/******************************************************************************
 *
 * Project:  GDAL
 * Purpose:  Implementation of a set of GDALDerivedPixelFunc(s) to be used
 *           with source raster band of virtual GDAL datasets.
 * Author:   Antonio Valentino <antonio.valentino@tiscali.it>
 *
 ******************************************************************************
 * Copyright (c) 2008-2014,2022 Antonio Valentino <antonio.valentino@tiscali.it>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *****************************************************************************/

#include <cmath>
#include "gdal.h"
#include "vrtdataset.h"

#include <limits>

template <typename T>
inline double GetSrcVal(const void *pSource, GDALDataType eSrcType, T ii)
{
    switch (eSrcType)
    {
        case GDT_Unknown:
            return 0;
        case GDT_Byte:
            return static_cast<const GByte *>(pSource)[ii];
        case GDT_Int8:
            return static_cast<const GInt8 *>(pSource)[ii];
        case GDT_UInt16:
            return static_cast<const GUInt16 *>(pSource)[ii];
        case GDT_Int16:
            return static_cast<const GInt16 *>(pSource)[ii];
        case GDT_UInt32:
            return static_cast<const GUInt32 *>(pSource)[ii];
        case GDT_Int32:
            return static_cast<const GInt32 *>(pSource)[ii];
        // Precision loss currently for int64/uint64
        case GDT_UInt64:
            return static_cast<double>(
                static_cast<const uint64_t *>(pSource)[ii]);
        case GDT_Int64:
            return static_cast<double>(
                static_cast<const int64_t *>(pSource)[ii]);
        case GDT_Float32:
            return static_cast<const float *>(pSource)[ii];
        case GDT_Float64:
            return static_cast<const double *>(pSource)[ii];
        case GDT_CInt16:
            return static_cast<const GInt16 *>(pSource)[2 * ii];
        case GDT_CInt32:
            return static_cast<const GInt32 *>(pSource)[2 * ii];
        case GDT_CFloat32:
            return static_cast<const float *>(pSource)[2 * ii];
        case GDT_CFloat64:
            return static_cast<const double *>(pSource)[2 * ii];
        case GDT_TypeCount:
            break;
    }
    return 0;
}

static CPLErr FetchDoubleArg(CSLConstList papszArgs, const char *pszName,
                             double *pdfX, double *pdfDefault = nullptr)
{
    const char *pszVal = CSLFetchNameValue(papszArgs, pszName);

    if (pszVal == nullptr)
    {
        if (pdfDefault == nullptr)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Missing pixel function argument: %s", pszName);
            return CE_Failure;
        }
        else
        {
            *pdfX = *pdfDefault;
            return CE_None;
        }
    }

    char *pszEnd = nullptr;
    *pdfX = std::strtod(pszVal, &pszEnd);
    if (pszEnd == pszVal)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Failed to parse pixel function argument: %s", pszName);
        return CE_Failure;
    }

    return CE_None;
}

static CPLErr RealPixelFunc(void **papoSources, int nSources, void *pData,
                            int nXSize, int nYSize, GDALDataType eSrcType,
                            GDALDataType eBufType, int nPixelSpace,
                            int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;

    const int nPixelSpaceSrc = GDALGetDataTypeSizeBytes(eSrcType);
    const size_t nLineSpaceSrc = static_cast<size_t>(nPixelSpaceSrc) * nXSize;

    /* ---- Set pixels ---- */
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        GDALCopyWords(static_cast<GByte *>(papoSources[0]) +
                          nLineSpaceSrc * iLine,
                      eSrcType, nPixelSpaceSrc,
                      static_cast<GByte *>(pData) +
                          static_cast<GSpacing>(nLineSpace) * iLine,
                      eBufType, nPixelSpace, nXSize);
    }

    /* ---- Return success ---- */
    return CE_None;
}  // RealPixelFunc

static CPLErr ImagPixelFunc(void **papoSources, int nSources, void *pData,
                            int nXSize, int nYSize, GDALDataType eSrcType,
                            GDALDataType eBufType, int nPixelSpace,
                            int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;

    if (GDALDataTypeIsComplex(eSrcType))
    {
        const GDALDataType eSrcBaseType = GDALGetNonComplexDataType(eSrcType);
        const int nPixelSpaceSrc = GDALGetDataTypeSizeBytes(eSrcType);
        const size_t nLineSpaceSrc =
            static_cast<size_t>(nPixelSpaceSrc) * nXSize;

        const void *const pImag = static_cast<GByte *>(papoSources[0]) +
                                  GDALGetDataTypeSizeBytes(eSrcType) / 2;

        /* ---- Set pixels ---- */
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            GDALCopyWords(static_cast<const GByte *>(pImag) +
                              nLineSpaceSrc * iLine,
                          eSrcBaseType, nPixelSpaceSrc,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine,
                          eBufType, nPixelSpace, nXSize);
        }
    }
    else
    {
        const double dfImag = 0;

        /* ---- Set pixels ---- */
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            // Always copy from the same location.
            GDALCopyWords(&dfImag, eSrcType, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine,
                          eBufType, nPixelSpace, nXSize);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // ImagPixelFunc

static CPLErr ComplexPixelFunc(void **papoSources, int nSources, void *pData,
                               int nXSize, int nYSize, GDALDataType eSrcType,
                               GDALDataType eBufType, int nPixelSpace,
                               int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 2)
        return CE_Failure;

    const void *const pReal = papoSources[0];
    const void *const pImag = papoSources[1];

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            // Source raster pixels may be obtained with GetSrcVal macro.
            const double adfPixVal[2] = {
                GetSrcVal(pReal, eSrcType, ii),  // re
                GetSrcVal(pImag, eSrcType, ii)   // im
            };

            GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // ComplexPixelFunc

typedef enum
{
    GAT_amplitude,
    GAT_intensity,
    GAT_dB
} PolarAmplitudeType;

static const char pszPolarPixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument name='amplitude_type' description='Amplitude Type' "
    "type='string-select' default='AMPLITUDE'>"
    "       <Value>INTENSITY</Value>"
    "       <Value>dB</Value>"
    "       <Value>AMPLITUDE</Value>"
    "   </Argument>"
    "</PixelFunctionArgumentsList>";

static CPLErr PolarPixelFunc(void **papoSources, int nSources, void *pData,
                             int nXSize, int nYSize, GDALDataType eSrcType,
                             GDALDataType eBufType, int nPixelSpace,
                             int nLineSpace, CSLConstList papszArgs)
{
    /* ---- Init ---- */
    if (nSources != 2)
        return CE_Failure;

    const char pszName[] = "amplitude_type";
    const char *pszVal = CSLFetchNameValue(papszArgs, pszName);
    PolarAmplitudeType amplitudeType = GAT_amplitude;
    if (pszVal != nullptr)
    {
        if (strcmp(pszVal, "INTENSITY") == 0)
            amplitudeType = GAT_intensity;
        else if (strcmp(pszVal, "dB") == 0)
            amplitudeType = GAT_dB;
        else if (strcmp(pszVal, "AMPLITUDE") != 0)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Invalid value for pixel function argument '%s': %s",
                     pszName, pszVal);
            return CE_Failure;
        }
    }

    const void *const pAmp = papoSources[0];
    const void *const pPhase = papoSources[1];

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            // Source raster pixels may be obtained with GetSrcVal macro.
            double dfAmp = GetSrcVal(pAmp, eSrcType, ii);
            switch (amplitudeType)
            {
                case GAT_intensity:
                    // clip to zero
                    dfAmp = dfAmp <= 0 ? 0 : std::sqrt(dfAmp);
                    break;
                case GAT_dB:
                    dfAmp = dfAmp <= 0
                                ? -std::numeric_limits<double>::infinity()
                                : pow(10, dfAmp / 20.);
                    break;
                case GAT_amplitude:
                    break;
            }
            const double dfPhase = GetSrcVal(pPhase, eSrcType, ii);
            const double adfPixVal[2] = {
                dfAmp * std::cos(dfPhase),  // re
                dfAmp * std::sin(dfPhase)   // im
            };

            GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // PolarPixelFunc

static CPLErr ModulePixelFunc(void **papoSources, int nSources, void *pData,
                              int nXSize, int nYSize, GDALDataType eSrcType,
                              GDALDataType eBufType, int nPixelSpace,
                              int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;

    if (GDALDataTypeIsComplex(eSrcType))
    {
        const void *pReal = papoSources[0];
        const void *pImag = static_cast<GByte *>(papoSources[0]) +
                            GDALGetDataTypeSizeBytes(eSrcType) / 2;

        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfReal = GetSrcVal(pReal, eSrcType, ii);
                const double dfImag = GetSrcVal(pImag, eSrcType, ii);

                const double dfPixVal = sqrt(dfReal * dfReal + dfImag * dfImag);

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfPixVal =
                    fabs(GetSrcVal(papoSources[0], eSrcType, ii));

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // ModulePixelFunc

static CPLErr PhasePixelFunc(void **papoSources, int nSources, void *pData,
                             int nXSize, int nYSize, GDALDataType eSrcType,
                             GDALDataType eBufType, int nPixelSpace,
                             int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;

    if (GDALDataTypeIsComplex(eSrcType))
    {
        const void *const pReal = papoSources[0];
        const void *const pImag = static_cast<GByte *>(papoSources[0]) +
                                  GDALGetDataTypeSizeBytes(eSrcType) / 2;

        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfReal = GetSrcVal(pReal, eSrcType, ii);
                const double dfImag = GetSrcVal(pImag, eSrcType, ii);

                const double dfPixVal = atan2(dfImag, dfReal);

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else if (GDALDataTypeIsInteger(eSrcType) && !GDALDataTypeIsSigned(eSrcType))
    {
        constexpr double dfZero = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            GDALCopyWords(&dfZero, GDT_Float64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine,
                          eBufType, nPixelSpace, nXSize);
        }
    }
    else
    {
        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                const void *const pReal = papoSources[0];

                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfReal = GetSrcVal(pReal, eSrcType, ii);
                const double dfPixVal = (dfReal < 0) ? M_PI : 0.0;

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // PhasePixelFunc

static CPLErr ConjPixelFunc(void **papoSources, int nSources, void *pData,
                            int nXSize, int nYSize, GDALDataType eSrcType,
                            GDALDataType eBufType, int nPixelSpace,
                            int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;

    if (GDALDataTypeIsComplex(eSrcType) && GDALDataTypeIsComplex(eBufType))
    {
        const int nOffset = GDALGetDataTypeSizeBytes(eSrcType) / 2;
        const void *const pReal = papoSources[0];
        const void *const pImag =
            static_cast<GByte *>(papoSources[0]) + nOffset;

        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double adfPixVal[2] = {
                    +GetSrcVal(pReal, eSrcType, ii),  // re
                    -GetSrcVal(pImag, eSrcType, ii)   // im
                };

                GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        // No complex data type.
        return RealPixelFunc(papoSources, nSources, pData, nXSize, nYSize,
                             eSrcType, eBufType, nPixelSpace, nLineSpace);
    }

    /* ---- Return success ---- */
    return CE_None;
}  // ConjPixelFunc

static const char pszSumPixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument name='k' description='Optional constant term' type='double' "
    "default='0.0' />"
    "</PixelFunctionArgumentsList>";

static CPLErr SumPixelFunc(void **papoSources, int nSources, void *pData,
                           int nXSize, int nYSize, GDALDataType eSrcType,
                           GDALDataType eBufType, int nPixelSpace,
                           int nLineSpace, CSLConstList papszArgs)
{
    /* ---- Init ---- */
    if (nSources < 2)
        return CE_Failure;

    double dfK = 0.0;
    if (FetchDoubleArg(papszArgs, "k", &dfK, &dfK) != CE_None)
        return CE_Failure;

