Added capacity to slice creation, when capacity is known (#516)

regexp.go

@@ -195,7 +195,7 @@ func (r *routeRegexp) Match(req *http.Request, match *RouteMatch) bool {
 
 // url builds a URL part using the given values.
 func (r *routeRegexp) url(values map[string]string) (string, error) {
-	urlValues := make([]interface{}, len(r.varsN))
+	urlValues := make([]interface{}, len(r.varsN), len(r.varsN))
 	for k, v := range r.varsN {
 		value, ok := values[v]
 		if !ok {

route.go

@@ -635,7 +635,7 @@ func (r *Route) GetQueriesRegexp() ([]string, error) {
 	if r.regexp.queries == nil {
 		return nil, errors.New("mux: route doesn't have queries")
 	}
-	var queries []string
+	queries := make([]string, 0, len(r.regexp.queries))
 	for _, query := range r.regexp.queries {
 		queries = append(queries, query.regexp.String())
 	}
@@ -654,7 +654,7 @@ func (r *Route) GetQueriesTemplates() ([]string, error) {
 	if r.regexp.queries == nil {
 		return nil, errors.New("mux: route doesn't have queries")
 	}
-	var queries []string
+	queries := make([]string, 0, len(r.regexp.queries))
 	for _, query := range r.regexp.queries {
 		queries = append(queries, query.template)
 	}