################################################################################
##
##  Version 3.x, Copyright (C) 2004-2013, Marcus Holland-Moritz.
##  Version 2.x, Copyright (C) 2001, Paul Marquess.
##  Version 1.x, Copyright (C) 1999, Kenneth Albanowski.
##
##  This program is free software; you can redistribute it and/or
##  modify it under the same terms as Perl itself.
##
################################################################################

=provides

=implementation

use strict;

# Disable broken TRIE-optimization
BEGIN { eval '${^RE_TRIE_MAXBUF} = -1' if $] >= 5.009004 && $] <= 5.009005 }

my $VERSION = __VERSION__;

my %opt = (
  quiet     => 0,
  diag      => 1,
  hints     => 1,
  changes   => 1,
  cplusplus => 0,
  filter    => 1,
  strip     => 0,
  version   => 0,
);

my($ppport) = $0 =~ /([\w.]+)$/;
my $LF = '(?:\r\n|[\r\n])';   # line feed
my $HS = "[ \t]";             # horizontal whitespace

# Never use C comments in this file!
my $ccs  = '/'.'*';
my $cce  = '*'.'/';
my $rccs = quotemeta $ccs;
my $rcce = quotemeta $cce;

eval {
  require Getopt::Long;
  Getopt::Long::GetOptions(\%opt, qw(
    help quiet diag! filter! hints! changes! cplusplus strip version
    patch=s copy=s diff=s compat-version=s
    list-provided list-unsupported api-info=s
  )) or usage();
};

if ($@ and grep /^-/, @ARGV) {
  usage() if "@ARGV" =~ /^--?h(?:elp)?$/;
  die "Getopt::Long not found. Please don't use any options.\n";
}

if ($opt{version}) {
  print "This is $0 $VERSION.\n";
  exit 0;
}

usage() if $opt{help};
strip() if $opt{strip};

if (exists $opt{'compat-version'}) {
  my($r,$v,$s) = eval { parse_version($opt{'compat-version'}) };
  if ($@) {
    die "Invalid version number format: '$opt{'compat-version'}'\n";
  }
  die "Only Perl 5 is supported\n" if $r != 5;
  die "Invalid version number: $opt{'compat-version'}\n" if $v >= 1000 || $s >= 1000;
  $opt{'compat-version'} = sprintf "%d.%03d%03d", $r, $v, $s;
}
else {
  $opt{'compat-version'} = 5;
}

my %API = map { /^(\w+)\|([^|]*)\|([^|]*)\|(\w*)$/
                ? ( $1 => {
                      ($2                  ? ( base     => $2 ) : ()),
                      ($3                  ? ( todo     => $3 ) : ()),
                      (index($4, 'v') >= 0 ? ( varargs  => 1  ) : ()),
                      (index($4, 'p') >= 0 ? ( provided => 1  ) : ()),
                      (index($4, 'n') >= 0 ? ( nothxarg => 1  ) : ()),
                    } )
                : die "invalid spec: $_" } qw(
__PERL_API__
);

if (exists $opt{'list-unsupported'}) {
  my $f;
  for $f (sort { lc $a cmp lc $b } keys %API) {
    next unless $API{$f}{todo};
    print "$f ", '.'x(40-length($f)), " ", format_version($API{$f}{todo}), "\n";
  }
  exit 0;
}

# Scan for possible replacement candidates

my(%replace, %need, %hints, %warnings, %depends);
my $replace = 0;
my($hint, $define, $function);

sub find_api
{
  my $code = shift;
  $code =~ s{
    / (?: \*[^*]*\*+(?:[^$ccs][^*]*\*+)* / | /[^\r\n]*)
  | "[^"\\]*(?:\\.[^"\\]*)*"
  | '[^'\\]*(?:\\.[^'\\]*)*' }{}egsx;
  grep { exists $API{$_} } $code =~ /(\w+)/mg;
}

while (<DATA>) {
  if ($hint) {
    my $h = $hint->[0] eq 'Hint' ? \%hints : \%warnings;
    if (m{^\s*\*\s(.*?)\s*$}) {
      for (@{$hint->[1]}) {
        $h->{$_} ||= '';  # suppress warning with older perls
        $h->{$_} .= "$1\n";
      }
    }
    else { undef $hint }
  }

