(x.Scale())
}
return z
}
// Sign returns:
//
// -1 if x < 0
// 0 if x == 0
// +1 if x > 0
//
func (x *Dec) Sign() int {
return x.UnscaledBig().Sign()
}
// Neg sets z to -x and returns z.
func (z *Dec) Neg(x *Dec) *Dec {
z.SetScale(x.Scale())
z.UnscaledBig().Neg(x.UnscaledBig())
return z
}
// Cmp compares x and y and returns:
//
// -1 if x < y
// 0 if x == y
// +1 if x > y
//
func (x *Dec) Cmp(y *Dec) int {
xx, yy := upscale(x, y)
return xx.UnscaledBig().Cmp(yy.UnscaledBig())
}
// Abs sets z to |x| (the absolute value of x) and returns z.
func (z *Dec) Abs(x *Dec) *Dec {
z.SetScale(x.Scale())
z.UnscaledBig().Abs(x.UnscaledBig())
return z
}
// Add sets z to the sum x+y and returns z.
// The scale of z is the greater of the scales of x and y.
func (z *Dec) Add(x, y *Dec) *Dec {
xx, yy := upscale(x, y)
z.SetScale(xx.Scale())
z.UnscaledBig().Add(xx.UnscaledBig(), yy.UnscaledBig())
return z
}
// Sub sets z to the difference x-y and returns z.
// The scale of z is the greater of the scales of x and y.
func (z *Dec) Sub(x, y *Dec) *Dec {
xx, yy := upscale(x, y)
z.SetScale(xx.Scale())
z.UnscaledBig().Sub(xx.UnscaledBig(), yy.UnscaledBig())
return z
}
// Mul sets z to the product x*y and returns z.
// The scale of z is the sum of the scales of x and y.
func (z *Dec) Mul(x, y *Dec) *Dec {
z.SetScale(x.Scale() + y.Scale())
z.UnscaledBig().Mul(x.UnscaledBig(), y.UnscaledBig())
return z
}
// Round sets z to the value of x rounded to Scale s using Rounder r, and
// returns z.
func (z *Dec) Round(x *Dec, s Scale, r Rounder) *Dec {
return z.QuoRound(x, NewDec(1, 0), s, r)
}
// QuoRound sets z to the quotient x/y, rounded using the given Rounder to the
// specified scale.
//
// If the rounder is RoundExact but the result can not be expressed exactly at
// the specified scale, QuoRound returns nil, and the value of z is undefined.
//
// There is no corresponding Div method; the equivalent can be achieved through
// the choice of Rounder used.
//
func (z *Dec) QuoRound(x, y *Dec, s Scale, r Rounder) *Dec {
return z.quo(x, y, sclr{s}, r)
}
func (z *Dec) quo(x, y *Dec, s scaler, r Rounder) *Dec {
scl := s.Scale(x, y)
var zzz *Dec
if r.UseRemainder() {
zz, rA, rB := new(Dec).quoRem(x, y, scl, true, new(big.Int), new(big.Int))
zzz = r.Round(new(Dec), zz, rA, rB)
} else {
zz, _, _ := new(Dec).quoRem(x, y, scl, false, nil, nil)
zzz = r.Round(new(Dec), zz, nil, nil)
}
if zzz == nil {
return nil
}
return z.Set(zzz)
}
// QuoExact sets z to the quotient x/y and returns z when x/y is a finite
// decimal. Otherwise it returns nil and the value of z is undefined.
//
// The scale of a non-nil result is "x.Scale() - y.Scale()" or greater; it is
// calculated so that the remainder will be zero whenever x/y is a finite
// decimal.
func (z *Dec) QuoExact(x, y *Dec) *Dec {
return z.quo(x, y, scaleQuoExact{}, RoundExact)
}
// quoRem sets z to the quotient x/y with the scale s, and if useRem is true,
// it sets remNum and remDen to the numerator and denominator of the remainder.
// It returns z, remNum and remDen.
//
// The remainder is normalized to the range -1 < r < 1 to simplify rounding;
// that is, the results satisfy the following equation:
//
// x / y = z + (remNum/remDen) * 10**(-z.Scale())
//
// See Rounder for more details about rounding.
//
func (z *Dec) quoRem(x, y *Dec, s Scale, useRem bool,
remNum, remDen *big.Int) (*Dec, *big.Int, *big.Int) {
// difference (required adjustment) compared to "canonical" result scale
shift := s - (x.Scale() - y.Scale())
// pointers to adjusted unscaled dividend and divisor
var ix, iy *big.Int
switch {
case shift > 0:
// increased scale: decimal-shift dividend left
ix = new(big.Int).Mul(x.UnscaledBig(), exp10(shift))
iy = y.UnscaledBig()
case shift < 0:
// decreased scale: decimal-shift divisor left
ix = x.UnscaledBig()
iy = new(big.Int).Mul(y.UnscaledBig(), exp10(-shift))
default:
ix = x.UnscaledBig()
iy = y.UnscaledBig()
}
// save a copy of iy in case it to be overwritten with the result
iy2 := iy
if iy == z.UnscaledBig() {
iy2 = new(big.Int).Set(iy)
}
// set scale
z.SetScale(s)
// set unscaled
if useRem {
// Int division
_, intr := z.UnscaledBig().QuoRem(ix, iy, new(big.Int))
// set remainder
remNum.Set(intr)
remDen.Set(iy2)
} else {
z.UnscaledBig().Quo(ix, iy)
}
return z, remNum, remDen
}
type sclr struct{ s Scale }
func (s sclr) Scale(x, y *Dec) Scale {
return s.s
}
type scaleQuoExact struct{}
func (sqe scaleQuoExact) Scale(x, y *Dec) Scale {
rem := new(big.Rat).SetFrac(x.UnscaledBig(), y.UnscaledBig())
f2, f5 := factor2(rem.Denom()), factor(rem.Denom(), bigInt[5])
var f10 Scale
if f2 > f5 {
f10 = Scale(f2)
} else {
f10 = Scale(f5)
}
return x.Scale() - y.Scale() + f10
}
func factor(n *big.Int, p *big.Int) int {
// could be improved for large factors
d, f := n, 0
for {
dd, dm := new(big.Int).DivMod(d, p, new(big.Int))
if dm.Sign() == 0 {
f++
d = dd
} else {
break
}
}
return f
}
func factor2(n *big.Int) int {
// could be improved for large factors
f := 0
for ; n.Bit(f) == 0; f++ {
}
return f
}
func upscale(a, b *Dec) (*Dec, *Dec) {
if a.Scale() == b.Scale() {
return a, b
}
if a.Scale() > b.Scale() {
bb := b.rescale(a.Scale())
return a, bb
}
aa := a.rescale(b.Scale())
return aa, b
}
func exp10(x Scale) *big.Int {
if int(x) < len(exp10cache) {
return &exp10cache[int(x)]
}
return new(big.Int).Exp(bigInt[10], big.NewInt(int64(x)), nil)
}
func (x *Dec) rescale(newScale Scale) *Dec {
shift := newScale - x.Scale()
switch {
case shift < 0:
e := exp10(-shift)
return NewDecBig(new(big.Int).Quo(x.UnscaledBig(), e), newScale)
case shift > 0:
e := exp10(shift)
return NewDecBig(new(big.Int).Mul(x.UnscaledBig(), e), newScale)
}
return x
}
var zeros = []byte("00000000000000000000000000000000" +
"00000000000000000000000000000000")
var lzeros = Scale(len(zeros))
func appendZeros(s []byte, n Scale) []byte {
for i := Scale(0); i < n; i += lzeros {
if n > i+lzeros {
s = append(s, zeros...)
