/******************************************************************************
 *
 * Project:  FITS Driver
 * Purpose:  Implement FITS raster read/write support
 * Author:   Simon Perkins, s.perkins@lanl.gov
 *
 ******************************************************************************
 * Copyright (c) 2001, Simon Perkins
 * Copyright (c) 2008-2020, Even Rouault <even dot rouault at spatialys.com>
 * Copyright (c) 2018, Chiara Marmo <chiara dot marmo at u-psud dot fr>
 *
 * 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.
 ****************************************************************************/

// So that OFF_T is 64 bits
#define _FILE_OFFSET_BITS 64

#include "cpl_string.h"
#include "gdal_frmts.h"
#include "gdal_pam.h"
#include "ogr_spatialref.h"
#include "ogrsf_frmts.h"

#include <string.h>
#include <fitsio.h>

#include <algorithm>
#include <string>
#include <cstring>
#include <set>
#include <vector>

/************************************************************************/
/* ==================================================================== */
/*                              FITSDataset                             */
/* ==================================================================== */
/************************************************************************/

class FITSRasterBand;
class FITSLayer;

class FITSDataset final : public GDALPamDataset
{

    friend class FITSRasterBand;
    friend class FITSLayer;

    fitsfile *m_hFITS = nullptr;

    int m_hduNum = 0;
    GDALDataType m_gdalDataType = GDT_Unknown;  // GDAL code for the image type
    int m_fitsDataType = 0;                     // FITS code for the image type

    bool m_isExistingFile = false;
    LONGLONG m_highestOffsetWritten = 0;  // How much of image has been written

    bool m_bNoDataChanged = false;
    bool m_bNoDataSet = false;
    double m_dfNoDataValue = -9999.0;

    bool m_bMetadataChanged = false;

    CPLStringList m_aosSubdatasets{};

    OGRSpatialReference m_oSRS{};

    double m_adfGeoTransform[6];
    bool m_bGeoTransformValid = false;

    bool m_bFITSInfoChanged = false;

    std::vector<std::unique_ptr<FITSLayer>> m_apoLayers{};

    CPLErr Init(fitsfile *hFITS, bool isExistingFile, int hduNum);

    void LoadGeoreferencing();
    void LoadFITSInfo();
    void WriteFITSInfo();
    void LoadMetadata(GDALMajorObject *poTarget);

  public:
    FITSDataset();  // Others should not call this constructor explicitly
    ~FITSDataset();

    static GDALDataset *Open(GDALOpenInfo *);
    static int Identify(GDALOpenInfo *);
    static GDALDataset *Create(const char *pszFilename, int nXSize, int nYSize,
                               int nBandsIn, GDALDataType eType,
                               char **papszParamList);
    static CPLErr Delete(const char *pszFilename);

    const OGRSpatialReference *GetSpatialRef() const override;
    CPLErr SetSpatialRef(const OGRSpatialReference *poSRS) override;
    virtual CPLErr GetGeoTransform(double *) override;
    virtual CPLErr SetGeoTransform(double *) override;
    char **GetMetadata(const char *papszDomain = nullptr) override;

    int GetLayerCount() override
    {
        return static_cast<int>(m_apoLayers.size());
    }
    OGRLayer *GetLayer(int) override;

    OGRLayer *ICreateLayer(const char *pszName,
                           const OGRSpatialReference *poSRS,
                           OGRwkbGeometryType eGType,
                           char **papszOptions) override;
    int TestCapability(const char *pszCap) override;

    bool GetRawBinaryLayout(GDALDataset::RawBinaryLayout &) override;
};

/************************************************************************/
/* ==================================================================== */
/*                            FITSRasterBand                           */
/* ==================================================================== */
/************************************************************************/

class FITSRasterBand final : public GDALPamRasterBand
{

    friend class FITSDataset;

    bool m_bHaveOffsetScale = false;
    double m_dfOffset = 0.0;
    double m_dfScale = 1.0;

  protected:
    FITSDataset *m_poFDS = nullptr;

    bool m_bNoDataSet = false;
    double m_dfNoDataValue = -9999.0;

  public:
    FITSRasterBand(FITSDataset *, int);
    virtual ~FITSRasterBand();

    virtual CPLErr IReadBlock(int, int, void *) override;
    virtual CPLErr IWriteBlock(int, int, void *) override;

    virtual double GetNoDataValue(int *) override final;
    virtual CPLErr SetNoDataValue(double) override final;
    virtual CPLErr DeleteNoDataValue() override final;

    virtual double GetOffset(int *pbSuccess = nullptr) override final;
    virtual CPLErr SetOffset(double dfNewValue) override final;
    virtual double GetScale(int *pbSuccess = nullptr) override final;
    virtual CPLErr SetScale(double dfNewValue) override final;
};

/************************************************************************/
/* ==================================================================== */
/*                              FITSLayer                               */
/* ==================================================================== */
/************************************************************************/
namespace
{
struct ColDesc
{
    std::string typechar{};
    int iCol = 0;  // numbering starting at 1
    int iBit = 0;  // numbering starting at 1
    int nRepeat = 0;
    int nItems = 1;
    double dfOffset = 0;
    double dfScale = 1;
    bool bHasNull = false;
    LONGLONG nNullValue = 0;
    int nTypeCode = 0;  // unset
};
}  // namespace

class FITSLayer final : public OGRLayer,
                        public OGRGetNextFeatureThroughRaw<FITSLayer>
{
    friend class FITSDataset;
    FITSDataset *m_poDS = nullptr;
    int m_hduNum = 0;
    OGRFeatureDefn *m_poFeatureDefn = nullptr;
    LONGLONG m_nCurRow = 1;
    LONGLONG m_nRows = 0;

    std::vector<ColDesc> m_aoColDescs;

    CPLStringList m_aosCreationOptions{};

    std::vector<int> m_anDeferredFieldsIndices{};

    OGRFeature *GetNextRawFeature();
    void SetActiveHDU();
    void RunDeferredFieldCreation(const OGRFeature *poFeature = nullptr);
    bool SetOrCreateFeature(const OGRFeature *poFeature, LONGLONG nRow);

  public:
    FITSLayer(FITSDataset *poDS, int hduNum, const char *pszExtName);
    ~FITSLayer();

    OGRFeatureDefn *GetLayerDefn() override
    {
        return m_poFeatureDefn;
    }
    void ResetReading() override;
    int TestCapability(const char *) override;
    OGRFeature *GetFeature(GIntBig) override;
    GIntBig GetFeatureCount(int bForce) override;
    OGRErr CreateField(OGRFieldDefn *poField, int bApproxOK) override;
    OGRErr ICreateFeature(OGRFeature *poFeature) override;
    OGRErr ISetFeature(OGRFeature *poFeature) override;
    OGRErr DeleteFeature(GIntBig nFID) override;

    DEFINE_GET_NEXT_FEATURE_THROUGH_RAW(FITSLayer)

    void SetCreationOptions(CSLConstList papszOptions)
    {
        m_aosCreationOptions = papszOptions;
    }
};

/************************************************************************/
/*                            FITSLayer()                               */
/************************************************************************/

FITSLayer::FITSLayer(FITSDataset *poDS, int hduNum, const char *pszExtName)
    : m_poDS(poDS), m_hduNum(hduNum)
{
    if (pszExtName[0] != 0)
        m_poFeatureDefn = new OGRFeatureDefn(pszExtName);
    else
        m_poFeatureDefn =
            new OGRFeatureDefn(CPLSPrintf("Table HDU %d", hduNum));
    m_poFeatureDefn->Reference();
    m_poFeatureDefn->SetGeomType(wkbNone);
    SetDescription(m_poFeatureDefn->GetName());

    SetActiveHDU();

    m_poDS->LoadMetadata(this);

    int status = 0;
    fits_get_num_rowsll(m_poDS->m_hFITS, &m_nRows, &status);
    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined, "fits_get_num_rowsll() failed");
    }
    int nCols = 0;
    status = 0;
    fits_get_num_cols(m_poDS->m_hFITS, &nCols, &status);
    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined, "fits_get_num_cols() failed");
    }

    std::vector<std::string> aosNames(nCols);
    std::vector<char *> apszNames(nCols);
    for (int i = 0; i < nCols; i++)
    {
        aosNames[i].resize(80);
        apszNames[i] = &aosNames[i][0];
    }

    status = 0;
    fits_read_btblhdrll(m_poDS->m_hFITS, nCols, nullptr, nullptr,
                        apszNames.data(), nullptr, nullptr, nullptr, nullptr,
                        &status);
    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined, "fits_read_btblhdrll() failed");
    }

    for (int i = 0; i < nCols; i++)
    {
        aosNames[i].resize(strlen(aosNames[i].c_str()));

        char typechar[80];
        LONGLONG nRepeat = 0;
        double dfScale = 0;
        double dfOffset = 0;
        status = 0;
        fits_get_bcolparmsll(m_poDS->m_hFITS, i + 1,
                             nullptr,  // column name
                             nullptr,  // unit
                             typechar, &nRepeat, &dfScale, &dfOffset,
                             nullptr,  // nulval
                             nullptr,  // tdisp
                             &status);
        if (status)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "fits_get_bcolparmsll() failed");
        }

        ColDesc oCol;

        status = 0;
        fits_read_key(m_poDS->m_hFITS, TLONGLONG, CPLSPrintf("TNULL%d", i + 1),
                      &oCol.nNullValue, nullptr, &status);
        oCol.bHasNull = status == 0;

        OGRFieldType eType = OFTString;
        OGRFieldSubType eSubType = OFSTNone;
        if (typechar[0] == 'L')  // Logical
        {
            eType = OFTInteger;
            eSubType = OFSTBoolean;
        }
        else if (typechar[0] == 'X')  // Bit array
        {
            if (nRepeat > 128)
            {
                CPLDebug("FITS", "Too large repetition count for column %s",
                         aosNames[i].c_str());
                continue;
            }
            for (int j = 1; j <= nRepeat; j++)
            {
                OGRFieldDefn oFieldDefn(
                    (aosNames[i] + CPLSPrintf("_bit%d", j)).c_str(),
                    OFTInteger);
                // cppcheck-suppress danglingTemporaryLifetime
                m_poFeatureDefn->AddFieldDefn(&oFieldDefn);

                ColDesc oColBit;
                oColBit.typechar = typechar;
                oColBit.iCol = i + 1;
                oColBit.iBit = j;
                m_aoColDescs.emplace_back(oColBit);
            }
            continue;
        }
        else if (typechar[0] == 'B')  // Unsigned byte
        {
            if (dfOffset == -128 && dfScale == 1)
            {
                eType = OFTInteger;  // signed byte
                oCol.nTypeCode = TSBYTE;
                // fits_read_col() automatically offsets numeric values
                dfOffset = 0;
            }
            else if (dfOffset != 0 || dfScale != 1)
                eType = OFTReal;
            else
                eType = OFTInteger;
        }
        else if (typechar[0] == 'I')  // 16-bit signed integer
        {
            if (dfOffset == 32768.0 && dfScale == 1)
            {
                eType = OFTInteger;  // unsigned 16-bit integer
                oCol.nTypeCode = TUSHORT;
                // fits_read_col() automatically offsets numeric values
                dfOffset = 0;
            }
            else if (dfOffset != 0 || dfScale != 1)
                eType = OFTReal;
            else
            {
                eType = OFTInteger;
                eSubType = OFSTInt16;
            }
        }
        else if (typechar[0] == 'J')  // 32-bit signed integer
        {
            if (dfOffset == 2147483648.0 && dfScale == 1)
            {
                eType = OFTInteger64;  // unsigned 32-bit integer --> needs to
                                       // promote to 64 bits
                oCol.nTypeCode = TUINT;
                // fits_read_col() automatically offsets numeric values
                dfOffset = 0;
            }
            else if (dfOffset != 0 || dfScale != 1)
                eType = OFTReal;
            else
                eType = OFTInteger;
        }
        else if (typechar[0] == 'K')  // 64-bit signed integer
        {
            if (dfOffset != 0 || dfScale != 1)
                eType = OFTReal;
            else
                eType = OFTInteger64;
        }
        else if (typechar[0] == 'A')  // Character
        {

            status = 0;
            LONGLONG nWidth = 0;
            fits_get_coltypell(m_poDS->m_hFITS, i + 1,
                               nullptr,  // typecode
                               nullptr,  // repeat
                               &nWidth, &status);
            if (status)
            {
                CPLError(CE_Failure, CPLE_AppDefined,
                         "fits_get_coltypell() failed");
            }
            if (nRepeat >= 2 * nWidth && nWidth != 0)
            {
                oCol.nItems = static_cast<int>(nRepeat / nWidth);
                eType = OFTStringList;
                nRepeat = nWidth;
            }
            else
            {
                eType = OFTString;
            }
        }
        else if (typechar[0] == 'E')  // IEEE754 32bit
        {
            eType = OFTReal;
            if (dfOffset == 0 && dfScale == 1)
                eSubType = OFSTFloat32;
            // fits_read_col() automatically scales numeric values
            dfOffset = 0;
            dfScale = 1;
        }
        else if (typechar[0] == 'D')  // IEEE754 64bit
        {
            eType = OFTReal;
            // fits_read_col() automatically scales numeric values
            dfOffset = 0;
            dfScale = 1;
        }
        else if (typechar[0] == 'C')  // IEEE754 32bit complex
        {
            eType = OFTString;
            // fits_read_col() automatically scales numeric values
            dfOffset = 0;
            dfScale = 1;
        }
        else if (typechar[0] == 'M')  // IEEE754 64bit complex
        {
            eType = OFTString;
            // fits_read_col() automatically scales numeric values
            dfOffset = 0;
            dfScale = 1;
        }
        else if (typechar[0] == 'P' || typechar[0] == 'Q')  // Array
        {
            if (typechar[1] == 'L')
            {
                nRepeat = 0;
                eType = OFTIntegerList;
                eSubType = OFSTBoolean;
            }
            else if (typechar[1] == 'B')
            {
                nRepeat = 0;
                eType = OFTIntegerList;
            }
            else if (typechar[1] == 'I')
            {
                nRepeat = 0;
                eType = OFTIntegerList;
                eSubType = OFSTInt16;
            }
            else if (typechar[1] == 'J')
            {
                nRepeat = 0;
                eType = OFTIntegerList;
            }
            else if (typechar[1] == 'K')
            {
                nRepeat = 0;
                eType = OFTInteger64List;
            }
            else if (typechar[1] == 'A')
            {
                eType = OFTString;
            }
            else if (typechar[1] == 'E')
            {
                nRepeat = 0;
                eType = OFTRealList;
                if (dfOffset == 0 && dfScale == 1)
                    eSubType = OFSTFloat32;
                // fits_read_col() automatically scales numeric values
                dfOffset = 0;
                dfScale = 1;
            }
            else if (typechar[1] == 'D')
            {
                nRepeat = 0;
                eType = OFTRealList;
                // fits_read_col() automatically scales numeric values
                dfOffset = 0;
                dfScale = 1;
            }
            else if (typechar[1] == 'C')
            {
                nRepeat = 0;
                eType = OFTStringList;
                // fits_read_col() automatically scales numeric values
                dfOffset = 0;
                dfScale = 1;
            }
            else if (typechar[1] == 'M')
            {
                nRepeat = 0;
                eType = OFTStringList;
                // fits_read_col() automatically scales numeric values
                dfOffset = 0;
                dfScale = 1;
            }
            else
            {
                CPLDebug("FITS", "Unhandled type %s", typechar);
                continue;
            }
        }
        else
        {
            CPLDebug("FITS", "Unhandled type %s", typechar);
            continue;
        }

        if (nRepeat > 1 && typechar[0] != 'A')
        {
            if (eType == OFTInteger)
                eType = OFTIntegerList;
            else if (eType == OFTInteger64)
                eType = OFTInteger64List;
            else if (eType == OFTReal)
                eType = OFTRealList;
            else if (eType == OFTString)
                eType = OFTStringList;
        }

