LibTiff Mailing List
TIFF and LibTiff Mailing List Archive
November 2006
Previous Thread
Next Thread
Previous by Thread
Next by Thread
Previous by Date
Next by Date
Contact
The TIFF Mailing List Homepage
This list is run by Frank Warmerdam
Archive maintained by AWare Systems
Thread
2006.11.19 21:20 "Re: tiffinfo large file issue", by Bob Friesenhahn
On Sun, 19 Nov 2006, Paul Surgeon wrote: > On Sunday 19 November 2006 23:12, Frank Warmerdam wrote: >> Paul, >> >> My guess would be that it works on files where the directory data is >> before the 2GB mark. > > Hmmm ... I'm not sure what you mean. > Care to elaborate? The tiffinfo utility primarily reads TIFF directories, which may occur almost anywhere in the file. If the TIFF directory is placed at the end of a file which is over 2GB in size, then a file offet value bigger than 2GB is necessary to retrieve it. Systems which do not support large files often use a signed 32-bit integer value to represent file offsets (off_t type), and this value overflows at the 2GB offset. Some systems (e.g. Linux and Solaris) require special compilation options in order to use larger file offsets (signed 64-bit integer) in programs so that the programs can support large files. If all the offsets necessary to access the TIFF directories are less than 2GB, then it may be possible to usefully access the file even if the image raster data causes the file to be larger than 2GB. Bob ====================================== Bob Friesenhahn bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/