  $hint = [$1, [split /,?\s+/, $2]]
      if m{^\s*$rccs\s+(Hint|Warning):\s+(\w+(?:,?\s+\w+)*)\s*$};

  if ($define) {
    if ($define->[1] =~ /\\$/) {
      $define->[1] .= $_;
    }
    else {
      if (exists $API{$define->[0]} && $define->[1] !~ /^DPPP_\(/) {
        my @n = find_api($define->[1]);
        push @{$depends{$define->[0]}}, @n if @n
      }
      undef $define;
    }
  }

  $define = [$1, $2] if m{^\s*#\s*define\s+(\w+)(?:\([^)]*\))?\s+(.*)};

  if ($function) {
    if (/^}/) {
      if (exists $API{$function->[0]}) {
        my @n = find_api($function->[1]);
        push @{$depends{$function->[0]}}, @n if @n
      }
      undef $function;
    }
    else {
      $function->[1] .= $_;
    }
  }

  $function = [$1, ''] if m{^DPPP_\(my_(\w+)\)};

  $replace     = $1 if m{^\s*$rccs\s+Replace:\s+(\d+)\s+$rcce\s*$};
  $replace{$2} = $1 if $replace and m{^\s*#\s*define\s+(\w+)(?:\([^)]*\))?\s+(\w+)};
  $replace{$2} = $1 if m{^\s*#\s*define\s+(\w+)(?:\([^)]*\))?\s+(\w+).*$rccs\s+Replace\s+$rcce};
  $replace{$1} = $2 if m{^\s*$rccs\s+Replace (\w+) with (\w+)\s+$rcce\s*$};

  if (m{^\s*$rccs\s+(\w+(\s*,\s*\w+)*)\s+depends\s+on\s+(\w+(\s*,\s*\w+)*)\s+$rcce\s*$}) {
    my @deps = map { s/\s+//g; $_ } split /,/, $3;
    my $d;
    for $d (map { s/\s+//g; $_ } split /,/, $1) {
      push @{$depends{$d}}, @deps;
    }
  }

  $need{$1} = 1 if m{^#if\s+defined\(NEED_(\w+)(?:_GLOBAL)?\)};
}

for (values %depends) {
  my %s;
  $_ = [sort grep !$s{$_}++, @$_];
}

if (exists $opt{'api-info'}) {
  my $f;
  my $count = 0;
  my $match = $opt{'api-info'} =~ m!^/(.*)/$! ? $1 : "^\Q$opt{'api-info'}\E\$";
  for $f (sort { lc $a cmp lc $b } keys %API) {
    next unless $f =~ /$match/;
    print "\n=== $f ===\n\n";
    my $info = 0;
    if ($API{$f}{base} || $API{$f}{todo}) {
      my $base = format_version($API{$f}{base} || $API{$f}{todo});
      print "Supported at least starting from perl-$base.\n";
      $info++;
    }
    if ($API{$f}{provided}) {
      my $todo = $API{$f}{todo} ? format_version($API{$f}{todo}) : "__MIN_PERL__";
      print "Support by $ppport provided back to perl-$todo.\n";
      print "Support needs to be explicitly requested by NEED_$f.\n" if exists $need{$f};
      print "Depends on: ", join(', ', @{$depends{$f}}), ".\n" if exists $depends{$f};
      print "\n$hints{$f}" if exists $hints{$f};
      print "\nWARNING:\n$warnings{$f}" if exists $warnings{$f};
      $info++;
    }
    print "No portability information available.\n" unless $info;
    $count++;
  }
  $count or print "Found no API matching '$opt{'api-info'}'.";
  print "\n";
  exit 0;
}

