str_rot13()

(PHP 4 >= 4.2.0, PHP 5, PHP 7)

对字符串执行 ROT13 转换

说明

对$str参数执行 ROT13 编码并将结果字符串返回。

ROT13 编码简单地使用字母表中后面第 13 个字母替换当前字母，同时忽略非字母表中的字符。编码和解码都使用相同的函数，传递一个编码过的字符串作为参数，将得到原始字符串。

参数

输入字符串。

返回值

返回给定字符串的 ROT13 版本。

范例

Example #1str_rot13()范例

I was reminded again of the desire for a generic str_rot function. Character manipulation loops in PHP are slow compared to their C counterparts, so here's a tuned version of the previous function I posted. It's 1.6 times as fast, mainly by avoiding chr() calls.

But using strtr() you can get something 10 times as fast as the above :

This technique is faster because PHP's strtr is implemented in C using a byte lookup table (it has O(m + n) complexity). However, PHP 6 will use Unicode, so I guess(?) strtr will then have to be implemented with a search for each character (O(m * n)). Using strtr might still be faster since it offloads the character manipulation to C rather than PHP, but I don't really know. Take your pick.
Happy coding!
(Benchmark code):

This ROT13 variant is different from my earlier version in that it retains 'ethnicity'. For example, a Chinese text when encrypted will remain Chinese, and the string will not be making sense (the real meaning will be encrypted). Just look at the code and you will understand.

A nice, simple way of using rot-n. Allows for a lot of easy customisation, and works quickly. This function uses ASCII characters and values.

//===== RESULT =====
Crgre'f 62 crgf (vapy. 0 unzfgref) ybir Qe Fnenu Tvofba, QIZ!
Crgre"f 62 crgf [vapy: 0 unzfgref] ybir Qe Fnenu Tvofba; QIZ?
Jynyl'm 17 jynm (chwf. 5 bugmnylm) fipy Xl Mulub Acvmih, XPG!
Yncna'b 40 yncb (rwlu. 8 qjvbcnab) uxen Ma Bjajq Prkbxw, MEV!
Prgre'f 62 crgf (vapy. 0 unzfgref) ybir De Snenu Gvofba, DVM!
1. The basic parameters are the string and the percentage, 50 by default. The next four parameters allow to select which type of characters to process. There is a good reason why I put less common types first, and most obvious last. To activate extra characters you need only 1 additional parameter, otherwise you would need 4 enabling also the obvious types.
2. The definition for the letters and digits is obvious. For the extra characters I chose kind of pairs that make sense when shifted by 50%, e.g. () => [] or & => + etc. Of course you can adjust those characters to anything you like.
3. The first step is to clean the percentage, and also allow "real" floats, e.g. 1/3 for 33.33%. 
4. The next step secures great flexibility when using the function. As described, instead of 4 boolean parameters you can pass 1 array. E.g. the array('upper' => TRUE) will enable the change of uppercase letters only.
5. Finally the function goes through every type and shifts the characters according to the given percentage.
I hope you can use this function and do some fancy stuff with it. Rotating characters doesn't really make sense, but it can be fun.
Arthur :-)

My own generic rotN function

Perhaps someone will find this useful ;)

It takes any string, $s, and any ROT value, $n. Just like str_rot13, it's both an encoder and decoder. To decode an encoded string, just pass -$n instead of $n.

/**
SALVAJE COMENTARIO EN ESPAÑOL XD
*/

here's my rot function, it works anyway

Here's my implementation of a str_rot that takes a custom offset. It's faster than the others here because it allocates the output string in one go instead of tacking on characters one at a time. It can handle positive or negative offsets of any size, and it fixes everything up to ensure only upper and lower case letters are translated and that they wrap around correctly within the alphabet.

Below is a short function that allows you to rotate a string which includes non alphabetic characters you choose.
By running the code without the second argument you can both obfuscate then de-obfuscate. This isn't a safe form of encryption, just a quick way to hide stuff from the casual viewer.
function str_rot($s, $n = -1) {
  //Rotate a string by a number.
  static $letters = 'AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz0123456789.,!$*+-?@#'; //To be able to de-obfuscate your string the length of this needs to be a multiple of 4 AND no duplicate characters
  $letterLen=round(strlen($letters)/2);
  if($n==-1) $n=(int)($letterLen/2); //Find the "halfway rotate point"
  $n = (int)$n % ($letterLen);
  if (!$n) return $s;
  if ($n ";

Here is my ROT13 function that works for all possible characters and not just ASCII. It can be used on Chinese, Japanese, ....

鹏仔微信 15129739599 鹏仔QQ344225443 鹏仔前端 pjxi.com 共享博客 sharedbk.com