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#pragma once
// random.hpp - Random number generation.
//
// Copyright © 2013 Ben Longbons <b.r.longbons@gmail.com>
//
// This file is part of The Mana World (Athena server)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "fwd.hpp"
#include "random.t.hpp"
#include <random>
namespace tmwa
{
// This is not namespace random since that collides with a C function,
// but this can be revisited when everything goes into namespace tmwa.
namespace random_
{
/// Get a random number from 0 .. 2**32 - 1
extern std::mt19937 generate;
/// Get a random number from 0 .. bound - 1
inline
int to(int bound)
{
std::uniform_int_distribution<int> dist(0, bound - 1);
return dist(generate);
}
/// Get a random number from low .. high (inclusive!)
inline
int in(int low, int high)
{
std::uniform_int_distribution<int> dist(low, high);
return dist(generate);
}
inline
bool coin()
{
// sigh, can't specify <bool> directly ...
std::uniform_int_distribution<int> dist(false, true);
return dist(generate);
}
inline
bool chance(Fraction f)
{
if (f.num <= 0)
return false;
if (f.num >= f.den)
return true;
return random_::to(f.den) < f.num;
}
// C is usually one of:
// std::vector<T>
// std::initializer_list<T>
// std::array<T, n>
template<class C>
auto choice(C&& c) -> decltype(*c.begin())
{
return *(c.begin() + random_::to(c.size()));
}
// allow bare braces
template<class T>
T choice(std::initializer_list<T>&& il)
{
return random_::choice(il);
}
} // namespace random_
} // namespace tmwa
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