public void Serialize(ref JT809MessagePackWriter writer, JT809Package value, IJT809Config config)
{
// -----------开始组包----------
// 1.起始符
writer.WriteByte(value.BeginFlag);
// 2.写入头部数据
// 2.1.跳过数据长度的写入
writer.Skip(4, out int lengthPosition);
// 2.2.报文序列号
value.Header.MsgSN = value.Header.MsgSN > 0 ? value.Header.MsgSN : config.MsgSNDistributed.Increment();
writer.WriteUInt32(value.Header.MsgSN);
// 2.3.业务数据类型
writer.WriteUInt16(value.Header.BusinessType);
// 2.4.下级平台接入码
writer.WriteUInt32(value.Header.MsgGNSSCENTERID);
// 2.5.版本号
writer.WriteArray(value.Header.Version.Buffer);
// 2.6.报文加密
writer.WriteByte((byte)value.Header.EncryptFlag);
// 2.7.数据加密密钥
writer.WriteUInt32(value.Header.EncryptKey);
// 3.写入数据体
// 3.1.记录当前开始位置
int startIndex = writer.GetCurrentPosition();
// 3.2.写入数据对应数据体
if (value.Bodies != null)
{
JT809MessagePackFormatterResolverExtensions.JT809DynamicSerialize(
config.GetMessagePackFormatterByType(value.Bodies.GetType()),
ref writer, value.Bodies,
config);
}
// 3.3.记录当前结束位置
int endIndex = writer.GetCurrentPosition();
int contentLength = endIndex - startIndex;
if (contentLength > 0)
{
// 3.4. 数据加密
switch (value.Header.EncryptFlag)
{
case JT809Header_Encrypt.None:
break;
case JT809Header_Encrypt.Common:
// 3.5. 提取数据体并进行加密处理
byte[] messageBodyDatEncrypted = config.Encrypt.Encrypt(writer.Extract(startIndex), config.EncryptOptions, value.Header.EncryptKey);
int flagLength = messageBodyDatEncrypted.Length - contentLength;
if (flagLength == 0)
{
// 相等复制
writer.CopyTo(messageBodyDatEncrypted, startIndex);
}
else if (flagLength > 0)
{
// 扩容
writer.Skip(flagLength, out _);
writer.CopyTo(messageBodyDatEncrypted, startIndex);
}
else
{
// 缩减
writer.CopyTo(messageBodyDatEncrypted, startIndex);
writer.Shrink(-flagLength);
}
break;
}
}
// 4.计算内容的总长度(校验码2+终止符1=3)
writer.WriteInt32Return(writer.GetCurrentPosition() + 3, lengthPosition);
// 5.校验码
writer.WriteCRC16();
// 6.终止符
writer.WriteByte(value.EndFlag);
// 7.转义
writer.WriteEncode();
// -----------组包完成----------
}