diff --git a/args.go b/args.go
index f81ebd7..4ed61c4 100644
--- a/args.go
+++ b/args.go
@@ -391,8 +391,8 @@ func decodeArgAppend(dst, src []byte, decodePlus bool) []byte {
 			if i+2 >= n {
 				return append(dst, src[i:]...)
 			}
-			x1 := unhex(src[i+1])
-			x2 := unhex(src[i+2])
+			x1 := hexbyte2int(src[i+1])
+			x2 := hexbyte2int(src[i+2])
 			if x1 < 0 || x2 < 0 {
 				dst = append(dst, c)
 			} else {
diff --git a/bytesconv.go b/bytesconv.go
index df17b5c..e07fdcd 100644
--- a/bytesconv.go
+++ b/bytesconv.go
@@ -232,19 +232,6 @@ func unsafeBytesToStr(b []byte) string {
 	return *(*string)(unsafe.Pointer(&b))
 }
 
-func unhex(c byte) int {
-	if c >= '0' && c <= '9' {
-		return int(c - '0')
-	}
-	if c >= 'a' && c <= 'f' {
-		return 10 + int(c-'a')
-	}
-	if c >= 'A' && c <= 'F' {
-		return 10 + int(c-'A')
-	}
-	return -1
-}
-
 func appendQuotedArg(dst, v []byte) []byte {
 	for _, c := range v {
 		if c >= '0' && c <= '9' || c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' || c == '/' || c == '.' {