代码 复制 - 运行

function decode($str,$num=0){  
$c5=array(-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,  41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1); 
$c6 = ord(substr($str,0,1)); 
if($num==0) 
{ 
$c7=$this->decode($str,1); 
$str = substr($c7,$c6); 
};  
$len = strlen($str);  
$i = 1;  
$out = "";  
while($i < $len) {  
do {  
$c1 = $c5[ord(substr($str,$i++,1)) & 0xff]; 
}  

while($i < $len && $c1 == -1);  
if($c1 == -1) break;  
do {$c2 = $c5[ord(substr($str,$i++,1)) & 0xff]; }  
while($i < $len && $c2 == -1);  
if($c2 == -1) break;  
$out .= $this->fromCharCode(($c1 << 2) | (($c2 & 0x30) >> 4));  
do { $c3 = ord(substr($str,$i++,1)) & 0xff; if($c3 == 61) return $out; $c3 = $c5[$c3]; }  
while($i < $len && $c3 == -1);  
if($c3 == -1) break;  
$out .= $this->fromCharCode((($c2 & 0XF) << 4) | (($c3 & 0x3C) >> 2));  
do { $c4 = ord(substr($str,$i++,1)) & 0xff;if($c4 == 61) return $out; $c4 = $c5[$c4]; }  
while($i < $len && $c4 == -1);  
if($c4 == -1) break;  
$out.= $this->fromCharCode((($c3 & 0x03) << 6) | $c4); }  
return $out; 
} 
function fromCharCode($num){ 
return chr($num); 
}


来源:http://blog.csdn.net/aicoder/archive/2009/05/12/4174299.aspx