        OGRFieldDefn oFieldDefn(aosNames[i].c_str(), eType);
        oFieldDefn.SetSubType(eSubType);
        if (typechar[0] == 'A')
            oFieldDefn.SetWidth(static_cast<int>(nRepeat));
        m_poFeatureDefn->AddFieldDefn(&oFieldDefn);

        oCol.typechar = typechar;
        oCol.iCol = i + 1;
        oCol.nRepeat = static_cast<int>(nRepeat);
        oCol.dfOffset = dfOffset;
        oCol.dfScale = dfScale;
        m_aoColDescs.emplace_back(oCol);
    }
}

/************************************************************************/
/*                           ~FITSLayer()                               */
/************************************************************************/

FITSLayer::~FITSLayer()
{
    RunDeferredFieldCreation();

    for (int i = 0; i < m_aosCreationOptions.size(); i++)
    {
        if (STARTS_WITH_CI(m_aosCreationOptions[i], "REPEAT_"))
        {
            char *pszKey = nullptr;
            CPL_IGNORE_RET_VAL(
                CPLParseNameValue(m_aosCreationOptions[i], &pszKey));
            if (pszKey &&
                m_poFeatureDefn->GetFieldIndex(pszKey + strlen("REPEAT_")) < 0)
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Creation option %s ignored as field does not exist",
                         m_aosCreationOptions[i]);
            }
            CPLFree(pszKey);
        }
    }

    m_poFeatureDefn->Release();
}

/************************************************************************/
/*                            SetActiveHDU()                            */
/************************************************************************/

void FITSLayer::SetActiveHDU()
{
    int status = 0;
    fits_movabs_hdu(m_poDS->m_hFITS, m_hduNum, nullptr, &status);
    if (status != 0)
    {
        CPLError(CE_Failure, CPLE_AppDefined, "fits_movabs_hdu() failed: %d",
                 status);
    }
}

/************************************************************************/
/*                        GetFeatureCount()                             */
/************************************************************************/

GIntBig FITSLayer::GetFeatureCount(int bForce)
{
    if (m_poAttrQuery == nullptr && m_poFilterGeom == nullptr)
        return m_nRows;
    return OGRLayer::GetFeatureCount(bForce);
}

/************************************************************************/
/*                          ResetReading()                              */
/************************************************************************/

void FITSLayer::ResetReading()
{
    m_nCurRow = 1;
}

/************************************************************************/
/*                              ReadCol                                 */
/************************************************************************/

template <typename T_FITS, typename T_GDAL, int TYPECODE> struct ReadCol
{
    static void Read(fitsfile *hFITS, const ColDesc &colDesc, int iField,
                     LONGLONG irow, OGRFeature *poFeature, int nRepeat)
    {
        int status = 0;
        std::vector<T_FITS> x(nRepeat);
        fits_read_col(hFITS, TYPECODE, colDesc.iCol, irow, 1, nRepeat, nullptr,
                      x.data(), nullptr, &status);
        if (nRepeat == 1 && colDesc.bHasNull &&
            x[0] == static_cast<T_FITS>(colDesc.nNullValue))
        {
            poFeature->SetFieldNull(iField);
        }
        else if (colDesc.dfScale != 1.0 || colDesc.dfOffset != 0.0)
        {
            std::vector<double> scaled;
            scaled.reserve(nRepeat);
            for (int i = 0; i < nRepeat; ++i)
            {
                scaled.push_back(static_cast<double>(x[i]) * colDesc.dfScale +
                                 colDesc.dfOffset);
            }
            poFeature->SetField(iField, nRepeat, scaled.data());
        }
        else if (nRepeat == 1)
        {
            poFeature->SetField(iField, static_cast<T_GDAL>(x[0]));
        }
        else
        {
            std::vector<T_GDAL> xGDAL;
            xGDAL.reserve(nRepeat);
            for (int i = 0; i < nRepeat; i++)
                xGDAL.push_back(x[i]);
            poFeature->SetField(iField, nRepeat, xGDAL.data());
        }
    }
};

/************************************************************************/
/*                        GetNextRawFeature()                           */
/************************************************************************/

OGRFeature *FITSLayer::GetNextRawFeature()
{
    auto poFeature = GetFeature(m_nCurRow);
    if (poFeature)
        m_nCurRow++;
    return poFeature;
}

/************************************************************************/
/*                           GetFeature()                               */
/************************************************************************/

OGRFeature *FITSLayer::GetFeature(GIntBig nFID)
{
    LONGLONG nRow = static_cast<LONGLONG>(nFID);
    if (nRow <= 0 || nRow > m_nRows)
        return nullptr;

    RunDeferredFieldCreation();

    OGRFeature *poFeature = new OGRFeature(m_poFeatureDefn);

    SetActiveHDU();

    const auto ReadField = [this, &poFeature, nRow](const ColDesc &colDesc,
                                                    int iField, char typechar,
                                                    int nRepeat)
    {
        int status = 0;
        if (typechar == 'L')
        {
            std::vector<char> x(nRepeat);
            fits_read_col(m_poDS->m_hFITS, TLOGICAL, colDesc.iCol, nRow, 1,
                          nRepeat, nullptr, x.data(), nullptr, &status);
            if (nRepeat == 1)
            {
                poFeature->SetField(iField, x[0] == '1' ? 1 : 0);
            }
            else
            {
                std::vector<int> intValues;
                intValues.reserve(nRepeat);
                for (int i = 0; i < nRepeat; ++i)
                {
                    intValues.push_back(x[i] == '1' ? 1 : 0);
                }
                poFeature->SetField(iField, nRepeat, intValues.data());
            }
        }
        else if (typechar == 'X')
        {
            char x = 0;
            fits_read_col_bit(m_poDS->m_hFITS, colDesc.iCol, nRow, colDesc.iBit,
                              1, &x, &status);
            poFeature->SetField(iField, x);
        }
        else if (typechar == 'B')
        {
            if (colDesc.nTypeCode == TSBYTE)
            {
                ReadCol<signed char, int, TSBYTE>::Read(
                    m_poDS->m_hFITS, colDesc, iField, nRow, poFeature, nRepeat);
            }
            else
            {
                ReadCol<GByte, int, TBYTE>::Read(
                    m_poDS->m_hFITS, colDesc, iField, nRow, poFeature, nRepeat);
            }
        }
        else if (typechar == 'I')
        {
            if (colDesc.nTypeCode == TUSHORT)
            {
                ReadCol<GUInt16, int, TUSHORT>::Read(
                    m_poDS->m_hFITS, colDesc, iField, nRow, poFeature, nRepeat);
            }
            else
            {
                ReadCol<GInt16, int, TSHORT>::Read(
                    m_poDS->m_hFITS, colDesc, iField, nRow, poFeature, nRepeat);
            }
        }
        else if (typechar == 'J')
        {
            if (colDesc.nTypeCode == TUINT)
            {
                ReadCol<GUInt32, GIntBig, TUINT>::Read(
                    m_poDS->m_hFITS, colDesc, iField, nRow, poFeature, nRepeat);
            }
            else
            {
                ReadCol<GInt32, int, TINT>::Read(
                    m_poDS->m_hFITS, colDesc, iField, nRow, poFeature, nRepeat);
            }
        }
        else if (typechar == 'K')
        {
            ReadCol<GInt64, GIntBig, TLONGLONG>::Read(
                m_poDS->m_hFITS, colDesc, iField, nRow, poFeature, nRepeat);
        }
        else if (typechar == 'A')  // Character
        {
            if (colDesc.nItems > 1)
            {
                CPLStringList aosList;
                for (int iItem = 1; iItem <= colDesc.nItems; iItem++)
                {
                    std::string osStr;
                    if (nRepeat)
                    {
                        osStr.resize(nRepeat);
                        char *pszStr = &osStr[0];
                        fits_read_col_str(m_poDS->m_hFITS, colDesc.iCol, nRow,
                                          iItem, 1, nullptr, &pszStr, nullptr,
                                          &status);
                    }
                    aosList.AddString(osStr.c_str());
                }
                poFeature->SetField(iField, aosList.List());
            }
            else
            {
                std::string osStr;
                if (nRepeat)
                {
                    osStr.resize(nRepeat);
                    char *pszStr = &osStr[0];
                    fits_read_col_str(m_poDS->m_hFITS, colDesc.iCol, nRow, 1, 1,
                                      nullptr, &pszStr, nullptr, &status);
                }
                poFeature->SetField(iField, osStr.c_str());
            }
        }
        else if (typechar == 'E')  // IEEE754 32bit
        {
            ReadCol<float, double, TFLOAT>::Read(
                m_poDS->m_hFITS, colDesc, iField, nRow, poFeature, nRepeat);
        }
        else if (typechar == 'D')  // IEEE754 64bit
        {
            std::vector<double> x(nRepeat);
            fits_read_col(m_poDS->m_hFITS, TDOUBLE, colDesc.iCol, nRow, 1,
                          nRepeat, nullptr, x.data(), nullptr, &status);
            if (nRepeat == 1)
                poFeature->SetField(iField, x[0]);
            else
                poFeature->SetField(iField, nRepeat, x.data());
        }
        else if (typechar == 'C')  // IEEE754 32bit complex
        {
            std::vector<float> x(2 * nRepeat);
            fits_read_col(m_poDS->m_hFITS, TCOMPLEX, colDesc.iCol, nRow, 1,
                          nRepeat, nullptr, x.data(), nullptr, &status);
            CPLStringList aosList;
            for (int i = 0; i < nRepeat; ++i)
                aosList.AddString(
                    CPLSPrintf("%.18g + %.18gj", x[2 * i + 0], x[2 * i + 1]));
            if (nRepeat == 1)
                poFeature->SetField(iField, aosList[0]);
            else
                poFeature->SetField(iField, aosList.List());
        }
        else if (typechar == 'M')  // IEEE754 64bit complex
        {
            std::vector<double> x(2 * nRepeat);
            fits_read_col(m_poDS->m_hFITS, TDBLCOMPLEX, colDesc.iCol, nRow, 1,
                          nRepeat, nullptr, x.data(), nullptr, &status);
            CPLStringList aosList;
            for (int i = 0; i < nRepeat; ++i)
            {
                aosList.AddString(
                    CPLSPrintf("%.18g + %.18gj", x[2 * i + 0], x[2 * i + 1]));
            }
            if (nRepeat == 1)
                poFeature->SetField(iField, aosList[0]);
            else
                poFeature->SetField(iField, aosList.List());
        }
        else
        {
            CPLDebug("FITS", "Unhandled typechar %c", typechar);
        }
        if (status)
        {
            CPLError(CE_Failure, CPLE_AppDefined, "fits_read_col() failed");
        }
    };

    const int nFieldCount = poFeature->GetFieldCount();
    for (int iField = 0; iField < nFieldCount; iField++)
    {
        const auto &colDesc = m_aoColDescs[iField];
        if (colDesc.typechar[0] == 'P' || colDesc.typechar[0] == 'Q')
        {
            int status = 0;
            LONGLONG nRepeat = 0;
            fits_read_descriptll(m_poDS->m_hFITS, colDesc.iCol, nRow, &nRepeat,
                                 nullptr, &status);
            ReadField(colDesc, iField, colDesc.typechar[1],
                      static_cast<int>(nRepeat));
        }
        else
        {
            ReadField(colDesc, iField, colDesc.typechar[0], colDesc.nRepeat);
        }
    }
    poFeature->SetFID(nRow);
    return poFeature;
}

/************************************************************************/
/*                         TestCapability()                             */
/************************************************************************/

int FITSLayer::TestCapability(const char *pszCap)
{
    if (EQUAL(pszCap, OLCFastFeatureCount))
        return m_poAttrQuery == nullptr && m_poFilterGeom == nullptr;

    if (EQUAL(pszCap, OLCRandomRead))
        return true;

    if (EQUAL(pszCap, OLCCreateField) || EQUAL(pszCap, OLCSequentialWrite) ||
        EQUAL(pszCap, OLCRandomWrite) || EQUAL(pszCap, OLCDeleteFeature))
    {
        return m_poDS->GetAccess() == GA_Update;
    }

    return false;
}

/************************************************************************/
/*                        RunDeferredFieldCreation()                    */
/************************************************************************/

void FITSLayer::RunDeferredFieldCreation(const OGRFeature *poFeature)
{
    if (m_anDeferredFieldsIndices.empty())
        return;

    SetActiveHDU();

    CPLString osPendingBitFieldName{};
    int nPendingBitFieldSize = 0;
    std::set<CPLString> oSetBitFieldNames{};

    const auto FlushCreationPendingBitField = [this, &osPendingBitFieldName,
                                               &nPendingBitFieldSize,
                                               &oSetBitFieldNames]()
    {
        if (osPendingBitFieldName.empty())
            return;

        const int iCol =
            m_aoColDescs.empty() ? 1 : m_aoColDescs.back().iCol + 1;
        for (int iBit = 1; iBit <= nPendingBitFieldSize; iBit++)
        {
            ColDesc oCol;
            oCol.iCol = iCol;
            oCol.iBit = iBit;
            oCol.typechar = 'X';
            m_aoColDescs.emplace_back(oCol);
        }

        int status = 0;
        CPLString osTForm;
        osTForm.Printf("%dX", nPendingBitFieldSize);
        fits_insert_col(m_poDS->m_hFITS, iCol, &osPendingBitFieldName[0],
                        &osTForm[0], &status);
        if (status != 0)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "fits_insert_col() failed: %d", status);
        }

        oSetBitFieldNames.insert(osPendingBitFieldName);
        osPendingBitFieldName.clear();
        nPendingBitFieldSize = 0;
    };

    const bool bRepeatFromFirstFeature =
        poFeature != nullptr &&
        EQUAL(m_aosCreationOptions.FetchNameValueDef("COMPUTE_REPEAT",
                                                     "AT_FIELD_CREATION"),
              "AT_FIRST_FEATURE_CREATION");

    char **papszMD = GetMetadata();
    bool bFirstMD = true;

    std::map<CPLString, std::map<CPLString, CPLString>> oMapColNameToMetadata;

