How can I get a hex dump of a string in PHP?
I'm investigating encodings in PHP5. Is there some way to get a raw hex dump of a string? i.e. a hex representation of each of the bytes (not characters) in a string?
Solution 1:
echo bin2hex($string);
or:
for ($i = 0; $i < strlen($string); $i++) {
echo str_pad(dechex(ord($string[$i])), 2, '0', STR_PAD_LEFT);
}
$string is the variable which contains input.
Solution 2:
For debugging work with binary protocols, I needed a more traditional HEX dump, so I wrote this function:
function hex_dump($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 += $width;
}
}
This produces a more traditional HEX dump, like this:
hex_dump($data);
=>
0 : 05 07 00 00 00 64 65 66 61 75 6c 74 40 00 00 00 [.....default@...]
10 : 31 42 38 43 39 44 30 34 46 34 33 36 31 33 38 33 [1B8C9D04F4361383]
20 : 46 34 36 32 32 46 33 39 32 46 44 38 43 33 42 30 [F4622F392FD8C3B0]
30 : 45 34 34 43 36 34 30 33 36 33 35 37 45 35 33 39 [E44C64036357E539]
40 : 43 43 38 44 35 31 34 42 44 36 39 39 46 30 31 34 [CC8D514BD699F014]
Note that non-visible characters are replaced with a period - you can change the number of bytes per line ($width) and padding character ($pad) to suit your needs. I included a $newline argument, so you can pass "<br/>" if you need to display the output in a browser.
Solution 3:
It's years later, but in case others are searching for this too, I took the liberty to modify mindplay.dk's code to make it accept various options and simulate the output of the BSD command hexdump -C file:
/**
* Dumps a string into a traditional hex dump for programmers,
* in a format similar to the output of the BSD command hexdump -C file.
* The default result is a string.
* Supported options:
* <pre>
* line_sep - line seperator char, default = "\n"
* bytes_per_line - default = 16
* pad_char - character to replace non-readble characters with, default = '.'
* </pre>
*
* @param string $string
* @param array $options
* @param string|array
*/
function hex_dump($string, array $options = null) {
if (!is_scalar($string)) {
throw new InvalidArgumentException('$string argument must be a string');
}
if (!is_array($options)) {
$options = array();
}
$line_sep = isset($options['line_sep']) ? $options['line_sep'] : "\n";
$bytes_per_line = @$options['bytes_per_line'] ? $options['bytes_per_line'] : 16;
$pad_char = isset($options['pad_char']) ? $options['pad_char'] : '.'; # padding for non-readable characters
$text_lines = str_split($string, $bytes_per_line);
$hex_lines = str_split(bin2hex($string), $bytes_per_line * 2);
$offset = 0;
$output = array();
$bytes_per_line_div_2 = (int)($bytes_per_line / 2);
foreach ($hex_lines as $i => $hex_line) {
$text_line = $text_lines[$i];
$output []=
sprintf('%08X',$offset) . ' ' .
str_pad(
strlen($text_line) > $bytes_per_line_div_2
?
implode(' ', str_split(substr($hex_line,0,$bytes_per_line),2)) . ' ' .
implode(' ', str_split(substr($hex_line,$bytes_per_line),2))
:
implode(' ', str_split($hex_line,2))
, $bytes_per_line * 3) .
