96 lines
3.1 KiB
C++
96 lines
3.1 KiB
C++
/*
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* Copyright (c) 2017, 2021, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "memory/allStatic.hpp"
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#include "metaprogramming/enableIf.hpp"
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#include "utilities/debug.hpp"
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#include "unittest.hpp"
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#include <type_traits>
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class EnableIfTest: AllStatic {
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class A: AllStatic {
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public:
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template <bool condition>
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static typename EnableIf<condition, char>::type test();
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template <bool condition>
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static typename EnableIf<!condition, long>::type test();
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};
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static const bool A_test_true_is_char = sizeof(A::test<true>()) == sizeof(char);
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STATIC_ASSERT(A_test_true_is_char);
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static const bool A_test_false_is_long = sizeof(A::test<false>()) == sizeof(long);
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STATIC_ASSERT(A_test_false_is_long);
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};
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template<typename T, ENABLE_IF(std::is_integral<T>::value)>
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static T sub1(T x) { return x - 1; }
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TEST(TestEnableIf, one_decl_and_def) {
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EXPECT_EQ(15, sub1(16));
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}
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template<typename T, ENABLE_IF(std::is_integral<T>::value)>
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static T sub2(T x);
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template<typename T, ENABLE_IF_SDEFN(std::is_integral<T>::value)>
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T sub2(T x) { return x - 2; }
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TEST(TestEnableIf, separate_decl_and_def) {
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EXPECT_EQ(14, sub2(16));
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}
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template<typename T>
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struct TestEnableIfNested {
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template<typename U, ENABLE_IF(std::is_integral<U>::value)>
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static U sub1(U x);
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};
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template<typename T>
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template<typename U, ENABLE_IF_SDEFN(std::is_integral<U>::value)>
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U TestEnableIfNested<T>::sub1(U x) { return x - 1; }
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TEST(TestEnableIf, nested_separate_decl_and_def) {
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EXPECT_EQ(15, TestEnableIfNested<void>::sub1(16));
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}
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// Demonstrate workaround for non-dependent condition.
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template<typename T>
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struct TestEnableIfNonDependent {
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// Dependent is used to make the ENABLE_IF condition dependent on
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// the type parameters for this function.
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template<typename Dependent = T, ENABLE_IF(std::is_same<int, Dependent>::value)>
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static T value() { return T{}; }
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static int instantiate() { return 5; }
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};
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TEST(TestEnableIf, non_dependent) {
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EXPECT_EQ(int{}, TestEnableIfNonDependent<int>::value());
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// This fails to compile if the ENABLE_IF for value() directly uses
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// T rather than indirectly via Dependent.
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EXPECT_EQ(5, TestEnableIfNonDependent<void>::instantiate());
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}
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