public void TestWriteRead()
{
PackageHead target = new PackageHead();
PackageHead other = new PackageHead();
byte[] temp = new byte[PackageHead.SizeOf];
target.Flags = byte.MinValue;
target.MessageLength = ushort.MinValue;
target.WriteTo(temp, 0);
other.ReadFrom(temp, 0);
Assert.AreEqual(target, other);
target.Flags = (PackageHeadFlags)byte.MaxValue;
target.MessageLength = ushort.MaxValue;
target.WriteTo(temp, 0);
other.ReadFrom(temp, 0);
Assert.AreEqual(target, other);
Random random = new Random();
int index = random.Next(100);
temp = new byte[PackageHead.SizeOf + 100];
target.Flags = (PackageHeadFlags)12;
target.MessageLength = 16;
target.WriteTo(temp, index);
other.ReadFrom(temp, index);
Assert.AreEqual(target, other);
}
/// <summary>
/// 序列化要发送的message
/// </summary>
public TcpSession.SendingHandler CreateSendingHandler()
{
TcpSession.SendingHandler handler = (messages, stream) =>
{
foreach (var message in messages)
{
// 保留包头空间
var headerPosition = stream.Position;
stream.SetLength(stream.Length + PackageHead.SizeOf);
stream.Position += PackageHead.SizeOf;
// 序列化消息
serializer.Serialize(message, stream);
PackageHead header = new PackageHead();
var length = stream.Length - (headerPosition + PackageHead.SizeOf);
// 超大包
if (length > ushort.MaxValue)
{
// 写入第一个包的包头
header.Flags |= PackageHeadFlags.Partial;
header.MessageLength = ushort.MaxValue;
header.WriteTo(stream.GetBuffer(), (int)headerPosition);
length -= ushort.MaxValue;
// 从第一个包末尾截断，把剩余数据拷到临时缓冲中
var keptSize = headerPosition + ushort.MaxValue + PackageHead.SizeOf;
var dataLeft = new byte[stream.Length - keptSize];
var offset = 0;
stream.Position = keptSize;
stream.Read(dataLeft, 0, dataLeft.Length);
stream.Position = keptSize;
stream.SetLength(keptSize);
// 从临时缓冲中把剩余数据加上包头写入
while (length > 0)
{
ushort truncateLength = ushort.MaxValue;
// 最后的部分
if (length <= ushort.MaxValue)
{
truncateLength = (ushort)length;
header.Flags &= ~PackageHeadFlags.Partial;
}
header.MessageLength = truncateLength;
header.WriteTo(stream);
stream.Write(dataLeft, offset, truncateLength);
offset += truncateLength;
length -= truncateLength;
}
Debug.Assert(offset == dataLeft.Length);
}
else // 普通大小的包
{
// 写入包头
header.MessageLength = (ushort)length;
header.WriteTo(stream.GetBuffer(), (int)headerPosition);
}
}
};
return handler;
}
