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 AuUInt64 kFnv1MagicVal64   = 0xcbf29ce484222325;
        constexpr AuUInt64 kFnv1MagicPrime64 = 0x100000001b3;

        inline constexpr AuUInt64 fnv1a(const char *const str, const AuUInt64 value = kFnv1MagicVal64) noexcept
        {
            return (str[0] == '\0') ? value : fnv1a(&str[1], (value ^ AuUInt64(str[0])) * kFnv1MagicPrime64);
        }

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

        constexpr AuUInt32 kFnv1MagicVal32   = 0x811c9dc5;
        constexpr AuUInt32 kFnv1MagicPrime32 = 0x01000193;

        inline constexpr uint32_t fnv1a_32(const char *const str, const AuUInt32 value = kFnv1MagicVal32) noexcept
        {
            return (str[0] == '\0') ? value : fnv1a_32(&str[1], (value ^ AuUInt32(str[0])) * kFnv1MagicPrime32);
        }
    }
}