/******************************************************************************
 *
 * Purpose:  ADRG reader
 * Author:   Even Rouault, even.rouault at mines-paris.org
 *
 ******************************************************************************
 * Copyright (c) 2007-2013, Even Rouault <even dot rouault at mines-paris dot org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "cpl_string.h"
#include "gdal_pam.h"
#include "gdal_frmts.h"
#include "iso8211.h"
#include "ogr_spatialref.h"

#include <limits>
#include <new>

CPL_CVSID("$Id: adrgdataset.cpp 0fa6cd3bb91725d37713ddac2fea45595bdfc567 2019-08-12 01:35:29 +0200 Even Rouault $")

#define N_ELEMENTS(x)  (sizeof(x)/sizeof(x[0]))

#define DIGIT_ZERO '0'

class ADRGDataset : public GDALPamDataset
{
    friend class ADRGRasterBand;

    CPLString    osGENFileName;
    CPLString    osIMGFileName;
    CPLString    osSRS;

    VSILFILE*        fdIMG;
    int*         TILEINDEX;
    int          offsetInIMG;
    int          NFC;
    int          NFL;
    double       LSO;
    double       PSO;
    int          ARV;
    int          BRV;

    char**       papszSubDatasets;

    ADRGDataset* poOverviewDS;

    /* For creation */
    int          bCreation;
    VSILFILE*        fdGEN;
    VSILFILE*        fdTHF;
    int          bGeoTransformValid;
    double       adfGeoTransform[6];
    int          nNextAvailableBlock;
    CPLString    osBaseFileName;

    static char** GetGENListFromTHF(const char* pszFileName);
    static char** GetIMGListFromGEN(const char* pszFileName, int* pnRecordIndex = nullptr);
    static ADRGDataset* OpenDataset(const char* pszGENFileName, const char* pszIMGFileName, DDFRecord* record = nullptr);
    static DDFRecord*  FindRecordInGENForIMG(DDFModule& module,
                                             const char* pszGENFileName, const char* pszIMGFileName);

  public:
    ADRGDataset();
    ~ADRGDataset() override;

    const char *GetProjectionRef(void) override;
    CPLErr GetGeoTransform( double * padfGeoTransform ) override;
    CPLErr SetGeoTransform( double * padfGeoTransform ) override;

    char **GetMetadataDomainList() override;
    char **GetMetadata( const char * pszDomain = "" ) override;

    char **GetFileList() override;

    void AddSubDataset( const char* pszGENFileName,
                        const char* pszIMGFileName );

    static GDALDataset *Open( GDALOpenInfo * );
    static GDALDataset *Create(const char* pszFilename, int nXSize, int nYSize,
                               int nBands, GDALDataType eType, char **papszOptions);

    static double GetLongitudeFromString(const char* str);
    static double GetLatitudeFromString(const char* str);

    void WriteGENFile();
    void WriteTHFFile();
};

/************************************************************************/
/* ==================================================================== */
/*                            ADRGRasterBand                             */
/* ==================================================================== */
/************************************************************************/

class ADRGRasterBand : public GDALPamRasterBand
{
    friend class ADRGDataset;

  public:
    ADRGRasterBand( ADRGDataset *, int );

    GDALColorInterp GetColorInterpretation() override;
    CPLErr IReadBlock( int, int, void * ) override;
    CPLErr IWriteBlock( int, int, void * ) override;

    double GetNoDataValue( int *pbSuccess = nullptr ) override;

    // virtual int GetOverviewCount();
    // virtual GDALRasterBand* GetOverview(int i);
};

/************************************************************************/
/*                           ADRGRasterBand()                            */
/************************************************************************/

ADRGRasterBand::ADRGRasterBand( ADRGDataset *poDSIn, int nBandIn )

{
    poDS = poDSIn;
    nBand = nBandIn;

    eDataType = GDT_Byte;

    nBlockXSize = 128;
    nBlockYSize = 128;
}

#if 0

/* We have a problem with the overview. Its geo bounding box doesn't match */
/* exactly the one of the main image. We should handle the shift between */
/* the two top level corners... */

/************************************************************************/
/*                          GetOverviewCount()                          */
/************************************************************************/

int ADRGRasterBand::GetOverviewCount()

{
    ADRGDataset* poDS = (ADRGDataset*)this->poDS;
    if( poDS->poOverviewDS )
        return 1;

    return GDALRasterBand::GetOverviewCount();
}

/************************************************************************/
/*                            GetOverview()                             */
/************************************************************************/

GDALRasterBand *ADRGRasterBand::GetOverview( int i )

{
    ADRGDataset* poDS = (ADRGDataset*)this->poDS;
    if( poDS->poOverviewDS )
    {
        if( i < 0 || i >= 1 )
            return NULL;

        return poDS->poOverviewDS->GetRasterBand(nBand);
    }

    return GDALRasterBand::GetOverview( i );
}
#endif

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

double ADRGRasterBand::GetNoDataValue( int *pbSuccess )
{
    if( pbSuccess )
        *pbSuccess = TRUE;

    return 0.0;
}

/************************************************************************/
/*                       GetColorInterpretation()                       */
/************************************************************************/

GDALColorInterp ADRGRasterBand::GetColorInterpretation()

{
    if( nBand == 1 )
        return GCI_RedBand;

    else if( nBand == 2 )
        return GCI_GreenBand;

    return GCI_BlueBand;
}

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

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

{
    ADRGDataset* l_poDS = (ADRGDataset*)this->poDS;
    int nBlock = nBlockYOff * l_poDS->NFC + nBlockXOff;
    if( nBlockXOff >= l_poDS->NFC || nBlockYOff >= l_poDS->NFL )
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "nBlockXOff=%d, NFC=%d, nBlockYOff=%d, NFL=%d",
                 nBlockXOff, l_poDS->NFC, nBlockYOff, l_poDS->NFL);
        return CE_Failure;
    }
    CPLDebug("ADRG", "(%d,%d) -> nBlock = %d", nBlockXOff, nBlockYOff, nBlock);

    vsi_l_offset offset;
    if( l_poDS->TILEINDEX )
    {
        if( l_poDS->TILEINDEX[nBlock] <= 0 )
        {
            memset(pImage, 0, 128 * 128);
            return CE_None;
        }
        offset = l_poDS->offsetInIMG + static_cast<vsi_l_offset>(l_poDS->TILEINDEX[nBlock] - 1) * 128 * 128 * 3 + (nBand - 1) * 128 * 128;
    }
    else
        offset = l_poDS->offsetInIMG + static_cast<vsi_l_offset>(nBlock) * 128 * 128 * 3 + (nBand - 1) * 128 * 128;

    if( VSIFSeekL(l_poDS->fdIMG, offset, SEEK_SET) != 0 )
    {
        CPLError(CE_Failure, CPLE_FileIO, "Cannot seek to offset " CPL_FRMT_GUIB, offset);
        return CE_Failure;
    }
    if( VSIFReadL(pImage, 1, 128 * 128, l_poDS->fdIMG) != 128 * 128 )
    {
        CPLError(CE_Failure, CPLE_FileIO, "Cannot read data at offset " CPL_FRMT_GUIB, offset);
        return CE_Failure;
    }

    return CE_None;
}

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

CPLErr ADRGRasterBand::IWriteBlock( int nBlockXOff, int nBlockYOff,
                                    void * pImage )

{
    ADRGDataset* l_poDS = (ADRGDataset*)this->poDS;
    int nBlock = nBlockYOff * l_poDS->NFC + nBlockXOff;
    if( l_poDS->eAccess != GA_Update )
    {
        return CE_Failure;
    }
    if( nBlockXOff >= l_poDS->NFC || nBlockYOff >= l_poDS->NFL )
    {
        CPLError(CE_Failure, CPLE_AppDefined, "nBlockXOff=%d, NFC=%d, nBlockYOff=%d, NFL=%d",
                 nBlockXOff, l_poDS->NFC, nBlockYOff, l_poDS->NFL);
        return CE_Failure;
    }
    CPLDebug("ADRG", "(%d,%d) -> nBlock = %d", nBlockXOff, nBlockYOff, nBlock);

    if( l_poDS->TILEINDEX[nBlock] == 0 )
    {
        unsigned int i;
        int* pi = (int*)pImage;
        for(i=0;i<128*128 / sizeof(int);i++)
        {
            if( pi[i] )
                break;
        }
        if( i == 128*128 / sizeof(int) )
        {
            return CE_None;
        }

        l_poDS->TILEINDEX[nBlock] = l_poDS->nNextAvailableBlock ++;
    }

    const int offset =
        l_poDS->offsetInIMG +
        (l_poDS->TILEINDEX[nBlock] - 1) * 128 * 128 * 3 +
        (nBand - 1) * 128 * 128;

    if( VSIFSeekL(l_poDS->fdIMG, offset, SEEK_SET) != 0 )
    {
        CPLError(CE_Failure, CPLE_FileIO, "Cannot seek to offset %d", offset);
        return CE_Failure;
    }
    if( VSIFWriteL(pImage, 1, 128 * 128, l_poDS->fdIMG) != 128 * 128 )
    {
        CPLError(CE_Failure, CPLE_FileIO, "Cannot read data at offset %d", offset);
        return CE_Failure;
    }

    return CE_None;
}

static unsigned int WriteSubFieldStr( VSILFILE* fd, const char* pszStr,
                                      unsigned int size )
{
    char* str = (char*)CPLMalloc(size+1);
    memset(str, ' ', size);
    if( strlen(pszStr) > size )
    {
        CPLError(CE_Failure, CPLE_AppDefined, "strlen(pszStr) > size");
        CPLFree(str);
        return size;
    }
    strcpy(str, pszStr);
    str[strlen(pszStr)] = ' ';
    VSIFWriteL(str, 1, size, fd);
    CPLFree(str);
    return size;
}

static unsigned int WriteSubFieldInt(VSILFILE* fd, int val, unsigned int size)
{
    char* str = (char*)CPLMalloc(size+1);
    char formatStr[32];
    snprintf( formatStr, sizeof(formatStr), "%%0%ud", size);
    snprintf( str, size+1, formatStr, val);
    VSIFWriteL(str, 1, size, fd);
    CPLFree(str);
    return size;
}

static unsigned int WriteFieldTerminator(VSILFILE* fd)
{
    char fieldTerminator = 30;
    VSIFWriteL(&fieldTerminator, 1, 1, fd);
    return 1;
}

