ignore_user_abort
Array pack:
<?php
function pack_array($v,$a) {
return call_user_func_array(pack,array_merge(array($v),(array)$a));
}
?>
pack
(PHP 4, PHP 5)
pack — Empaquetar datos en una cadena binaria
Descripción
Empaquetar los argumentas dados en una cadena binaria de acuerdo a formato .
La idea de esta función fue tomada de Perl y todos los códigos de formato funcionan igual que en aquél lenguaje, sin embargo, existen algunos códigos de formato faltantes, como el código "u" de Perl.
Note que la distinción entre valores con signo y sin signo sólo afecta a la función unpack(), mientras que la función pack() entrega el mismo resultado para códigos de formato con signo y sin signo.
También note que PHP almacena valores integer internamente como valores con signo de un tamaño dependiente de la máquina. Si le entrega un valor entero sin signo demasiado largo para ser almacenado en esa forma, es convertido a un valor float, lo cual frecuentemente produce un resultado inesperado.
Lista de parámetros
- formato
-
La cadena formato consiste de códigos de formato seguidos por un argumento opcional de repetición. El argumento de repetición puede ser un valor entero o * para la repetición hasta el final de los datos de entrada. En el caso de a, A, h, y H el conteo de repetición especifica cuántos caracteres de un argumento de datos son tomados, para @ es la posición absoluta en dónde colocar el siguiente dato, para todos los demás el conteo de repetición especifica cuántos argumentos de datos son consumidos y empaquetados en la cadena binaria resultante.
Actualmente los formatos implementados son:
Caracteres de formato de pack() Código Descripción a cadena completada con caracteres NUL A cadena completada con espacios h cadena Hex, nibble bajo primero H cadena Hex, nibble alto primero c caracter con signo C caracter sin signo s short con signo (siempre de 16 bits, orden de bytes de máquina) S short sin signo (siempre de 16 bits, orden de bytes de máquina) n short sin signo (siempre de 16 bits, byte más significativo primero) v short sin signo (siempre de 16 bits, byte menos significativo primero) i entero con signo (tamaño y orden de bytes dependiente de la máquina) I entero sin signo (tamaño y orden de bytes dependiente de la máquina) l long con signo (siempre de 32 bits, orden de bytes de máquina) L long sin signo (siempre de 32 bits, orden de bytes de máquina) N long sin signo (siempre de 32 bits, byte más significativo primero) V long sin signo (siempre de 32 bits, byte menos significativo primero) f flotante (tamaño y representación dependiente de la máquina) d doble (tamaño y representación dependiente de la máquina) x byte NUL X Copiar un byte @ relleno de NUL hasta una posición absoluta - args
-
Valores retornados
Devuelve la cadena binaria que contiene los datos.
Ejemplos
Example #1 Ejemplo de pack()
<?php
$datos_binarios = pack("nvc*", 0x1234, 0x5678, 65, 66);
?>
La cadena binaria resultante tendrá 6 bytes de longitud y contendrá la secuencia de bytes 0x12, 0x34, 0x78, 0x56, 0x41, 0x42.
add a note
User Contributed Notespack
Anonymous
06-Jul-2008 01:17
06-Jul-2008 01:17
php at nagler-ihlein dot de
08-May-2008 04:26
08-May-2008 04:26
Be aware of format code H always padding the 0 for byte-alignment to the right (for odd count of nibbles).
So pack("H", "7") results in 0x70 (ASCII character 'p') and not in 0x07 (BELL character)
as well as pack("H*", "347") results in 0x34 ('4') and 0x70 ('p') and not 0x03 and 0x47.
