Revision e31fd16d-c033-449c-866a-10a2dfefe2d8 - Stack Overflow

I have a JS function, with array inputs.<br><br>For example:
> x=[ 239709880, 250229420, 109667654, 196414465, 13098 ]<br>
> y=[ 78135241, 54642792, 249 ]

OR:
> x=[ 0, 0, 0, 0, 0, 0, 1 ]<br>
> y=[ 78135241, 54642792, 249 ]

OR:
> x=[ 49 ]<br>
> y=[ 33 ]


``` lang-js
function bdiv(x,y) {
	var n=x.length-1, t=y.length-1, nmt=n-t, arr = []
	if(n < t || n==t && (x[n]<y[n] || n>0 && x[n]==y[n] && x[n-1]<y[n-1])) {
		arr['q']=[0]
		arr['mod']=x
		return arr
	}
	if(n==t && toppart(x,t,2)/toppart(y,t,2) <4) {
		var q=0, xx
		for(;;) {
			xx=bsub(x,y)
			if(xx.length==0) break
			x=xx; q++
		}
		arr['q']=[q]
		arr['mod']=x
		return arr
	}
	var shift, shift2
	shift2=Math.floor(Math.log(y[t])/log2)+1
	shift=bs-shift2

	if(shift) {
		x=x.concat()
		y=y.concat()
		for(i=t; i>0; i--) y[i]=((y[i]<<shift) & bm) | (y[i-1] >> shift2); y[0]=(y[0]<<shift) & bm
		if(x[n] & ((bm <<shift2) & bm)) { x[++n]=0; nmt++; }
		for(i=n; i>0; i--) x[i]=((x[i]<<shift) & bm) | (x[i-1] >> shift2); x[0]=(x[0]<<shift) & bm
	}
	var i, j, x2, y2,q=zeros(nmt+1)

	y2=zeros(nmt).concat(y)

	for(;;) {
		x2=bsub(x,y2)
		if(x2.length==0) break
		q[nmt]++
		x=x2
	}
	var yt=y[t], top=toppart(y,t,2)
	for(i=n; i>t; i--) {
		m=i-t-1
		if(i >= x.length)
			q[m]=1
		else if(x[i] == yt)
			q[m]=bm
		else
			q[m]=Math.floor(toppart(x,i,2)/yt)
		topx=toppart(x,i,3)
		while(q[m] * top > topx)
			q[m]--
		y2=y2.slice(1)
		x2=bsub(x,bmul([q[m]],y2))
		if(x2.length==0) {
			q[m]--
			x2=bsub(x,bmul([q[m]],y2))
		}
		x=x2
	}
	if(shift){
		for(i=0; i<x.length-1; i++)
			x[i]=(x[i]>>shift) | ((x[i+1] << shift2) & bm);
		x[x.length-1]>>=shift
	}
	while(q.length > 1 && q[q.length-1]==0)
		q=q.slice(0,q.length-1)
	while(x.length > 1 && x[x.length-1]==0)
		x=x.slice(0,x.length-1)
	arr['q']=q
	arr['mod']=x
	return arr;
}
```

<br>What I have done under 5 days so far in PHP:<br><br>

``` lang-php
function bdiv($x,$y){
	global $bs, $bm, $bx2, $bx, $bd, $bdm, $log2;
	$arr=[];
	$n=count($x)-1;
	$t=count($y)-1;
	$nmt=$n-$t;

	if($n < $t || $n==$t && ($x[$n]<$y[$n] || $n>0 && $x[$n]==$y[$n] && $x[$n-1]<$y[$n-1]))
		return ['q'=>[0], 'mod'=>$x];

	if($n==$t && toppart($x,$t,2)/toppart($y,$t,2) <4){
		$q=0;
		for(;;){
			$xx=bsub($x,$y);
			if(count($xx)==0)
				break;
			$x=$xx;
			$q++;
		}
		return ['q'=>[$q], 'mod'=>$x];
	}

	$shift2=floor(log($y[$t])/$log2)+1;
	$shift=$bs-$shift2;
	if($shift){

/////////////////////////////////////////////////// the problem start here with the concat()
		array_push($x,$x);
		array_push($y,$y);

		for($i=$t; $i>0; $i--)
			$y[$i]=(($y[$i] << $shift) & $bm) | ($y[$i-1] >> $shift2);
		$y[0]=($y[0] << $shift) & $bm;
		if($x[$n] & (($bm << $shift2) & $bm)){
			$x[++$n]=0;
			$nmt++;
		}
		for($i=$n; $i > 0; $i--)
			$x[$i]=(($x[$i] << $shift) & $bm) | ($x[$i-1] >> $shift2);
		$x[0]=($x[0] << $shift) & $bm;
	}
	$q=zeros($nmt+1);

	array_push($arr, zeros($nmt));
	array_push($arr, $y);
	$y2=array_merge(...$arr);

	for(;;){
		$x2=bsub($x,$y2);
		if(count($x2)==0)
			break;
		$q[$nmt]++;
		$x=$x2;
	}

	$yt=$y[$t];
	$top=toppart($y,$t,2);

	for($i=$n; $i>$t; $i--){
		$m=$i-$t-1;
		if($i >= count($x))
			$q[$m]=1;
		else if($x[$i] == $yt)
			$q[$m]=$bm;
		else
			$q[$m]=floor(toppart($x,$i,2)/$yt);

		$topx=toppart($x,$i,3);
		while($q[$m] * $top > $topx)
			$q[$m]--;

		$y2=array_slice($y2,1);
		$x2=bsub($x,bmul([$q[$m]],$y2));

		if(count($x2)==0){
			$q[$m]--;
			$x2=bsub($x,bmul([$q[$m]],$y2));
		}
		$x=$x2;
	}

	if($shift){
		for($i=0; $i<count($x)-1; $i++)
			$x[$i]=($x[$i] >> $shift) | (($x[$i+1] << $shift2) & $bm);
		$x[count($x)-1] >>= $shift;
	}

	while(count($q) > 1 && $q[count($q)-1]==0)
		$q=array_slice($q, 0, count($q)-1);
	while(count($x) > 1 && $x[count($x)-1]==0)
		$x=array_slice($x, 0, count($x)-1);

	return ['q'=>$q, 'mod'=>$x];
}
```

So as I marked in the PHP code I have a problem with the **array_push($x,$x)**, seems like this is not the equivalent of **x=x.concat()**.
Array_push add the whole current $x values as a new element to the existing **$x** array:

> $x=[ 1, 2, 3 ];<br>
> array_push($x,$x);<br>
> then $x will be [ 1, 2, 3, [ 1, 2, 3 ] ]

If I try to flatten the array (**$x=array_merge(...$x);**) then a new PHP error shows up: _array_merge(): Argument #1 is not an array_

I would really appreciate it if anyone have any idea, how to convert properly this JS function to a PHP version. 
Thanks in advance.