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2006.09.22 03:56 "Re: TIFF file bigger than 2Go (Pallek, Bernie: #CIPO - OPIC)", by Graeme Gill
Phil Harvey wrote:
> The application I'm developing can't seek past 2GB in a file because the
> seek() library function takes a signed 4-byte integer. I think this is
> a common problem. I can read larger files (so a >4GB JPEG image isn't a
> problem for instance), but due to the TIFF structure, you have to be
> able to seek to an arbitrary point in the file. So the limit is 2GB.
> Placing IFD0 first would help, but any data starting after the 2GB point
> still couldn't be read.
It seems like you might be able to create a fake "seek to unsigned 32 bit offset"
function by doing a signed SEEK_SET to 2G, followed by a SEEK_CUR of the next 2G ?
ie., something like:
int fuseek(FILE *fp, unsigned long offset) {
int rv;
unsigned long offset;
if (offset > LONG_MAX) {
if ((rv = fseek(fp, LONG_MAX, SEEK_SET)) != 0)
return rv;
return fseek(fp, offset - LONG_MAX, SEEK_CUR);
} else
return fseek(fp, offset, SEEK_SET);
}
(although note this doesn't handle the one case where offset = ULONG_MAX)
Graeme Gill.