A brief introduction to PHP's method of converting bytes into KB, MB, GB, and TB

<?php
function getFilesize($num){
   $p = 0;
   $format=&#39;bytes&#39;;
   if($num>0 && $num<1024){
     $p = 0;
     return number_format($num).&#39; &#39;.$format;
   }
   if($num>=1024 && $num<pow(1024, 2)){
     $p = 1;
     $format = &#39;KB&#39;;
  }
  if ($num>=pow(1024, 2) && $num<pow(1024, 3)) {
    $p = 2;
    $format = &#39;MB&#39;;
  }
  if ($num>=pow(1024, 3) && $num<pow(1024, 4)) {
    $p = 3;
    $format = &#39;GB&#39;;
  }
  if ($num>=pow(1024, 4) && $num<pow(1024, 5)) {
    $p = 3;
    $format = &#39;TB&#39;;
  }
  $num /= pow(1024, $p);
  return number_format($num, 3).&#39; &#39;.$format;
}
echo "来自脚本之家www.jb51.net的测试结果：<br/>";
echo getFilesize(200)."<br/>";
echo getFilesize(20000)."<br/>";
echo getFilesize(2000000)."<br/>";
echo getFilesize(200000000)."<br/>";
echo getFilesize(20000000000)."<br/>";
echo getFilesize(2000000000000)."<br/>";
?>