CPipeBlock.cpp

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#include "stdafx.h"

namespace AxPipe {
    CPipeBlock::CPipeBlock() {
        Init(0);
    }

    CPipeBlock::~CPipeBlock() {
        if (m_pBlockPart) {
            m_pBlockPart->Release();
        }
    }
    
    CPipeBlock *
    CPipeBlock::Init(size_t cbBlockSize) {
        m_cbBlockSize = cbBlockSize;
        m_pBlockPart = NULL;
        return this;
    }

    void
    CPipeBlock::OutPump(CSeg *pSeg) {
        // Propagate end of stream, and exit directly. We can never have a full output-block
        // waiting at this stage, if it's end of stream - this will have to be picked up by
        // the OutClose() function. It might also be a special block, those we send as-is.
        if (!CSeg::IsSeg(pSeg)) {
            CPipe::OutPump(pSeg);
            return;
        }

        if (m_pBlockPart) {
            size_t cbToMove = m_cbBlockSize - m_pBlockPart->Len();

            // Adjust if we don't get enough for a full block
            if (cbToMove > pSeg->Len()) {
                cbToMove = pSeg->Len();
            }
            CopyMemory(&m_pBlockPart->PtrWr()[m_pBlockPart->Len()], pSeg->PtrRd(), cbToMove);
            m_pBlockPart->Len(m_pBlockPart->Len() + cbToMove);
            pSeg->Drop(cbToMove);

            // If we do have a block
            if (m_pBlockPart->Len() == m_cbBlockSize) {
                CPipe::OutPump(m_pBlockPart);
                m_pBlockPart = NULL;
            }
        }
        // Now we know that m_pBlockPart is NULL, let see if we can send more.

        // Now output as much as possible. Create a clone, and make it an even multiple of
        // the block size in length. Only do it if there's enough for at least a block.
        if (pSeg->Len() >= m_cbBlockSize) {
            CSeg *pBlockSeg = pSeg->Clone();
            pBlockSeg->Len(pSeg->Len() - pSeg->Len() % m_cbBlockSize);
            pSeg->Drop(pBlockSeg->Len());
            CPipe::OutPump(pBlockSeg);
        }

        if (pSeg->Len()) {
            // There's a partial block left, make a new segment, one block large, and put it there.
            m_pBlockPart = new CSeg(pSeg->PtrRd(), pSeg->Len(), m_cbBlockSize - pSeg->Len());
        }
        pSeg->Release();            
    }
    
    CSeg *
    CPipeBlock::PartialBlock() {
        return m_pBlockPart;
    }
};

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