Mssql binary_checksum in LUA

Question

我想把MSSQL语言的binary_checksum从c#翻译成Lua，但我是Lua的新手...

private static int SQLBinaryChecksum(string text)
{
    long sum = 0;
    byte overflow;
    for (int i = 0; i < text.Length; i++)
    {
        sum = (long)((16 * sum) ^ Convert.ToUInt32(text[i]));
        overflow = (byte)(sum / 4294967296);
        sum = sum - overflow * 4294967296;
        sum = sum ^ overflow;
    }

    if (sum > 2147483647)
        sum = sum - 4294967296;
    else if (sum >= 32768 && sum <= 65535)
        sum = sum - 65536;
    else if (sum >= 128 && sum <= 255)
        sum = sum - 256;

    return (int)sum;
}

Answer 1

您没有指定您的Lua版本，所以我建议您使用LuaJIT。

-- Works only on LuaJIT
function SQLBinaryChecksum(text)
   local sum = 0
   for i = 1, #text do
      sum = bit.bxor(bit.rol(sum, 4), text:byte(i))
   end
   if sum >= 32768 and sum <= 65535 then
      sum = sum - 65536
   elseif sum >= 128 and sum <= 255 then
      sum = sum - 256
   end
   return sum
end
-- Did you notice that Lua code is shorter than C#?

如果文本包含ASCII以外的字符，则此代码可能无法正常工作。

要解决这个问题，我应该知道字符串€的正确校验和