1 ///////////////////////////////////////////////////////////////
2 // Copyright 2012 John Maddock. Distributed under the Boost
3 // Software License, Version 1.0. (See accompanying file
4 // LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
5
6 //
7 // Compare arithmetic results using fixed_int to GMP results.
8 //
9
10 #ifdef _MSC_VER
11 #define _SCL_SECURE_NO_WARNINGS
12 #endif
13
14 #include <boost/multiprecision/cpp_int.hpp>
15 #include "test.hpp"
16 #include <boost/random/mersenne_twister.hpp>
17 #include <boost/random/uniform_int.hpp>
18
19 template <class T>
generate_random(unsigned bits_wanted)20 T generate_random(unsigned bits_wanted)
21 {
22 static boost::random::mt19937 gen;
23 typedef boost::random::mt19937::result_type random_type;
24
25 T max_val;
26 unsigned digits;
27 if (std::numeric_limits<T>::is_bounded && (bits_wanted == (unsigned)std::numeric_limits<T>::digits))
28 {
29 max_val = (std::numeric_limits<T>::max)();
30 digits = std::numeric_limits<T>::digits;
31 }
32 else
33 {
34 max_val = T(1) << bits_wanted;
35 digits = bits_wanted;
36 }
37
38 unsigned bits_per_r_val = std::numeric_limits<random_type>::digits - 1;
39 while ((random_type(1) << bits_per_r_val) > (gen.max)())
40 --bits_per_r_val;
41
42 unsigned terms_needed = digits / bits_per_r_val + 1;
43
44 T val = 0;
45 for (unsigned i = 0; i < terms_needed; ++i)
46 {
47 val *= (gen.max)();
48 val += gen();
49 }
50 val %= max_val;
51 return val;
52 }
53
54 template <class Number>
test_signed_overflow(Number a,Number b,const boost::mpl::true_ &)55 void test_signed_overflow(Number a, Number b, const boost::mpl::true_&)
56 {
57 a = -a;
58 BOOST_CHECK_THROW(Number(a * b), std::overflow_error);
59 ++a;
60 BOOST_CHECK(Number(a * b) >= (std::numeric_limits<Number>::min)());
61 }
62 template <class Number>
test_signed_overflow(Number,Number,const boost::mpl::false_ &)63 void test_signed_overflow(Number, Number, const boost::mpl::false_&)
64 {
65 }
66
67 template <class Number>
test()68 void test()
69 {
70 using namespace boost::multiprecision;
71 typedef Number test_type;
72
73 if (std::numeric_limits<test_type>::is_bounded)
74 {
75 test_type val = (std::numeric_limits<test_type>::max)();
76 #ifndef BOOST_NO_EXCEPTIONS
77 BOOST_CHECK_THROW(++val, std::overflow_error);
78 val = (std::numeric_limits<test_type>::max)();
79 BOOST_CHECK_THROW(test_type(1 + val), std::overflow_error);
80 BOOST_CHECK_THROW(test_type(val + 1), std::overflow_error);
81 BOOST_CHECK_THROW(test_type(2 * val), std::overflow_error);
82 val /= 2;
83 val += 1;
84 BOOST_CHECK_THROW(test_type(2 * val), std::overflow_error);
85
86 if (std::numeric_limits<test_type>::is_signed)
87 {
88 val = (std::numeric_limits<test_type>::min)();
89 BOOST_CHECK_THROW(--val, std::overflow_error);
90 val = (std::numeric_limits<test_type>::min)();
91 BOOST_CHECK_THROW(test_type(val - 1), std::overflow_error);
92 BOOST_CHECK_THROW(test_type(2 * val), std::overflow_error);
93 val /= 2;
94 val -= 1;
95 BOOST_CHECK_THROW(test_type(2 * val), std::overflow_error);
96 }
97 else
98 {
99 val = (std::numeric_limits<test_type>::min)();
100 BOOST_CHECK_THROW(--val, std::range_error);
101 val = (std::numeric_limits<test_type>::min)();
102 BOOST_CHECK_THROW(test_type(val - 1), std::range_error);
103 }
104 #endif
105 //
106 // Test overflow in random values:
107 //
108 for (unsigned bits = 30; bits < std::numeric_limits<test_type>::digits; bits += 30)
109 {
110 for (unsigned i = 0; i < 100; ++i)
111 {
112 val = static_cast<test_type>(generate_random<cpp_int>(bits));
