class UuidPhp

backdrop_class_list in core/includes/bootstrap.classes.inc

Lists all the classes used by Backdrop core.

Uuid::determinePlugin in core/includes/uuid.inc

Determines the optimal implementation to use for generating UUIDs.

class UuidPhp implements UuidInterface {
  public function generate() {
    $hex = substr(hash('sha256', backdrop_random_bytes(16)), 0, 32);

    // The field names refer to RFC 4122 section 4.1.2.
    $time_low = substr($hex, 0, 8);
    $time_mid = substr($hex, 8, 4);

    $time_hi_and_version = base_convert(substr($hex, 12, 4), 16, 10);
    $time_hi_and_version &= 0x0FFF;
    $time_hi_and_version |= (4 << 12);

    $clock_seq_hi_and_reserved = base_convert(substr($hex, 16, 4), 16, 10);
    $clock_seq_hi_and_reserved &= 0x3F;
    $clock_seq_hi_and_reserved |= 0x80;

    $clock_seq_low = substr($hex, 20, 2);
    $nodes = substr($hex, 20);

    $uuid = sprintf('%s-%s-%04x-%02x%02x-%s', 
    $time_low, $time_mid, 
    $time_hi_and_version, $clock_seq_hi_and_reserved, 
    $clock_seq_low, $nodes);

    return $uuid;
  }
}