LaTeX: To get the current page number

bxcurpage.sty

%% bxcurpage.sty

%% package declaration
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{bxcurpage}[2016/12/01 v0.2]
\def\bxpg@pkgname{bxcurpage}

%--------------------------------------- helpers

%% packages
\RequirePackage{zref}

%% LaTeX counters
\newcounter{bxpg@id}
\newcounter{currentpage}
\def\thecurrentpage{??}

%% variables
\let\bxpg@label@name\relax

%--------------------------------------- main

%% zref settings
\zref@newprop*{bxpg@pageval}[0]{\number\c@page}%
\zref@addprop{main}{bxpg@pageval}

%%<*> \getcurrentpage
\@ifdefinable{\getcurrentpage}{%
  \DeclareRobustCommand*\getcurrentpage{%
    \refstepcounter{bxpg@id}%
    \edef\bxpg@label@name{bxpg:\the\c@bxpg@id}%
    \edef\bxpg@next{%
      \noexpand\zref@label{\bxpg@label@name}%
    }\bxpg@next
    \zref@refused\bxpg@label@name
    \zref@ifrefundefined\bxpg@label@name{%
      \global\c@currentpage=\c@page
      \global\let\thecurrentpage\thepage
    }{%
      \global\c@currentpage=%
          \zref@extract\bxpg@label@name{bxpg@pageval}\relax
      \zref@def@extract\bxpg@next\bxpg@label@name{page}%
      \global\let\thecurrentpage\bxpg@next
    }%
  }%
}

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