Random.h

// Copyright (c) 2016-2018 Kiwano - Nomango
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
 
#pragma once
#include <random>
 
namespace kiwano
{
namespace math
{
//
// 随机数
//
// 获取指定范围内的一个随机数, 如:
// int n = math::Random(1, 5);  // 获取 1~5 内的随机整数, 包含 1 和 5
// 产生的随机数类型取决于参数的类型, 如获取随机浮点数:
// float d = math::Random(1.2f, 1.5f);
//
 
int Random(int min, int max);
 
unsigned int Random(unsigned int min, unsigned int max);
 
long Random(long min, long max);
 
unsigned long Random(unsigned long min, unsigned long max);
 
char Random(char min, char max);
 
float Random(float min, float max);
 
double Random(double min, double max);
 
//
// Details of math::Rand
//
 
namespace __rand_detail
{
inline std::default_random_engine& GetRandomEngine()
{
    static std::random_device         device;
    static std::default_random_engine engine(device());
    return engine;
}
 
template <typename T>
inline T RandomInt(T min, T max)
{
    std::uniform_int_distribution<T> dist(min, max);
    return dist(GetRandomEngine());
}
 
template <typename T>
inline T RandomReal(T min, T max)
{
    std::uniform_real_distribution<T> dist(min, max);
    return dist(GetRandomEngine());
}
}  // namespace __rand_detail
 
inline int Random(int min, int max)
{
    return __rand_detail::RandomInt(min, max);
}
 
inline unsigned int Random(unsigned int min, unsigned int max)
{
    return __rand_detail::RandomInt(min, max);
}
 
inline long Random(long min, long max)
{
    return __rand_detail::RandomInt(min, max);
}
 
inline unsigned long Random(unsigned long min, unsigned long max)
{
    return __rand_detail::RandomInt(min, max);
}
 
inline char Random(char min, char max)
{
    return static_cast<char>(__rand_detail::RandomInt(static_cast<int>(min), static_cast<int>(max)));
}
 
inline float Random(float min, float max)
{
    return __rand_detail::RandomReal(min, max);
}
 
inline double Random(double min, double max)
{
    return __rand_detail::RandomReal(min, max);
}
}  // namespace math
}  // namespace kiwano