%% Copyright (c) 2011-2022 by Martin Scharrer <martin.scharrer@web.de>
%% -----------------------------------------------------------------------
%% 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.
%%
%% This work has the LPPL maintenance status `maintained'.
%%
%% The Current Maintainer of this work is Martin Scharrer.
%%
%% This work consists of the files lstautogobble.dtx and lstaddons.ins
%% and the derived filebase lstautogobble.sty.
%%
\ProvidesPackage{lstautogobble}[%
    2012/05/03
    v0.1
    Implements 'autogobble' option for 'listings']

\RequirePackage{listings}

\newcount\lstag@spacecount

\def\lstag@activespace{\lst@ProcessSpace}%  Definition of an active space
\def\lstag@tabulator{\lst@ProcessTabulator}%  Definition of an tabulator

\begingroup
\catcode`\^^M=\active%
\gdef\lstag@activenl{^^M}%  Active CR (ASCII 13) character which is used as line break
\endgroup

\lst@Key{autogobble}{false}[t]{\lstKV@SetIf{#1}\lst@ifautogobble}

\lst@Key{ungobble}{0}{\def\lst@ungobble{#1}}

\lst@AddToHook{Init}{\lst@autogobble}

\def\lst@autogobble{%
    \lst@ifautogobble
        \ifnum\lst@gobble>0\else
            \def\lst@gobble{\lstag@gobble}%
            \def\lstag@gobble{0}%
            \lstag@spacecount\z@
            \def\lstag@spaceaccu{}%
            \let\lstag@restofline\empty
            \let\lstag@origlstenv@Process\lstenv@Process
            \let\lstenv@Process\lstag@countleadingspaces
        \fi
    \fi
}

\def\lstag@countleadingspaces#1{%
    \expandafter\ifx\lstag@activenl#1\relax
        \expandafter\lstag@countleadingspaces@
    \else
        \def\lstag@restofline{Dummy replacement of text after begin of listing to trigger original warning message}%
        \expandafter\lstag@countleadingspaces
    \fi
}

\def\lstag@countleadingspaces@#1{%
    \ifx\lstag@activespace#1\relax
        \advance\lstag@spacecount by \@ne
        % Accumulate spaces (i.e. their definitions) for later re-insertion:
        \expandafter\def\expandafter\lstag@spaceaccu\expandafter{\lstag@spaceaccu\lst@ProcessSpace}%
        \let\next\lstag@countleadingspaces@
    \else% Character wasn't a space
    \ifx\lstag@tabulator#1\relax
        \advance\lstag@spacecount by \lst@tabsize\relax
        % Accumulate spaces (i.e. their definitions) for later re-insertion:
        \@tempcnta=\lst@tabsize\relax
        \loop
        \ifnum\@tempcnta>\z@
            \expandafter\def\expandafter\lstag@spaceaccu\expandafter{\lstag@spaceaccu\lst@ProcessSpace}%
            \advance\@tempcnta\m@ne
        \repeat
        \let\next\lstag@countleadingspaces@
    \else% Character wasn't a tabulator either
        % Set gobble option (indirect):
        \xdef\lstag@gobble{\the\numexpr\lstag@spacecount-\lst@ungobble\relax}%
        % Restore original definition of process macro:
        \global\let\lstenv@Process\lstag@origlstenv@Process
        % Re-insert all collected material or appropriate replacement material:
        \edef\next{\noexpand\lstenv@Process\lstag@restofline\expandafter\noexpand\lstag@activenl\expandafter\unexpanded\expandafter{\lstag@spaceaccu}\noexpand#1}%
    \fi\fi
    \next
}
\endinput
%%
%% End of file `lstautogobble.sty'.