static unsigned int WriteUnitTerminator(VSILFILE* fd)
{
    char fieldTerminator = 31;
    VSIFWriteL(&fieldTerminator, 1, 1, fd);
    return 1;
}

static unsigned int WriteLongitude(VSILFILE* fd, double val)
{
    char str[11+1];
    const char sign = (val >= 0) ? '+' : '-';
    if( val < 0 ) val = -val;
    const int ddd = (int)val;
    const int mm = (int)((val - ddd) * 60);
    const double ssdotss = ((val - ddd) * 60 - mm) * 60;
    snprintf(str, sizeof(str), "%c%03d%02d%05.2f", sign, ddd, mm, ssdotss);
    CPLAssert((int)strlen(str) == 11);
    VSIFWriteL(str, 1, 11, fd);
    return 11;
}

static unsigned int WriteLatitude(VSILFILE* fd, double val)
{
    char str[10+1];
    const char sign = (val >= 0) ? '+' : '-';
    if( val < 0 ) val = -val;
    const int dd = (int)val;
    const int mm = (int)((val - dd) * 60);
    const double ssdotss = ((val - dd) * 60 - mm) * 60;
    snprintf(str, sizeof(str), "%c%02d%02d%05.2f", sign, dd, mm, ssdotss);
    CPLAssert((int)strlen(str) == 10);
    VSIFWriteL(str, 1, 10, fd);
    return 10;
}

static int BeginLeader(VSILFILE* fd, int sizeFieldLength, int sizeFieldPos, int sizeFieldTag,
                       int nFields)
{
    int pos = (int)VSIFTellL(fd);
    VSIFSeekL(fd, 24 + (sizeFieldLength + sizeFieldPos + sizeFieldTag) * (vsi_l_offset)nFields + 1, SEEK_CUR);
    return pos;
}

static void FinishWriteLeader( VSILFILE* fd, int beginPos, int sizeFieldLength,
                               int sizeFieldPos, int sizeFieldTag,
                               int nFields, int* sizeOfFields,
                               const char** nameOfFields )
{
    const int endPos = (int)VSIFTellL(fd);
    VSIFSeekL(fd, beginPos, SEEK_SET);

    int nLeaderSize = 24;
    char szLeader[24+1];
    memset(szLeader, ' ', nLeaderSize);

    int nDataSize = 0;
    int nFieldOffset = 0;
    for( int i = 0; i < nFields; i++ )
        nDataSize += sizeOfFields[i];
    nFieldOffset =
        (sizeFieldLength + sizeFieldPos + sizeFieldTag) * nFields + 1;
    nDataSize += nFieldOffset;

    snprintf( szLeader+0, sizeof(szLeader)-0,
              "%05d", (int) (nDataSize + nLeaderSize) );
    szLeader[5] = ' ';
    szLeader[6] = 'D';

    snprintf( szLeader+12, sizeof(szLeader)-12, "%05d", (int) (nFieldOffset + nLeaderSize) );
    szLeader[17] = ' ';

    szLeader[20] = (char) ('0' + sizeFieldLength);
    szLeader[21] = (char) ('0' + sizeFieldPos);
    szLeader[22] = '0';
    szLeader[23] = (char) ('0' + sizeFieldTag);

    VSIFWriteL(szLeader, 1, nLeaderSize, fd);

    int acc = 0;
    for(int i=0;i<nFields;i++)
    {
        VSIFWriteL(nameOfFields[i], 1, sizeFieldTag, fd);
        WriteSubFieldInt(fd, sizeOfFields[i], sizeFieldLength);
        WriteSubFieldInt(fd, acc, sizeFieldPos);
        acc += sizeOfFields[i];
    }
    WriteFieldTerminator(fd);

    VSIFSeekL(fd, endPos, SEEK_SET);
}

static int BeginHeader(VSILFILE* fd, int sizeFieldLength, int sizeFieldPos, int sizeFieldTag,
                       int nFields)
{
    int pos = (int)VSIFTellL(fd);
    VSIFSeekL(fd, 24 + (sizeFieldLength + sizeFieldPos + sizeFieldTag) * nFields + 1, SEEK_CUR);
    return pos;
}

static void FinishWriteHeader(VSILFILE* fd, int beginPos, int sizeFieldLength, int sizeFieldPos, int sizeFieldTag,
                             int nFields, int* sizeOfFields, const char** nameOfFields)
{
    int endPos = (int)VSIFTellL(fd);
    VSIFSeekL(fd, beginPos, SEEK_SET);

    int nLeaderSize = 24;
    char szLeader[24+1];
    memset(szLeader, ' ', nLeaderSize);

    int nDataSize = 0;
    int nFieldOffset = 0;
    for(int i=0;i<nFields;i++)
        nDataSize += sizeOfFields[i];
    nFieldOffset = (sizeFieldLength + sizeFieldPos + sizeFieldTag) * nFields + 1;
    nDataSize += nFieldOffset;

    snprintf( szLeader+0, sizeof(szLeader)-0, "%05d", (int) (nDataSize + nLeaderSize) );
    szLeader[5] = '2';
    szLeader[6] = 'L';

    szLeader[10] = '0';
    szLeader[11] = '6';
    snprintf( szLeader+12, sizeof(szLeader)-12, "%05d", (int) (nFieldOffset + nLeaderSize) );
    szLeader[17] = ' ';

    szLeader[20] = (char) ('0' + sizeFieldLength);
    szLeader[21] = (char) ('0' + sizeFieldPos);
    szLeader[22] = '0';
    szLeader[23] = (char) ('0' + sizeFieldTag);

    VSIFWriteL(szLeader, 1, nLeaderSize, fd);

    int acc = 0;
    for(int i=0;i<nFields;i++)
    {
        VSIFWriteL(nameOfFields[i], 1, sizeFieldTag, fd);
        WriteSubFieldInt(fd, sizeOfFields[i], sizeFieldLength);
        WriteSubFieldInt(fd, acc, sizeFieldPos);
        acc += sizeOfFields[i];
    }
    WriteFieldTerminator(fd);

    VSIFSeekL(fd, endPos, SEEK_SET);
}

static int WriteFieldDecl(VSILFILE* fd, char _data_struct_code , char _data_type_code, const char* _fieldName,
                           const char* _arrayDescr, const char* _formatControls)
{
    VSIFWriteL(&_data_struct_code, 1, 1, fd);
    VSIFWriteL(&_data_type_code, 1, 1, fd);
    if( _data_struct_code == ' ' )
    {
        VSIFWriteL("    ", 1 , 4, fd);
    }
    else
    {
        VSIFWriteL("00;&", 1 , 4, fd);
    }
    int len = 6;
    VSIFWriteL(_fieldName, 1, strlen(_fieldName), fd);
    len += static_cast<int>(strlen(_fieldName));
    if( _arrayDescr[0] )
    {
        len += WriteUnitTerminator(fd);
        VSIFWriteL(_arrayDescr, 1, strlen(_arrayDescr), fd);
        len += static_cast<int>(strlen(_arrayDescr));

        len += WriteUnitTerminator(fd);
        VSIFWriteL(_formatControls, 1, strlen(_formatControls), fd);
        len += static_cast<int>(strlen(_formatControls));
    }
    len += WriteFieldTerminator(fd);
    return len;
}

/************************************************************************/
/*                          ADRGDataset()                               */
/************************************************************************/

ADRGDataset::ADRGDataset() :
    fdIMG(nullptr),
    TILEINDEX(nullptr),
    offsetInIMG(0),
    NFC(0),
    NFL(0),
    LSO(0.0),
    PSO(0.0),
    ARV(0),
    BRV(0),
    papszSubDatasets(nullptr),
    poOverviewDS(nullptr),
    bCreation(FALSE),
    fdGEN(nullptr),
    fdTHF(nullptr),
    bGeoTransformValid(0),
    nNextAvailableBlock(0)
{
    memset( adfGeoTransform, 0, sizeof(adfGeoTransform) );
}

/************************************************************************/
/*                          ~ADRGDataset()                              */
/************************************************************************/

ADRGDataset::~ADRGDataset()
{
    if( poOverviewDS )
    {
        delete poOverviewDS;
    }

    CSLDestroy(papszSubDatasets);

    if( bCreation )
    {
        GDALPamDataset::FlushCache();

        /* Write header and padding of image */
        VSIFSeekL(fdIMG, 0, SEEK_SET);
        {
            VSILFILE* fd = fdIMG;
            {
            int nFields = 0;
            int sizeOfFields[] = { 0, 0, 0, 0 };
            const char* nameOfFields[] = { "000", "001", "PAD", "SCN" };
            int pos = BeginHeader(fd, 3, 4, 3, N_ELEMENTS(sizeOfFields));

            sizeOfFields[nFields++] += WriteFieldDecl(fd, ' ', ' ', "GEO_DATA_FILE", "", ""); /* 000 */
            sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '0', "RECORD_ID_FIELD", /* 001 */
                                                    "RTY!RID",
                                                    "(A(3),A(2))");
            sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '0', "PADDING_FIELD", /* PAD */
                                                    "PAD",
                                                    "(A)");
            sizeOfFields[nFields++] += WriteFieldDecl(fd, '2', '0', "PIXEL_FIELD", /* SCN */
                                                    "*PIX",
                                                    "(A(1))");

            FinishWriteHeader(fd, pos, 3, 4, 3, N_ELEMENTS(sizeOfFields), sizeOfFields, nameOfFields);
            }

            /* Write IMAGE_RECORD */
            {
                int nFields = 0;
                int sizeOfFields[] = {0, 0, 0};
                const char* nameOfFields[] = { "001", "PAD", "SCN" };
                int pos = BeginLeader(fd, 9, 9, 3, N_ELEMENTS(sizeOfFields));

                /* Field 001 */
                sizeOfFields[nFields] += WriteSubFieldStr(fd, "IMG", 3); /* RTY */
                sizeOfFields[nFields] += WriteSubFieldStr(fd, "01", 2); /* RID */
                sizeOfFields[nFields] += WriteFieldTerminator(fd);
                nFields++;

                /* Field PAD */
                int endPos = (int)VSIFTellL(fd);
                char* pad = (char*)CPLMalloc(2047 - endPos);
                memset(pad, ' ', 2047 - endPos);
                VSIFWriteL(pad, 1, 2047 - endPos, fd);
                CPLFree(pad);
                WriteFieldTerminator(fd);
                sizeOfFields[nFields] += 2047 - endPos + 1;
                nFields++;

