Merge aa070c4ec8 into 80ec940054

* Drop support for Go versions older than 1.10
* Remove 1.18 from test suite

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go: [ '1.7.x', '1.18', '1.19', '1.20', '1.21', '1.x' ]
+        go: [ '1.10.x', '1.19', '1.20', '1.21', '1.22', '1.x' ]
     name: Go ${{ matrix.go }}
     steps:
       - uses: actions/checkout@v4

README.md

@@ -22,7 +22,7 @@ Run `go get github.com/shopspring/decimal`
 
 ## Requirements 
 
-Decimal library requires Go version `>=1.7`
+Decimal library requires Go version `>=1.10`
 
 ## Usage
 
@@ -63,11 +63,6 @@ func main() {
 
 http://godoc.org/github.com/shopspring/decimal
 
-## Production Usage
-
-* [Spring](https://shopspring.com/), since August 14, 2014.
-* If you are using this in production, please let us know!
-
 ## FAQ
 
 #### Why don't you just use float64?

decimal.go

@@ -19,6 +19,7 @@ package decimal
 import (
 	"database/sql/driver"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"math"
 	"math/big"
@@ -130,6 +131,18 @@ func NewFromInt32(value int32) Decimal {
 	}
 }
 
+// NewFromUint64 converts an uint64 to Decimal.
+//
+// Example:
+//
+//	NewFromUint64(123).String() // output: "123"
+func NewFromUint64(value uint64) Decimal {
+	return Decimal{
+		value: new(big.Int).SetUint64(value),
+		exp:   0,
+	}
+}
+
 // NewFromBigInt returns a new Decimal from a big.Int, value * 10 ^ exp
 func NewFromBigInt(value *big.Int, exp int32) Decimal {
 	return Decimal{
@@ -1406,9 +1419,7 @@ func (d Decimal) IntPart() int64 {
 // BigInt returns integer component of the decimal as a BigInt.
 func (d Decimal) BigInt() *big.Int {
 	scaledD := d.rescale(0)
-	i := &big.Int{}
-	i.SetString(scaledD.String(), 10)
-	return i
+	return scaledD.value
 }
 
 // BigFloat returns decimal as BigFloat.
@@ -2322,3 +2333,59 @@ func (d Decimal) Tan() Decimal {
 	}
 	return y
 }
+
+// More math
+
+// Sqrt returns the square root of d, accurate to DivisionPrecision decimal places.
+// Sqrt is only valid for non-negative numbers; it will return an error otherwise.
+func (d Decimal) Sqrt() (Decimal, error) {
+	s, _, err := d.SqrtRound(int32(DivisionPrecision))
+	return s, err
+}
+
+// ErrImaginaryResult indicates an operation that would produce an imaginary result.
+var ErrImaginaryResult = errors.New("The result of this operation is imaginary.")
+
+// SqrtMaxIter sets a limit for number of iterations for the Sqrt function
+const SqrtMaxIter = 1000000
+
+// SqrtRound returns the square root of d, accurate to precision decimal places.
+// The bool precise returns whether the precision was achieved.
+// SqrtRound is only valid for non-negative numbers; it will return an error otherwise.
+func (d Decimal) SqrtRound(precision int32) (Decimal, bool, error) {
+	var (
+		maxError = New(1, -precision)
+		one      = NewFromFloat(1)
+		lo, hi   Decimal
+	)
+
+	// Handle cases where d < 0, d = 0, 0 < d < 1, and d > 1
+	if d.GreaterThanOrEqual(one) {
+		lo = Zero
+		hi = d
+	} else if d.Equal(one) {
+		return one, true, nil
+	} else if d.LessThan(Zero) {
+		return Zero, false, ErrImaginaryResult
+	} else if d.Equal(Zero) {
+		return Zero, true, nil
+	} else {
+		// d is between 0 and 1. Therefore, 0 < d < Sqrt(d) < 1.
+		lo = d
+		hi = one
+	}
+
+	var mid Decimal
+	for i := 0; i < SqrtMaxIter; i++ {
+		mid = lo.Add(hi).Div(New(2, 0)) //mid = (lo+hi)/2;
+		if mid.Mul(mid).Sub(d).Abs().LessThan(maxError) {
+			return mid, true, nil
+		}
+		if mid.Mul(mid).GreaterThan(d) {
+			hi = mid
+		} else {
+			lo = mid
+		}
+	}
+	return mid, false, nil
+}

