%File: footnotebackref.sty
% Copyright (C) 2012 Holger Lange
%
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3
% of this license or (at your option) any later version.
% The latest version of this license is in
%   http://www.latex-project.org/lppl.txt
% and version 1.3 or later is part of all distributions of LaTeX
% version 2005/12/01 or later.

\NeedsTeXFormat{LaTeX2e}[2011/06/27]
\ProvidesPackage{footnotebackref}%
    [2012/07/01 v1.0 Backreferences for footnotes (Holger Lange)]

% This package was inspired by http://tex.stackexchange.com/a/40282

\RequirePackage{letltxmacro}
\RequirePackage{hyperref}
\RequirePackage{kvoptions}[2010/12/23]% v3.10

\SetupKeyvalOptions{family=FootnoteBackref, prefix=FootnoteBackref@}

% The symbol between the footnotenumber and the footnotetext
% If empty no symbol will be printed
\DeclareStringOption{symbol}

% Option to hyperlink the footnotenumber
\DeclareBoolOption[true]{numberlinked}
\ProcessKeyvalOptions*

% A new counter to create an unambiguous label-tag for all hyperfootnotes
\newcounter{BackrefHyperFootnoteCounter}

% Store the original LaTeX footnote macros to separate macros
\LetLtxMacro{\BHFN@OldFootnote}{\footnote}
\LetLtxMacro{\BHFN@OldMakefntext}{\@makefntext}

% Redefine the original footnote macro to
% branch between the footnote with/without optional argument
\renewcommand*\footnote{%
    \refstepcounter{BackrefHyperFootnoteCounter}%
    \edef\BackrefFootnoteTag{bhfn:\theBackrefHyperFootnoteCounter}%
    \label{\BackrefFootnoteTag}%
    \@ifnextchar[\Backref@OptHyperFootnote\Backref@HyperFootnote}

% Define an new footnote without optional argument
\newcommand\Backref@HyperFootnote[1]{%
    \BHFN@OldFootnote{\Backref@HyperSymbol#1}}

% Define an new footnote with optional argument
\newcommand\Backref@OptHyperFootnote[2][\empty]{%
    \BHFN@OldFootnote[#1]{\Backref@HyperSymbol#2}}

% Definition of the hyperlinked symbol ...
\newcommand\Backref@HyperSymbol{%
    \hyperref[\BackrefFootnoteTag]{\FootnoteBackref@symbol}}

% ...but if the symbol is empty it is deleted straightaway
\ifx\FootnoteBackref@symbol\empty
    \renewcommand\Backref@HyperSymbol\relax\fi

% If the footnote number should be the reference
% than redefine the \@makefntext and \@makefnmark
% The \@makefnmark macro is redefined in the space of
% the \@makefntext macro
% So the footnote numbers in the main text are not influenced
\ifFootnoteBackref@numberlinked
    \renewcommand\@makefntext[1]{%
        \renewcommand\@makefnmark{%
            \mbox{\textsuperscript{\normalfont%
            \hyperref[\BackrefFootnoteTag]{\@thefnmark}}}\,}%
        \BHFN@OldMakefntext{#1}}%
\fi

\endinput
