Calculates the minimum and the maximum safe integer values which can vary depending on the environment where the code is run. This can be used to have constants similar to JavaScript's Number.MIN_SAFE_INTEGER and Number.MAX_SAFE_INTEGER.

MIN_SAFE_INTEGER-MAX_SAFE_INTEGER.inc.php

<?php
// Similar to JavaScript's Number.MAX_SAFE_INTEGER
define("MAX_SAFE_INTEGER", (function() {
  for ($e = 1; pow(2, $e) - ($MAX_SAFE_INTEGER = (pow(2, $e - 1) - 1) * 2 + 1) == 1; $e++) {
    if ($e > 999) {
      throw new Exception("Maximum integer couldn't be found.");
    }
  }
  return $MAX_SAFE_INTEGER;
})());

// Similar to JavaScript's Number.MIN_SAFE_INTEGER
define("MIN_SAFE_INTEGER", -MAX_SAFE_INTEGER - 1);