/src/gdal/frmts/grib/gribdataset.cpp

Source (jump to first uncovered line)
/******************************************************************************
 *
 * Project:  GRIB Driver
 * Purpose:  GDALDataset driver for GRIB translator for read support
 * Author:   Bas Retsios, retsios@itc.nl
 *
 ******************************************************************************
 * Copyright (c) 2007, ITC
 * Copyright (c) 2008-2017, Even Rouault <even dot rouault at spatialys dot com>
 *
 * SPDX-License-Identifier: MIT
 ******************************************************************************
 *
 */

#include "cpl_port.h"
#include "gribdataset.h"
#include "gribdrivercore.h"

#include <cassert>
#include <cerrno>
#include <cmath>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif

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

#include "cpl_conv.h"
#include "cpl_error.h"
#include "cpl_multiproc.h"
#include "cpl_string.h"
#include "cpl_vsi.h"
#include "cpl_time.h"
#include "degrib/degrib/degrib2.h"
#include "degrib/degrib/inventory.h"
#include "degrib/degrib/meta.h"
#include "degrib/degrib/metaname.h"
#include "degrib/degrib/myerror.h"
#include "degrib/degrib/type.h"
CPL_C_START
#include "degrib/g2clib/grib2.h"
#include "degrib/g2clib/pdstemplates.h"
CPL_C_END
#include "gdal.h"
#include "gdal_frmts.h"
#include "gdal_pam.h"
#include "gdal_priv.h"
#include "ogr_spatialref.h"
#include "memdataset.h"

static CPLMutex *hGRIBMutex = nullptr;

/************************************************************************/
/*                         ConvertUnitInText()                          */
/************************************************************************/

static CPLString ConvertUnitInText(bool bMetricUnits, const char *pszTxt)
{
    if (pszTxt == nullptr)
        return CPLString();
    if (!bMetricUnits)
        return pszTxt;

    CPLString osRes(pszTxt);
    size_t iPos = osRes.find("[K]");
    if (iPos != std::string::npos)
        osRes = osRes.substr(0, iPos) + "[C]" + osRes.substr(iPos + 3);
    return osRes;
}

/************************************************************************/
/*                         Lon360to180()                               */
/************************************************************************/

static inline double Lon360to180(double lon)
{
    if (lon == 180)
        return 180;
    return fmod(lon + 180, 360) - 180;
}

/************************************************************************/
/*                           GRIBRasterBand()                            */
/************************************************************************/

GRIBRasterBand::GRIBRasterBand(GRIBDataset *poDSIn, int nBandIn,
                               inventoryType *psInv)
    : start(psInv->start), subgNum(psInv->subgNum),
      longFstLevel(CPLStrdup(psInv->longFstLevel)), m_Grib_Data(nullptr),
      m_Grib_MetaData(nullptr), nGribDataXSize(poDSIn->nRasterXSize),
      nGribDataYSize(poDSIn->nRasterYSize), m_nGribVersion(psInv->GribVersion),
      m_bHasLookedForNoData(false), m_dfNoData(0.0), m_bHasNoData(false)

{
    poDS = poDSIn;
    nBand = nBandIn;

    // Let user do -ot Float32 if needed for saving space, GRIB contains
    // Float64 (though not fully utilized most of the time).
    eDataType = GDT_Float64;

    nBlockXSize = poDSIn->nRasterXSize;
    nBlockYSize = 1;

    if (psInv->unitName != nullptr && psInv->comment != nullptr &&
        psInv->element != nullptr)
    {
        bLoadedMetadata = true;
        const char *pszGribNormalizeUnits =
            CPLGetConfigOption("GRIB_NORMALIZE_UNITS", "YES");
        bool bMetricUnits = CPLTestBool(pszGribNormalizeUnits);

        SetMetadataItem("GRIB_UNIT",
                        ConvertUnitInText(bMetricUnits, psInv->unitName));
        SetMetadataItem("GRIB_COMMENT",
                        ConvertUnitInText(bMetricUnits, psInv->comment));
        SetMetadataItem("GRIB_ELEMENT", psInv->element);
        SetMetadataItem("GRIB_SHORT_NAME", psInv->shortFstLevel);
        SetMetadataItem("GRIB_REF_TIME",
                        CPLString().Printf("%.0f", psInv->refTime));
        SetMetadataItem("GRIB_VALID_TIME",
                        CPLString().Printf("%.0f", psInv->validTime));
        SetMetadataItem("GRIB_FORECAST_SECONDS",
                        CPLString().Printf("%.0f", psInv->foreSec));
    }
}

/************************************************************************/
/*                           FindMetaData()                             */
/************************************************************************/

void GRIBRasterBand::FindMetaData()
{
    if (bLoadedMetadata)
        return;
    if (m_Grib_MetaData == nullptr)
    {
        grib_MetaData *metaData;
        GRIBDataset *poGDS = static_cast<GRIBDataset *>(poDS);
        GRIBRasterBand::ReadGribData(poGDS->fp, start, subgNum, nullptr,
                                     &metaData);
        if (metaData == nullptr)
            return;
        m_Grib_MetaData = metaData;
    }
    bLoadedMetadata = true;
    m_nGribVersion = m_Grib_MetaData->GribVersion;

    const char *pszGribNormalizeUnits =
        CPLGetConfigOption("GRIB_NORMALIZE_UNITS", "YES");
    bool bMetricUnits = CPLTestBool(pszGribNormalizeUnits);

    GDALRasterBand::SetMetadataItem(
        "GRIB_UNIT",
        ConvertUnitInText(bMetricUnits, m_Grib_MetaData->unitName));
    GDALRasterBand::SetMetadataItem(
        "GRIB_COMMENT",
        ConvertUnitInText(bMetricUnits, m_Grib_MetaData->comment));

    GDALRasterBand::SetMetadataItem("GRIB_ELEMENT", m_Grib_MetaData->element);
    GDALRasterBand::SetMetadataItem("GRIB_SHORT_NAME",
                                    m_Grib_MetaData->shortFstLevel);

    if (m_nGribVersion == 2)
    {
        GDALRasterBand::SetMetadataItem(
            "GRIB_REF_TIME",
            CPLString().Printf("%.0f", m_Grib_MetaData->pds2.refTime));
        GDALRasterBand::SetMetadataItem(
            "GRIB_VALID_TIME",
            CPLString().Printf("%.0f", m_Grib_MetaData->pds2.sect4.validTime));
    }
    else if (m_nGribVersion == 1)
    {
        GDALRasterBand::SetMetadataItem(
            "GRIB_REF_TIME",
            CPLString().Printf("%.0f", m_Grib_MetaData->pds1.refTime));
        GDALRasterBand::SetMetadataItem(
            "GRIB_VALID_TIME",
            CPLString().Printf("%.0f", m_Grib_MetaData->pds1.validTime));
    }

    GDALRasterBand::SetMetadataItem(
        "GRIB_FORECAST_SECONDS",
        CPLString().Printf("%d", m_Grib_MetaData->deltTime));
}

/************************************************************************/
/*                          FindTrueStart()                             */
/*                                                                      */
/*      Scan after the official start of the message to find its        */
/*      true starting offset.                                           */
/************************************************************************/
vsi_l_offset GRIBRasterBand::FindTrueStart(VSILFILE *fp, vsi_l_offset start)
{
    // GRIB messages can be preceded by "garbage". GRIB2Inventory()
    // does not return the offset to the real start of the message
    char szHeader[1024 + 1];
    VSIFSeekL(fp, start, SEEK_SET);
    const int nRead =
        static_cast<int>(VSIFReadL(szHeader, 1, sizeof(szHeader) - 1, fp));
    szHeader[nRead] = 0;
    // Find the real offset of the fist message
    int nOffsetFirstMessage = 0;
    for (int j = 0; j + 3 < nRead; j++)
    {
        if (STARTS_WITH_CI(szHeader + j, "GRIB")
#ifdef ENABLE_TDLP
            || STARTS_WITH_CI(szHeader + j, "TDLP")
#endif
        )
        {
            nOffsetFirstMessage = j;
            break;
        }
    }
    return start + nOffsetFirstMessage;
}

/************************************************************************/
/*                      FindPDSTemplateGRIB2()                          */
/*                                                                      */
/*      Scan the file for the PDS template info and represent it as     */
/*      metadata.                                                       */
/************************************************************************/

void GRIBRasterBand::FindPDSTemplateGRIB2()

{
    CPLAssert(m_nGribVersion == 2);

    if (bLoadedPDS)
        return;
    bLoadedPDS = true;

    GRIBDataset *poGDS = static_cast<GRIBDataset *>(poDS);
    start = FindTrueStart(poGDS->fp, start);

    // Read section 0
    GByte abySection0[16];
    if (VSIFSeekL(poGDS->fp, start, SEEK_SET) != 0 ||
        VSIFReadL(abySection0, 16, 1, poGDS->fp) != 1)
    {
        CPLDebug("GRIB", "Cannot read leading bytes of section 0");
        return;
    }
    GByte nDiscipline = abySection0[7 - 1];
    CPLString osDiscipline;
    osDiscipline = CPLString().Printf("%d", nDiscipline);
    static const char *const table00[] = {"Meteorological",
                                          "Hydrological",
                                          "Land Surface",
                                          "Space products",
                                          "Space products",
                                          "Reserved",
                                          "Reserved",
                                          "Reserved",
                                          "Reserved",
                                          "Reserved",
                                          "Oceanographic Products"};
    m_nDisciplineCode = nDiscipline;
    if (nDiscipline < CPL_ARRAYSIZE(table00))
    {
        m_osDisciplineName = table00[nDiscipline];
        osDiscipline += CPLString("(") +
                        CPLString(table00[nDiscipline]).replaceAll(' ', '_') +
                        ")";
    }

    GDALRasterBand::SetMetadataItem("GRIB_DISCIPLINE", osDiscipline.c_str());

    GByte abyHead[5] = {0};

    if (VSIFReadL(abyHead, 5, 1, poGDS->fp) != 1)
    {
        CPLDebug("GRIB", "Cannot read 5 leading bytes past section 0");
        return;
    }

    GUInt32 nSectSize = 0;
    if (abyHead[4] == 1)
    {
        memcpy(&nSectSize, abyHead, 4);
        CPL_MSBPTR32(&nSectSize);
        if (nSectSize >= 21 && nSectSize <= 100000 /* arbitrary upper limit */)
        {
            GByte *pabyBody = static_cast<GByte *>(CPLMalloc(nSectSize));
            memcpy(pabyBody, abyHead, 5);
            VSIFReadL(pabyBody + 5, 1, nSectSize - 5, poGDS->fp);

            CPLString osIDS;
            unsigned short nCenter = static_cast<unsigned short>(
                pabyBody[6 - 1] * 256 + pabyBody[7 - 1]);
            if (nCenter != GRIB2MISSING_u1 && nCenter != GRIB2MISSING_u2)
            {
                osIDS += "CENTER=";
                m_nCenter = nCenter;
                osIDS += CPLSPrintf("%d", nCenter);
                const char *pszCenter = centerLookup(nCenter);
                if (pszCenter)
                {
                    m_osCenterName = pszCenter;
                    osIDS += CPLString("(") + pszCenter + ")";
                }
            }

            unsigned short nSubCenter = static_cast<unsigned short>(
                pabyBody[8 - 1] * 256 + pabyBody[9 - 1]);
            if (nSubCenter != GRIB2MISSING_u2)
            {
                if (!osIDS.empty())
                    osIDS += " ";
                osIDS += "SUBCENTER=";
                osIDS += CPLSPrintf("%d", nSubCenter);
                m_nSubCenter = nSubCenter;
                const char *pszSubCenter = subCenterLookup(nCenter, nSubCenter);
                if (pszSubCenter)
                {
                    m_osSubCenterName = pszSubCenter;
                    osIDS += CPLString("(") + pszSubCenter + ")";
                }
            }

            if (!osIDS.empty())
                osIDS += " ";
            osIDS += "MASTER_TABLE=";
            osIDS += CPLSPrintf("%d", pabyBody[10 - 1]);
            osIDS += " ";
            osIDS += "LOCAL_TABLE=";
            osIDS += CPLSPrintf("%d", pabyBody[11 - 1]);
            osIDS += " ";
            osIDS += "SIGNF_REF_TIME=";
            unsigned nSignRefTime = pabyBody[12 - 1];
            osIDS += CPLSPrintf("%d", nSignRefTime);
            static const char *const table12[] = {
                "Analysis", "Start of Forecast", "Verifying time of forecast",
                "Observation time"};
            if (nSignRefTime < CPL_ARRAYSIZE(table12))
            {
                m_osSignRefTimeName = table12[nSignRefTime];
                osIDS += CPLString("(") +
                         CPLString(table12[nSignRefTime]).replaceAll(' ', '_') +
                         ")";
            }
            osIDS += " ";
            osIDS += "REF_TIME=";
            m_osRefTime =
                CPLSPrintf("%04d-%02d-%02dT%02d:%02d:%02dZ",
                           pabyBody[13 - 1] * 256 + pabyBody[14 - 1],
                           pabyBody[15 - 1], pabyBody[16 - 1], pabyBody[17 - 1],
                           pabyBody[18 - 1], pabyBody[19 - 1]);
            osIDS += m_osRefTime;
            osIDS += " ";
            osIDS += "PROD_STATUS=";
            unsigned nProdStatus = pabyBody[20 - 1];
            osIDS += CPLSPrintf("%d", nProdStatus);
            static const char *const table13[] = {
                "Operational",     "Operational test",
                "Research",        "Re-analysis",
                "TIGGE",           "TIGGE test",
                "S2S operational", "S2S test",
                "UERRA",           "UERRA test"};
            if (nProdStatus < CPL_ARRAYSIZE(table13))
            {
                m_osProductionStatus = table13[nProdStatus];
                osIDS += CPLString("(") +
                         CPLString(table13[nProdStatus]).replaceAll(' ', '_') +
                         ")";
            }
            osIDS += " ";
            osIDS += "TYPE=";
            unsigned nType = pabyBody[21 - 1];
            osIDS += CPLSPrintf("%d", nType);
            static const char *const table14[] = {
                "Analysis",
                "Forecast",
                "Analysis and forecast",
                "Control forecast",
                "Perturbed forecast",
                "Control and perturbed forecast",
                "Processed satellite observations",
                "Processed radar observations",
                "Event Probability"};
            if (nType < CPL_ARRAYSIZE(table14))
            {
                m_osType = table14[nType];
                osIDS += CPLString("(") +
                         CPLString(table14[nType]).replaceAll(' ', '_') + ")";
            }

