上海苏韵酒店:哪位高手帮忙解说一下程序,满复杂的!

我看了这个程序好久,因为要用到,我又用VB把这个程序编写了一次,下边的是C程序代码,汉字是我的理解说明,请高手帮忙看看,如果我理解哪里的什么不对的请告诉我一下!非常感谢!其中的ComputeCRC是被调用的程序!!!!
var CRC_MARKER='.'

function Crc8Add(crc,c)
{

var Crc8Tab = new Array(
0x00,0x1B,0x36,0x2D,0x6C,0x77,0x5A,0x41,0xD8,0xC3,0xEE,0xF5,0xB4,0xAF,0x82,0x99,0xD3,0xC8,0xE5,
0xFE,0xBF,0xA4,0x89,0x92,0x0B,0x10,0x3D,0x26,0x67,0x7C,0x51,0x4A,0xC5,0xDE,0xF3,0xE8,0xA9,0xB2,
0x9F,0x84,0x1D,0x06,0x2B,0x30,0x71,0x6A,0x47,0x5C,0x16,0x0D,0x20,0x3B,0x7A,0x61,0x4C,0x57,0xCE,
0xD5,0xF8,0xE3,0xA2,0xB9,0x94,0x8F,0xE9,0xF2,0xDF,0xC4,0x85,0x9E,0xB3,0xA8,0x31,0x2A,0x07,0x1C,
0x5D,0x46,0x6B,0x70,0x3A,0x21,0x0C,0x17,0x56,0x4D,0x60,0x7B,0xE2,0xF9,0xD4,0xCF,0x8E,0x95,0xB8,
0xA3,0x2C,0x37,0x1A,0x01,0x40,0x5B,0x76,0x6D,0xF4,0xEF,0xC2,0xD9,0x98,0x83,0xAE,0xB5,0xFF,0xE4,
0xC9,0xD2,0x93,0x88,0xA5,0xBE,0x27,0x3C,0x11,0x0A,0x4B,0x50,0x7D,0x66,0xB1,0xAA,0x87,0x9C,0xDD,
0xC6,0xEB,0xF0,0x69,0x72,0x5F,0x44,0x05,0x1E,0x33,0x28,0x62,0x79,0x54,0x4F,0x0E,0x15,0x38,0x23,
0xBA,0xA1,0x8C,0x97,0xD6,0xCD,0xE0,0xFB,0x74,0x6F,0x42,0x59,0x18,0x03,0x2E,0x35,0xAC,0xB7,0x9A,
0x81,0xC0,0xDB,0xF6,0xED,0xA7,0xBC,0x91,0x8A,0xCB,0xD0,0xFD,0xE6,0x7F,0x64,0x49,0x52,0x13,0x08,
0x25,0x3E,0x58,0x43,0x6E,0x75,0x34,0x2F,0x02,0x19,0x80,0x9B,0xB6,0xAD,0xEC,0xF7,0xDA,0xC1,0x8B,
0x90,0xBD,0xA6,0xE7,0xFC,0xD1,0xCA,0x53,0x48,0x65,0x7E,0x3F,0x24,0x09,0x12,0x9D,0x86,0xAB,0xB0,
0xF1,0xEA,0xC7,0xDC,0x45,0x5E,0x73,0x68,0x29,0x32,0x1F,0x04,0x4E,0x55,0x78,0x63,0x22,0x39,0x14,
0x0F,0x96,0x8D,0xA0,0xBB,0xFA,0xE1,0xCC,0xD7);

return Crc8Tab[(crc^c)&0xFF]; 将Crc8Add传过来的两个数值先进行位异或运算,
得到的结果再与0xFF进行位与运算,得到一个0-255之间的数,将返回一个Crc8Tab数组中的值!
}

function Crc8Str(str)
{

var n;
var len=str.length;
var crc;

crc=0;
for (n=0; n<len; n++)
{
crc=Crc8Add(crc,str.charCodeAt(n)); 顺序得到str字符串中的字符的16进制的ASCII码,并用Crc8Add运算
}
return crc;
}

function ComputeCRC(str) 调用开始
{

var charSET="ABDEFGHMNQRTYadefghmnqrty2345789";
var CRC='';
var str2='';

if (str.length > 0)
{

//reverse str 反串字符串str
for(var i=0;i<str.length;i++)
str2=str.charAt(i)+str2;

CRC=CRC_MARKER;

//compute CRC 调用
var crc1=Crc8Str(str);
var crc2=Crc8Str(str2);

//map crcs to the charSET 调用
CRC+=charSET.charAt(crc1%(charSET.length-1));
CRC+=charSET.charAt(crc2%(charSET.length-1));
}
return CRC 得到结果
}