header(‘Content-type:text/html;Charset=UTF-8‘);define(‘blockSize‘, 4*1024*1024);var_dump(fileHash(‘test.wmv‘));var_dump(fileHash(‘asdf.wmv‘));function fileHash($file){    $f = fopen($file, "r");    if (!$f) exit("open $file error");    $fileSize = filesize($file);    $buffer   = ‘‘;    $sha      = ‘‘;    // 一共有多少分片    $blkcnt   = $fileSize/blockSize;    if ($fileSize % blockSize) $blkcnt += 1;    // 把数据装入一个二进制字符串    $buffer .= pack("L", $blkcnt);    if ($fileSize <= blockSize) {        $content = fread($f, blockSize);        if (!$content) {            fclose($f);            exit("read file error");        }        $sha .= sha1($content, TRUE);    } else {        for($i=0; $i<$blkcnt; $i+=1) {            $content = fread($f, blockSize);            if (!$content) {                if (feof($f)) break;                fclose($f);                exit("read file error");            }            $sha .= sha1($content, TRUE);        }        $sha = sha1($sha, TRUE);    }    $buffer .= $sha;    $hash = urlSafeEncode(base64_encode($buffer));    fclose($f);    return array($hash, null);}function urlSafeEncode($data){    $find = array(‘+‘, ‘/‘);    $replace = array(‘-‘, ‘_‘);    return str_replace($find, $replace, $data);}