Fixed crash in builtin function right() (#1099)

* Fixed crash in builtin function right() * Fixed ut failure
vesoft-inc · Oct 17, 2019 · 6342c0a · 6342c0a
1 parent 85ae6e2
commit 6342c0a
Showing 1 changed file with 6 additions and 3 deletions.
diff --git a/src/common/filter/FunctionManager.cpp b/src/common/filter/FunctionManager.cpp
@@ -314,8 +314,8 @@ FunctionManager::FunctionManager() {
         attr.body_ = [] (const auto &args) {
             auto value = Expression::asString(args[0]);
             auto length = Expression::asInt(args[1]);
-            if (length < 0) {
-                length = 0;
+            if (length <= 0) {
+                return std::string();
             }
             return value.substr(0, length);
         };
@@ -328,7 +328,10 @@ FunctionManager::FunctionManager() {
             auto value  = Expression::asString(args[0]);
             auto length = Expression::asInt(args[1]);
             if (length <= 0) {
-                length = 0;
+                return std::string();
+            }
+            if (length > static_cast<int64_t>(value.size())) {
+                length = value.size();
             }
             return value.substr(value.size() - length);
         };