    /* ---- Set pixels ---- */
    if (GDALDataTypeIsComplex(eSrcType))
    {
        const int nOffset = GDALGetDataTypeSizeBytes(eSrcType) / 2;

        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                double adfSum[2] = {dfK, 0.0};

                for (int iSrc = 0; iSrc < nSources; ++iSrc)
                {
                    const void *const pReal = papoSources[iSrc];
                    const void *const pImag =
                        static_cast<const GByte *>(pReal) + nOffset;

                    // Source raster pixels may be obtained with GetSrcVal
                    // macro.
                    adfSum[0] += GetSrcVal(pReal, eSrcType, ii);
                    adfSum[1] += GetSrcVal(pImag, eSrcType, ii);
                }

                GDALCopyWords(adfSum, GDT_CFloat64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                double dfSum = dfK;  // Not complex.

                for (int iSrc = 0; iSrc < nSources; ++iSrc)
                {
                    // Source raster pixels may be obtained with GetSrcVal
                    // macro.
                    dfSum += GetSrcVal(papoSources[iSrc], eSrcType, ii);
                }

                GDALCopyWords(&dfSum, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
} /* SumPixelFunc */

static CPLErr DiffPixelFunc(void **papoSources, int nSources, void *pData,
                            int nXSize, int nYSize, GDALDataType eSrcType,
                            GDALDataType eBufType, int nPixelSpace,
                            int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 2)
        return CE_Failure;

    if (GDALDataTypeIsComplex(eSrcType))
    {
        const int nOffset = GDALGetDataTypeSizeBytes(eSrcType) / 2;
        const void *const pReal0 = papoSources[0];
        const void *const pImag0 =
            static_cast<GByte *>(papoSources[0]) + nOffset;
        const void *const pReal1 = papoSources[1];
        const void *const pImag1 =
            static_cast<GByte *>(papoSources[1]) + nOffset;

        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                double adfPixVal[2] = {GetSrcVal(pReal0, eSrcType, ii) -
                                           GetSrcVal(pReal1, eSrcType, ii),
                                       GetSrcVal(pImag0, eSrcType, ii) -
                                           GetSrcVal(pImag1, eSrcType, ii)};

                GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                // Not complex.
                const double dfPixVal =
                    GetSrcVal(papoSources[0], eSrcType, ii) -
                    GetSrcVal(papoSources[1], eSrcType, ii);

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // DiffPixelFunc

static const char pszMulPixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument name='k' description='Optional constant factor' "
    "type='double' default='1.0' />"
    "</PixelFunctionArgumentsList>";

static CPLErr MulPixelFunc(void **papoSources, int nSources, void *pData,
                           int nXSize, int nYSize, GDALDataType eSrcType,
                           GDALDataType eBufType, int nPixelSpace,
                           int nLineSpace, CSLConstList papszArgs)
{
    /* ---- Init ---- */
    if (nSources < 2)
        return CE_Failure;

    double dfK = 1.0;
    if (FetchDoubleArg(papszArgs, "k", &dfK, &dfK) != CE_None)
        return CE_Failure;

    /* ---- Set pixels ---- */
    if (GDALDataTypeIsComplex(eSrcType))
    {
        const int nOffset = GDALGetDataTypeSizeBytes(eSrcType) / 2;

        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                double adfPixVal[2] = {dfK, 0.0};

                for (int iSrc = 0; iSrc < nSources; ++iSrc)
                {
                    const void *const pReal = papoSources[iSrc];
                    const void *const pImag =
                        static_cast<const GByte *>(pReal) + nOffset;

                    const double dfOldR = adfPixVal[0];
                    const double dfOldI = adfPixVal[1];

                    // Source raster pixels may be obtained with GetSrcVal
                    // macro.
                    const double dfNewR = GetSrcVal(pReal, eSrcType, ii);
                    const double dfNewI = GetSrcVal(pImag, eSrcType, ii);

                    adfPixVal[0] = dfOldR * dfNewR - dfOldI * dfNewI;
                    adfPixVal[1] = dfOldR * dfNewI + dfOldI * dfNewR;
                }

                GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                double dfPixVal = dfK;  // Not complex.

                for (int iSrc = 0; iSrc < nSources; ++iSrc)
                {
                    // Source raster pixels may be obtained with GetSrcVal
                    // macro.
                    dfPixVal *= GetSrcVal(papoSources[iSrc], eSrcType, ii);
                }

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // MulPixelFunc

static CPLErr DivPixelFunc(void **papoSources, int nSources, void *pData,
                           int nXSize, int nYSize, GDALDataType eSrcType,
                           GDALDataType eBufType, int nPixelSpace,
                           int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 2)
        return CE_Failure;

    /* ---- Set pixels ---- */
    if (GDALDataTypeIsComplex(eSrcType))
    {
        const int nOffset = GDALGetDataTypeSizeBytes(eSrcType) / 2;
        const void *const pReal0 = papoSources[0];
        const void *const pImag0 =
            static_cast<GByte *>(papoSources[0]) + nOffset;
        const void *const pReal1 = papoSources[1];
        const void *const pImag1 =
            static_cast<GByte *>(papoSources[1]) + nOffset;

        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfReal0 = GetSrcVal(pReal0, eSrcType, ii);
                const double dfReal1 = GetSrcVal(pReal1, eSrcType, ii);
                const double dfImag0 = GetSrcVal(pImag0, eSrcType, ii);
                const double dfImag1 = GetSrcVal(pImag1, eSrcType, ii);
                const double dfAux = dfReal1 * dfReal1 + dfImag1 * dfImag1;

                const double adfPixVal[2] = {
                    dfAux == 0
                        ? std::numeric_limits<double>::infinity()
                        : dfReal0 * dfReal1 / dfAux + dfImag0 * dfImag1 / dfAux,
                    dfAux == 0 ? std::numeric_limits<double>::infinity()
                               : dfReal1 / dfAux * dfImag0 -
                                     dfReal0 * dfImag1 / dfAux};

                GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                const double dfVal = GetSrcVal(papoSources[1], eSrcType, ii);
                double dfPixVal =
                    dfVal == 0
                        ? std::numeric_limits<double>::infinity()
                        : GetSrcVal(papoSources[0], eSrcType, ii) / dfVal;

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // DivPixelFunc

static CPLErr CMulPixelFunc(void **papoSources, int nSources, void *pData,
                            int nXSize, int nYSize, GDALDataType eSrcType,
                            GDALDataType eBufType, int nPixelSpace,
                            int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 2)
        return CE_Failure;

    /* ---- Set pixels ---- */
    if (GDALDataTypeIsComplex(eSrcType))
    {
        const int nOffset = GDALGetDataTypeSizeBytes(eSrcType) / 2;
        const void *const pReal0 = papoSources[0];
        const void *const pImag0 =
            static_cast<GByte *>(papoSources[0]) + nOffset;
        const void *const pReal1 = papoSources[1];
        const void *const pImag1 =
            static_cast<GByte *>(papoSources[1]) + nOffset;

        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfReal0 = GetSrcVal(pReal0, eSrcType, ii);
                const double dfReal1 = GetSrcVal(pReal1, eSrcType, ii);
                const double dfImag0 = GetSrcVal(pImag0, eSrcType, ii);
                const double dfImag1 = GetSrcVal(pImag1, eSrcType, ii);
                const double adfPixVal[2] = {
                    dfReal0 * dfReal1 + dfImag0 * dfImag1,
                    dfReal1 * dfImag0 - dfReal0 * dfImag1};

                GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                // Not complex.
                const double adfPixVal[2] = {
                    GetSrcVal(papoSources[0], eSrcType, ii) *
                        GetSrcVal(papoSources[1], eSrcType, ii),
                    0.0};

                GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // CMulPixelFunc

static const char pszInvPixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument name='k' description='Optional constant factor' "
    "type='double' default='1.0' />"
    "</PixelFunctionArgumentsList>";

static CPLErr InvPixelFunc(void **papoSources, int nSources, void *pData,
                           int nXSize, int nYSize, GDALDataType eSrcType,
                           GDALDataType eBufType, int nPixelSpace,
                           int nLineSpace, CSLConstList papszArgs)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;

    double dfK = 1.0;
    if (FetchDoubleArg(papszArgs, "k", &dfK, &dfK) != CE_None)
        return CE_Failure;

    /* ---- Set pixels ---- */
    if (GDALDataTypeIsComplex(eSrcType))
    {
        const int nOffset = GDALGetDataTypeSizeBytes(eSrcType) / 2;
        const void *const pReal = papoSources[0];
        const void *const pImag =
            static_cast<GByte *>(papoSources[0]) + nOffset;

        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfReal = GetSrcVal(pReal, eSrcType, ii);
                const double dfImag = GetSrcVal(pImag, eSrcType, ii);
                const double dfAux = dfReal * dfReal + dfImag * dfImag;
                const double adfPixVal[2] = {
                    dfAux == 0 ? std::numeric_limits<double>::infinity()
                               : dfK * dfReal / dfAux,
                    dfAux == 0 ? std::numeric_limits<double>::infinity()
                               : -dfK * dfImag / dfAux};

                GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                // Not complex.
                const double dfVal = GetSrcVal(papoSources[0], eSrcType, ii);
                const double dfPixVal =
                    dfVal == 0 ? std::numeric_limits<double>::infinity()
                               : dfK / dfVal;

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // InvPixelFunc

static CPLErr IntensityPixelFunc(void **papoSources, int nSources, void *pData,
                                 int nXSize, int nYSize, GDALDataType eSrcType,
                                 GDALDataType eBufType, int nPixelSpace,
                                 int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;

    if (GDALDataTypeIsComplex(eSrcType))
    {
        const int nOffset = GDALGetDataTypeSizeBytes(eSrcType) / 2;
        const void *const pReal = papoSources[0];
        const void *const pImag =
            static_cast<GByte *>(papoSources[0]) + nOffset;

        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfReal = GetSrcVal(pReal, eSrcType, ii);
                const double dfImag = GetSrcVal(pImag, eSrcType, ii);

                const double dfPixVal = dfReal * dfReal + dfImag * dfImag;

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                double dfPixVal = GetSrcVal(papoSources[0], eSrcType, ii);
                dfPixVal *= dfPixVal;

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // IntensityPixelFunc

static CPLErr SqrtPixelFunc(void **papoSources, int nSources, void *pData,
                            int nXSize, int nYSize, GDALDataType eSrcType,
                            GDALDataType eBufType, int nPixelSpace,
                            int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;
    if (GDALDataTypeIsComplex(eSrcType))
        return CE_Failure;

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            // Source raster pixels may be obtained with GetSrcVal macro.
            const double dfPixVal =
                sqrt(GetSrcVal(papoSources[0], eSrcType, ii));

            GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // SqrtPixelFunc

static CPLErr Log10PixelFuncHelper(void **papoSources, int nSources,
                                   void *pData, int nXSize, int nYSize,
                                   GDALDataType eSrcType, GDALDataType eBufType,
                                   int nPixelSpace, int nLineSpace, double fact)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;

    if (GDALDataTypeIsComplex(eSrcType))
    {
        // Complex input datatype.
        const int nOffset = GDALGetDataTypeSizeBytes(eSrcType) / 2;
        const void *const pReal = papoSources[0];
        const void *const pImag =
            static_cast<GByte *>(papoSources[0]) + nOffset;

