通過 bitwise 方式來判斷權限

bitwise.php

<?php

    $premissionA = 1;		// 1
    $premissionB = 1 << 1;  // 2	
    $premissionC = 1 << 2;  // 4
    $premissionD = 1 << 3;  // 8
    $premissionE = 1 << 4;  // 16
    $premissionF = 1 << 5;  // 32
    $premissionG = 1 << 6;  // 64
    $premissionH = 1 << 7;  // 128
    $premissionI = 1 << 8;  // 256
    $premissionJ = 1 << 9;  // 512

    // Users 直接用 OR 的方式來 chain 權限，或者直接給數字
    $administrator = $premissionA | $premissionB | $premissionC | $premissionD | $premissionJ;
    $developer	   = 100;
    // developer 只有 premissionH + premissionG + premissionD
    // 01100100 = 100  
   
    // ★★★★★★★★★★★★ 這樣會錯 ★★★★★★★★★★★★ 不能用加號
    $moderator     = $premissionA + $premissionB + $premissionC + $premissionD;

    // function to check for permission
    function checkPermission($user, $permission) {  return ($user & $permission); }
    function deletePermission($user, $permission) {  if (checkPermission($user, $premissionJ)) { return ($user ^ $permission); }}

    echo 
    (checkPermission($administrator, $premissionJ) 
    ? "have premissionJ"      		/// 有 J 
    : "do not have premissionJ");

    echo 
    (checkPermission($developer, $premissionB) 
    ? "do have premissionB"       
    : "do not have premissionB");  	/// 沒有 B

    echo 
    (checkPermission($developer, $premissionH) 
    ? "do have premissionH"		 	/// 有 H 
    : "do not have premissionH");

    echo 
    (deletePermission($developer, $premissionH) 
    ? "do have premissionH"		 
    : "do not have premissionH");	/// 沒有 H 

?>