AuroraRuntime/Include/Aurora/Hashing/CE/fnv1.hpp

/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: fnv1.hpp
    Date: 2021-6-10
    Author: Reece
***/
#pragma once

namespace Aurora::Hashing
{
    namespace CE
    {
        constexpr uint64_t kFnv1MagicVal64   = 0xcbf29ce484222325;
        constexpr uint64_t kFnv1MagicPrime64 = 0x100000001b3;

        inline constexpr uint64_t fnv1a(const char *const str, const uint64_t value = kFnv1MagicVal64) noexcept
        {
            return (str[0] == '\0') ? value : fnv1a(&str[1], (value ^ uint64_t(str[0])) * kFnv1MagicPrime64);
        }

        inline constexpr uint32_t fnv1a_trunc(const char *const str) noexcept
        {
            return static_cast<uint32_t>(fnv1a(str));
        }

        constexpr uint64_t kFnv1MagicVal32   = 0x811c9dc5;
        constexpr uint64_t kFnv1MagicPrime32 = 0x01000193;

        inline constexpr uint32_t fnv1a_32(const char *const str, const uint32_t value = kFnv1MagicVal32) noexcept
        {
            return (str[0] == '\0') ? value : fnv1a_32(&str[1], (value ^ uint32_t(str[0])) * kFnv1MagicPrime32);
        }
    }
}