    // Remap column related metadata (likely coming from source FITS) to
    // actual column numbers
    std::map<int, CPLString> oMapFITSMDColToName;
    for (auto papszIter = papszMD; papszIter && *papszIter; ++papszIter)
    {
        char *pszKey = nullptr;
        const char *pszValue = CPLParseNameValue(*papszIter, &pszKey);
        if (pszKey && pszValue)
        {
            bool bIgnore = false;
            for (const char *pszPrefix :
                 {"TTYPE", "TFORM", "TUNIT", "TNULL", "TSCAL", "TZERO", "TDISP",
                  "TDIM", "TBCOL", "TCTYP", "TCUNI", "TCRPX", "TCRVL", "TCDLT",
                  "TRPOS"})
            {
                if (STARTS_WITH(pszKey, pszPrefix))
                {
                    const char *pszCol = pszKey + strlen(pszPrefix);
                    const int nCol = atoi(pszCol);
                    if (!EQUAL(pszPrefix, "TTYPE"))
                    {
                        auto oIter = oMapFITSMDColToName.find(nCol);
                        CPLString osColName;
                        if (oIter == oMapFITSMDColToName.end())
                        {
                            const char *pszColName = CSLFetchNameValue(
                                papszMD,
                                (std::string("TTYPE") + pszCol).c_str());
                            if (pszColName)
                            {
                                osColName = pszColName;
                                osColName.Trim();
                                oMapFITSMDColToName[nCol] = osColName;
                            }
                        }
                        else
                        {
                            osColName = oIter->second;
                        }
                        if (!osColName.empty())
                        {
                            oMapColNameToMetadata[osColName][pszPrefix] =
                                CPLString(pszValue).Trim();
                        }
                    }
                    bIgnore = true;
                    break;
                }
            }

            if (!bIgnore && strlen(pszKey) <= 8 && !EQUAL(pszKey, "TFIELDS") &&
                !EQUAL(pszKey, "EXTNAME"))
            {
                if (bFirstMD)
                {
                    int status = 0;
                    fits_write_key_longwarn(m_poDS->m_hFITS, &status);
                    bFirstMD = false;
                }

                char *pszValueNonConst = const_cast<char *>(pszValue);
                int status = 0;
                fits_update_key_longstr(m_poDS->m_hFITS, pszKey,
                                        pszValueNonConst, nullptr, &status);
            }
        }
        CPLFree(pszKey);
    }

    for (const int nFieldIdx : m_anDeferredFieldsIndices)
    {
        const auto poFieldDefn = m_poFeatureDefn->GetFieldDefn(nFieldIdx);
        const auto &oFieldDefn = *poFieldDefn;
        const char *pszFieldName = oFieldDefn.GetNameRef();
        const OGRFieldType eType = oFieldDefn.GetType();
        const OGRFieldSubType eSubType = oFieldDefn.GetSubType();

        if (eType == OFTInteger)
        {
            const char *pszBit = strstr(pszFieldName, "_bit");
            long iBit = 0;
            char *pszEndPtr = nullptr;
            if (pszBit &&
                (iBit = strtol(pszBit + strlen("_bit"), &pszEndPtr, 10)) > 0 &&
                pszEndPtr && *pszEndPtr == '\0')
            {
                CPLString osName;
                osName.assign(pszFieldName, pszBit - pszFieldName);
                if (oSetBitFieldNames.find(osName) == oSetBitFieldNames.end())
                {
                    if (!osPendingBitFieldName.empty() &&
                        osPendingBitFieldName != osName)
                    {
                        FlushCreationPendingBitField();
                    }

                    if (osPendingBitFieldName.empty())
                    {
                        osPendingBitFieldName = osName;
                        nPendingBitFieldSize = 1;
                        continue;
                    }
                    else if (iBit == nPendingBitFieldSize + 1)
                    {
                        nPendingBitFieldSize++;
                        continue;
                    }
                }
            }
        }

        FlushCreationPendingBitField();

        CPLString osTForm;
        ColDesc oCol;
        oCol.iCol = m_aoColDescs.empty() ? 1 : m_aoColDescs.back().iCol + 1;
        oCol.nRepeat = 1;

        CPLString osRepeat;
        const char *pszRepeat = m_aosCreationOptions.FetchNameValue(
            (CPLString("REPEAT_") + pszFieldName).c_str());

        const auto osTFormFromMD = oMapColNameToMetadata[pszFieldName]["TFORM"];

        // For fields of type list, determine if we can know if it has a fixed
        // number of elements
        if (eType == OFTIntegerList || eType == OFTInteger64List ||
            eType == OFTRealList)
        {
            // First take into account the REPEAT_{FIELD_NAME} creatin option
            if (pszRepeat)
            {
                osRepeat = pszRepeat;
                oCol.nRepeat = atoi(pszRepeat);
            }
            // Then if COMPUTE_REPEAT=AT_FIRST_FEATURE_CREATION was specified
            // and we have a feature, then look at the number of items in the
            // field
            else if (bRepeatFromFirstFeature &&
                     poFeature->IsFieldSetAndNotNull(nFieldIdx))
            {
                int nCount = 0;
                if (eType == OFTIntegerList)
                {
                    CPL_IGNORE_RET_VAL(
                        poFeature->GetFieldAsIntegerList(nFieldIdx, &nCount));
                }
                else if (eType == OFTInteger64List)
                {
                    CPL_IGNORE_RET_VAL(
                        poFeature->GetFieldAsInteger64List(nFieldIdx, &nCount));
                }
                else if (eType == OFTRealList)
                {
                    CPL_IGNORE_RET_VAL(
                        poFeature->GetFieldAsDoubleList(nFieldIdx, &nCount));
                }
                else
                {
                    CPLAssert(false);
                }
                osRepeat.Printf("%d", nCount);
                oCol.nRepeat = nCount;
            }
            else
            {
                if (!osTFormFromMD.empty() && osTFormFromMD[0] >= '1' &&
                    osTFormFromMD[0] <= '9')
                {
                    oCol.nRepeat = atoi(osTFormFromMD.c_str());
                    osRepeat.Printf("%d", oCol.nRepeat);
                }
                else
                {
                    oCol.nRepeat = 0;
                    oCol.typechar = 'P';
                }
            }
        }
        else if (pszRepeat)
        {
            CPLError(CE_Warning, CPLE_AppDefined,
                     "%s ignored on a non-List data type",
                     (CPLString("REPEAT_") + pszFieldName).c_str());
        }

        switch (eType)
        {
            case OFTIntegerList:
            case OFTInteger:
                if (eSubType == OFSTInt16)
                {
                    oCol.typechar += 'I';
                    oCol.nTypeCode = TSHORT;
                }
                else
                {
                    oCol.typechar += 'J';
                    oCol.nTypeCode = TINT;
                }
                break;

            case OFTInteger64List:
            case OFTInteger64:
                oCol.typechar += 'K';
                oCol.nTypeCode = TLONGLONG;
                break;

            case OFTRealList:
            case OFTReal:
                if (eSubType == OFSTFloat32)
                {
                    oCol.typechar += 'E';
                    oCol.nTypeCode = TFLOAT;
                }
                else
                {
                    oCol.typechar += 'D';
                    oCol.nTypeCode = TDOUBLE;
                }
                break;

            case OFTString:
                if (osTFormFromMD == "C")
                {
                    oCol.typechar = "C";
                    oCol.nTypeCode = TCOMPLEX;
                }
                else if (osTFormFromMD == "M")
                {
                    oCol.typechar = "M";
                    oCol.nTypeCode = TDBLCOMPLEX;
                }
                else
                {
                    if (oFieldDefn.GetWidth() == 0)
                    {
                        oCol.typechar = "PA";
                    }
                    else
                    {
                        oCol.typechar = "A";
                        oCol.nRepeat = oFieldDefn.GetWidth();
                        osTForm = CPLSPrintf("%dA", oCol.nRepeat);
                    }
                    oCol.nTypeCode = TSTRING;
                }
                break;

            default:
                CPLError(CE_Failure, CPLE_NotSupported,
                         "Unsupported field type: should not happen");
                break;
        }

        CPLString osTType(pszFieldName);
        if (osTForm.empty())
        {
            if ((eType == OFTIntegerList || eType == OFTInteger64List ||
                 eType == OFTRealList) &&
                !osRepeat.empty())
            {
                osTForm = osRepeat;
                osTForm += oCol.typechar;
            }
            else
            {
                osTForm = oCol.typechar;
            }
        }
        int status = 0;
        fits_insert_col(m_poDS->m_hFITS, oCol.iCol, &osTType[0], &osTForm[0],
                        &status);
        if (status != 0)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "fits_insert_col() failed: %d", status);
        }

        // Set unit from metadata
        auto osUnit = oMapColNameToMetadata[pszFieldName]["TUNIT"];
        if (!osUnit.empty())
        {
            CPLString osKey;
            osKey.Printf("TUNIT%d", oCol.iCol);
            fits_update_key_longstr(m_poDS->m_hFITS, osKey.data(),
                                    osUnit.data(), nullptr, &status);
        }

        m_aoColDescs.emplace_back(oCol);
    }

    m_anDeferredFieldsIndices.clear();
    CPLAssert(static_cast<int>(m_aoColDescs.size()) ==
              m_poFeatureDefn->GetFieldCount());
}

/************************************************************************/
/*                           CreateField()                              */
/************************************************************************/

OGRErr FITSLayer::CreateField(OGRFieldDefn *poField, int /* bApproxOK */)
{
    if (!TestCapability(OLCCreateField))
        return OGRERR_FAILURE;
    if (m_poFeatureDefn->GetFieldIndex(poField->GetNameRef()) >= 0)
    {
        CPLError(CE_Failure, CPLE_NotSupported,
                 "A field with name %s already exists", poField->GetNameRef());
        return OGRERR_FAILURE;
    }
    if (poField->GetType() == OFTStringList)
    {
        CPLError(CE_Failure, CPLE_NotSupported, "Unsupported field type");
        return OGRERR_FAILURE;
    }

    m_anDeferredFieldsIndices.emplace_back(m_poFeatureDefn->GetFieldCount());
    m_poFeatureDefn->AddFieldDefn(poField);
    return OGRERR_NONE;
}

/************************************************************************/
/*                              WriteCol                                */
/************************************************************************/

template <class T> static T Round(double dfValue)
{
    return static_cast<T>(floor(dfValue + 0.5));
}

template <> double Round<double>(double dfValue)
{
    return dfValue;
}

template <> float Round<float>(double dfValue)
{
    return static_cast<float>(dfValue);
}

template <typename T_FITS, typename T_GDAL, int TYPECODE,
          T_GDAL (OGRFeature::*GetFieldMethod)(int) const,
          const T_GDAL *(OGRFeature::*GetFieldListMethod)(int, int *) const>
struct WriteCol
{
    static int Write(fitsfile *hFITS, const ColDesc &colDesc, int iField,
                     LONGLONG irow, const OGRFeature *poFeature)
    {
        int status = 0;
        int nRepeat = colDesc.nRepeat;
        const auto poFieldDefn = poFeature->GetFieldDefnRef(iField);
        const auto eOGRType = poFieldDefn->GetType();
        int nCount = 0;
        // cppcheck-suppress constStatement
        const T_GDAL *panList =
            (eOGRType == OFTIntegerList || eOGRType == OFTInteger64List ||
             eOGRType == OFTRealList)
                ? (poFeature->*GetFieldListMethod)(iField, &nCount)
                : nullptr;
        if (panList)
        {
            nRepeat = nRepeat == 0 ? nCount : std::min(nRepeat, nCount);
            if (nCount > nRepeat)
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Field %s of feature " CPL_FRMT_GIB " had %d "
                         "elements, but had to be truncated to %d",
                         poFieldDefn->GetNameRef(), static_cast<GIntBig>(irow),
                         nCount, nRepeat);
            }
        }
        else
        {
            nRepeat = 1;
        }

        if (nRepeat == 0)
            return 0;

        if (colDesc.bHasNull && nRepeat == 1 && poFeature->IsFieldNull(iField))
        {
            T_FITS x = static_cast<T_FITS>(colDesc.nNullValue);
            fits_write_col(hFITS, TYPECODE, colDesc.iCol, irow, 1, nRepeat, &x,
                           &status);
        }
        else if (nRepeat == 1)
        {
            const auto val =
                panList ? panList[0] : (poFeature->*GetFieldMethod)(iField);
            if (colDesc.dfScale != 1.0 || colDesc.dfOffset != 0.0)
            {
                T_FITS x =
                    Round<T_FITS>((val - colDesc.dfOffset) / colDesc.dfScale);
                fits_write_col(hFITS, TYPECODE, colDesc.iCol, irow, 1, nRepeat,
                               &x, &status);
            }
            else
            {
                T_FITS x = static_cast<T_FITS>(val);
                fits_write_col(hFITS, TYPECODE, colDesc.iCol, irow, 1, nRepeat,
                               &x, &status);
            }
        }
        else
        {
            CPLAssert(panList);

            std::vector<T_FITS> x;
            x.reserve(nRepeat);
            if (colDesc.dfScale != 1.0 || colDesc.dfOffset != 0.0)
            {
                for (int i = 0; i < nRepeat; i++)
                {
                    x.push_back(Round<T_FITS>((panList[i] - colDesc.dfOffset) /
                                              colDesc.dfScale));
                }
                fits_write_col(hFITS, TYPECODE, colDesc.iCol, irow, 1, nRepeat,
                               x.data(), &status);
            }
            else
            {
                for (int i = 0; i < nRepeat; i++)
                {
                    x.push_back(static_cast<T_FITS>(panList[i]));
                }
                fits_write_col(hFITS, TYPECODE, colDesc.iCol, irow, 1, nRepeat,
                               x.data(), &status);
            }
        }
        return status;
    }
};