                /* Field SCN */
                sizeOfFields[nFields] = (nNextAvailableBlock - 1) * 128 * 128 * 3;
                nFields++;

                FinishWriteLeader(fd, pos, 9, 9, 3, N_ELEMENTS(sizeOfFields), sizeOfFields, nameOfFields);
            }
        }

        /* Write terminal field terminator */
        int offset = offsetInIMG + (nNextAvailableBlock - 1) * 128 * 128 * 3;
        VSIFSeekL(fdIMG, offset, SEEK_SET);
        WriteFieldTerminator(fdIMG);

        WriteGENFile();
        WriteTHFFile();
    }

    if( fdIMG )
    {
        VSIFCloseL(fdIMG);
    }

    if( fdGEN )
    {
        VSIFCloseL(fdGEN);
    }
    if( fdTHF )
    {
        VSIFCloseL(fdTHF);
    }

    if( TILEINDEX )
    {
        delete [] TILEINDEX;
    }
}

/************************************************************************/
/*                            GetFileList()                             */
/************************************************************************/

char ** ADRGDataset::GetFileList()
{
    char** papszFileList = GDALPamDataset::GetFileList();

    if( !osGENFileName.empty() && !osIMGFileName.empty() )
    {
        CPLString osMainFilename = GetDescription();
        VSIStatBufL sStat;

        const bool bMainFileReal = VSIStatL( osMainFilename, &sStat ) == 0;
        if( bMainFileReal )
        {
            CPLString osShortMainFilename = CPLGetFilename(osMainFilename);
            CPLString osShortGENFileName = CPLGetFilename(osGENFileName);
            if( !EQUAL(osShortMainFilename.c_str(), osShortGENFileName.c_str()) )
                papszFileList = CSLAddString(papszFileList, osGENFileName.c_str());
        }
        else
            papszFileList = CSLAddString(papszFileList, osGENFileName.c_str());

        papszFileList = CSLAddString(papszFileList, osIMGFileName.c_str());
    }

    return papszFileList;
}

/************************************************************************/
/*                           AddSubDataset()                            */
/************************************************************************/

void ADRGDataset::AddSubDataset( const char* pszGENFileName, const char* pszIMGFileName )
{
    char szName[80];
    int nCount = CSLCount(papszSubDatasets ) / 2;

    CPLString osSubDatasetName;
    osSubDatasetName = "ADRG:";
    osSubDatasetName += pszGENFileName;
    osSubDatasetName += ",";
    osSubDatasetName += pszIMGFileName;

    snprintf( szName, sizeof(szName), "SUBDATASET_%d_NAME", nCount+1 );
    papszSubDatasets =
        CSLSetNameValue( papszSubDatasets, szName, osSubDatasetName);

    snprintf( szName, sizeof(szName), "SUBDATASET_%d_DESC", nCount+1 );
    papszSubDatasets =
        CSLSetNameValue( papszSubDatasets, szName, osSubDatasetName);
}

/************************************************************************/
/*                      GetMetadataDomainList()                         */
/************************************************************************/

char **ADRGDataset::GetMetadataDomainList()
{
    return BuildMetadataDomainList(GDALPamDataset::GetMetadataDomainList(),
                                   TRUE,
                                   "SUBDATASETS", NULL);
}

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

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

{
    if( pszDomain != nullptr && EQUAL(pszDomain,"SUBDATASETS") )
        return papszSubDatasets;

    return GDALPamDataset::GetMetadata( pszDomain );
}

/************************************************************************/
/*                        GetProjectionRef()                            */
/************************************************************************/

const char* ADRGDataset::GetProjectionRef()
{
    return osSRS;
}

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

CPLErr ADRGDataset::GetGeoTransform( double * padfGeoTransform)
{
    if( papszSubDatasets != nullptr )
        return CE_Failure;

    memcpy( padfGeoTransform, adfGeoTransform, sizeof(double)*6 );

    return CE_None;
}

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

CPLErr ADRGDataset::SetGeoTransform( double * padfGeoTransform )

{
    memcpy( adfGeoTransform, padfGeoTransform, sizeof(double)*6 );
    bGeoTransformValid = TRUE;
    return CE_None;
}

/************************************************************************/
/*                     GetLongitudeFromString()                         */
/************************************************************************/

double ADRGDataset::GetLongitudeFromString(const char* str)
{
    char ddd[3+1] = { 0 };
    char mm[2+1] = { 0 };
    char ssdotss[5+1] = { 0 };
    int sign = (str[0] == '+') ? 1 : - 1;
    str++;
    strncpy(ddd, str, 3);
    str+=3;
    strncpy(mm, str, 2);
    str+=2;
    strncpy(ssdotss, str, 5);
    return sign * (CPLAtof(ddd) + CPLAtof(mm) / 60 + CPLAtof(ssdotss) / 3600);
}

/************************************************************************/
/*                      GetLatitudeFromString()                         */
/************************************************************************/

double ADRGDataset::GetLatitudeFromString(const char* str)
{
    char ddd[2+1] = { 0 };
    char mm[2+1] = { 0 };
    char ssdotss[5+1] = { 0 };
    int sign = (str[0] == '+') ? 1 : - 1;
    str++;
    strncpy(ddd, str, 2);
    str+=2;
    strncpy(mm, str, 2);
    str+=2;
    strncpy(ssdotss, str, 5);
    return sign * (CPLAtof(ddd) + CPLAtof(mm) / 60 + CPLAtof(ssdotss) / 3600);
}

/************************************************************************/
/*                      FindRecordInGENForIMG()                         */
/************************************************************************/

DDFRecord* ADRGDataset::FindRecordInGENForIMG(DDFModule& module,
                                              const char* pszGENFileName,
                                              const char* pszIMGFileName)
{
    /* Finds the GEN file corresponding to the IMG file */
    if( !module.Open(pszGENFileName, TRUE) )
        return nullptr;

    CPLString osShortIMGFilename = CPLGetFilename(pszIMGFileName);

    /* Now finds the record */
    while (true)
    {
        CPLPushErrorHandler( CPLQuietErrorHandler );
        DDFRecord* record = module.ReadRecord();
        CPLPopErrorHandler();
        CPLErrorReset();
        if( record == nullptr )
          return nullptr;

        if( record->GetFieldCount() >= 5 )
        {
            DDFField *field = record->GetField(0);
            DDFFieldDefn *fieldDefn = field->GetFieldDefn();
            if( !(strcmp(fieldDefn->GetName(), "001") == 0 &&
                fieldDefn->GetSubfieldCount() == 2) )
            {
                continue;
            }

            const char* RTY = record->GetStringSubfield("001", 0, "RTY", 0);
            if( RTY == nullptr )
                continue;
            /* Ignore overviews */
            if( strcmp(RTY, "OVV") == 0 )
                continue;

            if( strcmp(RTY, "GIN") != 0 )
                continue;

            field = record->GetField(3);
            fieldDefn = field->GetFieldDefn();

            if( !(strcmp(fieldDefn->GetName(), "SPR") == 0 &&
                  fieldDefn->GetSubfieldCount() == 15) )
            {
                continue;
            }

            const char* pszBAD = record->GetStringSubfield("SPR", 0, "BAD", 0);
            if( pszBAD == nullptr || strlen(pszBAD) != 12 )
                continue;
            CPLString osBAD = pszBAD;
            {
                char* c = (char*) strchr(osBAD.c_str(), ' ');
                if( c )
                    *c = 0;
            }

            if( EQUAL(osShortIMGFilename.c_str(), osBAD.c_str()) )
            {
                return record;
            }
        }
    }
}

/************************************************************************/
/*                           OpenDataset()                              */
/************************************************************************/

ADRGDataset* ADRGDataset::OpenDataset(
        const char* pszGENFileName, const char* pszIMGFileName, DDFRecord* record)
{
    DDFModule module;

    int SCA = 0;
    int ZNA = 0;
    double PSP;
    int ARV;
    int BRV;
    double LSO;
    double PSO;
    int NFL;
    int NFC;
    CPLString osBAD;
    int TIF;
    int* TILEINDEX = nullptr;

    if( record == nullptr )
    {
        record = FindRecordInGENForIMG(module, pszGENFileName, pszIMGFileName);
        if( record == nullptr )
            return nullptr;
    }

    DDFField* field = record->GetField(1);
    if( field == nullptr )
        return nullptr;
    DDFFieldDefn *fieldDefn = field->GetFieldDefn();

    if( !(strcmp(fieldDefn->GetName(), "DSI") == 0 &&
          fieldDefn->GetSubfieldCount() == 2) )
    {
        return nullptr;
    }

    const char* pszPTR = record->GetStringSubfield("DSI", 0, "PRT", 0);
    if( pszPTR == nullptr || !EQUAL(pszPTR, "ADRG") )
       return nullptr;

    const char* pszNAM = record->GetStringSubfield("DSI", 0, "NAM", 0);
    if( pszNAM == nullptr || strlen(pszNAM) != 8 )
        return nullptr;
    CPLString osNAM = pszNAM;

    field = record->GetField(2);
    if( field == nullptr )
        return nullptr;
    fieldDefn = field->GetFieldDefn();

    // TODO: Support on GIN things.  And what is GIN?
    // GIN might mean general information and might be a typo of GEN.
    // if( isGIN )
    {
        if( !(strcmp(fieldDefn->GetName(), "GEN") == 0 &&
              fieldDefn->GetSubfieldCount() == 21) )
        {
            return nullptr;
        }

        if( record->GetIntSubfield("GEN", 0, "STR", 0) != 3 )
            return nullptr;

        SCA = record->GetIntSubfield("GEN", 0, "SCA", 0);
        CPLDebug("ADRG", "SCA=%d", SCA);

        ZNA = record->GetIntSubfield("GEN", 0, "ZNA", 0);
        CPLDebug("ADRG", "ZNA=%d", ZNA);

        PSP = record->GetFloatSubfield("GEN", 0, "PSP", 0);
        CPLDebug("ADRG", "PSP=%f", PSP);

        ARV = record->GetIntSubfield("GEN", 0, "ARV", 0);
        CPLDebug("ADRG", "ARV=%d", ARV);