} else {
s = append(s, zeros[0:n-i]...)
}
}
return s
}
func (x *Dec) String() string {
if x == nil {
return "<nil>"
}
scale := x.Scale()
s := []byte(x.UnscaledBig().String())
if scale <= 0 {
if scale != 0 && x.unscaled.Sign() != 0 {
s = appendZeros(s, -scale)
}
return string(s)
}
negbit := Scale(-((x.Sign() - 1) / 2))
// scale > 0
lens := Scale(len(s))
if lens-negbit <= scale {
ss := make([]byte, 0, scale+2)
if negbit == 1 {
ss = append(ss, '-')
}
ss = append(ss, '0', '.')
ss = appendZeros(ss, scale-lens+negbit)
ss = append(ss, s[negbit:]...)
return string(ss)
}
// lens > scale
ss := make([]byte, 0, lens+1)
ss = append(ss, s[:lens-scale]...)
ss = append(ss, '.')
ss = append(ss, s[lens-scale:]...)
return string(ss)
}
// Format is a support routine for fmt.Formatter. It accepts the decimal
// formats 'd' and 'f', and handles both equivalently.
// Width, precision, flags and bases 2, 8, 16 are not supported.
func (x *Dec) Format(s fmt.State, ch rune) {
if ch != 'd' && ch != 'f' && ch != 'v' && ch != 's' {
fmt.Fprintf(s, "%%!%c(dec.Dec=%s)", ch, x.String())
return
}
fmt.Fprintf(s, x.String())
}
func (z *Dec) scan(r io.RuneScanner) (*Dec, error) {
unscaled := make([]byte, 0, 256) // collects chars of unscaled as bytes
dp, dg := -1, -1 // indexes of decimal point, first digit
loop:
for {
ch, _, err := r.ReadRune()
if err == io.EOF {
break loop
}
if err != nil {
return nil, err
}
switch {
case ch == '+' || ch == '-':
if len(unscaled) > 0 || dp >= 0 { // must be first character
r.UnreadRune()
break loop
}
case ch == '.':
if dp >= 0 {
r.UnreadRune()
break loop
}
dp = len(unscaled)
continue // don't add to unscaled
case ch >= '0' && ch <= '9':
if dg == -1 {
dg = len(unscaled)
}
default:
r.UnreadRune()
break loop
}
unscaled = append(unscaled, byte(ch))
}
if dg == -1 {
return nil, fmt.Errorf("no digits read")
}
if dp >= 0 {
z.SetScale(Scale(len(unscaled) - dp))
} else {
z.SetScale(0)
}
_, ok := z.UnscaledBig().SetString(string(unscaled), 10)
if !ok {
return nil, fmt.Errorf("invalid decimal: %s", string(unscaled))
}
return z, nil
}
// SetString sets z to the value of s, interpreted as a decimal (base 10),
// and returns z and a boolean indicating success. The scale of z is the
// number of digits after the decimal point (including any trailing 0s),
// or 0 if there is no decimal point. If SetString fails, the value of z
// is undefined but the returned value is nil.
func (z *Dec) SetString(s string) (*Dec, bool) {
r := strings.NewReader(s)
_, err := z.scan(r)
if err != nil {
return nil, false
}
_, _, err = r.ReadRune()
if err != io.EOF {
return nil, false
}
// err == io.EOF => scan consumed all of s
return z, true
}
// Scan is a support routine for fmt.Scanner; it sets z to the value of
// the scanned number. It accepts the decimal formats 'd' and 'f', and
// handles both equivalently. Bases 2, 8, 16 are not supported.
// The scale of z is the number of digits after the decimal point
// (including any trailing 0s), or 0 if there is no decimal point.
func (z *Dec) Scan(s fmt.ScanState, ch rune) error {
if ch != 'd' && ch != 'f' && ch != 's' && ch != 'v' {
return fmt.Errorf("Dec.Scan: invalid verb '%c'", ch)
}
s.SkipSpace()
_, err := z.scan(s)
return err
}
// Gob encoding version
const decGobVersion byte = 1
func scaleBytes(s Scale) []byte {
buf := make([]byte, scaleSize)
i := scaleSize
for j := 0; j < scaleSize; j++ {
i--
buf[i] = byte(s)
s >>= 8
}
return buf
}
func scale(b []byte) (s Scale) {
for j := 0; j < scaleSize; j++ {
s <<= 8
s |= Scale(b[j])
}
return
}
// GobEncode implements the gob.GobEncoder interface.
func (x *Dec) GobEncode() ([]byte, error) {
buf, err := x.UnscaledBig().GobEncode()
if err != nil {
return nil, err
}
buf = append(append(buf, scaleBytes(x.Scale())...), decGobVersion)
return buf, nil
}
// GobDecode implements the gob.GobDecoder interface.
