1 // Copyright (C) 2015-2021 Free Software Foundation, Inc.
2 //
3 // This file is part of the GNU ISO C++ Library. This library is free
4 // software; you can redistribute it and/or modify it under the
5 // terms of the GNU General Public License as published by the
6 // Free Software Foundation; either version 3, or (at your option)
7 // any later version.
8
9 // This library is distributed in the hope that it will be useful,
10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 // GNU General Public License for more details.
13
14 // You should have received a copy of the GNU General Public License along
15 // with this library; see the file COPYING3. If not see
16 // <http://www.gnu.org/licenses/>.
17
18 // { dg-do compile { target c++14 } }
19
20 #include <experimental/numeric>
21 #include <experimental/type_traits>
22
23 #ifndef __cpp_lib_experimental_gcd_lcm
24 # error "Feature-test macro for gcd missing"
25 #elif __cpp_lib_experimental_gcd_lcm != 201411
26 # error "Feature-test macro for gcd has wrong value"
27 #endif
28
29 using std::experimental::fundamentals_v2::gcd;
30 using std::experimental::is_same_v;
31
32 static_assert( gcd(1071, 462) == 21, "" );
33 static_assert( gcd(2000, 20) == 20, "" );
34 static_assert( gcd(2011, 17) == 1, "GCD of two primes is 1" );
35 static_assert( gcd(200, 200) == 200, "GCD of equal numbers is that number" );
36 static_assert( gcd(0, 13) == 13, "GCD of any number and 0 is that number" );
37 static_assert( gcd(29, 0) == 29, "GCD of any number and 0 is that number" );
38 static_assert( gcd(0, 0) == 0, "Zarro Boogs found" );
39
40 static_assert(gcd(1u, 2) == 1, "unsigned and signed");
41 static_assert(gcd(9, 6u) == 3, "unsigned and signed");
42 static_assert(gcd(3, 4u) == 1, "signed and unsigned");
43 static_assert(gcd(32u, 24) == 8, "signed and unsigned");
44 static_assert(gcd(1u, -2) == 1, "unsigned and negative");
45 static_assert(gcd(-21, 28u) == 7, "unsigned and negative");
46 static_assert(gcd(-3, 4u) == 1, "negative and unsigned");
47 static_assert(gcd(33u, -44) == 11, "negative and unsigned");
48 static_assert(gcd(5u, 6u) == 1, "unsigned and unsigned");
49 static_assert(gcd(54u, 36u) == 18, "unsigned and unsigned");
50 static_assert(gcd(-5, -6) == 1, "negative and negative");
51 static_assert(gcd(-50, -60) == 10, "negative and negative");
52
53 static_assert( is_same_v<decltype(gcd(1l, 1)), long>, "" );
54 static_assert( is_same_v<decltype(gcd(1ul, 1ull)), unsigned long long>, "" );
55
56 #include <climits>
57 #include <testsuite_hooks.h>
58
59 constexpr struct testcase { unsigned long long p, q, r; } testcases[] = {
60 { 5, 8, 1 },
61 { 6, 35, 1 },
62 { 30, 42, 6 },
63 { 24, 60, 12 },
64 { 55, 144, 1 },
65 { 105, 252, 21 },
66 { 253, 22121, 11 },
67 { 1386, 3213, 63 },
68 { 2028, 2049, 3 },
69 { 46391, 62527, 2017 },
70 { 63245986, 39088169, 1 },
71 { 77160074263, 47687519812, 1 },
72 { 77160074264, 47687519812, 4 },
73 };
74
75 template<typename P, typename Q>
76 constexpr bool
check(P p,Q q,unsigned long long r)77 check(P p, Q q, unsigned long long r)
78 {
79 using R = std::common_type_t<P, Q>;
80 static_assert( is_same_v<decltype(gcd(p, q)), R>, "" );
81 static_assert( is_same_v<decltype(gcd(q, p)), R>, "" );
82 R r1 = gcd(p, q);
83 // Check non-negative, so conversion to unsigned long doesn't alter value.
84 VERIFY( r1 >= 0 );
85 // Check for expected result
86 VERIFY( (unsigned long long)r1 == r );
87 // Check reversing arguments doesn't change result
88 VERIFY( gcd(q, p) == r1 );
89
90 P pabs = p < 0 ? -p : p;
91 VERIFY( gcd(p, p) == pabs );
92 VERIFY( gcd(0, p) == pabs );
93 VERIFY( gcd(p, 0) == pabs );
94 VERIFY( gcd(1, p) == 1 );
95 VERIFY( gcd(p, 1) == 1 );
96 Q qabs = q < 0 ? -q : q;
97 VERIFY( gcd(q, q) == qabs );
98 VERIFY( gcd(0, q) == qabs );
99 VERIFY( gcd(q, 0) == qabs );
100 VERIFY( gcd(1, q) == 1 );
101 VERIFY( gcd(q, 1) == 1 );
102 VERIFY( gcd(r, r) == r );
103 VERIFY( gcd(0, r) == r );
104 VERIFY( gcd(r, 0) == r );
105 VERIFY( gcd(1, r) == 1 );
106 VERIFY( gcd(r, 1) == 1 );
107
108 return true;
109 }
110
111 constexpr bool
test01()112 test01()
113 {
114 for (auto t : testcases)
115 {
116 check(t.p, t.q, t.r);
117
118 if (t.p <= LONG_MAX && t.q <= LONG_MAX)
119 {
120 check( (long)t.p, (long)t.p, t.p);
121 check(-(long)t.p, (long)t.p, t.p);
122 check(-(long)t.p, -(long)t.p, t.p);
123
124 check( (long)t.p, t.q, t.r);
125 check(-(long)t.p, t.q, t.r);
126
127 check(t.p, (long)t.q, t.r);
128 check(t.p, -(long)t.q, t.r);
129
130 check( (long)t.p, (long)t.q, t.r);
131 check( (long)t.p, -(long)t.q, t.r);
132 check(-(long)t.p, (long)t.q, t.r);
133 check(-(long)t.p, -(long)t.q, t.r);
134 }
135
136 if (t.p <= INT_MAX && t.q <= INT_MAX)
137 {
138 check((long)t.p, (int)t.q, t.r);
139 check(-(int)t.p, (long)t.q, t.r);
140
141 check( (int)t.p, (unsigned)t.q, t.r);
142 check(-(int)t.p, (unsigned)t.q, t.r);
143
144 check(-(int)t.p, -(int)t.q, t.r);
145 check(-(int)t.p, -(long)t.q, t.r);
146 }
147
148 if (t.p <= SHRT_MAX && t.q <= SHRT_MAX)
149 {
150 check( (long)t.p, (short)t.q, t.r);
151 check(-(short)t.p, (long)t.q, t.r);
152
153 check( (short)t.p, (unsigned short)t.q, t.r);
154 check(-(short)t.p, (unsigned short)t.q, t.r);
155
156 check(-(short)t.p, -(short)t.q, t.r);
157 check(-(short)t.p, -(long)t.q, t.r);
158 }
159 }
160 return true;
161 }
162
163
main()164 int main()
165 {
166 static_assert( test01() ); // constexpr
167 VERIFY( test01() ); // non-constexpr
168 }
169