%%
%% This is file `flushend.sty',
%% generated with the docstrip utility.
%%
%% The original source files were:
%%
%% flushend.dtx  (with options: `package')
%% 
%% Copyright (C) 1997-2017 by Sigitas Tolu\v{s}is <sigitas@vtex.lt>
%% VTeX Ltd., Mokslinink\k{u} 2a, Vilnius, Lithuania
%% http://www.vtex.lt/tex/download/macros/
%% --------------------------------------------------------------------------
%% 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.
%%
%% PURPOSE:   Balanced columns on last page in twocolumn mode.
%%
\NeedsTeXFormat{LaTeX2e}[1999/12/01]
\ProvidesPackage{flushend}
    [2017/03/27 v3.3 Balancing columns in twocolumn mode]
\newif\if@auto@baselineskip \@auto@baselineskiptrue
\newif\if@ancient@balance@version \@ancient@balance@versionfalse
\newif\if@right@column@spread \@right@column@spreadtrue
\newif\if@remove@lastbox@at@balancing \@remove@lastbox@at@balancingtrue
\newif\if@balance@debug \@balance@debugfalse
\DeclareOption{autobase}{\global\@auto@baselineskiptrue}
\DeclareOption{noautobase}{\global\@auto@baselineskipfalse}
\DeclareOption{ancient}{\global\@ancient@balance@versiontrue}
\DeclareOption{modern}{\global\@ancient@balance@versionfalse}
\DeclareOption{spread}{\global\@right@column@spreadtrue}
\DeclareOption{nospread}{\global\@right@column@spreadfalse}
\DeclareOption{removelastbox}{\global\@remove@lastbox@at@balancingtrue}
\DeclareOption{keeplastbox}{\global\@remove@lastbox@at@balancingfalse}
\DeclareOption{checkfootnote}{%
    \AtEndOfPackage{%
        \let\check@@footnoterule@@box\initial@check@@footnoterule@@box
        }%
    }
\DeclareOption{nocheckfootnote}{%
    \AtEndOfPackage{%
        \let\check@@footnoterule@@box\@gobblethree
        }%
    }
\DeclareOption{checkfloat}{%
    \AtEndOfPackage{%
        \let\top@@floatbox@min\top@@floatbox@min@default
        }%
    }
\DeclareOption{nocheckfloat}{%
    \AtEndOfPackage{%
        \let\top@@floatbox@min\maxdimen
        }%
    }
\DeclareOption{debug}{\global\@balance@debugtrue}
\DeclareOption{nodebug}{\global\@balance@debugfalse}
\ProcessOptions
\newskip\flushend@@lastskip@a
\newskip\flushend@@lastskip@b
\newskip\flushend@@lastskip@c
\newcount\flushend@@penalty@a
\newdimen\flushend@@lastkern@a
\newdimen\var@@temp@spread
\newdimen\var@@temp@a
\def\top@@skip@@limit{.7\topskip}
\newdimen\flushend@@page@rule \flushend@@page@rule\z@
\def\showcolsendrule{\global\flushend@@page@rule=.4\p@}
\gdef\top@@floatbox@min@default{4\topskip}
\let\top@@floatbox@min\top@@floatbox@min@default
\newbox\flushend@@varbox@a
\newbox\flushend@@varbox@c
\newbox\flushend@@tempbox@a
\newbox\flushend@@tempbox@c
\@ifundefined{@viper}{\newbox\@viper}{}
\@ifundefined{hold@viper}{\newbox\hold@viper}{}
\newtoks\atColsBreak \atColsBreak={}
\newtoks\atColsEnd   \atColsEnd={}
\@ifundefined{fmt@box@adds}{\def\fmt@box@adds#1{#1}}{}
\@ifundefined{fmt@vbox@adds}{\def\fmt@vbox@adds[#1]#2{#2}}{}
\def\unskip@three@kern@penalty{%
    \unskip\unkern\unpenalty
    \unskip\unkern\unpenalty
    \unskip\unkern\unpenalty
    }
\gdef\remove@lastbox@at@balancing{%
    \unskip@three@kern@penalty
    \if@remove@lastbox@at@balancing
    \else
        \expandafter\null
    \fi
    \bgroup
        \setbox\z@\lastbox
        \ifdim\wd\z@>\z@
            \box\z@
        \else
            \aftergroup\unskip@three@kern@penalty
        \fi
    \egroup
    }
\def\set@split@topskip@to#1{%
    \splittopskip#1\relax \vfuzz\maxdimen \vbadness\maxdimen
    }
\def\show@@box#1{%
    \bgroup
        \showboxbreadth=20000\showboxdepth=20000%
        \showbox#1\relax
    \egroup
    }
\def\wlog@balance@debug#1{\if@balance@debug \wlog{#1}\fi}
\def\log@box@info#1{<box\the#1>(\the\ht#1+\the\dp#1)x\the\wd#1}
\let\show@@box@next\@gobble
\gdef\analyze@lastbox@box#1{%
    \setbox\flushend@@varbox@a\vbox{%
        \unvbox#1%
        \global\flushend@@lastskip@a\lastskip
        \unskip
        \global\var@@temp@a\lastkern
        \unkern
        \global\flushend@@penalty@a\lastpenalty
        \unpenalty
        \ifdim\lastskip>\z@
            \global\flushend@@lastskip@a\lastskip
        \fi
        \unskip
