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RNG: XorShift128 adapted from php-random library

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Fixes world generation problems on 32-bit systems
This commit is contained in:
Tatsuyuki Ishi 2016-09-01 23:48:55 +09:00 committed by Dylan K. Taylor
parent b156480550
commit a3e3a5f631
1 changed files with 44 additions and 10 deletions
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54
src/pocketmine/utils/Random.php
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@ -21,11 +21,35 @@
namespace pocketmine\utils;
/**
* Unsecure Random Number Noise, used for fast seeded values
* XorShift128Engine Random Number Noise, used for fast seeded values
* Most of the code in this class was adapted from the XorShift128Engine in the php-random library.
*/
class Random{
const X = 123456789;
const Y = 362436069;
const Z = 521288629;
const W = 88675123;
/**
* @var int
*/
private $x;
/**
* @var int
*/
private $y;
/**
* @var int
*/
private $z;
/**
* @var int
*/
private $w;
protected $seed;
@ -33,7 +57,7 @@ class Random{
* @param int $seed Integer to be used as seed.
*/
public function __construct($seed = -1){
if($seed == -1){
if($seed === -1){
$seed = time();
}
@ -44,7 +68,15 @@ class Random{
* @param int $seed Integer to be used as seed.
*/
public function setSeed($seed){
$this->seed = crc32(pack("N", $seed));
$this->seed = $seed;
$this->x = self::X ^ $seed;
$this->y = self::Y ^ ($seed << 17) | (($seed >> 15) & 0x7fffffff) & 0xffffffff;
$this->z = self::Z ^ ($seed << 31) | (($seed >> 1) & 0x7fffffff) & 0xffffffff;
$this->w = self::W ^ ($seed << 18) | (($seed >> 14) & 0x7fffffff) & 0xffffffff;
}
public function getSeed(){
return $this->seed;
}
/**
@ -62,13 +94,15 @@ class Random{
* @return int
*/
public function nextSignedInt(){
$t = ((($this->seed * 65535) + 31337) >> 8) + 1337;
if(PHP_INT_SIZE === 8){
$t = $t << 32 >> 32;
}
$this->seed ^= $t;
$t = ($this->x ^ ($this->x << 11)) & 0xffffffff;
return $t;
$this->x = $this->y;
$this->y = $this->z;
$this->z = $this->w;
$this->w = ($this->w ^ (($this->w >> 19) & 0x7fffffff)
^ ($t ^ (($t >> 8) & 0x7fffffff))) & 0xffffffff;
return $this->w;
}
/**