PHP functions for calculating prime numbers.

calcprime.php

<?php

/**
* 	Check to see if a given integer is prime.
*
* 	Adapted from this Python implementation http://pthree.org/2007/09/05/prime-numbersin-	 python/
*   This list of the first 10,000 prime numbers is also helpful http://primes.utm.edu/lists/small/10000.txt
*
*	 @param int $number the number to check to see if it is prime.
*	 @return boolean true if the number is prime, false if not.
*/
function isPrime($number) 
{
    $n = abs($number);
    $i = 2;
    while ($i <= sqrt($n))
    {
        if ($n % $i == 0) {
            return false;
        }
        $i++;
    }
    return true;
}

/**
* 	Given a positive integer, find the next 10 prime numbers that are equal to it or greater.
*
*	 @param int $number the number to find the next time prime numbers.
*	 @return array an array of the next ten prime numbers.
*/
function nextPrimes($number) {
    $nextP = array();
    //Keep looping until we have an array of 10 prime numbers.
    while ((sizeof($nextP) <= 9) and ($number <= 100000))
    {
        if (isPrime($number) == true) {
            $nextP[] = $number;
        }
        $number++;
    }
    return $nextP;
}

/**
* 	Given a value, returns true if the value is an integer and within the provided range - 1 to 100,000. 
*	Adapted from dave dot marr's contribution in the PHP docs - http://php.net/manual/en/function.is-numeric.php
*
*	 @param string $val the raw value submitted
*	 @return boolean true if the value is a positive integer, false if note. 
*/
function checkInRange($val) {
  //remove any commas that user may have provided
  $val = str_replace(',', '', $val); 
  if (is_numeric($val)) { 
    if (is_int($val + 0)) {
    	if (($val > 0) && ($val <= 100000)) {
        	return true;
        } else {
        	return false;
        }
    } 
  } 
  return false; 
}
?>