PHP 生成 UUID 函数

generate name based md5 uuid (version 3)

/**
 * generate name based md5 uuid (version 3).
 * @example '7e57d004-2b97-0e7a-b45f-5387367791cd'
 */
public function uuid()
{
    // fix for compatibility with 32bit architecture; seed range restricted to 62bit
    $seed = mt_rand(0, 2147483647) . '#' . mt_rand(0, 2147483647);

    // hash the seed and convert to a byte array
    $val = md5($seed, true);
    $byte = array_values(unpack('c16', $val));

    // extract fields from byte array
    $tlo = ($byte[0] << 24) | ($byte[1] << 16) | ($byte[2] << 8) | $byte[3];
    $tmi = ($byte[4] << 8) | $byte[5];
    $thi = ($byte[6] << 8) | $byte[7];
    $cslo = $byte[9];
    $cshi = $byte[8] & 0x3f | (1 << 7);

    // correct byte order for big edian architecture
    if (pack('l', 0x6162797a) == pack('n', 0x6162797a)) {
        $tlo = (($tlo & 0x000000ff) << 24) | (($tlo & 0x0000ff00) << 8)
            | (($tlo & 0x00ff0000) >> 8) | (($tlo & 0xff000000) >> 24);
        $tmi = (($tmi & 0x00ff) << 8) | (($tmi & 0xff00) >> 8);
        $thi = (($thi & 0x00ff) << 8) | (($thi & 0xff00) >> 8);
    }

    // apply version number
    $thi &= 0x0fff;
    $thi |= (3 << 12);

    // cast to string
    $uuid = sprintf(
        '%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x',
        $tlo,
        $tmi,
        $thi,
        $cshi,
        $cslo,
        $byte[10],
        $byte[11],
        $byte[12],
        $byte[13],
        $byte[14],
        $byte[15]
    );

    return $uuid;
}

函数来源：fzaninotto/faker

地址：https://github.com/fzaninotto/faker