        BRV = record->GetIntSubfield("GEN", 0, "BRV", 0);
        CPLDebug("ADRG", "BRV=%d", BRV);
        if( ARV <= 0 || (ZNA != 9 && ZNA != 18 && BRV <= 0) )
            return nullptr;

        const char* pszLSO = record->GetStringSubfield("GEN", 0, "LSO", 0);
        if( pszLSO == nullptr || strlen(pszLSO) != 11 )
            return nullptr;
        LSO = GetLongitudeFromString(pszLSO);
        CPLDebug("ADRG", "LSO=%f", LSO);

        const char* pszPSO = record->GetStringSubfield("GEN", 0, "PSO", 0);
        if( pszPSO == nullptr || strlen(pszPSO) != 10 )
            return nullptr;
        PSO = GetLatitudeFromString(pszPSO);
        CPLDebug("ADRG", "PSO=%f", PSO);
    }
#if 0
    else
    {
        if( !(strcmp(fieldDefn->GetName(), "OVI") == 0 &&
                fieldDefn->GetSubfieldCount() == 5) )
        {
            return NULL;
        }

        if( record->GetIntSubfield("OVI", 0, "STR", 0) != 3 )
            return NULL;

        ARV = record->GetIntSubfield("OVI", 0, "ARV", 0);
        CPLDebug("ADRG", "ARV=%d", ARV);

        BRV = record->GetIntSubfield("OVI", 0, "BRV", 0);
        CPLDebug("ADRG", "BRV=%d", BRV);

        const char* pszLSO = record->GetStringSubfield("OVI", 0, "LSO", 0);
        if( pszLSO == NULL || strlen(pszLSO) != 11 )
            return NULL;
        LSO = GetLongitudeFromString(pszLSO);
        CPLDebug("ADRG", "LSO=%f", LSO);

        const char* pszPSO = record->GetStringSubfield("OVI", 0, "PSO", 0);
        if( pszPSO == NULL || strlen(pszPSO) != 10 )
            return NULL;
        PSO = GetLatitudeFromString(pszPSO);
        CPLDebug("ADRG", "PSO=%f", PSO);
    }
#endif

    field = record->GetField(3);
    if( field == nullptr )
        return nullptr;
    fieldDefn = field->GetFieldDefn();

    if( !(strcmp(fieldDefn->GetName(), "SPR") == 0 &&
          fieldDefn->GetSubfieldCount() == 15))
    {
        return nullptr;
    }

    NFL = record->GetIntSubfield("SPR", 0, "NFL", 0);
    CPLDebug("ADRG", "NFL=%d", NFL);

    NFC = record->GetIntSubfield("SPR", 0, "NFC", 0);
    CPLDebug("ADRG", "NFC=%d", NFC);

    const auto knIntMax = std::numeric_limits<int>::max();
    if( NFL <= 0 || NFC <= 0 ||
        NFL > knIntMax / 128 ||
        NFC > knIntMax / 128 ||
        NFL > (knIntMax - 1) / (NFC * 5) )
    {
        CPLError( CE_Failure, CPLE_AppDefined,"Invalid NFL / NFC values");
        return nullptr;
    }

    int PNC = record->GetIntSubfield("SPR", 0, "PNC", 0);
    CPLDebug("ADRG", "PNC=%d", PNC);
    if( PNC != 128 )
    {
        return nullptr;
    }

    int PNL = record->GetIntSubfield("SPR", 0, "PNL", 0);
    CPLDebug("ADRG", "PNL=%d", PNL);
    if( PNL != 128 )
    {
        return nullptr;
    }

    const char* pszBAD = record->GetStringSubfield("SPR", 0, "BAD", 0);
    if( pszBAD == nullptr || strlen(pszBAD) != 12 )
        return nullptr;
    osBAD = pszBAD;
    {
        char* c = (char*) strchr(osBAD.c_str(), ' ');
        if( c )
            *c = 0;
    }
    CPLDebug("ADRG", "BAD=%s", osBAD.c_str());

    DDFSubfieldDefn* subfieldDefn = fieldDefn->GetSubfield(14);
    if( !(strcmp(subfieldDefn->GetName(), "TIF") == 0 &&
          (subfieldDefn->GetFormat())[0] == 'A') )
    {
        return nullptr;
    }

    const char* pszTIF = record->GetStringSubfield("SPR", 0, "TIF", 0);
    if( pszTIF == nullptr)
        return nullptr;
    TIF = pszTIF[0] == 'Y';
    CPLDebug("ADRG", "TIF=%d", TIF);

    if( TIF )
    {
        if( record->GetFieldCount() != 6 )
        {
            return nullptr;
        }

        field = record->GetField(5);
        if( field == nullptr )
            return nullptr;
        fieldDefn = field->GetFieldDefn();

        if( !(strcmp(fieldDefn->GetName(), "TIM") == 0) )
        {
            return nullptr;
        }

        if( field->GetDataSize() != 5 * NFL * NFC + 1 )
        {
            return nullptr;
        }

        try
        {
            TILEINDEX = new int [NFL * NFC];
        }
        catch( const std::exception& )
        {
            return nullptr;
        }
        const char* ptr = field->GetData();
        char offset[5+1]={0};
        for(int i=0;i<NFL*NFC;i++)
        {
            strncpy(offset, ptr, 5);
            ptr += 5;
            TILEINDEX[i] = atoi(offset);
            //CPLDebug("ADRG", "TSI[%d]=%d", i, TILEINDEX[i]);
        }
    }

    VSILFILE* fdIMG = VSIFOpenL(pszIMGFileName, "rb");
    if( fdIMG == nullptr )
    {
        CPLError(CE_Failure, CPLE_AppDefined, "Cannot open %s\n", pszIMGFileName);
        delete[] TILEINDEX;
        return nullptr;
    }

    /* Skip ISO8211 header of IMG file */
    int offsetInIMG = 0;
    char c;
    char recordName[3];
    if( VSIFReadL(&c, 1, 1, fdIMG) != 1 )
    {
        VSIFCloseL(fdIMG);
        delete[] TILEINDEX;
        return nullptr;
    }
    while (!VSIFEofL(fdIMG))
    {
        if( c == 30 )
        {
            if( VSIFReadL(recordName, 1, 3, fdIMG) != 3 )
            {
                VSIFCloseL(fdIMG);
                delete[] TILEINDEX;
                return nullptr;
            }
            offsetInIMG += 3;
            if( STARTS_WITH(recordName, "IMG") )
            {
                offsetInIMG += 4;
                if( VSIFSeekL(fdIMG,3,SEEK_CUR) != 0 ||
                    VSIFReadL(&c, 1, 1, fdIMG) != 1 )
                {
                    VSIFCloseL(fdIMG);
                    delete[] TILEINDEX;
                    return nullptr;
                }
                while(c ==' ')
                {
                    offsetInIMG ++;
                    if( VSIFReadL(&c, 1, 1, fdIMG) != 1 )
                    {
                        VSIFCloseL(fdIMG);
                        delete[] TILEINDEX;
                        return nullptr;
                    }
                }
                offsetInIMG ++;
                break;
            }
        }

        offsetInIMG++;
        if( VSIFReadL(&c, 1, 1, fdIMG) != 1 )
        {
            VSIFCloseL(fdIMG);
            delete[] TILEINDEX;
            return nullptr;
        }
    }

    if( VSIFEofL(fdIMG) )
    {
        VSIFCloseL(fdIMG);
        delete[] TILEINDEX;
        return nullptr;
    }

    CPLDebug("ADRG", "Img offset data = %d", offsetInIMG);

    ADRGDataset* poDS = new ADRGDataset();

    poDS->osGENFileName = pszGENFileName;
    poDS->osIMGFileName = pszIMGFileName;
    poDS->NFC = NFC;
    poDS->NFL = NFL;
    poDS->nRasterXSize = NFC * 128;
    poDS->nRasterYSize = NFL * 128;
    poDS->LSO = LSO;
    poDS->PSO = PSO;
    poDS->ARV = ARV;
    poDS->BRV = BRV;
    poDS->TILEINDEX = TILEINDEX;
    poDS->fdIMG = fdIMG;
    poDS->offsetInIMG = offsetInIMG;
    poDS->poOverviewDS = nullptr;

    if( ZNA == 9)
    {
        // North Polar Case
        poDS->adfGeoTransform[0] = 111319.4907933 * (90.0 - PSO) * sin(LSO * M_PI / 180.0);
        poDS->adfGeoTransform[1] = 40075016.68558 / ARV;
        poDS->adfGeoTransform[2] = 0.0;
        poDS->adfGeoTransform[3] = -111319.4907933 * (90.0 - PSO) * cos(LSO * M_PI / 180.0);
        poDS->adfGeoTransform[4] = 0.0;
        poDS->adfGeoTransform[5] = -40075016.68558 / ARV;
        poDS->osSRS =
                "PROJCS[\"ARC_System_Zone_09\",GEOGCS[\"GCS_Sphere\","
                "DATUM[\"D_Sphere\",SPHEROID[\"Sphere\",6378137.0,0.0]],"
                "PRIMEM[\"Greenwich\",0],UNIT[\"degree\",0.0174532925199433]],"
                "PROJECTION[\"Azimuthal_Equidistant\"],"
                "PARAMETER[\"latitude_of_center\",90],"
                "PARAMETER[\"longitude_of_center\",0],"
                "PARAMETER[\"false_easting\",0],"
                "PARAMETER[\"false_northing\",0]]";
    }
    else if (ZNA == 18)
    {
        // South Polar Case
        poDS->adfGeoTransform[0] = 111319.4907933 * (90.0 + PSO) * sin(LSO * M_PI / 180.0);
        poDS->adfGeoTransform[1] = 40075016.68558 / ARV;
        poDS->adfGeoTransform[2] = 0.0;
        poDS->adfGeoTransform[3] = 111319.4907933 * (90.0 + PSO) * cos(LSO * M_PI / 180.0);
        poDS->adfGeoTransform[4] = 0.0;
        poDS->adfGeoTransform[5] = -40075016.68558 / ARV;
        poDS->osSRS = "PROJCS[\"ARC_System_Zone_18\",GEOGCS[\"GCS_Sphere\","
                "DATUM[\"D_Sphere\",SPHEROID[\"Sphere\",6378137.0,0.0]],"
                "PRIMEM[\"Greenwich\",0],UNIT[\"degree\",0.0174532925199433]],"
                "PROJECTION[\"Azimuthal_Equidistant\"],"
                "PARAMETER[\"latitude_of_center\",-90],"
                "PARAMETER[\"longitude_of_center\",0],"
                "PARAMETER[\"false_easting\",0],"
                "PARAMETER[\"false_northing\",0]]";
    }
    else
    {
        poDS->adfGeoTransform[0] = LSO;
        poDS->adfGeoTransform[1] = 360. / ARV;
        poDS->adfGeoTransform[2] = 0.0;
        poDS->adfGeoTransform[3] = PSO;
        poDS->adfGeoTransform[4] = 0.0;
        poDS->adfGeoTransform[5] = - 360. / BRV;
        poDS->osSRS = SRS_WKT_WGS84;
    }