            GDALRasterBand::SetMetadataItem("GRIB_IDS", osIDS);

            CPLFree(pabyBody);
        }

        if (VSIFReadL(abyHead, 5, 1, poGDS->fp) != 1)
        {
            CPLDebug("GRIB", "Cannot read 5 leading bytes past section 1");
            return;
        }
    }

    if (subgNum > 0)
    {
        // If we are a subgrid, then iterate over all preceding subgrids
        for (int iSubMessage = 0; iSubMessage < subgNum;)
        {
            memcpy(&nSectSize, abyHead, 4);
            CPL_MSBPTR32(&nSectSize);
            if (nSectSize < 5)
            {
                CPLDebug("GRIB", "Invalid section size for iSubMessage = %d",
                         iSubMessage);
                return;
            }
            if (VSIFSeekL(poGDS->fp, nSectSize - 5, SEEK_CUR) != 0)
            {
                CPLDebug("GRIB",
                         "Cannot read past section for iSubMessage = %d",
                         iSubMessage);
                return;
            }
            if (abyHead[4] < 2 || abyHead[4] > 7)
            {
                CPLDebug("GRIB", "Invalid section number for iSubMessage = %d",
                         iSubMessage);
                return;
            }
            if (abyHead[4] == 7)
            {
                ++iSubMessage;
            }
            if (VSIFReadL(abyHead, 5, 1, poGDS->fp) != 1)
            {
                CPLDebug("GRIB",
                         "Cannot read 5 leading bytes for iSubMessage = %d",
                         iSubMessage);
                return;
            }
        }
    }

    // Skip to section 4
    while (abyHead[4] != 4)
    {
        memcpy(&nSectSize, abyHead, 4);
        CPL_MSBPTR32(&nSectSize);

        const int nCurSection = abyHead[4];
        if (nSectSize < 5)
        {
            CPLDebug("GRIB", "Invalid section size for section %d",
                     nCurSection);
            return;
        }
        if (VSIFSeekL(poGDS->fp, nSectSize - 5, SEEK_CUR) != 0 ||
            VSIFReadL(abyHead, 5, 1, poGDS->fp) != 1)
        {
            CPLDebug("GRIB", "Cannot read section %d", nCurSection);
            return;
        }
    }

    // Collect section 4 octet information.  We read the file
    // ourselves since the GRIB API does not appear to preserve all
    // this for us.
    // if( abyHead[4] == 4 )
    {
        memcpy(&nSectSize, abyHead, 4);
        CPL_MSBPTR32(&nSectSize);
        if (nSectSize >= 9 && nSectSize <= 100000 /* arbitrary upper limit */)
        {
            GByte *pabyBody = static_cast<GByte *>(CPLMalloc(nSectSize));
            memcpy(pabyBody, abyHead, 5);
            if (VSIFReadL(pabyBody + 5, 1, nSectSize - 5, poGDS->fp) !=
                nSectSize - 5)
            {
                CPLDebug("GRIB", "Cannot read section 4");
                CPLFree(pabyBody);
                return;
            }

            GUInt16 nCoordCount = 0;
            memcpy(&nCoordCount, pabyBody + 6 - 1, 2);
            CPL_MSBPTR16(&nCoordCount);

            GUInt16 nPDTN = 0;
            memcpy(&nPDTN, pabyBody + 8 - 1, 2);
            CPL_MSBPTR16(&nPDTN);

            GDALRasterBand::SetMetadataItem("GRIB_PDS_PDTN",
                                            CPLString().Printf("%d", nPDTN));
            m_nPDTN = nPDTN;

            CPLString osOctet;
            const int nTemplateFoundByteCount =
                nSectSize - 9U >= nCoordCount * 4U
                    ? static_cast<int>(nSectSize - 9 - nCoordCount * 4)
                    : 0;
            for (int i = 0; i < nTemplateFoundByteCount; i++)
            {
                char szByte[10] = {'\0'};

                if (i == 0)
                    snprintf(szByte, sizeof(szByte), "%d", pabyBody[i + 9]);
                else
                    snprintf(szByte, sizeof(szByte), " %d", pabyBody[i + 9]);
                osOctet += szByte;
            }

            GDALRasterBand::SetMetadataItem("GRIB_PDS_TEMPLATE_NUMBERS",
                                            osOctet);

            g2int iofst = 0;
            g2int pdsnum = 0;
            g2int *pdstempl = nullptr;
            g2int mappdslen = 0;
            g2float *coordlist = nullptr;
            g2int numcoord = 0;
            if (getpdsindex(nPDTN) < 0)
            {
                CPLError(CE_Warning, CPLE_NotSupported,
                         "Template 4.%d is not recognized currently", nPDTN);
            }
            else if (g2_unpack4(pabyBody, nSectSize, &iofst, &pdsnum, &pdstempl,
                                &mappdslen, &coordlist, &numcoord) == 0)
            {
                gtemplate *mappds = extpdstemplate(pdsnum, pdstempl);
                if (mappds)
                {
                    int nTemplateByteCount = 0;
                    for (int i = 0; i < mappds->maplen; i++)
                        nTemplateByteCount += abs(mappds->map[i]);
                    for (int i = 0; i < mappds->extlen; i++)
                        nTemplateByteCount += abs(mappds->ext[i]);
                    if (nTemplateByteCount == nTemplateFoundByteCount)
                    {
                        CPLString osValues;
                        for (g2int i = 0; i < mappds->maplen + mappds->extlen;
                             i++)
                        {
                            if (i > 0)
                                osValues += " ";
                            const int nEltSize =
                                (i < mappds->maplen)
                                    ? mappds->map[i]
                                    : mappds->ext[i - mappds->maplen];
                            if (nEltSize == 4)
                            {
                                m_anPDSTemplateAssembledValues.push_back(
                                    static_cast<GUInt32>(pdstempl[i]));
                                osValues += CPLSPrintf(
                                    "%u", static_cast<GUInt32>(pdstempl[i]));
                            }
                            else
                            {
                                m_anPDSTemplateAssembledValues.push_back(
                                    pdstempl[i]);
                                osValues += CPLSPrintf("%d", pdstempl[i]);
                            }
                        }
                        GDALRasterBand::SetMetadataItem(
                            "GRIB_PDS_TEMPLATE_ASSEMBLED_VALUES", osValues);
                    }
                    else
                    {
                        CPLDebug(
                            "GRIB",
                            "Cannot expose GRIB_PDS_TEMPLATE_ASSEMBLED_VALUES "
                            "as we would expect %d bytes from the "
                            "tables, but %d are available",
                            nTemplateByteCount, nTemplateFoundByteCount);
                    }

                    free(mappds->ext);
                    free(mappds);
                }
            }
            free(pdstempl);
            free(coordlist);

            CPLFree(pabyBody);

            FindNoDataGrib2(false);
        }
        else
        {
            CPLDebug("GRIB", "Invalid section size for section %d", 4);
        }
    }
}

/************************************************************************/
/*                        FindNoDataGrib2()                             */
/************************************************************************/

void GRIBRasterBand::FindNoDataGrib2(bool bSeekToStart)
{
    // There is no easy way in the degrib API to retrieve the nodata value
    // without decompressing the data point section (which is slow), so
    // retrieve nodata value by parsing section 5 (Data Representation Section)
    // We also check section 6 to see if there is a bitmap
    GRIBDataset *poGDS = static_cast<GRIBDataset *>(poDS);
    CPLAssert(m_nGribVersion == 2);

    if (m_bHasLookedForNoData)
        return;
    m_bHasLookedForNoData = true;

    if (bSeekToStart)
    {
        // Skip over section 0
        VSIFSeekL(poGDS->fp, start + 16, SEEK_SET);
    }

    GByte abyHead[5] = {0};
    VSIFReadL(abyHead, 5, 1, poGDS->fp);

    // Skip to section 5
    GUInt32 nSectSize = 0;
    while (abyHead[4] != 5)
    {
        memcpy(&nSectSize, abyHead, 4);
        CPL_MSBPTR32(&nSectSize);

        if (nSectSize < 5 ||
            VSIFSeekL(poGDS->fp, nSectSize - 5, SEEK_CUR) != 0 ||
            VSIFReadL(abyHead, 5, 1, poGDS->fp) != 1)
            break;
    }

    // See http://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_sect5.shtml
    if (abyHead[4] == 5)
    {
        memcpy(&nSectSize, abyHead, 4);
        CPL_MSBPTR32(&nSectSize);
        if (nSectSize >= 11 && nSectSize <= 100000 /* arbitrary upper limit */)
        {
            GByte *pabyBody = static_cast<GByte *>(CPLMalloc(nSectSize));
            memcpy(pabyBody, abyHead, 5);
            VSIFReadL(pabyBody + 5, 1, nSectSize - 5, poGDS->fp);

            GUInt16 nDRTN = 0;
            memcpy(&nDRTN, pabyBody + 10 - 1, 2);
            CPL_MSBPTR16(&nDRTN);

            GDALRasterBand::SetMetadataItem("DRS_DRTN", CPLSPrintf("%d", nDRTN),
                                            "GRIB");
            if ((nDRTN == GS5_SIMPLE || nDRTN == GS5_CMPLX ||
                 nDRTN == GS5_CMPLXSEC || nDRTN == GS5_JPEG2000 ||
                 nDRTN == GS5_PNG) &&
                nSectSize >= 20)
            {
                float fRef;
                memcpy(&fRef, pabyBody + 12 - 1, 4);
                CPL_MSBPTR32(&fRef);
                GDALRasterBand::SetMetadataItem(
                    "DRS_REF_VALUE", CPLSPrintf("%.10f", fRef), "GRIB");

                GUInt16 nBinaryScaleFactorUnsigned;
                memcpy(&nBinaryScaleFactorUnsigned, pabyBody + 16 - 1, 2);
                CPL_MSBPTR16(&nBinaryScaleFactorUnsigned);
                const int nBSF =
                    (nBinaryScaleFactorUnsigned & 0x8000)
                        ? -static_cast<int>(nBinaryScaleFactorUnsigned & 0x7FFF)
                        : static_cast<int>(nBinaryScaleFactorUnsigned);
                GDALRasterBand::SetMetadataItem("DRS_BINARY_SCALE_FACTOR",
                                                CPLSPrintf("%d", nBSF), "GRIB");

                GUInt16 nDecimalScaleFactorUnsigned;
                memcpy(&nDecimalScaleFactorUnsigned, pabyBody + 18 - 1, 2);
                CPL_MSBPTR16(&nDecimalScaleFactorUnsigned);
                const int nDSF =
                    (nDecimalScaleFactorUnsigned & 0x8000)
                        ? -static_cast<int>(nDecimalScaleFactorUnsigned &
                                            0x7FFF)
                        : static_cast<int>(nDecimalScaleFactorUnsigned);
                GDALRasterBand::SetMetadataItem("DRS_DECIMAL_SCALE_FACTOR",
                                                CPLSPrintf("%d", nDSF), "GRIB");

                const int nBits = pabyBody[20 - 1];
                GDALRasterBand::SetMetadataItem(
                    "DRS_NBITS", CPLSPrintf("%d", nBits), "GRIB");
            }

            // 2 = Grid Point Data - Complex Packing
            // 3 = Grid Point Data - Complex Packing and Spatial Differencing
            if ((nDRTN == GS5_CMPLX || nDRTN == GS5_CMPLXSEC) &&
                nSectSize >= 31)
            {
                const int nMiss = pabyBody[23 - 1];
                if (nMiss == 1 || nMiss == 2)
                {
                    const int original_field_type = pabyBody[21 - 1];
                    if (original_field_type == 0)  // Floating Point
                    {
                        float fTemp;
                        memcpy(&fTemp, &pabyBody[24 - 1], 4);
                        CPL_MSBPTR32(&fTemp);
                        m_dfNoData = fTemp;
                        m_bHasNoData = true;
                        if (nMiss == 2)
                        {
                            memcpy(&fTemp, &pabyBody[28 - 1], 4);
                            CPL_MSBPTR32(&fTemp);
                            CPLDebug("GRIB",
                                     "Secondary missing value also set for "
                                     "band %d : %f",
                                     nBand, fTemp);
                        }
                    }
                    else if (original_field_type == 1)  // Integer
                    {
                        int iTemp;
                        memcpy(&iTemp, &pabyBody[24 - 1], 4);
                        CPL_MSBPTR32(&iTemp);
                        m_dfNoData = iTemp;
                        m_bHasNoData = true;
                        if (nMiss == 2)
                        {
                            memcpy(&iTemp, &pabyBody[28 - 1], 4);
                            CPL_MSBPTR32(&iTemp);
                            CPLDebug("GRIB",
                                     "Secondary missing value also set for "
                                     "band %d : %d",
                                     nBand, iTemp);
                        }
                    }
                    else
                    {
                        // FIXME What to do? Blindly convert to float?
                        CPLDebug("GRIB",
                                 "Complex Packing - Type of Original Field "
                                 "Values for band %d:  %u",
                                 nBand, original_field_type);
                    }
                }
            }

            if (nDRTN == GS5_CMPLXSEC && nSectSize >= 48)
            {
                const int nOrder = pabyBody[48 - 1];
                GDALRasterBand::SetMetadataItem(
                    "DRS_SPATIAL_DIFFERENCING_ORDER", CPLSPrintf("%d", nOrder),
                    "GRIB");
            }

