Dear Apache Devs: I believe that I have identified a bug in the creation of the (begin/end)bfrange operator used when embedding fonts with the PDCIDFontType2Embedder class.
The bug exists (as best I can tell) in both the main trunk and in the 2.0 branch. The code in question may be found here <https://github.com/ryanjackson-wf/pdfbox/blob/trunk/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/font/ToUnicodeWriter.java#L133-L136>. The portion of the PDF specification (version 1.7) that bears upon this code is Section 5.9, Example 5.16. The existing code attempts to limit the range logic to changes less than or equal to 255 code points, but it fails to account for at least the following situation by allowing this (for example): [srcCode1 srcCode2 dstString] 03FF 0400 0036 The overflow between srcCode1 and srcCode2 is not allowed by the specification and any text extraction will fail. The glyphs themselves render fine so it is not immediately obvious there is a problem until one tries to examine the text by using the Content Panel or by copy/pasting from Acrobat (Pro) to some other document. By contrast the following bfrange operator does allow the text extraction to work as intended: [srcCode1 srcCode2 dstString] 03FE 03FF 0035 Notice that no overflow exists, and as such the requirements of the specification are met. I've looked briefly at the PDFBOX project in Jira and have found the following tickets that may be caused by this same problem: PDFBOX-4785 <https://issues.apache.org/jira/browse/PDFBOX-4785> PDFBOX-5350 <https://issues.apache.org/jira/browse/PDFBOX-5350> I have put together a proposed solution here <https://github.com/ryanjackson-wf/pdfbox/pull/1> in my fork of the PDFBox GH mirror. With your permission I'd like to open a new Jira ticket for this and collaborate with whomever would like to help drive this work to get it reviewed and merged. I do have some open questions about how surrogates are to be handled. I'm also open to changes in the proposed code. Thank you for your time. Sincerely, Ryan Jackson Senior Software Engineer Workiva Inc.
