#!/usr/bin/perl -w
  #
  # Build a static ASN.1 Object Identified (OID) registry
  #
  # Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
  # Written by David Howells (dhowells@redhat.com)
  #
  # This program is free software; you can redistribute it and/or
  # modify it under the terms of the GNU General Public Licence
  # as published by the Free Software Foundation; either version
  # 2 of the Licence, or (at your option) any later version.
  #
  
  use strict;
  
  my @names = ();
  my @oids = ();
  
  if ($#ARGV != 1) {
      print STDERR "Format: ", $0, " <in-h-file> <out-c-file>
  ";
      exit(2);
  }
  
  #
  # Open the file to read from
  #
  open IN_FILE, "<$ARGV[0]" || die;
  while (<IN_FILE>) {
      chomp;
      if (m!\s+OID_([a-zA-z][a-zA-Z0-9_]+),\s+/[*]\s+([012][.0-9]*)\s+[*]/!) {
  	push @names, $1;
  	push @oids, $2;
      }
  }
  close IN_FILE || die;
  
  #
  # Open the files to write into
  #
  open C_FILE, ">$ARGV[1]" or die;
  print C_FILE "/*
  ";
  print C_FILE " * Automatically generated by ", $0, ".  Do not edit
  ";
  print C_FILE " */
  ";
  
  #
  # Split the data up into separate lists and also determine the lengths of the
  # encoded data arrays.
  #
  my @indices = ();
  my @lengths = ();
  my $total_length = 0;
  
  for (my $i = 0; $i <= $#names; $i++) {
      my $name = $names[$i];
      my $oid = $oids[$i];
  
      my @components = split(/[.]/, $oid);
  
      # Determine the encoded length of this OID
      my $size = $#components;
      for (my $loop = 2; $loop <= $#components; $loop++) {
  	my $c = $components[$loop];
  
  	# We will base128 encode the number
  	my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
  	$tmp = int($tmp / 7);
  	$size += $tmp;
      }
      push @lengths, $size;
      push @indices, $total_length;
      $total_length += $size;
  }
  
  #
  # Emit the look-up-by-OID index table
  #
  print C_FILE "
  ";
  if ($total_length <= 255) {
      print C_FILE "static const unsigned char oid_index[OID__NR + 1] = {
  ";
  } else {
      print C_FILE "static const unsigned short oid_index[OID__NR + 1] = {
  ";
  }
  for (my $i = 0; $i <= $#names; $i++) {
      print C_FILE "\t[OID_", $names[$i], "] = ", $indices[$i], ",
  "
  }
  print C_FILE "\t[OID__NR] = ", $total_length, "
  ";
  print C_FILE "};
  ";
  
  #
  # Encode the OIDs
  #
  my @encoded_oids = ();
  
  for (my $i = 0; $i <= $#names; $i++) {
      my @octets = ();
  
      my @components = split(/[.]/, $oids[$i]);
  
      push @octets, $components[0] * 40 + $components[1];
  
      for (my $loop = 2; $loop <= $#components; $loop++) {
  	my $c = $components[$loop];
  
  	# Base128 encode the number
  	my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
  	$tmp = int($tmp / 7);
  
  	for (; $tmp > 0; $tmp--) {
  	    push @octets, (($c >> $tmp * 7) & 0x7f) | 0x80;
  	}
  	push @octets, $c & 0x7f;
      }
  
      push @encoded_oids, \@octets;
  }
  
  #
  # Create a hash value for each OID
  #
  my @hash_values = ();
  for (my $i = 0; $i <= $#names; $i++) {
      my @octets = @{$encoded_oids[$i]};
  
      my $hash = $#octets;
      foreach (@octets) {
  	$hash += $_ * 33;
      }
  
      $hash = ($hash >> 24) ^ ($hash >> 16) ^ ($hash >> 8) ^ ($hash);
  
      push @hash_values, $hash & 0xff;
  }
  
  #
  # Emit the OID data
  #
  print C_FILE "
  ";
  print C_FILE "static const unsigned char oid_data[", $total_length, "] = {
  ";
  for (my $i = 0; $i <= $#names; $i++) {
      my @octets = @{$encoded_oids[$i]};
      print C_FILE "\t";
      print C_FILE $_, ", " foreach (@octets);
      print C_FILE "\t// ", $names[$i];
      print C_FILE "
  ";
  }
  print C_FILE "};
  ";
  
  #
  # Build the search index table (ordered by length then hash then content)
  #
  my @index_table = ( 0 .. $#names );
  
  @index_table = sort {
      my @octets_a = @{$encoded_oids[$a]};
      my @octets_b = @{$encoded_oids[$b]};
  
      return $hash_values[$a] <=> $hash_values[$b]
  	if ($hash_values[$a] != $hash_values[$b]);
      return $#octets_a <=> $#octets_b
  	if ($#octets_a != $#octets_b);
      for (my $i = $#octets_a; $i >= 0; $i--) {
  	return $octets_a[$i] <=> $octets_b[$i]
  	    if ($octets_a[$i] != $octets_b[$i]);
      }
      return 0;
  
  } @index_table;
  
  #
  # Emit the search index and hash value table
  #
  print C_FILE "
  ";
  print C_FILE "static const struct {
  ";
  print C_FILE "\tunsigned char hash;
  ";
  if ($#names <= 255) {
      print C_FILE "\tenum OID oid : 8;
  ";
  } else {
      print C_FILE "\tenum OID oid : 16;
  ";
  }
  print C_FILE "} oid_search_table[OID__NR] = {
  ";
  for (my $i = 0; $i <= $#names; $i++) {
      my @octets = @{$encoded_oids[$index_table[$i]]};
      printf(C_FILE "\t[%3u] = { %3u, OID_%-35s }, // ",
  	   $i,
  	   $hash_values[$index_table[$i]],
  	   $names[$index_table[$i]]);
      printf C_FILE "%02x", $_ foreach (@octets);
      print C_FILE "
  ";
  }
  print C_FILE "};
  ";
  
  #
  # Emit the OID debugging name table
  #
  #print C_FILE "
  ";
  #print C_FILE "const char *const oid_name_table[OID__NR + 1] = {
  ";
  #
  #for (my $i = 0; $i <= $#names; $i++) {
  #    print C_FILE "\t\"", $names[$i], "\",
  "
  #}
  #print C_FILE "\t\"Unknown-OID\"
  ";
  #print C_FILE "};
  ";
  
  #
  # Polish off
  #
  close C_FILE or die;