' |' . preg_replace('/[^\x20-\x7E]/', $pad_char, $text_line) . '|';
$offset += $bytes_per_line;
}
$output []= sprintf('%08X', strlen($string));
return @$options['want_array'] ? $output : join($line_sep, $output) . $line_sep;
}
and this is a hex dump of a small file:
00000000 89 50 4e 47 0d 0a 1a 0a 00 00 00 0d 49 48 44 52 |.PNG........IHDR|
00000010 00 00 00 10 00 00 00 10 02 03 00 00 00 62 9d 17 |.............b..|
00000020 f2 00 00 00 09 50 4c 54 45 04 04 04 99 99 cc d7 |.....PLTE.......|
00000030 d7 d7 2a 66 f6 6b 00 00 00 38 49 44 41 54 78 9c |..*f.k...8IDATx.|
00000040 63 08 05 02 06 24 22 0b 44 24 01 89 ac a4 69 4b |c....$".D$....iK|
00000050 19 1a 16 68 70 31 74 29 75 2c 42 22 1a 16 75 00 |...hp1t)u,B"..u.|
00000060 c5 22 33 96 32 74 86 46 4c 65 58 19 1a 35 15 61 |."3.2t.FLeX..5.a|
00000070 00 00 df be 19 a6 2e 62 80 87 00 00 00 00 49 45 |.......b......IE|
00000080 4e 44 ae 42 60 82 |ND.B`.|
00000086
and this is the phpunit test:
<?php
if (isset($argv)) {
print "Running outside of phpunit. Consider using phpunit.\n";
class PHPUnit_Framework_TestCase {}
}
class Test extends PHPUnit_Framework_TestCase
{
const FUNCTION_NAME = 'hex_dump';
const DATA_BASE64 = '
iVBORw0KGgoAAAANSUhEUgAAABAAAAAQAgMAAABinRfyAAAACVBMVEUEBASZmczX19cqZvZrAAAA
OElEQVR4nGMIBQIGJCILRCQBiaykaUsZGhZocDF0KXUsQiIaFnUAxSIzljJ0hkZMZVgZGjUVYQAA
374Zpi5igIcAAAAASUVORK5CYII=';
private $expect = array(
'00000000 89 50 4e 47 0d 0a 1a 0a 00 00 00 0d 49 48 44 52 |.PNG........IHDR|',
'00000010 00 00 00 10 00 00 00 10 02 03 00 00 00 62 9d 17 |.............b..|',
'00000020 f2 00 00 00 09 50 4c 54 45 04 04 04 99 99 cc d7 |.....PLTE.......|',
'00000030 d7 d7 2a 66 f6 6b 00 00 00 38 49 44 41 54 78 9c |..*f.k...8IDATx.|',
'00000040 63 08 05 02 06 24 22 0b 44 24 01 89 ac a4 69 4b |c....$".D$....iK|',
'00000050 19 1a 16 68 70 31 74 29 75 2c 42 22 1a 16 75 00 |...hp1t)u,B"..u.|',
'00000060 c5 22 33 96 32 74 86 46 4c 65 58 19 1a 35 15 61 |."3.2t.FLeX..5.a|',
'00000070 00 00 df be 19 a6 2e 62 80 87 00 00 00 00 49 45 |.......b......IE|',
'00000080 4e 44 ae 42 60 82 |ND.B`.|',
'00000086',
);
public function testRequire() {
$file = __DIR__ . '/' . static::FUNCTION_NAME . '.php';
$this->assertFileExists($file);
include($file);
$this->assertTrue(function_exists(static::FUNCTION_NAME));
}
public function testString() {
$func = static::FUNCTION_NAME;
$data = base64_decode(static::DATA_BASE64);
if (!is_string($data)) {
throw new Exception('Unable to decode base64 encoded test data');
}
$dump = $func($data);
//var_export($dump);
$this->assertTrue(is_string($dump));
$this->assertEquals($dump, join("\n", $this->expect) . "\n");
}
}
if (isset($argv)) {
$func = Test::FUNCTION_NAME;
require_once($func . '.php');
if (count($argv) < 2) {
print "Pass arguments file, from, length.\n";
}
else {
$file = $argv[1];
if (!file_exists($file)) {
die("File not found: $file\n");
}
$from = isset($argv[2]) && preg_match('/^\d{1,9}$/', $argv[2]) ? intval($argv[2]) : null;
$len = isset($argv[3]) && preg_match('/^\d{1,9}$/', $argv[3]) ? intval($argv[3]) : filesize($file);
$h = fopen($file, 'r');
if ($from) {
fseek($h, $from);
}
$data = fread($h, $len);
fclose($h);
$dump = hex_dump($data);
print $dump;
//$dump = hex_dump($data, array('want_array' => true));
//print_r($dump);
}
}
Solution 4:
While debugging a binary protocol I needed a hexdump() too. I decided to publish my solution as a PEAR package as it's definitely useful. You can also browse the code at github.
PEAR : http://www.metashock.de/pear
GitHub : http://www.github.com/metashock/Hexdump
In addition to mindplays solution it supports propper rendering of the last line and additional params. Also the package contains a php executable named phphd for hexdumps on cmdline. This might be helpful on Windows Systems :)
@mindplay.dk : Thanks for the strtr() idea. It appeared slight faster than my former attempt. Integrated that into my version. (Using a decreased translation buffer)..