Merge 49883997d8 into 547861c49b

.github/workflows/ci.yml

@@ -1,15 +1,11 @@
 name: ci
-on:
-  push:
-    branches:
-      - master
-  pull_request:
+on: [push]
 jobs:
   ci-job:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go: [ '1.10.x', '1.19', '1.20', '1.21', '1.22', '1.x' ]
+        go: [ '1.7.x', '1.18', '1.19', '1.20', '1.21', '1.x' ]
     name: Go ${{ matrix.go }}
     steps:
       - uses: actions/checkout@v4

README.md

@@ -24,7 +24,7 @@ Run `go get github.com/shopspring/decimal`
 
 ## Requirements 
 
-Decimal library requires Go version `>=1.10`
+Decimal library requires Go version `>=1.7`
 
 ## Usage
 

decimal.go

@@ -1224,33 +1224,14 @@ func (d Decimal) Ln(precision int32) (Decimal, error) {
 }
 
 // NumDigits returns the number of digits of the decimal coefficient (d.Value)
+// Note: Current implementation is extremely slow for large decimals and/or decimals with large fractional part
 func (d Decimal) NumDigits() int {
-	if d.value == nil {
-		return 1
+	d.ensureInitialized()
+	// Note(mwoss): It can be optimized, unnecessary cast of big.Int to string
+	if d.IsNegative() {
+		return len(d.value.String()) - 1
 	}
-
-	if d.value.IsInt64() {
-		i64 := d.value.Int64()
-		// restrict fast path to integers with exact conversion to float64
-		if i64 <= (1<<53) && i64 >= -(1<<53) {
-			if i64 == 0 {
-				return 1
-			}
-			return int(math.Log10(math.Abs(float64(i64)))) + 1
-		}
-	}
-
-	estimatedNumDigits := int(float64(d.value.BitLen()) / math.Log2(10))
-
-	// estimatedNumDigits (lg10) may be off by 1, need to verify
-	digitsBigInt := big.NewInt(int64(estimatedNumDigits))
-	errorCorrectionUnit := digitsBigInt.Exp(tenInt, digitsBigInt, nil)
-
-	if d.value.CmpAbs(errorCorrectionUnit) >= 0 {
-		return estimatedNumDigits + 1
-	}
-
-	return estimatedNumDigits
+	return len(d.value.String())
 }
 
 // IsInteger returns true when decimal can be represented as an integer value, otherwise, it returns false.
@@ -1406,7 +1387,9 @@ 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)
-	return scaledD.value
+	i := &big.Int{}
+	i.SetString(scaledD.String(), 10)
+	return i
 }
 
 // BigFloat returns decimal as BigFloat.

decimal_bench_test.go

@@ -121,34 +121,6 @@ func BenchmarkDecimal_RoundCash_Five(b *testing.B) {
 	}
 }
 
-func numDigits(b *testing.B, want int, val Decimal) {
-	b.Helper()
-	for i := 0; i < b.N; i++ {
-		if have := val.NumDigits(); have != want {
-			b.Fatalf("\nHave: %d\nWant: %d", have, want)
-		}
-	}
-}
-
-func BenchmarkDecimal_NumDigits10(b *testing.B) {
-	numDigits(b, 10, New(3478512345, -3))
-}
-
-func BenchmarkDecimal_NumDigits100(b *testing.B) {
-	s := make([]byte, 102)
-	for i := range s {
-		s[i] = byte('0' + i%10)
-	}
-	s[0] = '-'
-	s[100] = '.'
-	d, err := NewFromString(string(s))
-	if err != nil {
-		b.Log(d)
-		b.Error(err)
-	}
-	numDigits(b, 100, d)
-}
-
 func Benchmark_Cmp(b *testing.B) {
 	decimals := DecimalSlice([]Decimal{})
 	for i := 0; i < 1000000; i++ {
@@ -160,7 +132,7 @@ func Benchmark_Cmp(b *testing.B) {
 	}
 }
 
-func BenchmarkDecimal_Add_different_precision(b *testing.B) {
+func Benchmark_decimal_Decimal_Add_different_precision(b *testing.B) {
 	d1 := NewFromFloat(1000.123)
 	d2 := NewFromFloat(500).Mul(NewFromFloat(0.12))
 
@@ -171,7 +143,7 @@ func BenchmarkDecimal_Add_different_precision(b *testing.B) {
 	}
 }
 
-func BenchmarkDecimal_Sub_different_precision(b *testing.B) {
+func Benchmark_decimal_Decimal_Sub_different_precision(b *testing.B) {
 	d1 := NewFromFloat(1000.123)
 	d2 := NewFromFloat(500).Mul(NewFromFloat(0.12))
 
@@ -182,7 +154,7 @@ func BenchmarkDecimal_Sub_different_precision(b *testing.B) {
 	}
 }
 
-func BenchmarkDecimal_Add_same_precision(b *testing.B) {
+func Benchmark_decimal_Decimal_Add_same_precision(b *testing.B) {
 	d1 := NewFromFloat(1000.123)
 	d2 := NewFromFloat(500.123)
 
@@ -193,7 +165,7 @@ func BenchmarkDecimal_Add_same_precision(b *testing.B) {
 	}
 }
 
-func BenchmarkDecimal_Sub_same_precision(b *testing.B) {
+func Benchmark_decimal_Decimal_Sub_same_precision(b *testing.B) {
 	d1 := NewFromFloat(1000.123)
 	d2 := NewFromFloat(500.123)
 

go.mod

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