php 打印出字符串的16进制

<?php
/*
php 打印出字符串的16进制数据
*/
function hex_dump($data, $newline="n")
{
  static $from = '';
  static $to = '';
 
  static $width = 16; # number of bytes per line
 
  static $pad = '.'; # padding for non-visible characters
 
  if ($from==='')
  {
    for ($i=0; $i<=0xFF; $i++)
    {
      $from .= chr($i);
      $to .= ($i >= 0x20 && $i <= 0x7E) ? chr($i) : $pad;
    }
  }
 
  $hex = str_split(bin2hex($data), $width*2);
  $chars = str_split(strtr($data, $from, $to), $width);
 
  $offset = 0;
  foreach ($hex as $i => $line)
  {
    echo sprintf('%6X',$offset).' : '.implode(' ', str_split($line,2)) . ' [' . $chars[$i] . ']' . $newline;
    $offset += $width;
  }
}
 
$info="this is a testx00x99hex_dump";
print_r(hex_dump($info));
/*
输出结果：
 
0 : 74 68 69 73 20 69 73 20 61 20 74 65 73 74 00 99 [this is a test..]
 
10 : 68 65 78 5f 64 75 6d 70 [hex_dump]
*/
?>