本文實例講述了php生成固定長度純數字編碼的方法。分享給大家供大家參考。具體如下：

很多時候我們需要一些固定長度的數字編碼，如訂單編號、卡號、用戶編號等等！但是經常我們有的是存儲在數據庫中的有序編號，我們可以通過它直接轉成一個固定長度的數字編碼，然后更新到數據庫中形成此記錄的唯一編號。

<?php

/**

* 根據日期或者是給定前綴生成唯一編號

* User: minyifei.cn

* Date: 15/7/7

*/

namespace Minyifei/Libs;

class SequenceNumber {

/**

* 根據顯示寬度獲取指定的 mapbit

*

* @param integer $width 編號顯示寬度

*

* @return array

*/

private static function _getMapbit($width)

{

$mapBits = array(

4=>array(

10, 2, 11, 3, 0, 1, 9, 7, 12, 6, 4, 8, 5,

),

5=>array(

4, 3, 13, 15, 7, 8, 6, 2, 1, 10, 5, 12, 0, 11, 14, 9,

),

6=>array(

2, 7, 10, 9, 16, 3, 6, 8, 0, 4, 1, 12, 11, 13, 18, 5, 15, 17, 14,

),

7=>array(

18, 0, 2, 22, 8, 3, 1, 14, 17, 12, 4, 19, 11, 9, 13, 5, 6, 15, 10, 16, 20, 7, 21,

),

8=>array(

11, 8, 4, 0, 16, 14, 22, 7, 3, 5, 13, 18, 24, 25, 23, 10, 1, 12, 6, 21, 17, 2, 15, 9, 19, 20,

),

9=>array(

24, 23, 27, 3, 9, 16, 25, 13, 28, 12, 0, 4, 10, 18, 11, 2, 17, 1, 21, 26, 5, 15, 7, 20, 22, 14, 19, 6, 8,

),

10=>array(

32, 3, 1, 28, 21, 18, 30, 7, 12, 22, 20, 13, 16, 15, 6, 17, 9, 25, 11, 8, 4, 27, 14, 31, 5, 23, 24, 29, 0, 10, 19, 26, 2,

),

11=>array(

9, 13, 2, 29, 11, 32, 14, 33, 24, 8, 27, 4, 22, 20, 5, 0, 21, 25, 17, 28, 34, 6, 23, 26, 30, 3, 7, 19, 16, 15, 12, 31, 1, 35, 10, 18,

),

12=>array(

31, 4, 16, 33, 35, 29, 17, 37, 12, 28, 32, 22, 7, 10, 14, 26, 0, 9, 8, 3, 20, 2, 13, 5, 36, 27, 23, 15, 19, 34, 38, 11, 24, 25, 30, 21, 18, 6, 1,

),

);

return $mapBits[intval($width)];

}

/**

* 格式化給定時間戳

*

* @param integer $ts timestamp, if null use current timestamp

*

* @return string

*/

private static function _fmtTS($ts=null)

{

$ts = $ts ?: time();

return date(self::$_fmt, $ts);

}

/**

* 根據id獲取一個隨機唯一編碼

* @param $id 編號

* @param int $prefix 前綴

* @param int $width 除前綴外長度

* @return string

*/

public static function generateNumber($id,$prefix=10,$width=8)

{

return sprintf("%s%s", $prefix,self::encode($id, $width));

}

/**

* 編碼轉換

*

* @param integer $id id

* @param integer $width 編號額外組成部分的顯示寬度

*

* @return integer

*/

public static function encode($id, $width)

{

$maximum = intval(str_repeat(9, $width));

$superscript = intval(log($maximum) / log(2));

$r = 0;

$sign = 0x1 << $superscript;

$id |= $sign;

$mapbit = self::_getMapbit($width);

for ($x = 0; $x < $superscript; $x++) {

$v = ($id >> $x) & 0x1;

$r |= ($v << $mapbit[$x]);

}

$r += $maximum - pow(2, $superscript) + 1;

return sprintf("%0${width}s", $r);

}

/**

* 獲取唯一編號

*

* @param integer $id id, mostly database primary key

* @param integer $width 編號顯示寬度

* @param integer $ts timestamp

*

* @return string

*/

public static function get($id, $width, $ts=null)

{

return sprintf('%s%s', self::_fmtTS($ts), self::encode($id, $width));

}

}

希望本文所述對大家的php程序設計有所幫助。