php產生短網址原理與執行個體

例1，php產生短網址。 $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"; $hash=md5("http://bbs.it-home.org".$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); ?> 複製代碼 php 產生短網址原理及代碼 將原網址做crc32校正，得到校正碼，使用sprintf將校正碼轉為無符號數字。 php 產生短網址 原理： 1.將原網址做crc32校正，得到校正碼。 2.使用sprintf('%u') 將校正碼轉為無符號數字。 3.對無符號數字進行求餘62操作（大小寫字母+數字等於62位），得到餘數後映射到62個字元中，將映射後的字元儲存。（例如餘數是10，則映射的字元是A，0-9對應0-9，10-35對應A-Z，35-62對應a-z） 4.迴圈操作，直到數值為0。 5.將所有映射後的字元拼接，就是短網址後的code。 /** 產生短網址 * @param String $url 原網址 * @return String */ function dwz($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; } 複製代碼

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