At the moment I haven’t got the time to update my utilities to support CRC64. However, it is pretty straightforward if you’ve read http://stigge.org/martin/pub/SAR-PR-2006-05.pdf .

I have tried the reverse crc code and it works perfectly, that is: to get the four bytes when I input only four bytes for the CRC32 checksum generation. I now have C# CRC64 generation code with me. I would like to know if I can reverse CRC64 checksum to get four-8 bytes back. If there’s a way, please explain what I have to do. It would be nice if you can provide CRC64 reverse samples, steps.

Regards,
Tushar

$random = md5(microtime() . “confusion and fustration in modern times”);

The thing is:
I’ve got a file with some binary content. There are multiple data blocks (Header, data, CRC code). They are separated by 00 bytes, like this:

———————————–
12 34 56 78 00 87 65 43 21 00 33 33 33 33

Header 00 Data 00 CRC code
———————————–

As you can see, the crc code is already embedded in the file.The file is checked by an application, and it compares the crc value of the whole file with the crc value, that is written into it. ( In this case 33 33 33 33).

With your method and your scripts, I created 4 “fakeTheCRC” bytes and appended them. Now the file had the CRC that were written into it. But there is still a problem.
The application checks if there is anything after the crc code (e.g. the “fake bytes”). So i have to go another way.

For now, It doesn’t matter which data is contained in the file, we can leave that out.

So for the correct crc, I have to:
1. Define a user-defined crc, e.g. 33 33 33 33
2. Calculate the data that is needed to get this crc

Now my problem is:
- How do I achieve this? I simply have to plan, I tried many many things, but I just don’t know what to do…

I hope you still answer questions after 5 years

Regards

By example, to extract the page topic, book and page and the number with this path: ‘/support/bash/8′ you must pass $default with
array(‘topic’ => ‘defaulttopic’,'book’=>’defaultbook’,'page’=>1)

The following elementh in the path will be returner in a name = value pairs as follows: (/support/bash/8/link/title1)

array(
‘topic’ => ‘support’,
‘book’ => ‘bash’,
‘page’ => 8,
‘link’ => ‘title1′,
)

Enjoy.

function router($default)
{
$keys = array_keys($default);
$pos = 0;
$res = array();
$name = isset($keys[$pos])?$keys[$pos]:”;
foreach(explode(‘/’,isset($_SERVER['PATH_INFO'])?$_SERVER['PATH_INFO']:”) as $value){
if($value != ”){
if($name == ”){
$name = $value;
}else{
$res[$name] = $value;
$pos++;
$name = isset($keys[$pos])?$keys[$pos]:”;
}
}
}
if($name != ”){ // Si se pasó un parámetro pero no su valor
$res[$name] = ”;
}
foreach($default as $key => $value){ // Valores default, por si no existen
if(!isset($res[$key]) || ($res[$key] == ”)){
$res[$key] = $value;
}
}
return $res;
}

I need a java library or algorithm to generate 4 bit CRC.
Can anyone plz help ?

Regards

return “#%02X%02X%02X” % (r,g,b) to get a 0 to show up as 00

ASP.NET, Java, FLEX are much better…