decimal_test.go

@@ -476,10 +476,11 @@ func TestNewFromFloatWithExponent(t *testing.T) {
 
 func TestNewFromInt(t *testing.T) {
 	tests := map[int64]string{
-		0:                   "0",
-		1:                   "1",
-		323412345:           "323412345",
-		9223372036854775807: "9223372036854775807",
+		0:                    "0",
+		1:                    "1",
+		323412345:            "323412345",
+		9223372036854775807:  "9223372036854775807",
+		-9223372036854775808: "-9223372036854775808",
 	}
 
 	// add negatives
@@ -501,10 +502,11 @@ func TestNewFromInt(t *testing.T) {
 
 func TestNewFromInt32(t *testing.T) {
 	tests := map[int32]string{
-		0:          "0",
-		1:          "1",
-		323412345:  "323412345",
-		2147483647: "2147483647",
+		0:           "0",
+		1:           "1",
+		323412345:   "323412345",
+		2147483647:  "2147483647",
+		-2147483648: "-2147483648",
 	}
 
 	// add negatives
@@ -524,6 +526,25 @@ func TestNewFromInt32(t *testing.T) {
 	}
 }
 
+func TestNewFromUint64(t *testing.T) {
+	tests := map[uint64]string{
+		0:                    "0",
+		1:                    "1",
+		323412345:            "323412345",
+		9223372036854775807:  "9223372036854775807",
+		18446744073709551615: "18446744073709551615",
+	}
+
+	for input, s := range tests {
+		d := NewFromUint64(input)
+		if d.String() != s {
+			t.Errorf("expected %s, got %s (%s, %d)",
+				s, d.String(),
+				d.value.String(), d.exp)
+		}
+	}
+}
+
 func TestNewFromBigIntWithExponent(t *testing.T) {
 	type Inp struct {
 		val *big.Int
@@ -3460,6 +3481,40 @@ func TestAvg(t *testing.T) {
 	}
 }
 
+func TestSqrtRound(t *testing.T) {
+	i := NewFromFloat(-1)
+	if _, err := i.Sqrt(); err != ErrImaginaryResult {
+		t.Errorf("Square root of -1 should produce error")
+	}
+
+	var vals = map[string]string{
+		// value : Sqrt(value)
+		"0.0":       "0.0",
+		"0.002342":  "0.0483942145302514",
+		"1.0":       "1.0",
+		"3.0":       "1.7320508075688773",
+		"4.0":       "2.0",
+		"4.5":       "2.1213203435596426",
+		"3289854.0": "1813.7954680724064485",
+	}
+
+	for val, expected := range vals {
+		v, err := NewFromString(val)
+		if err != nil {
+			t.Errorf("error parsing test value into Decimal")
+		}
+
+		e, err := NewFromString(expected)
+		if err != nil {
+			t.Errorf("error parsing test expected value into Decimal")
+		}
+
+		if sqrt, err := v.Sqrt(); err != nil || !sqrt.Equal(e) {
+			t.Errorf("Square root of %s should be %s, not %s (error: %s)", v, e, sqrt, err)
+		}
+	}
+}
+
 func TestRoundBankAnomaly(t *testing.T) {
 	a := New(25, -1)
 	b := New(250, -2)

go.mod

@@ -1,3 +1,3 @@
 module github.com/shopspring/decimal
 
-go 1.7
+go 1.10