Merge aa8a681072 into d00399e161

Zero.go defines convenience functions for testing decimal values with the zero value. These functions make code using decimal easier to read in my opinion. EqualZero() could be renamed into IsZero()

helpers.go

@@ -0,0 +1,38 @@
+package decimal
+
+// Float returns the decimal value as a float64
+// float is a helper function for float64() and doesnot return bool exact
+func (d Decimal) Float() float64 {
+	f, _ := d.Float64()
+	return f
+}
+
+// NotEqual returns true when d is not equal to d2
+func (d Decimal) NotEqual(d2 Decimal) bool {
+	return !d.Equal(d2)
+}
+
+// Max returns the maximum value between d and d2
+func (d Decimal) Max(d2 Decimal) Decimal {
+	return Max(d, d2)
+}
+
+// Min returns the minimum value between d and d2
+func (d Decimal) Min(d2 Decimal) Decimal {
+	return Min(d, d2)
+}
+
+//NewFromInt returns a decimal with the value of int v
+func NewFromInt(v int) Decimal {
+	return New(int64(v), 0)
+}
+
+//NewFromInt32 returns a decimal with the value of int v
+func NewFromInt32(v int) Decimal {
+	return New(int64(v), 0)
+}
+
+//NewFromInt64 returns a decimal with the value of int v
+func NewFromInt64(v int64) Decimal {
+	return New(v, 0)
+}

numbers.go

@@ -0,0 +1,124 @@
+package decimal
+
+// MinusOne defines value -1 in decimal format
+var MinusOne = New(-1, 0)
+
+// OneTenth defines value 0.1 in decimal format
+var OneTenth = New(1, -1)
+
+// TwoTenth defines value 0.1 in decimal format
+var TwoTenth = New(2, -1)
+
+// Half defines value 0.5 in decimal format
+var Half = New(5, -1)
+
+// One defines value 1 in decimal format
+var One = New(1, 0)
+
+// Two defines value 2 in decimal format
+var Two = New(2, 0)
+
+// Three defines value 3 in decimal format
+var Three = New(3, 0)
+
+// Four defines value 4 in decimal format
+var Four = New(4, 0)
+
+// Five defines value 5 in decimal format
+var Five = New(5, 0)
+
+// Six defines value 6 in decimal format
+var Six = New(6, 0)
+
+// Seven defines value 6 in decimal format
+var Seven = New(7, 0)
+
+// Eight defines value 8 in decimal format
+var Eight = New(8, 0)
+
+// Nine defines value 9 in decimal format
+var Nine = New(9, 0)
+
+// Ten defines value 10 in decimal format
+var Ten = New(10, 0)
+
+// Eleven defines value 11 in decimal format
+var Eleven = New(11, 0)
+
+// Twelve defines value 12 in decimal format
+var Twelve = New(12, 0)
+
+// Thirteen defines value 13 in decimal format
+var Thirteen = New(13, 0)
+
+// Fourteen defines value 14 in decimal format
+var Fourteen = New(14, 0)
+
+// Fifteen defines value 15 in decimal format
+var Fifteen = New(15, 0)
+
+// Sixteen defines value 16 in decimal format
+var Sixteen = New(16, 0)
+
+// Seventeen defines value 17 in decimal format
+var Seventeen = New(17, 0)
+
+// Eighteen defines value 18 in decimal format
+var Eighteen = New(18, 0)
+
+// Nineteen defines value 19 in decimal format
+var Nineteen = New(19, 0)
+
+// Twenty defines value 20 in decimal format
+var Twenty = New(20, 0)
+
+// Thirty defines value 30 in decimal format
+var Thirty = New(30, 0)
+
+// Forty defines value 40 in decimal format
+var Forty = New(40, 0)
+
+// Fifty defines value 50 in decimal format
+var Fifty = New(50, 0)
+
+// Sixty defines value 60 in decimal format
+var Sixty = New(60, 0)
+
+// Seventy defines value 70 in decimal format
+var Seventy = New(70, 0)
+
+// Eighty defines value 80 in decimal format
+var Eighty = New(80, 0)
+
+// Ninty defines value 90 in decimal format
+var Ninty = New(90, 0)
+
+// Hundred defines value 100 in decimal format
+var Hundred = New(100, 0)
+
+// TwoHundred defines value 200 in decimal format
+var TwoHundred = New(200, 0)
+
+// ThreeHundred defines value 300 in decimal format
+var ThreeHundred = New(300, 0)
+
+// FourHundred defines value 400 in decimal format
+var FourHundred = New(400, 0)
+
+// FiveHundred defines value 500 in decimal format
+var FiveHundred = New(500, 0)
+
+// SixHundred defines value 600 in decimal format
+var SixHundred = New(600, 0)
+
+// SevenHundred defines value 700 in decimal format
+var SevenHundred = New(700, 0)
+
+// EightHundred defines value 800 in decimal format
+var EightHundred = New(800, 0)
+
+// NineHundred defines value 900 in decimal format
+var NineHundred = New(900, 0)
+
+// Thousand defines value 100 in decimal format
+var Thousand = New(1000, 0)