            CPLFree(pabyBody);
        }
        else if (nSectSize > 5)
        {
            VSIFSeekL(poGDS->fp, nSectSize - 5, SEEK_CUR);
        }
    }

    if (!m_bHasNoData)
    {
        // Check bitmap section
        GByte abySection6[6] = {0};
        VSIFReadL(abySection6, 6, 1, poGDS->fp);
        // Is there a bitmap ?
        if (abySection6[4] == 6 && abySection6[5] == 0)
        {
            m_dfNoData = 9999.0;  // Same value as in metaparse.cpp:ParseGrid()
            m_bHasNoData = true;
        }
    }
}

/************************************************************************/
/*                         GetDescription()                             */
/************************************************************************/

const char *GRIBRasterBand::GetDescription() const
{
    if (longFstLevel == nullptr)
        return GDALPamRasterBand::GetDescription();

    return longFstLevel;
}

/************************************************************************/
/*                             LoadData()                               */
/************************************************************************/

CPLErr GRIBRasterBand::LoadData()

{
    if (!m_Grib_Data)
    {
        GRIBDataset *poGDS = static_cast<GRIBDataset *>(poDS);

        if (poGDS->bCacheOnlyOneBand)
        {
            // In "one-band-at-a-time" strategy, if the last recently used
            // band is not that one, uncache it. We could use a smarter strategy
            // based on a LRU, but that's a bit overkill for now.
            poGDS->poLastUsedBand->UncacheData();
            poGDS->nCachedBytes = 0;
        }
        else
        {
            // Once we have cached more than nCachedBytesThreshold bytes, we
            // will switch to "one-band-at-a-time" strategy, instead of caching
            // all bands that have been accessed.
            if (poGDS->nCachedBytes > poGDS->nCachedBytesThreshold)
            {
                GUIntBig nMinCacheSize =
                    1 + static_cast<GUIntBig>(poGDS->nRasterXSize) *
                            poGDS->nRasterYSize * poGDS->nBands *
                            GDALGetDataTypeSizeBytes(eDataType) / 1024 / 1024;
                CPLDebug("GRIB",
                         "Maximum band cache size reached for this dataset. "
                         "Caching only one band at a time from now, which can "
                         "negatively affect performance. Consider "
                         "increasing GRIB_CACHEMAX to a higher value (in MB), "
                         "at least " CPL_FRMT_GUIB " in that instance",
                         nMinCacheSize);
                for (int i = 0; i < poGDS->nBands; i++)
                {
                    reinterpret_cast<GRIBRasterBand *>(
                        poGDS->GetRasterBand(i + 1))
                        ->UncacheData();
                }
                poGDS->nCachedBytes = 0;
                poGDS->bCacheOnlyOneBand = TRUE;
            }
        }

        // we don't seem to have any way to detect errors in this!
        if (m_Grib_MetaData != nullptr)
        {
            MetaFree(m_Grib_MetaData);
            delete m_Grib_MetaData;
            m_Grib_MetaData = nullptr;
        }
        ReadGribData(poGDS->fp, start, subgNum, &m_Grib_Data, &m_Grib_MetaData);
        if (!m_Grib_Data)
        {
            CPLError(CE_Failure, CPLE_AppDefined, "Out of memory.");
            if (m_Grib_MetaData != nullptr)
            {
                MetaFree(m_Grib_MetaData);
                delete m_Grib_MetaData;
                m_Grib_MetaData = nullptr;
            }
            return CE_Failure;
        }

        // Check the band matches the dataset as a whole, size wise. (#3246)
        nGribDataXSize = m_Grib_MetaData->gds.Nx;
        nGribDataYSize = m_Grib_MetaData->gds.Ny;
        if (nGribDataXSize <= 0 || nGribDataYSize <= 0)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Band %d of GRIB dataset is %dx%d.", nBand, nGribDataXSize,
                     nGribDataYSize);
            MetaFree(m_Grib_MetaData);
            delete m_Grib_MetaData;
            m_Grib_MetaData = nullptr;
            return CE_Failure;
        }

        poGDS->nCachedBytes += static_cast<GIntBig>(nGribDataXSize) *
                               nGribDataYSize * sizeof(double);
        poGDS->poLastUsedBand = this;

        if (nGribDataXSize != nRasterXSize || nGribDataYSize != nRasterYSize)
        {
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Band %d of GRIB dataset is %dx%d, while the first band "
                     "and dataset is %dx%d.  Georeferencing of band %d may "
                     "be incorrect, and data access may be incomplete.",
                     nBand, nGribDataXSize, nGribDataYSize, nRasterXSize,
                     nRasterYSize, nBand);
        }
    }

    return CE_None;
}

/************************************************************************/
/*                       IsGdalinfoInteractive()                        */
/************************************************************************/

#ifdef BUILD_APPS
static bool IsGdalinfoInteractive()
{
    static const bool bIsGdalinfoInteractive = []()
    {
        if (CPLIsInteractive(stdout))
        {
            std::string osPath;
            osPath.resize(1024);
            if (CPLGetExecPath(&osPath[0], static_cast<int>(osPath.size())))
            {
                osPath = CPLGetBasenameSafe(osPath.c_str());
            }
            return osPath == "gdalinfo";
        }
        return false;
    }();
    return bIsGdalinfoInteractive;
}
#endif

/************************************************************************/
/*                             GetMetaData()                            */
/************************************************************************/
char **GRIBRasterBand::GetMetadata(const char *pszDomain)
{
    FindMetaData();
    if ((pszDomain == nullptr || pszDomain[0] == 0) && m_nGribVersion == 2 &&
        CPLTestBool(CPLGetConfigOption("GRIB_PDS_ALL_BANDS", "ON")))
    {
#ifdef BUILD_APPS
        // Detect slow execution of e.g.
        // "gdalinfo /vsis3/noaa-hrrr-bdp-pds/hrrr.20220804/conus/hrrr.t00z.wrfsfcf01.grib2"
        GRIBDataset *poGDS = static_cast<GRIBDataset *>(poDS);
        if (poGDS->m_bSideCarIdxUsed && !poGDS->m_bWarnedGdalinfoNomd &&
            poGDS->GetRasterCount() > 10 &&
            !VSIIsLocal(poGDS->GetDescription()) && IsGdalinfoInteractive())
        {
            if (poGDS->m_nFirstMetadataQueriedTimeStamp)
            {
                if (time(nullptr) - poGDS->m_nFirstMetadataQueriedTimeStamp > 2)
                {
                    poGDS->m_bWarnedGdalinfoNomd = true;

                    CPLError(
                        CE_Warning, CPLE_AppDefined,
                        "If metadata does not matter, faster result could be "
                        "obtained by adding the -nomd switch to gdalinfo");
                }
            }
            else
            {
                poGDS->m_nFirstMetadataQueriedTimeStamp = time(nullptr);
            }
        }
#endif

        FindPDSTemplateGRIB2();
    }
    return GDALPamRasterBand::GetMetadata(pszDomain);
}

/************************************************************************/
/*                             GetMetaDataItem()                        */
/************************************************************************/
const char *GRIBRasterBand::GetMetadataItem(const char *pszName,
                                            const char *pszDomain)
{
    if (!((!pszDomain || pszDomain[0] == 0) &&
          (EQUAL(pszName, "STATISTICS_MINIMUM") ||
           EQUAL(pszName, "STATISTICS_MAXIMUM"))))
    {
        FindMetaData();
        if (m_nGribVersion == 2 &&
            CPLTestBool(CPLGetConfigOption("GRIB_PDS_ALL_BANDS", "ON")))
        {
            FindPDSTemplateGRIB2();
        }
    }
    return GDALPamRasterBand::GetMetadataItem(pszName, pszDomain);
}

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

CPLErr GRIBRasterBand::IReadBlock(int /* nBlockXOff */, int nBlockYOff,
                                  void *pImage)

{
    CPLErr eErr = LoadData();
    if (eErr != CE_None)
        return eErr;

    GRIBDataset *poGDS = static_cast<GRIBDataset *>(poDS);

    // The image as read is always upside down to our normal
    // orientation so we need to effectively flip it at this
    // point.  We also need to deal with bands that are a different
    // size than the dataset as a whole.

    if (nGribDataXSize == nRasterXSize && nGribDataYSize == nRasterYSize &&
        poGDS->nSplitAndSwapColumn == 0)
    {
        // Simple 1:1 case.
        memcpy(pImage,
               m_Grib_Data + static_cast<size_t>(nRasterXSize) *
                                 (nRasterYSize - nBlockYOff - 1),
               nRasterXSize * sizeof(double));

        return CE_None;
    }

    memset(pImage, 0, sizeof(double) * nRasterXSize);

    if (nBlockYOff >= nGribDataYSize)  // Off image?
        return CE_None;

    int nSplitAndSwapColumn = poGDS->nSplitAndSwapColumn;
    if (nRasterXSize != nGribDataXSize)
        nSplitAndSwapColumn = 0;

    const int nCopyWords = std::min(nRasterXSize, nGribDataXSize);

    memcpy(pImage,
           m_Grib_Data +
               static_cast<size_t>(nGribDataXSize) *
                   (nGribDataYSize - nBlockYOff - 1) +
               nSplitAndSwapColumn,
           (nCopyWords - nSplitAndSwapColumn) * sizeof(double));

    if (nSplitAndSwapColumn > 0)
        memcpy(reinterpret_cast<void *>(reinterpret_cast<double *>(pImage) +
                                        nCopyWords - nSplitAndSwapColumn),
               m_Grib_Data + static_cast<size_t>(nGribDataXSize) *
                                 (nGribDataYSize - nBlockYOff - 1),
               nSplitAndSwapColumn * sizeof(double));

    return CE_None;
}

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

double GRIBRasterBand::GetNoDataValue(int *pbSuccess)
{
    if (m_bHasLookedForNoData)
    {
        if (pbSuccess)
            *pbSuccess = m_bHasNoData;
        return m_dfNoData;
    }

    m_bHasLookedForNoData = true;
    if (m_Grib_MetaData == nullptr)
    {
        GRIBDataset *poGDS = static_cast<GRIBDataset *>(poDS);

#ifdef BUILD_APPS
        // Detect slow execution of e.g.
        // "gdalinfo /vsis3/noaa-hrrr-bdp-pds/hrrr.20220804/conus/hrrr.t00z.wrfsfcf01.grib2"

        if (poGDS->m_bSideCarIdxUsed && !poGDS->m_bWarnedGdalinfoNonodata &&
            poGDS->GetRasterCount() > 10 &&
            !VSIIsLocal(poGDS->GetDescription()) && IsGdalinfoInteractive())
        {
            if (poGDS->m_nFirstNodataQueriedTimeStamp)
            {
                if (time(nullptr) - poGDS->m_nFirstNodataQueriedTimeStamp > 2)
                {
                    poGDS->m_bWarnedGdalinfoNonodata = true;

                    CPLError(CE_Warning, CPLE_AppDefined,
                             "If nodata value does not matter, faster result "
                             "could be obtained by adding the -nonodata switch "
                             "to gdalinfo");
                }
            }
            else
            {
                poGDS->m_nFirstNodataQueriedTimeStamp = time(nullptr);
            }
        }
#endif

        ReadGribData(poGDS->fp, start, subgNum, nullptr, &m_Grib_MetaData);
        if (m_Grib_MetaData == nullptr)
        {
            m_bHasNoData = false;
            m_dfNoData = 0;
            if (pbSuccess)
                *pbSuccess = m_bHasNoData;
            return m_dfNoData;
        }
    }

    if (m_Grib_MetaData->gridAttrib.f_miss == 0)
    {
        m_bHasNoData = false;
        m_dfNoData = 0;
        if (pbSuccess)
            *pbSuccess = m_bHasNoData;
        return m_dfNoData;
    }

    if (m_Grib_MetaData->gridAttrib.f_miss == 2)
    {
        // What TODO?
        CPLDebug("GRIB", "Secondary missing value also set for band %d : %f",
                 nBand, m_Grib_MetaData->gridAttrib.missSec);
    }

    m_bHasNoData = true;
    m_dfNoData = m_Grib_MetaData->gridAttrib.missPri;
    if (pbSuccess)
        *pbSuccess = m_bHasNoData;
    return m_dfNoData;
}

/************************************************************************/
/*                            ReadGribData()                            */
/************************************************************************/

void GRIBRasterBand::ReadGribData(VSILFILE *fp, vsi_l_offset start, int subgNum,
                                  double **data, grib_MetaData **metaData)
{
    // Initialization, for calling the ReadGrib2Record function.
    sInt4 f_endMsg = 1;  // 1 if we read the last grid in a GRIB message, or we
                         // haven't read any messages.
    // int subgNum = 0; // The subgrid in the message that we are interested in.
    sChar f_unit = 2;       // None = 0, English = 1, Metric = 2
    double majEarth = 0.0;  // -radEarth if < 6000 ignore, otherwise use this
                            // to override the radEarth in the GRIB1 or GRIB2
                            // message.  Needed because NCEP uses 6371.2 but
                            // GRIB1 could only state 6367.47.
    double minEarth = 0.0;  // -minEarth if < 6000 ignore, otherwise use this
                            // to override the minEarth in the GRIB1 or GRIB2
                            // message.
    sChar f_SimpleVer = 4;  // Which version of the simple NDFD Weather table
                            // to use. (1 is 6/2003) (2 is 1/2004) (3 is
                            // 2/2004) (4 is 11/2004) (default 4)
    LatLon lwlf;            // Lower left corner (cookie slicing) -lwlf
    LatLon uprt;            // Upper right corner (cookie slicing) -uprt
    IS_dataType is;  // Un-parsed meta data for this GRIB2 message. As well
                     // as some memory used by the unpacker.

