AuroraRuntime/Include/Aurora/IO/Buffered/BlobReader.hpp

/***
    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(BlobReader)
        
        BlobReader(const AuSPtr<Memory::ByteBuffer> &buffer) : buffer_(buffer) {}
        BlobReader(Memory::ByteBuffer &&buffer) : buffer_(AuMakeShared<Memory::ByteBuffer>(buffer)) {}
        BlobReader(const Memory::ByteBuffer &buffer) : buffer_(AuMakeShared<Memory::ByteBuffer>(buffer)) {}

        BlobReader()  {}
        ~BlobReader() {}

        virtual EStreamError Open() override
        {
            if (!buffer_) return EStreamError::eErrorStreamNotOpen;
            if (!buffer_->operator bool()) return EStreamError::eErrorStreamNotOpen;
            return EStreamError::eErrorNone;
        }

        virtual EStreamError Read(const Memory::MemoryViewStreamWrite &paramters) override
        {
            auto realEndOffset = AuMin(buffer_->size() - offset_, paramters.length);
            if (realEndOffset == 0) return EStreamError::eErrorEndOfStream;

            paramters.outVariable = realEndOffset;
            AuMemcpy(paramters.ptr, buffer_->data() + offset_, realEndOffset);
            offset_ += realEndOffset;

            return EStreamError::eErrorNone;
        }

        virtual void Close() override
        {
            buffer_->clear();
        }

    private:
        AuSPtr<Memory::ByteBuffer> buffer_;
        AuUInt32 offset_ {};
    };
}