AuroraRuntime/Source/Compression/Compressors/BrotliDecompressor.hpp

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

    File: BrotliDecompressor.hpp
    Date: 2023-3-12
    Author: Reece
***/
#pragma once

#include "brotli/decode.h"

namespace Aurora::Compression
{
    struct BrotliInflate : BaseStream
    {
        DecompressInfo meta;

        BrotliInflate(const DecompressInfo &meta) : meta(meta), BaseStream(meta.uInternalStreamSize)
        { }

        ~BrotliInflate()
        {
            if (this->pState)
            {
                BrotliDecoderDestroyInstance(this->pState);
            }
        }

        bool Init(const AuSPtr<IO::IStreamReader> &reader) override
        {
            int ret;
            this->pReader_ = reader;

            if (!this->IsValid())
            {
                SysPushErrorMem();
                return false;
            }

            this->pState = BrotliDecoderCreateInstance(nullptr, nullptr, nullptr);
            if (!this->pState)
            {
                SysPushErrorMem("No brotli decoder");
                return false;
            }

            this->SetArray(this->din_);
            return true;
        }

        AuStreamReadWrittenPair_t Ingest_s(AuUInt32 input) override
        {
            AuUInt32 done {}, read {};

            if (!this->pReader_)
            {
                return {};
            }

            while (read < input)
            {
                read += IngestForInPointer<uint8_t, size_t>(this->pReader_, this->pInBuffer, this->uAvailIn, input - read);

                if (!this->uAvailIn)
                {
                    return { read, done };
                }

                size_t outNext {};
                uint8_t *pOut {};
                do
                {
                    outNext = AuArraySize(this->dout_);
                    pOut = this->dout_;
        
                    auto ret = BrotliDecoderDecompressStream(this->pState, &this->uAvailIn, (const uint8_t **)&this->pInBuffer, &outNext, &pOut, nullptr);
                    if (ret == BROTLI_DECODER_RESULT_ERROR)
                    {
                        SysPushErrorIO("Brotli Error");
                        this->pReader_.reset();
                        return AuMakePair(read, 0);
                    }

                    auto have = AuArraySize(this->dout_) - outNext;
                    done += have;

                    if (!Write(reinterpret_cast<const AuUInt8 *>(this->dout_), have))
                    {
                        this->pReader_.reset();
                        SysPushErrorIO("Compression Out of Overhead");
                        return AuMakePair(read, 0);
                    }
                }
                while (outNext == 0);
            }

            return { read, done };
        }

    private:
        AuSPtr<IO::IStreamReader> pReader_;
        unsigned char din_[kChunkSize];
        unsigned char dout_[kChunkSize];
        uint8_t *pInBuffer;
        size_t uAvailIn {};
        BrotliDecoderState *pState {};
    };
}