% bxdvidriver.sty

%% package declaration
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{bxdvidriver}[2017/02/13 v0.2a]

%% preparation
\def\bxdd@pkgname{bxdvidriver}
\providecommand\bxDebug[1]{}

%--------------------------------------- general

%% \bxdd@dvi@driver@list
% List of dvi-driver names.
\@onlypreamble\bxdd@dvi@driver@list
\def\bxdd@dvi@driver@list{%
  dvips,xdvi,dvipdf,dvipdfm,dvipdfmx,dvipsone,%
  dviwindo,oztex,textures,pctexps,pctex32}
%% \bxdd@pdf@driver@list
% List of pdf-driver names.
\@onlypreamble\bxdd@pdf@driver@list
\def\bxdd@pdf@driver@list{%
  pdftex,xetex,luatex,vtex}

%% packages
\RequirePackage{ifpdf,ifxetex,ifluatex,ifvtex}
\RequirePackage{pdftexcmds}

%% variables
\newif\ifbxdd@ok
\@onlypreamble\bxdd@driver
\let\bxdd@driver\relax  % driver given to this package
\@onlypreamble\bxdd@pdf@driver
\let\bxdd@pdf@driver\relax  % actual pdf-mode driver, or \relax

%% \[bxdd@T/<driver>]
\@for\bxdd@x:=\bxdd@dvi@driver@list\do{%
  \expandafter\let\csname bxdd@T/\bxdd@x\endcsname=d}
\@for\bxdd@x:=\bxdd@pdf@driver@list\do{%
  \expandafter\let\csname bxdd@T/\bxdd@x\endcsname=p}

%% \bxdd@detokenize\CS
\def\bxdd@detokenize#1{%
  \expandafter\bxdd@detokenize@a\meaning#1\relax#1}
\def\bxdd@detokenize@a#1>#2\relax#3{%
  \def#3{#2}}

%% switch 'bxdd@in@preamble'
\newif\ifbxdd@in@preamble
\ifx\documentclass\@twoclasseserror
  \bxdd@in@preambletrue
\fi

%--------------------------------------- options

%% 'check'/'nocheck'
\newif\ifbxdd@check \bxdd@checktrue
\DeclareOption{check}{%
  \bxdd@checktrue}
\DeclareOption{nocheck}{%
  \bxdd@checkfalse}
%% driver options
\DeclareOption*{%
  \bxdd@pfxplus\CurrentOption \ifx\bxdd@tmpa\@empty
    \let\bxdd@tmpa\CurrentOption
  \else
    \expandafter\let\csname bxdd@T/\bxdd@tmpa\endcsname=d%
  \fi
  \expandafter\let\expandafter\bxdd@tmpb
      \csname bxdd@T/\bxdd@tmpa\endcsname
  \ifx\bxdd@tmpb\relax % unknown name
    \PackageError\bxdd@pkgname
     {Unknown driver name '\bxdd@tmpa' found}%
     {The invalid option is ignored.\MessageBreak\@ehc}
  \else\ifx\bxdd@driver\relax % first
    \let\bxdd@driver\bxdd@tmpa
  \else\ifx\bxdd@driver\bxdd@tmpa % repeated
    \PackageInfo\bxdd@pkgname
     {Redundant driver option '\bxdd@tmpa',\MessageBreak
      found}%
  \else % second
    \PackageError\bxdd@pkgname
     {Multiple driver options are given\MessageBreak
      ('\bxdd@driver' and '\bxdd@tmpa')}%
      {The extra option '\bxdd@tmpa' is ignored.\MessageBreak\@ehc}
  \fi\fi\fi}
\def\bxdd@pfxplus#1{%
  \expandafter\bxdd@pfxplus@a#1\@gobble+\@nil}
\def\bxdd@pfxplus@a#1+#2\@nil{%
  \edef\bxdd@tmpa{\ifx\@nil#1\@nil#2\else\fi}}
%%
\ProcessOptions*

