source code
<?hh
/* The Computer Language Benchmarks Game
http://benchmarksgame.alioth.debian.org/
contributed by Isaac Gouy
PHP as HHVM/Hack by Isaac Gouy
php -q pidigits.php 27
*/
class Transformation {
var $q, $r, $s, $t, $k;
function Transformation($q, $r, $s, $t){
$this->q = $q;
$this->r = $r;
$this->s = $s;
$this->t = $t;
}
function Unity(){
return new Transformation("1", "0", "0", "1");
}
function Zero(){
return new Transformation("0", "0", "0", "0");
}
function Compose($a){
$qq = bcmul($this->q, $a->q);
$qrrt = bcadd(bcmul($this->q, $a->r), bcmul($this->r, $a->t));
$sqts = bcadd(bcmul($this->s, $a->q), bcmul($this->t, $a->s));
$srtt = bcadd(bcmul($this->s, $a->r), bcmul($this->t, $a->t));
return new Transformation($qq, $qrrt, $sqts, $srtt);
}
function Extract($j){
$bigj = strval($j);
$qjr = bcadd(bcmul($this->q, $bigj), $this->r);
$sjt = bcadd(bcmul($this->s, $bigj), $this->t);
$d = bcdiv($qjr, $sjt);
return floor($d);
}
function Next(){
$this->k = $this->k + 1;
$this->q = strval($this->k);
$this->r = strval(4*$this->k + 2);
$this->s = "0";
$this->t = strval(2*$this->k + 1);
return $this;
}
}
class PiDigitStream {
var $z, $x, $inverse;
function PiDigitStream(){
$this->z = Transformation::Unity();
$this->x = Transformation::Zero();
$this->inverse = Transformation::Zero();
}
function Produce($j){
$i = $this->inverse;
$i->q = "10";
$i->r = strval(-10*$j);
$i->s = "0";
$i->t = "1";
return $i->Compose($this->z);
}
function Consume($a){
return $this->z ->Compose($a);
}
function Digit(){
return $this->z ->Extract(3);
}
function IsSafe($j){
return $j == ($this->z ->Extract(4));
}
function Next(){
$y = $this->Digit();
if ($this->IsSafe($y)){
$this->z = $this->Produce($y);
return $y;
} else {
$this->z = $this->Consume($this->x ->Next());
return $this->Next();
}
}
}
$n = $argv[1];
$i = 0;
$length = 10;
$pidigit = new PiDigitStream;
while ($n > 0){
if ($n < $length){
for ($j=0; $j<$n; $j++) printf("%d",$pidigit->Next());
for ($j=$n; $j<$length; $j++) print " ";
$i += $n;
} else {
for ($j=0; $j<$length; $j++) printf("%d",$pidigit->Next());
$i += $length;
}
print "\t:$i\n";
$n -= $length;
}