<?php
######################################################################################
#                                                                                    #
# RFC822 Email Parser                                                                #
# http://code.iamcal.com/php/rfc822/rfc822.phps                                      #
#                                                                                    #
# By Cal Henderson <cal@iamcal.com>                                                  #
# This code is licensed under a Creative Commons Attribution-ShareAlike 2.5 License  #
# http://creativecommons.org/licenses/by-sa/2.5/                                     #
#                                                                                    #
# Revision 2                                                                         #
#                                                                                    #
######################################################################################


function is_valid_email_address($email){
    $qtext = '[^\\x0d\\x22\\x5c\\x80-\\xff]';
    $dtext = '[^\\x0d\\x5b-\\x5d\\x80-\\xff]';
    $char = '[^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c'.
              '\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]';
    $atom = "$char+";

          $quoted_pair = '\\x5c[\\x00-\\x7f]';
          $domain_literal = "\\x5b($dtext|$quoted_pair)*\\x5d";
          $quoted_string = "\\x22($qtext|$quoted_pair)*\\x22";
          $domain_ref = $atom;
          $top_domain = "[a-zA-Z]{2,10}";
          $sub_domain = "($domain_ref|$domain_literal)";
          $word = "($atom|$quoted_string)";
          $domain = "$sub_domain(\\x2e$sub_domain)*\\x2e$top_domain";
          $local_part = "$word(\\x2e$word)*";
          $addr_spec = "$local_part\\x40$domain";
          return preg_match("!^$addr_spec$!", $email) ? 1 : 0;
      }

?>