Quis AT spam.to.my.devnull.quis.cx
25-Jan-2008 03:45
25-Jan-2008 03:45
<?PHP
function ntohs($port) {
$b=pack("N", $port);
return substr($b,2,2);
}
?>
I've spent a number of hours (n>=2) finding how to do this,
it works like the c function 'ntohs', used for eg the socks5 proxy protocol.
dylan at pow7 dot com
06-Sep-2007 01:00
06-Sep-2007 01:00
This is how I used pack to convert base2 to base64 since base_convert doesn't support base64
The base conversions don't work for long strings, which is why I convert 1 byte at a time
Hope this helps someone
function base2to64($base2) {
if ($remainbits = strlen($base2)%8) $base2 .= str_repeat('0',8-$remainbits);
$base64 = NULL;
for ($i=0;$i<strlen($base2);$i+=8) $base16 .= sprintf('%02x',bindec(sprintf('%08d',substr($base2,$i,8))));
return base64_encode(pack('H*',$base16));
}
function base64to2($base64) {
list($base16) = unpack('H*0',base64_decode($base64));
$base2 = NULL;
for ($i=0;$i<strlen($base16);$i++) $base2 .= sprintf('%04d',base_convert(substr($base16,$i,1),16,2));
return $base2;
}
Chr dot Eichert<moga at mx dot homelinux dot org>
16-Feb-2007 01:21
16-Feb-2007 01:21
This is how you can produce a code that is in fact a picture.
(This code is a complete tool, copy it to a file, call it 'somehow.php' and produce your pictures as hexcode).
<!--// ***Begin of File*** //-->
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>" enctype="multipart/form-data">
<input type="file" name="thefile"><input type="submit">
</form>
<?php
$rh = fopen ($_FILES['thefile']['tmp_name'], "r");
$pb = fread($rh, 8192);
fclose($rh);
$pc = bin2hex($pb);
$pd = wordwrap($pc, 76, "\".<br /> \n \"", 1);
echo "<TT>\$hexpic=\""."$pd"."\"\n</TT>;";
?>
<!--// ***End of File*** //-->
Copy the result in your site code somewhere. For to show the code as a picture you can use something like what dirk (at) camindo de wrote ...
<?php
$hexpic=".......................
.....................";
$data = pack("H" . strlen($hexpic), $hexpic);
header("Content-Type: image/png");
// maybe your is jpeg / gif / png
header("Last-Modified: " . date("r", filectime($_SERVER['SCRIPT_FILENAME'])));
header("Content-Length: " . strlen($data));
echo $data;
?>
have fun!
dirk (at) camindo de
19-Jan-2007 12:22
19-Jan-2007 12:22
Work around newsletter tracking:
include a transparent gif (1x1 pixel) with url = track.php and parameters.
track.php has to write the parameters e.g. into a database and provides the gif - using following code:
header("Content-Type: image/gif");
header("Content-Length: 49");
echo pack('H*',
'47494638396101000100910000000000ffffffff'
.'ffff00000021f90405140002002c000000000100'
.'01000002025401003b'
);
Newdawn.dk
23-Mar-2006 01:25
23-Mar-2006 01:25
When trying to create a ZIP file using the pack function - I experienced trouble with the "a" code - It converted all chars correct from the std. ASCII charset but not more language specific like ÆøÅ.
It seems that ZIP files do not use the same HEX for these as everything else does.
The fix was a quick workaround but you'll probably get the picture:
function UniHex($str) {
// æ ø å Æ Ø Å
//These are simply one HEX code being replaced by another to correct the issue
$except = array("E6"=>"91","F8"=>"9B","E5"=>"86","C6"=>"92","D8"=>"9D", "C5"=>"8F");
for($i = 0; $i < strlen($str); $i++) {
$hex = bin2hex(substr($str, $i, 1));
if ($except[strtoupper($hex)])
$hex = $except[strtoupper($hex)];
$return .= $hex;
}
return $return;
}
And then i replaced an "a100" code with "H".strlen(uniHex($mystring))
This is like i said a quick workaround, but if you find the real reason for this i'd be happy to see it
j.s.hoekstra
13-Mar-2006 05:57
13-Mar-2006 05:57
/* Convert float from HostOrder to Network Order */
function FToN( $val )
{
$a = unpack("I",pack( "f",$val ));
return pack("N",$a[1] );
}
/* Convert float from Network Order to HostOrder */
function NToF($val )
{
$a = unpack("N",$val);
$b = unpack("f",pack( "I",$a[1]));
return $b[1];
}
Patrik Fimml
11-Oct-2005 07:42
11-Oct-2005 07:42
You will get the same effect with
<?php
function _readInt($fp)
{
return unpack('V', fread($fp, 4));
}
?>
or unpack('N', ...) for big-endianness.