%% check consistency
\ifx\bxdd@driver\relax
  \PackageInfo\bxdd@pkgname
   {No driver option given,}
\else\expandafter\ifx\csname bxdd@T/\bxdd@driver\endcsname p%
  \PackageWarning\bxdd@pkgname
   {The driver '\bxdd@driver' is a pdf-mode driver and\MessageBreak
    inappropriate for this package,}
\else\bxDebug{driver=\bxdd@driver}
\fi\fi

%--------------------------------------- pdf-mode detection

%% check 'pdfmode' and set \bxdd@pdf@driver
\bxdd@oktrue
\ifluatex
  \let\bxdd@tmpa\m@ne
  \pdf@isprimitive\outputmode\outputmode{\let\bxdd@tmpa\outputmode}{}
  \pdf@isprimitive\pdfoutput\pdfoutput{\let\bxdd@tmpa\pdfoutput}{}
  \ifnum\bxdd@tmpa>\z@
    \def\bxdd@pdf@driver{luatex}%
  \else\ifnum\bxdd@tmpa<\z@
    \PackageError\bxdd@pkgname
     {INTERNAL ERROR (1)}
     {Package loading is aborted.\MessageBreak\@ehc}
    \bxdd@okfalse
  \fi\fi
\else\ifxetex
  \def\bxdd@pdf@driver{xetex}
\else\ifvtex
  \def\bxdd@pdf@driver{vtex}
\else\ifpdf
  \def\bxdd@pdf@driver{pdftex}
\fi\fi\fi\fi
\ifbxdd@ok\else
\expandafter\endinput\fi\relax

% clear \bxdd@driver if pdf-mode
\ifx\bxdd@pdf@driver\relax\else
  \PackageInfo\bxdd@pkgname
   {Driver option '\bxdd@driver' is ignored, because\MessageBreak
    the engine is in pdf-mode,}
  \let\bxdd@driver\relax
\fi

%--------------------------------------- append to global

%% variables
\let\bxdd@gopt\relax
\let\bxdd@godrv\relax
\let\bxdd@godrv@multiple=M% flag value

%% \bxdd@scan@global@options
\@onlypreamble\bxdd@scan@global@options
\def\bxdd@scan@global@options{%
  \begingroup
  \@for\bxdd@gopt:=\@classoptionslist\do{%
    \let\bxdd@tmpa\bxdd@gopt \bxdd@detokenize\bxdd@tmpa
    \expandafter\ifx\csname bxdd@T/\bxdd@tmpa\endcsname\relax\else
      \ifbxdd@in@preamble
        \@expandtwoargs\@removeelement\bxdd@gopt
            \@unusedoptionlist\@unusedoptionlist
      \fi
      \ifx\bxdd@godrv\bxdd@gopt % just redundant
      \else\ifx\bxdd@godrv\relax % first
        \let\bxdd@godrv\bxdd@gopt
      \else\ifx\bxdd@godrv\bxdd@godrv@multiple % more
        \PackageInfo\bxdd@pkgname
         {Extra driver option in global option list\MessageBreak
          ('\bxdd@gopt'),}%
      \else % second
        \PackageInfo\bxdd@pkgname
         {Multiple driver options in global option list\MessageBreak
          ('\bxdd@godrv' and '\bxdd@gopt'),}%
        \let\bxdd@godrv\bxdd@godrv@multiple
      \fi\fi\fi
    \fi}
  \global\let\@unusedoptionlist\@unusedoptionlist
  \aftergroup\bxdd@okfalse
  \ifx\bxdd@godrv\relax
    \ifx\bxdd@driver\relax\else
      \PackageInfo\bxdd@pkgname
       {Driver option '\bxdd@driver' is appended to the\MessageBreak
        global option list,}
      \aftergroup\bxdd@oktrue
    \fi
  \else\ifx\bxdd@godrv\bxdd@driver
    \PackageInfo\bxdd@pkgname
     {Driver option '\bxdd@driver' is already contained\MessageBreak
      in the global option list,}
  \else\ifx\bxdd@godrv\bxdd@godrv@multiple
    \ifbxdd@check
      \PackageError\bxdd@pkgname
       {Multiple driver options in global option list\MessageBreak
        (see log for detail)}%
       {\@ehd}%
    \fi
  \else\ifx\bxdd@driver\relax
    % nothing to do
  \else % inconsistent
    \ifbxdd@check
      \PackageError\bxdd@pkgname
       {The driver specified is '\bxdd@driver',\MessageBreak
        but the global list contains '\bxdd@godrv'}%
       {\@ehd}%
    \else
      \PackageInfo\bxdd@pkgname
       {Driver option '\bxdd@driver' is discarded,\MessageBreak
        because the global option list contains another driver\MessageBreak
        '\bxdd@godrv',}
    \fi
  \fi\fi\fi\fi
  \endgroup}

