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///////////////////////////////////////////////////////////////
// Copyright 2017 John Maddock. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
//
// Check results of truncated overflow.
//
#ifdef _MSC_VER
#define _SCL_SECURE_NO_WARNINGS
#endif
#include <boost/multiprecision/cpp_int.hpp>
#include "test.hpp"
#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int.hpp>
template <class T>
T generate_random(unsigned bits_wanted)
{
static boost::random::mt19937 gen;
typedef boost::random::mt19937::result_type random_type;
T max_val;
unsigned digits;
if (std::numeric_limits<T>::is_bounded && (bits_wanted == (unsigned)std::numeric_limits<T>::digits))
{
max_val = (std::numeric_limits<T>::max)();
digits = std::numeric_limits<T>::digits;
}
else
{
max_val = T(1) << bits_wanted;
digits = bits_wanted;
}
unsigned bits_per_r_val = std::numeric_limits<random_type>::digits - 1;
while ((random_type(1) << bits_per_r_val) > (gen.max)())
--bits_per_r_val;
unsigned terms_needed = digits / bits_per_r_val + 1;
T val = 0;
for (unsigned i = 0; i < terms_needed; ++i)
{
val *= (gen.max)();
val += gen();
}
val %= max_val;
return val;
}
template <class Number>
void test()
{
using namespace boost::multiprecision;
typedef Number test_type;
for (unsigned i = 30; i < std::numeric_limits<test_type>::digits; ++i)
{
for (unsigned j = std::numeric_limits<test_type>::digits - i - 1; j < std::numeric_limits<test_type>::digits; ++j)
{
for (unsigned k = 0; k < 10; ++k)
{
test_type a = static_cast<test_type>(generate_random<cpp_int>(i));
test_type b = static_cast<test_type>(generate_random<cpp_int>(j));
test_type c = static_cast<test_type>(cpp_int(a) * cpp_int(b));
test_type d = a * b;
BOOST_CHECK_EQUAL(c, d);
if ((k == 0) && (j == 0))
{
for (unsigned s = 1; s < std::numeric_limits<test_type>::digits; ++s)
BOOST_CHECK_EQUAL(a << s, test_type(cpp_int(a) << s));
}
}
}
}
}
int main()
{
using namespace boost::multiprecision;
test<int512_t>();
test<uint512_t>();
//
// We also need to test type with "odd" bit counts in order to ensure full code coverage:
//
test<number<cpp_int_backend<528, 528, signed_magnitude, unchecked, void> > >();
test<number<cpp_int_backend<528, 528, unsigned_magnitude, unchecked, void> > >();
test<number<cpp_int_backend<48, 48, signed_magnitude, unchecked, void> > >();
test<number<cpp_int_backend<48, 48, unsigned_magnitude, unchecked, void> > >();
return boost::report_errors();
}
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