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  Work with MySQL character set and collation

For non-English websites, they often have to deal with character set and collation if they want to store data to and read data from databases with other languages. Character set tells the database which kind of character encoding scheme to use to store or read data, collation can be simply understood as a subset of character set, it tells the database how to sort data. We talk about working with character set and collation of MySQL today.  In MySQL, if we want to store Chinese, Japanese or ...

   MySQL,character set,collation,Chinese,question mark     2012-06-17 07:07:28

  Generate certificate from cert file in Java

A certificate is often used to prove the identity of a server. The certificate will contain information such as the subject and issuer of the certificate. It will also contain the validation date of the certificate. A certificate is often exported to an external cert file which is transferred over the internet. We will often see its use in SSL communication which provides secure communication between two entities. In this post, we will show how to read the data from an external certificate file ...

   PKCS12,CertificateFactory,Example,Java,X509     2015-06-08 06:47:05

  Cracking Siri

On October 14, 2011, Apple introduced the new iPhone 4S. One of its major new features was Siri, a personal assistant application. Siri uses a natural language processing technology to interact with the user.Interestingly, Apple explained that Siri works by sending data to a remote server (that’s probably why Siri only works over 3G or WiFi). As soon as we could put our hands on the new iPhone 4S, we decided to have a sneak peek at how it really works.Today, we managed to crack ...

   Siri,Cracking,Defect,Speech to text,Record,AI     2011-11-15 08:38:23

  Latest PHP patch cannot fix the bug

On Wednesday(2012-05-02), a remote code execution vulnerability in PHP was accidentally exposed to the Web, prompting fears that it may be used to target vulnerable websites on a massive scale. The bug itself was traced back to 2004, and came to light during a recent CTF competition.A CERT advisory on the flaw explains: “When PHP is used in a CGI-based setup (such as Apache's mod_cgid), the php-cgi receives a processed query string parameter as command line arguments which allows com...

   PHP,bug,patch,bypassed     2012-05-08 11:20:56

  Using JavaScript to operate clipboard

Browsers allow JavaScript to read and write data on clipboard. Generally script should not modify user's clipboard to avoid impacting user expectation, but there are cases where this can indeed bring convenience to users. For example, for some code snippet, user can copy it to clipboard with one click instead of select and copy manually. There are three options for clipboard operation provided in JavaScript/browser: document.execCommand() Asynchronous Clipboard API copy and paste events This p...

   JAVASCRIPT,CLIPBOARD,NAVIGATOR.CLIPBOARD     2021-01-23 23:23:34

  Why 0.1+0.2 != 0.3

In programming languages such as JavaScript, c/c++, Java and Matlab, you will find that you will get unexpected result when doing float point calculation. For example, when calculating 0.1 + 0.1, you will not get 0.3: > 0.1 + 0.2 == 0.3 false > 0.1 + 0.2 0.30000000000000004 Don't be surprised of this result, this is the end result of IEEE 754 standard, float point number cannot be accurately represented according to IEEE 754 because: No enough memory is allocated for representing the num...

   float point,comparison,JavaScript     2014-11-19 05:32:46

  Three things you should never put in your database

As I've said in a few talks, the best way to improve your systems is by first not doing "dumb things". I don't mean you or your development staff is "dumb", it's easy to overlook the implications of these types of decisions and not realize how bad they are for maintainability let alone scaling. As a consultant I see this stuff all of the time and I have yet to ever see it work out well for anyone. Images, files, and binary data Your database supports BLOBs so it must be a good idea to shove ...

   Database,BLOB,Log,Image     2012-05-02 04:44:25

  Reducing Code Nesting

"This guy’s code sucks!" It’s something we’ve all said or thought when we run into code we don’t like. Sometimes it’s because it’s buggy, sometimes it’s because it conforms to a style we don’t like, and sometimes it’s because it just feels wrong. Recently I found myself thinking this, and automatically jumping to the conclusion that the developer who wrote it was a novice. The code had a distinct property that I dislike: lots of ...

   Code nesting,Readability,Maintainability,Reduction     2012-01-02 08:13:46

  Fix issue where no Java virtual machine found when launching Eclipse

In cases where a new Eclipse is installed or the location of the Java virtual machine binaries has been changed, you may face issue when launching Eclipse. The error would look like. And if you go to the location specified in the error message, there is no such path indeed.  And when clicks OK, the program just exits. The issue here is that it tries to find the java.exe binary and launch the program but it failed to locate it and hence exits. To fix this, you first need to ensure you have...

   ECLIPSE,JAVA,LAUNCH,ECLIPSE.INI     2019-09-07 05:31:27

  Supercolliding a PHP array

Did you know that inserting 2^16 = 65536 specially crafted values into a normal PHP array can take 30 seconds? Normally this would take only 0.01 seconds. This is the code to reproduce it: <?php echo '<pre>'; $size = pow(2, 16); // 16 is just an example, could also be 15 or 17 $startTime = microtime(true); $array = array(); for ($key = 0, $maxKey = ($size - 1) * $size; $key <= $maxKey; $key += $size) { $array[$key] = 0; } $endTime = microtime(true); echo 'Inserting...

   PHP,Array,hashtable,Slow,Colliding     2011-12-29 09:02:01

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