Lua学习笔记：分享一个用纯Lua写的位操作（异或）

前言

Lua在5.3���本之前没有进行位操作的运算符，如果想用一些位操作没有那么容易，可以使用BIt库来处理，这里分享几个使用纯Lua写的异或运算

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---

local floor = math.floor
function bxor (a,b)
  local r = 0
  for i = 0, 31 do
    local x = a / 2 + b / 2
    if x ~= floor (x) then
      r = r + 2^i
    end
    a = floor (a / 2)
    b = floor (b / 2)
  end
  return r
end

function bin_xor(x, y)
   local z = 0
   for i = 0, 31 do
      if (x % 2 == 0) then                      -- x had a '0' in bit i
         if ( y % 2 == 1) then                  -- y had a '1' in bit i
            y = y - 1 
            z = z + 2 ^ i                       -- set bit i of z to '1' 
         end
      else                                      -- x had a '1' in bit i
         x = x - 1
         if (y % 2 == 0) then                  -- y had a '0' in bit i
            z = z + 2 ^ i                       -- set bit i of z to '1' 
         else
            y = y - 1 
         end
      end
      y = y / 2
      x = x / 2
   end
   return z
end

XOR_l =
{ 
   {0,1},
   {1,0},
}
function xor(a,b)
   pow = 1
   c = 0
   while a > 0 or b > 0 do
      c = c + (XOR_l[(a % 2)+1][(b % 2)+1] * pow)
      a = math.floor(a/2)
      b = math.floor(b/2)
      pow = pow * 2
   end
   return c
end

都好使可以直接拿去用

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