        /* We should compute fact * log10( sqrt( dfReal * dfReal + dfImag *
         * dfImag ) ) */
        /* Given that log10(sqrt(x)) = 0.5 * log10(x) */
        /* we can remove the sqrt() by multiplying fact by 0.5 */
        fact *= 0.5;

        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfReal = GetSrcVal(pReal, eSrcType, ii);
                const double dfImag = GetSrcVal(pImag, eSrcType, ii);

                const double dfPixVal =
                    fact * log10(dfReal * dfReal + dfImag * dfImag);

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }
    else
    {
        /* ---- Set pixels ---- */
        size_t ii = 0;
        for (int iLine = 0; iLine < nYSize; ++iLine)
        {
            for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
            {
                // Source raster pixels may be obtained with GetSrcVal macro.
                const double dfPixVal =
                    fact * log10(fabs(GetSrcVal(papoSources[0], eSrcType, ii)));

                GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                              static_cast<GByte *>(pData) +
                                  static_cast<GSpacing>(nLineSpace) * iLine +
                                  iCol * nPixelSpace,
                              eBufType, nPixelSpace, 1);
            }
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // Log10PixelFuncHelper

static CPLErr Log10PixelFunc(void **papoSources, int nSources, void *pData,
                             int nXSize, int nYSize, GDALDataType eSrcType,
                             GDALDataType eBufType, int nPixelSpace,
                             int nLineSpace)
{
    return Log10PixelFuncHelper(papoSources, nSources, pData, nXSize, nYSize,
                                eSrcType, eBufType, nPixelSpace, nLineSpace,
                                1.0);
}  // Log10PixelFunc

static const char pszDBPixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument name='fact' description='Factor' type='double' "
    "default='20.0' />"
    "</PixelFunctionArgumentsList>";

static CPLErr DBPixelFunc(void **papoSources, int nSources, void *pData,
                          int nXSize, int nYSize, GDALDataType eSrcType,
                          GDALDataType eBufType, int nPixelSpace,
                          int nLineSpace, CSLConstList papszArgs)
{
    double dfFact = 20.;
    if (FetchDoubleArg(papszArgs, "fact", &dfFact, &dfFact) != CE_None)
        return CE_Failure;

    return Log10PixelFuncHelper(papoSources, nSources, pData, nXSize, nYSize,
                                eSrcType, eBufType, nPixelSpace, nLineSpace,
                                dfFact);
}  // DBPixelFunc

static CPLErr ExpPixelFuncHelper(void **papoSources, int nSources, void *pData,
                                 int nXSize, int nYSize, GDALDataType eSrcType,
                                 GDALDataType eBufType, int nPixelSpace,
                                 int nLineSpace, double base, double fact)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;
    if (GDALDataTypeIsComplex(eSrcType))
        return CE_Failure;

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            // Source raster pixels may be obtained with GetSrcVal macro.
            const double dfPixVal =
                pow(base, GetSrcVal(papoSources[0], eSrcType, ii) * fact);

            GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // ExpPixelFuncHelper

static const char pszExpPixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument name='base' description='Base' type='double' "
    "default='2.7182818284590452353602874713526624' />"
    "   <Argument name='fact' description='Factor' type='double' default='1' />"
    "</PixelFunctionArgumentsList>";

static CPLErr ExpPixelFunc(void **papoSources, int nSources, void *pData,
                           int nXSize, int nYSize, GDALDataType eSrcType,
                           GDALDataType eBufType, int nPixelSpace,
                           int nLineSpace, CSLConstList papszArgs)
{
    double dfBase = 2.7182818284590452353602874713526624;
    double dfFact = 1.;

    if (FetchDoubleArg(papszArgs, "base", &dfBase, &dfBase) != CE_None)
        return CE_Failure;

    if (FetchDoubleArg(papszArgs, "fact", &dfFact, &dfFact) != CE_None)
        return CE_Failure;

    return ExpPixelFuncHelper(papoSources, nSources, pData, nXSize, nYSize,
                              eSrcType, eBufType, nPixelSpace, nLineSpace,
                              dfBase, dfFact);
}  // ExpPixelFunc

static CPLErr dB2AmpPixelFunc(void **papoSources, int nSources, void *pData,
                              int nXSize, int nYSize, GDALDataType eSrcType,
                              GDALDataType eBufType, int nPixelSpace,
                              int nLineSpace)
{
    return ExpPixelFuncHelper(papoSources, nSources, pData, nXSize, nYSize,
                              eSrcType, eBufType, nPixelSpace, nLineSpace, 10.0,
                              1. / 20);
}  // dB2AmpPixelFunc

static CPLErr dB2PowPixelFunc(void **papoSources, int nSources, void *pData,
                              int nXSize, int nYSize, GDALDataType eSrcType,
                              GDALDataType eBufType, int nPixelSpace,
                              int nLineSpace)
{
    return ExpPixelFuncHelper(papoSources, nSources, pData, nXSize, nYSize,
                              eSrcType, eBufType, nPixelSpace, nLineSpace, 10.0,
                              1. / 10);
}  // dB2PowPixelFunc

static const char pszPowPixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument name='power' description='Exponent' type='double' "
    "mandatory='1' />"
    "</PixelFunctionArgumentsList>";

static CPLErr PowPixelFunc(void **papoSources, int nSources, void *pData,
                           int nXSize, int nYSize, GDALDataType eSrcType,
                           GDALDataType eBufType, int nPixelSpace,
                           int nLineSpace, CSLConstList papszArgs)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;
    if (GDALDataTypeIsComplex(eSrcType))
        return CE_Failure;

    double power;
    if (FetchDoubleArg(papszArgs, "power", &power) != CE_None)
        return CE_Failure;

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            const double dfPixVal =
                std::pow(GetSrcVal(papoSources[0], eSrcType, ii), power);

            GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}

// Given nt intervals spaced by dt and beginning at t0, return the index of
// the lower bound of the interval that should be used to
// interpolate/extrapolate a value for t.
static std::size_t intervalLeft(double t0, double dt, std::size_t nt, double t)
{
    if (t < t0)
    {
        return 0;
    }

    std::size_t n = static_cast<std::size_t>((t - t0) / dt);

    if (n >= nt - 1)
    {
        return nt - 2;
    }

    return n;
}

static double InterpolateLinear(double dfX0, double dfX1, double dfY0,
                                double dfY1, double dfX)
{
    return dfY0 + (dfX - dfX0) * (dfY1 - dfY0) / (dfX1 - dfX0);
}

static double InterpolateExponential(double dfX0, double dfX1, double dfY0,
                                     double dfY1, double dfX)
{
    const double r = std::log(dfY1 / dfY0) / (dfX1 - dfX0);
    return dfY0 * std::exp(r * (dfX - dfX0));
}

static const char pszInterpolatePixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument name='t0' description='t0' type='double' mandatory='1' />"
    "   <Argument name='dt' description='dt' type='double' mandatory='1' />"
    "   <Argument name='t' description='t' type='double' mandatory='1' />"
    "</PixelFunctionArgumentsList>";

template <decltype(InterpolateLinear) InterpolationFunction>
CPLErr InterpolatePixelFunc(void **papoSources, int nSources, void *pData,
                            int nXSize, int nYSize, GDALDataType eSrcType,
                            GDALDataType eBufType, int nPixelSpace,
                            int nLineSpace, CSLConstList papszArgs)
{
    /* ---- Init ---- */
    if (GDALDataTypeIsComplex(eSrcType))
        return CE_Failure;

    double dfT0;
    if (FetchDoubleArg(papszArgs, "t0", &dfT0) == CE_Failure)
        return CE_Failure;

    double dfT;
    if (FetchDoubleArg(papszArgs, "t", &dfT) == CE_Failure)
        return CE_Failure;

    double dfDt;
    if (FetchDoubleArg(papszArgs, "dt", &dfDt) == CE_Failure)
        return CE_Failure;

    if (nSources < 2)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "At least two sources required for interpolation.");
        return CE_Failure;
    }

    if (dfT == 0 || !std::isfinite(dfT))
    {
        CPLError(CE_Failure, CPLE_AppDefined, "dt must be finite and non-zero");
        return CE_Failure;
    }

    const auto i0 = intervalLeft(dfT0, dfDt, nSources, dfT);
    const auto i1 = i0 + 1;
    dfT0 = dfT0 + static_cast<double>(i0) * dfDt;
    double dfX1 = dfT0 + dfDt;

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            const double dfY0 = GetSrcVal(papoSources[i0], eSrcType, ii);
            const double dfY1 = GetSrcVal(papoSources[i1], eSrcType, ii);

            const double dfPixVal =
                InterpolationFunction(dfT0, dfX1, dfY0, dfY1, dfT);

            GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}

static const char pszReplaceNoDataPixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument type='builtin' value='NoData' />"
    "   <Argument name='to' type='double' description='New NoData value to be "
    "replaced' default='nan' />"
    "</PixelFunctionArgumentsList>";

static CPLErr ReplaceNoDataPixelFunc(void **papoSources, int nSources,
                                     void *pData, int nXSize, int nYSize,
                                     GDALDataType eSrcType,
                                     GDALDataType eBufType, int nPixelSpace,
                                     int nLineSpace, CSLConstList papszArgs)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;
    if (GDALDataTypeIsComplex(eSrcType))
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "replace_nodata cannot convert complex data types");
        return CE_Failure;
    }

    double dfOldNoData, dfNewNoData = NAN;
    if (FetchDoubleArg(papszArgs, "NoData", &dfOldNoData) != CE_None)
        return CE_Failure;
    if (FetchDoubleArg(papszArgs, "to", &dfNewNoData, &dfNewNoData) != CE_None)
        return CE_Failure;

    if (!GDALDataTypeIsFloating(eBufType) && std::isnan(dfNewNoData))
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Using nan requires a floating point type output buffer");
        return CE_Failure;
    }

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            double dfPixVal = GetSrcVal(papoSources[0], eSrcType, ii);
            if (dfPixVal == dfOldNoData || std::isnan(dfPixVal))
                dfPixVal = dfNewNoData;

            GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}

static const char pszScalePixelFuncMetadata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument type='builtin' value='offset' />"
    "   <Argument type='builtin' value='scale' />"
    "</PixelFunctionArgumentsList>";

static CPLErr ScalePixelFunc(void **papoSources, int nSources, void *pData,
                             int nXSize, int nYSize, GDALDataType eSrcType,
                             GDALDataType eBufType, int nPixelSpace,
                             int nLineSpace, CSLConstList papszArgs)
{
    /* ---- Init ---- */
    if (nSources != 1)
        return CE_Failure;
    if (GDALDataTypeIsComplex(eSrcType))
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "scale cannot by applied to complex data types");
        return CE_Failure;
    }

    double dfScale, dfOffset;
    if (FetchDoubleArg(papszArgs, "scale", &dfScale) != CE_None)
        return CE_Failure;
    if (FetchDoubleArg(papszArgs, "offset", &dfOffset) != CE_None)
        return CE_Failure;

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            const double dfPixVal =
                GetSrcVal(papoSources[0], eSrcType, ii) * dfScale + dfOffset;

            GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}

static CPLErr NormDiffPixelFunc(void **papoSources, int nSources, void *pData,
                                int nXSize, int nYSize, GDALDataType eSrcType,
                                GDALDataType eBufType, int nPixelSpace,
                                int nLineSpace)
{
    /* ---- Init ---- */
    if (nSources != 2)
        return CE_Failure;

    if (GDALDataTypeIsComplex(eSrcType))
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "norm_diff cannot by applied to complex data types");
        return CE_Failure;
    }

