rng.cpp

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/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2025 Yaroslav Riabtsev <yaroslav.riabtsev@rwth-aachen.de>
 *
 * 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 NON-INFRINGEMENT. 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.
 */
 
#include "rng.hpp"
 
namespace corespace {
std::mt19937_64& rng() {
    static std::mt19937_64 gen { std::random_device {}() };
    return gen;
}
 
std::string random_hex(const std::size_t n) {
    static constexpr char digits[] = "0123456789abcdef";
    static thread_local std::uniform_int_distribution<int> nibble(0, 15);
 
    std::string out;
    out.resize(n);
    auto& g = rng();
    for (std::size_t i = 0; i < n; ++i) {
        out[i] = digits[nibble(g)];
    }
    return out;
}
}