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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/Pair.h"
#include "mozilla/TypeTraits.h"
using mozilla::IsSame;
using mozilla::MakePair;
using mozilla::Pair;
// Sizes aren't part of the guaranteed Pair interface, but we want to verify our
// attempts at compactness through EBO are moderately functional, *somewhere*.
#define INSTANTIATE(T1, T2, name, size) \
Pair<T1, T2> name##_1(T1(0), T2(0)); \
static_assert(sizeof(name##_1.first()) > 0, \
"first method should work on Pair<" #T1 ", " #T2 ">"); \
static_assert(sizeof(name##_1.second()) > 0, \
"second method should work on Pair<" #T1 ", " #T2 ">"); \
static_assert(sizeof(name##_1) == (size), \
"Pair<" #T1 ", " #T2 "> has an unexpected size"); \
Pair<T2, T1> name##_2(T2(0), T1(0)); \
static_assert(sizeof(name##_2.first()) > 0, \
"first method should work on Pair<" #T2 ", " #T1 ">"); \
static_assert(sizeof(name##_2.second()) > 0, \
"second method should work on Pair<" #T2 ", " #T1 ">"); \
static_assert(sizeof(name##_2) == (size), \
"Pair<" #T2 ", " #T1 "> has an unexpected size");
static constexpr size_t sizemax(size_t a, size_t b)
{
return (a > b) ? a : b;
}
INSTANTIATE(int, int, prim1, 2 * sizeof(int));
INSTANTIATE(int, long, prim2, sizeof(long) + sizemax(sizeof(int), alignof(long)));
struct EmptyClass { explicit EmptyClass(int) {} };
struct NonEmpty { char mC; explicit NonEmpty(int) {} };
INSTANTIATE(int, EmptyClass, both1, sizeof(int));
INSTANTIATE(int, NonEmpty, both2, sizeof(int) + alignof(int));
INSTANTIATE(EmptyClass, NonEmpty, both3, 1);
struct A { char dummy; explicit A(int) {} };
struct B : A { explicit B(int aI) : A(aI) {} };
INSTANTIATE(A, A, class1, 2);
INSTANTIATE(A, B, class2, 2);
INSTANTIATE(A, EmptyClass, class3, 1);
struct OtherEmpty : EmptyClass { explicit OtherEmpty(int aI) : EmptyClass(aI) {} };
// C++11 requires distinct objects of the same type, within the same "most
// derived object", to have different addresses. Pair allocates its elements as
// two bases, a base and a member, or two members. If the two elements have
// non-zero size or are unrelated, no big deal. But if they're both empty and
// related, something -- possibly both -- must be inflated. Exactly which are
// inflated depends which PairHelper specialization is used. We could
// potentially assert something about size for this case, but whatever we could
// assert would be very finicky. Plus it's two empty classes -- hardly likely.
// So don't bother trying to assert anything about this case.
//INSTANTIATE(EmptyClass, OtherEmpty, class4, ...something finicky...);
int
main()
{
A a(0);
B b(0);
const A constA(0);
const B constB(0);
// Check that MakePair generates Pair objects of the correct types.
static_assert(IsSame<decltype(MakePair(A(0), B(0))), Pair<A, B>>::value,
"MakePair should strip rvalue references");
static_assert(IsSame<decltype(MakePair(a, b)), Pair<A, B>>::value,
"MakePair should strip lvalue references");
static_assert(IsSame<decltype(MakePair(constA, constB)), Pair<A, B>>::value,
"MakePair should strip CV-qualifiers");
// Check that copy assignment and move assignment work.
a = constA;
a = A(0);
return 0;
}
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