/************************************************************************/
/*                            WriteComplex                              */
/************************************************************************/

template <typename T, int TYPECODE> struct WriteComplex
{
    static int Write(fitsfile *hFITS, const ColDesc &colDesc, int iField,
                     LONGLONG irow, const OGRFeature *poFeature)
    {
        int status = 0;
        const auto poFieldDefn = poFeature->GetFieldDefnRef(iField);
        if (poFieldDefn->GetType() == OFTStringList)
        {
            auto papszStrings = poFeature->GetFieldAsStringList(iField);
            const int nCount = CSLCount(papszStrings);
            int nRepeat = colDesc.nRepeat;
            nRepeat = nRepeat == 0 ? nCount : std::min(nRepeat, nCount);
            if (nRepeat > nCount)
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Field %s of feature " CPL_FRMT_GIB " had %d "
                         "elements, but had to be truncated to %d",
                         poFieldDefn->GetNameRef(), static_cast<GIntBig>(irow),
                         nRepeat, nCount);
            }
            std::vector<T> x(2 * nRepeat);
            for (int i = 0; i < nRepeat; i++)
            {
                double re = 0;
                double im = 0;
                CPLsscanf(papszStrings[i], "%lf + %lfj", &re, &im);
                x[2 * i] = static_cast<T>(re);
                x[2 * i + 1] = static_cast<T>(im);
            }
            fits_write_col(hFITS, TYPECODE, colDesc.iCol, irow, 1, nRepeat,
                           x.data(), &status);
        }
        else
        {
            std::vector<T> x(2);
            double re = 0;
            double im = 0;
            CPLsscanf(poFeature->GetFieldAsString(iField), "%lf + %lfj", &re,
                      &im);
            x[0] = static_cast<T>(re);
            x[1] = static_cast<T>(im);
            fits_write_col(hFITS, TYPECODE, colDesc.iCol, irow, 1, 1, x.data(),
                           &status);
        }
        return status;
    }
};

/************************************************************************/
/*                        SetOrCreateFeature()                          */
/************************************************************************/

bool FITSLayer::SetOrCreateFeature(const OGRFeature *poFeature, LONGLONG nRow)
{
    SetActiveHDU();

    const auto WriteField = [this, &poFeature, nRow](int iField)
    {
        const auto poFieldDefn = poFeature->GetFieldDefnRef(iField);
        const auto &colDesc = m_aoColDescs[iField];
        const char typechar =
            (colDesc.typechar[0] == 'P' || colDesc.typechar[0] == 'Q')
                ? colDesc.typechar[1]
                : colDesc.typechar[0];
        int nRepeat = colDesc.nRepeat;
        int status = 0;
        if (typechar == 'L')
        {
            const auto ToLogical = [](int x) -> char { return x ? '1' : '0'; };

            if (poFieldDefn->GetType() == OFTIntegerList)
            {
                int nCount = 0;
                const int *panVals =
                    poFeature->GetFieldAsIntegerList(iField, &nCount);
                nRepeat = nRepeat == 0 ? nCount : std::min(nRepeat, nCount);
                if (nRepeat > nCount)
                {
                    CPLError(CE_Warning, CPLE_AppDefined,
                             "Field %s of feature " CPL_FRMT_GIB " had %d "
                             "elements, but had to be truncated to %d",
                             poFieldDefn->GetNameRef(),
                             static_cast<GIntBig>(nRow), nRepeat, nCount);
                }
                std::vector<char> x(nRepeat);
                for (int i = 0; i < nRepeat; i++)
                {
                    x[i] = ToLogical(panVals[i]);
                }
                fits_write_col(m_poDS->m_hFITS, TLOGICAL, colDesc.iCol, nRow, 1,
                               nRepeat, x.data(), &status);
            }
            else
            {
                char x = ToLogical(poFeature->GetFieldAsInteger(iField));
                fits_write_col(m_poDS->m_hFITS, TLOGICAL, colDesc.iCol, nRow, 1,
                               nRepeat, &x, &status);
            }
        }
        else if (typechar == 'X')  // bit array
        {
            char flag = poFeature->GetFieldAsInteger(iField) ? 0x80 : 0;
            fits_write_col_bit(m_poDS->m_hFITS, colDesc.iCol, nRow,
                               colDesc.iBit, 1, &flag, &status);
        }
        else if (typechar == 'B')
        {
            if (colDesc.nTypeCode == TSBYTE)
            {
                status = WriteCol<
                    signed char, int, TSBYTE, &OGRFeature::GetFieldAsInteger,
                    &OGRFeature::GetFieldAsIntegerList>::Write(m_poDS->m_hFITS,
                                                               colDesc, iField,
                                                               nRow, poFeature);
            }
            else
            {
                status = WriteCol<
                    GByte, int, TBYTE, &OGRFeature::GetFieldAsInteger,
                    &OGRFeature::GetFieldAsIntegerList>::Write(m_poDS->m_hFITS,
                                                               colDesc, iField,
                                                               nRow, poFeature);
            }
        }
        else if (typechar == 'I')
        {
            if (colDesc.nTypeCode == TUSHORT)
            {
                status = WriteCol<
                    GUInt16, int, TUSHORT, &OGRFeature::GetFieldAsInteger,
                    &OGRFeature::GetFieldAsIntegerList>::Write(m_poDS->m_hFITS,
                                                               colDesc, iField,
                                                               nRow, poFeature);
            }
            else
            {
                status = WriteCol<
                    GInt16, int, TSHORT, &OGRFeature::GetFieldAsInteger,
                    &OGRFeature::GetFieldAsIntegerList>::Write(m_poDS->m_hFITS,
                                                               colDesc, iField,
                                                               nRow, poFeature);
            }
        }
        else if (typechar == 'J')
        {
            if (colDesc.nTypeCode == TUINT)
            {
                status = WriteCol<
                    GUInt32, GIntBig, TUINT, &OGRFeature::GetFieldAsInteger64,
                    &OGRFeature::GetFieldAsInteger64List>::Write(m_poDS
                                                                     ->m_hFITS,
                                                                 colDesc,
                                                                 iField, nRow,
                                                                 poFeature);
            }
            else
            {
                status = WriteCol<
                    GInt32, int, TINT, &OGRFeature::GetFieldAsInteger,
                    &OGRFeature::GetFieldAsIntegerList>::Write(m_poDS->m_hFITS,
                                                               colDesc, iField,
                                                               nRow, poFeature);
            }
        }
        else if (typechar == 'K')
        {
            status = WriteCol<
                GInt64, GIntBig, TLONGLONG, &OGRFeature::GetFieldAsInteger64,
                &OGRFeature::GetFieldAsInteger64List>::Write(m_poDS->m_hFITS,
                                                             colDesc, iField,
                                                             nRow, poFeature);
        }
        else if (typechar == 'A')  // Character
        {
            if (poFieldDefn->GetType() == OFTStringList)
            {
                auto papszStrings = poFeature->GetFieldAsStringList(iField);
                const int nStringCount = CSLCount(papszStrings);
                const int nItems = std::min(colDesc.nItems, nStringCount);
                if (nItems > nStringCount)
                {
                    CPLError(CE_Warning, CPLE_AppDefined,
                             "Field %s of feature " CPL_FRMT_GIB " had %d "
                             "elements, but had to be truncated to %d",
                             poFieldDefn->GetNameRef(),
                             static_cast<GIntBig>(nRow), nItems, nStringCount);
                }
                fits_write_col_str(m_poDS->m_hFITS, colDesc.iCol, nRow, 1,
                                   nItems, papszStrings, &status);
            }
            else
            {
                char *pszStr =
                    const_cast<char *>(poFeature->GetFieldAsString(iField));
                fits_write_col_str(m_poDS->m_hFITS, colDesc.iCol, nRow, 1, 1,
                                   &pszStr, &status);
            }
        }
        else if (typechar == 'E')  // IEEE754 32bit
        {
            status = WriteCol<
                float, double, TFLOAT, &OGRFeature::GetFieldAsDouble,
                &OGRFeature::GetFieldAsDoubleList>::Write(m_poDS->m_hFITS,
                                                          colDesc, iField, nRow,
                                                          poFeature);
        }
        else if (typechar == 'D')  // IEEE754 64bit
        {
            status = WriteCol<
                double, double, TDOUBLE, &OGRFeature::GetFieldAsDouble,
                &OGRFeature::GetFieldAsDoubleList>::Write(m_poDS->m_hFITS,
                                                          colDesc, iField, nRow,
                                                          poFeature);
        }
        else if (typechar == 'C')  // IEEE754 32bit complex
        {
            status = WriteComplex<float, TCOMPLEX>::Write(
                m_poDS->m_hFITS, colDesc, iField, nRow, poFeature);
        }
        else if (typechar == 'M')  // IEEE754 64bit complex
        {
            status = WriteComplex<double, TDBLCOMPLEX>::Write(
                m_poDS->m_hFITS, colDesc, iField, nRow, poFeature);
        }
        else
        {
            CPLDebug("FITS", "Unhandled typechar %c", typechar);
        }
        if (status)
        {
            CPLError(CE_Failure, CPLE_AppDefined, "fits_write_col() failed");
        }
        return status == 0;
    };

    bool bOK = true;
    const int nFieldCount = poFeature->GetFieldCount();
    for (int iField = 0; iField < nFieldCount; iField++)
    {
        if (!WriteField(iField))
            bOK = false;
    }
    return bOK;
}

/************************************************************************/
/*                           ICreateFeature()                           */
/************************************************************************/

OGRErr FITSLayer::ICreateFeature(OGRFeature *poFeature)
{
    if (!TestCapability(OLCSequentialWrite))
        return OGRERR_FAILURE;

    RunDeferredFieldCreation(poFeature);

    m_nRows++;
    SetActiveHDU();
    const bool bOK = SetOrCreateFeature(poFeature, m_nRows);
    poFeature->SetFID(m_nRows);

    return bOK ? OGRERR_NONE : OGRERR_FAILURE;
}

/************************************************************************/
/*                           ISetFeature()                              */
/************************************************************************/

OGRErr FITSLayer::ISetFeature(OGRFeature *poFeature)
{
    if (!TestCapability(OLCRandomWrite))
        return OGRERR_FAILURE;

    RunDeferredFieldCreation();

    const GIntBig nRow = poFeature->GetFID();
    if (nRow <= 0 || nRow > m_nRows)
        return OGRERR_NON_EXISTING_FEATURE;

    SetActiveHDU();
    const bool bOK = SetOrCreateFeature(poFeature, nRow);
    return bOK ? OGRERR_NONE : OGRERR_FAILURE;
}

/************************************************************************/
/*                          DeleteFeature()                             */
/************************************************************************/

OGRErr FITSLayer::DeleteFeature(GIntBig nFID)
{
    if (!TestCapability(OLCDeleteFeature))
        return OGRERR_FAILURE;

    if (nFID <= 0 || nFID > m_nRows)
        return OGRERR_NON_EXISTING_FEATURE;

    SetActiveHDU();

    int status = 0;
    fits_delete_rows(m_poDS->m_hFITS, nFID, 1, &status);
    m_nRows--;
    return status == 0 ? OGRERR_NONE : OGRERR_FAILURE;
}

/************************************************************************/
/*                          FITSRasterBand()                           */
/************************************************************************/

FITSRasterBand::FITSRasterBand(FITSDataset *poDSIn, int nBandIn)
    : m_poFDS(poDSIn)
{
    poDS = poDSIn;
    nBand = nBandIn;
    eDataType = poDSIn->m_gdalDataType;
    nBlockXSize = poDSIn->nRasterXSize;
    nBlockYSize = 1;
}

/************************************************************************/
/*                          ~FITSRasterBand()                           */
/************************************************************************/

FITSRasterBand::~FITSRasterBand()
{
    FlushCache(true);
}

/************************************************************************/
/*                             IReadBlock()                             */
/************************************************************************/

CPLErr FITSRasterBand::IReadBlock(CPL_UNUSED int nBlockXOff, int nBlockYOff,
                                  void *pImage)
{
    // A FITS block is one row (we assume BSQ formatted data)
    FITSDataset *dataset = m_poFDS;
    fitsfile *hFITS = dataset->m_hFITS;
    int status = 0;

    // Since a FITS block is a whole row, nBlockXOff must be zero
    // and the row number equals the y block offset. Also, nBlockYOff
    // cannot be greater than the number of rows
    CPLAssert(nBlockXOff == 0);
    CPLAssert(nBlockYOff < nRasterYSize);

    // Calculate offsets and read in the data. Note that FITS array offsets
    // start at 1 at the bottom left...
    LONGLONG offset =
        static_cast<LONGLONG>(nBand - 1) * nRasterXSize * nRasterYSize +
        (static_cast<LONGLONG>(nRasterYSize - 1 - nBlockYOff) * nRasterXSize +
         1);
    long nElements = nRasterXSize;

    // If we haven't written this block to the file yet, then attempting
    // to read causes an error, so in this case, just return zeros.
    if (!dataset->m_isExistingFile && offset > dataset->m_highestOffsetWritten)
    {
        memset(pImage, 0,
               nBlockXSize * nBlockYSize * GDALGetDataTypeSize(eDataType) / 8);
        return CE_None;
    }

    // Otherwise read in the image data
    fits_read_img(hFITS, dataset->m_fitsDataType, offset, nElements, nullptr,
                  pImage, nullptr, &status);

    // Capture special case of non-zero status due to data range
    // overflow Standard GDAL policy is to silently truncate, which is
    // what CFITSIO does, in addition to returning NUM_OVERFLOW (412) as
    // the status.
    if (status == NUM_OVERFLOW)
        status = 0;

    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Couldn't read image data from FITS file (%d).", status);
        return CE_Failure;
    }

    return CE_None;
}

/************************************************************************/
/*                            IWriteBlock()                             */
/*                                                                      */
/************************************************************************/

CPLErr FITSRasterBand::IWriteBlock(CPL_UNUSED int nBlockXOff, int nBlockYOff,
                                   void *pImage)
{
    FITSDataset *dataset = m_poFDS;
    fitsfile *hFITS = dataset->m_hFITS;
    int status = 0;

    // Since a FITS block is a whole row, nBlockXOff must be zero
    // and the row number equals the y block offset. Also, nBlockYOff
    // cannot be greater than the number of rows

    // Calculate offsets and read in the data. Note that FITS array offsets
    // start at 1 at the bottom left...
    LONGLONG offset =
        static_cast<LONGLONG>(nBand - 1) * nRasterXSize * nRasterYSize +
        (static_cast<LONGLONG>(nRasterYSize - 1 - nBlockYOff) * nRasterXSize +
         1);
    long nElements = nRasterXSize;
    fits_write_img(hFITS, dataset->m_fitsDataType, offset, nElements, pImage,
                   &status);

    // Capture special case of non-zero status due to data range
    // overflow Standard GDAL policy is to silently truncate, which is
    // what CFITSIO does, in addition to returning NUM_OVERFLOW (412) as
    // the status.
    if (status == NUM_OVERFLOW)
        status = 0;

    // Check for other errors
    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Error writing image data to FITS file (%d).", status);
        return CE_Failure;
    }

    // When we write a block, update the offset counter that we've written
    if (offset > dataset->m_highestOffsetWritten)
        dataset->m_highestOffsetWritten = offset;

    return CE_None;
}

/************************************************************************/
/* ==================================================================== */
/*                             FITSDataset                             */
/* ==================================================================== */
/************************************************************************/

