exercism-solutions/cpp/grains/grains.h

59 lines
1.2 KiB
C++

#pragma once
#define EXERCISM_RUN_ALL_TESTS
#include <limits>
#include <stdexcept>
template <size_t number_of_squares = 64,
typename ulong_t = unsigned long long>
class custom_grains
{
typedef typename std::numeric_limits<ulong_t> limits_t;
static_assert(std::is_unsigned<ulong_t>::value,
"ulong_t must be unsigned");
static_assert(number_of_squares <= limits_t::digits,
"ulong_t is too short");
struct total_as_max
{
static inline ulong_t total()
{
return limits_t::max();
}
};
struct total_by_shift
{
static inline ulong_t total()
{
return ulong_t(1) << number_of_squares - 1;
}
};
typedef typename std::conditional<
number_of_squares == limits_t::digits,
total_as_max,
total_by_shift>::type total_policy_t;
public:
static ulong_t square(size_t index)
{
if (index < 1 || index > number_of_squares)
throw std::domain_error("invalid square number");
return ulong_t(1) << (index - 1);
}
static ulong_t total()
{
return total_policy_t::total();
}
};
typedef custom_grains<> grains;