add upstream 11.20

1 files changed, 14 insertions, 1 deletions

diff --git a/zen/stl_tools.h b/zen/stl_tools.h
index c2e8eff3..0d359641 100644
--- a/zen/stl_tools.h
+++ b/zen/stl_tools.h
@@ -290,13 +290,26 @@ Num hashArray(ByteIterator first, ByteIterator last)
 
 struct StringHash //support for custom string classes with std::unordered_set/map
 {
+    using is_transparent = int; //allow heterogenous lookup!
+
     template <class String>
     size_t operator()(const String& str) const
     {
-        const auto* strFirst = strBegin(str);
+        const auto* const strFirst = strBegin(str);
         return hashArray<size_t>(strFirst, strFirst + strLength(str));
     }
 };
+
+struct StringEqual
+{
+    using is_transparent = int; //allow heterogenous lookup!
+
+    template <class String1, class String2>
+    bool operator()(const String1& lhs, const String2& rhs) const
+    {
+        return equalString(lhs, rhs);
+    }
+};
 }
 
 #endif //STL_TOOLS_H_84567184321434