func (z *Dec) GobDecode(buf []byte) error {
if len(buf) == 0 {
return fmt.Errorf("Dec.GobDecode: no data")
}
b := buf[len(buf)-1]
if b != decGobVersion {
return fmt.Errorf("Dec.GobDecode: encoding version %d not supported", b)
}
l := len(buf) - scaleSize - 1
err := z.UnscaledBig().GobDecode(buf[:l])
if err != nil {
return err
}
z.SetScale(scale(buf[l : l+scaleSize]))
return nil
}
// MarshalText implements the encoding.TextMarshaler interface.
func (x *Dec) MarshalText() ([]byte, error) {
return []byte(x.String()), nil
}
// UnmarshalText implements the encoding.TextUnmarshaler interface.
func (z *Dec) UnmarshalText(data []byte) error {
_, ok := z.SetString(string(data))
if !ok {
return fmt.Errorf("invalid inf.Dec")
}
return nil
}

33
Godeps/_workspace/src/speter.net/go/exp/math/dec/inf/dec_go1_2_test.go generated vendored Normal file
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// +build go1.2
package inf
import (
"encoding"
"encoding/json"
"testing"
)
var _ encoding.TextMarshaler = new(Dec)
var _ encoding.TextUnmarshaler = new(Dec)
type Obj struct {
Val *Dec
}
func TestDecJsonMarshalUnmarshal(t *testing.T) {
o := Obj{Val: NewDec(123, 2)}
js, err := json.Marshal(o)
if err != nil {
t.Fatalf("json.Marshal(%v): got %v, want ok", o, err)
}
o2 := &Obj{}
err = json.Unmarshal(js, o2)
if err != nil {
t.Fatalf("json.Unmarshal(%#q): got %v, want ok", js, err)
}
if o.Val.Scale() != o2.Val.Scale() ||
o.Val.UnscaledBig().Cmp(o2.Val.UnscaledBig()) != 0 {
t.Fatalf("json.Unmarshal(json.Marshal(%v)): want %v, got %v", o, o, o2)
}
}

40
Godeps/_workspace/src/speter.net/go/exp/math/dec/inf/dec_internal_test.go generated vendored Normal file
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@ -0,0 +1,40 @@
package inf
import (
"math/big"
"testing"
)
var decQuoRemZZZ = []struct {
z, x, y *Dec
r *big.Rat
srA, srB int
}{
// basic examples
{NewDec(1, 0), NewDec(2, 0), NewDec(2, 0), big.NewRat(0, 1), 0, 1},
{NewDec(15, 1), NewDec(3, 0), NewDec(2, 0), big.NewRat(0, 1), 0, 1},
{NewDec(1, 1), NewDec(1, 0), NewDec(10, 0), big.NewRat(0, 1), 0, 1},
{NewDec(0, 0), NewDec(2, 0), NewDec(3, 0), big.NewRat(2, 3), 1, 1},
{NewDec(0, 0), NewDec(2, 0), NewDec(6, 0), big.NewRat(1, 3), 1, 1},
{NewDec(1, 1), NewDec(2, 0), NewDec(12, 0), big.NewRat(2, 3), 1, 1},
// examples from the Go Language Specification
{NewDec(1, 0), NewDec(5, 0), NewDec(3, 0), big.NewRat(2, 3), 1, 1},
{NewDec(-1, 0), NewDec(-5, 0), NewDec(3, 0), big.NewRat(-2, 3), -1, 1},
{NewDec(-1, 0), NewDec(5, 0), NewDec(-3, 0), big.NewRat(-2, 3), 1, -1},
{NewDec(1, 0), NewDec(-5, 0), NewDec(-3, 0), big.NewRat(2, 3), -1, -1},
}
func TestDecQuoRem(t *testing.T) {
for i, a := range decQuoRemZZZ {
z, rA, rB := new(Dec), new(big.Int), new(big.Int)
s := scaleQuoExact{}.Scale(a.x, a.y)
z.quoRem(a.x, a.y, s, true, rA, rB)
if a.z.Cmp(z) != 0 || a.r.Cmp(new(big.Rat).SetFrac(rA, rB)) != 0 {
t.Errorf("#%d QuoRemZZZ got %v, %v, %v; expected %v, %v", i, z, rA, rB, a.z, a.r)
}
if a.srA != rA.Sign() || a.srB != rB.Sign() {
t.Errorf("#%d QuoRemZZZ wrong signs, got %v, %v; expected %v, %v", i, rA.Sign(), rB.Sign(), a.srA, a.srB)
}
}
}

379
Godeps/_workspace/src/speter.net/go/exp/math/dec/inf/dec_test.go generated vendored Normal file
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package inf_test
import (
"bytes"
"encoding/gob"
"fmt"
"math/big"
"strings"
"testing"
"speter.net/go/exp/math/dec/inf"
)
type decFunZZ func(z, x, y *inf.Dec) *inf.Dec
type decArgZZ struct {
z, x, y *inf.Dec
}
var decSumZZ = []decArgZZ{
{inf.NewDec(0, 0), inf.NewDec(0, 0), inf.NewDec(0, 0)},
{inf.NewDec(1, 0), inf.NewDec(1, 0), inf.NewDec(0, 0)},
{inf.NewDec(1111111110, 0), inf.NewDec(123456789, 0), inf.NewDec(987654321, 0)},
{inf.NewDec(-1, 0), inf.NewDec(-1, 0), inf.NewDec(0, 0)},
{inf.NewDec(864197532, 0), inf.NewDec(-123456789, 0), inf.NewDec(987654321, 0)},
{inf.NewDec(-1111111110, 0), inf.NewDec(-123456789, 0), inf.NewDec(-987654321, 0)},
{inf.NewDec(12, 2), inf.NewDec(1, 1), inf.NewDec(2, 2)},
}
var decProdZZ = []decArgZZ{
{inf.NewDec(0, 0), inf.NewDec(0, 0), inf.NewDec(0, 0)},
{inf.NewDec(0, 0), inf.NewDec(1, 0), inf.NewDec(0, 0)},
{inf.NewDec(1, 0), inf.NewDec(1, 0), inf.NewDec(1, 0)},
{inf.NewDec(-991*991, 0), inf.NewDec(991, 0), inf.NewDec(-991, 0)},
{inf.NewDec(2, 3), inf.NewDec(1, 1), inf.NewDec(2, 2)},
{inf.NewDec(2, -3), inf.NewDec(1, -1), inf.NewDec(2, -2)},
{inf.NewDec(2, 3), inf.NewDec(1, 1), inf.NewDec(2, 2)},
}
func TestDecSignZ(t *testing.T) {
var zero inf.Dec
for _, a := range decSumZZ {
s := a.z.Sign()
e := a.z.Cmp(&zero)
if s != e {
t.Errorf("got %d; want %d for z = %v", s, e, a.z)
}
}
}
func TestDecAbsZ(t *testing.T) {
var zero inf.Dec
for _, a := range decSumZZ {
var z inf.Dec
