Generate Unique Numeric ID in PHP

generate_unique_numeric.php

/**
 * Generate Unique Numeric ID in PHP
 * Note: 
 * - In 32bit, if set $abs to true will make lengths of digits fixed to 10, but will reduce the level of uniqueness
 * - In 32bit, if set $abs to false sometimes will return 11 digits because of negative number.
 * - This is based of function uniqid() which uniqueness is still not guaranteed as mentioned in http://php.net/manual/en/function.uniqid.php
 *  
 * @param prefix = adding additional value on the first to get more uniqueness level.
 * @param suffix = adding additional value on the last to get more uniqueness level.
 * @param fixedkey = adding additional value on uniqid string before converted to numeric
 * @param abs = Will make sure all return value is positive and fixed length 10 (without any prefix or suffix). Default is true.
 *
 * @return string
 */
function uniqidNumeric($prefix,$suffix,$fixedkey,$abs=true){
  $data = (($abs)?abs(crc32(uniqid($fixedkey))):crc32(uniqid($fixedkey)));
  $pad = (10 - strlen($data));
  if($pad > 0){
    $leading = "";
    for ($i=1;$i<=$pad;$i++){
      $leading .= '0';
    }
    return $prefix.str_replace('-','00',str_pad($data, 10, $leading, STR_PAD_LEFT)).$suffix;
  }
  return $prefix.str_replace('-','0',$data).$suffix;
}
                               
// Test loop 100 times uniqid numeric in a single thread
echo '<br> Generate only numeric<br>';
for ($i=1;$i<=100;$i++){
 echo $i.' : '.uniqidNumeric().'<br>';  
}echo '<br>';


echo '<br> Generate with prefix<br>';
for ($i=1;$i<=100;$i++){
 echo $i.' : '.uniqidNumeric('PREFIX').'<br>';  
}echo '<br>';


echo '<br> Generate with prefix and suffix<br>';
for ($i=1;$i<=100;$i++){
 echo $i.' : '.uniqidNumeric('PREFIX','SUFFIX').'<br>';  
}echo '<br>';
                         

echo '<br> Generate with prefix, suffix and fixed key<br>';
for ($i=1;$i<=100;$i++){
 echo $i.' : '.uniqidNumeric('PREFIX','SUFFIX','yourfixedkey').'<br>';  
}echo '<br>';


echo '<br> Generate with prefix, suffix, fixed key, non abs<br>';
for ($i=1;$i<=100;$i++){
 echo $i.' : '.uniqidNumeric('PREFIX','SUFFIX','yourfixedkey',false).'<br>';  
}echo '<br>';