Folks, I have implemented a new VSI driver allowing subregions of any file to be treated as a file object. The syntax is:
/vsisubfile/<offset>_<size>,<filename> So, for instance, to read a jpeg2000 datastream in a file named /data/abc.ntf with the data stream starting at byte 1000 and being 5000 bytes long you would use: /vsisubfile/1000_5000,/data/abc.ntf The primary goal of this was allowing the JP2MrSID driver to be used to read jpeg2000 data from NITF files. To that end I have modified the NITF driver in trunk to use this syntax instead of the J2K_SUBFILE: syntax that was used previously, and depended on special handling in each jpeg2000 driver. I also discovered a couple quirks in the mrsid driver - in particular with the custom stream implementation that had been making it's use fail in some cases with the v7 MrSID SDK. I have corrected those. It is now possible, in trunk, to read jpeg2000 nitf files with the MrSID driver. I have not yet confirmed the ECW and JP2KAK drivers are still working properly in this situation, but they ought to be since both supported VSI*L file streams. Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, [email protected] light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Programmer for Rent _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