z.Abs(a.z)
var e inf.Dec
e.Set(a.z)
if e.Cmp(&zero) < 0 {
e.Sub(&zero, &e)
}
if z.Cmp(&e) != 0 {
t.Errorf("got z = %v; want %v", z, e)
}
}
}
func testDecFunZZ(t *testing.T, msg string, f decFunZZ, a decArgZZ) {
var z inf.Dec
f(&z, a.x, a.y)
if (&z).Cmp(a.z) != 0 {
t.Errorf("%s%+v\n\tgot z = %v; want %v", msg, a, &z, a.z)
}
}
func TestDecSumZZ(t *testing.T) {
AddZZ := func(z, x, y *inf.Dec) *inf.Dec { return z.Add(x, y) }
SubZZ := func(z, x, y *inf.Dec) *inf.Dec { return z.Sub(x, y) }
for _, a := range decSumZZ {
arg := a
testDecFunZZ(t, "AddZZ", AddZZ, arg)
arg = decArgZZ{a.z, a.y, a.x}
testDecFunZZ(t, "AddZZ symmetric", AddZZ, arg)
arg = decArgZZ{a.x, a.z, a.y}
testDecFunZZ(t, "SubZZ", SubZZ, arg)
arg = decArgZZ{a.y, a.z, a.x}
testDecFunZZ(t, "SubZZ symmetric", SubZZ, arg)
}
}
func TestDecProdZZ(t *testing.T) {
MulZZ := func(z, x, y *inf.Dec) *inf.Dec { return z.Mul(x, y) }
for _, a := range decProdZZ {
arg := a
testDecFunZZ(t, "MulZZ", MulZZ, arg)
arg = decArgZZ{a.z, a.y, a.x}
testDecFunZZ(t, "MulZZ symmetric", MulZZ, arg)
}
}
var decUnscaledTests = []struct {
d *inf.Dec
u int64 // ignored when ok == false
ok bool
}{
{new(inf.Dec), 0, true},
{inf.NewDec(-1<<63, 0), -1 << 63, true},
{inf.NewDec(-(-1<<63 + 1), 0), -(-1<<63 + 1), true},
{new(inf.Dec).Neg(inf.NewDec(-1<<63, 0)), 0, false},
{new(inf.Dec).Sub(inf.NewDec(-1<<63, 0), inf.NewDec(1, 0)), 0, false},
{inf.NewDecBig(new(big.Int).Lsh(big.NewInt(1), 64), 0), 0, false},
}
func TestDecUnscaled(t *testing.T) {
for i, tt := range decUnscaledTests {
u, ok := tt.d.Unscaled()
if ok != tt.ok {
t.Errorf("#%d Unscaled: got %v, expected %v", i, ok, tt.ok)
} else if ok && u != tt.u {
t.Errorf("#%d Unscaled: got %v, expected %v", i, u, tt.u)
}
}
}
var decRoundTests = [...]struct {
in *inf.Dec
s inf.Scale
r inf.Rounder
exp *inf.Dec
}{
{inf.NewDec(123424999999999993, 15), 2, inf.RoundHalfUp, inf.NewDec(12342, 2)},
{inf.NewDec(123425000000000001, 15), 2, inf.RoundHalfUp, inf.NewDec(12343, 2)},
{inf.NewDec(123424999999999993, 15), 15, inf.RoundHalfUp, inf.NewDec(123424999999999993, 15)},
{inf.NewDec(123424999999999993, 15), 16, inf.RoundHalfUp, inf.NewDec(1234249999999999930, 16)},
{inf.NewDecBig(new(big.Int).Lsh(big.NewInt(1), 64), 0), -1, inf.RoundHalfUp, inf.NewDec(1844674407370955162, -1)},
{inf.NewDecBig(new(big.Int).Lsh(big.NewInt(1), 64), 0), -2, inf.RoundHalfUp, inf.NewDec(184467440737095516, -2)},
{inf.NewDecBig(new(big.Int).Lsh(big.NewInt(1), 64), 0), -3, inf.RoundHalfUp, inf.NewDec(18446744073709552, -3)},
{inf.NewDecBig(new(big.Int).Lsh(big.NewInt(1), 64), 0), -4, inf.RoundHalfUp, inf.NewDec(1844674407370955, -4)},
{inf.NewDecBig(new(big.Int).Lsh(big.NewInt(1), 64), 0), -5, inf.RoundHalfUp, inf.NewDec(184467440737096, -5)},
{inf.NewDecBig(new(big.Int).Lsh(big.NewInt(1), 64), 0), -6, inf.RoundHalfUp, inf.NewDec(18446744073710, -6)},
}
func TestDecRound(t *testing.T) {
for i, tt := range decRoundTests {
z := new(inf.Dec).Round(tt.in, tt.s, tt.r)
if tt.exp.Cmp(z) != 0 {
t.Errorf("#%d Round got %v; expected %v", i, z, tt.exp)
}
}
}
var decStringTests = []struct {
in string
out string
val int64
scale inf.Scale // skip SetString if negative
ok bool
scanOk bool
}{
{in: "", ok: false, scanOk: false},
{in: "a", ok: false, scanOk: false},
{in: "z", ok: false, scanOk: false},
{in: "+", ok: false, scanOk: false},
{in: "-", ok: false, scanOk: false},
{in: "g", ok: false, scanOk: false},
{in: ".", ok: false, scanOk: false},
{in: ".-0", ok: false, scanOk: false},
{in: ".+0", ok: false, scanOk: false},
// Scannable but not SetStringable
{"0b", "ignored", 0, 0, false, true},
{"0x", "ignored", 0, 0, false, true},
{"0xg", "ignored", 0, 0, false, true},
{"0.0g", "ignored", 0, 1, false, true},
// examples from godoc for Dec
{"0", "0", 0, 0, true, true},
{"0.00", "0.00", 0, 2, true, true},
{"ignored", "0", 0, -2, true, false},
{"1", "1", 1, 0, true, true},
{"1.00", "1.00", 100, 2, true, true},
{"10", "10", 10, 0, true, true},
{"ignored", "10", 1, -1, true, false},
// other tests
{"+0", "0", 0, 0, true, true},
{"-0", "0", 0, 0, true, true},
{"0.0", "0.0", 0, 1, true, true},
{"0.1", "0.1", 1, 1, true, true},
{"0.", "0", 0, 0, true, true},
{"-10", "-10", -1, -1, true, true},
{"-1", "-1", -1, 0, true, true},
{"-0.1", "-0.1", -1, 1, true, true},
{"-0.01", "-0.01", -1, 2, true, true},
{"+0.", "0", 0, 0, true, true},
{"-0.", "0", 0, 0, true, true},
{".0", "0.0", 0, 1, true, true},
{"+.0", "0.0", 0, 1, true, true},
{"-.0", "0.0", 0, 1, true, true},
{"0.0000000000", "0.0000000000", 0, 10, true, true},
{"0.0000000001", "0.0000000001", 1, 10, true, true},
{"-0.0000000000", "0.0000000000", 0, 10, true, true},
{"-0.0000000001", "-0.0000000001", -1, 10, true, true},