    lwlf.lat = -100;  // lat == -100 instructs the GRIB decoder that we don't
                      // want a subgrid

    IS_Init(&is);

    const char *pszGribNormalizeUnits =
        CPLGetConfigOption("GRIB_NORMALIZE_UNITS", "YES");
    if (!CPLTestBool(pszGribNormalizeUnits))
        f_unit = 0;  // Do not normalize units to metric.

    start = FindTrueStart(fp, start);
    // Read GRIB message from file position "start".
    VSIFSeekL(fp, start, SEEK_SET);
    uInt4 grib_DataLen = 0;  // Size of Grib_Data.
    *metaData = new grib_MetaData();
    MetaInit(*metaData);
    const int simpWWA = 0;  // seem to be unused in degrib
    ReadGrib2Record(fp, f_unit, data, &grib_DataLen, *metaData, &is, subgNum,
                    majEarth, minEarth, f_SimpleVer, simpWWA, &f_endMsg, &lwlf,
                    &uprt);

    // No intention to show errors, just swallow it and free the memory.
    char *errMsg = errSprintf(nullptr);
    if (errMsg != nullptr)
        CPLDebug("GRIB", "%s", errMsg);
    free(errMsg);
    IS_Free(&is);
}

/************************************************************************/
/*                            UncacheData()                             */
/************************************************************************/

void GRIBRasterBand::UncacheData()
{
    if (m_Grib_Data)
        free(m_Grib_Data);
    m_Grib_Data = nullptr;
    if (m_Grib_MetaData)
    {
        MetaFree(m_Grib_MetaData);
        delete m_Grib_MetaData;
    }
    m_Grib_MetaData = nullptr;
}

/************************************************************************/
/*                           ~GRIBRasterBand()                          */
/************************************************************************/

GRIBRasterBand::~GRIBRasterBand()
{
    if (longFstLevel != nullptr)
        CPLFree(longFstLevel);
    UncacheData();
}

gdal::grib::InventoryWrapper::~InventoryWrapper() = default;

/************************************************************************/
/*                           InventoryWrapperGrib                       */
/************************************************************************/
class InventoryWrapperGrib : public gdal::grib::InventoryWrapper
{
  public:
    explicit InventoryWrapperGrib(VSILFILE *fp) : gdal::grib::InventoryWrapper()
    {
        result_ = GRIB2Inventory(fp, &inv_, &inv_len_, 0 /* all messages */,
                                 &num_messages_);
    }

    ~InventoryWrapperGrib() override;
};

InventoryWrapperGrib::~InventoryWrapperGrib()
{
    if (inv_ == nullptr)
        return;
    for (uInt4 i = 0; i < inv_len_; i++)
    {
        GRIB2InventoryFree(inv_ + i);
    }
    free(inv_);
}

/************************************************************************/
/*                           InventoryWrapperSidecar                    */
/************************************************************************/

class InventoryWrapperSidecar : public gdal::grib::InventoryWrapper
{
  public:
    explicit InventoryWrapperSidecar(VSILFILE *fp, uint64_t nStartOffset,
                                     int64_t nSize)
        : gdal::grib::InventoryWrapper()
    {
        result_ = -1;
        VSIFSeekL(fp, 0, SEEK_END);
        size_t length = static_cast<size_t>(VSIFTellL(fp));
        if (length > 4 * 1024 * 1024)
            return;
        std::string osSidecar;
        osSidecar.resize(length);
        VSIFSeekL(fp, 0, SEEK_SET);
        if (VSIFReadL(&osSidecar[0], length, 1, fp) != 1)
            return;

        const CPLStringList aosMsgs(
            CSLTokenizeString2(osSidecar.c_str(), "\n",
                               CSLT_PRESERVEQUOTES | CSLT_STRIPLEADSPACES));
        inv_ = static_cast<inventoryType *>(
            CPLCalloc(aosMsgs.size(), sizeof(inventoryType)));

        for (const char *pszMsg : aosMsgs)
        {
            // We are parsing
            // "msgNum[.subgNum]:start:dontcare:name1:name2:name3" For NOMADS:
            // "msgNum[.subgNum]:start:reftime:var:level:time"
            const CPLStringList aosTokens(CSLTokenizeString2(
                pszMsg, ":", CSLT_PRESERVEQUOTES | CSLT_ALLOWEMPTYTOKENS));
            CPLStringList aosNum;

            if (aosTokens.size() < 6)
                goto err_sidecar;

            aosNum = CPLStringList(CSLTokenizeString2(aosTokens[0], ".", 0));
            if (aosNum.size() < 1)
                goto err_sidecar;

            // FindMetaData will retrieve the correct version number
            char *endptr;
            strtol(aosNum[0], &endptr, 10);
            if (*endptr != 0)
                goto err_sidecar;

            if (aosNum.size() < 2)
                inv_[inv_len_].subgNum = 0;
            else
            {
                auto subgNum = strtol(aosNum[1], &endptr, 10);
                if (*endptr != 0)
                    goto err_sidecar;
                if (subgNum <= 0 || subgNum > 65536)
                    goto err_sidecar;
                // .idx file use a 1-based indexing, whereas DEGRIB uses a
                // 0-based one
                subgNum--;
                inv_[inv_len_].subgNum = static_cast<unsigned short>(subgNum);
            }

            inv_[inv_len_].start = strtoll(aosTokens[1], &endptr, 10);
            if (*endptr != 0)
                goto err_sidecar;

            if (inv_[inv_len_].start < nStartOffset)
                continue;
            if (nSize > 0 && inv_[inv_len_].start >= nStartOffset + nSize)
                break;

            inv_[inv_len_].start -= nStartOffset;

            inv_[inv_len_].unitName = nullptr;
            inv_[inv_len_].comment = nullptr;
            inv_[inv_len_].element = nullptr;
            inv_[inv_len_].shortFstLevel = nullptr;
            // This is going into the description field ->
            // the only one available before loading the metadata
            inv_[inv_len_].longFstLevel = VSIStrdup(CPLSPrintf(
                "%s:%s:%s", aosTokens[3], aosTokens[4], aosTokens[5]));
            ++inv_len_;

            continue;

        err_sidecar:
            CPLDebug("GRIB",
                     "Failed parsing sidecar entry '%s', "
                     "falling back to constructing an inventory",
                     pszMsg);
            return;
        }

        result_ = inv_len_;
    }

    ~InventoryWrapperSidecar() override;
};

InventoryWrapperSidecar::~InventoryWrapperSidecar()
{
    if (inv_ == nullptr)
        return;

    for (unsigned i = 0; i < inv_len_; i++)
        VSIFree(inv_[i].longFstLevel);

    VSIFree(inv_);
}

/************************************************************************/
/* ==================================================================== */
/*                              GRIBDataset                             */
/* ==================================================================== */
/************************************************************************/

GRIBDataset::GRIBDataset()
    : fp(nullptr), nCachedBytes(0),
      // Switch caching strategy once 100 MB threshold is reached.
      // Why 100 MB? --> Why not.
      nCachedBytesThreshold(static_cast<GIntBig>(atoi(
                                CPLGetConfigOption("GRIB_CACHEMAX", "100"))) *
                            1024 * 1024),
      bCacheOnlyOneBand(FALSE), nSplitAndSwapColumn(0), poLastUsedBand(nullptr)
{
}

/************************************************************************/
/*                            ~GRIBDataset()                             */
/************************************************************************/

GRIBDataset::~GRIBDataset()

{
    FlushCache(true);
    if (fp != nullptr)
        VSIFCloseL(fp);
}

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

CPLErr GRIBDataset::GetGeoTransform(GDALGeoTransform &gt) const

{
    gt = m_gt;
    return CE_None;
}

/************************************************************************/
/*                                Inventory()                           */
/************************************************************************/

std::unique_ptr<gdal::grib::InventoryWrapper>
GRIBDataset::Inventory(GDALOpenInfo *poOpenInfo)
{
    std::unique_ptr<gdal::grib::InventoryWrapper> pInventories;

    VSIFSeekL(fp, 0, SEEK_SET);
    std::string osSideCarFilename(poOpenInfo->pszFilename);
    uint64_t nStartOffset = 0;
    int64_t nSize = -1;
    if (STARTS_WITH(poOpenInfo->pszFilename, "/vsisubfile/"))
    {
        const char *pszPtr = poOpenInfo->pszFilename + strlen("/vsisubfile/");
        const char *pszComma = strchr(pszPtr, ',');
        if (pszComma)
        {
            const CPLStringList aosTokens(CSLTokenizeString2(
                std::string(pszPtr, pszComma - pszPtr).c_str(), "_", 0));
            if (aosTokens.size() == 2)
            {
                nStartOffset = std::strtoull(aosTokens[0], nullptr, 10);
                nSize = std::strtoll(aosTokens[1], nullptr, 10);
                osSideCarFilename = pszComma + 1;
            }
        }
    }
    osSideCarFilename += ".idx";
    VSILFILE *fpSideCar = nullptr;
    if (CPLTestBool(CSLFetchNameValueDef(poOpenInfo->papszOpenOptions,
                                         "USE_IDX", "YES")) &&
        ((fpSideCar = VSIFOpenL(osSideCarFilename.c_str(), "rb")) != nullptr))
    {
        CPLDebug("GRIB", "Reading inventories from sidecar file %s",
                 osSideCarFilename.c_str());
        // Contains an GRIB2 message inventory of the file.
        pInventories = std::make_unique<InventoryWrapperSidecar>(
            fpSideCar, nStartOffset, nSize);
        if (pInventories->result() <= 0 || pInventories->length() == 0)
            pInventories = nullptr;
        VSIFCloseL(fpSideCar);
#ifdef BUILD_APPS
        m_bSideCarIdxUsed = true;
#endif
    }
    else
        CPLDebug("GRIB", "Failed opening sidecar %s",
                 osSideCarFilename.c_str());

    if (pInventories == nullptr)
    {
        CPLDebug("GRIB", "Reading inventories from GRIB file %s",
                 poOpenInfo->pszFilename);
        // Contains an GRIB2 message inventory of the file.
        pInventories = std::make_unique<InventoryWrapperGrib>(fp);
    }

    return pInventories;
}

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

GDALDataset *GRIBDataset::Open(GDALOpenInfo *poOpenInfo)

{
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    // During fuzzing, do not use Identify to reject crazy content.
    if (!GRIBDriverIdentify(poOpenInfo))
        return nullptr;
#endif
    if (poOpenInfo->fpL == nullptr)
        return nullptr;

    // A fast "probe" on the header that is partially read in memory.
    char *buff = nullptr;
    uInt4 buffLen = 0;
    sInt4 sect0[SECT0LEN_WORD] = {0};
    uInt4 gribLen = 0;
    int version = 0;

    // grib is not thread safe, make sure not to cause problems
    // for other thread safe formats
    CPLMutexHolderD(&hGRIBMutex);

    VSILFILE *memfp = VSIFileFromMemBuffer(nullptr, poOpenInfo->pabyHeader,
                                           poOpenInfo->nHeaderBytes, FALSE);
    if (memfp == nullptr ||
        ReadSECT0(memfp, &buff, &buffLen, -1, sect0, &gribLen, &version) < 0)
    {
        if (memfp != nullptr)
        {
            VSIFCloseL(memfp);
        }
        free(buff);
        char *errMsg = errSprintf(nullptr);
        if (errMsg != nullptr && strstr(errMsg, "Ran out of file") == nullptr)
            CPLDebug("GRIB", "%s", errMsg);
        free(errMsg);
        return nullptr;
    }
    VSIFCloseL(memfp);
    free(buff);

    // Confirm the requested access is supported.
    if (poOpenInfo->eAccess == GA_Update)
    {
        ReportUpdateNotSupportedByDriver("GRIB");
        return nullptr;
    }

    if (poOpenInfo->nOpenFlags & GDAL_OF_MULTIDIM_RASTER)
    {
        return OpenMultiDim(poOpenInfo);
    }

    // Create a corresponding GDALDataset.
    GRIBDataset *poDS = new GRIBDataset();

    poDS->fp = poOpenInfo->fpL;
    poOpenInfo->fpL = nullptr;

    // Make an inventory of the GRIB file.
    // The inventory does not contain all the information needed for
    // creating the RasterBands (especially the x and y size), therefore
    // the first GRIB band is also read for some additional metadata.
    // The band-data that is read is stored into the first RasterBand,
    // simply so that the same portion of the file is not read twice.

    auto pInventories = poDS->Inventory(poOpenInfo);
    if (pInventories->result() <= 0)
    {
        char *errMsg = errSprintf(nullptr);
        if (errMsg != nullptr)
            CPLDebug("GRIB", "%s", errMsg);
        free(errMsg);

        CPLError(CE_Failure, CPLE_OpenFailed,
                 "%s is a grib file, "
                 "but no raster dataset was successfully identified.",
                 poOpenInfo->pszFilename);
        // Release hGRIBMutex otherwise we'll deadlock with GDALDataset own
        // hGRIBMutex.
        CPLReleaseMutex(hGRIBMutex);
        delete poDS;
        CPLAcquireMutex(hGRIBMutex, 1000.0);
        return nullptr;
    }