113 test_type val2 = 1 + (std::numeric_limits<test_type>::max)() / val;
114 BOOST_CHECK_THROW(test_type(val2 * val), std::overflow_error);
115 test_signed_overflow(val2, val, boost::mpl::bool_<std::numeric_limits<test_type>::is_signed>());
116 --val2;
117 BOOST_CHECK(cpp_int(val2) * cpp_int(val) <= cpp_int((std::numeric_limits<test_type>::max)()));
118 BOOST_CHECK(val2 * val <= (std::numeric_limits<test_type>::max)());
119 val2 = (std::numeric_limits<test_type>::max)() - val;
120 ++val2;
121 BOOST_CHECK_THROW(test_type(val2 + val), std::overflow_error);
122 BOOST_CHECK((val2 - 1) + val == (std::numeric_limits<test_type>::max)());
123 if (std::numeric_limits<test_type>::is_signed)
124 {
125 val2 = (std::numeric_limits<test_type>::min)() + val;
126 --val2;
127 BOOST_CHECK_THROW(test_type(val2 - val), std::overflow_error);
128 ++val2;
129 BOOST_CHECK(val2 - val == (std::numeric_limits<test_type>::min)());
130 }
131 unsigned shift = std::numeric_limits<test_type>::digits - msb(val);
132 BOOST_CHECK_THROW((val << shift) > 0, std::overflow_error);
133 }
134 }
135 }
136
137 #ifndef BOOST_NO_EXCEPTIONS
138 if (std::numeric_limits<test_type>::is_signed)
139 {
140 test_type a = -1;
141 test_type b = 1;
142 BOOST_CHECK_THROW(test_type(a | b), std::range_error);
143 BOOST_CHECK_THROW(test_type(a & b), std::range_error);
144 BOOST_CHECK_THROW(test_type(a ^ b), std::range_error);
145 }
146 else
147 {
148 // Constructing from a negative value is not allowed:
149 BOOST_CHECK_THROW(test_type(-2), std::range_error);
150 BOOST_CHECK_THROW(test_type("-2"), std::range_error);
151 }
152 if (std::numeric_limits<test_type>::digits < std::numeric_limits<long long>::digits)
153 {
154 long long llm = (std::numeric_limits<long long>::max)();
155 test_type t;
156 BOOST_CHECK_THROW(t = llm, std::range_error);
157 BOOST_CHECK_THROW(t = static_cast<test_type>(llm), std::range_error);
158 unsigned long long ullm = (std::numeric_limits<unsigned long long>::max)();
159 BOOST_CHECK_THROW(t = ullm, std::range_error);
160 BOOST_CHECK_THROW(t = static_cast<test_type>(ullm), std::range_error);
161
162 static const checked_uint512_t big = (std::numeric_limits<checked_uint512_t>::max)();
163 BOOST_CHECK_THROW(t = static_cast<test_type>(big), std::range_error);
164 }
165 //
166 // String errors:
167 //
168 BOOST_CHECK_THROW(test_type("12A"), std::runtime_error);
169 BOOST_CHECK_THROW(test_type("0658"), std::runtime_error);
170
171 if (std::numeric_limits<test_type>::is_signed)
172 {
173 BOOST_CHECK_THROW(test_type(-2).str(0, std::ios_base::hex), std::runtime_error);
174 BOOST_CHECK_THROW(test_type(-2).str(0, std::ios_base::oct), std::runtime_error);
175 }
176 #endif
177 }
178
main()179 int main()
180 {
181 using namespace boost::multiprecision;
182
183 test<number<cpp_int_backend<0, 0, signed_magnitude, checked> > >();
184 test<checked_int512_t>();
185 test<checked_uint512_t>();
186 test<number<cpp_int_backend<32, 32, signed_magnitude, checked, void> > >();
187 test<number<cpp_int_backend<32, 32, unsigned_magnitude, checked, void> > >();
188
189 //
190 // We also need to test type with "odd" bit counts in order to ensure full code coverage:
191 //
192 test<number<cpp_int_backend<528, 528, signed_magnitude, checked, void> > >();
193 test<number<cpp_int_backend<528, 528, unsigned_magnitude, checked, void> > >();
194 test<number<cpp_int_backend<48, 48, signed_magnitude, checked, void> > >();
195 test<number<cpp_int_backend<48, 48, unsigned_magnitude, checked, void> > >();
196 return boost::report_errors();
197 }
198