/// <summary>
/// 字符串加密，原理：开头4字节+每个字节的补偿长度(len*2)+内容len+校验码（1）
///
/// </summary>
/// <param name="source"></param>
/// <returns></returns>
public byte[] Encode(byte[] source)
{
if (source == null || source.Count() == 0)
{
throw new Exception("source is null");
}
int lenth = source.Count();
List <short> offsetList = new List <short>();
List <byte> content = new List <byte>();
for (int i = 0; i < lenth; i++)
{
short offset = Encode(source[i]);
offsetList.Add(offset);
content.Add((byte)(source[i] + offset));
}
List <byte> result = new List <byte>();
//加入字节长度:4
result.AddRange(BitConverter.GetBytes(lenth));
//加入offset 2*lenth
offsetList.ForEach(x => result.AddRange(BitConverter.GetBytes(x)));
//加入内容：lenth
content.ForEach(x => result.Add(x));
//加入校验码
result.Add(XORHelper.GetXORCode(result));
return(result.ToArray());
}
public byte[] Decode(byte[] source)
{
if (source == null || source.Length == 0)
{
throw new Exception("soure is null");
}
if (source.Length < 4)
{
throw new Exception("invalid source");
}
byte xorCode = XORHelper.GetXORCode(source, 0, source.Length - 1);
if (xorCode != source[source.Length - 1])
{
throw new Exception("invalid checksum");
}
int lenth = BitConverter.ToInt32(source, 0);
if (source.Length != 4 + lenth * 2 + lenth + 1)
{
throw new Exception("invalid lenth");
}
List <short> offsetList = new List <short>();
List <byte> content = new List <byte>();
for (int i = 4; i < 4 + lenth * 2; i += 2)
{
offsetList.Add(BitConverter.ToInt16(source, i));
}
for (int i = 4 + lenth * 2; i < 4 + lenth * 2 + lenth; i++)
{
content.Add(source[i]);
}
//除去补偿值
for (int i = 0; i < lenth; i++)
{
content[i] = (byte)(content[i] - offsetList[i]);
}
return(content.ToArray());
}
