#include "int-hash.hpp"
#include <bit>

namespace floormat {

size_t int_hash(uint32_t x) noexcept
{
    if constexpr(sizeof(size_t) == 4)
    {
        // by Chris Wellons <https://nullprogram.com/blog/2018/07/31/>

        x ^= x >> 15;
        x *= 0x2c1b3c6dU;
        x ^= x >> 12;
        x *= 0x297a2d39U;
        x ^= x >> 15;

        return x;
    }
    else
        return int_hash(uint64_t(x));
}

size_t int_hash(uint64_t x) noexcept
{
    // NASAM by Pelle Evensen <https://mostlymangling.blogspot.com/2020/01/nasam-not-another-strange-acronym-mixer.html>

    x ^= std::rotr(x, 25) ^ std::rotr(x, 47);
    x *= 0x9E6C63D0676A9A99UL;
    x ^= x >> 23 ^ x >> 51;
    x *= 0x9E6D62D06F6A9A9BUL;
    x ^= x >> 23 ^ x >> 51;

    return x;
}

} // namespace floormat