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            const double dfLeftVal = GetSrcVal(papoSources[0], eSrcType, ii);
            const double dfRightVal = GetSrcVal(papoSources[1], eSrcType, ii);

            const double dfDenom = (dfLeftVal + dfRightVal);

            const double dfPixVal =
                dfDenom == 0 ? std::numeric_limits<double>::infinity()
                             : (dfLeftVal - dfRightVal) / dfDenom;

            GDALCopyWords(&dfPixVal, GDT_Float64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
}  // NormDiffPixelFunc

/************************************************************************/
/*                   pszMinMaxFuncMetadataNodata                        */
/************************************************************************/

static const char pszMinMaxFuncMetadataNodata[] =
    "<PixelFunctionArgumentsList>"
    "   <Argument type='builtin' value='NoData' optional='true' />"
    "   <Argument name='propagateNoData' description='Whether the output value "
    "should be NoData as as soon as one source is NoData' type='boolean' "
    "default='false' />"
    "</PixelFunctionArgumentsList>";

template <class Comparator>
static CPLErr MinOrMaxPixelFunc(void **papoSources, int nSources, void *pData,
                                int nXSize, int nYSize, GDALDataType eSrcType,
                                GDALDataType eBufType, int nPixelSpace,
                                int nLineSpace, CSLConstList papszArgs)
{
    /* ---- Init ---- */
    if (nSources < 2)
        return CE_Failure;

    if (GDALDataTypeIsComplex(eSrcType))
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Complex data type not supported for min/max().");
        return CE_Failure;
    }

    double dfNoData = std::numeric_limits<double>::quiet_NaN();
    if (FetchDoubleArg(papszArgs, "NoData", &dfNoData, &dfNoData) != CE_None)
        return CE_Failure;
    const bool bPropagateNoData = CPLTestBool(
        CSLFetchNameValueDef(papszArgs, "propagateNoData", "false"));

    /* ---- Set pixels ---- */
    size_t ii = 0;
    for (int iLine = 0; iLine < nYSize; ++iLine)
    {
        for (int iCol = 0; iCol < nXSize; ++iCol, ++ii)
        {
            double dfRes = std::numeric_limits<double>::quiet_NaN();

            for (int iSrc = 0; iSrc < nSources; ++iSrc)
            {
                const double dfVal = GetSrcVal(papoSources[iSrc], eSrcType, ii);

                if (std::isnan(dfVal) || dfVal == dfNoData)
                {
                    if (bPropagateNoData)
                    {
                        dfRes = dfNoData;
                        break;
                    }
                }
                else if (Comparator::compare(dfVal, dfRes))
                {
                    dfRes = dfVal;
                }
            }

            if (!bPropagateNoData && std::isnan(dfRes))
            {
                dfRes = dfNoData;
            }

            GDALCopyWords(&dfRes, GDT_Float64, 0,
                          static_cast<GByte *>(pData) +
                              static_cast<GSpacing>(nLineSpace) * iLine +
                              iCol * nPixelSpace,
                          eBufType, nPixelSpace, 1);
        }
    }

    /* ---- Return success ---- */
    return CE_None;
} /* MinOrMaxPixelFunc */

static CPLErr MinPixelFunc(void **papoSources, int nSources, void *pData,
                           int nXSize, int nYSize, GDALDataType eSrcType,
                           GDALDataType eBufType, int nPixelSpace,
                           int nLineSpace, CSLConstList papszArgs)
{
    struct Comparator
    {
        static bool compare(double x, double resVal)
        {
            // Written this way to deal with resVal being NaN
            return !(x >= resVal);
        }
    };
    return MinOrMaxPixelFunc<Comparator>(papoSources, nSources, pData, nXSize,
                                         nYSize, eSrcType, eBufType,
                                         nPixelSpace, nLineSpace, papszArgs);
}

static CPLErr MaxPixelFunc(void **papoSources, int nSources, void *pData,
                           int nXSize, int nYSize, GDALDataType eSrcType,
                           GDALDataType eBufType, int nPixelSpace,
                           int nLineSpace, CSLConstList papszArgs)
{
    struct Comparator
    {
        static bool compare(double x, double resVal)
        {
            // Written this way to deal with resVal being NaN
            return !(x <= resVal);
        }
    };
    return MinOrMaxPixelFunc<Comparator>(papoSources, nSources, pData, nXSize,
                                         nYSize, eSrcType, eBufType,
                                         nPixelSpace, nLineSpace, papszArgs);
}

/************************************************************************/
/*                     GDALRegisterDefaultPixelFunc()                   */
/************************************************************************/