    // if( isGIN )
    {
        char szValue[32];
        snprintf( szValue, sizeof(szValue), "%d", SCA);
        poDS->SetMetadataItem( "ADRG_SCA", szValue );
        snprintf( szValue, sizeof(szValue), "%d", ZNA);
        poDS->SetMetadataItem( "ADRG_ZNA", szValue );
     }

    poDS->SetMetadataItem( "ADRG_NAM", osNAM.c_str() );

    poDS->nBands = 3;
    for( int i = 0; i < poDS->nBands; i++ )
        poDS->SetBand( i+1, new ADRGRasterBand( poDS, i+1 ) );

    return poDS;
}

/************************************************************************/
/*                          GetGENListFromTHF()                         */
/************************************************************************/

char** ADRGDataset::GetGENListFromTHF(const char* pszFileName)
{
    DDFModule module;
    DDFRecord *record = nullptr;
    int nFilenames = 0;
    char** papszFileNames = nullptr;

    if( !module.Open(pszFileName, TRUE) )
        return papszFileNames;

    while (true)
    {
        CPLPushErrorHandler( CPLQuietErrorHandler );
        record = module.ReadRecord();
        CPLPopErrorHandler();
        CPLErrorReset();
        if( record == nullptr )
          break;

        if( record->GetFieldCount() >= 2 )
        {
            DDFField *field = record->GetField(0);
            DDFFieldDefn *fieldDefn = field->GetFieldDefn();
            if( !(strcmp(fieldDefn->GetName(), "001") == 0 &&
                fieldDefn->GetSubfieldCount() == 2) )
            {
                continue;
            }

            const char* RTY = record->GetStringSubfield("001", 0, "RTY", 0);
            if( RTY == nullptr || !( strcmp(RTY, "TFN") == 0 ) )
            {
                continue;
            }

            int iVFFFieldInstance = 0;
            for (int i = 1; i < record->GetFieldCount() ; i++)
            {
                field = record->GetField(i);
                fieldDefn = field->GetFieldDefn();

                if( !(strcmp(fieldDefn->GetName(), "VFF") == 0 &&
                      fieldDefn->GetSubfieldCount() == 1) )
                {
                    continue;
                }

                const char* pszVFF = record->GetStringSubfield("VFF", iVFFFieldInstance++, "VFF", 0);
                if( pszVFF == nullptr )
                    continue;
                CPLString osSubFileName(pszVFF);
                char* c = (char*) strchr(osSubFileName.c_str(), ' ');
                if( c )
                    *c = 0;
                if( EQUAL(CPLGetExtension(osSubFileName.c_str()), "GEN") )
                {
                    CPLDebug("ADRG", "Found GEN file in THF : %s", osSubFileName.c_str());
                    CPLString osGENFileName(CPLGetDirname(pszFileName));
                    char** tokens = CSLTokenizeString2( osSubFileName.c_str(), "/\"", 0);
                    char** ptr = tokens;
                    if( ptr == nullptr )
                        continue;
                    while(*ptr)
                    {
                        char** papszDirContent = VSIReadDir(osGENFileName.c_str());
                        char** ptrDir = papszDirContent;
                        if( ptrDir )
                        {
                            while( *ptrDir )
                            {
                                if( EQUAL(*ptrDir, *ptr) )
                                {
                                    osGENFileName = CPLFormFilename(osGENFileName.c_str(), *ptrDir, nullptr);
                                    CPLDebug("ADRG", "Building GEN full file name : %s", osGENFileName.c_str());
                                    break;
                                }
                                ptrDir ++;
                            }
                        }
                        if( ptrDir == nullptr )
                            break;
                        CSLDestroy(papszDirContent);
                        ptr++;
                    }
                    int isNameValid = *ptr == nullptr;
                    CSLDestroy(tokens);
                    if( isNameValid )
                    {
                        papszFileNames = (char**)CPLRealloc(papszFileNames, sizeof(char*) * (nFilenames + 2));
                        papszFileNames[nFilenames] = CPLStrdup(osGENFileName.c_str());
                        papszFileNames[nFilenames + 1] = nullptr;
                        nFilenames ++;
                    }
                }
            }
        }
    }
    return papszFileNames;
}

/************************************************************************/
/*                          GetIMGListFromGEN()                         */
/************************************************************************/

char** ADRGDataset::GetIMGListFromGEN(const char* pszFileName,
                                      int *pnRecordIndex)
{
    DDFRecord *record = nullptr;
    int nFilenames = 0;
    char** papszFileNames = nullptr;
    int nRecordIndex = -1;

    if( pnRecordIndex )
        *pnRecordIndex = -1;

    DDFModule module;
    if( !module.Open(pszFileName, TRUE) )
        return nullptr;

    while (true)
    {
        nRecordIndex ++;

        CPLPushErrorHandler( CPLQuietErrorHandler );
        record = module.ReadRecord();
        CPLPopErrorHandler();
        CPLErrorReset();
        if( record == nullptr )
          break;

        if( record->GetFieldCount() >= 5 )
        {
            DDFField *field = record->GetField(0);
            DDFFieldDefn *fieldDefn = field->GetFieldDefn();
            if( !(strcmp(fieldDefn->GetName(), "001") == 0 &&
                  fieldDefn->GetSubfieldCount() == 2) )
            {
                continue;
            }

            const char* RTY = record->GetStringSubfield("001", 0, "RTY", 0);
            if( RTY == nullptr )
                continue;
            /* Ignore overviews */
            if( strcmp(RTY, "OVV") == 0 )
                continue;

            // TODO: Fix the non-GIN section or remove it.
            if( strcmp(RTY, "GIN") != 0 )
                continue;

            field = record->GetField(3);
            if( field == nullptr )
                continue;
            fieldDefn = field->GetFieldDefn();

            if(!(strcmp(fieldDefn->GetName(), "SPR") == 0 &&
                 fieldDefn->GetSubfieldCount() == 15) )
            {
                continue;
            }

            const char* pszBAD = record->GetStringSubfield("SPR", 0, "BAD", 0);
            if( pszBAD == nullptr || strlen(pszBAD) != 12 )
                continue;
            CPLString osBAD = pszBAD;
            {
                char* c = (char*) strchr(osBAD.c_str(), ' ');
                if( c )
                    *c = 0;
            }
            CPLDebug("ADRG", "BAD=%s", osBAD.c_str());

            /* Build full IMG file name from BAD value */
            CPLString osGENDir(CPLGetDirname(pszFileName));

            CPLString osFileName = CPLFormFilename(osGENDir.c_str(), osBAD.c_str(), nullptr);
            VSIStatBufL sStatBuf;
            if( VSIStatL( osFileName, &sStatBuf ) == 0 )
            {
                osBAD = osFileName;
                CPLDebug("ADRG", "Building IMG full file name : %s", osBAD.c_str());
            }
            else
            {
                char** papszDirContent = nullptr;
                if( strcmp(osGENDir.c_str(), "/vsimem") == 0 )
                {
                    CPLString osTmp = osGENDir + "/";
                    papszDirContent = VSIReadDir(osTmp);
                }
                else
                    papszDirContent = VSIReadDir(osGENDir);
                char** ptrDir = papszDirContent;
                while(ptrDir && *ptrDir)
                {
                    if( EQUAL(*ptrDir, osBAD.c_str()) )
                    {
                        osBAD = CPLFormFilename(osGENDir.c_str(), *ptrDir, nullptr);
                        CPLDebug("ADRG", "Building IMG full file name : %s", osBAD.c_str());
                        break;
                    }
                    ptrDir ++;
                }
                CSLDestroy(papszDirContent);
            }

            if( nFilenames == 0 && pnRecordIndex )
                *pnRecordIndex = nRecordIndex;

            papszFileNames = (char**)CPLRealloc(papszFileNames, sizeof(char*) * (nFilenames + 2));
            papszFileNames[nFilenames] = CPLStrdup(osBAD.c_str());
            papszFileNames[nFilenames + 1] = nullptr;
            nFilenames ++;
        }
    }

    return papszFileNames;
}

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

GDALDataset *ADRGDataset::Open( GDALOpenInfo * poOpenInfo )
{
    int nRecordIndex = -1;
    CPLString osGENFileName;
    CPLString osIMGFileName;
    bool bFromSubdataset = false;

    if( STARTS_WITH_CI(poOpenInfo->pszFilename, "ADRG:") )
    {
        char** papszTokens = CSLTokenizeString2(poOpenInfo->pszFilename + 5, ",", 0);
        if( CSLCount(papszTokens) == 2 )
        {
            osGENFileName = papszTokens[0];
            osIMGFileName = papszTokens[1];
            bFromSubdataset = true;
        }
        CSLDestroy(papszTokens);
    }
    else
    {
        if( poOpenInfo->nHeaderBytes < 500 )
            return nullptr;

        CPLString osFileName(poOpenInfo->pszFilename);
        if( EQUAL(CPLGetExtension(osFileName.c_str()), "THF") )
        {
            char** papszFileNames = GetGENListFromTHF(osFileName.c_str());
            if( papszFileNames == nullptr )
                return nullptr;
            if( papszFileNames[1] == nullptr )
            {
                osFileName = papszFileNames[0];
                CSLDestroy(papszFileNames);
            }
            else
            {
                char** ptr = papszFileNames;
                ADRGDataset* poDS = new ADRGDataset();
                while(*ptr)
                {
                    char** papszIMGFileNames = GetIMGListFromGEN(*ptr);
                    char** papszIMGIter = papszIMGFileNames;
                    while(papszIMGIter && *papszIMGIter)
                    {
                        poDS->AddSubDataset(*ptr, *papszIMGIter);
                        papszIMGIter ++;
                    }
                    CSLDestroy(papszIMGFileNames);

                    ptr ++;
                }
                CSLDestroy(papszFileNames);
                return poDS;
            }
        }

        if( EQUAL(CPLGetExtension(osFileName.c_str()), "GEN") )
        {
            osGENFileName = osFileName;

            char** papszFileNames =
                GetIMGListFromGEN(osFileName.c_str(), &nRecordIndex);
            if( papszFileNames == nullptr )
                return nullptr;
            if( papszFileNames[1] == nullptr )
            {
                osIMGFileName = papszFileNames[0];
                CSLDestroy(papszFileNames);
            }
            else
            {
                char** ptr = papszFileNames;
                ADRGDataset* poDS = new ADRGDataset();
                while( *ptr )
                {
                    poDS->AddSubDataset(osFileName.c_str(), *ptr);
                    ptr ++;
                }
                CSLDestroy(papszFileNames);
                return poDS;
            }
        }
    }

    if( !osGENFileName.empty() &&
        !osIMGFileName.empty() )
    {
        if( poOpenInfo->eAccess == GA_Update )
        {
            CPLError( CE_Failure, CPLE_NotSupported,
                      "The ADRG driver does not support update access to "
                      "existing datasets." );
            return nullptr;
        }

