Convert tis-620 to utf-8 text function (for legacy data from database).

gistfile1.php

<?php
function tis620_to_utf8($text) {
  $utf8 = "";
  for ($i = 0; $i < strlen($text); $i++) {
    $a = substr($text, $i, 1);
    $val = ord($a);

    if ($val < 0x80) {
      $utf8 .= $a;
    } elseif ((0xA1 <= $val && $val < 0xDA) || (0xDF <= $val && $val <= 0xFB)) {
      $unicode = 0x0E00+$val-0xA0; $utf8 .= chr(0xE0 | ($unicode >> 12));
      $utf8 .= chr(0x80 | (($unicode >> 6) & 0x3F));
      $utf8 .= chr(0x80 | ($unicode & 0x3F));
    }
  }
  return $utf8;
}