fix leaks and add one more NULL check

Author: weltling

ext/pdo_dblib/dblib_stmt.c

@@ -104,19 +104,33 @@ static int pdo_dblib_stmt_cursor_closer(pdo_stmt_t *stmt TSRMLS_DC)
 	dbcancel(H->link);
 
 	if (stmt->columns) {
+		int i = 0;
+		for (; i < stmt->column_count; i++) {
+			if (stmt->columns[i].name) {
+				efree(stmt->columns[i].name);
+			}
+		}
 		efree(stmt->columns); 
 		stmt->columns = NULL;
 	}
-	
+
 	return 1;
 }
 
 static int pdo_dblib_stmt_dtor(pdo_stmt_t *stmt TSRMLS_DC)
 {
 	pdo_dblib_stmt *S = (pdo_dblib_stmt*)stmt->driver_data;
 
-	efree(stmt->columns); 
-	stmt->columns = NULL;
+	if (stmt->columns) {
+		int i = 0;
+		for (; i < stmt->column_count; i++) {
+			if (stmt->columns[i].name) {
+				efree(stmt->columns[i].name);
+			}
+		}
+		efree(stmt->columns); 
+		stmt->columns = NULL;
+	}
 
 	efree(S);