        DDFModule module;
        DDFRecord* record = nullptr;
        if( nRecordIndex >= 0 &&
            module.Open(osGENFileName.c_str(), TRUE) )
        {
            for( int i = 0; i <= nRecordIndex; i++ )
            {
                CPLPushErrorHandler( CPLQuietErrorHandler );
                record = module.ReadRecord();
                CPLPopErrorHandler();
                CPLErrorReset();
                if( record == nullptr )
                  break;
            }
        }

        ADRGDataset* poDS =
            OpenDataset(osGENFileName.c_str(), osIMGFileName.c_str(), record);

        if( poDS )
        {
            /* -------------------------------------------------------------- */
            /*      Initialize any PAM information.                           */
            /* -------------------------------------------------------------- */
            poDS->SetDescription( poOpenInfo->pszFilename );
            poDS->TryLoadXML();

            /* -------------------------------------------------------------- */
            /*      Check for external overviews.                             */
            /* -------------------------------------------------------------- */
            if( bFromSubdataset )
                poDS->oOvManager.Initialize( poDS, osIMGFileName.c_str() );
            else
                poDS->oOvManager.Initialize( poDS, poOpenInfo->pszFilename );

            return poDS;
        }
    }

    return nullptr;
}

/************************************************************************/
/*                               Create()                               */
/************************************************************************/

GDALDataset *ADRGDataset::Create( const char* pszFilename,
                                  int nXSize,
                                  int nYSize,
                                  int nBands,
                                  GDALDataType eType,
                                  CPL_UNUSED char **papszOptions )
{
    if( eType != GDT_Byte)
    {
        CPLError( CE_Failure, CPLE_AppDefined,
              "Attempt to create ADRG dataset with an illegal "
              "data type (%s), only Byte supported by the format.",
              GDALGetDataTypeName(eType) );

        return nullptr;
    }

    if( nBands != 3 )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "ADRG driver doesn't support %d bands. "
                  "Must be 3 (rgb) bands.",
                  nBands );
        return nullptr;
    }

    if(nXSize < 1 || nYSize < 1)
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                "Specified pixel dimensions (% d x %d) are bad.",
                nXSize, nYSize );
    }

    if( !EQUAL(CPLGetExtension(pszFilename), "gen") )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "Invalid filename. Must be ABCDEF01.GEN");
        return nullptr;
    }

    CPLString osBaseFileName(CPLGetBasename(pszFilename));
    if( osBaseFileName.size() != 8 ||
        osBaseFileName[6] != DIGIT_ZERO ||
        osBaseFileName[7] != '1' )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "Invalid filename. "
                  "Must be xxxxxx01.GEN where x is between A and Z" );
        return nullptr;
    }

    for(int i=0;i<6;i++)
    {
        if( !(osBaseFileName[i] >= 'A' && osBaseFileName[i] <= 'Z') )
        {
            CPLError( CE_Failure, CPLE_NotSupported,
                      "Invalid filename. "
                      "Must be xxxxxx01.GEN where x is between A and Z" );
            return nullptr;
        }
    }

    VSILFILE* fdGEN = VSIFOpenL(pszFilename, "wb");
    if( fdGEN == nullptr )
    {
        CPLError( CE_Failure, CPLE_FileIO,
                "Cannot create GEN file : %s.\n", pszFilename);
        return nullptr;
    }

    CPLString osDirname(CPLGetDirname(pszFilename));
    CPLString osTransh01THF(
        CPLFormFilename(osDirname.c_str(), "TRANSH01.THF", nullptr));
    VSILFILE* fdTHF = VSIFOpenL(osTransh01THF.c_str(), "wb");
    if( fdTHF == nullptr )
    {
        VSIFCloseL(fdGEN);
        CPLError( CE_Failure, CPLE_FileIO,
                "Cannot create THF file : %s.\n", osTransh01THF.c_str());
        return nullptr;
    }

    CPLString osImgFilename = CPLResetExtension(pszFilename, "IMG");
    VSILFILE* fdIMG = VSIFOpenL(osImgFilename.c_str(), "w+b");
    if( fdIMG == nullptr )
    {
        VSIFCloseL(fdGEN);
        VSIFCloseL(fdTHF);
        CPLError( CE_Failure, CPLE_FileIO,
                "Cannot create image file : %s.\n", osImgFilename.c_str());
        return nullptr;
    }

    ADRGDataset* poDS = new ADRGDataset();

    poDS->eAccess = GA_Update;

    poDS->fdGEN = fdGEN;
    poDS->fdIMG = fdIMG;
    poDS->fdTHF = fdTHF;

    poDS->osBaseFileName = osBaseFileName;
    poDS->bCreation = TRUE;
    poDS->nNextAvailableBlock = 1;
    poDS->NFC = (nXSize + 127) / 128;
    poDS->NFL = (nYSize + 127) / 128;
    poDS->nRasterXSize = nXSize;
    poDS->nRasterYSize = nYSize;
    poDS->bGeoTransformValid = FALSE;
    poDS->TILEINDEX = new int [poDS->NFC*poDS->NFL];
    memset(poDS->TILEINDEX, 0, sizeof(int)*poDS->NFC*poDS->NFL);
    poDS->offsetInIMG = 2048;
    poDS->poOverviewDS = nullptr;

    poDS->nBands = 3;
    for( int i = 0; i < poDS->nBands; i++ )
        poDS->SetBand( i+1, new ADRGRasterBand( poDS, i+1 ) );

    return poDS;
}

/************************************************************************/
/*                  WriteGENFile_Header()                               */
/************************************************************************/

static void WriteGENFile_Header( VSILFILE* fd )
{
    int nFields = 0;
    int sizeOfFields[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, };
    const char* nameOfFields[] = { "000", "001", "DRF", "DSI", "OVI", "GEN", "SPR", "BDF", "TIM" };
    const int pos = BeginHeader(fd, 3, 4, 3, N_ELEMENTS(sizeOfFields));

    sizeOfFields[nFields++] += WriteFieldDecl(fd, ' ', ' ', "GENERAL_INFORMATION_FILE", "", ""); /* 000 */
    sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '0', "RECORD_ID_FIELD", /* 001 */
                                                "RTY!RID",
                                                "(A(3),A(2))");
    sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '1', "DATA_SET_DESCRIPTION_FIELD", /* DRF */
                                                "NSH!NSV!NOZ!NOS",
                                                "(4I(2))");
    sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '0', "DATA_SET-ID_FIELD", /* DSI */
                                                "PRT!NAM",
                                                "(A(4),A(8))");
    sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '6', "OVERVIEW_INFORMATION_FIELD", /* OVI */
                                                "STR!ARV!BRV!LSO!PSO",
                                                "(I(1),I(8),I(8),A(11),A(10))");
    sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '6', "GENERAL_INFORMATION_FIELD", /* GEN */
                                                "STR!LOD!LAD!UNIloa!SWO!SWA!NWO!NWA!NEO!NEA!SEO!SEA!SCA!ZNA!PSP!IMR!ARV!BRV!LSO!PSO!TXT",
                                                "(I(1),2R(6),I(3),A(11),A(10),A(11),A(10),A(11),A(10),A(11),A(10),I(9),I(2),R(5),A(1),2I(8),A(11),A(10),A(64))");
    sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '6', "DATA_SET_PARAMETERS_FIELD", /* SPR */
                                                "NUL!NUS!NLL!NLS!NFL!NFC!PNC!PNL!COD!ROD!POR!PCB!PVB!BAD!TIF",
                                                "(4I(6),2I(3),2I(6),5I(1),A(12),A(1))");
    sizeOfFields[nFields++] += WriteFieldDecl(fd, '2', '6', "BAND_ID_FIELD", /* BDF */
                                                "*BID!WS1!WS2",
                                                "(A(5),I(5),I(5))");
    sizeOfFields[nFields++] += WriteFieldDecl(fd, '2', '1', "TILE_INDEX_MAP_FIELD", /* TIM */
                                                "*TSI",
                                                "(I(5))");

    FinishWriteHeader(fd, pos, 3, 4, 3, N_ELEMENTS(sizeOfFields),
                      sizeOfFields, nameOfFields);
}

/************************************************************************/
/*            WriteGENFile_DataSetDescriptionRecord()                   */
/************************************************************************/

/* Write DATA_SET_DESCRIPTION_RECORD */
static void WriteGENFile_DataSetDescriptionRecord(VSILFILE* fd)
{
    int nFields = 0;
    int sizeOfFields[] = {0, 0};
    const char* nameOfFields[] = { "001", "DRF" };
    const int pos = BeginLeader(fd, 3, 4, 3, N_ELEMENTS(sizeOfFields));

    /* Field 001 */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "DSS", 3); /* RTY */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "01", 2); /* RID */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field DRF */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 2); /* NSH */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 2); /* NSV */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 2); /* NOZ */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 2); /* NOS */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    /* nFields++; */

    FinishWriteLeader(fd, pos, 3, 4, 3, N_ELEMENTS(sizeOfFields),
                      sizeOfFields, nameOfFields);
}

/************************************************************************/
/*                    WriteGENFile_OverviewRecord()                     */
/************************************************************************/

