Principle and code of generating short URL in php_PHP tutorial

PHP generates short URL

Principle:

1. Verify the original URL with crc32 and get the check code.

2. Use sprintf('%u') to convert the check code into an unsigned number.

3. Perform a remainder 62 operation on unsigned numbers (uppercase and lowercase letters + numbers equal 62 bits), map the remainder to 62 characters, and save the mapped characters. (For example, the remainder is 10, then the mapped character is A, 0-9 corresponds to 0-9, 10-35 corresponds to A-Z, 35-62 corresponds to a-z)

4. Loop until the value is 0.

5. Splice all the mapped characters together to get the code after the short URL.

The code is as follows:

Copy code The code is as follows:

/**Generate short URL
* @param String $url Original URL
* @return String
*/
function dwz($url){

$code = sprintf('%u', crc32($url));

$surl = '';

while($code){
$mod = $code % 62;
if($mod>9 && $mod<=35){
$mod = chr($mod + 55);
}elseif($mod>35){
$mod = chr($mod + 61);
}
$surl .= $mod;
$code = floor($code/62 );
}

return $surl;

}

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