19-Feb-2005 08:09
I needed to convert binary values from a file to integers.
Maybe there is something simpler, but the snippets i saw above seemed a little convoluted:
function bin2asc ($binary)
{
$val = 0;
for ($i = strlen($binary) - 1; $i >= 0; $i--) {
$ch = substr($binary, $i, 1);
$val = ($val << 8) | ord($ch);
}
return $val;
}
This was called like the following from a binary file:
function _readInt($fp)
{
return bin2asc(fread($fp, 4));
}
Note that the for loop should be reversed for network byte order instead of intel byte order. Also the conversion will work with any number of bytes, but will happily overflow.
zilinex at yahoo dot com
02-Sep-2004 08:12
02-Sep-2004 08:12
a cool function to converrt numbers to Persian numbers(utf-8)
origin: http://www.farsiweb.info/jalali/jalali.phps
function farsinum($str)
{
$ret = "";
for ($i = 0; $i < strlen($str); ++$i) {
$c = $str[$i];
if( $c >= '0' && $c <= '9' )
$out .= pack("C*", 0xDB, 0xB0 + $c);
else
$ret .= $c;
}
return $ret;
}
Jurgen Braam
02-Oct-2003 08:39
02-Oct-2003 08:39
take note: if you produce binary files using PHP on multiple platforms, that you use one of the machine-independent pack options.
This means 's' 'S' 'i' 'I' 'd' and 'f' are _EVIL_ :) Took me some time to figure out what my Excel-generator what futzing about :) Turned out the production machine was a Sun Sparc. I develop on my own x86 Linux server.
Hope this helps anyone...
c-ya,
Jurgen
mfisch[at]kaz[dot]com
10-Jul-2001 06:53
10-Jul-2001 06:53
If you are trying to do ascii <--> binary conversions like me;
you probably found that unlike the perl pack functions, these wont help too much. Attached are two functions I wrote to accomplish this task.
<br>
function bin2asc ($binary)
{
$i = 0;
while ( strlen($binary) > 3 )
{
$byte[$i] = substr($binary, 0, 8);
$byte[$i] = base_convert($byte[$i], 2, 10);
$byte[$i] = chr($byte[$i]);
$binary = substr($binary, 8);
$ascii = "$ascii$byte[$i]";
}
return $ascii;
}
<br>
function asc2bin ($ascii)
{
while ( strlen($ascii) > 0 )
{
$byte = ""; $i = 0;
$byte = substr($ascii, 0, 1);
while ( $byte != chr($i) ) { $i++; }
$byte = base_convert($i, 10, 2);
$byte = str_repeat("0", (8 - strlen($byte)) ) . $byte; # This is an endian (architexture) specific line, you may need to alter it.
$ascii = substr($ascii, 1);
$binary = "$binary$byte";
}
return $binary;
}
<br>
Im not sure these are the most efficient functions, but surely alot faster than loading up a perl interpreter for every binary conversion =)
plutus at gmx dot de
10-Aug-2000 01:14
10-Aug-2000 01:14
Note that the the upper command in perl looks like this:<br>
$binarydata = pack ("n v c*", 0x1234, 0x5678, 65, 66);<br>
In PHP it seems that no whitespaces are allowed in the first parameter. So if you want to convert your pack command from perl -> PHP, don't forget to remove the whitespaces!