From 393e705d5c6fb2bf86b35c86aa79412b39b61b91 Mon Sep 17 00:00:00 2001
From: Andrei Kurushin <ajax16384@gmail.com>
Date: Fri, 20 Jan 2017 02:08:39 +0300
Subject: [PATCH] refactor entry::dictionary_type (#1568)

consolidate conditional std::map string code
enable C++14 string_view std::map for VS2015
---
 include/libtorrent/entry.hpp | 28 +++++++++++++++++++++-------
 src/entry.cpp                | 22 ++++------------------
 2 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/include/libtorrent/entry.hpp b/include/libtorrent/entry.hpp
index 32ffd73dd..fadf57f31 100644
--- a/include/libtorrent/entry.hpp
+++ b/include/libtorrent/entry.hpp
@@ -83,9 +83,9 @@ namespace libtorrent
 #endif
 	struct bdecode_node;
 
-#if __cplusplus > 201103
 	namespace aux
 	{
+#if (__cplusplus > 201103) || (defined _MSC_VER && _MSC_VER >= 1900)
 		// this enables us to compare a string_view against the std::string that's
 		// held by the std::map
 		struct strview_less
@@ -95,8 +95,26 @@ namespace libtorrent
 			bool operator()(T1 const& rhs, T2 const& lhs) const
 			{ return rhs < lhs; }
 		};
-	};
+
+		template<class T> using map_string = std::map<std::string, T, aux::strview_less>;
+#else
+		template<class T>
+		struct map_string : std::map<std::string, T>
+		{
+			using base = std::map<std::string, T>;
+
+			typename base::iterator find(const string_view& key)
+			{
+				return this->base::find(key.to_string());
+			}
+
+			typename base::const_iterator find(const string_view& key) const
+			{
+				return this->base::find(key.to_string());
+			}
+		};
 #endif
+	}
 
 	// The ``entry`` class represents one node in a bencoded hierarchy. It works as a
 	// variant type, it can be either a list, a dictionary (``std::map``), an integer
@@ -108,11 +126,7 @@ namespace libtorrent
 		// the key is always a string. If a generic entry would be allowed
 		// as a key, sorting would become a problem (e.g. to compare a string
 		// to a list). The definition doesn't mention such a limit though.
-#if __cplusplus <= 201103
-		using dictionary_type = std::map<std::string, entry>;
-#else
-		using dictionary_type = std::map<std::string, entry, aux::strview_less>;
-#endif
+		using dictionary_type = aux::map_string<entry>;
 		using string_type = std::string;
 		using list_type = std::vector<entry>;
 		using integer_type = std::int64_t;
diff --git a/src/entry.cpp b/src/entry.cpp
index a4ca6fae4..f18e3903f 100644
--- a/src/entry.cpp
+++ b/src/entry.cpp
@@ -90,46 +90,32 @@ namespace libtorrent
 
 	entry& entry::operator[](string_view key)
 	{
-#if __cplusplus <= 201103
-		dictionary_type::iterator i = dict().find(key.to_string());
-#else
 		dictionary_type::iterator i = dict().find(key);
-#endif
 		if (i != dict().end()) return i->second;
-		dictionary_type::iterator ret = dict().insert(
-			std::make_pair(key.to_string(), entry())).first;
+		dictionary_type::iterator ret = dict().emplace(
+			std::piecewise_construct,
+			std::forward_as_tuple(key),
+			std::forward_as_tuple()).first;
 		return ret->second;
 	}
 
 	const entry& entry::operator[](string_view key) const
 	{
-#if __cplusplus <= 201103
-		dictionary_type::const_iterator i = dict().find(key.to_string());
-#else
 		dictionary_type::const_iterator i = dict().find(key);
-#endif
 		if (i == dict().end()) throw_error();
 		return i->second;
 	}
 
 	entry* entry::find_key(string_view key)
 	{
-#if __cplusplus <= 201103
-		dictionary_type::iterator i = dict().find(key.to_string());
-#else
 		dictionary_type::iterator i = dict().find(key);
-#endif
 		if (i == dict().end()) return nullptr;
 		return &i->second;
 	}
 
 	entry const* entry::find_key(string_view key) const
 	{
-#if __cplusplus <= 201103
-		dictionary_type::const_iterator i = dict().find(key.to_string());
-#else
 		dictionary_type::const_iterator i = dict().find(key);
-#endif
 		if (i == dict().end()) return nullptr;
 		return &i->second;
 	}