1 // PR c++/84684
2 // { dg-options -std=c++17 }
3
4 typedef decltype (sizeof (0)) size_t;
5
6 namespace std {
7 template<class _E>
8 struct initializer_list
9 {
10 typedef _E value_type;
11 typedef const _E& reference;
12 typedef const _E& const_reference;
13 typedef size_t size_type;
14 typedef const _E* iterator;
15 typedef const _E* const_iterator;
16 iterator _M_array;
17 size_type _M_len;
initializer_listinitializer_list18 constexpr initializer_list(const_iterator __a, size_type __l) : _M_array(__a), _M_len(__l) { }
initializer_listinitializer_list19 constexpr initializer_list() noexcept : _M_array(0), _M_len(0) { }
sizeinitializer_list20 constexpr size_type size() const noexcept { return _M_len; }
begininitializer_list21 constexpr const_iterator begin() const noexcept { return _M_array; }
endinitializer_list22 constexpr const_iterator end() const noexcept { return begin() + size(); }
23 };
24 }
25
26 template <typename E, size_t N>
27 struct array
28 {
29 constexpr E &operator[](size_t n) noexcept { return elems[n]; }
30 constexpr const E &operator[](size_t n) const noexcept { return elems[n]; }
sizearray31 constexpr size_t size() const { return N; }
32 E elems[N];
33 };
34
35 template<typename T>
36 constexpr
37 inline T
max(std::initializer_list<T> i)38 max (std::initializer_list<T> i)
39 {
40 const T *b = i.begin ();
41 const T *e = i.end ();
42 if (b == e) return *b;
43 const T *r = b;
44 while (++b != e)
45 if (*r < *b)
46 r = b;
47 return *r;
48 }
49
50 template <typename alphabet_type>
to_char(alphabet_type const alph)51 constexpr char to_char(alphabet_type const alph)
52 {
53 return alph.to_char();
54 }
55
56 template <typename ...alphabet_types>
57 struct union_composition
58 {
59 static constexpr size_t value_size = (alphabet_types::value_size + ... );
60 unsigned char _value;
61 template <size_t fixed_size, typename alphabet_t>
value_to_char_helperunion_composition62 static constexpr auto value_to_char_helper(alphabet_t alphabet)
63 {
64 array<char, fixed_size> value_to_char{};
65 for (size_t i = 0u; i < alphabet_t::value_size; ++i)
66 value_to_char[i] = to_char(alphabet.assign_rank(i));
67 return value_to_char;
68 }
69
make_value_to_charunion_composition70 static constexpr auto make_value_to_char()
71 {
72 constexpr auto N = sizeof...(alphabet_types);
73 constexpr array<size_t, N> alphabet_sizes { alphabet_types::value_size... };
74 constexpr size_t fixed_size = max({alphabet_types::value_size...});
75 array value_to_char_tables = array<array<char, fixed_size>, N> {
76 value_to_char_helper<fixed_size>(alphabet_types{})...
77 };
78 array<char, value_size> value_to_char{};
79 for (size_t i = 0u, value = 0u; i < N; ++i)
80 for (size_t k = 0u; k < alphabet_sizes[i]; ++k, ++value)
81 value_to_char[value] = value_to_char_tables[i][k];
82 return value_to_char;
83 }
84 };
85
86 struct gap
87 {
to_chargap88 constexpr char to_char() const noexcept { return '-'; }
assign_rankgap89 constexpr gap & assign_rank([[maybe_unused]] bool const i) noexcept { return *this; }
90 static constexpr size_t value_size{1};
91 };
92
93 struct dna4
94 {
to_chardna495 constexpr char to_char() const noexcept { return value_to_char[_value]; }
assign_rankdna496 constexpr dna4 & assign_rank(unsigned char const c) { _value = c; return *this; }
97 static constexpr size_t value_size{4};
98 static constexpr char value_to_char[value_size] { 'A', 'C', 'G', 'T' };
99 unsigned char _value;
100 };
101
102 struct dna5
103 {
to_chardna5104 constexpr char to_char() const noexcept { return value_to_char[_value]; }
assign_rankdna5105 constexpr dna5 & assign_rank(unsigned char const c) { _value = c; return *this; }
106 static constexpr size_t value_size{5};
107 static constexpr char value_to_char[value_size] { 'A', 'C', 'G', 'T', 'N' };
108 unsigned char _value;
109 };
110
111 constexpr array value_to_char1 = union_composition<dna4>::make_value_to_char();
112 static_assert(value_to_char1.size() == 4u);
113 static_assert(value_to_char1[0] == 'A');
114 static_assert(value_to_char1[1] == 'C');
115 static_assert(value_to_char1[2] == 'G');
116 static_assert(value_to_char1[3] == 'T');
117
118 constexpr array value_to_char2 = union_composition<dna4, gap>::make_value_to_char();
119 static_assert(value_to_char2.size() == 5u);
120 static_assert(value_to_char2[0] == 'A');
121 static_assert(value_to_char2[1] == 'C');
122 static_assert(value_to_char2[2] == 'G');
123 static_assert(value_to_char2[3] == 'T');
124 static_assert(value_to_char2[4] == '-');
125
126 constexpr array value_to_char3 = union_composition<dna4, gap, dna5>::make_value_to_char();
127 static_assert(value_to_char3.size() == 10u);
128 static_assert(value_to_char3[0] == 'A');
129 static_assert(value_to_char3[1] == 'C');
130 static_assert(value_to_char3[2] == 'G');
131 static_assert(value_to_char3[3] == 'T');
132 static_assert(value_to_char3[4] == '-');
133 static_assert(value_to_char3[5] == 'A');
134 static_assert(value_to_char3[6] == 'C');
135 static_assert(value_to_char3[7] == 'G');
136 static_assert(value_to_char3[8] == 'T');
137 static_assert(value_to_char3[9] == 'N');
138
139 constexpr array value_to_char4 = union_composition<dna5, gap, dna4>::make_value_to_char();
140 static_assert(value_to_char4.size() == 10u);
141 static_assert(value_to_char4[0] == 'A');
142 static_assert(value_to_char4[1] == 'C');
143 static_assert(value_to_char4[2] == 'G');
144 static_assert(value_to_char4[3] == 'T');
145 static_assert(value_to_char4[4] == 'N');
146 static_assert(value_to_char4[5] == '-');
147 static_assert(value_to_char4[6] == 'A');
148 static_assert(value_to_char4[7] == 'C');
149 static_assert(value_to_char4[8] == 'G');
150 static_assert(value_to_char4[9] == 'T');
151
152 constexpr array value_to_char5 = union_composition<gap, dna4, dna5>::make_value_to_char();
153 static_assert(value_to_char5.size() == 10u);
154 static_assert(value_to_char5[0] == '-');
155 static_assert(value_to_char5[1] == 'A');
156 static_assert(value_to_char5[2] == 'C');
157 static_assert(value_to_char5[3] == 'G');
158 static_assert(value_to_char5[4] == 'T');
159 static_assert(value_to_char5[5] == 'A');
160 static_assert(value_to_char5[6] == 'C');
161 static_assert(value_to_char5[7] == 'G');
162 static_assert(value_to_char5[8] == 'T');
163 static_assert(value_to_char5[9] == 'N');
164