multiprecision/test/test_checked_cpp_int.cpp

198 lines
7.0 KiB
C++

///////////////////////////////////////////////////////////////
// Copyright 2012 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
//
// Compare arithmetic results using fixed_int to GMP results.
//
#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_signed_overflow(Number a, Number b, const boost::mpl::true_&)
{
a = -a;
BOOST_CHECK_THROW(Number(a * b), std::overflow_error);
++a;
BOOST_CHECK(Number(a * b) >= (std::numeric_limits<Number>::min)());
}
template <class Number>
void test_signed_overflow(Number a, Number b, const boost::mpl::false_&)
{
}
template <class Number>
void test()
{
using namespace boost::multiprecision;
typedef Number test_type;
if (std::numeric_limits<test_type>::is_bounded)
{
test_type val = (std::numeric_limits<test_type>::max)();
#ifndef BOOST_NO_EXCEPTIONS
BOOST_CHECK_THROW(++val, std::overflow_error);
val = (std::numeric_limits<test_type>::max)();
BOOST_CHECK_THROW(test_type(1 + val), std::overflow_error);
BOOST_CHECK_THROW(test_type(val + 1), std::overflow_error);
BOOST_CHECK_THROW(test_type(2 * val), std::overflow_error);
val /= 2;
val += 1;
BOOST_CHECK_THROW(test_type(2 * val), std::overflow_error);
if (std::numeric_limits<test_type>::is_signed)
{
val = (std::numeric_limits<test_type>::min)();
BOOST_CHECK_THROW(--val, std::overflow_error);
val = (std::numeric_limits<test_type>::min)();
BOOST_CHECK_THROW(test_type(val - 1), std::overflow_error);
BOOST_CHECK_THROW(test_type(2 * val), std::overflow_error);
val /= 2;
val -= 1;
BOOST_CHECK_THROW(test_type(2 * val), std::overflow_error);
}
else
{
val = (std::numeric_limits<test_type>::min)();
BOOST_CHECK_THROW(--val, std::range_error);
val = (std::numeric_limits<test_type>::min)();
BOOST_CHECK_THROW(test_type(val - 1), std::range_error);
}
#endif
//
// Test overflow in random values:
//
for (unsigned bits = 30; bits < std::numeric_limits<test_type>::digits; bits += 30)
{
for (unsigned i = 0; i < 100; ++i)
{
val = static_cast<test_type>(generate_random<cpp_int>(bits));
test_type val2 = 1 + (std::numeric_limits<test_type>::max)() / val;
BOOST_CHECK_THROW(test_type(val2 * val), std::overflow_error);
test_signed_overflow(val2, val, boost::mpl::bool_<std::numeric_limits<test_type>::is_signed>());
--val2;
BOOST_CHECK(cpp_int(val2) * cpp_int(val) <= cpp_int((std::numeric_limits<test_type>::max)()));
BOOST_CHECK(val2 * val <= (std::numeric_limits<test_type>::max)());
val2 = (std::numeric_limits<test_type>::max)() - val;
++val2;
BOOST_CHECK_THROW(test_type(val2 + val), std::overflow_error);
BOOST_CHECK((val2 - 1) + val == (std::numeric_limits<test_type>::max)());
if (std::numeric_limits<test_type>::is_signed)
{
val2 = (std::numeric_limits<test_type>::min)() + val;
--val2;
BOOST_CHECK_THROW(test_type(val2 - val), std::overflow_error);
++val2;
BOOST_CHECK(val2 - val == (std::numeric_limits<test_type>::min)());
}
unsigned shift = std::numeric_limits<test_type>::digits - msb(val);
BOOST_CHECK_THROW((val << shift) > 0, std::overflow_error);
}
}
}
#ifndef BOOST_NO_EXCEPTIONS
if (std::numeric_limits<test_type>::is_signed)
{
test_type a = -1;
test_type b = 1;
BOOST_CHECK_THROW(test_type(a | b), std::range_error);
BOOST_CHECK_THROW(test_type(a & b), std::range_error);
BOOST_CHECK_THROW(test_type(a ^ b), std::range_error);
}
else
{
// Constructing from a negative value is not allowed:
BOOST_CHECK_THROW(test_type(-2), std::range_error);
BOOST_CHECK_THROW(test_type("-2"), std::range_error);
}
if (std::numeric_limits<test_type>::digits < std::numeric_limits<long long>::digits)
{
long long llm = (std::numeric_limits<long long>::max)();
test_type t;
BOOST_CHECK_THROW(t = llm, std::range_error);
BOOST_CHECK_THROW(t = static_cast<test_type>(llm), std::range_error);
unsigned long long ullm = (std::numeric_limits<unsigned long long>::max)();
BOOST_CHECK_THROW(t = ullm, std::range_error);
BOOST_CHECK_THROW(t = static_cast<test_type>(ullm), std::range_error);
static const checked_uint512_t big = (std::numeric_limits<checked_uint512_t>::max)();
BOOST_CHECK_THROW(t = static_cast<test_type>(big), std::range_error);
}
//
// String errors:
//
BOOST_CHECK_THROW(test_type("12A"), std::runtime_error);
BOOST_CHECK_THROW(test_type("0658"), std::runtime_error);
if (std::numeric_limits<test_type>::is_signed)
{
BOOST_CHECK_THROW(test_type(-2).str(0, std::ios_base::hex), std::runtime_error);
BOOST_CHECK_THROW(test_type(-2).str(0, std::ios_base::oct), std::runtime_error);
}
#endif
}
int main()
{
using namespace boost::multiprecision;
test<number<cpp_int_backend<0, 0, signed_magnitude, checked> > >();
test<checked_int512_t>();
test<checked_uint512_t>();
test<number<cpp_int_backend<32, 32, signed_magnitude, checked, void> > >();
test<number<cpp_int_backend<32, 32, unsigned_magnitude, checked, void> > >();
//
// 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, checked, void> > >();
test<number<cpp_int_backend<528, 528, unsigned_magnitude, checked, void> > >();
test<number<cpp_int_backend<48, 48, signed_magnitude, checked, void> > >();
test<number<cpp_int_backend<48, 48, unsigned_magnitude, checked, void> > >();
return boost::report_errors();
}