Function GDALResampleChunk_ModeT

gcore/overview.cpp:2341–2612

template <class T>
static CPLErr GDALResampleChunk_ModeT(const GDALOverviewResampleArgs &args,
                                      const T *pChunk, T *const pDstBuffer)

{
    const double dfXRatioDstToSrc = args.dfXRatioDstToSrc;
    const double dfYRatioDstToSrc = args.dfYRatioDstToSrc;
    const double dfSrcXDelta = args.dfSrcXDelta;
    const double dfSrcYDelta = args.dfSrcYDelta;
    const GByte *pabyChunkNodataMask = args.pabyChunkNodataMask;
    const int nChunkXOff = args.nChunkXOff;
    const int nChunkXSize = args.nChunkXSize;
    const int nChunkYOff = args.nChunkYOff;
    const int nChunkYSize = args.nChunkYSize;
    const int nDstXOff = args.nDstXOff;
    const int nDstXOff2 = args.nDstXOff2;
    const int nDstYOff = args.nDstYOff;
    const int nDstYOff2 = args.nDstYOff2;
    const bool bHasNoData = args.bHasNoData;
    const GDALColorTable *poColorTable = args.poColorTable;
    const int nDstXSize = nDstXOff2 - nDstXOff;

    T tNoDataValue;
    if constexpr (std::is_same<T, ComplexFloat16>::value)
    {
        tNoDataValue.r = cpl::NumericLimits<GFloat16>::quiet_NaN();
        tNoDataValue.i = cpl::NumericLimits<GFloat16>::quiet_NaN();
    }
    else if constexpr (std::is_same<T, std::complex<float>>::value ||
                       std::is_same<T, std::complex<double>>::value)
    {
        using BaseT = typename T::value_type;
        tNoDataValue =
            std::complex<BaseT>(std::numeric_limits<BaseT>::quiet_NaN(),
                                std::numeric_limits<BaseT>::quiet_NaN());
    }
    else if (!bHasNoData || !GDALIsValueInRange<T>(args.dfNoDataValue))
        tNoDataValue = 0;
    else
        tNoDataValue = static_cast<T>(args.dfNoDataValue);

    using CountType = uint32_t;
    CountType nMaxNumPx = 0;
    T *paVals = nullptr;
    CountType *panCounts = nullptr;

    const int nChunkRightXOff = nChunkXOff + nChunkXSize;
    const int nChunkBottomYOff = nChunkYOff + nChunkYSize;
    std::vector<int> anVals(256, 0);

    /* ==================================================================== */
    /*      Loop over destination scanlines.                                */
    /* ==================================================================== */
    for (int iDstLine = nDstYOff; iDstLine < nDstYOff2; ++iDstLine)
    {
        const double dfSrcYOff = dfSrcYDelta + iDstLine * dfYRatioDstToSrc;
        int nSrcYOff = static_cast<int>(dfSrcYOff + 1e-8);
#ifdef only_pixels_with_more_than_10_pct_participation
        // When oversampling, don't take into account pixels that have a tiny