/**
 * This adds a default set of pixel functions to the global list of
 * available pixel functions for derived bands:
 *
 * - "real": extract real part from a single raster band (just a copy if the
 *           input is non-complex)
 * - "imag": extract imaginary part from a single raster band (0 for
 *           non-complex)
 * - "complex": make a complex band merging two bands used as real and
 *              imag values
 * - "polar": make a complex band using input bands for amplitude and
 *            phase values (b1 * exp( j * b2 ))
 * - "mod": extract module from a single raster band (real or complex)
 * - "phase": extract phase from a single raster band [-PI,PI] (0 or PI for
              non-complex)
 * - "conj": computes the complex conjugate of a single raster band (just a
 *           copy if the input is non-complex)
 * - "sum": sum 2 or more raster bands
 * - "diff": computes the difference between 2 raster bands (b1 - b2)
 * - "mul": multiply 2 or more raster bands
 * - "div": divide one raster band by another (b1 / b2).
 * - "min": minimum value of 2 or more raster bands
 * - "max": maximum value of 2 or more raster bands
 * - "norm_diff": computes the normalized difference between two raster bands:
 *                ``(b1 - b2)/(b1 + b2)``.
 * - "cmul": multiply the first band for the complex conjugate of the second
 * - "inv": inverse (1./x).
 * - "intensity": computes the intensity Re(x*conj(x)) of a single raster band
 *                (real or complex)
 * - "sqrt": perform the square root of a single raster band (real only)
 * - "log10": compute the logarithm (base 10) of the abs of a single raster
 *            band (real or complex): log10( abs( x ) )
 * - "dB": perform conversion to dB of the abs of a single raster
 *         band (real or complex): 20. * log10( abs( x ) ).
 *         Note: the optional fact parameter can be set to 10. to get the
 *         alternative formula: 10. * log10( abs( x ) )
 * - "exp": computes the exponential of each element in the input band ``x``
 *          (of real values): ``e ^ x``.
 *          The function also accepts two optional parameters: ``base`` and
 ``fact``
 *          that allow to compute the generalized formula: ``base ^ ( fact *
 x)``.
 *          Note: this function is the recommended one to perform conversion
 *          form logarithmic scale (dB): `` 10. ^ (x / 20.)``, in this case
 *          ``base = 10.`` and ``fact = 1./20``
 * - "dB2amp": perform scale conversion from logarithmic to linear
 *             (amplitude) (i.e. 10 ^ ( x / 20 ) ) of a single raster
 *             band (real only).
 *             Deprecated in GDAL v3.5. Please use the ``exp`` pixel function
 with
 *             ``base = 10.`` and ``fact = 0.05`` i.e. ``1./20``
 * - "dB2pow": perform scale conversion from logarithmic to linear
 *             (power) (i.e. 10 ^ ( x / 10 ) ) of a single raster
 *             band (real only)
 *             Deprecated in GDAL v3.5. Please use the ``exp`` pixel function
 with
 *             ``base = 10.`` and ``fact = 0.1`` i.e. ``1./10``
 * - "pow": raise a single raster band to a constant power
 * - "interpolate_linear": interpolate values between two raster bands
 *                         using linear interpolation
 * - "interpolate_exp": interpolate values between two raster bands using
 *                      exponential interpolation
 * - "scale": Apply the RasterBand metadata values of "offset" and "scale"
 * - "nan": Convert incoming NoData values to IEEE 754 nan
 *
 * @see GDALAddDerivedBandPixelFunc
 *
 * @return CE_None
 */
CPLErr GDALRegisterDefaultPixelFunc()
{
    GDALAddDerivedBandPixelFunc("real", RealPixelFunc);
    GDALAddDerivedBandPixelFunc("imag", ImagPixelFunc);
    GDALAddDerivedBandPixelFunc("complex", ComplexPixelFunc);
    GDALAddDerivedBandPixelFuncWithArgs("polar", PolarPixelFunc,
                                        pszPolarPixelFuncMetadata);
    GDALAddDerivedBandPixelFunc("mod", ModulePixelFunc);
    GDALAddDerivedBandPixelFunc("phase", PhasePixelFunc);
    GDALAddDerivedBandPixelFunc("conj", ConjPixelFunc);
    GDALAddDerivedBandPixelFuncWithArgs("sum", SumPixelFunc,
                                        pszSumPixelFuncMetadata);
    GDALAddDerivedBandPixelFunc("diff", DiffPixelFunc);
    GDALAddDerivedBandPixelFuncWithArgs("mul", MulPixelFunc,
                                        pszMulPixelFuncMetadata);
    GDALAddDerivedBandPixelFunc("div", DivPixelFunc);
    GDALAddDerivedBandPixelFunc("cmul", CMulPixelFunc);
    GDALAddDerivedBandPixelFuncWithArgs("inv", InvPixelFunc,
                                        pszInvPixelFuncMetadata);
    GDALAddDerivedBandPixelFunc("intensity", IntensityPixelFunc);
    GDALAddDerivedBandPixelFunc("sqrt", SqrtPixelFunc);
    GDALAddDerivedBandPixelFunc("log10", Log10PixelFunc);
    GDALAddDerivedBandPixelFuncWithArgs("dB", DBPixelFunc,
                                        pszDBPixelFuncMetadata);
    GDALAddDerivedBandPixelFuncWithArgs("exp", ExpPixelFunc,
                                        pszExpPixelFuncMetadata);
    GDALAddDerivedBandPixelFunc("dB2amp",
                                dB2AmpPixelFunc);  // deprecated in v3.5
    GDALAddDerivedBandPixelFunc("dB2pow",
                                dB2PowPixelFunc);  // deprecated in v3.5
    GDALAddDerivedBandPixelFuncWithArgs("pow", PowPixelFunc,
                                        pszPowPixelFuncMetadata);
    GDALAddDerivedBandPixelFuncWithArgs("interpolate_linear",
                                        InterpolatePixelFunc<InterpolateLinear>,
                                        pszInterpolatePixelFuncMetadata);
    GDALAddDerivedBandPixelFuncWithArgs(
        "interpolate_exp", InterpolatePixelFunc<InterpolateExponential>,
        pszInterpolatePixelFuncMetadata);
    GDALAddDerivedBandPixelFuncWithArgs("replace_nodata",
                                        ReplaceNoDataPixelFunc,
                                        pszReplaceNoDataPixelFuncMetadata);
    GDALAddDerivedBandPixelFuncWithArgs("scale", ScalePixelFunc,
                                        pszScalePixelFuncMetadata);
    GDALAddDerivedBandPixelFunc("norm_diff", NormDiffPixelFunc);
    GDALAddDerivedBandPixelFuncWithArgs("min", MinPixelFunc,
                                        pszMinMaxFuncMetadataNodata);
    GDALAddDerivedBandPixelFuncWithArgs("max", MaxPixelFunc,
                                        pszMinMaxFuncMetadataNodata);
    return CE_None;
}