{"-10", "-10", -10, 0, true, true},
{"+10", "10", 10, 0, true, true},
{"00", "0", 0, 0, true, true},
{"023", "23", 23, 0, true, true}, // decimal, not octal
{"-02.3", "-2.3", -23, 1, true, true}, // decimal, not octal
}
func TestDecGetString(t *testing.T) {
z := new(inf.Dec)
for i, test := range decStringTests {
if !test.ok {
continue
}
z.SetUnscaled(test.val)
z.SetScale(test.scale)
s := z.String()
if s != test.out {
t.Errorf("#%da got %s; want %s", i, s, test.out)
}
s = fmt.Sprintf("%d", z)
if s != test.out {
t.Errorf("#%db got %s; want %s", i, s, test.out)
}
}
}
func TestDecSetString(t *testing.T) {
tmp := new(inf.Dec)
for i, test := range decStringTests {
if test.scale < 0 {
// SetString only supports scale >= 0
continue
}
// initialize to a non-zero value so that issues with parsing
// 0 are detected
tmp.Set(inf.NewDec(1234567890, 123))
n1, ok1 := new(inf.Dec).SetString(test.in)
n2, ok2 := tmp.SetString(test.in)
expected := inf.NewDec(test.val, test.scale)
if ok1 != test.ok || ok2 != test.ok {
t.Errorf("#%d (input '%s') ok incorrect (should be %t)", i, test.in, test.ok)
continue
}
if !ok1 {
if n1 != nil {
t.Errorf("#%d (input '%s') n1 != nil", i, test.in)
}
continue
}
if !ok2 {
if n2 != nil {
t.Errorf("#%d (input '%s') n2 != nil", i, test.in)
}
continue
}
if n1.Cmp(expected) != 0 {
t.Errorf("#%d (input '%s') got: %s want: %d", i, test.in, n1, test.val)
}
if n2.Cmp(expected) != 0 {
t.Errorf("#%d (input '%s') got: %s want: %d", i, test.in, n2, test.val)
}
}
}
func TestDecScan(t *testing.T) {
tmp := new(inf.Dec)
for i, test := range decStringTests {
if test.scale < 0 {
// SetString only supports scale >= 0
continue
}
// initialize to a non-zero value so that issues with parsing
// 0 are detected
tmp.Set(inf.NewDec(1234567890, 123))
n1, n2 := new(inf.Dec), tmp
nn1, err1 := fmt.Sscan(test.in, n1)
nn2, err2 := fmt.Sscan(test.in, n2)
if !test.scanOk {
if err1 == nil || err2 == nil {
t.Errorf("#%d (input '%s') ok incorrect, should be %t", i, test.in, test.scanOk)
}
continue
}
expected := inf.NewDec(test.val, test.scale)
if nn1 != 1 || err1 != nil || nn2 != 1 || err2 != nil {
t.Errorf("#%d (input '%s') error %d %v, %d %v", i, test.in, nn1, err1, nn2, err2)
continue
}
if n1.Cmp(expected) != 0 {
t.Errorf("#%d (input '%s') got: %s want: %d", i, test.in, n1, test.val)
}
if n2.Cmp(expected) != 0 {
t.Errorf("#%d (input '%s') got: %s want: %d", i, test.in, n2, test.val)
}
}
}
var decScanNextTests = []struct {
in string
ok bool
next rune
}{
{"", false, 0},
{"a", false, 'a'},
{"z", false, 'z'},
{"+", false, 0},
{"-", false, 0},
{"g", false, 'g'},
{".", false, 0},
{".-0", false, '-'},
{".+0", false, '+'},
{"0b", true, 'b'},
{"0x", true, 'x'},
{"0xg", true, 'x'},
{"0.0g", true, 'g'},
}
func TestDecScanNext(t *testing.T) {
for i, test := range decScanNextTests {
rdr := strings.NewReader(test.in)
n1 := new(inf.Dec)
nn1, _ := fmt.Fscan(rdr, n1)
if (test.ok && nn1 == 0) || (!test.ok && nn1 > 0) {
t.Errorf("#%d (input '%s') ok incorrect should be %t", i, test.in, test.ok)
continue
}
r := rune(0)
nn2, err := fmt.Fscanf(rdr, "%c", &r)
if test.next != r {
t.Errorf("#%d (input '%s') next incorrect, got %c should be %c, %d, %v", i, test.in, r, test.next, nn2, err)
}
}
}
var decGobEncodingTests = []string{
"0",
"1",
"2",
"10",
"42",
"1234567890",
"298472983472983471903246121093472394872319615612417471234712061",
}
func TestDecGobEncoding(t *testing.T) {
var medium bytes.Buffer
enc := gob.NewEncoder(&medium)
dec := gob.NewDecoder(&medium)
for i, test := range decGobEncodingTests {
for j := 0; j < 2; j++ {
for k := inf.Scale(-5); k <= 5; k++ {
medium.Reset() // empty buffer for each test case (in case of failures)
stest := test
if j != 0 {
// negative numbers
stest = "-" + test
}
var tx inf.Dec
tx.SetString(stest)
tx.SetScale(k) // test with positive, negative, and zero scale
if err := enc.Encode(&tx); err != nil {
t.Errorf("#%d%c: encoding failed: %s", i, 'a'+j, err)
}
var rx inf.Dec
if err := dec.Decode(&rx); err != nil {
t.Errorf("#%d%c: decoding failed: %s", i, 'a'+j, err)
}
if rx.Cmp(&tx) != 0 {
t.Errorf("#%d%c: transmission failed: got %s want %s", i, 'a'+j, &rx, &tx)
}
}
}
}
}

62
Godeps/_workspace/src/speter.net/go/exp/math/dec/inf/example_test.go generated vendored Normal file
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@ -0,0 +1,62 @@
package inf_test
import (
"fmt"
"log"
)
import "speter.net/go/exp/math/dec/inf"
func ExampleDec_SetString() {
d := new(inf.Dec)
d.SetString("012345.67890") // decimal; leading 0 ignored; trailing 0 kept
fmt.Println(d)
// Output: 12345.67890
}
func ExampleDec_Scan() {
// The Scan function is rarely used directly;
// the fmt package recognizes it as an implementation of fmt.Scanner.
