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/**
* @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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