GDALDataset *JDEMDataset::Open( GDALOpenInfo *poOpenInfo )
{
// Confirm that the header is compatible with a JDEM dataset.
if (!Identify(poOpenInfo))
return nullptr;
// Confirm the requested access is supported.
if( poOpenInfo->eAccess == GA_Update )
{
CPLError(CE_Failure, CPLE_NotSupported,
"The JDEM driver does not support update access to existing "
"datasets.");
return nullptr;
}
// Check that the file pointer from GDALOpenInfo* is available.
if( poOpenInfo->fpL == nullptr )
{
return nullptr;
}
// Create a corresponding GDALDataset.
JDEMDataset *poDS = new JDEMDataset();
// Borrow the file pointer from GDALOpenInfo*.
poDS->fp = poOpenInfo->fpL;
poOpenInfo->fpL = nullptr;
// Read the header.
CPL_IGNORE_RET_VAL(VSIFReadL(poDS->abyHeader, 1, 1012, poDS->fp));
const char *psHeader = reinterpret_cast<char *>(poDS->abyHeader);
poDS->nRasterXSize = JDEMGetField(psHeader + 23, 3);
poDS->nRasterYSize = JDEMGetField(psHeader + 26, 3);
if( poDS->nRasterXSize <= 0 || poDS->nRasterYSize <= 0 )
{
CPLError(CE_Failure, CPLE_AppDefined,
"Invalid dimensions : %d x %d",
poDS->nRasterXSize, poDS->nRasterYSize);
delete poDS;
return nullptr;
}
// Create band information objects.
poDS->SetBand(1, new JDEMRasterBand(poDS, 1));
// Initialize any PAM information.
poDS->SetDescription(poOpenInfo->pszFilename);
poDS->TryLoadXML();
// Check for overviews.
poDS->oOvManager.Initialize(poDS, poOpenInfo->pszFilename);
return poDS;
}
CPLErr JDEMRasterBand::IReadBlock( CPL_UNUSED int nBlockXOff,
int nBlockYOff,
void * pImage )
{
JDEMDataset *poGDS = (JDEMDataset *) poDS;
int i;
if (pszRecord == NULL)
{
if (bBufferAllocFailed)
return CE_Failure;
pszRecord = (char *) VSIMalloc(nRecordSize);
if (pszRecord == NULL)
{
CPLError(CE_Failure, CPLE_OutOfMemory,
"Cannot allocate scanline buffer");
bBufferAllocFailed = TRUE;
return CE_Failure;
}
}
VSIFSeekL( poGDS->fp, 1011 + nRecordSize*nBlockYOff, SEEK_SET );
VSIFReadL( pszRecord, 1, nRecordSize, poGDS->fp );
if( !EQUALN((char *) poGDS->abyHeader,pszRecord,6) )
{
CPLError( CE_Failure, CPLE_AppDefined,
"JDEM Scanline corrupt. Perhaps file was not transferred\n"
"in binary mode?" );
return CE_Failure;
}
if( JDEMGetField( pszRecord + 6, 3 ) != nBlockYOff + 1 )
{
CPLError( CE_Failure, CPLE_AppDefined,
"JDEM scanline out of order, JDEM driver does not\n"
"currently support partial datasets." );
return CE_Failure;
}
for( i = 0; i < nBlockXSize; i++ )
((float *) pImage)[i] = (float)
(JDEMGetField( pszRecord + 9 + 5 * i, 5) * 0.1);
return CE_None;
}
CPLErr JDEMRasterBand::IReadBlock( CPL_UNUSED int nBlockXOff,
int nBlockYOff,
void * pImage )
{
JDEMDataset *poGDS = static_cast<JDEMDataset *>(poDS);
if (pszRecord == nullptr)
{
if (bBufferAllocFailed)
return CE_Failure;
pszRecord = static_cast<char *>(VSI_MALLOC_VERBOSE(nRecordSize));
if (pszRecord == nullptr)
{
bBufferAllocFailed = true;
return CE_Failure;
}
}
CPL_IGNORE_RET_VAL(
VSIFSeekL(poGDS->fp, 1011 + nRecordSize * nBlockYOff, SEEK_SET));
CPL_IGNORE_RET_VAL(VSIFReadL(pszRecord, 1, nRecordSize, poGDS->fp));
if( !EQUALN(reinterpret_cast<char *>(poGDS->abyHeader), pszRecord, 6) )
{
CPLError(CE_Failure, CPLE_AppDefined,
"JDEM Scanline corrupt. Perhaps file was not transferred "
"in binary mode?");
return CE_Failure;