        \ifdim\lastkern>\z@
            \global\var@@temp@a\lastkern
        \fi
        \unkern
        \ifnum\lastpenalty>\z@
            \global\flushend@@penalty@a\lastpenalty
        \fi
        \unpenalty
        \global\setbox\flushend@@tempbox@a\lastbox
        }%
    \wlog@balance@debug{^^J::analyze@lastbox@box::\log@box@info{#1}%
                        ^^J ::unvbox: \log@box@info{\flushend@@varbox@a}%
                        ^^J::lastbox: \log@box@info{\flushend@@tempbox@a}%
                        ^^J::lastskip: \the\flushend@@lastskip@a;
                            lastkern: \the\var@@temp@a;
                         lastpenalty: \the\flushend@@penalty@a
                       }%
    }
\gdef\analyze@leftcolumn@box#1{%
    \set@split@topskip@to\z@
    \flushend@@lastskip@b\ht#1%
    \wlog@balance@debug{^^Jmainbox: \log@box@info{#1}}%
    \setbox\flushend@@varbox@a\vbox{%
        \unvbox#1%
        \global\flushend@@lastskip@a\lastskip
        \unskip
        \global\flushend@@lastkern@a\lastkern
        \unkern
        \global\flushend@@penalty@a\lastpenalty
        \unpenalty
        \global\setbox\flushend@@tempbox@a\lastbox
        }%
    \advance\flushend@@lastskip@b -\ht\flushend@@varbox@a
    \advance\flushend@@lastskip@b -\ht\flushend@@tempbox@a
    \wlog@balance@debug{.-box: \log@box@info{\flushend@@varbox@a}%
                 ^^J.-lastbox: \log@box@info{\flushend@@tempbox@a}%
                ^^J.-lastskip: \the\flushend@@lastskip@a;
                     lastkern: \the\flushend@@lastkern@a;
                  lastpenalty: \the\flushend@@penalty@a
                    ^^J.-diff: \the\flushend@@lastskip@b
        }%
    \check@@footnoterule@@box\flushend@@tempbox@a\flushend@@lastskip@b\flushend@@varbox@a
    \check@@baselineskip@@skip
        \flushend@@lastskip@a
        \flushend@@lastskip@b
        \flushend@@lastskip@c
    \ifx\check@@footnoterule@@box\check@@baselineskip@@skip
    \else
        \ifvoid\flushend@@tempbox@a
            \ifdim\ht\flushend@@varbox@a>\topskip
                \flushend@@lastskip@b\ht\flushend@@varbox@a
                \var@@temp@a\ht\flushend@@varbox@a
                \loop
                    \setbox\flushend@@tempbox@c\vsplit\flushend@@varbox@a to\var@@temp@a
                    \ifvoid\flushend@@varbox@a
                        \setbox\flushend@@varbox@a\vbox{\unvbox\flushend@@tempbox@c}%
                        \advance \var@@temp@a -3\p@
                    \else
                        \var@@temp@a=-1\p@
                    \fi
                \ifdim \var@@temp@a>\z@
                \repeat
                \setbox\flushend@@varbox@a\vbox{\unvbox\flushend@@varbox@a}%
                \setbox\flushend@@tempbox@c\vbox{\unvbox\flushend@@tempbox@c}%
                \advance\flushend@@lastskip@b -\ht\flushend@@varbox@a
                \advance\flushend@@lastskip@b -\ht\flushend@@tempbox@c
                \wlog@balance@debug{..--box: \log@box@info{\flushend@@tempbox@c}%
                             ^^J..--lastbox: \log@box@info{\flushend@@varbox@a}%
                                ^^J..--diff: \the\flushend@@lastskip@b
                    }%
                \check@@footnoterule@@box\flushend@@varbox@a\flushend@@lastskip@b
                    \flushend@@tempbox@c
                \check@@baselineskip@@skip\flushend@@lastskip@a\flushend@@lastskip@b
                    \flushend@@lastskip@c
                \ifx\check@@footnoterule@@box\check@@baselineskip@@skip
                \else
                    \ifdim\ht\flushend@@varbox@a>.5\topskip
                        \analyze@lastbox@box\flushend@@varbox@a
                    \fi
                    \setbox\flushend@@varbox@a\vbox{\unvbox\flushend@@tempbox@c}%
                \fi
            \else
                \wlog@balance@debug{lastbox: \log@box@info{\flushend@@varbox@a}}%
            \fi
        \fi
        \ifdim\ht\flushend@@varbox@a>\topskip
            \expandafter\analyze@leftcolumn@box\expandafter\flushend@@varbox@a
        \fi
    \fi
    }
\def\get@@footnoterule@@box{%
    \set@split@topskip@to\z@