// Some useful utility functions

// Simple static function to determine if FITS header keyword should
// be saved in meta data.
static const char *const ignorableFITSHeaders[] = {
    "SIMPLE",   "BITPIX", "NAXIS",  "NAXIS1", "NAXIS2",   "NAXIS3",  "END",
    "XTENSION", "PCOUNT", "GCOUNT", "EXTEND", "CONTINUE", "COMMENT", "",
    "LONGSTRN", "BZERO",  "BSCALE", "BLANK",  "CHECKSUM", "DATASUM",
};
static bool isIgnorableFITSHeader(const char *name)
{
    for (const char *keyword : ignorableFITSHeaders)
    {
        if (strcmp(name, keyword) == 0)
            return true;
    }
    return false;
}

/************************************************************************/
/*                            FITSDataset()                            */
/************************************************************************/

FITSDataset::FITSDataset()
{
    m_oSRS.SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);
    m_adfGeoTransform[0] = 0;
    m_adfGeoTransform[1] = 1;
    m_adfGeoTransform[2] = 0;
    m_adfGeoTransform[3] = 0;
    m_adfGeoTransform[4] = 0;
    m_adfGeoTransform[5] = 1;
}

/************************************************************************/
/*                           ~FITSDataset()                            */
/************************************************************************/

FITSDataset::~FITSDataset()
{

    int status = 0;
    if (m_hFITS)
    {
        m_apoLayers.clear();

        if (m_hduNum > 0 && eAccess == GA_Update)
        {
            // Only do this if we've successfully opened the file and update
            // capability.  Write any meta data to the file that's compatible
            // with FITS.
            fits_movabs_hdu(m_hFITS, m_hduNum, nullptr, &status);
            fits_write_key_longwarn(m_hFITS, &status);
            if (status)
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Couldn't move to HDU %d in FITS file %s (%d).\n",
                         m_hduNum, GetDescription(), status);
            }
            char **metaData = FITSDataset::GetMetadata();
            int count = CSLCount(metaData);
            for (int i = 0; i < count; ++i)
            {
                const char *field = CSLGetField(metaData, i);
                if (strlen(field) == 0)
                    continue;
                else
                {
                    char *key = nullptr;
                    const char *value = CPLParseNameValue(field, &key);
                    // FITS keys must be less than 8 chars
                    if (key != nullptr && strlen(key) <= 8 &&
                        !isIgnorableFITSHeader(key))
                    {
                        // Although FITS provides support for different value
                        // types, the GDAL Metadata mechanism works only with
                        // string values. Prior to about 2003-05-02, this driver
                        // would attempt to guess the value type from the
                        // metadata value string amd then would use the
                        // appropriate type-specific FITS keyword update
                        // routine. This was found to be troublesome (e.g. a
                        // numeric version string with leading zeros would be
                        // interpreted as a number and might get those leading
                        // zeros stripped), and so now the driver writes every
                        // value as a string. In practice this is not a problem
                        // since most FITS reading routines will convert from
                        // strings to numbers automatically, but if you want
                        // finer control, use the underlying FITS handle. Note:
                        // to avoid a compiler warning we copy the const value
                        // string to a non const one.
                        char *valueCpy = CPLStrdup(value);
                        fits_update_key_longstr(m_hFITS, key, valueCpy, nullptr,
                                                &status);
                        CPLFree(valueCpy);

                        // Check for errors.
                        if (status)
                        {
                            // Throw a warning with CFITSIO error status, then
                            // ignore status
                            CPLError(
                                CE_Warning, CPLE_AppDefined,
                                "Couldn't update key %s in FITS file %s (%d).",
                                key, GetDescription(), status);
                            status = 0;
                            return;
                        }
                    }
                    // Must free up key
                    CPLFree(key);
                }
            }

            // Writing nodata value
            if (m_gdalDataType != GDT_Float32 && m_gdalDataType != GDT_Float64)
            {
                fits_update_key(m_hFITS, TDOUBLE, "BLANK", &m_dfNoDataValue,
                                nullptr, &status);
                if (status)
                {
                    // Throw a warning with CFITSIO error status, then ignore
                    // status
                    CPLError(CE_Warning, CPLE_AppDefined,
                             "Couldn't update key BLANK in FITS file %s (%d).",
                             GetDescription(), status);
                    status = 0;
                    return;
                }
            }

            // Writing Scale and offset if defined
            int pbSuccess;
            GDALRasterBand *poSrcBand = GDALPamDataset::GetRasterBand(1);
            double dfScale = poSrcBand->GetScale(&pbSuccess);
            double dfOffset = poSrcBand->GetOffset(&pbSuccess);
            if (m_bMetadataChanged)
            {
                fits_update_key(m_hFITS, TDOUBLE, "BSCALE", &dfScale, nullptr,
                                &status);
                if (status)
                {
                    // Throw a warning with CFITSIO error status, then ignore
                    // status
                    CPLError(CE_Warning, CPLE_AppDefined,
                             "Couldn't update key BSCALE in FITS file %s (%d).",
                             GetDescription(), status);
                    status = 0;
                    return;
                }
                fits_update_key(m_hFITS, TDOUBLE, "BZERO", &dfOffset, nullptr,
                                &status);
                if (status)
                {
                    // Throw a warning with CFITSIO error status, then ignore
                    // status
                    CPLError(CE_Warning, CPLE_AppDefined,
                             "Couldn't update key BZERO in FITS file %s (%d).",
                             GetDescription(), status);
                    status = 0;
                    return;
                }
            }

            // Copy georeferencing info to PAM if the profile is not FITS
            GDALPamDataset::SetSpatialRef(GDALPamDataset::GetSpatialRef());

            // Write geographic info
            if (m_bFITSInfoChanged)
            {
                WriteFITSInfo();
            }

            // Make sure we flush the raster cache before we close the file!
            FlushCache(true);
        }

        // Close the FITS handle
        fits_close_file(m_hFITS, &status);
        if (status != 0)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "fits_close_file() failed with %d", status);
        }
    }
}

/************************************************************************/
/*                        GetRawBinaryLayout()                          */
/************************************************************************/

bool FITSDataset::GetRawBinaryLayout(GDALDataset::RawBinaryLayout &sLayout)
{
    if (m_hduNum == 0)
        return false;
    int status = 0;
    if (fits_is_compressed_image(m_hFITS, &status))
        return false;
    GDALDataType eDT = GetRasterBand(1)->GetRasterDataType();
    if (eDT == GDT_UInt16 || eDT == GDT_UInt32)
        return false;  // are supported as native signed with offset

    sLayout.osRawFilename = GetDescription();
    static_assert(sizeof(OFF_T) == 8, "OFF_T should be 64 bits !");
    OFF_T headerstart = 0;
    OFF_T datastart = 0;
    OFF_T dataend = 0;
    fits_get_hduoff(m_hFITS, &headerstart, &datastart, &dataend, &status);
    if (nBands > 1)
        sLayout.eInterleaving = RawBinaryLayout::Interleaving::BSQ;
    sLayout.eDataType = eDT;
    sLayout.bLittleEndianOrder = false;
    sLayout.nImageOffset = static_cast<GIntBig>(datastart);
    sLayout.nPixelOffset = GDALGetDataTypeSizeBytes(eDT);
    sLayout.nLineOffset = sLayout.nPixelOffset * nRasterXSize;
    sLayout.nBandOffset = sLayout.nLineOffset * nRasterYSize;
    return true;
}

/************************************************************************/
/*                           Init()                                     */
/************************************************************************/

CPLErr FITSDataset::Init(fitsfile *hFITS, bool isExistingFile, int hduNum)
{

    m_hFITS = hFITS;
    m_isExistingFile = isExistingFile;

    int status = 0;
    double offset;

    int hduType = 0;
    fits_movabs_hdu(hFITS, hduNum, &hduType, &status);
    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Couldn't move to HDU %d in FITS file %s (%d).", hduNum,
                 GetDescription(), status);
        return CE_Failure;
    }

    if (hduType != IMAGE_HDU)
    {
        CPLError(CE_Failure, CPLE_AppDefined, "HDU %d is not an image.",
                 hduNum);
        return CE_Failure;
    }

    // Get the image info for this dataset (note that all bands in a FITS
    // dataset have the same type)
    int bitpix = 0;
    int naxis = 0;
    const int maxdim = 3;
    long naxes[maxdim] = {0, 0, 0};
    fits_get_img_param(hFITS, maxdim, &bitpix, &naxis, naxes, &status);
    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Couldn't determine image parameters of FITS file %s (%d)",
                 GetDescription(), status);
        return CE_Failure;
    }

    m_hduNum = hduNum;

    fits_read_key(hFITS, TDOUBLE, "BZERO", &offset, nullptr, &status);
    if (status)
    {
        // BZERO is not mandatory offset defaulted to 0 if BZERO is missing
        status = 0;
        offset = 0.;
    }

    fits_read_key(hFITS, TDOUBLE, "BLANK", &m_dfNoDataValue, nullptr, &status);
    m_bNoDataSet = !status;
    status = 0;

    // Determine data type and nodata value if BLANK keyword is absent
    if (bitpix == BYTE_IMG)
    {
        m_gdalDataType = GDT_Byte;
        m_fitsDataType = TBYTE;
    }
    else if (bitpix == SHORT_IMG)
    {
        if (offset == 32768.)
        {
            m_gdalDataType = GDT_UInt16;
            m_fitsDataType = TUSHORT;
        }
        else
        {
            m_gdalDataType = GDT_Int16;
            m_fitsDataType = TSHORT;
        }
    }
    else if (bitpix == LONG_IMG)
    {
        if (offset == 2147483648.)
        {
            m_gdalDataType = GDT_UInt32;
            m_fitsDataType = TUINT;
        }
        else
        {
            m_gdalDataType = GDT_Int32;
            m_fitsDataType = TINT;
        }
    }
    else if (bitpix == FLOAT_IMG)
    {
        m_gdalDataType = GDT_Float32;
        m_fitsDataType = TFLOAT;
    }
    else if (bitpix == DOUBLE_IMG)
    {
        m_gdalDataType = GDT_Float64;
        m_fitsDataType = TDOUBLE;
    }
    else
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "FITS file %s has unknown data type: %d.", GetDescription(),
                 bitpix);
        return CE_Failure;
    }

    // Determine image dimensions - we assume BSQ ordering
    if (naxis == 2)
    {
        nRasterXSize = static_cast<int>(naxes[0]);
        nRasterYSize = static_cast<int>(naxes[1]);
        nBands = 1;
    }
    else if (naxis == 3)
    {
        nRasterXSize = static_cast<int>(naxes[0]);
        nRasterYSize = static_cast<int>(naxes[1]);
        nBands = static_cast<int>(naxes[2]);
    }
    else
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "FITS file %s does not have 2 or 3 dimensions.",
                 GetDescription());
        return CE_Failure;
    }

    // Create the bands
    for (int i = 0; i < nBands; ++i)
        SetBand(i + 1, new FITSRasterBand(this, i + 1));

    return CE_None;
}

/************************************************************************/
/*                         LoadMetadata()                               */
/************************************************************************/

void FITSDataset::LoadMetadata(GDALMajorObject *poTarget)
{
    // Read header information from file and use it to set metadata
    // This process understands the CONTINUE standard for long strings.
    // We don't bother to capture header names that duplicate information
    // already captured elsewhere (e.g. image dimensions and type)
    int keyNum;
    char key[100];
    char value[100];
    CPLStringList aosMD;

    int nKeys = 0;
    int nMoreKeys = 0;
    int status = 0;
    fits_get_hdrspace(m_hFITS, &nKeys, &nMoreKeys, &status);
    for (keyNum = 1; keyNum <= nKeys; keyNum++)
    {
        fits_read_keyn(m_hFITS, keyNum, key, value, nullptr, &status);
        if (status)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Error while reading key %d from FITS file %s (%d)",
                     keyNum, GetDescription(), status);
            return;
        }
        if (strcmp(key, "END") == 0)
        {
            // We should not get here in principle since the END
            // keyword shouldn't be counted in nKeys, but who knows.
            break;
        }
        else if (isIgnorableFITSHeader(key))
        {
            // Ignore it
        }
        else
        {  // Going to store something, but check for long strings etc
            // Strip off leading and trailing quote if present
            char *newValue = value;
            if (value[0] == '\'' && value[strlen(value) - 1] == '\'')
            {
                newValue = value + 1;
                value[strlen(value) - 1] = '\0';
            }
            // Check for long string
            if (strrchr(newValue, '&') == newValue + strlen(newValue) - 1)
            {
                // Value string ends in "&", so use long string conventions
                char *longString = nullptr;
                fits_read_key_longstr(m_hFITS, key, &longString, nullptr,
                                      &status);
                // Note that read_key_longstr already strips quotes
                if (status)
                {
                    CPLError(CE_Failure, CPLE_AppDefined,
                             "Error while reading long string for key %s from "
                             "FITS file %s (%d)",
                             key, GetDescription(), status);
                    return;
                }
                poTarget->SetMetadataItem(key, longString);
                free(longString);
            }
            else
            {  // Normal keyword
                poTarget->SetMetadataItem(key, newValue);
            }
        }
    }
}

/************************************************************************/
/*                           Identify()                                 */
/************************************************************************/

int FITSDataset::Identify(GDALOpenInfo *poOpenInfo)
{
    if (STARTS_WITH(poOpenInfo->pszFilename, "FITS:"))
        return true;

    const char *fitsID = "SIMPLE  =                    T";  // Spaces important!
    const size_t fitsIDLen = strlen(fitsID);  // Should be 30 chars long

    if (static_cast<size_t>(poOpenInfo->nHeaderBytes) < fitsIDLen)
        return false;
    if (memcmp(poOpenInfo->pabyHeader, fitsID, fitsIDLen) != 0)
        return false;
    return true;
}

/************************************************************************/
/*                            GetMetadata()                             */
/************************************************************************/

char **FITSDataset::GetMetadata(const char *pszDomain)

{
    if (pszDomain != nullptr && EQUAL(pszDomain, "SUBDATASETS"))
    {
        return m_aosSubdatasets.List();
    }

    return GDALPamDataset::GetMetadata(pszDomain);
}

/************************************************************************/
/*                              GetLayer()                              */
/************************************************************************/

OGRLayer *FITSDataset::GetLayer(int idx)
{
    if (idx < 0 || idx >= GetLayerCount())
        return nullptr;
    return m_apoLayers[idx].get();
}

/************************************************************************/
/*                            ICreateLayer()                            */
/************************************************************************/

OGRLayer *FITSDataset::ICreateLayer(const char *pszName,
                                    const OGRSpatialReference * /* poSRS */,
                                    OGRwkbGeometryType eGType,
                                    char **papszOptions)
{
    if (!TestCapability(ODsCCreateLayer))
        return nullptr;
    if (eGType != wkbNone)
    {
        CPLError(CE_Failure, CPLE_NotSupported, "Spatial tables not supported");
        return nullptr;
    }

    int status = 0;
    int numHDUs = 0;
    fits_get_num_hdus(m_hFITS, &numHDUs, &status);
    if (status != 0)
    {
        CPLError(CE_Failure, CPLE_AppDefined, "fits_get_num_hdus() failed: %d",
                 status);
        return nullptr;
    }

    fits_create_tbl(m_hFITS, BINARY_TBL,
                    0,        // number of initial rows
                    0,        // nfields,
                    nullptr,  // ttype,
                    nullptr,  // tform
                    nullptr,  // tunits
                    pszName, &status);
    if (status != 0)
    {
        CPLError(CE_Failure, CPLE_AppDefined, "Cannot create layer");
        return nullptr;
    }