/* Write OVERVIEW_RECORD */
static void WriteGENFile_OverviewRecord(
    VSILFILE* fd, CPLString& osBaseFileName,
    int ARV, int BRV, double LSO, double PSO,
    int nOvSizeX, int nOvSizeY, int NFL, int NFC, int* TILEINDEX )
{
    int nFields = 0;
    int sizeOfFields[] = {0, 0, 0, 0, 0, 0};
    const char* nameOfFields[] = { "001", "DSI", "OVI", "SPR", "BDF", "TIM" };
    const int pos = BeginLeader(fd, 9, 9, 3, N_ELEMENTS(sizeOfFields));

    /* Field 001 */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "OVV", 3); /* RTY */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "01", 2); /* RID */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field DSI */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "ADRG", 4); /* PRT */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, osBaseFileName, 8); /* NAM */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field OVI */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 3, 1); /* STR */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, ARV, 8);  // ARV - FIXME
    sizeOfFields[nFields] += WriteSubFieldInt(fd, BRV, 8);  // BRV - FIXME
    sizeOfFields[nFields] += WriteLongitude(fd, LSO); /* LSO */   /* FIXME */
    sizeOfFields[nFields] += WriteLatitude(fd, PSO); /* PSO */    /* FIXME */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field SPR */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 6); /* NUL */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, nOvSizeX-1, 6); /* NUS */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, nOvSizeY-1, 6); /* NLL */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 6); /* NLS */
    sizeOfFields[nFields] +=
        WriteSubFieldInt(fd, (nOvSizeY + 127) / 128, 3); /* NFL */
    sizeOfFields[nFields] +=
        WriteSubFieldInt(fd, (nOvSizeX + 127) / 128, 3); /* NFC */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 128, 6); /* PNC */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 128, 6); /* PNL */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 1); /* COD */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 1); /* ROD */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 1); /* POR */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 1); /* PCB */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 8, 1); /* PVB */
    char tmp[12+1];
    snprintf(tmp, sizeof(tmp), "%s.IMG", osBaseFileName.c_str()); /* FIXME */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, tmp, 12); /* BAD */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "Y", 1); /* TIF */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field BDF */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "Red", 5); /* BID */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS1 */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS2 */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "Green", 5); /* BID */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS1 */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS2 */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "Blue", 5); /* BID */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS1 */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS2 */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field TIM */
    for( int i = 0; i < NFL * NFC; i++ )
    {
        sizeOfFields[nFields] += WriteSubFieldInt(fd, TILEINDEX[i], 5);  // TSI
    }
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    /* nFields++; */

    FinishWriteLeader(fd, pos, 9, 9, 3, N_ELEMENTS(sizeOfFields),
                      sizeOfFields, nameOfFields);
}

/************************************************************************/
/*              WriteGENFile_GeneralInformationRecord()                 */
/************************************************************************/

/* Write GENERAL_INFORMATION_RECORD */
static void WriteGENFile_GeneralInformationRecord(
    VSILFILE* fd, CPLString& osNAM, CPLString& osBAD,
    int ARV, int BRV, double LSO, double PSO,
    double* adfGeoTransform, int SCA,
    int nRasterXSize, int nRasterYSize,
    int NFL, int NFC, int* TILEINDEX )

{
    int nFields = 0;
    int sizeOfFields[] = {0, 0, 0, 0, 0, 0};
    const char* nameOfFields[] = { "001", "DSI", "GEN", "SPR", "BDF", "TIM" };
    int pos = BeginLeader(fd, 9, 9, 3, N_ELEMENTS(sizeOfFields));

    /* Field 001 */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "GIN", 3); /* RTY */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "01", 2); /* RID */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field DSI */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "ADRG", 4); /* PRT */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, osNAM.c_str(), 8); /* NAM */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field `GEN */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 3, 1); /* STR */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "0099.9", 6);  // LOD - FIXME
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "0099.9", 6);  // LAD - FIXME
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 16, 3);  // UNIloa - FIXME
    sizeOfFields[nFields] += WriteLongitude(fd, LSO); /* SWO */
    sizeOfFields[nFields] +=
        WriteLatitude(fd, PSO + nRasterYSize * adfGeoTransform[5]); /* SWA */
    sizeOfFields[nFields] += WriteLongitude(fd, LSO); /* NWO */
    sizeOfFields[nFields] += WriteLatitude(fd, PSO); /* NWA */
    sizeOfFields[nFields] +=
        WriteLongitude(fd, LSO + nRasterXSize * adfGeoTransform[1]); /* NEO */
    sizeOfFields[nFields] += WriteLatitude(fd, PSO); /* NEA */
    sizeOfFields[nFields] +=
        WriteLongitude(fd, LSO + nRasterXSize * adfGeoTransform[1]); /* SEO */
    sizeOfFields[nFields] +=
        WriteLatitude(fd, PSO + nRasterYSize * adfGeoTransform[5]); /* SEA */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, SCA, 9); /* SCA */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 2); /* ZNA */  /* FIXME */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "100.0", 5); /* PSP */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "N", 1); /* IMR */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, ARV, 8); /* ARV */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, BRV, 8); /* BRV */
    sizeOfFields[nFields] += WriteLongitude(fd, LSO); /* LSO */
    sizeOfFields[nFields] += WriteLatitude(fd, PSO); /* PSO */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "", 64); /* TXT */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field SPR */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 6); /* NUL */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, nRasterXSize-1, 6); /* NUS */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, nRasterYSize-1, 6); /* NLL */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 6); /* NLS */
    sizeOfFields[nFields] +=
        WriteSubFieldInt(fd, (nRasterYSize + 127) / 128, 3); /* NFL */
    sizeOfFields[nFields] +=
        WriteSubFieldInt(fd, (nRasterXSize + 127) / 128, 3); /* NFC */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 128, 6); /* PNC */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 128, 6); /* PNL */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 1); /* COD */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 1); /* ROD */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 1); /* POR */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 1); /* PCB */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 8, 1); /* PVB */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, osBAD.c_str(), 12); /* BAD */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "Y", 1); /* TIF */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field BDF */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "Red", 5); /* BID */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS1 */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS2 */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "Green", 5); /* BID */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS1 */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS2 */
    sizeOfFields[nFields] += WriteSubFieldStr(fd, "Blue", 5); /* BID */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS1 */
    sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS2 */
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    nFields++;

    /* Field TIM */
    for( int i = 0; i < NFL*NFC; i++ )
    {
        sizeOfFields[nFields] += WriteSubFieldInt(fd, TILEINDEX[i], 5);  // TSI
    }
    sizeOfFields[nFields] += WriteFieldTerminator(fd);
    /* nFields++; */

    FinishWriteLeader(fd, pos, 9, 9, 3, N_ELEMENTS(sizeOfFields),
                      sizeOfFields, nameOfFields);
}

/************************************************************************/
/*                        WriteGENFile()                                */
/************************************************************************/

void ADRGDataset::WriteGENFile()
{
    if( !bGeoTransformValid )
    {
        CPLError(CE_Failure, CPLE_AppDefined, "No geo transform available !");
        adfGeoTransform[0] = 0;
        adfGeoTransform[3] = 0;
        adfGeoTransform[1] = 1;
        adfGeoTransform[5] = 1;
    }

    LSO = adfGeoTransform[0];
    PSO = adfGeoTransform[3];
    ARV = (int)floor(360. / adfGeoTransform[1] + .5);
    BRV = (int)floor(-360. / adfGeoTransform[5] + .5);

    /*ARV = ((ARV + 255) / 512) * 512;
    BRV = ((BRV + 255) / 512) * 512;*/

    const int SCA = (int)floor(1000000. * 400384 / BRV + 0.5);

    const int nOvSizeX = nRasterXSize; // FIXME
    const int nOvSizeY = nRasterYSize; // FIXME

    /* Write header */
    WriteGENFile_Header(fdGEN);

    /* Write DATA_SET_DESCRIPTION_RECORD */
    WriteGENFile_DataSetDescriptionRecord(fdGEN);

    /* Write OVERVIEW_RECORD */
    WriteGENFile_OverviewRecord(fdGEN, osBaseFileName, ARV, BRV, LSO, PSO,
                                nOvSizeX, nOvSizeY, NFL, NFC, TILEINDEX);

    /* Write GENERAL_INFORMATION_RECORD */
    CPLString osNAM = osBaseFileName;
    char tmp[12+1] = {};
    snprintf(tmp, sizeof(tmp), "%s.IMG", osNAM.c_str());
    CPLString osBAD = tmp;
    WriteGENFile_GeneralInformationRecord(
        fdGEN, osNAM, osBAD, ARV, BRV, LSO, PSO,
        adfGeoTransform, SCA, nRasterXSize, nRasterYSize, NFL, NFC, TILEINDEX);

    if( CPLTestBool(CPLGetConfigOption("ADRG_SIMULATE_MULTI_IMG", "OFF")) )
    {
        strncpy(tmp, osBaseFileName.c_str(), 6);
        tmp[6] = '\0';
        strcat(tmp, "02");
        osNAM = tmp;
        snprintf(tmp, sizeof(tmp), "%s.IMG", osNAM.c_str());
        osBAD = tmp;
        WriteGENFile_GeneralInformationRecord(
            fdGEN, osNAM, osBAD, ARV, BRV, LSO, PSO,
            adfGeoTransform, SCA, nRasterXSize, nRasterYSize,
            NFL, NFC, TILEINDEX);
    }
}

/************************************************************************/
/*                        WriteTHFFile()                                */
/************************************************************************/

void ADRGDataset::WriteTHFFile()
{
    VSILFILE* fd = fdTHF;

