Sprout/sprout/uuid/random_generator.hpp
2013-08-07 00:15:09 +09:00

112 lines
3.7 KiB
C++

#ifndef SPROUT_UUID_RANDOM_GENERATOR_HPP
#define SPROUT_UUID_RANDOM_GENERATOR_HPP
#include <cstdint>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/limits.hpp>
#include <sprout/uuid/uuid.hpp>
#include <sprout/random/default_random_engine.hpp>
#include <sprout/random/uniform_int_distribution.hpp>
#include <sprout/random/variate_generator.hpp>
namespace sprout {
namespace uuids {
//
// basic_random_generator
//
template<typename UniformRandomNumberGenerator = sprout::random::default_random_engine>
class basic_random_generator {
public:
typedef sprout::uuids::uuid result_type;
private:
typedef UniformRandomNumberGenerator engine_type;
typedef sprout::random::uniform_int_distribution<std::uint32_t> distribution_type;
typedef typename result_type::value_type value_type;
private:
distribution_type distribution_;
private:
SPROUT_CONSTEXPR result_type random_to_uuid_1(std::uint32_t v0, std::uint32_t v1, std::uint32_t v2, std::uint32_t v3) const {
return result_type{{
static_cast<value_type>((v0 >> 24) & 0xFF),
static_cast<value_type>((v0 >> 16) & 0xFF),
static_cast<value_type>((v0 >> 8) & 0xFF),
static_cast<value_type>((v0) & 0xFF),
static_cast<value_type>((v1 >> 24) & 0xFF),
static_cast<value_type>((v1 >> 16) & 0xFF),
static_cast<value_type>(((v1 >> 8) & 0x4F) | 0x40),
static_cast<value_type>((v1) & 0xFF),
static_cast<value_type>(((v2 >> 24) & 0xBF) | 0x80),
static_cast<value_type>((v2 >> 16) & 0xFF),
static_cast<value_type>((v2 >> 8) & 0xFF),
static_cast<value_type>((v2) & 0xFF),
static_cast<value_type>((v3 >> 24) & 0xFF),
static_cast<value_type>((v3 >> 16) & 0xFF),
static_cast<value_type>((v3 >> 8) & 0xFF),
static_cast<value_type>((v3) & 0xFF)
}};
}
template<typename Random, typename... Args>
SPROUT_CONSTEXPR typename std::enable_if<
sizeof...(Args) == 3,
result_type
>::type random_to_uuid(Random const& rnd, Args... args) const {
return random_to_uuid_1(args..., rnd.result());
}
template<typename Random, typename... Args>
SPROUT_CONSTEXPR typename std::enable_if<
sizeof...(Args) != 3,
result_type
>::type random_to_uuid(Random const& rnd, Args... args) const {
return random_to_uuid(rnd(), args..., rnd.result());
}
public:
SPROUT_CONSTEXPR basic_random_generator()
: distribution_(sprout::numeric_limits<std::uint32_t>::min(), sprout::numeric_limits<std::uint32_t>::max())
{}
template<typename T>
SPROUT_CONSTEXPR typename std::enable_if<
std::is_integral<T>::value,
result_type
>::type
operator()(T const& seed) const {
return operator()(engine_type(seed));
}
template<typename Engine>
SPROUT_CONSTEXPR typename std::enable_if<
!std::is_integral<Engine>::value,
result_type
>::type
operator()(Engine const& engine) const {
return random_to_uuid(sprout::random::combine(engine, distribution_)());
}
};
//
// random_generator
//
typedef sprout::uuids::basic_random_generator<> random_generator;
//
// make_uuid4
//
template<typename T>
SPROUT_CONSTEXPR typename std::enable_if<
std::is_integral<T>::value,
sprout::uuids::uuid
>::type
make_uuid4(T const& seed) {
return sprout::uuids::random_generator()(seed);
}
template<typename Engine>
SPROUT_CONSTEXPR typename std::enable_if<
!std::is_integral<Engine>::value,
sprout::uuids::uuid
>::type
make_uuid4(Engine const& engine) {
return sprout::uuids::random_generator()(engine);
}
} // namespace uuids
} // namespace sprout
#endif // #ifndef SPROUT_UUID_RANDOM_GENERATOR_HPP