emoji-to-hex-3.php

<?
require('emoji_unicode.php');

$text = "hello :world_map: . it's :hammer: :stopwatch:.";

//alphanumeric, hyphens, plus-signs, and underscores string, wrapped in colons
preg_match_all("/:([a-zA-Z0-9'_+-]+):/", $text, $emojis);

foreach ($emojis[1] as $emojiname)
  if (isset($emoji_unicode[$emojiname]))
    $text = str_replace(":".$emojiname.":", "&#x".$emoji_unicode[$emojiname].";", $text);
  else 
    $text = str_replace(":".$emojiname.":", "(".$emojiname.")", $text);

echo $text;
?>