d := new(inf.Dec)
_, err := fmt.Sscan("184467440.73709551617", d)
if err != nil {
log.Println("error scanning value:", err)
} else {
fmt.Println(d)
}
// Output: 184467440.73709551617
}
func ExampleDec_QuoRound_scale2RoundDown() {
// 10 / 3 is an infinite decimal; it has no exact Dec representation
x, y := inf.NewDec(10, 0), inf.NewDec(3, 0)
// use 2 digits beyond the decimal point, round towards 0
z := new(inf.Dec).QuoRound(x, y, 2, inf.RoundDown)
fmt.Println(z)
// Output: 3.33
}
func ExampleDec_QuoRound_scale2RoundCeil() {
// -42 / 400 is an finite decimal with 3 digits beyond the decimal point
x, y := inf.NewDec(-42, 0), inf.NewDec(400, 0)
// use 2 digits beyond decimal point, round towards positive infinity
z := new(inf.Dec).QuoRound(x, y, 2, inf.RoundCeil)
fmt.Println(z)
// Output: -0.10
}
func ExampleDec_QuoExact_ok() {
// 1 / 25 is a finite decimal; it has exact Dec representation
x, y := inf.NewDec(1, 0), inf.NewDec(25, 0)
z := new(inf.Dec).QuoExact(x, y)
fmt.Println(z)
// Output: 0.04
}
func ExampleDec_QuoExact_fail() {
// 1 / 3 is an infinite decimal; it has no exact Dec representation
x, y := inf.NewDec(1, 0), inf.NewDec(3, 0)
z := new(inf.Dec).QuoExact(x, y)
fmt.Println(z)
// Output: <nil>
}

145
Godeps/_workspace/src/speter.net/go/exp/math/dec/inf/rounder.go generated vendored Normal file
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@ -0,0 +1,145 @@
package inf
import (
"math/big"
)
// Rounder represents a method for rounding the (possibly infinite decimal)
// result of a division to a finite Dec. It is used by Dec.Round() and
// Dec.Quo().
//
// See the Example for results of using each Rounder with some sample values.
//
type Rounder rounder
// See http://speleotrove.com/decimal/damodel.html#refround for more detailed
// definitions of these rounding modes.
var (
RoundDown Rounder // towards 0
RoundUp Rounder // away from 0
RoundFloor Rounder // towards -infinity
RoundCeil Rounder // towards +infinity
RoundHalfDown Rounder // to nearest; towards 0 if same distance
RoundHalfUp Rounder // to nearest; away from 0 if same distance
RoundHalfEven Rounder // to nearest; even last digit if same distance
)
// RoundExact is to be used in the case when rounding is not necessary.
// When used with Quo or Round, it returns the result verbatim when it can be
// expressed exactly with the given precision, and it returns nil otherwise.
// QuoExact is a shorthand for using Quo with RoundExact.
var RoundExact Rounder
type rounder interface {
// When UseRemainder() returns true, the Round() method is passed the
// remainder of the division, expressed as the numerator and denominator of
// a rational.
UseRemainder() bool
// Round sets the rounded value of a quotient to z, and returns z.
// quo is rounded down (truncated towards zero) to the scale obtained from
// the Scaler in Quo().
//
// When the remainder is not used, remNum and remDen are nil.
// When used, the remainder is normalized between -1 and 1; that is:
//
// -|remDen| < remNum < |remDen|
//
// remDen has the same sign as y, and remNum is zero or has the same sign
// as x.
