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

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

    File: ViewSeekableReadable.hpp
    Date: 2022-12-11
    Author: Reece
***/
#pragma once

namespace Aurora::IO::Buffered
{
    struct ViewSeekableReadable : ISeekingReader
    {
        AU_NO_COPY(ViewSeekableReadable)

        inline ViewSeekableReadable(const AuSPtr<Memory::MemoryViewRead> &view) : view_(view)
        { }

        inline ViewSeekableReadable()
        { }

        inline ~ViewSeekableReadable()
        { }

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

            if (!(*this->view_.get()))
            {
                return EStreamError::eErrorStreamNotOpen;
            }

            return EStreamError::eErrorNone;
        }

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

            if (!(*this->view_.get()))
            {
                return EStreamError::eErrorStreamNotOpen;
            }

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

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

        inline virtual void Close() override
        {
            this->view_.reset();
        }

    private:
        AuSPtr<Memory::MemoryViewRead> view_;
    };
}