/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: auMagicUtils.hpp
    Date: 2022-2-1
    Author: Reece
***/
#pragma once

static constexpr auline AuUInt32 AuConvertMagicTag32(const char buffer[4])
{
    AuUInt32 magic {};
    if (Aurora::Build::kCurrentEndian == Aurora::Build::ECPUEndian::eCPULittle)
    {
        magic |= AuUInt32(buffer[0]);
        magic |= AuUInt32(buffer[1]) << 8;
        magic |= AuUInt32(buffer[2]) << 16;
        magic |= AuUInt32(buffer[3]) << 24;
        // LE will look alright in memory dumps
        // MSFT uses tags that read back the initial string value when read back hex ints
        // I prefer binary streams and file headers contain a 4x or 8x ascii char headers (eg. LuaX)
    }
    else
    {
        // Lazy reinterpret cast reads will always be flipped
        // Assume byte buffers read/write machine endian 
        // Assume *reinterpret_cast<T*> returns machine endian
        // BE needs to be flipped in memory 
        // BE will look fine in memory dumps
        // BE will also look fine in stack/variable dumps when printed in hex
        magic |= AuUInt32(buffer[4]);
        magic |= AuUInt32(buffer[2]) << 8;
        magic |= AuUInt32(buffer[1]) << 16;
        magic |= AuUInt32(buffer[0]) << 24;
    }
    // Determinstic across platforms, perhaps unexpected by endian normalized streams
    // When asserting read(noEndian) against a tag, an endian swap would cause the
    // assertion to fail, thus providing you with the endian match check
    // This step is delegated to a de-facto machine endian buffer builder
    // ByteBuffers that normalize for endianness continue to work with tags
    // irrespective of reader/writer endianness 
    return magic;
}

static constexpr auline AuUInt64 AuConvertMagicTag64(const char buffer[8])
{
    AuUInt64 magic {};
    if (Aurora::Build::kCurrentEndian == Aurora::Build::ECPUEndian::eCPULittle)
    {
        magic |= AuUInt64(buffer[0]);
        magic |= AuUInt64(buffer[1]) << 8;
        magic |= AuUInt64(buffer[2]) << 16;
        magic |= AuUInt64(buffer[3]) << 24;
        magic |= AuUInt64(buffer[4]) << 32;
        magic |= AuUInt64(buffer[5]) << 40;
        magic |= AuUInt64(buffer[6]) << 48;
        magic |= AuUInt64(buffer[7]) << 56;
    }
    else
    {
        magic |= AuUInt64(buffer[7]);
        magic |= AuUInt64(buffer[6]) << 8;
        magic |= AuUInt64(buffer[5]) << 16;
        magic |= AuUInt64(buffer[4]) << 24;
        magic |= AuUInt64(buffer[3]) << 32;
        magic |= AuUInt64(buffer[2]) << 40;
        magic |= AuUInt64(buffer[1]) << 48;
        magic |= AuUInt64(buffer[0]) << 56;
    }
    return magic;
}