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

    File: BlobReader.hpp
    Date: 2021-6-10
    Author: Reece
***/
#pragma once

namespace Aurora::IO::Buffered
{
    class BlobReader : public IStreamReader
    {
    public:
        AU_NO_COPY_NO_MOVE(BlobReader)
        
        BlobReader(const AuList<AuUInt8> &buffer) : buffer_(buffer) {}
        BlobReader()  {}
        ~BlobReader() {}

        virtual EStreamError Open() override
        {
            return EStreamError::eErrorNone;
        }

        virtual EStreamError Read(void *buffer, AuUInt32 &len) override
        {
            auto oldLen = std::exchange(len, 0);

            auto realEndOffset = std::min(AuUInt32(buffer_.size())  - offset_, oldLen);
            if (realEndOffset == 0) return EStreamError::eErrorEndOfStream;

            len = realEndOffset;
            std::memcpy(buffer, buffer_.data() + offset_, len);
            offset_ += realEndOffset;

            return EStreamError::eErrorNone;
        }

        virtual void Close() override
        {
            buffer_.clear();
        }

    private:
        AuList<AuUInt8> buffer_;
        AuUInt32 offset_ {};
    };
}