lua 5.1ビット演算

--[[
       
    --      1，  1
    --        1，  1
    --    true  false，   true
    --      0，   1
]]


local MathBit = {}


function MathBit.__andBit(left,right)    -- 
    return (left == 1 and right == 1) and 1 or 0
end

function MathBit.__orBit(left, right)    -- 
    return (left == 1 or right == 1) and 1 or 0
end

function MathBit.__xorBit(left, right)   --  
    return (left + right) == 1 and 1 or 0
end

function MathBit.__base(left, right, op) --      op  ，      
    if left < right then
        left, right = right, left
    end
    local res = 0
    local shift = 1
    while left ~= 0 do
        local ra = left % 2    --     (   )
        local rb = right % 2
        res = shift * op(ra,rb) + res
        shift = shift * 2
        left = math.modf( left / 2)  --  
        right = math.modf( right / 2)
    end
    return res
end


function MathBit:andOp(left, right)
    return MathBit.__base(left, right, MathBit.__andBit)
end

function MathBit:xorOp(left, right)
    return MathBit.__base(left, right, MathBit.__xorBit)
end

function MathBit:orOp(left, right)
    return MathBit.__base(left, right, MathBit.__orBit)
end

function MathBit:notOp(left)
    return left > 0 and -(left + 1) or -left - 1
end

function MathBit:lShiftOp(left, num)  --left  num 
    return left * (2 ^ num)
end

function MathBit:rShiftOp(left,num)  --right  num 
    return math.floor(left / (2 ^ num))
end

return MathBit