if (exists $opt{'list-provided'}) {
  my $f;
  for $f (sort { lc $a cmp lc $b } keys %API) {
    next unless $API{$f}{provided};
    my @flags;
    push @flags, 'explicit' if exists $need{$f};
    push @flags, 'depend'   if exists $depends{$f};
    push @flags, 'hint'     if exists $hints{$f};
    push @flags, 'warning'  if exists $warnings{$f};
    my $flags = @flags ? '  ['.join(', ', @flags).']' : '';
    print "$f$flags\n";
  }
  exit 0;
}

my @files;
my @srcext = qw( .xs .c .h .cc .cpp -c.inc -xs.inc );
my $srcext = join '|', map { quotemeta $_ } @srcext;

if (@ARGV) {
  my %seen;
  for (@ARGV) {
    if (-e) {
      if (-f) {
        push @files, $_ unless $seen{$_}++;
      }
      else { warn "'$_' is not a file.\n" }
    }
    else {
      my @new = grep { -f } glob $_
          or warn "'$_' does not exist.\n";
      push @files, grep { !$seen{$_}++ } @new;
    }
  }
}
else {
  eval {
    require File::Find;
    File::Find::find(sub {
      $File::Find::name =~ /($srcext)$/i
          and push @files, $File::Find::name;
    }, '.');
  };
  if ($@) {
    @files = map { glob "*$_" } @srcext;
  }
}

if (!@ARGV || $opt{filter}) {
  my(@in, @out);
  my %xsc = map { /(.*)\.xs$/ ? ("$1.c" => 1, "$1.cc" => 1) : () } @files;
  for (@files) {
    my $out = exists $xsc{$_} || /\b\Q$ppport\E$/i || !/($srcext)$/i;
    push @{ $out ? \@out : \@in }, $_;
  }
  if (@ARGV && @out) {
    warning("Skipping the following files (use --nofilter to avoid this):\n| ", join "\n| ", @out);
  }
  @files = @in;
}

die "No input files given!\n" unless @files;

my(%files, %global, %revreplace);
%revreplace = reverse %replace;
my $filename;
my $patch_opened = 0;

for $filename (@files) {
  unless (open IN, "<$filename") {
    warn "Unable to read from $filename: $!\n";
    next;
  }

  info("Scanning $filename ...");

  my $c = do { local $/; <IN> };
  close IN;

  my %file = (orig => $c, changes => 0);

  # Temporarily remove C/XS comments and strings from the code
  my @ccom;

  $c =~ s{
    ( ^$HS*\#$HS*include\b[^\r\n]+\b(?:\Q$ppport\E|XSUB\.h)\b[^\r\n]*
    | ^$HS*\#$HS*(?:define|elif|if(?:def)?)\b[^\r\n]* )
  | ( ^$HS*\#[^\r\n]*
    | "[^"\\]*(?:\\.[^"\\]*)*"
    | '[^'\\]*(?:\\.[^'\\]*)*'
    | / (?: \*[^*]*\*+(?:[^$ccs][^*]*\*+)* / | /[^\r\n]* ) )
  }{ defined $2 and push @ccom, $2;
     defined $1 ? $1 : "$ccs$#ccom$cce" }mgsex;

  $file{ccom} = \@ccom;
  $file{code} = $c;
  $file{has_inc_ppport} = $c =~ /^$HS*#$HS*include[^\r\n]+\b\Q$ppport\E\b/m;

  my $func;