    /* Write header */
    {
        int nFields = 0;
        int sizeOfFields[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        const char* nameOfFields[] = { "000", "001", "VDR", "FDR", "QSR", "QUV", "CPS", "CPT", "SPR", "BDF", "VFF"};
        const int pos = BeginHeader(fd, 3, 4, 3, N_ELEMENTS(sizeOfFields));

        sizeOfFields[nFields++] += WriteFieldDecl(fd, ' ', ' ', "TRANSMITTAL_HEADER_FILE", "", ""); /* 000 */
        sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '0', "RECORD_ID_FIELD", /* 001 */
                                                  "RTY!RID",
                                                  "(A(3),A(2))");
        sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '6', "TRANSMITTAL_HEADER_FIELD", /* VDR */
                                                  "MSD!VOO!ADR!NOV!SQN!NOF!URF!EDN!DAT",
                                                  "(A(1),A(200),A(1),I(1),I(1),I(3),A(16),I(3),A(12))");
        sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '6', "DATA_SET_DESCRIPTION_FIELD", /* FDR */
                                                  "NAM!STR!PRT!SWO!SWA!NEO!NEA",
                                                  "(A(8),I(1),A(4),A(11),A(10),A(11),A(10))");
        sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '0', "SECURITY_AND_RELEASE_FIELD", /* QSR */
                                                  "QSS!QOD!DAT!QLE",
                                                  "(A(1),A(1),A(12),A(200))");
        sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '0', "VOLUME_UP_TO_DATENESS_FIELD", /* QUV */
                                                  "SRC!DAT!SPA",
                                                  "(A(100),A(12),A(20))");
        sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '6', "TEST_PATCH_IDENTIFIER_FIELD", /* CPS */
                                                  "PNM!DWV!REF!PUR!PIR!PIG!PIB",
                                                  "(A(7),I(6),R(5),R(5),I(3),I(3),I(3))");
        sizeOfFields[nFields++] += WriteFieldDecl(fd, '1', '6', "TEST_PATCH_INFORMATION_FIELD", /* CPT */
                                                  "STR!SCR",
                                                  "(I(1),A(100))");
        sizeOfFields[nFields++] +=
            WriteFieldDecl(
                fd, '1', '6', "DATA_SET_PARAMETERS_FIELD", /* SPR */
                "NUL!NUS!NLL!NLS!NFL!NFC!PNC!PNL!COD!ROD!POR!PCB!PVB!BAD!TIF",
                "(I(6),I(6),I(6),I(6),I(3),I(3),I(6),I(6),I(1),I(1),I(1),I(1),"
                "I(1),A(12),A(1))");
        sizeOfFields[nFields++] +=
            WriteFieldDecl(fd, '2', '6', "BAND_ID_FIELD", /* BDF */
                           "*BID!WS1!WS2",
                           "(A(5),I(5),I(5))");
        sizeOfFields[nFields++] +=
            WriteFieldDecl(fd, '1', '0', "TRANSMITTAL_FILENAMES_FIELD",
                           "VFF", "(A(51))");

        FinishWriteHeader(fd, pos, 3, 4, 3, N_ELEMENTS(sizeOfFields),
                          sizeOfFields, nameOfFields);
    }

    /* Write TRANSMITTAL_DESCRIPTION_RECORD */
    {
        int nFields = 0;
        int sizeOfFields[] = {0, 0, 0};
        const char* nameOfFields[] = { "001", "VDR", "FDR" };
        int pos = BeginLeader(fd, 3, 4, 3, N_ELEMENTS(sizeOfFields));

        /* Field 001 */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "VTH", 3); /* RTY */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "01", 2); /* RID */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field VDR */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, " ", 1); /* MSD */
        // VOO - Title and address of originator
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "", 200);
        sizeOfFields[nFields] += WriteSubFieldStr(fd, " ", 1); /* ADR */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 1); /* NOV */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 1); /* SQN */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 3); /* NOF */
        // URF - DMA stock number for this CDROM
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "", 16);
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 3); /* EDN */
        sizeOfFields[nFields] +=
            WriteSubFieldStr(fd, "017,19940101", 12); // DAT - Publication date
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field FDR */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, osBaseFileName, 8); // NAM
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 3, 1); /* STR */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "ADRG", 4); /* PRT */
        sizeOfFields[nFields] += WriteLongitude(fd, LSO); /* SWO */
        sizeOfFields[nFields] +=
            WriteLatitude(fd, PSO + nRasterYSize * adfGeoTransform[5]);  // SWA
        sizeOfFields[nFields] +=
            WriteLongitude(fd, LSO + nRasterXSize * adfGeoTransform[1]);  // NEO
        sizeOfFields[nFields] += WriteLatitude(fd, PSO); /* NEA */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        /* nFields++; */

        FinishWriteLeader(fd, pos, 3, 4, 3, N_ELEMENTS(sizeOfFields),
                          sizeOfFields, nameOfFields);
    }

    /* Write SECURITY_AND_UPDATE_RECORD */
    {
        int nFields = 0;
        int sizeOfFields[] = {0, 0, 0};
        const char* nameOfFields[] = { "001", "QSR", "QUV" };
        int pos = BeginLeader(fd, 3, 4, 3, N_ELEMENTS(sizeOfFields));

        /* Field 001 */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "LCF", 3); /* RTY */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "01", 2); /* RID */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field VDR */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "U", 1); /* QSS */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "N", 1); /* QOD */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "", 12); /* DAT */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "", 200); /* QLE */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field FDR */
        sizeOfFields[nFields] +=
            WriteSubFieldStr(
                fd,
                "MILITARY SPECIFICATION ARC DIGITIZED RASTER GRAPHICS (ADRG)",
                100); /* SRC */
        sizeOfFields[nFields] +=
            WriteSubFieldStr(fd, "022,19900222", 12); /* DAT */
        sizeOfFields[nFields] +=
            WriteSubFieldStr(fd, "MIL-A-89007", 20); /* SPA */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        /* nFields++; */

        FinishWriteLeader(fd, pos, 3, 4, 3, N_ELEMENTS(sizeOfFields),
                          sizeOfFields, nameOfFields);
    }

    /* Write TEST_PATCH_DATA_RECORD */
    {
        int nFields = 0;
        int sizeOfFields[] = {0, 0, 0, 0, 0};
        const char* nameOfFields[] = { "001", "CPS", "CPT", "SPR", "BDF" };
        const int pos = BeginLeader(fd, 3, 4, 3, N_ELEMENTS(sizeOfFields));

        /* Field 001 */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "TPA", 3); /* RTY */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "01", 2); /* RID */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field CPS */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "Black", 7); /* PNM */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "", 6); /* DMV */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "", 5); /* REF */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "", 5); /* PUR */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 3); /* PIR */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 3); /* PIG */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 3); /* PIB */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field CPT */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 3, 1); /* STR */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "", 100); /* SCR */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        const int nPatchXSize = 512;
        const int nPatchYSize = 512;

        /* Field SPR */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 6); /* NUL */
        sizeOfFields[nFields] +=
            WriteSubFieldInt(fd, nPatchXSize-1, 6); /* NUS */
        sizeOfFields[nFields] +=
            WriteSubFieldInt(fd, nPatchYSize-1, 6); /* NLL */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 6); /* NLS */
        sizeOfFields[nFields] +=
            WriteSubFieldInt(fd, (nPatchYSize + 127) / 128, 3); /* NFL */
        sizeOfFields[nFields] +=
            WriteSubFieldInt(fd, (nPatchXSize + 127) / 128, 3); /* NFC */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 128, 6); /* PNC */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 128, 6); /* PNL */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 1); /* COD */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 1, 1); /* ROD */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 1); /* POR */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 1); /* PCB */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 8, 1); /* PVB */
        // BAD
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "TESTPA01.CPH", 12);
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "N", 1); /* TIF */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field BDF */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "Red", 5); /* BID */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS1 */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS2 */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "Green", 5); /* BID */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS1 */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS2 */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "Blue", 5); /* BID */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS1 */
        sizeOfFields[nFields] += WriteSubFieldInt(fd, 0, 5); /* WS2 */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        /* nFields++; */

        FinishWriteLeader(fd, pos, 3, 4, 3, N_ELEMENTS(sizeOfFields),
                          sizeOfFields, nameOfFields);
    }

    /* Write TRANSMITTAL_FILENAMES_RECORD */
    {
        int nFields = 0;
        int sizeOfFields[] = {0, 0, 0, 0, 0, 0, 0};

        /* Debug option to simulate ADRG datasets made of several images */
        int nTotalFields =
            CPLTestBool(CPLGetConfigOption("ADRG_SIMULATE_MULTI_IMG", "OFF"))
            ? 6 : 5;

        const char* nameOfFields[] = {
            "001", "VFF", "VFF", "VFF", "VFF", "VFF", "VFF" };
        const int pos = BeginLeader(fd, 9, 9, 3, nTotalFields);

        /* Field 001 */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "TFN", 3); /* RTY */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "01", 2); /* RID */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field VFF */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "TRANSH01.THF", 51);
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field VFF */
        sizeOfFields[nFields] += WriteSubFieldStr(fd, "TESTPA01.CPH", 51);
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field VFF */
        char tmp[12+1] = {};
        snprintf(tmp, sizeof(tmp), "%s.GEN", osBaseFileName.c_str());
        sizeOfFields[nFields] += WriteSubFieldStr(fd, tmp, 51); /* VFF */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        /* Field VFF */
        snprintf(tmp, sizeof(tmp), "%s.IMG", osBaseFileName.c_str());
        sizeOfFields[nFields] += WriteSubFieldStr(fd, tmp, 51); /* VFF */
        sizeOfFields[nFields] += WriteFieldTerminator(fd);
        nFields++;

        if( nTotalFields == 6 )
        {
            /* Field VFF */
            strncpy(tmp, osBaseFileName.c_str(), 6);
            tmp[6] = '\0';
            strcat(tmp, "02.IMG");
            sizeOfFields[nFields] += WriteSubFieldStr(fd, tmp, 51); /* VFF */
            sizeOfFields[nFields] += WriteFieldTerminator(fd);
            /* nFields++; */
        }

        FinishWriteLeader(fd, pos, 9, 9, 3, nTotalFields,
                          sizeOfFields, nameOfFields);
    }
}

/************************************************************************/
/*                         GDALRegister_ADRG()                          */
/************************************************************************/

void GDALRegister_ADRG()

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

    GDALDriver *poDriver = new GDALDriver();

    poDriver->SetDescription( "ADRG" );
    poDriver->SetMetadataItem( GDAL_DCAP_RASTER, "YES" );
    poDriver->SetMetadataItem( GDAL_DMD_LONGNAME,
                               "ARC Digitized Raster Graphics" );
    poDriver->SetMetadataItem( GDAL_DMD_HELPTOPIC,
                               "frmt_various.html#ADRG" );
    poDriver->SetMetadataItem( GDAL_DMD_EXTENSION, "gen" );
    poDriver->SetMetadataItem( GDAL_DMD_CREATIONDATATYPES,
                               "Byte" );
    poDriver->SetMetadataItem( GDAL_DMD_SUBDATASETS, "YES" );
    poDriver->SetMetadataItem( GDAL_DCAP_VIRTUALIO, "YES" );

    poDriver->pfnOpen = ADRGDataset::Open;
    poDriver->pfnCreate = ADRGDataset::Create;

    GetGDALDriverManager()->RegisterDriver( poDriver );
}