[Tex/LaTex] autogobble for lstinputlistings

indentationlistings

In the manual for listings it says that gobble has no effect for lstinputlistings. Since the manual is about four years old now and after reading How to automatically skip leading white spaces in listings my question is if there is a way to activate gobble or even better autogobble for lstinputlistings?

Edit: I have tried \lstinputlistings[gobble=3]{hello.c} and it does not work and I have set tabsize=3.

MWE:

\documentclass{article}

\usepackage{listings}
\lstset{tabsize=3,frame=single,numbers=left}

\usepackage{filecontents}
\begin{filecontents*}{hello.c}
if (a<b){
    if (b<a){
        //do something
    }
}
\end{filecontents*}

\begin{document}
\noindent
Using \verb|\begin{lstlisting}... gobble=3| works:
\begin{lstlisting}[gobble=3,firstnumber=2,linerange={2-4}]
if (a<b){
    if (b<a){
        //do something
    }
}
\end{lstlisting}

\bigskip\noindent
Using \verb|\lstinputlisting gobble| does not work:
\lstinputlisting[gobble=3,firstnumber=2,linerange={2-4}]{hello.c}
\end{document}

enter image description here

Update: after playing around with S. Murugan's code I came up with this which also sets firstnumber according to firstline — something I've also wanted.

\documentclass{article}
\usepackage{listings,xifthen,filecontents}

\lstset{tabsize=3,numbers=left,frame=single,basicstyle=\Huge\ttfamily,columns=flexible}
\newlength{\gobble}
\newlength{\gobblea}
% The width of a single space. basicstyle from lstset should be used
\sbox0{\Huge\ttfamily \ }
\newcommand{\mylist}[5]{
%#1 is number of tabs, could be calculated like in listings-autogobble with autogobble=true or be an extra option
%#2 is tabsize, which is set in lstset
%#3 is firstline from lstset
%#4 is lastline from lstset
%#5 is the filename, the only thing which should be an argument and not an option.

% Remove a single space
\setlength{\gobble}{-\the\wd0}
% Reindent a bit by dividing by 1.1, then multiply by tabsize and number of indentation levels
\setlength{\gobble}{0.90909090909090909090909090909091\gobble*#1*#2}
\setlength{\gobblea}{\gobble}
\addtolength{\gobblea}{10pt}
% Check if firstline is defined
\ifthenelse{\isempty{#3} \OR \equal{#3}{0}}{%
% Check if lastline is defined
\ifthenelse{\isempty{#4}}{%
\lstinputlisting[firstnumber=1,firstline=1,framexleftmargin=\gobble,xleftmargin=\gobble,numbersep=\gobblea]{#5}
}{
\lstinputlisting[firstnumber=1,firstline=1,lastline=#4,framexleftmargin=\gobble,xleftmargin=\gobble,numbersep=\gobblea]{#5}
}
}{
\ifthenelse{\isempty{#4}}{%
\lstinputlisting[firstnumber=#3,firstline=#3,framexleftmargin=\gobble,xleftmargin=\gobble,numbersep=\gobblea]{#5}
}{
\lstinputlisting[firstnumber=#3,firstline=#3,lastline=#4,framexleftmargin=\gobble,xleftmargin=\gobble,numbersep=\gobblea]{#5}
}
}
}

\begin{filecontents*}{hello.c}
if (b<a){
   //do something
}
\end{filecontents*}
\begin{filecontents*}{hello1.c}
if (a<b){
   if (b<a){
      //do something
   }
}
\end{filecontents*}

\begin{document}
\lstinputlisting[firstnumber=2,linerange={1-3}]{hello.c}
%mylist{#tabs}{#tabsize}{firstline}{lastline}{filename}
\mylist{1}{3}{2}{4}{hello1.c}
\mylist{2}{3}{3}{3}{hello1.c}
\end{document}

Update Now it should work for any font size (tested from 8 to 60pt) and for any basicstyle (tested from \tiny to \Huge).
Now it would be really nice, if I could just write \lstinputlisting[tabs=1,firstline=2,lastline=4]{hello.c} and it would fetch tabsize=3 and basicstyle=\Huge\ttfamily from lstset{}.

Update 7/06/2013
In How to extend the \lstinputlisting command there is a nicer way to achieve the desired result.

Best Answer

Now check this:

\documentclass{article}

\usepackage{listings}
\lstset{tabsize=3,frame=single,numbers=left}

\usepackage{filecontents}
\begin{filecontents*}{hello.c}
if (a<b){
    if (b<a){
        //do something
    }
}
\end{filecontents*}

\begin{document}
\noindent Using \verb|\begin{lstlisting}... gobble=3| works:
\begin{lstlisting}[gobble=3,firstnumber=2,linerange={2-4}]
if (a<b){
    if (b<a){
        //do something
    }
}
\end{lstlisting}

\bigskip\noindent
Using \verb|\lstinputlisting gobble| does not work:

\lstinputlisting[tabsize=2,showspaces=false,gobble=3,firstnumber=2,linerange={2-4},framexleftmargin=-16pt,numbersep=-8pt,xleftmargin=-18pt]{hello.c}

\end{document}
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