    \setbox\flushend@@varbox@a\vbox{\strut
        \vskip\z@
        \footnoterule
        \unskip\unkern\unpenalty
        \unskip\unkern\unpenalty
        }%
    \setbox\flushend@@tempbox@c\vsplit\flushend@@varbox@a to\p@
    \xdef\footnoterule@@box@@ht{\the\ht\flushend@@varbox@a}%
    \xdef\footnoterule@@box@@dp{\the\dp\flushend@@varbox@a}%
    \xdef\footnoterule@@box@@wd{\the\wd\flushend@@varbox@a}%
    \wlog@balance@debug{:footnoterule: \log@box@info{\flushend@@varbox@a}}%
    \setbox\flushend@@tempbox@c\vbox{\unvbox\flushend@@varbox@a}%
    }
\long\def\@gobblethree#1#2#3{}
\def\check@@footnoterule@@box#1#2#3{%
    \ifdim\ht#1=\footnoterule@@box@@ht
        \ifdim\dp#1=\footnoterule@@box@@dp
            \ifdim\wd#1=\footnoterule@@box@@wd
                \ifdim#2=\topskip
                \else
                    \xdef\main@box@height{\the\ht#3}%
                    \xdef\main@box@skip{\the#2}%
                    \wlog@balance@debug{^^J:footnoterule found:
                                        main@box <ht=\main@box@height,
                                        skip=\main@box@skip>
                                       }%
                    \global\let\check@@footnoterule@@box\@gobblethree
                    \global\let\check@@baselineskip@@skip\reset@check@@baselineskip@@skip
                \fi
            \fi
        \fi
    \fi
    }
\let\initial@check@@footnoterule@@box\check@@footnoterule@@box
\def\check@@baselineskip@@skip#1#2#3{%
    \ifdim#1>\z@
        \ifdim#2>\z@
            \global#3=\the#1%
            \global\let\check@@baselineskip@@skip\@gobblethree
        \fi
    \fi
    }
\let\initial@check@@baselineskip@@skip\check@@baselineskip@@skip
\def\reset@check@@baselineskip@@skip#1#2#3{%
    \global#3=\z@
    \global\let\check@@baselineskip@@skip\initial@check@@baselineskip@@skip
    }
\def\analyze@rightcolumn@box#1{%
    \bgroup
        \xdef\top@@floatbox@ht{\z@}%
        \xdef\top@@floatbox@skip{\z@}%
        \xdef\top@@section@skip{\z@}%
        \set@split@topskip@to\z@
        \setbox\flushend@@varbox@a\vbox{\strut
            \vskip\z@
            \unvcopy#1%
            }%
        \setbox\flushend@@tempbox@c\vsplit\flushend@@varbox@a to\p@
        \wlog@balance@debug{^^J(R)mainbox: \log@box@info{#1}}%
        \flushend@@lastskip@a\ht\flushend@@varbox@a
        \advance\flushend@@lastskip@a\dp\flushend@@varbox@a
        \ifdim\flushend@@lastskip@a>\z@
            \analyze@nonempty@rightcolumn@box
        \fi
    \egroup
    }
\def\analyze@nonempty@rightcolumn@box{%
    \bgroup
        \var@@temp@a3\p@
        \loop
            \flushend@@lastskip@b\ht\flushend@@varbox@a
            \advance\flushend@@lastskip@b\dp\flushend@@varbox@a
            \setbox\flushend@@tempbox@c\vsplit\flushend@@varbox@a to\var@@temp@a
            \ifvoid\flushend@@tempbox@c
                \advance \var@@temp@a 3\p@
                \ifdim\var@@temp@a>\flushend@@lastskip@b
                    \var@@temp@a=-1\p@
                \fi
            \else
                \setbox\flushend@@tempbox@c\vbox{\unvbox\flushend@@tempbox@c}%
                \ifdim\ht\flushend@@tempbox@c>\top@@floatbox@min
                    \advance\flushend@@lastskip@b -\ht\flushend@@tempbox@c
                    \advance\flushend@@lastskip@b -\dp\flushend@@tempbox@c
                    \advance\flushend@@lastskip@b -\ht\flushend@@varbox@a
                    \advance\flushend@@lastskip@b -\dp\flushend@@varbox@a
                    \xdef\top@@floatbox@skip{\the\flushend@@lastskip@b}%
                    \flushend@@lastskip@b\flushend@@lastskip@a
                    \advance\flushend@@lastskip@b -\ht\flushend@@varbox@a
                    \advance\flushend@@lastskip@b -\top@@floatbox@skip
                    \xdef\top@@floatbox@ht{\the\flushend@@lastskip@b}%
                    \var@@temp@a=3\p@
                \else
                    \advance\flushend@@lastskip@b -\ht\flushend@@tempbox@c
                    \advance\flushend@@lastskip@b -\dp\flushend@@tempbox@c
                    \advance\flushend@@lastskip@b -\ht\flushend@@varbox@a
