eval 'exec perl "$0" "$1" "$2"'
  if $running_under_some_shell;
use File::Find 'find';

# Build a (sorted) EMACS / VI(M) tags file including GP functions
#
$emacs_mode = ($ARGV[0] eq "--emacs");
$src = $ARGV[1];

if ($emacs_mode)
{ $tags = "$src/TAGS"; }
else
# Case sensitive?
{ $tags = $^O eq 'os2' ? "$src/ctags" : "$src/tags"; }
$tmptags = "$tags.tmp";

my (%gp);
getnames("$src/gp/gp_init.h");
getnames("$src/language/init.h");

my (@files) = (); find \&filter_c, $src;
@tags = "";
if ($emacs_mode) {
  system('exuberant-ctags', '-e', '-f', $tmptags, @files)
    && system('ctags-exuberant', '-e', '-f', $tmptags, @files)
    && system('etags', '-f', $tmptags, @files)
    && die("etags failed");
  open(T,"$tmptags");

  while(<T>) {
    my ($a,$b);
    $a = $_;
    if (/^(\w+)\(/ && ($b = $gp{$1}) && $b ne $1)
    {
      $a =~ s/\x7F.*\x01/\x7F$b\x01/;
      push(@tags,$a);
    }
    push(@tags,$_);
  }
} else {
  system('exuberant-ctags', '-f', $tmptags, @files)
    && system('ctags-exuberant', '-f', $tmptags, @files)
    && system('ctags', '-f', $tmptags, @files)
    && system('ctags', '-dT', '-o', $tmptags, @files) # gctags
    && die("ctags failed");
  open(T,"$tmptags");

  # Assume ctags outputs sorted tags (e.g Exuberant Ctags)
  my ($old) = "";
  for (sort(keys %gp)) {
    my ($a) = $_;
    my ($b) = $gp{$a};
    if ($a eq $old) { push(@tags,"$b$rest\n"); next; }
    $old = $a;
    while(<T>)
    {
      push(@tags,$_);
      if (/^$a(.*)/) { $rest="$1"; push(@tags,"$b$rest\n"); last; }
    }
  }
  while(<T>) { push(@tags,$_); }
  @tags = sort(@tags);
}
close(T);
open(OUT,">$tags");
print OUT @tags;
unlink $tmptags;

# $gp{GP_function} = C_function
sub getnames
{
  open(A,$_[0]);
  while (<A>) {
    if (/^entree functions_/../^$/) {
      if (/[^"]*"([^"]*)".*\(void\*\) *([^,]*)/)
      {
        my ($gpfun, $cfun) = ($1,$2);
        $gpfun =~ s/_\.//g; # member functions
        $gp{$cfun} = $gpfun;
      }
    }
  }
  close(A);
}

sub filter_c {
  return unless /\.[chy]\Z/ && -f;
  return if (/(dummy|tune|kerntest|parse)\.c/);
  push @files, "$File::Find::name";
}