    // Create band objects.
    const uInt4 nCount = std::min(pInventories->length(), 65536U);
    for (uInt4 i = 0; i < nCount; ++i)
    {
        inventoryType *psInv = pInventories->get(i);
        GRIBRasterBand *gribBand = nullptr;
        const uInt4 bandNr = i + 1;
        assert(bandNr <= 65536);

        if (bandNr == 1)
        {
            // Important: set DataSet extents before creating first RasterBand
            // in it.
            grib_MetaData *metaData = nullptr;
            GRIBRasterBand::ReadGribData(poDS->fp, 0, psInv->subgNum, nullptr,
                                         &metaData);
            if (metaData == nullptr || metaData->gds.Nx < 1 ||
                metaData->gds.Ny < 1)
            {
                CPLError(CE_Failure, CPLE_OpenFailed,
                         "%s is a grib file, "
                         "but no raster dataset was successfully identified.",
                         poOpenInfo->pszFilename);
                // Release hGRIBMutex otherwise we'll deadlock with GDALDataset
                // own hGRIBMutex.
                CPLReleaseMutex(hGRIBMutex);
                delete poDS;
                CPLAcquireMutex(hGRIBMutex, 1000.0);
                if (metaData != nullptr)
                {
                    MetaFree(metaData);
                    delete metaData;
                }
                return nullptr;
            }
            psInv->GribVersion = metaData->GribVersion;

            // Set the DataSet's x,y size, georeference and projection from
            // the first GRIB band.
            poDS->SetGribMetaData(metaData);
            gribBand = new GRIBRasterBand(poDS, bandNr, psInv);

            if (psInv->GribVersion == 2)
                gribBand->FindPDSTemplateGRIB2();

            gribBand->m_Grib_MetaData = metaData;
        }
        else
        {
            gribBand = new GRIBRasterBand(poDS, bandNr, psInv);
        }
        poDS->SetBand(bandNr, gribBand);
    }

    // Initialize any PAM information.
    poDS->SetDescription(poOpenInfo->pszFilename);

    // Release hGRIBMutex otherwise we'll deadlock with GDALDataset own
    // hGRIBMutex.
    CPLReleaseMutex(hGRIBMutex);
    poDS->TryLoadXML(poOpenInfo->GetSiblingFiles());

    // Check for external overviews.
    poDS->oOvManager.Initialize(poDS, poOpenInfo);
    CPLAcquireMutex(hGRIBMutex, 1000.0);

    return poDS;
}

/************************************************************************/
/*                          GRIBSharedResource                          */
/************************************************************************/

struct GRIBSharedResource
{
    VSILFILE *m_fp = nullptr;
    vsi_l_offset m_nOffsetCurData = static_cast<vsi_l_offset>(-1);
    std::vector<double> m_adfCurData{};
    std::string m_osFilename;
    std::shared_ptr<GDALPamMultiDim> m_poPAM{};

    GRIBSharedResource(const std::string &osFilename, VSILFILE *fp);
    ~GRIBSharedResource();

    const std::vector<double> &LoadData(vsi_l_offset nOffset, int subgNum);

    const std::shared_ptr<GDALPamMultiDim> &GetPAM()
    {
        return m_poPAM;
    }
};

GRIBSharedResource::GRIBSharedResource(const std::string &osFilename,
                                       VSILFILE *fp)
    : m_fp(fp), m_osFilename(osFilename),
      m_poPAM(std::make_shared<GDALPamMultiDim>(osFilename))
{
}

GRIBSharedResource::~GRIBSharedResource()
{
    if (m_fp)
        VSIFCloseL(m_fp);
}

/************************************************************************/
/*                                GRIBGroup                             */
/************************************************************************/

class GRIBArray;

class GRIBGroup final : public GDALGroup
{
    friend class GRIBArray;
    std::shared_ptr<GRIBSharedResource> m_poShared{};
    std::vector<std::shared_ptr<GDALMDArray>> m_poArrays{};
    std::vector<std::shared_ptr<GDALDimension>> m_dims{};
    std::map<std::string, std::shared_ptr<GDALDimension>> m_oMapDims{};
    int m_nHorizDimCounter = 0;
    std::shared_ptr<GDALGroup> m_memRootGroup{};

  public:
    explicit GRIBGroup(const std::shared_ptr<GRIBSharedResource> &poShared)
        : GDALGroup(std::string(), "/"), m_poShared(poShared)
    {
        std::unique_ptr<GDALDataset> poTmpDS(
            MEMDataset::CreateMultiDimensional("", nullptr, nullptr));
        m_memRootGroup = poTmpDS->GetRootGroup();
    }

    void AddArray(const std::shared_ptr<GDALMDArray> &array)
    {
        m_poArrays.emplace_back(array);
    }

    std::vector<std::string>
    GetMDArrayNames(CSLConstList papszOptions) const override;
    std::shared_ptr<GDALMDArray>
    OpenMDArray(const std::string &osName,
                CSLConstList papszOptions) const override;

    std::vector<std::shared_ptr<GDALDimension>>
    GetDimensions(CSLConstList) const override
    {
        return m_dims;
    }
};

/************************************************************************/
/*                                GRIBArray                             */
/************************************************************************/

class GRIBArray final : public GDALPamMDArray
{
    std::shared_ptr<GRIBSharedResource> m_poShared;
    std::vector<std::shared_ptr<GDALDimension>> m_dims{};
    GDALExtendedDataType m_dt = GDALExtendedDataType::Create(GDT_Float64);
    std::shared_ptr<OGRSpatialReference> m_poSRS{};
    std::vector<vsi_l_offset> m_anOffsets{};
    std::vector<int> m_anSubgNums{};
    std::vector<double> m_adfTimes{};
    std::vector<std::shared_ptr<GDALAttribute>> m_attributes{};
    std::string m_osUnit{};
    std::vector<GByte> m_abyNoData{};

    GRIBArray(const std::string &osName,
              const std::shared_ptr<GRIBSharedResource> &poShared);

  protected:
    bool IRead(const GUInt64 *arrayStartIdx, const size_t *count,
               const GInt64 *arrayStep, const GPtrDiff_t *bufferStride,
               const GDALExtendedDataType &bufferDataType,
               void *pDstBuffer) const override;

  public:
    static std::shared_ptr<GRIBArray>
    Create(const std::string &osName,
           const std::shared_ptr<GRIBSharedResource> &poShared)
    {
        auto ar(std::shared_ptr<GRIBArray>(new GRIBArray(osName, poShared)));
        ar->SetSelf(ar);
        return ar;
    }

    void Init(GRIBGroup *poGroup, GRIBDataset *poDS, GRIBRasterBand *poBand,
              inventoryType *psInv);
    void ExtendTimeDim(vsi_l_offset nOffset, int subgNum, double dfValidTime);
    void Finalize(GRIBGroup *poGroup, inventoryType *psInv);

    bool IsWritable() const override
    {
        return false;
    }

    const std::string &GetFilename() const override
    {
        return m_poShared->m_osFilename;
    }

    const std::vector<std::shared_ptr<GDALDimension>> &
    GetDimensions() const override
    {
        return m_dims;
    }

    const GDALExtendedDataType &GetDataType() const override
    {
        return m_dt;
    }

    std::shared_ptr<OGRSpatialReference> GetSpatialRef() const override
    {
        return m_poSRS;
    }

    std::vector<std::shared_ptr<GDALAttribute>>
    GetAttributes(CSLConstList) const override
    {
        return m_attributes;
    }

    const std::string &GetUnit() const override
    {
        return m_osUnit;
    }

    const void *GetRawNoDataValue() const override
    {
        return m_abyNoData.empty() ? nullptr : m_abyNoData.data();
    }
};

/************************************************************************/
/*                          GetMDArrayNames()                           */
/************************************************************************/

std::vector<std::string> GRIBGroup::GetMDArrayNames(CSLConstList) const
{
    std::vector<std::string> ret;
    for (const auto &array : m_poArrays)
    {
        ret.push_back(array->GetName());
    }
    return ret;
}

/************************************************************************/
/*                            OpenMDArray()                             */
/************************************************************************/

std::shared_ptr<GDALMDArray> GRIBGroup::OpenMDArray(const std::string &osName,
                                                    CSLConstList) const
{
    for (const auto &array : m_poArrays)
    {
        if (array->GetName() == osName)
            return array;
    }
    return nullptr;
}

/************************************************************************/
/*                             GRIBArray()                              */
/************************************************************************/

GRIBArray::GRIBArray(const std::string &osName,
                     const std::shared_ptr<GRIBSharedResource> &poShared)
    : GDALAbstractMDArray("/", osName),
      GDALPamMDArray("/", osName, poShared->GetPAM()), m_poShared(poShared)
{
}

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

void GRIBArray::Init(GRIBGroup *poGroup, GRIBDataset *poDS,
                     GRIBRasterBand *poBand, inventoryType *psInv)
{
    std::shared_ptr<GDALDimension> poDimX;
    std::shared_ptr<GDALDimension> poDimY;

    GDALGeoTransform gt;
    poDS->GetGeoTransform(gt);

    for (int i = 1; i <= poGroup->m_nHorizDimCounter; i++)
    {
        std::string osXLookup("X");
        std::string osYLookup("Y");
        if (i > 1)
        {
            osXLookup += CPLSPrintf("%d", i);
            osYLookup += CPLSPrintf("%d", i);
        }
        auto oIterX = poGroup->m_oMapDims.find(osXLookup);
        auto oIterY = poGroup->m_oMapDims.find(osYLookup);
        CPLAssert(oIterX != poGroup->m_oMapDims.end());
        CPLAssert(oIterY != poGroup->m_oMapDims.end());
        if (oIterX->second->GetSize() ==
                static_cast<size_t>(poDS->GetRasterXSize()) &&
            oIterY->second->GetSize() ==
                static_cast<size_t>(poDS->GetRasterYSize()))
        {
            bool bOK = true;
            auto poVar = oIterX->second->GetIndexingVariable();
            constexpr double EPSILON = 1e-10;
            if (poVar)
            {
                GUInt64 nStart = 0;
                size_t nCount = 1;
                double dfVal = 0;
                poVar->Read(&nStart, &nCount, nullptr, nullptr, m_dt, &dfVal);
                if (std::fabs(dfVal - (gt[0] + 0.5 * gt[1])) >
                    EPSILON * std::fabs(dfVal))
                {
                    bOK = false;
                }
            }
            if (bOK)
            {
                poVar = oIterY->second->GetIndexingVariable();
                if (poVar)
                {
                    GUInt64 nStart = 0;
                    size_t nCount = 1;
                    double dfVal = 0;
                    poVar->Read(&nStart, &nCount, nullptr, nullptr, m_dt,
                                &dfVal);
                    if (std::fabs(dfVal - (gt[3] + poDS->nRasterYSize * gt[5] -
                                           0.5 * gt[5])) >
                        EPSILON * std::fabs(dfVal))
                    {
                        bOK = false;
                    }
                }
            }
            if (bOK)
            {
                poDimX = oIterX->second;
                poDimY = oIterY->second;
                break;
            }
        }
    }

    if (!poDimX || !poDimY)
    {
        poGroup->m_nHorizDimCounter++;
        {
            std::string osName("Y");
            if (poGroup->m_nHorizDimCounter >= 2)
            {
                osName = CPLSPrintf("Y%d", poGroup->m_nHorizDimCounter);
            }

            poDimY = std::make_shared<GDALDimensionWeakIndexingVar>(
                poGroup->GetFullName(), osName, GDAL_DIM_TYPE_HORIZONTAL_Y,
                std::string(), poDS->GetRasterYSize());
            poGroup->m_oMapDims[osName] = poDimY;
            poGroup->m_dims.emplace_back(poDimY);

            auto var = GDALMDArrayRegularlySpaced::Create(
                "/", poDimY->GetName(), poDimY,
                gt[3] + poDS->GetRasterYSize() * gt[5], -gt[5], 0.5);
            poDimY->SetIndexingVariable(var);
            poGroup->AddArray(var);
        }

        {
            std::string osName("X");
            if (poGroup->m_nHorizDimCounter >= 2)
            {
                osName = CPLSPrintf("X%d", poGroup->m_nHorizDimCounter);
            }

            poDimX = std::make_shared<GDALDimensionWeakIndexingVar>(
                poGroup->GetFullName(), osName, GDAL_DIM_TYPE_HORIZONTAL_X,
                std::string(), poDS->GetRasterXSize());
            poGroup->m_oMapDims[osName] = poDimX;
            poGroup->m_dims.emplace_back(poDimX);

            auto var = GDALMDArrayRegularlySpaced::Create(
                "/", poDimX->GetName(), poDimX, gt[0], gt[1], 0.5);
            poDimX->SetIndexingVariable(var);
            poGroup->AddArray(var);
        }
    }

    m_dims.emplace_back(poDimY);
    m_dims.emplace_back(poDimX);
    if (poDS->m_poSRS.get())
    {
        m_poSRS.reset(poDS->m_poSRS->Clone());
        if (poDS->m_poSRS->GetDataAxisToSRSAxisMapping() ==
            std::vector<int>{2, 1})
            m_poSRS->SetDataAxisToSRSAxisMapping({1, 2});
        else
            m_poSRS->SetDataAxisToSRSAxisMapping({2, 1});
    }

    const char *pszGribNormalizeUnits =
        CPLGetConfigOption("GRIB_NORMALIZE_UNITS", "YES");
    const bool bMetricUnits = CPLTestBool(pszGribNormalizeUnits);

    m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
        GetFullName(), "name", psInv->element));
    m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
        GetFullName(), "long_name",
        ConvertUnitInText(bMetricUnits, psInv->comment)));
    m_osUnit = ConvertUnitInText(bMetricUnits, psInv->unitName);
    if (!m_osUnit.empty() && m_osUnit[0] == '[' && m_osUnit.back() == ']')
    {
        m_osUnit = m_osUnit.substr(1, m_osUnit.size() - 2);
    }
    m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
        GetFullName(), "first_level", psInv->shortFstLevel));

    if (poBand->m_nDisciplineCode >= 0)
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeNumeric>(
            GetFullName(), "discipline_code", poBand->m_nDisciplineCode));
    }
    if (!poBand->m_osDisciplineName.empty())
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "discipline_name", poBand->m_osDisciplineName));
    }
    if (poBand->m_nCenter >= 0)
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeNumeric>(
            GetFullName(), "center_code", poBand->m_nCenter));
    }
    if (!poBand->m_osCenterName.empty())
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "center_name", poBand->m_osCenterName));
    }
    if (poBand->m_nSubCenter >= 0)
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeNumeric>(
            GetFullName(), "subcenter_code", poBand->m_nSubCenter));
    }
    if (!poBand->m_osSubCenterName.empty())
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "subcenter_name", poBand->m_osSubCenterName));
    }
    if (!poBand->m_osSignRefTimeName.empty())
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "signification_of_ref_time",
            poBand->m_osSignRefTimeName));
    }
    if (!poBand->m_osRefTime.empty())
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "reference_time_iso8601", poBand->m_osRefTime));
    }
    if (!poBand->m_osProductionStatus.empty())
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "production_status", poBand->m_osProductionStatus));
    }
    if (!poBand->m_osType.empty())
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "type", poBand->m_osType));
    }
    if (poBand->m_nPDTN >= 0)
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeNumeric>(
            GetFullName(), "product_definition_template_number",
            poBand->m_nPDTN));
    }
    if (!poBand->m_anPDSTemplateAssembledValues.empty())
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeNumeric>(
            GetFullName(), "product_definition_numbers",
            poBand->m_anPDSTemplateAssembledValues));
    }

    int bHasNoData = FALSE;
    double dfNoData = poBand->GetNoDataValue(&bHasNoData);
    if (bHasNoData)
    {
        m_abyNoData.resize(sizeof(double));
        memcpy(&m_abyNoData[0], &dfNoData, sizeof(double));
    }
}