                    \advance\flushend@@lastskip@b -\dp\flushend@@varbox@a
                    \ifdim\ht\flushend@@tempbox@c>\topskip
                    \else
                        \xdef\top@@section@skip{\the\flushend@@lastskip@b}%
                    \fi
                    \var@@temp@a=-1\p@
                \fi
            \fi
        \ifdim \var@@temp@a>\z@
        \repeat
        \ifvoid\flushend@@tempbox@c
        \else
            \ifdim\top@@section@skip>\z@
            \else
                \ifdim\ht\flushend@@tempbox@c>\z@
                    \setbox\flushend@@varbox@a\vbox{\unvbox\flushend@@tempbox@c}%
                \fi
                \flushend@@lastskip@b\ht\flushend@@varbox@a
                \var@@temp@a=3\p@
                \loop
                    \setbox\flushend@@tempbox@c\vsplit\flushend@@varbox@a to\var@@temp@a
                    \ifvoid\flushend@@tempbox@c
                        \advance \var@@temp@a 3\p@
                        \ifdim\var@@temp@a>\flushend@@lastskip@b
                            \var@@temp@a=-1\p@
                        \fi
                    \else
                        \ifdim\ht\flushend@@tempbox@c<\z@
                        \else
                            \var@@temp@a=-1\p@
                        \fi
                    \fi
                \ifdim \var@@temp@a>\z@
                \repeat
                \loop
                    \setbox\flushend@@varbox@a\vbox{%
                        \unvbox\flushend@@tempbox@c
                        \unskip\unkern\unpenalty
                        \unskip\unkern\unpenalty
                        \unskip\unkern\unpenalty
                        \setbox\flushend@@tempbox@c\lastbox
                        }%
                    \flushend@@lastskip@b\ht\flushend@@varbox@a
                    \setbox\flushend@@varbox@a\vbox{%
                        \unvbox\flushend@@varbox@a
                        \unskip\unkern\unpenalty
                        \unskip\unkern\unpenalty
                        \unskip\unkern\unpenalty
                        }%
                    \advance\flushend@@lastskip@b -\ht\flushend@@varbox@a
                    \ifdim\flushend@@lastskip@b>\topskip
                        \xdef\top@@section@skip{\the\flushend@@lastskip@b}%
                    \fi
                \ifdim\ht\flushend@@varbox@a>2\topskip
                    \setbox\flushend@@tempbox@c\vbox{\unvbox\flushend@@varbox@a}%
                \repeat
            \fi
        \fi
    \egroup
    }
\def\combine@columns@for@balance{%
    \setbox\@outputbox\vbox{\strut
        \vskip\z@
        \unvbox\@outputbox
        }%
    \set@split@topskip@to\z@
    \setbox\flushend@@tempbox@c\vsplit\@outputbox to\p@
    \if@auto@baselineskip
        %% Trying guess baselineskip value on column break
        \ifdim\top@@floatbox@skip>\z@
            \setbox\flushend@@tempbox@c\vsplit\@outputbox to\top@@floatbox@ht
            \setbox\flushend@@tempbox@c\vbox{\unvbox\flushend@@tempbox@c}%
        \fi
        \setbox\@tempboxa\vbox{%
            \unvbox\flushend@@varbox@a
            \unskip\unkern\unpenalty
            \vskip\flushend@@lastskip@c
            \the\atColsBreak
            \hrule\@height\flushend@@page@rule width\columnwidth
            \ifdim\top@@section@skip>\top@@skip@@limit
                \vskip\top@@section@skip
            \fi
            \unvbox\@outputbox
            \remove@lastbox@at@balancing
            \the\atColsEnd
            }%
        \ifdim\top@@floatbox@skip>\z@
            \setbox\@outputbox\vbox{\unvbox\flushend@@tempbox@c}%
        \fi
    \else
        %% Ignore baselineskip value on column break
        \setbox\@tempboxa\vbox{%
            \unvbox\@leftcolumn
            \setbox\z@\lastbox
            \unskip\unkern\unpenalty
            \the\atColsBreak
            \hrule\@height\flushend@@page@rule width\columnwidth
            \unvbox\@outputbox
            \remove@lastbox@at@balancing
            \the\atColsEnd
            }%
    \fi
    }
\def\set@outputbox@with@footnote{%
    %% footnote in left column
