reflectx: use github.com/scylladb/go-reflectx

Signed-off-by: Michał Matczuk <michal@scylladb.com>

mapper.go

@@ -5,40 +5,11 @@
 package gocqlx
 
 import (
-	"fmt"
-	"unicode"
-
-	"github.com/scylladb/gocqlx/reflectx"
+	"github.com/scylladb/go-reflectx"
 )
 
 // DefaultMapper uses `db` tag and automatically converts struct field names to
 // snake case. It can be set to whatever you want, but it is encouraged to be
 // set before gocqlx is used as name-to-field mappings are cached after first
 // use on a type.
-var DefaultMapper = reflectx.NewMapperFunc("db", snakeCase)
-
-// snakeCase converts camel case to snake case.
-func snakeCase(s string) string {
-	buf := []byte(s)
-	out := make([]byte, 0, len(buf)+3)
-
-	l := len(buf)
-	for i := 0; i < l; i++ {
-		if !(allowedBindRune(buf[i]) || buf[i] == '_') {
-			panic(fmt.Sprint("not allowed name ", s))
-		}
-
-		b := rune(buf[i])
-
-		if unicode.IsUpper(b) {
-			if i > 0 && buf[i-1] != '_' && (unicode.IsLower(rune(buf[i-1])) || (i+1 < l && unicode.IsLower(rune(buf[i+1])))) {
-				out = append(out, '_')
-			}
-			b = unicode.ToLower(b)
-		}
-
-		out = append(out, byte(b))
-	}
-
-	return string(out)
-}
+var DefaultMapper = reflectx.NewMapperFunc("db", reflectx.CamelToSnakeASCII)