Custom implementation of PHP strpos function

strpos.php

<?php

# Live Codding https://codeshare.io/

# Task
Find the position of the first occurrence of a substring in a string
strpos ( string $haystack , string $needle [, int $offset = 0 ] ) : int | false


fucntion strpos(string $haystack, string $needle, int $offset = 0): int|false 
{    
}

# ----

# Solution
function strPosition($haystack, $needle, $offset = 0)
{
    $count = strLength($needle);
    $countHaystack = strLength($haystack);
  
    if ($offset < 0) {
        return false;
    }
    
    $start = false;
    for ($i = 0; $i < $count; $i++) {
        $innerCount = 0;
        for ($o = $offset; $o < $countHaystack; $o++) {
            $symbol = $needle[$i];
            $hSymbol = $haystack[$o];
            if ($symbol === $hSymbol) {
                $i++;
                $start = $o;
                $innerCount++;
                if ($innerCount === $count) {
                    break 2;
                }
            } else {
                $start = false;
            }
        }
    }
    
    if ($start !== false) {
        $start = $start - ($count - 1);
    }

    return $start;
}

function strLength($string)
{
    $i = 0;
    while (true) {
        if (isset($string[$i])) {
            $i++;
        } else {
            break;
        }
    }

    return $i;
}

var_dump(strPosition('/api/controller/action/api', 'api', 0));
var_dump(strpos('/api/controller/action/api', 'api', 0));