AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

2005.08.05 14:03 "[Tiff] DateTime field length", by Ville Herva

I noticed Developer's Image Library (http://openil.sorceforge.net) writes too much data to the TIFF DateTime field. Developer's Image Library uses libtiff, and when I upgraded libtiff to 3.7.3, it began to complain:

TIFFMemFile incorrect count for field "DateTime" (21, expecting 20); tag trimmed

This happens when an image saved with DevIl+libtiff is being opened with DevIl+libtiff.

Now, DevIl writes way too much to the DateTime field - I understand the field is limited to 20 chars (including NUL) in TIFF. But would it make sense to make libtiff truncate the excess bytes when writing (and/or warn about it) so that it wouldn't produce tiff files it'll complain about when opening them?

As for DevIl, something like this is probably needed:

--- ../orig/DevIL-1.6.7/src-IL/src/il_tiff.c    2004-05-12 22:45:16.000000000 +0300

+++ src-IL/src/il_tiff.c        2005-08-05 11:41:04.239343300 +0300

@@ -808,7 +852,10 @@ char *iMakeString()
 #endif
        CurTime = localtime(&Time);

-       strftime(TimeStr, 255, "%s (%z)", CurTime); // "%#c (%z)"       // %s wa

s %c

+       strftime(TimeStr, 255, "%H:%M:%S %d.%m.%Y (%z)", CurTime); // "%#c (%z)"
        // %s was %c
+
+       // The TIFF DATETIME field is max 20 chars, unfortunately.
+       TimeStr[19] = '\0';

        return TimeStr;
 }

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