<?php
/**
 * php 根据自增id创建唯一编号类
 * Date:  2016-11-27
 * Author: fdipzone
 * Ver:   1.0
 *
 * Func
 * Public create 创建编号
 */
class IDCode{ // class start
  /**
   * 创建编号
   * @param Int  $id     自增id
   * @param Int  $num_length 数字最大位数
   * @param String $prefix   前缀
   * @return String
   */
  public static function create($id, $num_length, $prefix){
    // 基数
    $base = pow(10, $num_length);
    // 生成字母部分
    $division = (int)($id/$base);
    $word = '';
    while($division){
      $tmp = fmod($division, 26); // 只使用26个大写字母
      $tmp = chr($tmp + 65);   // 转为字母
      $word .= $tmp;
      $division = floor($division/26);
    }
    if($word==''){
      $word = chr(65);
    }
    // 生成数字部分
    $mod = $id % $base;
    $digital = str_pad($mod, $num_length, 0, STR_PAD_LEFT);
    $code = sprintf('%s-%s-%s', $prefix, $word, $digital);
    return $code;
  }
} // class end
?>

<?php
require 'IDCode.class.php';
$test_ids = array(1,9,10,99,100,999,1000,1009,2099,3999,9999,14999,99999);
foreach($test_ids as $test_id){
  echo $test_id.' = '.IDCode::create($test_id, 3, 'F').'<br>';
}
?>

1 = F-A-001
9 = F-A-009
10 = F-A-010
99 = F-A-099
100 = F-A-100
999 = F-A-999
1000 = F-B-000
1009 = F-B-009
2099 = F-C-099
3999 = F-D-999
9999 = F-J-999
14999 = F-O-999
99999 = F-VD-999