vm: sqlvm: refine after updating dexon-foundation/decimal

Refine behaviors:
1. Check decimal.NewFromString by type instead of string compare.
2. Use Rescale in DecimalEncode.

2 files changed, 4 insertions, 11 deletions

diff --git a/core/vm/sqlvm/ast/types.go b/core/vm/sqlvm/ast/types.go
index 53f3217a0..975fd81ba 100644
--- a/core/vm/sqlvm/ast/types.go
+++ b/core/vm/sqlvm/ast/types.go
@@ -15,7 +15,6 @@ import (
 
 var (
 	bigIntOne = big.NewInt(1)
-	bigIntTen = big.NewInt(10)
 )
 
 // BoolValue represents a boolean value used by SQL three-valued logic.
@@ -304,15 +303,9 @@ func (dt DataType) GetMinMax() (decimal.Decimal, decimal.Decimal, bool) {
 	return pair.Min, pair.Max, ok
 }
 
-func decimalToBig(d decimal.Decimal) (b *big.Int) {
-	if exponent := int64(d.Exponent()); exponent >= 0 {
-		exp := new(big.Int).Exp(bigIntTen, big.NewInt(exponent), nil)
-		b = new(big.Int).Mul(d.Coefficient(), exp)
-	} else {
-		exp := new(big.Int).Exp(bigIntTen, big.NewInt(-exponent), nil)
-		b = new(big.Int).Div(d.Coefficient(), exp)
-	}
-	return
+func decimalToBig(d decimal.Decimal) *big.Int {
+	d = d.Rescale(0)
+	return d.Coefficient()
 }
 
 // Don't handle overflow here.
diff --git a/core/vm/sqlvm/ast/types_test.go b/core/vm/sqlvm/ast/types_test.go
index accbbe741..0973ba92a 100644
--- a/core/vm/sqlvm/ast/types_test.go
+++ b/core/vm/sqlvm/ast/types_test.go
@@ -156,7 +156,7 @@ func (s *TypesTestSuite) TestEncodeAndDecodeDecimal() {
 }
 
 func (s *TypesTestSuite) TestDataTypeGetMinMax() {
-	decAddressMax := decimal.New(2, 0).Pow(decimal.New(common.AddressLength*8, 0)).Sub(dec.One)
+	decAddressMax := decimal.Two.Pow(decimal.New(common.AddressLength*8, 0)).Sub(decimal.One)
 	testcases := []struct {
 		Name     string
 		In       DataType