/************************************************************************/
/*                         ExtendTimeDim()                              */
/************************************************************************/

void GRIBArray::ExtendTimeDim(vsi_l_offset nOffset, int subgNum,
                              double dfValidTime)
{
    m_anOffsets.push_back(nOffset);
    m_anSubgNums.push_back(subgNum);
    m_adfTimes.push_back(dfValidTime);
}

/************************************************************************/
/*                           Finalize()                                 */
/************************************************************************/

void GRIBArray::Finalize(GRIBGroup *poGroup, inventoryType *psInv)
{
    CPLAssert(!m_adfTimes.empty());
    CPLAssert(m_anOffsets.size() == m_adfTimes.size());

    if (m_adfTimes.size() == 1)
    {
        m_attributes.emplace_back(std::make_shared<GDALAttributeNumeric>(
            GetFullName(), "forecast_time", psInv->foreSec));
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "forecast_time_unit", "sec"));
        m_attributes.emplace_back(std::make_shared<GDALAttributeNumeric>(
            GetFullName(), "reference_time", psInv->refTime));
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "reference_time_unit", "sec UTC"));
        m_attributes.emplace_back(std::make_shared<GDALAttributeNumeric>(
            GetFullName(), "validity_time", m_adfTimes[0]));
        m_attributes.emplace_back(std::make_shared<GDALAttributeString>(
            GetFullName(), "validity_time_unit", "sec UTC"));
        return;
    }

    std::shared_ptr<GDALDimension> poDimTime;

    for (const auto &poDim : poGroup->m_dims)
    {
        if (STARTS_WITH(poDim->GetName().c_str(), "TIME") &&
            poDim->GetSize() == m_adfTimes.size())
        {
            auto poVar = poDim->GetIndexingVariable();
            if (poVar)
            {
                GUInt64 nStart = 0;
                size_t nCount = 1;
                double dfStartTime = 0;
                poVar->Read(&nStart, &nCount, nullptr, nullptr, m_dt,
                            &dfStartTime);
                if (dfStartTime == m_adfTimes[0])
                {
                    poDimTime = poDim;
                    break;
                }
            }
        }
    }

    if (!poDimTime)
    {
        std::string osName("TIME");
        int counter = 2;
        while (poGroup->m_oMapDims.find(osName) != poGroup->m_oMapDims.end())
        {
            osName = CPLSPrintf("TIME%d", counter);
            counter++;
        }

        poDimTime = std::make_shared<GDALDimensionWeakIndexingVar>(
            poGroup->GetFullName(), osName, GDAL_DIM_TYPE_TEMPORAL,
            std::string(), m_adfTimes.size());
        poGroup->m_oMapDims[osName] = poDimTime;
        poGroup->m_dims.emplace_back(poDimTime);

        auto var = poGroup->m_memRootGroup->CreateMDArray(
            poDimTime->GetName(),
            std::vector<std::shared_ptr<GDALDimension>>{poDimTime},
            GDALExtendedDataType::Create(GDT_Float64), nullptr);
        poDimTime->SetIndexingVariable(var);
        poGroup->AddArray(var);

        GUInt64 nStart = 0;
        size_t nCount = m_adfTimes.size();
        var->SetUnit("sec UTC");
        const GUInt64 anStart[] = {nStart};
        const size_t anCount[] = {nCount};
        var->Write(anStart, anCount, nullptr, nullptr, var->GetDataType(),
                   &m_adfTimes[0]);
        auto attr = var->CreateAttribute("long_name", {},
                                         GDALExtendedDataType::CreateString());
        attr->Write("validity_time");
    }

#if defined(__GNUC__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnull-dereference"
#endif
    m_dims.insert(m_dims.begin(), poDimTime);
#if defined(__GNUC__)
#pragma GCC diagnostic pop
#endif
    if (m_poSRS)
    {
        auto mapping = m_poSRS->GetDataAxisToSRSAxisMapping();
        for (auto &v : mapping)
            v += 1;
        m_poSRS->SetDataAxisToSRSAxisMapping(mapping);
    }
}

/************************************************************************/
/*                              LoadData()                              */
/************************************************************************/

const std::vector<double> &GRIBSharedResource::LoadData(vsi_l_offset nOffset,
                                                        int subgNum)
{
    if (m_nOffsetCurData == nOffset)
        return m_adfCurData;

    grib_MetaData *metadata = nullptr;
    double *data = nullptr;
    GRIBRasterBand::ReadGribData(m_fp, nOffset, subgNum, &data, &metadata);
    if (data == nullptr || metadata == nullptr)
    {
        if (metadata != nullptr)
        {
            MetaFree(metadata);
            delete metadata;
        }
        free(data);
        m_adfCurData.clear();
        return m_adfCurData;
    }
    const int nx = metadata->gds.Nx;
    const int ny = metadata->gds.Ny;
    MetaFree(metadata);
    delete metadata;
    if (nx <= 0 || ny <= 0)
    {
        free(data);
        m_adfCurData.clear();
        return m_adfCurData;
    }
    const size_t nPointCount = static_cast<size_t>(nx) * ny;
    const size_t nByteCount = nPointCount * sizeof(double);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    if (nByteCount > static_cast<size_t>(INT_MAX))
    {
        CPLError(CE_Failure, CPLE_OutOfMemory,
                 "Too large memory allocation attempt");
        free(data);
        m_adfCurData.clear();
        return m_adfCurData;
    }
#endif
    try
    {
        m_adfCurData.resize(nPointCount);
    }
    catch (const std::exception &e)
    {
        CPLError(CE_Failure, CPLE_OutOfMemory, "%s", e.what());
        free(data);
        m_adfCurData.clear();
        return m_adfCurData;
    }
    m_nOffsetCurData = nOffset;
    memcpy(&m_adfCurData[0], data, nByteCount);
    free(data);
    return m_adfCurData;
}

/************************************************************************/
/*                             IRead()                                  */
/************************************************************************/

bool GRIBArray::IRead(const GUInt64 *arrayStartIdx, const size_t *count,
                      const GInt64 *arrayStep, const GPtrDiff_t *bufferStride,
                      const GDALExtendedDataType &bufferDataType,
                      void *pDstBuffer) const
{
    const size_t nBufferDTSize(bufferDataType.GetSize());
    if (m_dims.size() == 2)
    {
        auto &vals = m_poShared->LoadData(m_anOffsets[0], m_anSubgNums[0]);
        constexpr int Y_IDX = 0;
        constexpr int X_IDX = 1;
        if (vals.empty() ||
            vals.size() != m_dims[Y_IDX]->GetSize() * m_dims[X_IDX]->GetSize())
            return false;
        const size_t nWidth(static_cast<size_t>(m_dims[X_IDX]->GetSize()));
        const bool bDirectCopy = m_dt == bufferDataType &&
                                 arrayStep[X_IDX] == 1 &&
                                 bufferStride[X_IDX] == 1;
        for (size_t j = 0; j < count[Y_IDX]; j++)
        {
            const size_t y = static_cast<size_t>(arrayStartIdx[Y_IDX] +
                                                 j * arrayStep[Y_IDX]);
            GByte *pabyDstPtr = static_cast<GByte *>(pDstBuffer) +
                                j * bufferStride[Y_IDX] * nBufferDTSize;
            const size_t x = static_cast<size_t>(arrayStartIdx[X_IDX]);
            const double *srcPtr = &vals[y * nWidth + x];
            if (bDirectCopy)
            {
                memcpy(pabyDstPtr, srcPtr, count[X_IDX] * sizeof(double));
            }
            else
            {
                const auto dstPtrInc = bufferStride[X_IDX] * nBufferDTSize;
                for (size_t i = 0; i < count[X_IDX]; i++)
                {
                    GDALExtendedDataType::CopyValue(srcPtr, m_dt, pabyDstPtr,
                                                    bufferDataType);
                    srcPtr += static_cast<std::ptrdiff_t>(arrayStep[X_IDX]);
                    pabyDstPtr += dstPtrInc;
                }
            }
        }
        return true;
    }

    constexpr int T_IDX = 0;
    constexpr int Y_IDX = 1;
    constexpr int X_IDX = 2;
    const size_t nWidth(static_cast<size_t>(m_dims[X_IDX]->GetSize()));
    const bool bDirectCopy = m_dt == bufferDataType && arrayStep[X_IDX] == 1 &&
                             bufferStride[X_IDX] == 1;
    for (size_t k = 0; k < count[T_IDX]; k++)
    {
        const size_t tIdx =
            static_cast<size_t>(arrayStartIdx[T_IDX] + k * arrayStep[T_IDX]);
        CPLAssert(tIdx < m_anOffsets.size());
        auto &vals =
            m_poShared->LoadData(m_anOffsets[tIdx], m_anSubgNums[tIdx]);
        if (vals.empty() ||
            vals.size() != m_dims[Y_IDX]->GetSize() * m_dims[X_IDX]->GetSize())
            return false;
        for (size_t j = 0; j < count[Y_IDX]; j++)
        {
            const size_t y = static_cast<size_t>(arrayStartIdx[Y_IDX] +
                                                 j * arrayStep[Y_IDX]);
            GByte *pabyDstPtr =
                static_cast<GByte *>(pDstBuffer) +
                (k * bufferStride[T_IDX] + j * bufferStride[Y_IDX]) *
                    nBufferDTSize;
            const size_t x = static_cast<size_t>(arrayStartIdx[X_IDX]);
            const double *srcPtr = &vals[y * nWidth + x];
            if (bDirectCopy)
            {
                memcpy(pabyDstPtr, srcPtr, count[X_IDX] * sizeof(double));
            }
            else
            {
                const auto dstPtrInc = bufferStride[X_IDX] * nBufferDTSize;
                for (size_t i = 0; i < count[X_IDX]; i++)
                {
                    GDALExtendedDataType::CopyValue(srcPtr, m_dt, pabyDstPtr,
                                                    bufferDataType);
                    srcPtr += static_cast<std::ptrdiff_t>(arrayStep[X_IDX]);
                    pabyDstPtr += dstPtrInc;
                }
            }
        }
    }

    return true;
}

/************************************************************************/
/*                          OpenMultiDim()                              */
/************************************************************************/

GDALDataset *GRIBDataset::OpenMultiDim(GDALOpenInfo *poOpenInfo)

{
    auto poShared = std::make_shared<GRIBSharedResource>(
        poOpenInfo->pszFilename, poOpenInfo->fpL);
    auto poRootGroup = std::make_shared<GRIBGroup>(poShared);
    poOpenInfo->fpL = nullptr;

    VSIFSeekL(poShared->m_fp, 0, SEEK_SET);

    // Contains an GRIB2 message inventory of the file.
    // We can't use the potential .idx file
    auto pInventories = std::make_unique<InventoryWrapperGrib>(poShared->m_fp);

    if (pInventories->result() <= 0)
    {
        char *errMsg = errSprintf(nullptr);
        if (errMsg != nullptr)
            CPLDebug("GRIB", "%s", errMsg);
        free(errMsg);

        CPLError(CE_Failure, CPLE_OpenFailed,
                 "%s is a grib file, "
                 "but no raster dataset was successfully identified.",
                 poOpenInfo->pszFilename);
        return nullptr;
    }

    // Create band objects.
    GRIBDataset *poDS = new GRIBDataset();
    poDS->fp = poShared->m_fp;

    std::shared_ptr<GRIBArray> poArray;
    std::set<std::string> oSetArrayNames;
    std::string osElement;
    std::string osShortFstLevel;
    double dfRefTime = 0;
    double dfForecastTime = 0;
    for (uInt4 i = 0; i < pInventories->length(); ++i)
    {
        inventoryType *psInv = pInventories->get(i);
        uInt4 bandNr = i + 1;
        assert(bandNr <= 65536);

