CPLErr ELASRasterBand::IWriteBlock( int nBlockXOff, int nBlockYOff,
void * pImage )
{
ELASDataset *poGDS = (ELASDataset *) poDS;
CPLErr eErr = CE_None;
long nOffset;
int nDataSize;
CPLAssert( nBlockXOff == 0 );
CPLAssert( eAccess == GA_Update );
nDataSize = GDALGetDataTypeSize(eDataType) * poGDS->GetRasterXSize() / 8;
nOffset = poGDS->nLineOffset * nBlockYOff + 1024 + (nBand-1) * nDataSize;
if( VSIFSeek( poGDS->fp, nOffset, SEEK_SET ) != 0
|| VSIFWrite( pImage, 1, nDataSize, poGDS->fp ) != (size_t) nDataSize )
{
CPLError( CE_Failure, CPLE_FileIO,
"Seek or write of %d bytes at %ld failed.\n",
nDataSize, nOffset );
eErr = CE_Failure;
}
return eErr;
}
CPLErr ELASRasterBand::IReadBlock( int nBlockXOff, int nBlockYOff,
void * pImage )
{
ELASDataset *poGDS = (ELASDataset *) poDS;
CPLErr eErr = CE_None;
long nOffset;
int nDataSize;
CPLAssert( nBlockXOff == 0 );
nDataSize = GDALGetDataTypeSize(eDataType) * poGDS->GetRasterXSize() / 8;
nOffset = poGDS->nLineOffset * nBlockYOff + 1024 + (nBand-1) * nDataSize;
/* -------------------------------------------------------------------- */
/* If we can't seek to the data, we will assume this is a newly */
/* created file, and that the file hasn't been extended yet. */
/* Just read as zeros. */
/* -------------------------------------------------------------------- */
if( VSIFSeek( poGDS->fp, nOffset, SEEK_SET ) != 0
|| VSIFRead( pImage, 1, nDataSize, poGDS->fp ) != (size_t) nDataSize )
{
CPLError( CE_Failure, CPLE_FileIO,
"Seek or read of %d bytes at %ld failed.\n",
nDataSize, nOffset );
eErr = CE_Failure;
}
return eErr;
}