1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // UNSUPPORTED: c++98, c++03, c++11, c++14
11 
12 // <iterator>
13 // template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17
14 // template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17
15 // template <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17
16 
17 #include <iterator>
18 #include <cassert>
19 #include <vector>
20 #include <array>
21 #include <list>
22 #include <initializer_list>
23 
24 #include "test_macros.h"
25 
26 #if TEST_STD_VER > 14
27 #include <string_view>
28 #endif
29 
30 template<typename C>
test_const_container(const C & c)31 void test_const_container( const C& c )
32 {
33 //  Can't say noexcept here because the container might not be
34     assert ( std::empty(c)   == c.empty());
35 }
36 
37 template<typename T>
test_const_container(const std::initializer_list<T> & c)38 void test_const_container( const std::initializer_list<T>& c )
39 {
40     assert ( std::empty(c)   == (c.size() == 0));
41 }
42 
43 template<typename C>
test_container(C & c)44 void test_container( C& c )
45 {
46 //  Can't say noexcept here because the container might not be
47     assert ( std::empty(c)   == c.empty());
48 }
49 
50 template<typename T>
test_container(std::initializer_list<T> & c)51 void test_container( std::initializer_list<T>& c )
52 {
53     ASSERT_NOEXCEPT(std::empty(c));
54     assert ( std::empty(c)   == (c.size() == 0));
55 }
56 
57 template<typename T, size_t Sz>
test_const_array(const T (& array)[Sz])58 void test_const_array( const T (&array)[Sz] )
59 {
60     ASSERT_NOEXCEPT(std::empty(array));
61     assert (!std::empty(array));
62 }
63 
main()64 int main()
65 {
66     std::vector<int> v; v.push_back(1);
67     std::list<int>   l; l.push_back(2);
68     std::array<int, 1> a; a[0] = 3;
69     std::initializer_list<int> il = { 4 };
70 
71     test_container ( v );
72     test_container ( l );
73     test_container ( a );
74     test_container ( il );
75 
76     test_const_container ( v );
77     test_const_container ( l );
78     test_const_container ( a );
79     test_const_container ( il );
80 
81 #if TEST_STD_VER > 14
82     std::string_view sv{"ABC"};
83     test_container ( sv );
84     test_const_container ( sv );
85 #endif
86 
87     static constexpr int arrA [] { 1, 2, 3 };
88     test_const_array ( arrA );
89 }
90