Round(z, quo *Dec, remNum, remDen *big.Int) *Dec
}
type rndr struct {
useRem bool
round func(z, quo *Dec, remNum, remDen *big.Int) *Dec
}
func (r rndr) UseRemainder() bool {
return r.useRem
}
func (r rndr) Round(z, quo *Dec, remNum, remDen *big.Int) *Dec {
return r.round(z, quo, remNum, remDen)
}
var intSign = []*big.Int{big.NewInt(-1), big.NewInt(0), big.NewInt(1)}
func roundHalf(f func(c int, odd uint) (roundUp bool)) func(z, q *Dec, rA, rB *big.Int) *Dec {
return func(z, q *Dec, rA, rB *big.Int) *Dec {
z.Set(q)
brA, brB := rA.BitLen(), rB.BitLen()
if brA < brB-1 {
// brA < brB-1 => |rA| < |rB/2|
return z
}
roundUp := false
srA, srB := rA.Sign(), rB.Sign()
s := srA * srB
if brA == brB-1 {
rA2 := new(big.Int).Lsh(rA, 1)
if s < 0 {
rA2.Neg(rA2)
}
roundUp = f(rA2.Cmp(rB)*srB, z.UnscaledBig().Bit(0))
} else {
// brA > brB-1 => |rA| > |rB/2|
roundUp = true
}
if roundUp {
z.UnscaledBig().Add(z.UnscaledBig(), intSign[s+1])
}
return z
}
}
func init() {
RoundExact = rndr{true,
func(z, q *Dec, rA, rB *big.Int) *Dec {
if rA.Sign() != 0 {
return nil
}
return z.Set(q)
}}
RoundDown = rndr{false,
func(z, q *Dec, rA, rB *big.Int) *Dec {
return z.Set(q)
}}
RoundUp = rndr{true,
func(z, q *Dec, rA, rB *big.Int) *Dec {
z.Set(q)
if rA.Sign() != 0 {
z.UnscaledBig().Add(z.UnscaledBig(), intSign[rA.Sign()*rB.Sign()+1])
}
return z
}}
RoundFloor = rndr{true,
func(z, q *Dec, rA, rB *big.Int) *Dec {
z.Set(q)
if rA.Sign()*rB.Sign() < 0 {
z.UnscaledBig().Add(z.UnscaledBig(), intSign[0])
}
return z
}}
RoundCeil = rndr{true,
func(z, q *Dec, rA, rB *big.Int) *Dec {
z.Set(q)
if rA.Sign()*rB.Sign() > 0 {
z.UnscaledBig().Add(z.UnscaledBig(), intSign[2])
}
return z
}}
RoundHalfDown = rndr{true, roundHalf(
func(c int, odd uint) bool {
return c > 0
})}
RoundHalfUp = rndr{true, roundHalf(
func(c int, odd uint) bool {
return c >= 0
})}
RoundHalfEven = rndr{true, roundHalf(
func(c int, odd uint) bool {
return c > 0 || c == 0 && odd == 1
})}
}

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package inf_test
import (
"fmt"
"os"
"text/tabwriter"
"speter.net/go/exp/math/dec/inf"
)
// This example displays the results of Dec.Round with each of the Rounders.
//
func ExampleRounder() {
var vals = []struct {
x string
s inf.Scale
}{
{"-0.18", 1}, {"-0.15", 1}, {"-0.12", 1}, {"-0.10", 1},
{"-0.08", 1}, {"-0.05", 1}, {"-0.02", 1}, {"0.00", 1},
{"0.02", 1}, {"0.05", 1}, {"0.08", 1}, {"0.10", 1},
{"0.12", 1}, {"0.15", 1}, {"0.18", 1},
}
var rounders = []struct {
name string
rounder inf.Rounder
}{
{"RoundDown", inf.RoundDown}, {"RoundUp", inf.RoundUp},
{"RoundCeil", inf.RoundCeil}, {"RoundFloor", inf.RoundFloor},
{"RoundHalfDown", inf.RoundHalfDown}, {"RoundHalfUp", inf.RoundHalfUp},
{"RoundHalfEven", inf.RoundHalfEven}, {"RoundExact", inf.RoundExact},
}
fmt.Println("The results of new(inf.Dec).Round(x, s, inf.RoundXXX):\n")
w := tabwriter.NewWriter(os.Stdout, 0, 0, 1, ' ', tabwriter.AlignRight)
fmt.Fprint(w, "x\ts\t|\t")
for _, r := range rounders {
fmt.Fprintf(w, "%s\t", r.name[5:])
}
fmt.Fprintln(w)
for _, v := range vals {
fmt.Fprintf(w, "%s\t%d\t|\t", v.x, v.s)
for _, r := range rounders {
x, _ := new(inf.Dec).SetString(v.x)
z := new(inf.Dec).Round(x, v.s, r.rounder)
fmt.Fprintf(w, "%d\t", z)
}
fmt.Fprintln(w)
}
w.Flush()
// Output:
// The results of new(inf.Dec).Round(x, s, inf.RoundXXX):
//
// x s | Down Up Ceil Floor HalfDown HalfUp HalfEven Exact
// -0.18 1 | -0.1 -0.2 -0.1 -0.2 -0.2 -0.2 -0.2 <nil>
// -0.15 1 | -0.1 -0.2 -0.1 -0.2 -0.1 -0.2 -0.2 <nil>
// -0.12 1 | -0.1 -0.2 -0.1 -0.2 -0.1 -0.1 -0.1 <nil>
// -0.10 1 | -0.1 -0.1 -0.1 -0.1 -0.1 -0.1 -0.1 -0.1
// -0.08 1 | 0.0 -0.1 0.0 -0.1 -0.1 -0.1 -0.1 <nil>
// -0.05 1 | 0.0 -0.1 0.0 -0.1 0.0 -0.1 0.0 <nil>
// -0.02 1 | 0.0 -0.1 0.0 -0.1 0.0 0.0 0.0 <nil>
// 0.00 1 | 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
// 0.02 1 | 0.0 0.1 0.1 0.0 0.0 0.0 0.0 <nil>
// 0.05 1 | 0.0 0.1 0.1 0.0 0.0 0.1 0.0 <nil>
// 0.08 1 | 0.0 0.1 0.1 0.0 0.1 0.1 0.1 <nil>
// 0.10 1 | 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
// 0.12 1 | 0.1 0.2 0.2 0.1 0.1 0.1 0.1 <nil>
// 0.15 1 | 0.1 0.2 0.2 0.1 0.1 0.2 0.2 <nil>
// 0.18 1 | 0.1 0.2 0.2 0.1 0.2 0.2 0.2 <nil>
}

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package inf_test
import (
"math/big"
"testing"