    \@tempdimb\ht\@tempboxa
    \ifdim\top@@floatbox@skip>\z@
        \advance\@tempdimb \top@@floatbox@skip
        \advance\@tempdimb \top@@floatbox@ht
    \fi
    \advance\@tempdimb \main@box@skip
    \advance\@tempdimb \ht\@leftcolumn
    \@tempdimb .5\@tempdimb
    \advance\@tempdimb -\main@box@skip
    \advance\@tempdimb -\ht\@leftcolumn
    \set@split@topskip@to\topskip
    \loop
        \setbox\flushend@@varbox@a\copy\@tempboxa
        \setbox\flushend@@tempbox@a\vsplit\flushend@@varbox@a to\@tempdimb
        \setbox\flushend@@tempbox@c\vbox{\unvcopy\flushend@@tempbox@a}%
        \ifdim\top@@floatbox@skip>\z@
        \setbox\flushend@@varbox@c\vbox{%
                \unvcopy\@outputbox
                \vskip\top@@floatbox@skip
                \unvbox\flushend@@varbox@a
                }%
        \else
            \setbox\flushend@@varbox@c\vbox{\unvbox\flushend@@varbox@a}%
        \fi
        \var@@temp@spread=\ht\flushend@@tempbox@c
        \advance\var@@temp@spread by\dp\flushend@@tempbox@c
        \advance\var@@temp@spread \main@box@skip
        \advance\var@@temp@spread \ht\@leftcolumn
        \advance\var@@temp@spread by-\ht\flushend@@varbox@c
        \advance\var@@temp@spread by-\dp\flushend@@varbox@c
        \wlog@balance@debug{Left x: \the\ht\flushend@@tempbox@a
                            +\the\dp\flushend@@tempbox@a=\the\ht\flushend@@varbox@a
                            +\the\dp\flushend@@varbox@a::\the\@tempdimb
                            ^^JLeft 0: \the\ht\flushend@@tempbox@c
                            +\the\dp\flushend@@tempbox@c::\the\@tempdimb
                            ^^JRight x: \the\ht\flushend@@varbox@c
                            +\the\dp\flushend@@varbox@c=\the\ht\flushend@@varbox@a
                            +\the\dp\flushend@@varbox@a::\the\@tempdimb
                            ^^JExtra height:\the\var@@temp@spread\space when \the\@tempdimb
                            }%
    \ifdim\var@@temp@spread<\z@
        \advance\@tempdimb 1\p@
    \repeat
    \flushend@@lastskip@a\the\ht\flushend@@tempbox@c
    \advance\flushend@@lastskip@a \main@box@skip
    \advance\flushend@@lastskip@a \ht\@leftcolumn
    \flushend@@lastskip@b\the\@tempdimb
    \setbox\flushend@@tempbox@a\vsplit\@tempboxa to\@tempdimb
    \setbox\@leftcolumn\vbox to\@tempdima{%
        \vbox to \flushend@@lastskip@a{%
            \unvbox\flushend@@tempbox@a
            \vskip\main@box@skip
            \unvbox\@leftcolumn
            \vss
            }%
        \hrule\@height\flushend@@page@rule width\textwidth
        \vss
        }%
    \global\ht\@leftcolumn=\the\@tempdima
    \wlog{- LAST -%
          ^^JExtra skip:\the\var@@temp@spread
          ^^JLeft:\the\ht\@leftcolumn/\the\dp\@leftcolumn
          ^^JRight:\the\ht\@tempboxa/\the\dp\@tempboxa
          ^^JOutput:\the\@tempdimb
          }%
    \ifdim\top@@floatbox@skip>\z@
        \setbox\@outputbox\vbox to\@tempdima{%
            \if@right@column@spread
                \vbox spread\var@@temp@spread{%
                    \unvbox\@outputbox
                    \vskip\top@@floatbox@skip
                    \unvbox\@tempboxa
                    }%
            \else
                \vbox spread\var@@temp@spread{%
                    \unvbox\@outputbox
                    \vskip\top@@floatbox@skip
                    \unvbox\@tempboxa
                    \vss
                    }%
            \fi
            \vss
            }%
    \else
        \setbox\@outputbox\vbox to\@tempdima{%
            \if@right@column@spread
                \vbox spread\var@@temp@spread{%
                    \unvbox\@tempboxa
                    }%
            \else
                \vbox spread\var@@temp@spread{%
                    \unvbox\@tempboxa
                    \vss
                    }%
            \fi
            \vss
            }%
    \fi
    }
\def\set@outputbox@without@footnote{%
    %% no footnote in left column
    \@tempdimb \ht\@tempboxa
    \ifdim\top@@floatbox@skip>\z@
        \advance\@tempdimb \top@@floatbox@skip
        \advance\@tempdimb \top@@floatbox@ht
