CascadiaPHP 2024


(PHP 8 >= 8.2.0)

Random\Engine\Xoshiro256StarStar::__constructConstructs a new xoshiro256** engine


public Random\Engine\Xoshiro256StarStar::__construct(string|int|null $seed = null)


This function is currently not documented; only its argument list is available.



How the internal 256 bit (32 byte) state consisting of four unsigned 64 bit integers is seeded depends on the type used as the seed.

Type Description
null Fills the state with 32 random bytes generated using the CSPRNG.
int Fills the state with four consecutive values generated with the SplitMix64 algorithm that was seeded with seed interpreted as an unsigned 64 bit integer.
string Fills the state by interpreting a 32 byte string as four little-endian unsigned 64 bit integers.



Example #1 Random\Engine\Xoshiro256StarStar::__construct() example

// Uses a random 256 Bit seed.
$e = new \Random\Engine\Xoshiro256StarStar();

$r = new \Random\Randomizer($e);

Example #2 Deriving a seed from a string

= "My string seed";

// Hash the string with SHA-256 using binary output to turn the
// $string into a 256 Bit seed. Using the same string will result
// in the same sequence of randomness.
$e = new \Random\Engine\Xoshiro256StarStar(
hash('sha256', $string, binary: true)

bin2hex($e->generate()), "\n";

The above example will output:

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