sqrt.go

@@ -0,0 +1,35 @@
+package decimal
+
+const sqrtMaxIter = 10000
+
+// Sqrt returns the square root of d, the result will have
+// DivisionPrecision digits after the decimal point.
+func (d Decimal) Sqrt() Decimal {
+	s, _ := d.SqrtRound(int32(DivisionPrecision))
+	return s
+}
+
+// SqrtRound returns the square root of d, the result will have
+// precision digits after the decimal point. The bool precise returns whether the precision was reached
+func (d Decimal) SqrtRound(precision int32) (Decimal, bool) {
+	if d.LessThanOrEqualZero() {
+		return Zero, false
+	}
+	cutoff := New(1, -precision)
+	lo := Zero
+	hi := d
+	var mid Decimal
+	for i := 0; i < sqrtMaxIter; i++ {
+		//mid = (lo+hi)/2;
+		mid = lo.Add(hi).DivRound(Two, precision)
+		if mid.Mul(mid).Sub(d).Abs().LessThan(cutoff) {
+			return mid, true
+		}
+		if mid.Mul(mid).GreaterThan(d) {
+			hi = mid
+		} else {
+			lo = mid
+		}
+	}
+	return mid, false
+}

sqrt_test.go

@@ -0,0 +1,24 @@
+package decimal
+
+import (
+	"testing"
+)
+
+func TestSqrt(t *testing.T) {
+	tables := []struct {
+		x Decimal
+		n Decimal
+	}{
+		{One, One},
+		{Four, Two},
+		{Sixteen, Four},
+		{Two, NewFromFloat(1.4142135623730951)},
+	}
+
+	for _, table := range tables {
+		result := table.x.Sqrt()
+		if result.NotEqual(table.n) {
+			t.Errorf("Sqrt of (%v) was incorrect, got: %v, want: %v.", table.x.String(), result.String(), table.n.String())
+		}
+	}
+}

zero.go

@@ -0,0 +1,31 @@
+package decimal
+
+// EqualZero returns whether the numbers represented by d equals zero.
+func (d Decimal) EqualZero() bool {
+	return d.Equal(Zero)
+}
+
+// NotZero returns whether d is not zero
+func (d Decimal) NotZero() bool {
+	return !d.EqualZero()
+}
+
+// GreaterThanZero (GT0) returns true when d is greater than zero.
+func (d Decimal) GreaterThanZero() bool {
+	return d.GreaterThan(Zero)
+}
+
+// GreaterThanOrEqualZero (GTE0) returns true when d is greater than or equal to zero.
+func (d Decimal) GreaterThanOrEqualZero() bool {
+	return d.GreaterThanOrEqual(Zero)
+}
+
+// LessThanZero returns true when d is less than zero.
+func (d Decimal) LessThanZero() bool {
+	return d.LessThan(Zero)
+}
+
+// LessThanOrEqualZero returns true when d is less than or equal to zero.
+func (d Decimal) LessThanOrEqualZero() bool {
+	return d.LessThanOrEqual(Zero)
+}