function Php::generate
Same name in other branches
- 8.9.x core/lib/Drupal/Component/Uuid/Php.php \Drupal\Component\Uuid\Php::generate()
- 10 core/lib/Drupal/Component/Uuid/Php.php \Drupal\Component\Uuid\Php::generate()
- 11.x core/lib/Drupal/Component/Uuid/Php.php \Drupal\Component\Uuid\Php::generate()
Overrides UuidInterface::generate
File
-
core/
lib/ Drupal/ Component/ Uuid/ Php.php, line 16
Class
- Php
- Generates a UUID v4 (RFC 4122 section 4.4) using PHP code.
Namespace
Drupal\Component\UuidCode
public function generate() {
// Obtain a random string of 32 hex characters.
$hex = bin2hex(random_bytes(16));
// The variable names $time_low, $time_mid, $time_hi_and_version,
// $clock_seq_hi_and_reserved, $clock_seq_low, and $node correlate to
// the fields defined in RFC 4122 section 4.1.2.
//
// Use characters 0-11 to generate 32-bit $time_low and 16-bit $time_mid.
$time_low = substr($hex, 0, 8);
$time_mid = substr($hex, 8, 4);
// Use characters 12-15 to generate 16-bit $time_hi_and_version.
// The 4 most significant bits are the version number (0100 == 0x4).
// We simply skip character 12 from $hex, and concatenate the strings.
$time_hi_and_version = '4' . substr($hex, 13, 3);
// Use characters 16-17 to generate 8-bit $clock_seq_hi_and_reserved.
// The 2 most significant bits are set to one and zero respectively.
$clock_seq_hi_and_reserved = base_convert(substr($hex, 16, 2), 16, 10);
$clock_seq_hi_and_reserved &= 0b111111;
$clock_seq_hi_and_reserved |= 0b10000000;
// Use characters 18-19 to generate 8-bit $clock_seq_low.
$clock_seq_low = substr($hex, 18, 2);
// Use characters 20-31 to generate 48-bit $node.
$node = substr($hex, 20);
// Re-combine as a UUID. $clock_seq_hi_and_reserved is still an integer.
$uuid = sprintf('%s-%s-%s-%02x%s-%s', $time_low, $time_mid, $time_hi_and_version, $clock_seq_hi_and_reserved, $clock_seq_low, $node);
return $uuid;
}
Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.