file_get_contents with detect any UTF or one specified 8-bit encoding (default Windows-1251)

gistfile1.php

<?php

file_get_contents_utf_ansi($filename, $defAnsiEnc = 'Windows-1251')
{
    $buf = file_get_contents($filename);

    if      (substr($buf, 0, 3) == "\xEF\xBB\xBF")          return substr($buf,3);
    else if (substr($buf, 0, 2) == "\xFE\xFF")              return mb_convert_encoding(substr($buf, 2), 'UTF-8', 'UTF-16BE');
    else if (substr($buf, 0, 2) == "\xFF\xFE")              return mb_convert_encoding(substr($buf, 2), 'UTF-8', 'UTF-16LE');
    else if (substr($buf, 0, 4) == "\x00\x00\xFE\xFF")      return mb_convert_encoding(substr($buf, 4), 'UTF-8', 'UTF-32BE');
    else if (substr($buf, 0, 4) == "\xFF\xFE\x00\x00")      return mb_convert_encoding(substr($buf, 4), 'UTF-8', 'UTF-32LE');
    else if (mb_detect_encoding(trim($buf), $defAnsiEnc)
        || utf8_encode(utf8_decode($buf)) != $buf)          return mb_convert_encoding($buf, 'UTF-8', $defAnsiEnc);
    else                                                    return $buf;
}

Seems that UTF-32LE will be detected as UTF-16LE because of the order of the tests.
Very interesting function though. Got it! ;)