    \fi
    \@tempdimb .5\@tempdimb
    \set@split@topskip@to\topskip
    \loop
        \setbox\flushend@@varbox@a\copy\@tempboxa
        \setbox\flushend@@tempbox@a\vsplit\flushend@@varbox@a to\@tempdimb
        \setbox\flushend@@tempbox@c\vbox{\unvcopy\flushend@@tempbox@a}%
        \ifdim\top@@floatbox@skip>\z@
            \setbox\flushend@@varbox@c\vbox{%
                \unvcopy\@outputbox
                \vskip\top@@floatbox@skip
                \unvbox\flushend@@varbox@a
                }%
        \else
            \setbox\flushend@@varbox@c\vbox{\unvbox\flushend@@varbox@a}%
        \fi
        \var@@temp@spread=\ht\flushend@@tempbox@c
        \advance\var@@temp@spread by\dp\flushend@@tempbox@c
        \advance\var@@temp@spread by-\ht\flushend@@varbox@c
        \advance\var@@temp@spread by-\dp\flushend@@varbox@c
        \wlog@balance@debug{Left x: \the\ht\flushend@@tempbox@a
                            +\the\dp\flushend@@tempbox@a=\the\ht\flushend@@varbox@a
                            +\the\dp\flushend@@varbox@a::\the\@tempdimb
                            ^^JLeft 0: \the\ht\flushend@@tempbox@c
                            +\the\dp\flushend@@tempbox@c::\the\@tempdimb
                            ^^JRight x: \the\ht\flushend@@varbox@c
                            +\the\dp\flushend@@varbox@c=\the\ht\flushend@@varbox@a
                            +\the\dp\flushend@@varbox@a::\the\@tempdimb
                            ^^JExtra height:\the\var@@temp@spread\space when \the\@tempdimb
                           }%
    \ifdim\var@@temp@spread<\z@ \advance\@tempdimb 1\p@ \repeat
    \wlog{- LAST -%
          ^^JExtra skip:\the\var@@temp@spread
          ^^JLeft:\the\ht\flushend@@tempbox@c/\the\dp\flushend@@tempbox@c
          ^^JRight:\the\ht\flushend@@varbox@c/\the\dp\flushend@@varbox@c
          ^^JOutput:\the\@tempdimb
          }%
    \setbox\flushend@@tempbox@c\vsplit\@tempboxa to\@tempdimb
    \setbox\flushend@@varbox@c\vbox{\unvbox\flushend@@tempbox@c}%
    \setbox\@leftcolumn\vbox to\@tempdima{%
        \vbox to\@tempdimb{\unvbox\flushend@@varbox@c\vss}%
        \hrule\@height\flushend@@page@rule width\textwidth
        \vss
        }%
    \global\ht\@leftcolumn=\the\@tempdima
    \ifdim\top@@floatbox@skip>\z@
        \setbox\@outputbox\vbox to\@tempdima{%
            \if@right@column@spread
                \vbox spread\var@@temp@spread{%
                    \unvbox\@outputbox
                    \vskip\top@@floatbox@skip
                    \unvbox\@tempboxa
                    }%
            \else
                \vbox spread\var@@temp@spread{%
                    \unvbox\@outputbox
                    \vskip\top@@floatbox@skip
                    \unvbox\@tempboxa
                    \vss
                    }%
            \fi
            \vss
            }%
    \else
        \setbox\@outputbox\vbox to\@tempdima{%
            \if@right@column@spread
                \vbox spread\var@@temp@spread{%
                    \unvbox\@tempboxa
                    }%
            \else
                \vbox spread\var@@temp@spread{%
                    \unvbox\@tempboxa
                    \vss
                    }%
            \fi
            \vss
            }%
    \fi
    }
\def\last@outputdblcol@modern{%
    \if@firstcolumn
        \global \@firstcolumnfalse
        \global \setbox\@leftcolumn \box\@outputbox
    \else
        \global \@firstcolumntrue
        \@tempdima\ht\@leftcolumn
        \set@split@topskip@to\topskip
        \var@@temp@spread=\wd\@outputbox
        \get@@footnoterule@@box
        \xdef\main@box@height{\the\ht\@leftcolumn}%
        \xdef\main@box@skip{\z@}%
        \global\flushend@@lastskip@c\z@
        \setbox\flushend@@varbox@a\vbox{\unvcopy\@leftcolumn}%
        \analyze@leftcolumn@box\flushend@@varbox@a
        \setbox\flushend@@varbox@a\vbox{\unvcopy\@outputbox}%
        \analyze@rightcolumn@box\flushend@@varbox@a
        \ifdim\main@box@skip>\z@
            %% footnote in left column
            \set@split@topskip@to\z@
            \setbox\flushend@@varbox@a\vsplit\@leftcolumn to\main@box@height
