Lua位操作實現CRC16算法

基於Lua5.3

function crc16(buf,len)
    local init = 0xFFFF;
    local poly = 0xA001;

    local ret = init;
    local byte=0;

    for j=1,len,1 do
        byte = string.byte(buf,j);
        ret=((ret ~ byte) & 0xFFFF);

        for i=1,8,1 do
            if((ret & 0x0001)>0) then
                ret = (ret >> 1);
                ret = ((ret ~ poly) & 0xFFFF);
            else
                ret= (ret >> 1);
            end;
        end
    end

    local hi = ((ret >> 8) & 0xFF);
    local lo = (ret & 0xFF);
    ret = ((lo << 8) | hi);

    return ret;
end

使用方法：

local data = string.pack("BBBBBB", 0x01, 0x03, 0x00, 0x00, 0x00, 0x02);	--需要校驗CRC16的內容
local datacrc = crc16(data,6);

print( datacrc >> 8 )		--輸出196 == 0xC4
print( datacrc & 0xFF )		--輸出11  == 0x0B

檢查正確性