  for $func (keys %API) {
    my $match = $func;
    $match .= "|$revreplace{$func}" if exists $revreplace{$func};
    if ($c =~ /\b(?:Perl_)?($match)\b/) {
      $file{uses_replace}{$1}++ if exists $revreplace{$func} && $1 eq $revreplace{$func};
      $file{uses_Perl}{$func}++ if $c =~ /\bPerl_$func\b/;
      if (exists $API{$func}{provided}) {
        $file{uses_provided}{$func}++;
        if (!exists $API{$func}{base} || $API{$func}{base} > $opt{'compat-version'}) {
          $file{uses}{$func}++;
          my @deps = rec_depend($func);
          if (@deps) {
            $file{uses_deps}{$func} = \@deps;
            for (@deps) {
              $file{uses}{$_} = 0 unless exists $file{uses}{$_};
            }
          }
          for ($func, @deps) {
            $file{needs}{$_} = 'static' if exists $need{$_};
          }
        }
      }
      if (exists $API{$func}{todo} && $API{$func}{todo} > $opt{'compat-version'}) {
        if ($c =~ /\b$func\b/) {
          $file{uses_todo}{$func}++;
        }
      }
    }
  }

  while ($c =~ /^$HS*#$HS*define$HS+(NEED_(\w+?)(_GLOBAL)?)\b/mg) {
    if (exists $need{$2}) {
      $file{defined $3 ? 'needed_global' : 'needed_static'}{$2}++;
    }
    else { warning("Possibly wrong #define $1 in $filename") }
  }

  for (qw(uses needs uses_todo needed_global needed_static)) {
    for $func (keys %{$file{$_}}) {
      push @{$global{$_}{$func}}, $filename;
    }
  }

  $files{$filename} = \%file;
}

# Globally resolve NEED_'s
my $need;
for $need (keys %{$global{needs}}) {
  if (@{$global{needs}{$need}} > 1) {
    my @targets = @{$global{needs}{$need}};
    my @t = grep $files{$_}{needed_global}{$need}, @targets;
    @targets = @t if @t;
    @t = grep /\.xs$/i, @targets;
    @targets = @t if @t;
    my $target = shift @targets;
    $files{$target}{needs}{$need} = 'global';
    for (@{$global{needs}{$need}}) {
      $files{$_}{needs}{$need} = 'extern' if $_ ne $target;
    }
  }
}

for $filename (@files) {
  exists $files{$filename} or next;

  info("=== Analyzing $filename ===");

  my %file = %{$files{$filename}};
  my $func;
  my $c = $file{code};
  my $warnings = 0;

  for $func (sort keys %{$file{uses_Perl}}) {
    if ($API{$func}{varargs}) {
      unless ($API{$func}{nothxarg}) {
        my $changes = ($c =~ s{\b(Perl_$func\s*\(\s*)(?!aTHX_?)(\)|[^\s)]*\))}
                              { $1 . ($2 eq ')' ? 'aTHX' : 'aTHX_ ') . $2 }ge);
        if ($changes) {
          warning("Doesn't pass interpreter argument aTHX to Perl_$func");
          $file{changes} += $changes;
        }
      }
    }
    else {
      warning("Uses Perl_$func instead of $func");
      $file{changes} += ($c =~ s{\bPerl_$func(\s*)\((\s*aTHX_?)?\s*}
                                {$func$1(}g);
    }
  }

  for $func (sort keys %{$file{uses_replace}}) {
    warning("Uses $func instead of $replace{$func}");
    $file{changes} += ($c =~ s/\b$func\b/$replace{$func}/g);
  }

  for $func (sort keys %{$file{uses_provided}}) {
    if ($file{uses}{$func}) {
      if (exists $file{uses_deps}{$func}) {
        diag("Uses $func, which depends on ", join(', ', @{$file{uses_deps}{$func}}));
      }
      else {
        diag("Uses $func");
      }
    }
    $warnings += hint($func);
  }

  unless ($opt{quiet}) {
    for $func (sort keys %{$file{uses_todo}}) {
      print "*** WARNING: Uses $func, which may not be portable below perl ",
            format_version($API{$func}{todo}), ", even with '$ppport'\n";
      $warnings++;
    }
  }