        // GRIB messages can be preceded by "garbage". GRIB2Inventory()
        // does not return the offset to the real start of the message
        GByte abyHeader[1024 + 1];
        VSIFSeekL(poShared->m_fp, psInv->start, SEEK_SET);
        size_t nRead =
            VSIFReadL(abyHeader, 1, sizeof(abyHeader) - 1, poShared->m_fp);
        abyHeader[nRead] = 0;
        // Find the real offset of the fist message
        const char *pasHeader = reinterpret_cast<char *>(abyHeader);
        int nOffsetFirstMessage = 0;
        for (int j = 0; j < poOpenInfo->nHeaderBytes - 3; j++)
        {
            if (STARTS_WITH_CI(pasHeader + j, "GRIB")
#ifdef ENABLE_TDLP
                || STARTS_WITH_CI(pasHeader + j, "TDLP")
#endif
            )
            {
                nOffsetFirstMessage = j;
                break;
            }
        }
        psInv->start += nOffsetFirstMessage;

        if (poArray == nullptr || osElement != psInv->element ||
            osShortFstLevel != psInv->shortFstLevel ||
            !((dfRefTime == psInv->refTime &&
               dfForecastTime != psInv->foreSec) ||
              (dfRefTime != psInv->refTime &&
               dfForecastTime == psInv->foreSec)))
        {
            if (poArray)
            {
                poArray->Finalize(poRootGroup.get(), pInventories->get(i - 1));
                poRootGroup->AddArray(poArray);
            }

            grib_MetaData *metaData = nullptr;
            GRIBRasterBand::ReadGribData(poShared->m_fp, psInv->start,
                                         psInv->subgNum, nullptr, &metaData);
            if (metaData == nullptr || metaData->gds.Nx < 1 ||
                metaData->gds.Ny < 1)
            {
                CPLError(CE_Failure, CPLE_OpenFailed,
                         "%s is a grib file, "
                         "but no raster dataset was successfully identified.",
                         poOpenInfo->pszFilename);

                if (metaData != nullptr)
                {
                    MetaFree(metaData);
                    delete metaData;
                }
                poDS->fp = nullptr;
                CPLReleaseMutex(hGRIBMutex);
                delete poDS;
                CPLAcquireMutex(hGRIBMutex, 1000.0);
                return nullptr;
            }
            psInv->GribVersion = metaData->GribVersion;

            // Set the DataSet's x,y size, georeference and projection from
            // the first GRIB band.
            poDS->SetGribMetaData(metaData);

            GRIBRasterBand gribBand(poDS, bandNr, psInv);
            if (psInv->GribVersion == 2)
                gribBand.FindPDSTemplateGRIB2();
            osElement = psInv->element;
            osShortFstLevel = psInv->shortFstLevel;
            dfRefTime = psInv->refTime;
            dfForecastTime = psInv->foreSec;

            std::string osRadix(osElement + '_' + osShortFstLevel);
            std::string osName(osRadix);
            int nCounter = 2;
            while (oSetArrayNames.find(osName) != oSetArrayNames.end())
            {
                osName = osRadix + CPLSPrintf("_%d", nCounter);
                nCounter++;
            }
            oSetArrayNames.insert(osName);
            poArray = GRIBArray::Create(osName, poShared);
            poArray->Init(poRootGroup.get(), poDS, &gribBand, psInv);
            poArray->ExtendTimeDim(psInv->start, psInv->subgNum,
                                   psInv->validTime);

            MetaFree(metaData);
            delete metaData;
        }
        else
        {
            poArray->ExtendTimeDim(psInv->start, psInv->subgNum,
                                   psInv->validTime);
        }
    }

    if (poArray)
    {
        poArray->Finalize(poRootGroup.get(),
                          pInventories->get(pInventories->length() - 1));
        poRootGroup->AddArray(poArray);
    }

    poDS->fp = nullptr;
    poDS->m_poRootGroup = poRootGroup;

    poDS->SetDescription(poOpenInfo->pszFilename);

    // Release hGRIBMutex otherwise we'll deadlock with GDALDataset own
    // hGRIBMutex.
    CPLReleaseMutex(hGRIBMutex);
    poDS->TryLoadXML();
    CPLAcquireMutex(hGRIBMutex, 1000.0);

    return poDS;
}

/************************************************************************/
/*                            SetMetadata()                             */
/************************************************************************/

void GRIBDataset::SetGribMetaData(grib_MetaData *meta)
{
    nRasterXSize = meta->gds.Nx;
    nRasterYSize = meta->gds.Ny;

    // Image projection.
    OGRSpatialReference oSRS;
    oSRS.SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);

    switch (meta->gds.projType)
    {
        case GS3_LATLON:
        case GS3_GAUSSIAN_LATLON:
            // No projection, only latlon system (geographic).
            break;
        case GS3_ROTATED_LATLON:
            // will apply pole rotation afterwards
            break;
        case GS3_MERCATOR:
            if (meta->gds.orientLon == 0.0)
            {
                if (meta->gds.meshLat == 0.0)
                    oSRS.SetMercator(0.0, 0.0, 1.0, 0.0, 0.0);
                else
                    oSRS.SetMercator2SP(meta->gds.meshLat, 0.0, 0.0, 0.0, 0.0);
            }
            else
            {
                CPLError(CE_Warning, CPLE_NotSupported,
                         "Orientation of the grid != 0 not supported");
                return;
            }
            break;
        case GS3_TRANSVERSE_MERCATOR:
            oSRS.SetTM(meta->gds.latitude_of_origin,
                       Lon360to180(meta->gds.central_meridian),
                       std::abs(meta->gds.scaleLat1 - 0.9996) < 1e-8
                           ? 0.9996
                           : meta->gds.scaleLat1,
                       meta->gds.x0, meta->gds.y0);
            break;
        case GS3_POLAR:
            oSRS.SetPS(meta->gds.meshLat, meta->gds.orientLon, 1.0, 0.0, 0.0);
            break;
        case GS3_LAMBERT:
            oSRS.SetLCC(meta->gds.scaleLat1, meta->gds.scaleLat2,
                        meta->gds.meshLat, Lon360to180(meta->gds.orientLon),
                        0.0, 0.0);
            break;
        case GS3_ALBERS_EQUAL_AREA:
            oSRS.SetACEA(meta->gds.scaleLat1, meta->gds.scaleLat2,
                         meta->gds.meshLat, Lon360to180(meta->gds.orientLon),
                         0.0, 0.0);
            break;

        case GS3_ORTHOGRAPHIC:

            // oSRS.SetOrthographic( 0.0, meta->gds.orientLon,
            //                       meta->gds.lon2, meta->gds.lat2);

            // oSRS.SetGEOS( meta->gds.orientLon, meta->gds.stretchFactor,
            //               meta->gds.lon2, meta->gds.lat2);

            // TODO: Hardcoded for now. How to parse the meta->gds section?
            oSRS.SetGEOS(0, 35785831, 0, 0);
            break;
        case GS3_LAMBERT_AZIMUTHAL:
            oSRS.SetLAEA(meta->gds.meshLat, Lon360to180(meta->gds.orientLon),
                         0.0, 0.0);
            break;

        case GS3_EQUATOR_EQUIDIST:
            break;
        case GS3_AZIMUTH_RANGE:
            break;
    }

    if (oSRS.IsProjected())
    {
        oSRS.SetLinearUnits("Metre", 1.0);
    }

    const bool bHaveEarthModel =
        meta->gds.majEarth > 0.0 && meta->gds.minEarth > 0.0;
    // In meters.
    const double a = bHaveEarthModel
                         ? meta->gds.majEarth * 1.0e3
                         : CPLAtof(CPLGetConfigOption("GRIB_DEFAULT_SEMI_MAJOR",
                                                      "6377563.396"));
    const double b =
        bHaveEarthModel
            ? meta->gds.minEarth * 1.0e3
            : (meta->gds.f_sphere
                   ? a
                   : CPLAtof(CPLGetConfigOption("GRIB_DEFAULT_SEMI_MINOR",
                                                "6356256.910")));
    if (meta->gds.majEarth == 0 || meta->gds.minEarth == 0)
    {
        CPLDebug("GRIB", "No earth model. Assuming a=%f and b=%f", a, b);
    }
    else if (meta->gds.majEarth < 0 || meta->gds.minEarth < 0)
    {
        const char *pszUseDefaultSpheroid =
            CPLGetConfigOption("GRIB_USE_DEFAULT_SPHEROID", nullptr);
        if (!pszUseDefaultSpheroid)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "The GRIB file contains invalid values for the spheroid. "
                     "You may set the GRIB_USE_DEFAULT_SPHEROID configuration "
                     "option to YES to use a default spheroid with "
                     "a=%f and b=%f",
                     a, b);
            return;
        }
        else if (!CPLTestBool(pszUseDefaultSpheroid))
        {
            return;
        }
        CPLDebug("GRIB", "Invalid earth model. Assuming a=%f and b=%f", a, b);
    }

    if (meta->gds.f_sphere || (a == b))
    {
        oSRS.SetGeogCS("Coordinate System imported from GRIB file", nullptr,
                       "Sphere", a, 0.0);
    }
    else
    {
        const double fInv = a / (a - b);
        if (std::abs(a - 6378137.0) < 0.01 &&
            std::abs(fInv - 298.257223563) < 1e-9)  // WGS84
        {
            if (meta->gds.projType == GS3_LATLON)
                oSRS.SetFromUserInput(SRS_WKT_WGS84_LAT_LONG);
            else
            {
                oSRS.SetGeogCS("Coordinate System imported from GRIB file",
                               "WGS_1984", "WGS 84", 6378137., 298.257223563);
            }
        }
        else if (std::abs(a - 6378137.0) < 0.01 &&
                 std::abs(fInv - 298.257222101) < 1e-9)  // GRS80
        {
            oSRS.SetGeogCS("Coordinate System imported from GRIB file", nullptr,
                           "GRS80", 6378137., 298.257222101);
        }
        else
        {
            oSRS.SetGeogCS("Coordinate System imported from GRIB file", nullptr,
                           "Spheroid imported from GRIB file", a, fInv);
        }
    }

    if (meta->gds.projType == GS3_ROTATED_LATLON)
    {
        oSRS.SetDerivedGeogCRSWithPoleRotationGRIBConvention(
            oSRS.GetName(), meta->gds.southLat, Lon360to180(meta->gds.southLon),
            meta->gds.angleRotate);
    }

    OGRSpatialReference oLL;  // Construct the "geographic" part of oSRS.
    oLL.SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);
    oLL.CopyGeogCSFrom(&oSRS);

    double rMinX = 0.0;
    double rMaxY = 0.0;
    double rPixelSizeX = 0.0;
    double rPixelSizeY = 0.0;
    bool bError = false;
    if (meta->gds.projType == GS3_ORTHOGRAPHIC)
    {
        // This is what should work, but it doesn't. Dx seems to have an
        // inverse relation with pixel size.
        // rMinX = -meta->gds.Dx * (meta->gds.Nx / 2);
        // rMaxY = meta->gds.Dy * (meta->gds.Ny / 2);
        // Hardcoded for now, assumption: GEOS projection, full disc (like MSG).
        const double geosExtentInMeters = 11137496.552;
        rMinX = -(geosExtentInMeters / 2);
        rMaxY = geosExtentInMeters / 2;
        rPixelSizeX = geosExtentInMeters / meta->gds.Nx;
        rPixelSizeY = geosExtentInMeters / meta->gds.Ny;
    }
    else if (meta->gds.projType == GS3_TRANSVERSE_MERCATOR)
    {
        rMinX = meta->gds.x1;
        rMaxY = meta->gds.y2;
        rPixelSizeX = meta->gds.Dx;
        rPixelSizeY = meta->gds.Dy;
    }
    else if (oSRS.IsProjected() && meta->gds.projType != GS3_ROTATED_LATLON)
    {
        // Longitude in degrees, to be transformed to meters (or degrees in
        // case of latlon).
        rMinX = Lon360to180(meta->gds.lon1);
        // Latitude in degrees, to be transformed to meters.
        double dfGridOriY = meta->gds.lat1;

        if (m_poSRS == nullptr || m_poLL == nullptr ||
            !m_poSRS->IsSame(&oSRS) || !m_poLL->IsSame(&oLL))
        {
            m_poCT = std::unique_ptr<OGRCoordinateTransformation>(
                OGRCreateCoordinateTransformation(&(oLL), &(oSRS)));
        }

        // Transform it to meters.
        if ((m_poCT != nullptr) && m_poCT->Transform(1, &rMinX, &dfGridOriY))
        {
            if (meta->gds.scan == GRIB2BIT_2)  // Y is minY, GDAL wants maxY.
            {
                const char *pszConfigOpt = CPLGetConfigOption(
                    "GRIB_LATITUDE_OF_FIRST_GRID_POINT_IS_SOUTHERN_MOST",
                    nullptr);
                bool bLatOfFirstPointIsSouthernMost =
                    !pszConfigOpt || CPLTestBool(pszConfigOpt);