        \else
            %% no footnote in left column
            \setbox\flushend@@varbox@a\box\@leftcolumn
        \fi
        \ifdim\var@@temp@spread>\z@
            %% rightcolumn non empty
            \combine@columns@for@balance
       \else
            %% rightcolumn empty
            \setbox\@tempboxa\vbox{%
                \unvbox\flushend@@varbox@a
                \remove@lastbox@at@balancing
                \the\atColsEnd
                }%
       \fi
        \ifdim\main@box@skip>\z@
            %% footnote in left column
            \set@outputbox@with@footnote
        \else
            %% no footnote in left column
           \set@outputbox@without@footnote
        \fi
        \setbox\@outputbox \vbox {%
            \hb@xt@\textwidth {%
                \hb@xt@\columnwidth {%
                    \fmt@box@adds{\box\@leftcolumn}\hss}%
                    \hfil
                    \vrule \@width\columnseprule
                    \hfil
                    \hb@xt@\columnwidth {%
                        \fmt@box@adds{\box\@outputbox}\hss}%
                        }%
                    }%
        \global\let\@outputdblcol\saved@orig@@outputdblcol
        \global\atColsEnd{}%
        \ifvoid\hold@viper
        \else
            \setbox\@outputbox\vbox{\box\hold@viper\box\@outputbox}%
        \fi
        \@combinedblfloats
        \@outputpage
        \begingroup
            \@dblfloatplacement
            \@startdblcolumn
            \@whilesw\if@fcolmade\fi
                {\@outputpage\@startdblcolumn}%
            \ifvoid\@viper
            \else
                \global\setbox\@viper\vbox{%
                    \vskip-\stripsep
                    \unvbox\@viper
                    }%
                \csname @viperoutput\endcsname
            \fi
        \endgroup
    \fi
    }
\def\last@outputdblcol@ancient{%
    \if@firstcolumn
        \global\@firstcolumnfalse
        \global\setbox\@leftcolumn\box\@outputbox
    \else
        \global\@firstcolumntrue
        \@tempdima\ht\@leftcolumn
        \set@split@topskip@to\topskip
        \if@auto@baselineskip
            \setbox\@tempboxa\vbox{%
                \unvcopy\@leftcolumn
                \global\flushend@@lastskip@c\lastskip
                \global\flushend@@lastskip@b\lastskip
                \loop
                    \global\flushend@@lastskip@a\flushend@@lastskip@b
                    \unskip\unpenalty
                    \global\flushend@@lastskip@b\lastskip
                    \global\advance\flushend@@lastskip@c by\lastskip
                \ifdim\flushend@@lastskip@b=-\flushend@@lastskip@a
                    \global\advance\flushend@@lastskip@c by-\lastskip
                \else
                \repeat
                \ifdim\flushend@@lastskip@b=-\flushend@@lastskip@a
                    \ifdim\flushend@@lastskip@b=\z@
                        \setbox\flushend@@varbox@a\lastbox
                        \global\advance\flushend@@lastskip@c by\ht\flushend@@varbox@a
                        \global\advance\flushend@@lastskip@c by\lastskip
                        \unskip\unpenalty
                        \setbox\flushend@@varbox@a\lastbox
                        \global\advance\flushend@@lastskip@c by\dp\flushend@@varbox@a
                    \else
                        \global\flushend@@lastskip@c\lastskip
                        \global\advance\flushend@@lastskip@c by\topskip
                    \fi
                \fi
                \global\advance\flushend@@lastskip@c by-\topskip
                }%
            \setbox\@tempboxa\vbox{%
                \unvbox\@leftcolumn
                \unskip\unpenalty
                \vskip\flushend@@lastskip@c
                \hrule\@height\flushend@@page@rule width\columnwidth
                \the\atColsBreak
                \unvbox\@outputbox
                \remove@lastbox@at@balancing
                \the\atColsEnd
            }%
        \else
            \setbox\@tempboxa\vbox{%
                \unvbox\@leftcolumn
                \setbox\z@\lastbox
                \unskip