  for $func (sort keys %{$file{needed_static}}) {
    my $message = '';
    if (not exists $file{uses}{$func}) {
      $message = "No need to define NEED_$func if $func is never used";
    }
    elsif (exists $file{needs}{$func} && $file{needs}{$func} ne 'static') {
      $message = "No need to define NEED_$func when already needed globally";
    }
    if ($message) {
      diag($message);
      $file{changes} += ($c =~ s/^$HS*#$HS*define$HS+NEED_$func\b.*$LF//mg);
    }
  }

  for $func (sort keys %{$file{needed_global}}) {
    my $message = '';
    if (not exists $global{uses}{$func}) {
      $message = "No need to define NEED_${func}_GLOBAL if $func is never used";
    }
    elsif (exists $file{needs}{$func}) {
      if ($file{needs}{$func} eq 'extern') {
        $message = "No need to define NEED_${func}_GLOBAL when already needed globally";
      }
      elsif ($file{needs}{$func} eq 'static') {
        $message = "No need to define NEED_${func}_GLOBAL when only used in this file";
      }
    }
    if ($message) {
      diag($message);
      $file{changes} += ($c =~ s/^$HS*#$HS*define$HS+NEED_${func}_GLOBAL\b.*$LF//mg);
    }
  }

  $file{needs_inc_ppport} = keys %{$file{uses}};

  if ($file{needs_inc_ppport}) {
    my $pp = '';

    for $func (sort keys %{$file{needs}}) {
      my $type = $file{needs}{$func};
      next if $type eq 'extern';
      my $suffix = $type eq 'global' ? '_GLOBAL' : '';
      unless (exists $file{"needed_$type"}{$func}) {
        if ($type eq 'global') {
          diag("Files [@{$global{needs}{$func}}] need $func, adding global request");
        }
        else {
          diag("File needs $func, adding static request");
        }
        $pp .= "#define NEED_$func$suffix\n";
      }
    }

    if ($pp && ($c =~ s/^(?=$HS*#$HS*define$HS+NEED_\w+)/$pp/m)) {
      $pp = '';
      $file{changes}++;
    }

    unless ($file{has_inc_ppport}) {
      diag("Needs to include '$ppport'");
      $pp .= qq(#include "$ppport"\n)
    }

    if ($pp) {
      $file{changes} += ($c =~ s/^($HS*#$HS*define$HS+NEED_\w+.*?)^/$1$pp/ms)
                     || ($c =~ s/^(?=$HS*#$HS*include.*\Q$ppport\E)/$pp/m)
                     || ($c =~ s/^($HS*#$HS*include.*XSUB.*\s*?)^/$1$pp/m)
                     || ($c =~ s/^/$pp/);
    }
  }
  else {
    if ($file{has_inc_ppport}) {
      diag("No need to include '$ppport'");
      $file{changes} += ($c =~ s/^$HS*?#$HS*include.*\Q$ppport\E.*?$LF//m);
    }
  }

  # put back in our C comments
  my $ix;
  my $cppc = 0;
  my @ccom = @{$file{ccom}};
  for $ix (0 .. $#ccom) {
    if (!$opt{cplusplus} && $ccom[$ix] =~ s!^//!!) {
      $cppc++;
      $file{changes} += $c =~ s/$rccs$ix$rcce/$ccs$ccom[$ix] $cce/;
    }
    else {
      $c =~ s/$rccs$ix$rcce/$ccom[$ix]/;
    }
  }

  if ($cppc) {
    my $s = $cppc != 1 ? 's' : '';
    warning("Uses $cppc C++ style comment$s, which is not portable");
  }

  my $s = $warnings != 1 ? 's' : '';
  my $warn = $warnings ? " ($warnings warning$s)" : '';
  info("Analysis completed$warn");

