AuroraRuntime/Source/Compression/AuCompression.hpp

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

    File: AuCompression.hpp
    Date: 2021-6-17
    Author: Reece
***/
#pragma once

namespace Aurora::Compression
{
    static const AuUInt64 kChunkSize = 32 * 1024;

    /// * compression type + bits -> internal zlib windowBits
    static bool CompressionLevelFromExternalApi(const DecompressInfo &info, AuInt8 &out)
    {
        out = 0;

        if (!info.bHasWindowbits)
        {
            if (info.alg == ECompressionType::eGZip)
            {
                out = 15 | 16;
            }
            else if (info.alg == ECompressionType::eDeflate)
            {
                out = -15;
            }
            else
            {
                out = 15;
                return true;
            }
        }

        if (info.uWindowBits < 0)
        {
            return {};
        }

        if (info.uWindowBits > 15)
        {
            return {};
        }

        if (info.alg == ECompressionType::eGZip)
        {
            out = info.uWindowBits | 16;
        }
        else if (info.alg == ECompressionType::eDeflate)
        {
            out = 0 - info.uWindowBits;
        }
        else
        {
            out = info.uWindowBits;
        }

        return true;
    }

    /// * compression type + bits -> internal zlib windowBits
    static bool CompressionLevelFromExternalApi(const CompressInfo &info, AuInt8 &out)
    {
        out = 0;

        if (!info.uWindowBits)
        {
            if (info.type == ECompressionType::eGZip)
            {
                out = 15 | 16;
            }
            else if (info.type == ECompressionType::eDeflate)
            {
                out = -15;
            }
            else
            {
                out = 15;
                return true;
            }
        }

        if (info.type == ECompressionType::eGZip)
        {
            out = info.uWindowBits | 16;
        }
        else if (info.type == ECompressionType::eDeflate)
        {
            out = 0 - info.uWindowBits;
        }
        else
        {
            out = info.uWindowBits;
        }

        return true;
    }

}