php递归去除bom头信息

    因为本人才疏学浅，对问题认知不免有误差，本着学习与共享的精神和你们一块儿探讨，如有不对之处，望你们多多批评指正。

<?php
//author:马荣财
//EF BB BF这三个字节称为bom头
function hasbom(&$content) {
    $firstline = $content[0];
    return ord(substr($firstline, 0, 1)) === 0xEF
        and ord(substr($firstline, 1, 1)) === 0xBB
        and ord(substr($firstline, 2, 1)) === 0xBF;
}
function unsetbom(&$content) {
    hasbom($content) and ($content[0] = substr($content[0], 3));
    echo '该文件有bom头标';
}
function write($filename, &$content) {
    $file = fopen($filename, 'w');
    fwrite($file, implode($content, ''));
    fclose($file);
}
function filenames($path) {
    $directory = opendir($path);
    while (false != ($filename = readdir($directory))) strpos($filename, '.') !== 0 and $filenames[] = $filename;
    closedir($directory);
    return $filenames;
}
function process($path) {
    $parent = opendir($path);
    while (false != ($filename = readdir($parent))) {
       echo $filename."/n";
        if(strpos($filename, '.') === 0) continue;
        if(is_dir($path.DIRECTORY_SEPARATOR.$filename)) {
            process($path.DIRECTORY_SEPARATOR.$filename);
        } else {
            $content = file($path.DIRECTORY_SEPARATOR.$filename);
            unsetbom($content);
            write($path.DIRECTORY_SEPARATOR .$filename, $content);
        }
    }
    closedir($parent);
}
process('/tmp/mrc');
?>