    // If calling fits_get_num_hdus() here on a freshly new created file,
    // it reports only one HDU, missing the initial dummy HDU
    if (numHDUs == 0)
    {
        numHDUs = 2;
    }
    else
    {
        numHDUs++;
    }

    auto poLayer = new FITSLayer(this, numHDUs, pszName);
    poLayer->SetCreationOptions(papszOptions);
    m_apoLayers.emplace_back(std::unique_ptr<FITSLayer>(poLayer));
    return m_apoLayers.back().get();
}

/************************************************************************/
/*                           TestCapability()                           */
/************************************************************************/

int FITSDataset::TestCapability(const char *pszCap)
{
    if (EQUAL(pszCap, ODsCCreateLayer))
        return eAccess == GA_Update;
    return false;
}

/************************************************************************/
/*                                Open()                                */
/************************************************************************/

GDALDataset *FITSDataset::Open(GDALOpenInfo *poOpenInfo)
{

    if (!Identify(poOpenInfo))
        return nullptr;

    CPLString osFilename(poOpenInfo->pszFilename);
    int iSelectedHDU = 0;
    if (STARTS_WITH(poOpenInfo->pszFilename, "FITS:"))
    {
        const CPLStringList aosTokens(
            CSLTokenizeString2(poOpenInfo->pszFilename, ":",
                               CSLT_HONOURSTRINGS | CSLT_PRESERVEESCAPES));
        if (aosTokens.size() != 3)
        {
            return nullptr;
        }
        osFilename = aosTokens[1];
        iSelectedHDU = atoi(aosTokens[2]);
        if (iSelectedHDU <= 0)
        {
            CPLError(CE_Failure, CPLE_AppDefined, "Invalid HDU number");
            return nullptr;
        }
    }

    // Get access mode and attempt to open the file
    int status = 0;
    fitsfile *hFITS = nullptr;
    if (poOpenInfo->eAccess == GA_ReadOnly)
        fits_open_file(&hFITS, osFilename.c_str(), READONLY, &status);
    else
        fits_open_file(&hFITS, osFilename.c_str(), READWRITE, &status);
    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Error while opening FITS file %s (%d).\n", osFilename.c_str(),
                 status);
        fits_close_file(hFITS, &status);
        return nullptr;
    }
    // Create a FITSDataset object
    auto dataset = cpl::make_unique<FITSDataset>();
    dataset->m_isExistingFile = true;
    dataset->m_hFITS = hFITS;
    dataset->eAccess = poOpenInfo->eAccess;
    dataset->SetPhysicalFilename(osFilename);

    /* -------------------------------------------------------------------- */
    /*      Iterate over HDUs                                               */
    /* -------------------------------------------------------------------- */
    bool firstHDUIsDummy = false;
    int firstValidHDU = 0;
    CPLStringList aosSubdatasets;
    bool hasVector = false;
    if (iSelectedHDU == 0)
    {
        int numHDUs = 0;
        fits_get_num_hdus(hFITS, &numHDUs, &status);
        if (numHDUs <= 0)
        {
            return nullptr;
        }

        for (int iHDU = 1; iHDU <= numHDUs; iHDU++)
        {
            int hduType = 0;
            fits_movabs_hdu(hFITS, iHDU, &hduType, &status);
            if (status)
            {
                continue;
            }

            char szExtname[81] = {0};
            fits_read_key(hFITS, TSTRING, "EXTNAME", szExtname, nullptr,
                          &status);
            status = 0;
            int nExtVer = 0;
            fits_read_key(hFITS, TINT, "EXTVER", &nExtVer, nullptr, &status);
            status = 0;
            CPLString osExtname(szExtname);
            if (nExtVer > 0)
                osExtname += CPLSPrintf(" %d", nExtVer);

            if (hduType == BINARY_TBL)
            {
                hasVector = true;
                if ((poOpenInfo->nOpenFlags & GDAL_OF_VECTOR) != 0)
                {
                    dataset->m_apoLayers.push_back(std::unique_ptr<FITSLayer>(
                        new FITSLayer(dataset.get(), iHDU, osExtname.c_str())));
                }
            }

            if (hduType != IMAGE_HDU)
            {
                continue;
            }

            int bitpix = 0;
            int naxis = 0;
            const int maxdim = 3;
            long naxes[maxdim] = {0, 0, 0};
            fits_get_img_param(hFITS, maxdim, &bitpix, &naxis, naxes, &status);
            if (status)
            {
                continue;
            }

            if (naxis != 2 && naxis != 3)
            {
                if (naxis == 0 && iHDU == 1)
                {
                    firstHDUIsDummy = true;
                }
                continue;
            }

            if ((poOpenInfo->nOpenFlags & GDAL_OF_RASTER) != 0)
            {
                const int nIdx = aosSubdatasets.size() / 2 + 1;
                aosSubdatasets.AddNameValue(
                    CPLSPrintf("SUBDATASET_%d_NAME", nIdx),
                    CPLSPrintf("FITS:\"%s\":%d", poOpenInfo->pszFilename,
                               iHDU));
                CPLString osDesc(CPLSPrintf(
                    "HDU %d (%dx%d, %d band%s)", iHDU,
                    static_cast<int>(naxes[0]), static_cast<int>(naxes[1]),
                    naxis == 3 ? static_cast<int>(naxes[2]) : 1,
                    (naxis == 3 && naxes[2] > 1) ? "s" : ""));
                if (!osExtname.empty())
                {
                    osDesc += ", ";
                    osDesc += osExtname;
                }
                aosSubdatasets.AddNameValue(
                    CPLSPrintf("SUBDATASET_%d_DESC", nIdx), osDesc);
            }

            if (firstValidHDU == 0)
            {
                firstValidHDU = iHDU;
            }
        }
        if (aosSubdatasets.size() == 2)
        {
            aosSubdatasets.Clear();
        }
    }
    else
    {
        if (iSelectedHDU != 1)
        {
            int hduType = 0;
            fits_movabs_hdu(hFITS, 1, &hduType, &status);
            if (status == 0)
            {
                int bitpix = 0;
                int naxis = 0;
                const int maxdim = 3;
                long naxes[maxdim] = {0, 0, 0};
                fits_get_img_param(hFITS, maxdim, &bitpix, &naxis, naxes,
                                   &status);
                if (status == 0 && naxis == 0)
                {
                    firstHDUIsDummy = true;
                }
            }
            status = 0;
        }
        firstValidHDU = iSelectedHDU;
    }

    const bool hasRaster = firstValidHDU > 0;
    const bool hasRasterAndIsAllowed =
        hasRaster && (poOpenInfo->nOpenFlags & GDAL_OF_RASTER) != 0;

    if (!hasRasterAndIsAllowed &&
        (poOpenInfo->nOpenFlags & GDAL_OF_RASTER) != 0 &&
        (poOpenInfo->nOpenFlags & GDAL_OF_VECTOR) == 0)
    {
        if (hasVector)
        {
            std::string osPath;
            osPath.resize(1024);
            if (CPLGetExecPath(&osPath[0], static_cast<int>(osPath.size())))
            {
                osPath = CPLGetBasename(osPath.c_str());
            }
            if (osPath == "gdalinfo")
            {
                CPLError(CE_Failure, CPLE_AppDefined,
                         "This FITS dataset does not contain any image, but "
                         "contains binary table(s) that could be opened "
                         "in vector mode with ogrinfo.");
            }
            else
            {
                CPLError(CE_Failure, CPLE_AppDefined,
                         "This FITS dataset does not contain any image, but "
                         "contains binary table(s) that could be opened "
                         "in vector mode.");
            }
        }
        else
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Cannot find HDU of image type with 2 or 3 axes.");
        }
        return nullptr;
    }

    if (dataset->m_apoLayers.empty() &&
        (poOpenInfo->nOpenFlags & GDAL_OF_RASTER) == 0 &&
        (poOpenInfo->nOpenFlags & GDAL_OF_VECTOR) != 0)
    {
        if (hasRaster)
        {
            std::string osPath;
            osPath.resize(1024);
            if (CPLGetExecPath(&osPath[0], static_cast<int>(osPath.size())))
            {
                osPath = CPLGetBasename(osPath.c_str());
            }
            if (osPath == "ogrinfo")
            {
                CPLError(CE_Failure, CPLE_AppDefined,
                         "This FITS dataset does not contain any binary "
                         "table, but contains image(s) that could be opened "
                         "in raster mode with gdalinfo.");
            }
            else
            {
                CPLError(CE_Failure, CPLE_AppDefined,
                         "This FITS dataset does not contain any binary "
                         "table, but contains image(s) that could be opened "
                         "in raster mode.");
            }
        }
        else
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Cannot find binary table(s).");
        }
        return nullptr;
    }

    dataset->m_aosSubdatasets = aosSubdatasets;

    // Set up the description and initialize the dataset
    dataset->SetDescription(poOpenInfo->pszFilename);
    if (hasRasterAndIsAllowed)
    {
        if (aosSubdatasets.size() > 2)
        {
            firstValidHDU = 0;
            int hduType = 0;
            fits_movabs_hdu(hFITS, 1, &hduType, &status);
        }
        else
        {
            if (firstValidHDU != 0 &&
                dataset->Init(hFITS, true, firstValidHDU) != CE_None)
            {
                return nullptr;
            }
        }
    }

    // If the first HDU is a dummy one, load its metadata first, and then
    // add/override it by the one of the image HDU
    if (firstHDUIsDummy && firstValidHDU > 1)
    {
        int hduType = 0;
        status = 0;
        fits_movabs_hdu(hFITS, 1, &hduType, &status);
        if (status == 0)
        {
            dataset->LoadMetadata(dataset.get());
        }
        status = 0;
        fits_movabs_hdu(hFITS, firstValidHDU, &hduType, &status);
        if (status)
        {
            return nullptr;
        }
    }
    if (hasRasterAndIsAllowed)
    {
        dataset->LoadMetadata(dataset.get());
        dataset->LoadFITSInfo();
    }

    /* -------------------------------------------------------------------- */
    /*      Initialize any information.                                     */
    /* -------------------------------------------------------------------- */
    dataset->SetDescription(poOpenInfo->pszFilename);
    dataset->TryLoadXML();

    /* -------------------------------------------------------------------- */
    /*      Check for external overviews.                                   */
    /* -------------------------------------------------------------------- */
    dataset->oOvManager.Initialize(dataset.get(), poOpenInfo->pszFilename,
                                   poOpenInfo->GetSiblingFiles());

    return dataset.release();
}

/************************************************************************/
/*                               Create()                               */
/*                                                                      */
/*      Create a new FITS file.                                         */
/************************************************************************/

GDALDataset *FITSDataset::Create(const char *pszFilename, int nXSize,
                                 int nYSize, int nBandsIn, GDALDataType eType,
                                 CPL_UNUSED char **papszParamList)
{
    int status = 0;

    if (nXSize == 0 && nYSize == 0 && nBandsIn == 0 && eType == GDT_Unknown)
    {
        // Create the file - to force creation, we prepend the name with '!'
        CPLString extFilename("!");
        extFilename += pszFilename;
        fitsfile *hFITS = nullptr;
        fits_create_file(&hFITS, extFilename, &status);
        if (status)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Couldn't create FITS file %s (%d).\n", pszFilename,
                     status);
            return nullptr;
        }

        // Likely vector creation mode
        FITSDataset *dataset = new FITSDataset();
        dataset->m_hFITS = hFITS;
        dataset->eAccess = GA_Update;
        dataset->SetDescription(pszFilename);
        return dataset;
    }

    // No creation options are defined. The BSCALE/BZERO options were
    // removed on 2002-07-02 by Simon Perkins because they introduced
    // excessive complications and didn't really fit into the GDAL
    // paradigm.
    // 2018 - BZERO BSCALE keywords are now set using SetScale() and
    // SetOffset() functions

    if (nXSize < 1 || nYSize < 1 || nBandsIn < 1)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Attempt to create %dx%dx%d raster FITS file, but width, "
                 "height and bands"
                 " must be positive.",
                 nXSize, nYSize, nBandsIn);

        return nullptr;
    }

    // Determine FITS type of image
    int bitpix;
    if (eType == GDT_Byte)
    {
        bitpix = BYTE_IMG;
    }
    else if (eType == GDT_UInt16)
    {
        bitpix = USHORT_IMG;
    }
    else if (eType == GDT_Int16)
    {
        bitpix = SHORT_IMG;
    }
    else if (eType == GDT_UInt32)
    {
        bitpix = ULONG_IMG;
    }
    else if (eType == GDT_Int32)
    {
        bitpix = LONG_IMG;
    }
    else if (eType == GDT_Float32)
        bitpix = FLOAT_IMG;
    else if (eType == GDT_Float64)
        bitpix = DOUBLE_IMG;
    else
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "GDALDataType (%d) unsupported for FITS", eType);
        return nullptr;
    }

    // Create the file - to force creation, we prepend the name with '!'
    CPLString extFilename("!");
    extFilename += pszFilename;
    fitsfile *hFITS = nullptr;
    fits_create_file(&hFITS, extFilename, &status);
    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Couldn't create FITS file %s (%d).\n", pszFilename, status);
        return nullptr;
    }

    // Now create an image of appropriate size and type
    long naxes[3] = {nXSize, nYSize, nBandsIn};
    int naxis = (nBandsIn == 1) ? 2 : 3;
    fits_create_img(hFITS, bitpix, naxis, naxes, &status);

    // Check the status
    if (status)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Couldn't create image within FITS file %s (%d).", pszFilename,
                 status);
        fits_close_file(hFITS, &status);
        return nullptr;
    }

    FITSDataset *dataset = new FITSDataset();
    dataset->nRasterXSize = nXSize;
    dataset->nRasterYSize = nYSize;
    dataset->eAccess = GA_Update;
    dataset->SetDescription(pszFilename);

    // Init recalculates a lot of stuff we already know, but...
    if (dataset->Init(hFITS, false, 1) != CE_None)
    {
        delete dataset;
        return nullptr;
    }
    else
    {
        return dataset;
    }
}

/************************************************************************/
/*                              Delete()                                */
/************************************************************************/

CPLErr FITSDataset::Delete(const char *pszFilename)
{
    return VSIUnlink(pszFilename) == 0 ? CE_None : CE_Failure;
}

/************************************************************************/
/*                          WriteFITSInfo()                          */
/************************************************************************/

void FITSDataset::WriteFITSInfo()

