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

/***
    Copyright (C) 2022-2024 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: ViewSeekableWriter.hpp
    Date: 2024-03-05
    Author: Reece
***/
#pragma once

namespace Aurora::IO::Buffered
{
    struct ViewSeekableWriter : ISeekingWriter
    {
        AU_NO_COPY(ViewSeekableWriter)
        AU_MOVE(ViewSeekableWriter)
            
        inline ViewSeekableWriter(const AuSPtr<Memory::MemoryViewWrite> &pView) : view_(pView ? *pView.get() : Memory::MemoryViewWrite {}), pHold(pView)
        { }

        inline ViewSeekableWriter(const Memory::MemoryViewWrite &view, AuSPtr<void> pBlock) : view_(view), pHold(pBlock)
        { }

        inline ViewSeekableWriter()
        { }

        inline ~ViewSeekableWriter()
        { }

        inline virtual EStreamError IsOpen() override
        {
            if (!this->view_)
            {
                return EStreamError::eErrorStreamNotOpen;
            }

            if (!this->pHold)
            {
                return EStreamError::eErrorStreamNotOpen;
            }

            return EStreamError::eErrorNone;
        }

        inline virtual EStreamError ArbitraryWrite(AuUInt uOffset, const Memory::MemoryViewStreamRead &parameters) override
        {
            if (!this->view_)
            {
                return EStreamError::eErrorStreamNotOpen;
            }

            if (!this->pHold)
            {
                return EStreamError::eErrorStreamNotOpen;
            }

            auto iOffset = this->iBaseOffset + AuInt64(uOffset);
            if (iOffset < 0)
            {
                return EStreamError::eErrorOutOfBounds;
            }
            else
            {
                uOffset = iOffset;
            }

            if (this->view_.length < uOffset)
            {
                return EStreamError::eErrorEndOfStream;
            }

            auto uToRead = AuMin(this->view_.length - uOffset, parameters.length);
            parameters.outVariable = uToRead;
            AuMemcpy(this->view_.Begin<AuUInt8>() + uOffset, parameters.ptr, uToRead);
            return parameters.outVariable == 0 ? EStreamError::eErrorEndOfStream : EStreamError::eErrorNone;
        }

        inline virtual void Close() override
        {
            AuResetMember(this->pHold);
            AuResetMember(this->view_);
        }

        inline virtual void Flush() override
        {
        }

        inline AuInt64 &GetBaseOffset()
        {
            return this->iBaseOffset;
        }

        inline const AuInt64 &GetBaseOffset() const
        {
            return this->iBaseOffset;
        }

    private:
        Memory::MemoryViewWrite view_;
        AuSPtr<void> pHold;
        AuInt64 iBaseOffset {};
    };
}