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

    File: Compression.cpp
    Date: 2021-6-17
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "Compression.hpp"

#include "zstd.h"

namespace Aurora::Compression
{
    AUKN_SYM bool Compress(const Memory::MemoryViewRead &source, Memory::ByteBuffer &out, int compressionLevel)
    {
        if (!AuTryResize(out, source.length))
        {
            return false;
        }

        auto ret = ZSTD_compress(out.data(), out.size(), source.ptr, source.length, compressionLevel);
        if (ZSTD_isError(ret))
        {
            return false;
        }

        out.resize(ret);
        return true;
    }
    
    AUKN_SYM bool Decompress(const Memory::MemoryViewRead &source, AuByteBuffer &out)
    {
        AuUInt32 read = 0;

        while (read != source.length)
        {
            auto startPtr = reinterpret_cast<const AuUInt8 *>(source.ptr) + read;
            auto deflatedLength = ZSTD_findFrameCompressedSize(startPtr, source.length - read);
            auto inflatedLength = ZSTD_getFrameContentSize(startPtr, source.length - read);

            if (inflatedLength == ZSTD_CONTENTSIZE_ERROR)
            {
                return false;
            }

            if (inflatedLength == ZSTD_CONTENTSIZE_UNKNOWN)
            {
                return false;
            }

            if (ZSTD_isError(inflatedLength))
            {
                return false;
            }
            
            auto startingSize = out.size();

            if (!AuTryResize(out, startingSize + inflatedLength))
            {
                return false;
            }

            auto ret = ZSTD_decompress(&out[startingSize], inflatedLength, source.ptr, source.length);
            if (ZSTD_isError(ret))
            {
                return false;
            }

            out.resize(startingSize + ret);

            read += deflatedLength;
        }

        return true;
    }
}