From 60d62c767be3576cb674a817b90028951d6ee3b0 Mon Sep 17 00:00:00 2001
From: "Brad Payne (Vir Linden)" <vir@lindenlab.com>
Date: Tue, 16 Mar 2021 16:18:56 +0100
Subject: SL-14999 - cppfeatures test file for examples and compiler
 conformance verification

---
 indra/newview/CMakeLists.txt             |   4 +
 indra/newview/tests/cppfeatures_test.cpp | 127 +++++++++++++++++++++++++++++++
 2 files changed, 131 insertions(+)
 create mode 100644 indra/newview/tests/cppfeatures_test.cpp

diff --git a/indra/newview/CMakeLists.txt b/indra/newview/CMakeLists.txt
index 3439951e80..9c11f8aa87 100644
--- a/indra/newview/CMakeLists.txt
+++ b/indra/newview/CMakeLists.txt
@@ -2520,6 +2520,10 @@ if (LL_TESTS)
     ${BOOST_CONTEXT_LIBRARY}
   )
 
+  LL_ADD_INTEGRATION_TEST(cppfeatures
+    ""
+    "${test_libs}"
+    )
   LL_ADD_INTEGRATION_TEST(llsechandler_basic
     llsechandler_basic.cpp
     "${test_libs}"
diff --git a/indra/newview/tests/cppfeatures_test.cpp b/indra/newview/tests/cppfeatures_test.cpp
new file mode 100644
index 0000000000..15aa1cd6d6
--- /dev/null
+++ b/indra/newview/tests/cppfeatures_test.cpp
@@ -0,0 +1,127 @@
+/**
+ * @file cppfeatures_test
+ * @author Vir
+ * @date 2021-03
+ * @brief cpp features
+ *
+ * $LicenseInfo:firstyear=2021&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2021, Linden Research, Inc.
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * 
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+// Tests related to newer C++ features, for verifying support across compilers and platforms
+
+#include "linden_common.h"
+#include "../test/lltut.h"
+
+namespace tut
+{
+
+struct cpp_features_test {};
+typedef test_group<cpp_features_test> cpp_features_test_t;
+typedef cpp_features_test_t::object cpp_features_test_object_t;
+tut::cpp_features_test_t tut_cpp_features_test("LLCPPFeatures");
+
+// bracket initializers
+// Can initialize containers or values using curly brackets
+template<> template<>
+void cpp_features_test_object_t::test<1>()
+{
+	S32 explicit_val{3};
+	ensure(explicit_val==3);
+
+	S32 default_val{};
+	ensure(default_val==0);
+	
+	std::vector<S32> fibs{1,1,2,3,5};
+	ensure(fibs[4]==5);
+}
+
+// auto
+//
+// https://en.cppreference.com/w/cpp/language/auto
+// 
+// Can use auto in place of a more complex type specification, if the compiler can infer the type
+template<> template<>
+void cpp_features_test_object_t::test<2>()
+{
+	std::vector<S32> numbers{3,6,9};
+
+	// auto element
+	auto& aval = numbers[1];
+	ensure("auto element", aval==6);
+
+	// auto iterator (non-const)
+	auto it = numbers.rbegin();
+	*it += 1;
+	S32 val = *it;
+	ensure("auto iterator", val==10);
+}
+
+// range for
+//
+// https://en.cppreference.com/w/cpp/language/range-for
+//
+// Can iterate over containers without explicit iterator
+template<> template<>
+void cpp_features_test_object_t::test<3>()
+{
+
+	// Traditional iterator for with container
+	//
+	// Problems:
+	// * Have to create a new variable for the iterator, which is unrelated to the problem you're trying to solve.
+	// * Redundant and somewhat fragile. Have to make sure begin() and end() are both from the right container.
+	std::vector<S32> numbers{3,6,9};
+	for (auto it = numbers.begin(); it != numbers.end(); ++it)
+	{
+		auto& n = *it;
+		n *= 2;
+	}
+	ensure("iterator for vector", numbers[2]==18);
+
+	// Range for with container
+	//
+	// Under the hood, this is doing the same thing as the traditional
+	// for loop above. Still uses begin() and end() but you don't have
+	// to access them directly.
+	std::vector<S32> numbersb{3,6,9};
+	for (auto& n: numbersb)
+	{
+		n *= 2;
+	}
+	ensure("range for vector", numbersb[2]==18);
+
+	// Range for over a C-style array.
+	//
+	// This is handy because the language determines the range automatically.
+	// Getting this right manually is a little trickier.
+	S32 pows[] = {1,2,4,8,16};
+	S32 sum{};
+	for (const auto& v: pows)
+	{
+		sum += v;
+	}
+	ensure("for C-array", sum==31);
+}
+
+
+
+}
-- 
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