"speter.net/go/exp/math/dec/inf"
)
var decRounderInputs = [...]struct {
quo *inf.Dec
rA, rB *big.Int
}{
// examples from go language spec
{inf.NewDec(1, 0), big.NewInt(2), big.NewInt(3)}, // 5 / 3
{inf.NewDec(-1, 0), big.NewInt(-2), big.NewInt(3)}, // -5 / 3
{inf.NewDec(-1, 0), big.NewInt(2), big.NewInt(-3)}, // 5 / -3
{inf.NewDec(1, 0), big.NewInt(-2), big.NewInt(-3)}, // -5 / -3
// examples from godoc
{inf.NewDec(-1, 1), big.NewInt(-8), big.NewInt(10)},
{inf.NewDec(-1, 1), big.NewInt(-5), big.NewInt(10)},
{inf.NewDec(-1, 1), big.NewInt(-2), big.NewInt(10)},
{inf.NewDec(0, 1), big.NewInt(-8), big.NewInt(10)},
{inf.NewDec(0, 1), big.NewInt(-5), big.NewInt(10)},
{inf.NewDec(0, 1), big.NewInt(-2), big.NewInt(10)},
{inf.NewDec(0, 1), big.NewInt(0), big.NewInt(1)},
{inf.NewDec(0, 1), big.NewInt(2), big.NewInt(10)},
{inf.NewDec(0, 1), big.NewInt(5), big.NewInt(10)},
{inf.NewDec(0, 1), big.NewInt(8), big.NewInt(10)},
{inf.NewDec(1, 1), big.NewInt(2), big.NewInt(10)},
{inf.NewDec(1, 1), big.NewInt(5), big.NewInt(10)},
{inf.NewDec(1, 1), big.NewInt(8), big.NewInt(10)},
}
var decRounderResults = [...]struct {
rounder inf.Rounder
results [len(decRounderInputs)]*inf.Dec
}{
{inf.RoundExact, [...]*inf.Dec{nil, nil, nil, nil,
nil, nil, nil, nil, nil, nil,
inf.NewDec(0, 1), nil, nil, nil, nil, nil, nil}},
{inf.RoundDown, [...]*inf.Dec{
inf.NewDec(1, 0), inf.NewDec(-1, 0), inf.NewDec(-1, 0), inf.NewDec(1, 0),
inf.NewDec(-1, 1), inf.NewDec(-1, 1), inf.NewDec(-1, 1),
inf.NewDec(0, 1), inf.NewDec(0, 1), inf.NewDec(0, 1),
inf.NewDec(0, 1),
inf.NewDec(0, 1), inf.NewDec(0, 1), inf.NewDec(0, 1),
inf.NewDec(1, 1), inf.NewDec(1, 1), inf.NewDec(1, 1)}},
{inf.RoundUp, [...]*inf.Dec{
inf.NewDec(2, 0), inf.NewDec(-2, 0), inf.NewDec(-2, 0), inf.NewDec(2, 0),
inf.NewDec(-2, 1), inf.NewDec(-2, 1), inf.NewDec(-2, 1),
inf.NewDec(-1, 1), inf.NewDec(-1, 1), inf.NewDec(-1, 1),
inf.NewDec(0, 1),
inf.NewDec(1, 1), inf.NewDec(1, 1), inf.NewDec(1, 1),
inf.NewDec(2, 1), inf.NewDec(2, 1), inf.NewDec(2, 1)}},
{inf.RoundHalfDown, [...]*inf.Dec{
inf.NewDec(2, 0), inf.NewDec(-2, 0), inf.NewDec(-2, 0), inf.NewDec(2, 0),
inf.NewDec(-2, 1), inf.NewDec(-1, 1), inf.NewDec(-1, 1),
inf.NewDec(-1, 1), inf.NewDec(0, 1), inf.NewDec(0, 1),
inf.NewDec(0, 1),
inf.NewDec(0, 1), inf.NewDec(0, 1), inf.NewDec(1, 1),
inf.NewDec(1, 1), inf.NewDec(1, 1), inf.NewDec(2, 1)}},
{inf.RoundHalfUp, [...]*inf.Dec{
inf.NewDec(2, 0), inf.NewDec(-2, 0), inf.NewDec(-2, 0), inf.NewDec(2, 0),
inf.NewDec(-2, 1), inf.NewDec(-2, 1), inf.NewDec(-1, 1),
inf.NewDec(-1, 1), inf.NewDec(-1, 1), inf.NewDec(0, 1),
inf.NewDec(0, 1),
inf.NewDec(0, 1), inf.NewDec(1, 1), inf.NewDec(1, 1),
inf.NewDec(1, 1), inf.NewDec(2, 1), inf.NewDec(2, 1)}},
{inf.RoundHalfEven, [...]*inf.Dec{
inf.NewDec(2, 0), inf.NewDec(-2, 0), inf.NewDec(-2, 0), inf.NewDec(2, 0),
inf.NewDec(-2, 1), inf.NewDec(-2, 1), inf.NewDec(-1, 1),
inf.NewDec(-1, 1), inf.NewDec(0, 1), inf.NewDec(0, 1),
inf.NewDec(0, 1),
inf.NewDec(0, 1), inf.NewDec(0, 1), inf.NewDec(1, 1),
inf.NewDec(1, 1), inf.NewDec(2, 1), inf.NewDec(2, 1)}},
{inf.RoundFloor, [...]*inf.Dec{
inf.NewDec(1, 0), inf.NewDec(-2, 0), inf.NewDec(-2, 0), inf.NewDec(1, 0),
inf.NewDec(-2, 1), inf.NewDec(-2, 1), inf.NewDec(-2, 1),
inf.NewDec(-1, 1), inf.NewDec(-1, 1), inf.NewDec(-1, 1),
inf.NewDec(0, 1),
inf.NewDec(0, 1), inf.NewDec(0, 1), inf.NewDec(0, 1),
inf.NewDec(1, 1), inf.NewDec(1, 1), inf.NewDec(1, 1)}},
{inf.RoundCeil, [...]*inf.Dec{
inf.NewDec(2, 0), inf.NewDec(-1, 0), inf.NewDec(-1, 0), inf.NewDec(2, 0),
inf.NewDec(-1, 1), inf.NewDec(-1, 1), inf.NewDec(-1, 1),
inf.NewDec(0, 1), inf.NewDec(0, 1), inf.NewDec(0, 1),
inf.NewDec(0, 1),
inf.NewDec(1, 1), inf.NewDec(1, 1), inf.NewDec(1, 1),
inf.NewDec(2, 1), inf.NewDec(2, 1), inf.NewDec(2, 1)}},
}
func TestDecRounders(t *testing.T) {
for i, a := range decRounderResults {
for j, input := range decRounderInputs {
q := new(inf.Dec).Set(input.quo)
rA, rB := new(big.Int).Set(input.rA), new(big.Int).Set(input.rB)
res := a.rounder.Round(new(inf.Dec), q, rA, rB)
if a.results[j] == nil && res == nil {
continue
}
if (a.results[j] == nil && res != nil) ||
(a.results[j] != nil && res == nil) ||
a.results[j].Cmp(res) != 0 {
t.Errorf("#%d,%d Rounder got %v; expected %v", i, j, res, a.results[j])
}
}
}
}