note 104202 added to function.crc32
| From: | Reikaze at osu1 dot php dot net | Date: | Tue, 31 May 2011 18:39:18 +0000 |
| Subject: | note 104202 added to function.crc32 | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-180141@lists.php.net to get a copy of this message | ||
I would like to expand a little bit of information about the code "lenar at city dot ee
27-Oct-2008 08:25" mentioned.
About:
Optimized CRC16-CCITT (0xFFFF) Code.
It doesn't returns a hex expressed CRC16-CCITT, instead, returns a decimal integrer.
The result to be used, as part of a string to be sended to any device/application that would
interpretate it as HEX code (e.g. part of a device protocol), first you'll need to base convert
it to hex, and code it as binary hex data.
function INTtorawHEX ( $integrer ) {
$hex = base_convert($integrer, 10, 16);
$rawhex = pack("H*", $hex);
return $rawhex;}
function crc16($data)
{
$crc = 0xFFFF;
for ($i = 0; $i < strlen($data); $i++)
{
$x = (($crc >> 8) ^ ord($data[$i])) & 0xFF;
$x ^= $x >> 4;
$crc = (($crc << 8) ^ ($x << 12) ^ ($x << 5) ^ $x) & 0xFFFF;
}
$crc = INTtorawHEX($crc);
return $crc;
}
----
Server IP: 69.147.83.197
Probable Submitter: 189.248.168.217
----
Manual Page -- http://www.php.net/manual/en/function.crc32.php
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