
%%%%%%%%%%%% The macro \EAN generates EAN-8 barcodes. %%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% May 30, 1995                             Jaroslav Moucka (Mou\v{c}ka)

% This macro is inspired by ean13 macro by Petr Olsak
% The ean8 macro is very similar as ean13 and more simple.  
% Don't change the Copyright message.
% You can use the macro on your own risk.
% The macro must be tested! There is no warranty that the macro works OK.

% Usage: For example \EAN 8591-2342 generates the \vbox with barcodes
% in TeX hight accuracy using \rule primitive.
% The EAN number is appended downwards in OCR-b font (9pt).
% Don't use brackets in parameters!
% The macro checks the checksum in EAN.

% Recomendation: If you plan the offset print, use the barcode
% correction 20 for your phototypesetter. See the \bcorr=.020mm bellow.

\font\ocrb=ocrb9

\newcount\numlines \newcount\nummodules
\newcount\numdigit \newcount\evensum \newcount\oddsum

\newdimen\X  \newdimen\bcorr  \newdimen\workdimen  \newdimen\barheight   

%%% First, we prepare internal code in format: dig dig dig (44 digits).
%%% Odd possition of dig is number of moduls for white space,
%%% even for black space; from left to right.

\def\internalcode{0111}             % Begin mark at start
\def\frontdigits{}                  % 8--5 digit of EAN

%%% EAN-8:
\message{The EAN-8 barcodes macro. Copyright (C) Jaroslav Moucka, 1995}

\def\EAN{\begingroup\EANscan}

\def\EANscan#1{\if#1-\let\next=\EANscan \else
    \advance\numdigit by1
    \ifnum\numdigit<8
      \ifodd\numdigit \advance\evensum by #1 \else \advance\oddsum by #1 \fi
      \let\next=\EANscan
      \ifnum\numdigit=1 \def\tabs{\A\A\A\A} \fi
      \ifnum\numdigit<5 \usetabA #1 \edef\frontdigits{\frontdigits#1} \else
      \ifnum\numdigit=5 \insertseparator \A \usetabC #1 \def\enddigits{#1}
      \else             \usetabC #1 \edef\enddigits{\enddigits#1}
      \fi\fi
    \else \testchecksum #1 \usetabC #1 \edef\enddigits{\enddigits#1}
      \let\next=\EANclose
    \fi\fi \next}


\def\EANclose{\insertendmark
    \wlog{EAN: \frontdigits\space\enddigits}
    \wlog{EANinternal: \internalcode}
    \expandafter\EANbox\internalcode..\endgroup}

\def\testchecksum#1{\multiply\evensum by3 \advance\evensum by\oddsum
    \oddsum=\evensum
    \divide\oddsum by10 \multiply\oddsum by10 \advance\oddsum by10
    \advance\oddsum by-\evensum \ifnum\oddsum=10 \oddsum=0 \fi
    \ifnum#1=\oddsum \else
    \errmessage{The checksum digit has to be \the\oddsum, no #1 !}\fi}

\def\A{\def\0{3211}\def\1{2221}\def\2{2122}\def\3{1411}\def\4{1132}
  \def\5{1231}\def\6{1114}\def\7{1312}\def\8{1213}\def\9{3112}}

\def\usetabA#1{\expandafter\scantab\tabs\end \usetabC #1}

\def\scantab#1#2\end{#1\def\tabs{#2}}

\def\usetabC#1{\edef\internalcode{\internalcode\csname#1\endcsname}}

\def\insertseparator{\edef\internalcode{\internalcode 11111}}

\def\insertendmark{\edef\internalcode{\internalcode 111}}


\def\EANbox{\vbox\bgroup\offinterlineskip
  \setbox0=\hbox\bgroup \kern7\X \EANrepeat}

\def\EANrepeat#1#2{\if#1.\let\next=\EANfinal \else\let\next=\EANrepeat
  \advance\numlines by1
  \advance\nummodules by#1 \advance\nummodules by#2
  \workdimen=#1\X \advance\workdimen by \bcorr \kern\workdimen
     \workdimen=#2\X \advance\workdimen by-\bcorr \vrule width\workdimen
     \ifdim\barheight=0pt height 55.24242424\X \else height\barheight \fi     
     \ifnum\numlines=1  depth5\X\else
     \ifnum\numlines=2  depth5\X\else
     \ifnum\numlines=11 depth5\X\else
     \ifnum\numlines=12 depth5\X\else
     \ifnum\numlines=21 depth5\X\else
     \ifnum\numlines=22 depth5\X\else depth0pt \fi\fi\fi\fi\fi\fi
  \fi\next}

\def\EANfinal{\testconsistence
  \kern7\X\egroup
  \dp0=0pt \box0 \kern-1\X
  \hbox{\ocrb\kern11\X \frontdigits\kern5\X \enddigits}
  \egroup }

\def\internalerr{\errmassage{Sorry, my internal tables are wrong, may be.}}

\def\testconsistence{\ifnum\numlines=22\else\internalerr\fi
  \ifnum\nummodules=67\else\internalerr\fi}

\barheight=0pt
\X=.33mm       % Basic size 100%, SC2 code
\bcorr=.020mm  % Barcode correction for offset 
\endinput