{
    int status = 0;

    const double PI = std::atan(1.0) * 4;
    const double DEG2RAD = PI / 180.;

    double falseEast = 0;
    double falseNorth = 0;

    double cfactor, mres, mapres, UpperLeftCornerX, UpperLeftCornerY;
    double crpix1, crpix2;

    /* -------------------------------------------------------------------- */
    /*      Write out projection definition.                                */
    /* -------------------------------------------------------------------- */
    const bool bHasProjection = !m_oSRS.IsEmpty();
    if (bHasProjection)
    {

        // Set according to coordinate system (thanks to Trent Hare - USGS)

        std::string object, ctype1, ctype2;

        const char *target = m_oSRS.GetAttrValue("DATUM", 0);
        if (target)
        {
            if (strstr(target, "Moon"))
            {
                object.assign("Moon");
                ctype1.assign("SE");
                ctype2.assign("SE");
            }
            else if (strstr(target, "Mercury"))
            {
                object.assign("Mercury");
                ctype1.assign("ME");
                ctype2.assign("ME");
            }
            else if (strstr(target, "Venus"))
            {
                object.assign("Venus");
                ctype1.assign("VE");
                ctype2.assign("VE");
            }
            else if (strstr(target, "Mars"))
            {
                object.assign("Mars");
                ctype1.assign("MA");
                ctype2.assign("MA");
            }
            else if (strstr(target, "Jupiter"))
            {
                object.assign("Jupiter");
                ctype1.assign("JU");
                ctype2.assign("JU");
            }
            else if (strstr(target, "Saturn"))
            {
                object.assign("Saturn");
                ctype1.assign("SA");
                ctype2.assign("SA");
            }
            else if (strstr(target, "Uranus"))
            {
                object.assign("Uranus");
                ctype1.assign("UR");
                ctype2.assign("UR");
            }
            else if (strstr(target, "Neptune"))
            {
                object.assign("Neptune");
                ctype1.assign("NE");
                ctype2.assign("NE");
            }
            else
            {
                object.assign("Earth");
                ctype1.assign("EA");
                ctype2.assign("EA");
            }

            fits_update_key(
                m_hFITS, TSTRING, "OBJECT",
                const_cast<void *>(static_cast<const void *>(object.c_str())),
                nullptr, &status);
        }

        double aradius = m_oSRS.GetSemiMajor();
        double bradius = aradius;
        double cradius = m_oSRS.GetSemiMinor();

        cfactor = aradius * DEG2RAD;

        fits_update_key(m_hFITS, TDOUBLE, "A_RADIUS", &aradius, nullptr,
                        &status);
        if (status)
        {
            // Throw a warning with CFITSIO error status, then ignore status
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Couldn't update key A_RADIUS in FITS file %s (%d).",
                     GetDescription(), status);
            status = 0;
            return;
        }
        fits_update_key(m_hFITS, TDOUBLE, "B_RADIUS", &bradius, nullptr,
                        &status);
        if (status)
        {
            // Throw a warning with CFITSIO error status, then ignore status
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Couldn't update key B_RADIUS in FITS file %s (%d).",
                     GetDescription(), status);
            status = 0;
            return;
        }
        fits_update_key(m_hFITS, TDOUBLE, "C_RADIUS", &cradius, nullptr,
                        &status);
        if (status)
        {
            // Throw a warning with CFITSIO error status, then ignore status
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Couldn't update key C_RADIUS in FITS file %s (%d).",
                     GetDescription(), status);
            status = 0;
            return;
        }

        const char *unit = m_oSRS.GetAttrValue("UNIT", 0);

        ctype1.append("LN-");
        ctype2.append("LT-");

        // strcat(ctype1a, "PX-");
        // strcat(ctype2a, "PY-");

        std::string fitsproj;
        const char *projection = m_oSRS.GetAttrValue("PROJECTION", 0);
        double centlon = 0, centlat = 0;

        if (projection)
        {
            if (strstr(projection, "Sinusoidal"))
            {
                fitsproj.assign("SFL");
                centlon = m_oSRS.GetProjParm("central_meridian", 0, nullptr);
            }
            else if (strstr(projection, "Equirectangular"))
            {
                fitsproj.assign("CAR");
                centlat = m_oSRS.GetProjParm("standard_parallel_1", 0, nullptr);
                centlon = m_oSRS.GetProjParm("central_meridian", 0, nullptr);
            }
            else if (strstr(projection, "Orthographic"))
            {
                fitsproj.assign("SIN");
                centlat = m_oSRS.GetProjParm("standard_parallel_1", 0, nullptr);
                centlon = m_oSRS.GetProjParm("central_meridian", 0, nullptr);
            }
            else if (strstr(projection, "Mercator_1SP") ||
                     strstr(projection, "Mercator"))
            {
                fitsproj.assign("MER");
                centlat = m_oSRS.GetProjParm("standard_parallel_1", 0, nullptr);
                centlon = m_oSRS.GetProjParm("central_meridian", 0, nullptr);
            }
            else if (strstr(projection, "Polar_Stereographic") ||
                     strstr(projection, "Stereographic_South_Pole") ||
                     strstr(projection, "Stereographic_North_Pole"))
            {
                fitsproj.assign("STG");
                centlat = m_oSRS.GetProjParm("latitude_of_origin", 0, nullptr);
                centlon = m_oSRS.GetProjParm("central_meridian", 0, nullptr);
            }

            /*
                            #Transverse Mercator is supported in FITS via
               specific MER parameters. # need some more testing... #if
               EQUAL(mapProjection,"Transverse_Mercator"): #    mapProjection =
               "MER" #    centLat = hSRS.GetProjParm('standard_parallel_1') #
               centLon = hSRS.GetProjParm('central_meridian') #    TMscale =
               hSRS.GetProjParm('scale_factor') #    #Need to research when TM
               actually applies false values #    #but planetary is almost
               always 0.0 #    falseEast =  hSRS.GetProjParm('false_easting') #
               falseNorth =  hSRS.GetProjParm('false_northing')
            */

            ctype1.append(fitsproj);
            ctype2.append(fitsproj);

            fits_update_key(
                m_hFITS, TSTRING, "CTYPE1",
                const_cast<void *>(static_cast<const void *>(ctype1.c_str())),
                nullptr, &status);
            if (status)
            {
                // Throw a warning with CFITSIO error status, then ignore status
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Couldn't update key CTYPE1 in FITS file %s (%d).",
                         GetDescription(), status);
                status = 0;
                return;
            }

            fits_update_key(
                m_hFITS, TSTRING, "CTYPE2",
                const_cast<void *>(static_cast<const void *>(ctype2.c_str())),
                nullptr, &status);
            if (status)
            {
                // Throw a warning with CFITSIO error status, then ignore status
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Couldn't update key CTYPE2 in FITS file %s (%d).",
                         GetDescription(), status);
                status = 0;
                return;
            }
        }

        UpperLeftCornerX = m_adfGeoTransform[0] - falseEast;
        UpperLeftCornerY = m_adfGeoTransform[3] - falseNorth;

        if (centlon > 180.)
        {
            centlon = centlon - 180.;
        }
        if (strstr(unit, "metre"))
        {
            // convert degrees/pixel to m/pixel
            mapres = 1. / m_adfGeoTransform[1];     // mapres is pixel/meters
            mres = m_adfGeoTransform[1] / cfactor;  // mres is deg/pixel
            crpix1 = -(UpperLeftCornerX * mapres) + centlon / mres + 0.5;
            // assuming that center latitude is also the origin of the
            // coordinate system: this is not always true. More generic
            // implementation coming soon
            crpix2 = (UpperLeftCornerY * mapres) + 0.5;  // - (centlat / mres);
        }
        else if (strstr(unit, "degree"))
        {
            // convert m/pixel to pixel/degree
            mapres =
                1. / m_adfGeoTransform[1] / cfactor;  // mapres is pixel/deg
            mres = m_adfGeoTransform[1];              // mres is meters/pixel
            crpix1 = -(UpperLeftCornerX * mres) + centlon / mapres + 0.5;
            // assuming that center latitude is also the origin of the
            // coordinate system: this is not always true. More generic
            // implementation coming soon
            crpix2 = (UpperLeftCornerY * mres) + 0.5;  // - (centlat / mapres);
        }

        /// Write WCS CRPIXia CRVALia CTYPEia here

        fits_update_key(m_hFITS, TDOUBLE, "CRVAL1", &centlon, nullptr, &status);
        if (status)
        {
            // Throw a warning with CFITSIO error status, then ignore status
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Couldn't update key CRVAL1 in FITS file %s (%d).",
                     GetDescription(), status);
            status = 0;
            return;
        }
        fits_update_key(m_hFITS, TDOUBLE, "CRVAL2", &centlat, nullptr, &status);
        if (status)
        {
            // Throw a warning with CFITSIO error status, then ignore status
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Couldn't update key CRVAL2 in FITS file %s (%d).",
                     GetDescription(), status);
            status = 0;
            return;
        }
        fits_update_key(m_hFITS, TDOUBLE, "CRPIX1", &crpix1, nullptr, &status);
        if (status)
        {
            // Throw a warning with CFITSIO error status, then ignore status
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Couldn't update key CRPIX1 in FITS file %s (%d).",
                     GetDescription(), status);
            status = 0;
            return;
        }
        fits_update_key(m_hFITS, TDOUBLE, "CRPIX2", &crpix2, nullptr, &status);
        if (status)
        {
            // Throw a warning with CFITSIO error status, then ignore status
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Couldn't update key CRPIX2 in FITS file %s (%d).",
                     GetDescription(), status);
            status = 0;
            return;
        }

        /* --------------------------------------------------------------------
         */
        /*      Write geotransform if valid. */
        /* --------------------------------------------------------------------
         */
        if (m_bGeoTransformValid)
        {

            /* --------------------------------------------------------------------
             */
            /*      Write the transform. */
            /* --------------------------------------------------------------------
             */

            /// Write WCS CDELTia and PCi_ja here

            double cd[4];
            cd[0] = m_adfGeoTransform[1] / cfactor;
            cd[1] = m_adfGeoTransform[2] / cfactor;
            cd[2] = m_adfGeoTransform[4] / cfactor;
            cd[3] = m_adfGeoTransform[5] / cfactor;

            double pc[4];
            pc[0] = 1.;
            pc[1] = cd[1] / cd[0];
            pc[2] = cd[2] / cd[3];
            pc[3] = -1.;

            fits_update_key(m_hFITS, TDOUBLE, "CDELT1", &cd[0], nullptr,
                            &status);
            if (status)
            {
                // Throw a warning with CFITSIO error status, then ignore status
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Couldn't update key CDELT1 in FITS file %s (%d).",
                         GetDescription(), status);
                status = 0;
                return;
            }

            fits_update_key(m_hFITS, TDOUBLE, "CDELT2", &cd[3], nullptr,
                            &status);
            if (status)
            {
                // Throw a warning with CFITSIO error status, then ignore status
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Couldn't update key CDELT2 in FITS file %s (%d).",
                         GetDescription(), status);
                status = 0;
                return;
            }

            fits_update_key(m_hFITS, TDOUBLE, "PC1_1", &pc[0], nullptr,
                            &status);
            if (status)
            {
                // Throw a warning with CFITSIO error status, then ignore status
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Couldn't update key PC1_1 in FITS file %s (%d).",
                         GetDescription(), status);
                status = 0;
                return;
            }

            fits_update_key(m_hFITS, TDOUBLE, "PC1_2", &pc[1], nullptr,
                            &status);
            if (status)
            {
                // Throw a warning with CFITSIO error status, then ignore status
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Couldn't update key PC1_2 in FITS file %s (%d).",
                         GetDescription(), status);
                status = 0;
                return;
            }

            fits_update_key(m_hFITS, TDOUBLE, "PC2_1", &pc[2], nullptr,
                            &status);
            if (status)
            {
                // Throw a warning with CFITSIO error status, then ignore status
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Couldn't update key PC2_1 in FITS file %s (%d).",
                         GetDescription(), status);
                status = 0;
                return;
            }

            fits_update_key(m_hFITS, TDOUBLE, "PC2_2", &pc[3], nullptr,
                            &status);
            if (status)
            {
                // Throw a warning with CFITSIO error status, then ignore status
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Couldn't update key PC2_2 in FITS file %s (%d).",
                         GetDescription(), status);
                status = 0;
                return;
            }
        }
    }
}

/************************************************************************/
/*                          GetSpatialRef()                             */
/************************************************************************/

const OGRSpatialReference *FITSDataset::GetSpatialRef() const

{
    return m_oSRS.IsEmpty() ? nullptr : &m_oSRS;
}

/************************************************************************/
/*                           SetSpatialRef()                            */
/************************************************************************/

CPLErr FITSDataset::SetSpatialRef(const OGRSpatialReference *poSRS)

{
    if (poSRS == nullptr || poSRS->IsEmpty())
    {
        m_oSRS.Clear();
    }
    else
    {
        m_oSRS = *poSRS;
        m_oSRS.SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);
    }

    m_bFITSInfoChanged = true;

    return CE_None;
}

/************************************************************************/
/*                          GetGeoTransform()                           */
/************************************************************************/

CPLErr FITSDataset::GetGeoTransform(double *padfTransform)

{
    memcpy(padfTransform, m_adfGeoTransform, sizeof(double) * 6);

    if (!m_bGeoTransformValid)
        return CE_Failure;

    return CE_None;
}

/************************************************************************/
/*                          SetGeoTransform()                           */
/************************************************************************/

CPLErr FITSDataset::SetGeoTransform(double *padfTransform)

{
    memcpy(m_adfGeoTransform, padfTransform, sizeof(double) * 6);
    m_bGeoTransformValid = true;

    return CE_None;
}

/************************************************************************/
/*                             GetOffset()                              */
/************************************************************************/

double FITSRasterBand::GetOffset(int *pbSuccess)

{
    if (pbSuccess)
        *pbSuccess = m_bHaveOffsetScale;
    return m_dfOffset;
}

/************************************************************************/
/*                             SetOffset()                              */
/************************************************************************/

CPLErr FITSRasterBand::SetOffset(double dfNewValue)

{
    if (!m_bHaveOffsetScale || dfNewValue != m_dfOffset)
        m_poFDS->m_bMetadataChanged = true;

    m_bHaveOffsetScale = true;
    m_dfOffset = dfNewValue;
    return CE_None;
}

/************************************************************************/
/*                              GetScale()                              */
/************************************************************************/

double FITSRasterBand::GetScale(int *pbSuccess)

{
    if (pbSuccess)
        *pbSuccess = m_bHaveOffsetScale;
    return m_dfScale;
}

/************************************************************************/
/*                              SetScale()                              */
/************************************************************************/

CPLErr FITSRasterBand::SetScale(double dfNewValue)

