本文介绍了php生成短网址的方法，以及php短网址的生成原理，将原网址做crc32校验，得到校验码，使用sprintf将校验码转为无符号数字，有需要的朋友参考下。
例1，php生成短网址。
复制代码 代码示例:
<?php
$chars=array("a","b","c","d","e","f","g","h",
"i","j","k","l","m","n","o","p",
"q","r","s","t","u","v","w","x",
"y","z","0","1","2","3","4","5",
"6","7","8","9","A","B","C","D",
"E","F","G","H","I","J","K","L",
"M","N","O","P","Q","R","S","T",
"U","V","W","X","Y","Z");
$salt="www.joneto.com";
$hash=md5("http://www.jb200.com".$salt);
$rs=array();
for($i=0;$i<4;$i++){
$temp=substr($hash, $i*8,8);
$temp=base_convert($temp, 16, 10) & base_convert("3fffffff", 16, 10);
$str="";
for($j=0;$j<6;$j++){
$subtemp=$temp & intval(base_convert("3d", 16, 10));
$str.=$chars[$subtemp];
$temp=$temp>>5;
}
unset($temp);
$rs[]=$str;
}
print_r($rs);
?>
php 生成短网址原理及代码
将原网址做crc32校验，得到校验码，使用sprintf将校验码转为无符号数字。
php 生成短网址 原理：
1.将原网址做crc32校验，得到校验码。
2.使用sprintf('%u') 将校验码转为无符号数字。
3.对无符号数字进行求余62操作（大小写字母+数字等于62位），得到余数后映射到62个字符中，将映射后的字符保存。（例如余数是10，则映射的字符是A，0-9对应0-9，10-35对应A-Z，35-62对应a-z）
4.循环操作，直到数值为0。
5.将所有映射后的字符拼接，就是短网址后的code。
复制代码 代码示例:
<?php
/** 生成短网址
* @param String $url 原网址
* @return String
*/
function dwz($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;
}