%% append the specified driver option
\ifbxdd@in@preamble
  \bxdd@scan@global@options
  \ifbxdd@ok
    \edef\bxdd@tmpa{%
      \noexpand\g@addto@macro\noexpand\@classoptionslist{%
        ,\bxdd@driver}%
    }\bxdd@tmpa
  \fi
\else % 'before-preamble'
  \let\bxdd@org@fileswith@pti@ns\@fileswith@pti@ns
  \def\@fileswith@pti@ns#1{%
    \ifx#1\@clsextension
      \let\@fileswith@pti@ns\bxdd@org@fileswith@pti@ns
      \let\bxdd@org@fileswith@pti@ns\@undefined
      \g@addto@macro\@documentclasshook{%
        \bxdd@scan@global@options}%
      \ifx\bxdd@driver\relax
        \def\bxdd@tmpa{\@fileswith@pti@ns#1}%
      \else
        \edef\bxdd@tmpa{\noexpand\bxdd@tmpb{\bxdd@driver}}%
        \def\bxdd@tmpb##1[##2]{\@fileswith@pti@ns#1[{##2,##1}]}%
      \fi
    \else
      \def\bxdd@tmpa{\bxdd@org@fileswith@pti@ns#1}%
    \fi
    \bxdd@tmpa}
\fi

%--------------------------------------- check for graphics drivers

%% \bxdd@scan@graphics@drivers
\@onlypreamble\bxdd@scan@graphics@drivers
\def\bxdd@scan@graphics@drivers{%
  \begingroup
  \edef\bxdd@tmpa{\bxdd@dvi@driver@list,\bxdd@pdf@driver@list}%
  \@for\bxdd@gopt:=\bxdd@tmpa\do{%
    \expandafter\ifx\csname ver@\bxdd@gopt.def\endcsname\relax\else
      \ifx\bxdd@godrv\relax % first
        \let\bxdd@godrv\bxdd@gopt
      \else\ifx\bxdd@godrv\bxdd@godrv@multiple % more
        \PackageInfo\bxdd@pkgname
         {Extra graphics driver is loaded\MessageBreak
          ('\bxdd@gopt'),}%
      \else % second
        \PackageInfo\bxdd@pkgname
         {Multiple graphics driver is loaded\MessageBreak
          ('\bxdd@godrv' and '\bxdd@gopt'),}%
        \let\bxdd@godrv\bxdd@godrv@multiple
      \fi\fi
    \fi}
  \ifx\bxdd@godrv\relax
    \PackageInfo\bxdd@pkgname
     {No graphics driver used,}
  \else\ifx\bxdd@godrv\bxdd@godrv@multiple
    \ifbxdd@check
      \PackageError\bxdd@pkgname
       {Multiple graphics drivers are loaded\MessageBreak
        (see log for detail)}%
       {\@ehd}%
    \fi
  \else
    \PackageInfo\bxdd@pkgname
     {Graphics driver is '\bxdd@godrv',}
  \fi\fi
  \endgroup}

%% add hook
\AtBeginDocument{%
  \bxdd@scan@graphics@drivers}

%--------------------------------------- all done
\endinput
%% EOF