{
    if (!m_bHaveOffsetScale || dfNewValue != m_dfScale)
        m_poFDS->m_bMetadataChanged = true;

    m_bHaveOffsetScale = true;
    m_dfScale = dfNewValue;
    return CE_None;
}

/************************************************************************/
/*                           GetNoDataValue()                           */
/************************************************************************/

double FITSRasterBand::GetNoDataValue(int *pbSuccess)

{
    if (m_bNoDataSet)
    {
        if (pbSuccess)
            *pbSuccess = TRUE;

        return m_dfNoDataValue;
    }

    if (m_poFDS->m_bNoDataSet)
    {
        if (pbSuccess)
            *pbSuccess = TRUE;

        return m_poFDS->m_dfNoDataValue;
    }

    return GDALPamRasterBand::GetNoDataValue(pbSuccess);
}

/************************************************************************/
/*                           SetNoDataValue()                           */
/************************************************************************/

CPLErr FITSRasterBand::SetNoDataValue(double dfNoData)

{
    if (m_poFDS->m_bNoDataSet && m_poFDS->m_dfNoDataValue == dfNoData)
    {
        m_bNoDataSet = true;
        m_dfNoDataValue = dfNoData;
        return CE_None;
    }

    m_poFDS->m_bNoDataSet = true;
    m_poFDS->m_dfNoDataValue = dfNoData;

    m_poFDS->m_bNoDataChanged = true;

    m_bNoDataSet = true;
    m_dfNoDataValue = dfNoData;
    return CE_None;
}

/************************************************************************/
/*                        DeleteNoDataValue()                           */
/************************************************************************/

CPLErr FITSRasterBand::DeleteNoDataValue()

{
    if (!m_poFDS->m_bNoDataSet)
        return CE_None;

    m_poFDS->m_bNoDataSet = false;
    m_poFDS->m_dfNoDataValue = -9999.0;

    m_poFDS->m_bNoDataChanged = true;

    m_bNoDataSet = false;
    m_dfNoDataValue = -9999.0;
    return CE_None;
}

/************************************************************************/
/*                         LoadGeoreferencing()                         */
/************************************************************************/

void FITSDataset::LoadGeoreferencing()
{
    int status = 0;
    double crpix1, crpix2, crval1, crval2, cdelt1, cdelt2, pc[4], cd[4];
    double aRadius, cRadius, invFlattening = 0.0;
    double falseEast = 0.0, falseNorth = 0.0, scale = 1.0;
    char target[81], ctype[81];
    std::string GeogName, DatumName, projName;

    const double PI = std::atan(1.0) * 4;
    const double DEG2RAD = PI / 180.;

    /* -------------------------------------------------------------------- */
    /*      Get the transform from the FITS file.                           */
    /* -------------------------------------------------------------------- */

    fits_read_key(m_hFITS, TSTRING, "OBJECT", target, nullptr, &status);
    if (status)
    {
        strncpy(target, "Undefined", 10);
        CPLDebug("FITS", "OBJECT keyword is missing");
        status = 0;
    }

    GeogName.assign("GCS_");
    GeogName.append(target);
    DatumName.assign("D_");
    DatumName.append(target);

    fits_read_key(m_hFITS, TDOUBLE, "A_RADIUS", &aRadius, nullptr, &status);
    if (status)
    {
        CPLDebug("FITS", "No Radii keyword available, metadata will not "
                         "contain DATUM information.");
        return;
    }
    else
    {
        fits_read_key(m_hFITS, TDOUBLE, "C_RADIUS", &cRadius, nullptr, &status);
        if (status)
        {
            CPLError(CE_Warning, CPLE_AppDefined,
                     "No polar radius keyword available, setting C_RADIUS = "
                     "A_RADIUS");
            cRadius = aRadius;
            status = 0;
        }
        if (aRadius != cRadius)
        {
            invFlattening = aRadius / (aRadius - cRadius);
        }
    }

    /* Waiting for linear keywords standardization only deg ctype are used */
    /* Check if WCS are there */
    fits_read_key(m_hFITS, TSTRING, "CTYPE1", ctype, nullptr, &status);
    if (!status)
    {
        /* Check if angular WCS are there */
        if (strstr(ctype, "LN"))
        {
            /* Reading reference points */
            fits_read_key(m_hFITS, TDOUBLE, "CRPIX1", &crpix1, nullptr,
                          &status);
            fits_read_key(m_hFITS, TDOUBLE, "CRPIX2", &crpix2, nullptr,
                          &status);
            fits_read_key(m_hFITS, TDOUBLE, "CRVAL1", &crval1, nullptr,
                          &status);
            fits_read_key(m_hFITS, TDOUBLE, "CRVAL2", &crval2, nullptr,
                          &status);
            if (status)
            {
                CPLError(CE_Failure, CPLE_AppDefined,
                         "No CRPIX / CRVAL keyword available, the raster "
                         "cannot be georeferenced.");
                status = 0;
            }
            else
            {
                /* Check for CDELT and PC matrix representation */
                fits_read_key(m_hFITS, TDOUBLE, "CDELT1", &cdelt1, nullptr,
                              &status);
                if (!status)
                {
                    fits_read_key(m_hFITS, TDOUBLE, "CDELT2", &cdelt2, nullptr,
                                  &status);
                    fits_read_key(m_hFITS, TDOUBLE, "PC1_1", &pc[0], nullptr,
                                  &status);
                    fits_read_key(m_hFITS, TDOUBLE, "PC1_2", &pc[1], nullptr,
                                  &status);
                    fits_read_key(m_hFITS, TDOUBLE, "PC2_1", &pc[2], nullptr,
                                  &status);
                    fits_read_key(m_hFITS, TDOUBLE, "PC2_2", &pc[3], nullptr,
                                  &status);
                    cd[0] = cdelt1 * pc[0];
                    cd[1] = cdelt1 * pc[1];
                    cd[2] = cdelt2 * pc[2];
                    cd[3] = cdelt2 * pc[3];
                    status = 0;
                }
                else
                {
                    /* Look for CD matrix representation */
                    fits_read_key(m_hFITS, TDOUBLE, "CD1_1", &cd[0], nullptr,
                                  &status);
                    fits_read_key(m_hFITS, TDOUBLE, "CD1_2", &cd[1], nullptr,
                                  &status);
                    fits_read_key(m_hFITS, TDOUBLE, "CD2_1", &cd[2], nullptr,
                                  &status);
                    fits_read_key(m_hFITS, TDOUBLE, "CD2_2", &cd[3], nullptr,
                                  &status);
                }

                double radfac = DEG2RAD * aRadius;

                m_adfGeoTransform[1] = cd[0] * radfac;
                m_adfGeoTransform[2] = cd[1] * radfac;
                m_adfGeoTransform[4] = cd[2] * radfac;
                m_adfGeoTransform[5] = -cd[3] * radfac;
                if (crval1 > 180.)
                {
                    crval1 = crval1 - 180.;
                }

                /* NOTA BENE: FITS standard define pixel integers at the center
                   of the pixel, 0.5 must be subtract to have UpperLeft corner
                 */
                m_adfGeoTransform[0] =
                    crval1 * radfac - m_adfGeoTransform[1] * (crpix1 - 0.5);
                // assuming that center latitude is also the origin of the
                // coordinate system: this is not always true. More generic
                // implementation coming soon
                m_adfGeoTransform[3] = -m_adfGeoTransform[5] * (crpix2 - 0.5);
                //+ crval2 * radfac;
                m_bGeoTransformValid = true;
            }

            char *pstr = strrchr(ctype, '-');
            if (pstr)
            {
                pstr += 1;

                /* Defining projection type
                   Following http://www.gdal.org/ogr__srs__api_8h.html (GDAL)
                   and
                   http://www.aanda.org/component/article?access=bibcode&bibcode=&bibcode=2002A%2526A...395.1077CFUL
                   (FITS)
                */

                /* Sinusoidal / SFL projection */
                if (strcmp(pstr, "SFL") == 0)
                {
                    projName.assign("Sinusoidal_");
                    m_oSRS.SetSinusoidal(crval1, falseEast, falseNorth);

                    /* Mercator, Oblique (Hotine) Mercator, Transverse Mercator
                     */
                    /* Mercator / MER projection */
                }
                else if (strcmp(pstr, "MER") == 0)
                {
                    projName.assign("Mercator_");
                    m_oSRS.SetMercator(crval2, crval1, scale, falseEast,
                                       falseNorth);

                    /* Equirectangular / CAR projection */
                }
                else if (strcmp(pstr, "CAR") == 0)
                {
                    projName.assign("Equirectangular_");
                    /*
                    The standard_parallel_1 defines where the local radius is
                    calculated not the center of Y Cartesian system (which is
                    latitude_of_origin) But FITS WCS only supports projections
                    on the sphere we assume here that the local radius is the
                    one computed at the projection center
                    */
                    m_oSRS.SetEquirectangular2(crval2, crval1, crval2,
                                               falseEast, falseNorth);
                    /* Lambert Azimuthal Equal Area / ZEA projection */
                }
                else if (strcmp(pstr, "ZEA") == 0)
                {
                    projName.assign("Lambert_Azimuthal_Equal_Area_");
                    m_oSRS.SetLAEA(crval2, crval1, falseEast, falseNorth);

                    /* Lambert Conformal Conic 1SP / COO projection */
                }
                else if (strcmp(pstr, "COO") == 0)
                {
                    projName.assign("Lambert_Conformal_Conic_1SP_");
                    m_oSRS.SetLCC1SP(crval2, crval1, scale, falseEast,
                                     falseNorth);

                    /* Orthographic / SIN projection */
                }
                else if (strcmp(pstr, "SIN") == 0)
                {
                    projName.assign("Orthographic_");
                    m_oSRS.SetOrthographic(crval2, crval1, falseEast,
                                           falseNorth);

                    /* Point Perspective / AZP projection */
                }
                else if (strcmp(pstr, "AZP") == 0)
                {
                    projName.assign("perspective_point_height_");
                    m_oSRS.SetProjection(SRS_PP_PERSPECTIVE_POINT_HEIGHT);
                    /* # appears to need height... maybe center lon/lat */

                    /* Polar Stereographic / STG projection */
                }
                else if (strcmp(pstr, "STG") == 0)
                {
                    projName.assign("Polar_Stereographic_");
                    m_oSRS.SetStereographic(crval2, crval1, scale, falseEast,
                                            falseNorth);
                }
                else
                {
                    CPLError(CE_Failure, CPLE_AppDefined,
                             "Unknown projection.");
                }

                projName.append(target);
                m_oSRS.SetProjParm(SRS_PP_FALSE_EASTING, 0.0);
                m_oSRS.SetProjParm(SRS_PP_FALSE_NORTHING, 0.0);

                m_oSRS.SetNode("PROJCS", projName.c_str());

                m_oSRS.SetGeogCS(GeogName.c_str(), DatumName.c_str(), target,
                                 aRadius, invFlattening, "Reference_Meridian",
                                 0.0, "degree", 0.0174532925199433);
            }
            else
            {
                CPLError(CE_Failure, CPLE_AppDefined, "Unknown projection.");
            }
        }
    }
    else
    {
        CPLError(CE_Warning, CPLE_AppDefined,
                 "No CTYPE keywords: no geospatial information available.");
    }
}

/************************************************************************/
/*                     LoadFITSInfo()                                   */
/************************************************************************/

void FITSDataset::LoadFITSInfo()

{
    int status = 0;
    int bitpix;
    double dfScale, dfOffset;

    LoadGeoreferencing();

    CPLAssert(!m_bMetadataChanged);
    CPLAssert(!m_bNoDataChanged);

    m_bMetadataChanged = false;
    m_bNoDataChanged = false;

    bitpix = this->m_fitsDataType;
    FITSRasterBand *poBand = cpl::down_cast<FITSRasterBand *>(GetRasterBand(1));

    if (bitpix != TUSHORT && bitpix != TUINT)
    {
        fits_read_key(m_hFITS, TDOUBLE, "BSCALE", &dfScale, nullptr, &status);
        if (status)
        {
            status = 0;
            dfScale = 1.;
        }
        fits_read_key(m_hFITS, TDOUBLE, "BZERO", &dfOffset, nullptr, &status);
        if (status)
        {
            status = 0;
            dfOffset = 0.;
        }
        if (dfScale != 1. || dfOffset != 0.)
        {
            poBand->m_bHaveOffsetScale = true;
            poBand->m_dfScale = dfScale;
            poBand->m_dfOffset = dfOffset;
        }
    }

    fits_read_key(m_hFITS, TDOUBLE, "BLANK", &m_dfNoDataValue, nullptr,
                  &status);
    m_bNoDataSet = !status;
}

/************************************************************************/
/*                          GDALRegister_FITS()                         */
/************************************************************************/

void GDALRegister_FITS()

{
    if (GDALGetDriverByName("FITS") != nullptr)
        return;

    GDALDriver *poDriver = new GDALDriver();

    poDriver->SetDescription("FITS");
    poDriver->SetMetadataItem(GDAL_DCAP_RASTER, "YES");
    poDriver->SetMetadataItem(GDAL_DCAP_VECTOR, "YES");
    poDriver->SetMetadataItem(GDAL_DCAP_CREATE_LAYER, "YES");
    poDriver->SetMetadataItem(GDAL_DCAP_CREATE_FIELD, "YES");
    poDriver->SetMetadataItem(GDAL_DMD_LONGNAME,
                              "Flexible Image Transport System");
    poDriver->SetMetadataItem(GDAL_DMD_HELPTOPIC, "drivers/raster/fits.html");
    poDriver->SetMetadataItem(GDAL_DMD_CREATIONDATATYPES,
                              "Byte UInt16 Int16 UInt32 Int32 Float32 Float64");
    poDriver->SetMetadataItem(GDAL_DMD_EXTENSIONS, "fits");

    poDriver->SetMetadataItem(GDAL_DMD_CREATIONFIELDDATATYPES,
                              "Integer Integer64 Real String IntegerList "
                              "Integer64List RealList");
    poDriver->SetMetadataItem(GDAL_DMD_CREATIONFIELDDATASUBTYPES,
                              "Boolean Int16 Float32");

    poDriver->SetMetadataItem(
        GDAL_DS_LAYER_CREATIONOPTIONLIST,
        "<LayerCreationOptionList>"
        "  <Option name='REPEAT_*' type='int' description='Repeat value for "
        "fields of type List'/>"
        "  <Option name='COMPUTE_REPEAT' type='string-select' "
        "description='Determine when the repeat value for fields is computed'>"
        "    <Value>AT_FIELD_CREATION</Value>"
        "    <Value>AT_FIRST_FEATURE_CREATION</Value>"
        "  </Option>"
        "</LayerCreationOptionList>");
    poDriver->pfnOpen = FITSDataset::Open;
    poDriver->pfnIdentify = FITSDataset::Identify;
    poDriver->pfnCreate = FITSDataset::Create;
    poDriver->pfnCreateCopy = nullptr;
    poDriver->pfnDelete = FITSDataset::Delete;

    GetGDALDriverManager()->RegisterDriver(poDriver);
}
