gibrish | generate fake words from real words | Data Manipulation library

The cause of this issue are invalid ToUnicode CMaps for all the fonts in the PDF: These CMaps may be valid for other uses but in the context of ToUnicode CMaps the PDF specification clearly restricts the data which may occur in this kind of CMap.

One can enable iText, though, to make sense out of this by a small patch.

The ToUnicode CMaps in the document are invalid in particular as they use begincidrange ... endcidrange sections for mapping the character codes instead of beginbfrange ... endbfrange and beginbfchar ... endbfchar sections as required here by the specification.

By chance iText does process ~cidrange sections in ToUnicode CMaps just like ~bfrange sections. (Well, not really by chance but because the class for processing ToUnicode CMaps extends an abstract base class for processing arbitrary CMaps.)

Unfortunately, though, ~cidrange ranges have an integer destination start value (e.g. <0003> <0003> 32) while ~bfrange ranges in ToUnicode CMaps must have hex string destination start values (e.g. <0000><005E><0020>). As a result parsing these ToUnicode CMaps with ~cidrange ranges in iText fails with an exception, leaving behind a map without entries. The result is that none of the character codes in the document can be mapped to anything sensible and all text is extracted as replacement characters ('�').

An obvious approach to fix this is by enabling the code processing the ranges to also handle integer destination start values, not only hex string values.

With that fix applied most of the characters can be extracted properly. You merely have to deal with the wrong order of RTL script text.

(I tested only the Java version but the .Net version should work, too.)

In the com.itextpdf.io.font.cmap.CMapToUnicode class (com.itextpdf.io artifact) the following method is called to add mappings derived from ranges: