fix: improve bigIntToTwosComplement to handle large values and normalize byte representation

RaphDal · RaphDal · commit 36d707087bc9 · 2025-11-11T09:40:06.000+01:00
diff --git a/decimal.go b/decimal.go
@@ -154,11 +154,12 @@ func bigIntToTwosComplement(value *big.Int) ([32]byte, uint8, error) {
 		return [32]byte{0}, 31, nil
 	}
 	if value.Sign() > 0 {
-		bytes := value.Bytes()
-		if bytes[0]&0x80 != 0 {
-			bytes = append([]byte{0x00}, bytes...)
+		if value.BitLen() > 255 {
+			return [32]byte{}, 0, fmt.Errorf("decimal unscaled value exceeds 32 bytes")
 		}
-		return normalizeTwosComplement(bytes)
+		buf := [32]byte{}
+		value.FillBytes(buf[:])
+		return buf, uint8(trimTwosComplement(buf[:])), nil
 	}
 
 	bitLen := value.BitLen()

Original file line number	Diff line number	Diff line change
`@@ -154,11 +154,12 @@ func bigIntToTwosComplement(value *big.Int) ([32]byte, uint8, error) {`
`154`	`154`	`return [32]byte{0}, 31, nil`
`155`	`155`	`}`
`156`	`156`	`if value.Sign() > 0 {`
`157`		`- bytes := value.Bytes()`
`158`		`- if bytes[0]&0x80 != 0 {`
`159`		`- bytes = append([]byte{0x00}, bytes...)`
	`157`	`+ if value.BitLen() > 255 {`
	`158`	`+ return [32]byte{}, 0, fmt.Errorf("decimal unscaled value exceeds 32 bytes")`
`160`	`159`	`}`
`161`		`- return normalizeTwosComplement(bytes)`
	`160`	`+ buf := [32]byte{}`
	`161`	`+ value.FillBytes(buf[:])`
	`162`	`+ return buf, uint8(trimTwosComplement(buf[:])), nil`
`162`	`163`	`}`
`163`	`164`
`164`	`165`	`bitLen := value.BitLen()`