}
if( JDEMGetField(pszRecord + 6, 3) != nBlockYOff + 1 )
{
CPLError(CE_Failure, CPLE_AppDefined,
"JDEM scanline out of order, JDEM driver does not "
"currently support partial datasets.");
return CE_Failure;
}
for( int i = 0; i < nBlockXSize; i++ )
static_cast<float *>(pImage)[i] =
JDEMGetField(pszRecord + 9 + 5 * i, 5) * 0.1f;
return CE_None;
}
static double JDEMGetAngle( char *pszField )
{
int nAngle = JDEMGetField( pszField, 7 );
// Note, this isn't very general purpose, but it would appear
// from the field widths that angles are never negative. Nice
// to be a country in the "first quadrant".
const int nDegree = nAngle / 10000;
const int nMin = (nAngle / 100) % 100;
const int nSec = nAngle % 100;
return nDegree + nMin / 60.0 + nSec / 3600.0;
}
GDALDataset *JDEMDataset::Open( GDALOpenInfo * poOpenInfo )
{
/* -------------------------------------------------------------------- */
/* Confirm that the header is compatible with a JDEM dataset. */
/* -------------------------------------------------------------------- */
if (!Identify(poOpenInfo))
return NULL;
/* -------------------------------------------------------------------- */
/* Confirm the requested access is supported. */
/* -------------------------------------------------------------------- */
if( poOpenInfo->eAccess == GA_Update )
{
CPLError( CE_Failure, CPLE_NotSupported,
"The JDEM driver does not support update access to existing"
" datasets.\n" );
return NULL;
}
/* Check that the file pointer from GDALOpenInfo* is available */
if( poOpenInfo->fpL == NULL )
{
return NULL;
}
/* -------------------------------------------------------------------- */
/* Create a corresponding GDALDataset. */
/* -------------------------------------------------------------------- */
JDEMDataset *poDS;
poDS = new JDEMDataset();
/* Borrow the file pointer from GDALOpenInfo* */
poDS->fp = poOpenInfo->fpL;
poOpenInfo->fpL = NULL;
/* -------------------------------------------------------------------- */
/* Read the header. */
/* -------------------------------------------------------------------- */
VSIFReadL( poDS->abyHeader, 1, 1012, poDS->fp );
poDS->nRasterXSize = JDEMGetField( (char *) poDS->abyHeader + 23, 3 );
poDS->nRasterYSize = JDEMGetField( (char *) poDS->abyHeader + 26, 3 );
if (poDS->nRasterXSize <= 0 || poDS->nRasterYSize <= 0 )
{
CPLError( CE_Failure, CPLE_AppDefined,
"Invalid dimensions : %d x %d",
poDS->nRasterXSize, poDS->nRasterYSize);
delete poDS;
return NULL;
}
/* -------------------------------------------------------------------- */
/* Create band information objects. */
/* -------------------------------------------------------------------- */
poDS->SetBand( 1, new JDEMRasterBand( poDS, 1 ));
/* -------------------------------------------------------------------- */
/* Initialize any PAM information. */
/* -------------------------------------------------------------------- */
poDS->SetDescription( poOpenInfo->pszFilename );
poDS->TryLoadXML();
/* -------------------------------------------------------------------- */
/* Check for overviews. */
/* -------------------------------------------------------------------- */
poDS->oOvManager.Initialize( poDS, poOpenInfo->pszFilename );
return( poDS );
}