  if ($file{changes}) {
    if (exists $opt{copy}) {
      my $newfile = "$filename$opt{copy}";
      if (-e $newfile) {
        error("'$newfile' already exists, refusing to write copy of '$filename'");
      }
      else {
        local *F;
        if (open F, ">$newfile") {
          info("Writing copy of '$filename' with changes to '$newfile'");
          print F $c;
          close F;
        }
        else {
          error("Cannot open '$newfile' for writing: $!");
        }
      }
    }
    elsif (exists $opt{patch} || $opt{changes}) {
      if (exists $opt{patch}) {
        unless ($patch_opened) {
          if (open PATCH, ">$opt{patch}") {
            $patch_opened = 1;
          }
          else {
            error("Cannot open '$opt{patch}' for writing: $!");
            delete $opt{patch};
            $opt{changes} = 1;
            goto fallback;
          }
        }
        mydiff(\*PATCH, $filename, $c);
      }
      else {
fallback:
        info("Suggested changes:");
        mydiff(\*STDOUT, $filename, $c);
      }
    }
    else {
      my $s = $file{changes} == 1 ? '' : 's';
      info("$file{changes} potentially required change$s detected");
    }
  }
  else {
    info("Looks good");
  }
}

close PATCH if $patch_opened;

exit 0;

#######################################################################

sub try_use { eval "use @_;"; return $@ eq '' }

sub mydiff
{
  local *F = shift;
  my($file, $str) = @_;
  my $diff;

  if (exists $opt{diff}) {
    $diff = run_diff($opt{diff}, $file, $str);
  }

  if (!defined $diff and try_use('Text::Diff')) {
    $diff = Text::Diff::diff($file, \$str, { STYLE => 'Unified' });
    $diff = <<HEADER . $diff;
--- $file
+++ $file.patched
HEADER
  }

  if (!defined $diff) {
    $diff = run_diff('diff -u', $file, $str);
  }

  if (!defined $diff) {
    $diff = run_diff('diff', $file, $str);
  }

  if (!defined $diff) {
    error("Cannot generate a diff. Please install Text::Diff or use --copy.");
    return;
  }

  print F $diff;
}

sub run_diff
{
  my($prog, $file, $str) = @_;
  my $tmp = 'dppptemp';
  my $suf = 'aaa';
  my $diff = '';
  local *F;

  while (-e "$tmp.$suf") { $suf++ }
  $tmp = "$tmp.$suf";

  if (open F, ">$tmp") {
    print F $str;
    close F;

    if (open F, "$prog $file $tmp |") {
      while (<F>) {
        s/\Q$tmp\E/$file.patched/;
        $diff .= $_;
      }
      close F;
      unlink $tmp;
      return $diff;
    }

    unlink $tmp;
  }
  else {
    error("Cannot open '$tmp' for writing: $!");
  }

  return undef;
}

sub rec_depend
{
  my($func, $seen) = @_;
  return () unless exists $depends{$func};
  $seen = {%{$seen||{}}};
  return () if $seen->{$func}++;
  my %s;
  grep !$s{$_}++, map { ($_, rec_depend($_, $seen)) } @{$depends{$func}};
}

sub parse_version
{
  my $ver = shift;

  if ($ver =~ /^(\d+)\.(\d+)\.(\d+)$/) {
    return ($1, $2, $3);
  }
  elsif ($ver !~ /^\d+\.[\d_]+$/) {
    die "cannot parse version '$ver'\n";
  }

  $ver =~ s/_//g;
  $ver =~ s/$/000000/;

  my($r,$v,$s) = $ver =~ /(\d+)\.(\d{3})(\d{3})/;

  $v = int $v;
  $s = int $s;

  if ($r < 5 || ($r == 5 && $v < 6)) {
    if ($s % 10) {
      die "cannot parse version '$ver'\n";
    }
  }

  return ($r, $v, $s);
}

sub format_version
{
  my $ver = shift;

  $ver =~ s/$/000000/;
  my($r,$v,$s) = $ver =~ /(\d+)\.(\d{3})(\d{3})/;

