bit handling function

[inexion]

hello,

can anyone help me out with a bit handler?

it seems as if php's decbin() removes leading zeroes when converting
from hex....so for example decbin(hexdec()); basically removes any
leading zeroes.

i'm trying to convert some 32bit hex words into bin, and the first 12
bits need to be broken down into 3-bit sets for decoding a key of
sorts. for example:

(on paper)
0x2101769:
-------normal bin------- ----3-bit sets----
0010 0001 0000 0001 011 101 101 001

(in php)
decbin(hexdec(2101769)) = 1000000001001000001001
are there any functions that could break apart the number once i get
the conversion done correctly?
thanks!

[Michael Fesser]

..oO(inexion)

>can anyone help me out with a bit handler?

it seems as if php's decbin() removes leading zeroes when converting
from hex....so for example decbin(hexdec()); basically removes any
leading zeroes.

Correct, because in a number leading zeros don't have any meaning:
1 = 01 = 001 ...

>i'm trying to convert some 32bit hex words into bin, and the first 12
bits need to be broken down into 3-bit sets for decoding a key of
sorts. for example:

(on paper)
0x2101769:
-------normal bin------- ----3-bit sets----
0010 0001 0000 0001 011 101 101 001

(in php)
decbin(hexdec(2101769)) = 1000000001001000001001
are there any functions that could break apart the number once i get
the conversion done correctly?
thanks!

Pad the string with zeros to the required length of at least 12 chars,
take the last 12 chars from it and split them into groups of three:

<?php
$hexCode = '2101769';
$binCode = substr(sprintf('%012b', hexdec($hexCode)), -12);
$parts = str_split($binCode, 3);
var_dump($parts);
?>

HTH
Micha

[axlq]

In article <80**********************************@e39g2000hsf. googlegroups.com>,
inexion <ab******@gmail.comwrote:

>it seems as if php's decbin() removes leading zeroes when converting
from hex....so for example decbin(hexdec()); basically removes any
leading zeroes.

If you want leading zeros in a 32-bit binary representation, try
$binary = sprintf('%032b', $number);

>i'm trying to convert some 32bit hex words into bin, and the first
12 bits need to be broken down into 3-bit sets for decoding a key

Lowest 3 bits:
$low3 = sprintf('%03b', $number & 0x0003);

Next 3 bits:
$next3 = sprintf('%03b', ($number >3) & 0x0003);

Next 3 bits:
$another3 = sprintf('$03b', ($number >6) & 0x0003);

....and so on.

-A

[inexion]

Thanks for the replies guys -
i got it working with this code:

$tnum = array();
$tnum[] = hexdec($targets['flags'][$i]);
$binCode = substr(sprintf('%012b', $tnum[$i]), -12);
$parts = str_split($binCode, 3);
echo "flags: ".$parts[0]." ".$parts[1]." ".$parts[2]." ".
$parts[3]."<br />";

thanks!!

[inexion]

Thanks for the replies guys -
i got it working with this code:

$tnum = array();
$tnum[] = hexdec($targets['flags'][$i]);
$binCode = substr(sprintf('%012b', $tnum[$i]), -12);
$parts = str_split($binCode, 3);
echo "flags: ".$parts[0]." ".$parts[1]." ".$parts[2]." ".
$parts[3]."<br />";

thanks!!

[inexion]

Thanks for the replies guys -
i got it working with this code:

$tnum = array();
$tnum[] = hexdec($targets['flags'][$i]);
$binCode = substr(sprintf('%012b', $tnum[$i]), -12);
$parts = str_split($binCode, 3);
echo "flags: ".$parts[0]." ".$parts[1]." ".$parts[2]." ".
$parts[3]."<br />";

thanks!!

[Michael Fesser]

..oO(inexion)

>Thanks for the replies guys -
i got it working with this code:

$tnum = array();
$tnum[] = hexdec($targets['flags'][$i]);
$binCode = substr(sprintf('%012b', $tnum[$i]), -12);
$parts = str_split($binCode, 3);
echo "flags: ".$parts[0]." ".$parts[1]." ".$parts[2]." ".
$parts[3]."<br />";

I would write the last line as

echo "flags: {$parts[0]} {$parts[1]} {$parts[2]} {$parts[3]}<br />";

But that's just personal preference.

>thanks!!

You're welcome.

Micha