Le mercredi 20 juillet 2016 15:29:37, James Ramm a écrit : > The only 'fix' I can get working is to return a zero-filled array if the > call to VSIFReadL fails in IReadBlock. > > Given that ReadBlock checks whether the block index is valid, I think it is > safe to assume that if IReadBlock is called, the data is expected to be > retrievable (i.e. VSIFReadL in IReadBlock would not fail due to a user > requesting a block that is out of bounds as that raise an error much > earlier), is it acceptable to do this? > > Any reason for VSIFReadL to fail for a valid block index where an error > would be preferable to a zero'd array?
If the file is corrupted/truncated, it might be appropriate to return an error. Or if the operating system doesn't manage to read the block (disk corruption) I still don't get why VSIFTruncateL() wouldn't do the job. Are you sure you are computing correctly the file size when extending it ? > > I also tried to see whether VSIGetRangeStatusL could be of any help. > Interestingly, for the newly created raster (without any data added), it > returns VSI_RANGE_STATUS_DATA for the very first block and > VSI_RANGE_STATUS_HOLE > for subsequent blocks. The granularity of the information is linked a disk sector (4 KB ? might depend on the filesystem) so it is not surprising that the first block returns DATA given there's an header. > > On 14 July 2016 at 13:26, Even Rouault <[email protected]> wrote: > > Le jeudi 14 juillet 2016 13:07:42, jramm a écrit : > > > I added the following to the end of the Create method in > > > > > > frmts/northwood/grddataset.cpp: > > > vsi_l_offset nFileSize = 1024 + nXSize * nYSize * 2; > > > > --> beware of the potential int32 overflow in nXSize * nYSize > > > > > if (VSIFTruncateL(poDS->fp, nFileSize) != 0) { > > > > > > CPLError(CE_Failure, CPLE_FileIO, > > > > > > "Failed to allocate space for GRD file"); > > > > > > delete poDS; > > > return NULL; > > > > > > } > > > poDS->FlushCache(); // Write the header to disk. > > > > > > Unfortunately still receiving the error. I wonder if it would be better > > > > if > > > > > I explicitly write the zeros with VSIFWriteL? > > > > No, that's what VSIFTruncateL() is supposed to do, in a smarter way > > depending > > on filesystem capabilities. > > > > > -- > > > > > View this message in context: > > http://osgeo-org.1560.x6.nabble.com/Error-in-GDALWarp-to-NWT-GRD-tp527613 > > 6 > > > > > p5276347.html Sent from the GDAL - Dev mailing list archive at > > > > Nabble.com. > > > > > _______________________________________________ > > > gdal-dev mailing list > > > [email protected] > > > http://lists.osgeo.org/mailman/listinfo/gdal-dev > > > > -- > > Spatialys - Geospatial professional services > > http://www.spatialys.com -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
