AuroraRuntime/Source/Compression/IngestableReadBase.inl

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

    File: IngestableReadBase.inl
    Date: 2022-2-14
    Author: Reece
***/
#pragma once

namespace Aurora::Compression
{
    template<typename T, AuUInt Z>
    void IngestableReadBase::SetArray(T(&array)[Z])
    {
        this->internalInBuffer_ = reinterpret_cast<AuUInt8 *>(array);
        this->internalInLength_ = Z;
    }

    void IngestableReadBase::SetPointer(void *pointer, AuUInt32 length)
    {
        this->internalInBuffer_ = reinterpret_cast<AuUInt8 *>(pointer);
        this->internalInLength_ = length;
    }

    // Given a zlib-like interface input paremeters, a stream source, and a buffer...
    //
    // ...reads
    template<typename T, typename Z>
    AuUInt32 IngestableReadBase::IngestForInPointer(const AuSPtr<IO::IStreamReader> &reader, T *&in, Z &inAlreadyAvailable, AuUInt32 amount)
    {
        if (inAlreadyAvailable > this->internalInLength_)
        {
            SysPanic("Invalid Buffer Position");
        }

        AuUInt32 currentOffset {};
        if (in && inAlreadyAvailable)
        {
            currentOffset = reinterpret_cast<const AuUInt8 *>(in) - this->internalInBuffer_;
        }

        currentOffset += inAlreadyAvailable;

        AuUInt32 currentLength = this->internalInLength_ - currentOffset;
        if (currentLength > this->internalInLength_)
        {
            SysPanic("Invalid Buffer Position");
        }

        auto nextStreamRead    = this->internalInBuffer_ + currentOffset;
        auto nextStreamSegment = this->internalInBuffer_ + inAlreadyAvailable;

        AuUInt read = AuMin(amount, currentLength);
        if (reader->Read(AuMemoryViewStreamWrite(this->internalInBuffer_ + currentOffset, this->internalInBuffer_ + read, read)) != IO::EStreamError::eErrorNone)
        {
            return 0;
        }

        in = (T *)(this->internalInBuffer_ + currentOffset);
        inAlreadyAvailable += read;

        return read;
    }
}