Return the bidirectional embedding levels of the input paragraph.
The bidirectional embedding levels are defined by the [Unicode Bidirectional Algorithm](http://www.unicode.org/reports/tr9/).
If the input base direction is a weak direction, the direction of the characters in the text will determine the final resolved direction.
| text |
the text to itemize. |
| length |
the number of bytes (not characters) to process, or -1 if |
| pbase_dir |
input base direction, and output resolved direction. |
|
a newly allocated array of embedding levels, one item per character (not byte), that should be freed using [[email protected]]. |