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#include "directshowpinenum.h"

#include <QtMultimedia>

DirectShowPinEnum::DirectShowPinEnum(const QList<IPin *> &pins)
    : m_ref(1)
    , m_pins(pins)
    , m_index(0)
{
    foreach (IPin *pin, m_pins)
        pin->AddRef();
}

DirectShowPinEnum::~DirectShowPinEnum()
{
    foreach (IPin *pin, m_pins)
        pin->Release();
}

HRESULT DirectShowPinEnum::QueryInterface(REFIID riid, void **ppvObject)
{
    if (riid == IID_IUnknown
            || riid == IID_IEnumPins) {
        AddRef();

        *ppvObject = static_cast<IEnumPins *>(this);

        return S_OK;
    } else {
        *ppvObject = 0;

        return E_NOINTERFACE;
    }
}

ULONG DirectShowPinEnum::AddRef()
{
    return InterlockedIncrement(&m_ref);
}

ULONG DirectShowPinEnum::Release()
{
    ULONG ref = InterlockedDecrement(&m_ref);

    if (ref == 0) {
        delete this;
    }

    return ref;
}

HRESULT DirectShowPinEnum::Next(ULONG cPins, IPin **ppPins, ULONG *pcFetched)
{
    if (ppPins && (pcFetched || cPins == 1)) {
        ULONG count = qBound<ULONG>(0, cPins, m_pins.count() - m_index);

        for (ULONG i = 0; i < count; ++i, ++m_index) {
            ppPins[i] = m_pins.at(m_index);
            ppPins[i]->AddRef();
        }

        if (pcFetched)
            *pcFetched = count;

        return count == cPins ? S_OK : S_FALSE;
    } else {
        return E_POINTER;
    }
}

HRESULT DirectShowPinEnum::Skip(ULONG cPins)
{
    m_index = qMin(int(m_index + cPins), m_pins.count());

    return m_index < m_pins.count() ? S_OK : S_FALSE;
}

HRESULT DirectShowPinEnum::Reset()
{
    m_index = 0;

    return S_OK;
}

HRESULT DirectShowPinEnum::Clone(IEnumPins **ppEnum)
{
    if (ppEnum) {
        *ppEnum = new DirectShowPinEnum(m_pins);

        return S_OK;
    } else {
        return E_POINTER;
    }
}