                \hrule\@height\flushend@@page@rule width\columnwidth
                \the\atColsBreak
                \unvbox\@outputbox
                \remove@lastbox@at@balancing
                \the\atColsEnd
                }%
        \fi
        \@tempdimb .5\ht\@tempboxa
        \loop
            \setbox\flushend@@tempbox@a\copy\@tempboxa
            \setbox\flushend@@tempbox@c\vbox to\@tempdimb{%
                \vsplit\flushend@@tempbox@a to\@tempdimb
                \vss
                \vsplit\flushend@@tempbox@a to\@tempdimb
                }%
            \wlog{Extra height:\the\ht\flushend@@tempbox@a\space when \the\@tempdimb}%
        \ifvoid\flushend@@tempbox@a
        \else
            \advance\@tempdimb 1\p@
        \repeat
        \loop
            \setbox\flushend@@tempbox@a\copy\@tempboxa
            \setbox\flushend@@tempbox@c\vbox to\@tempdimb{%
                \vsplit\flushend@@tempbox@a to\@tempdimb
                \vss
                }%
            \wlog{(2)Left:\the\ht\flushend@@tempbox@c\space
                    Right:\the\ht\flushend@@tempbox@a\space
                   Output:\the\@tempdimb
                 }%
        \ifdim\ht\flushend@@tempbox@c<\ht\flushend@@tempbox@a
            \@tempdimb=\the\ht\flushend@@tempbox@a
        \repeat
        \wlog{- LAST -^^JExtra skip: \the\z@
                      ^^JLeft:\the\ht\flushend@@tempbox@c
                      ^^JRight:\the\ht\flushend@@tempbox@a
                      ^^JOutput:\the\@tempdimb
             }%
        \setbox\flushend@@tempbox@c\vbox to\@tempdimb{%
            \vsplit\@tempboxa to\@tempdimb
            \vss
            }%
        \setbox\@leftcolumn\vbox to\@tempdima{%
            \fmt@vbox@adds[\columnwidth]{%
                \vbox to\@tempdimb{%
                    \unvbox
                    \flushend@@tempbox@c
                    }%
                }%
            \hrule\@height\flushend@@page@rule
            \vss
            }%
        \setbox\@outputbox\vbox to\@tempdima{%
            \fmt@vbox@adds[\columnwidth]{%
                \vbox to\@tempdimb{%
                    \unvbox\@tempboxa
                    \vskip\z@
                    }%
                }%
            \hrule\@height\flushend@@page@rule
            \vss
            }%
        \setbox\@outputbox\vbox{%
            \hb@xt@\textwidth{%
                \hb@xt@\columnwidth{\box\@leftcolumn\hss}%
                \hfil
                \vrule \@width\columnseprule
                \hfil
                \hb@xt@\columnwidth{\box\@outputbox\hss}%
                }%
            }%
        \global\let\@outputdblcol\saved@orig@@outputdblcol
        \global\atColsEnd{}%
        \ifvoid\hold@viper
        \else
            \setbox\@outputbox\vbox{\box\hold@viper\box\@outputbox}%
        \fi
        \@combinedblfloats
        \@outputpage
        \begingroup
            \@dblfloatplacement
            \@startdblcolumn
            \@whilesw\if@fcolmade\fi
                {\@outputpage\@startdblcolumn}%
            \ifvoid\@viper
            \else
                \global\setbox\@viper\vbox{%
                    \vskip-\stripsep
                    \unvbox\@viper
                    }%
                \csname @viperoutput\endcsname
            \fi
        \endgroup
    \fi
    }
\usepackage{etoolbox}
\AtBeginDocument{%
    \global\let\saved@orig@@outputdblcol\@outputdblcol
    \if@ancient@balance@version
        \global\let\last@outputdblcol\last@outputdblcol@ancient
    \else
        \global\let\last@outputdblcol\last@outputdblcol@modern
    \fi
    \global\let\balanced@@outputdblcol\last@outputdblcol
    \preto\enddocument{\let\@outputdblcol\balanced@@outputdblcol}%
    \appto\footnoterule{\vskip\z@}%
    }
\def\flushcolsend{\global\let\@outputdblcol\last@outputdblcol}
\def\raggedcolsend{\global\let\@outputdblcol\saved@orig@@outputdblcol}
\def\flushend{\global\let\balanced@@outputdblcol\last@outputdblcol}
\def\raggedend{\global\let\balanced@@outputdblcol\saved@orig@@outputdblcol}
\if@balance@debug
    \showcolsendrule
\fi
\endinput
%%
%% End of file `flushend.sty'.
