if you correctly implemented the code in previous posts, you will be able to get start and end index of the selection in OnSelTouchEnd method (PDFView class).
The current implementation get the selection's rect with [vpage GetSelRect], but you can use getStartIndex and getEndtIndex (explained in previous posts) to get indexes.
To get the PDFVPage instance of the selected text, you can use [m_view vGetPage:m_cur_page] as OnSelTouchEnd method already does.
If it could help. you can also edit the OnSelEnd delegate method and add start and end index of the selection, to retrieve these informations in RDPDFViewController.
You can add this code in OnSelTouchEnd implementation:
int start = [vpage GetSelStartIndex];
int end = [vpage GetSelEndIndex];
then edit OnSelEnd in this way:
- (void)OnSelEnd:(float)x1 :(float)y1 :(float)x2 :(float)y2 :(int)start :(int)end;