                // Hack for a file called MANAL_2023030103.grb2 that
                // uses LCC and has Latitude of false origin = 30
                // Longitude of false origin = 140
                // Latitude of 1st standard parallel = 60
                // Latitude of 2nd standard parallel = 30
                // but whose (meta->gds.lon1, meta->gds.lat1) qualifies the
                // northern-most point of the grid and not the bottom-most one
                // as it should given the scan == GRIB2BIT_2
                if (!pszConfigOpt && meta->gds.projType == GS3_LAMBERT &&
                    std::fabs(meta->gds.scaleLat1 - 60) <= 1e-8 &&
                    std::fabs(meta->gds.scaleLat2 - 30) <= 1e-8 &&
                    std::fabs(meta->gds.meshLat - 30) <= 1e-8 &&
                    std::fabs(Lon360to180(meta->gds.orientLon) - 140) <= 1e-8)
                {
                    double dfXCenterProj = Lon360to180(meta->gds.orientLon);
                    double dfYCenterProj = meta->gds.meshLat;
                    if (m_poCT->Transform(1, &dfXCenterProj, &dfYCenterProj))
                    {
                        double dfXCenterGridNominal =
                            rMinX + nRasterXSize * meta->gds.Dx / 2;
                        double dfYCenterGridNominal =
                            dfGridOriY + nRasterYSize * meta->gds.Dy / 2;
                        double dfXCenterGridBuggy = dfXCenterGridNominal;
                        double dfYCenterGridBuggy =
                            dfGridOriY - nRasterYSize * meta->gds.Dy / 2;
                        const auto SQR = [](double x) { return x * x; };
                        if (SQR(dfXCenterGridBuggy - dfXCenterProj) +
                                SQR(dfYCenterGridBuggy - dfYCenterProj) <
                            SQR(10) *
                                (SQR(dfXCenterGridNominal - dfXCenterProj) +
                                 SQR(dfYCenterGridNominal - dfYCenterProj)))
                        {
                            CPLError(
                                CE_Warning, CPLE_AppDefined,
                                "Likely buggy grid registration for GRIB2 "
                                "product: heuristics shows that the "
                                "latitudeOfFirstGridPoint is likely to qualify "
                                "the latitude of the northern-most grid point "
                                "instead of the southern-most grid point as "
                                "expected. Please report to data producer. "
                                "This heuristics can be disabled by setting "
                                "the "
                                "GRIB_LATITUDE_OF_FIRST_GRID_POINT_IS_SOUTHERN_"
                                "MOST configuration option to YES.");
                            bLatOfFirstPointIsSouthernMost = false;
                        }
                    }
                }
                if (bLatOfFirstPointIsSouthernMost)
                {
                    // -1 because we GDAL needs the coordinates of the centre of
                    // the pixel.
                    rMaxY = dfGridOriY + (meta->gds.Ny - 1) * meta->gds.Dy;
                }
                else
                {
                    rMaxY = dfGridOriY;
                }
            }
            else
            {
                rMaxY = dfGridOriY;
            }
            rPixelSizeX = meta->gds.Dx;
            rPixelSizeY = meta->gds.Dy;
        }
        else
        {
            rMinX = 0.0;
            // rMaxY = 0.0;

            rPixelSizeX = 1.0;
            rPixelSizeY = -1.0;

            bError = true;
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Unable to perform coordinate transformations, so the "
                     "correct projected geotransform could not be deduced "
                     "from the lat/long control points.  "
                     "Defaulting to ungeoreferenced.");
        }
    }
    else
    {
        // Longitude in degrees, to be transformed to meters (or degrees in
        // case of latlon).
        rMinX = meta->gds.lon1;
        // Latitude in degrees, to be transformed to meters.
        rMaxY = meta->gds.lat1;

        double rMinY = meta->gds.lat2;
        double rMaxX = meta->gds.lon2;
        if (meta->gds.lat2 > rMaxY)
        {
            rMaxY = meta->gds.lat2;
            rMinY = meta->gds.lat1;
        }

        if (meta->gds.Nx == 1)
            rPixelSizeX = meta->gds.Dx;
        else if (meta->gds.lon1 > meta->gds.lon2)
            rPixelSizeX = (360.0 - (meta->gds.lon1 - meta->gds.lon2)) /
                          (meta->gds.Nx - 1);
        else
            rPixelSizeX =
                (meta->gds.lon2 - meta->gds.lon1) / (meta->gds.Nx - 1);

        if (meta->gds.Ny == 1)
            rPixelSizeY = meta->gds.Dy;
        else
            rPixelSizeY = (rMaxY - rMinY) / (meta->gds.Ny - 1);

        // Do some sanity checks for cases that can't be handled by the above
        // pixel size corrections. GRIB1 has a minimum precision of 0.001
        // for latitudes and longitudes, so we'll allow a bit higher than that.
        if (rPixelSizeX < 0 || fabs(rPixelSizeX - meta->gds.Dx) > 0.002)
            rPixelSizeX = meta->gds.Dx;

        if (rPixelSizeY < 0 || fabs(rPixelSizeY - meta->gds.Dy) > 0.002)
            rPixelSizeY = meta->gds.Dy;

        // GRIB2 files have longitudes in the [0-360] range
        // Shift them to the traditional [-180,180] longitude range
        // See https://github.com/OSGeo/gdal/issues/4524
        if ((rMinX + rPixelSizeX >= 180 || rMaxX - rPixelSizeX >= 180) &&
            CPLTestBool(
                CPLGetConfigOption("GRIB_ADJUST_LONGITUDE_RANGE", "YES")))
        {
            if (rPixelSizeX * nRasterXSize > 360 + rPixelSizeX / 4)
                CPLDebug("GRIB", "Cannot properly handle GRIB2 files with "
                                 "overlaps and 0-360 longitudes");
            else if (rMinX == 180)
            {
                // Case of https://github.com/OSGeo/gdal/issues/10655
                CPLDebug("GRIB", "Shifting longitudes from %lf:%lf to %lf:%lf",
                         rMinX, rMaxX, -180.0, Lon360to180(rMaxX));
                rMinX = -180;
            }
            else if (fabs(360 - rPixelSizeX * nRasterXSize) < rPixelSizeX / 4 &&
                     rMinX <= 180 && meta->gds.projType == GS3_LATLON)
            {
                // Find the first row number east of the antimeridian
                const int nSplitAndSwapColumnCandidate =
                    static_cast<int>(ceil((180 - rMinX) / rPixelSizeX));
                if (nSplitAndSwapColumnCandidate < nRasterXSize)
                {
                    nSplitAndSwapColumn = nSplitAndSwapColumnCandidate;
                    CPLDebug("GRIB",
                             "Rewrapping around the antimeridian at column %d",
                             nSplitAndSwapColumn);
                    rMinX = -180;
                }
            }
            else if (Lon360to180(rMinX) > Lon360to180(rMaxX))
            {
                CPLDebug("GRIB", "GRIB with 0-360 longitudes spanning across "
                                 "the antimeridian");
                rMinX = Lon360to180(rMinX);
            }
            else
            {
                CPLDebug("GRIB", "Shifting longitudes from %lf:%lf to %lf:%lf",
                         rMinX, rMaxX, Lon360to180(rMinX), Lon360to180(rMaxX));
                rMinX = Lon360to180(rMinX);
            }
        }
    }

    // https://gdal.org/user/raster_data_model.html :
    //   we need the top left corner of the top left pixel.
    //   At the moment we have the center of the pixel.
    rMinX -= rPixelSizeX / 2;
    rMaxY += rPixelSizeY / 2;

    m_gt[0] = rMinX;
    m_gt[3] = rMaxY;
    m_gt[1] = rPixelSizeX;
    m_gt[5] = -rPixelSizeY;

    if (bError)
        m_poSRS.reset();
    else
        m_poSRS.reset(oSRS.Clone());
    m_poLL = std::unique_ptr<OGRSpatialReference>(oLL.Clone());
}

/************************************************************************/
/*                       GDALDeregister_GRIB()                          */
/************************************************************************/

static void GDALDeregister_GRIB(GDALDriver *)
{
    if (hGRIBMutex != nullptr)
    {
        MetanameCleanup();
        CPLDestroyMutex(hGRIBMutex);
        hGRIBMutex = nullptr;
    }
}

/************************************************************************/
/*                          GDALGRIBDriver                              */
/************************************************************************/

class GDALGRIBDriver : public GDALDriver
{
    std::mutex m_oMutex{};
    bool m_bHasFullInitMetadata = false;
    void InitializeMetadata();

  public:
    GDALGRIBDriver() = default;

    char **GetMetadata(const char *pszDomain = "") override;
    const char *GetMetadataItem(const char *pszName,
                                const char *pszDomain) override;
};

/************************************************************************/
/*                         InitializeMetadata()                         */
/************************************************************************/

void GDALGRIBDriver::InitializeMetadata()
{
    {
        // Defer until necessary the setting of the CreationOptionList
        // to let a chance to JPEG2000 drivers to have been loaded.
        if (!m_bHasFullInitMetadata)
        {
            m_bHasFullInitMetadata = true;

            std::vector<CPLString> aosJ2KDrivers;
            for (size_t i = 0; i < CPL_ARRAYSIZE(apszJ2KDrivers); i++)
            {
                if (GDALGetDriverByName(apszJ2KDrivers[i]) != nullptr)
                {
                    aosJ2KDrivers.push_back(apszJ2KDrivers[i]);
                }
            }

            CPLString osCreationOptionList(
                "<CreationOptionList>"
                "   <Option name='DATA_ENCODING' type='string-select' "
                "default='AUTO' "
                "description='How data is encoded internally'>"
                "       <Value>AUTO</Value>"
                "       <Value>SIMPLE_PACKING</Value>"
                "       <Value>COMPLEX_PACKING</Value>"
                "       <Value>IEEE_FLOATING_POINT</Value>");
            if (GDALGetDriverByName("PNG") != nullptr)
                osCreationOptionList += "       <Value>PNG</Value>";
            if (!aosJ2KDrivers.empty())
                osCreationOptionList += "       <Value>JPEG2000</Value>";
            osCreationOptionList +=
                "   </Option>"
                "   <Option name='NBITS' type='int' default='0' "
                "description='Number of bits per value'/>"
                "   <Option name='DECIMAL_SCALE_FACTOR' type='int' default='0' "
                "description='Value such that raw values are multiplied by "
                "10^DECIMAL_SCALE_FACTOR before integer encoding'/>"
                "   <Option name='SPATIAL_DIFFERENCING_ORDER' type='int' "
                "default='0' "
                "description='Order of spatial difference' min='0' max='2'/>";
            if (!aosJ2KDrivers.empty())
            {
                osCreationOptionList +=
                    "   <Option name='COMPRESSION_RATIO' type='int' "
                    "default='1' min='1' max='100' "
                    "description='N:1 target compression ratio for JPEG2000'/>"
                    "   <Option name='JPEG2000_DRIVER' type='string-select' "
                    "description='Explicitly select a JPEG2000 driver'>";
                for (size_t i = 0; i < aosJ2KDrivers.size(); i++)
                {
                    osCreationOptionList +=
                        "       <Value>" + aosJ2KDrivers[i] + "</Value>";
                }
                osCreationOptionList += "   </Option>";
            }
            osCreationOptionList +=
                "   <Option name='DISCIPLINE' type='int' "
                "description='Discipline of the processed data'/>"
                "   <Option name='IDS' type='string' "
                "description='String equivalent to the GRIB_IDS metadata "
                "item'/>"
                "   <Option name='IDS_CENTER' type='int' "
                "description='Originating/generating center'/>"
                "   <Option name='IDS_SUBCENTER' type='int' "
                "description='Originating/generating subcenter'/>"
                "   <Option name='IDS_MASTER_TABLE' type='int' "
                "description='GRIB master tables version number'/>"
                "   <Option name='IDS_SIGNF_REF_TIME' type='int' "
                "description='Significance of Reference Time'/>"
                "   <Option name='IDS_REF_TIME' type='string' "
                "description='Reference time as YYYY-MM-DDTHH:MM:SSZ'/>"
                "   <Option name='IDS_PROD_STATUS' type='int' "
                "description='Production Status of Processed data'/>"
                "   <Option name='IDS_TYPE' type='int' "
                "description='Type of processed data'/>"
                "   <Option name='PDS_PDTN' type='int' "
                "description='Product Definition Template Number'/>"
                "   <Option name='PDS_TEMPLATE_NUMBERS' type='string' "
                "description='Product definition template raw numbers'/>"
                "   <Option name='PDS_TEMPLATE_ASSEMBLED_VALUES' type='string' "
                "description='Product definition template assembled values'/>"
                "   <Option name='INPUT_UNIT' type='string' "
                "description='Unit of input values. Only for temperatures. C "
                "or K'/>"
                "   <Option name='BAND_*' type='string' "
                "description='Override options at band level'/>"
                "</CreationOptionList>";

            SetMetadataItem(GDAL_DMD_CREATIONOPTIONLIST, osCreationOptionList);
        }
    }
}

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

char **GDALGRIBDriver::GetMetadata(const char *pszDomain)
{
    std::lock_guard oLock(m_oMutex);
    if (pszDomain == nullptr || EQUAL(pszDomain, ""))
    {
        InitializeMetadata();
    }
    return GDALDriver::GetMetadata(pszDomain);
}

/************************************************************************/
/*                          GetMetadataItem()                           */
/************************************************************************/

const char *GDALGRIBDriver::GetMetadataItem(const char *pszName,
                                            const char *pszDomain)
{
    std::lock_guard oLock(m_oMutex);
    if (pszDomain == nullptr || EQUAL(pszDomain, ""))
    {
        // Defer until necessary the setting of the CreationOptionList
        // to let a chance to JPEG2000 drivers to have been loaded.
        if (EQUAL(pszName, GDAL_DMD_CREATIONOPTIONLIST))
            InitializeMetadata();
    }
    return GDALDriver::GetMetadataItem(pszName, pszDomain);
}

/************************************************************************/
/*                         GDALRegister_GRIB()                          */
/************************************************************************/

void GDALRegister_GRIB()

{
    if (GDALGetDriverByName(DRIVER_NAME) != nullptr)
        return;

    GDALDriver *poDriver = new GDALGRIBDriver();
    GRIBDriverSetCommonMetadata(poDriver);

    poDriver->pfnOpen = GRIBDataset::Open;
    poDriver->pfnCreateCopy = GRIBDataset::CreateCopy;
    poDriver->pfnUnloadDriver = GDALDeregister_GRIB;

#ifdef USE_AEC
    poDriver->SetMetadataItem("HAVE_AEC", "YES");
#endif

    GetGDALDriverManager()->RegisterDriver(poDriver);
}

Coverage Report

Created: 2025-07-23 09:13