From 46e1696316e2d33c0198af2138ab481d985439f0 Mon Sep 17 00:00:00 2001
From: "Philipp A. Hartmann" <pah@qo.cx>
Date: Mon, 13 Jul 2015 09:35:15 +0200
Subject: [PATCH] add free inline `swap` functions

---
 include/rapidjson/document.h   |  4 ++++
 test/unittest/documenttest.cpp | 12 ++++++++++++
 test/unittest/valuetest.cpp    |  6 ++++++
 3 files changed, 22 insertions(+)

diff --git a/include/rapidjson/document.h b/include/rapidjson/document.h
index 3496c2b..007fa94 100644
--- a/include/rapidjson/document.h
+++ b/include/rapidjson/document.h
@@ -660,6 +660,8 @@ public:
         return *this;
     }
 
+    friend inline void swap(GenericValue& a, GenericValue& b) RAPIDJSON_NOEXCEPT { a.Swap(b); }
+
     //! Prepare Value for move semantics
     /*! \return *this */
     GenericValue& Move() RAPIDJSON_NOEXCEPT { return *this; }
@@ -1818,6 +1820,8 @@ public:
         return *this;
     }
 
+    friend inline void swap(GenericDocument& a, GenericDocument& b) RAPIDJSON_NOEXCEPT { a.Swap(b); }
+
     //!@name Parse from stream
     //!@{
 
diff --git a/test/unittest/documenttest.cpp b/test/unittest/documenttest.cpp
index 3db7cd8..810a99c 100644
--- a/test/unittest/documenttest.cpp
+++ b/test/unittest/documenttest.cpp
@@ -19,6 +19,7 @@
 #include "rapidjson/encodedstream.h"
 #include "rapidjson/stringbuffer.h"
 #include <sstream>
+#include <algorithm>
 
 using namespace rapidjson;
 
@@ -223,6 +224,17 @@ TEST(Document, Swap) {
     Document().Swap(d2);
     EXPECT_TRUE(d2.IsNull());
     EXPECT_NE(&d2.GetAllocator(), &a);
+
+    // testing std::swap compatibility
+    d1.SetBool(true);
+    using std::swap;
+    swap(d1, d2);
+    EXPECT_TRUE(d1.IsNull());
+    EXPECT_TRUE(d2.IsTrue());
+
+    swap(o, d2);
+    EXPECT_TRUE(o.IsTrue());
+    EXPECT_TRUE(d2.IsArray());
 }
 
 
diff --git a/test/unittest/valuetest.cpp b/test/unittest/valuetest.cpp
index f14669a..900783c 100644
--- a/test/unittest/valuetest.cpp
+++ b/test/unittest/valuetest.cpp
@@ -272,6 +272,12 @@ TEST(Value, Swap) {
     EXPECT_TRUE(v1.IsObject());
     EXPECT_TRUE(v2.IsInt());
     EXPECT_EQ(1234, v2.GetInt());
+
+    // testing std::swap compatibility
+    using std::swap;
+    swap(v1, v2);
+    EXPECT_TRUE(v1.IsInt());
+    EXPECT_TRUE(v2.IsObject());
 }
 
 TEST(Value, Null) {