[jira] [Created] (PDFBOX-3093) Exception in TTFParser

["Timur Kamalov (JIRA)" <ji...@apache.org>]

Timur Kamalov created PDFBOX-3093:
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             Summary: Exception in TTFParser
                 Key: PDFBOX-3093
                 URL: https://issues.apache.org/jira/browse/PDFBOX-3093
             Project: PDFBox
          Issue Type: Bug
            Reporter: Timur Kamalov
         Attachments: Skipping_font_tables_with_zero_length_.patch, resfont.ttf

The reason for this is an ambiguity in the TrueType specification. Namely, one of the font tables (OS/2) is present in the font directory with length 0. The specification itself is completely silent about this. 

The only other information I was able to find is:
- the FreeType font library (http://www.freetype.org/freetype2/docs/reference/ft2-truetype_tables.html#FT_Sfnt_Table_Info) assumes that any table having 0 length in the font directory is treated as missing.
- Google OpenType Sanitizer would report an error in such situation: https://github.com/khaledhosny/ots/blob/master/src/ots.cc, lines 575-578
- there are several related discussions at Adobe forums: https://forums.adobe.com/thread/1616317 , https://forums.adobe.com/thread/1611899

 As allowing zero length tables in TrueType fonts seems to be quite logical (and also implicitly confirmed by Adobe Acrobat validator), I've changed the TTFParser to skip tables with 0 length.

Attaching patch and font file. Will add test file also if necessary.



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