Loop function until there is no specified needle in the haystack - php

Question

I'm trying to build a function, that will check if the needle is in haystack, if it is then the function should loop until there is none.
So far I've built a function for random number generation. What that function does is it will create a random string then hash it with sha512. The function then extracts all the numbers from a string and multiplies it by 2.
It leaves me with a long line of numbers, then I'll use mt_rand to specify start and end point for strpos. After that I just return the number that was created randomly.
function randomNumber($suurus, $max){
mb_internal_encoding("UTF-8");
$possible="aábcdeéfghiíjklmnoóöópqrstuúüűvwxyzAÁBCDEÉFGHIÍJKLMNOÓÖŐPQRSTUÚVWXYZ";
$char = mb_substr($possible,rand(0, mb_strlen($possible) - 1),1);
$str = openssl_digest($char, 'sha512');
$str = preg_replace('/[^1-9.]+/', '', $str);
$str = $str*2;
$strLen = strlen($str)-5;
$strStart = mt_rand(1, $strLen);
$strEnd = mt_rand(1, $suurus);
$str = substr($str, $strStart, $strEnd);
while($str > $max){
$str = $str / 2;
}
return round($str);
The thing is that this number can't repeat, I need it to be unique at all times for my app.
I actually accomplished what I wanted with if else statements, but that means I have to write a long script of repeated if statements until I get the results I want. I really don't think this is the smartest way to do things.
if(!isset($voitjad)){
$voitjad[$vCounter][] = array(
'nimi' => $voitja,
'auhind' => $keyCode['v'.$vCount.''],
'rn' => $rN,
'siin' => 1,
'id' => $voitjaID
);
}else{
if(!exist($rN, $voitjad)){
$voitjad[$vCounter][] = array(
'nimi' => $voitja,
'auhind' => $keyCode['v'.$vCount.''],
'rn' => $rN,
'siin' => 1,
'id' => $voitjaID
);
}else{
$rN = randomNumber($atLength, $atCount);
$voitja = $attendcheckfb['attending'][$rN]['name'];
$voitjaID = $attendcheckfb['attending'][$rN]['id'];
if(!exist($rN, $voitjad)){
$voitjad[$vCounter][] = array(
'nimi' => $voitja,
'auhind' => $keyCode['v'.$vCount.''],
'rn' => $rN,
'siin' => 2,
'id' => $voitjaID
);
}else{ and so on....
I also tried with do-while loop, but I couldn't really get it working, I'm not sure what exactly I'm doing wrong here. If you can educate me, shoot me with information.
$nimed = array_values($nimed);
$voitja = $nimed[$rN]['name'];
$voitjaID = $nimed[$rN]['id'];
$voitjad[$vCounter][] = array(
'nimi' => $voitja,
'auhind' => $keyCode['v'.$vCount.''],
'rn' => $rN,
'siin' => 1,
'id' => $voitjaID
);
$oitjaCount++;
$rN = randomNumber($nimedLength, $nimedCount);
} while(!exist($rN, $voitjad));
If there's a way for me to get better randomly generated numbers, then please tell me, I'm open for suggestions. Meanwhile I need help with this needle, haystack thing.

Answer 1

You can either do it with a loop:
function get_unique_hashcode() {
global $hash_array;
do {
$hashcode = make_random_hashcode();
} while (in_array($hashcode, $hash_array));
$hash_array[] = $hashcode;
return $hashcode;
}
Or you can do it with recursion:
function get_unique_hashcode() {
global $hash_array;
$hashcode = make_random_hashcode();
if (in_array($hashcode, $hash_array)) {
return get_unique_hashcode();
} else {
$hash_array[] = $hashcode;
return $hashcode;
}
}
This is just a general structure, you may need to adjust it for your detailed needs.