Fix typo in equal_range

fix #688

CHANGELOG.md

@@ -1,6 +1,7 @@
 Version 90:
 
 * Fix websocket read of zero length message
+* Fix typo in equal_range
 
 --------------------------------------------------------------------------------
 

include/boost/beast/http/impl/fields.ipp

@@ -723,11 +723,13 @@ basic_fields<Allocator>::
 equal_range(string_view name) const ->
     std::pair<const_iterator, const_iterator>
 {
-    auto const result =
+    auto result =
         set_.equal_range(name, key_compare{});
+    if(result.first == result.second)
+        return {list_.end(), list_.end()};
     return {
-        list_.iterator_to(result->first),
+        list_.iterator_to(*result.first),
-        list_.iterator_to(result->second)};
+        ++list_.iterator_to(*(--result.second))};
 }
 
 //------------------------------------------------------------------------------

test/http/fields.cpp

@@ -403,6 +403,23 @@ public:
             BEAST_EXPECT(f.count("dd") == 1);
             BEAST_EXPECT(f["dd"] == "-");
         }
+
+        // equal_range
+        {
+            fields f;
+            f.insert("E", 1);
+            f.insert("B", 2);
+            f.insert("D", 3);
+            f.insert("B", 4);
+            f.insert("C", 5);
+            f.insert("B", 6);
+            f.insert("A", 7);
+            auto const rng = f.equal_range("B");
+            BEAST_EXPECT(std::distance(rng.first, rng.second) == 3);
+            BEAST_EXPECT(std::next(rng.first, 0)->value() == "2");
+            BEAST_EXPECT(std::next(rng.first, 1)->value() == "4");
+            BEAST_EXPECT(std::next(rng.first, 2)->value() == "6");
+        }
     }
 
     struct sized_body