qt-everywhere-src-5.14.1/qtmultimedia/src/plugins/directshow/common/directshowmediatypeenum.cpp

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#include "directshowmediatypeenum.h"

#include "directshowpin.h"

DirectShowMediaTypeEnum::DirectShowMediaTypeEnum(DirectShowPin *pin)
    : m_mediaTypes(pin->supportedMediaTypes())
{
    m_pin->AddRef();
}

DirectShowMediaTypeEnum::DirectShowMediaTypeEnum(const QList<DirectShowMediaType> &types)
    : m_mediaTypes(types)
{
}

DirectShowMediaTypeEnum::~DirectShowMediaTypeEnum()
{
    if (m_pin)
        m_pin->Release();
}

HRESULT DirectShowMediaTypeEnum::QueryInterface(REFIID riid, void **ppv)
{
    if (ppv == nullptr)
        return E_POINTER;
    if (riid == IID_IUnknown)
        *ppv = static_cast<IUnknown *>(this);
    else if (riid == IID_IEnumMediaTypes)
        *ppv = static_cast<IEnumMediaTypes *>(this);
    else
        return E_NOINTERFACE;
    AddRef();
    return S_OK;
}

HRESULT DirectShowMediaTypeEnum::Next(ULONG cMediaTypes, AM_MEDIA_TYPE **ppMediaTypes, ULONG *pcFetched)
{
    if (!ppMediaTypes || (!pcFetched && cMediaTypes != 1))
        return E_POINTER;

    ULONG count = qBound<ULONG>(0, cMediaTypes, m_mediaTypes.count() - m_index);

    for (ULONG i = 0; i < count; ++i, ++m_index) {
        ppMediaTypes[i] = reinterpret_cast<AM_MEDIA_TYPE *>(CoTaskMemAlloc(sizeof(AM_MEDIA_TYPE)));
        DirectShowMediaType::copyToUninitialized(ppMediaTypes[i], &m_mediaTypes.at(m_index));
    }

    if (pcFetched)
        *pcFetched = count;

    return count == cMediaTypes ? S_OK : S_FALSE;
}

HRESULT DirectShowMediaTypeEnum::Skip(ULONG cMediaTypes)
{
    m_index = qMin(int(m_index + cMediaTypes), m_mediaTypes.count());
    return m_index < m_mediaTypes.count() ? S_OK : S_FALSE;
}

HRESULT DirectShowMediaTypeEnum::Reset()
{
    m_index = 0;
    return S_OK;
}

HRESULT DirectShowMediaTypeEnum::Clone(IEnumMediaTypes **ppEnum)
{
    if (!ppEnum)
        return E_POINTER;
    *ppEnum = m_pin ? new DirectShowMediaTypeEnum(m_pin) : new DirectShowMediaTypeEnum(m_mediaTypes);
    return S_OK;
}