From 001169749289209823c5f567afed1f7e8f5c1ef0 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Thu, 28 Apr 2022 20:42:48 +0300
Subject: [PATCH] Add hash_value (refs #110)

---
 include/boost/core/detail/string_view.hpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/boost/core/detail/string_view.hpp b/include/boost/core/detail/string_view.hpp
index c742198..14c7edc 100644
--- a/include/boost/core/detail/string_view.hpp
+++ b/include/boost/core/detail/string_view.hpp
@@ -38,8 +38,12 @@
 namespace boost
 {
 
+// forward declaration of boost::basic_string_view from Utility
 template<class Ch, class Tr> class basic_string_view;
 
+// forward declaration of boost::hash_range from ContainerHash
+template<class It> std::size_t hash_range( It, It );
+
 namespace core
 {
 namespace detail
@@ -1161,6 +1165,11 @@ public:
     }
 
 #endif
+
+    inline friend std::size_t hash_value( basic_string_view const& sv )
+    {
+        return boost::hash_range( sv.begin(), sv.end() );
+    }
 };
 
 // stream inserter