  $v = int $v;
  $s = int $s;

  if ($r < 5 || ($r == 5 && $v < 6)) {
    if ($s % 10) {
      die "invalid version '$ver'\n";
    }
    $s /= 10;

    $ver = sprintf "%d.%03d", $r, $v;
    $s > 0 and $ver .= sprintf "_%02d", $s;

    return $ver;
  }

  return sprintf "%d.%d.%d", $r, $v, $s;
}

sub info
{
  $opt{quiet} and return;
  print @_, "\n";
}

sub diag
{
  $opt{quiet} and return;
  $opt{diag} and print @_, "\n";
}

sub warning
{
  $opt{quiet} and return;
  print "*** ", @_, "\n";
}

sub error
{
  print "*** ERROR: ", @_, "\n";
}

my %given_hints;
my %given_warnings;
sub hint
{
  $opt{quiet} and return;
  my $func = shift;
  my $rv = 0;
  if (exists $warnings{$func} && !$given_warnings{$func}++) {
    my $warn = $warnings{$func};
    $warn =~ s!^!*** !mg;
    print "*** WARNING: $func\n", $warn;
    $rv++;
  }
  if ($opt{hints} && exists $hints{$func} && !$given_hints{$func}++) {
    my $hint = $hints{$func};
    $hint =~ s/^/   /mg;
    print "   --- hint for $func ---\n", $hint;
  }
  $rv;
}

sub usage
{
  my($usage) = do { local(@ARGV,$/)=($0); <> } =~ /^=head\d$HS+SYNOPSIS\s*^(.*?)\s*^=/ms;
  my %M = ( 'I' => '*' );
  $usage =~ s/^\s*perl\s+\S+/$^X $0/;
  $usage =~ s/([A-Z])<([^>]+)>/$M{$1}$2$M{$1}/g;

  print <<ENDUSAGE;

Usage: $usage

See perldoc $0 for details.

ENDUSAGE

  exit 2;
}

sub strip
{
  my $self = do { local(@ARGV,$/)=($0); <> };
  my($copy) = $self =~ /^=head\d\s+COPYRIGHT\s*^(.*?)^=\w+/ms;
  $copy =~ s/^(?=\S+)/    /gms;
  $self =~ s/^$HS+Do NOT edit.*?(?=^-)/$copy/ms;
  $self =~ s/^SKIP.*(?=^__DATA__)/SKIP
if (\@ARGV && \$ARGV[0] eq '--unstrip') {
  eval { require Devel::PPPort };
  \$@ and die "Cannot require Devel::PPPort, please install.\\n";
  if (eval \$Devel::PPPort::VERSION < $VERSION) {
    die "$0 was originally generated with Devel::PPPort $VERSION.\\n"
      . "Your Devel::PPPort is only version \$Devel::PPPort::VERSION.\\n"
      . "Please install a newer version, or --unstrip will not work.\\n";
  }
  Devel::PPPort::WriteFile(\$0);
  exit 0;
}
print <<END;

Sorry, but this is a stripped version of \$0.

To be able to use its original script and doc functionality,
please try to regenerate this file using:

  \$^X \$0 --unstrip

END
/ms;
  my($pl, $c) = $self =~ /(.*^__DATA__)(.*)/ms;
  $c =~ s{
    / (?: \*[^*]*\*+(?:[^$ccs][^*]*\*+)* / | /[^\r\n]*)
  | ( "[^"\\]*(?:\\.[^"\\]*)*"
    | '[^'\\]*(?:\\.[^'\\]*)*' )
  | ($HS+) }{ defined $2 ? ' ' : ($1 || '') }gsex;
  $c =~ s!\s+$!!mg;
  $c =~ s!^$LF!!mg;
  $c =~ s!^\s*#\s*!#!mg;
  $c =~ s!^\s+!!mg;

  open OUT, ">$0" or die "cannot strip $0: $!\n";
  print OUT "$pl$c\n";

  exit 0;
}