public function UuidPhp::generate

Generates a Universally Unique IDentifier (UUID).

Return value

A 32 byte integer represented as a hex string formatted with 4 hyphens.:

Overrides UuidInterface::generate

File

core/includes/uuid.inc, line 128

Handling of universally unique identifiers.

Class

UuidPhp

Generates an UUID v4 using PHP code.

Code

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;
}