Online PHP editor | refs for BMcRN

<?php class PseudoRandomSequence { const STATE_HASH = "sha512"; // 1/2 STATE_HASH block size, const STATE_SIZE = 32; private $state; public function __construct($state) { $this->state = $state; $this->mixState(); } public function int($min = 0, $max = PHP_INT_MAX) { $range = $max - $min; if ($range <= 0 || is_float($range)) { throw new Exception("Invalid min/max provided"); } $bits = 1; $tmp = $range; while ($tmp >>= 1) { $bits++; } $bytes = (int) max(ceil($bits / 8), 1); $mask = (int) (pow(2, $bits) - 1); if ($mask < 0) { // Hack since PHP will upcast 2^63-1 into a negative number $mask = PHP_INT_MAX; } do { $rand = hexdec(bin2hex(substr($this->bytes(8), 0, $bytes))); $result = $rand & $mask; } while ($result > $range); return $result + $min; } public function bytes($n) { $ret = ''; do { $ret .= $this->mixState(); } while (strlen($ret) < $n); return substr($ret, 0, $n); } private function mixState() { $hash = hash(self::STATE_HASH, $this->state, true); $this->state = substr($hash, 0, self::STATE_SIZE); echo('state changed'); return substr($hash, self::STATE_SIZE); } } $prng = new PseudoRandomSequence("test"); $prng->int(0,99);