function Markdown_Parser::encodeEmailAddress in Markdown 5

Same name and namespace in other branches

1. 6 markdown.php \Markdown_Parser::encodeEmailAddress()

1 call to Markdown_Parser::encodeEmailAddress()

Markdown_Parser::_doAutoLinks_email_callback in ./markdown.php

File

./markdown.php, line 1445

Class

Markdown_Parser

Code

function encodeEmailAddress($addr) {

  #

  #	Input: an email address, e.g. "foo@example.com"

  #

  #	Output: the email address as a mailto link, with each character

  #		of the address encoded as either a decimal or hex entity, in

  #		the hopes of foiling most address harvesting spam bots. E.g.:

  #

  #	  <p><a href="&#109;&#x61;&#105;&#x6c;&#116;&#x6f;&#58;&#x66;o&#111;

  #        &#x40;&#101;&#x78;&#97;&#x6d;&#112;&#x6c;&#101;&#46;&#x63;&#111;

  #        &#x6d;">&#x66;o&#111;&#x40;&#101;&#x78;&#97;&#x6d;&#112;&#x6c;

  #        &#101;&#46;&#x63;&#111;&#x6d;</a></p>

  #

  #	Based by a filter by Matthew Wickline, posted to BBEdit-Talk.

  #   With some optimizations by Milian Wolff.

  #
  $addr = "mailto:" . $addr;
  $chars = preg_split('/(?<!^)(?!$)/', $addr);
  $seed = (int) abs(crc32($addr) / strlen($addr));

  # Deterministic seed.
  foreach ($chars as $key => $char) {
    $ord = ord($char);

    # Ignore non-ascii chars.
    if ($ord < 128) {
      $r = $seed * (1 + $key) % 100;

      # Pseudo-random function.

      # roughly 10% raw, 45% hex, 45% dec

      # '@' *must* be encoded. I insist.
      if ($r > 90 && $char != '@') {

        /* do nothing */
      }
      else {
        if ($r < 45) {
          $chars[$key] = '&#x' . dechex($ord) . ';';
        }
        else {
          $chars[$key] = '&#' . $ord . ';';
        }
      }
    }
  }
  $addr = implode('', $chars);
  $text = implode('', array_slice($chars, 7));

  # text without `mailto:`
  $addr = "<a href=\"{$addr}\">{$text}</a>";
  return $addr;
}