/// <summary>
/// Decoder step 1: get message header 10 bytes
/// </summary>
/// <param name="length"></param>
/// <param name="need"></param>
/// <returns>The decoder step to execute next.</returns>
private int DecoderStep1GetMessageHeader(ref int length, out int need)
{
if (!StreamDecoder.CheckAvailable(length, 10, out need))
{
return(1);
}
this.messageHeader = MessageHeader.Decode(new ReadOnlySpan <byte>(this.Buffer, this.decodeIndex, 10));
this.decodeIndex += 10;
this.messageDataLength -= 10;
length -= 10;
if (this.messageDataLength == 0)
{
if (this.messageHeader.MessageType == MessageType.DataMessage)
{
this.dataMessageHandler(this.messageHeader, new SecsMessage(this.messageHeader.S, this.messageHeader.F, string.Empty, replyExpected: this.messageHeader.ReplyExpected));
}
else
{
this.controlMessageHandler(this.messageHeader);
}
return(0);
}
if (length >= this.messageDataLength)
{
Trace.WriteLine("Get Complete Data Message with total data");
this.dataMessageHandler(this.messageHeader, new SecsMessage(this.messageHeader.S, this.messageHeader.F, string.Empty, StreamDecoder.BufferedDecodeItem(this.Buffer, ref this.decodeIndex), this.messageHeader.ReplyExpected));
length -= (int)this.messageDataLength;
this.messageDataLength = 0;
return(0); //completeWith message received
}
return(this.DecoderStep2GetItemHeader(ref length, out need));
}
/// <summary>
/// Decoder step 2: get _format + lengthBits(2bit) 1 byte
/// </summary>
/// <param name="length"></param>
/// <param name="need"></param>
/// <returns>The decoder step to execute next.</returns>
private int DecoderStep2GetItemHeader(ref int length, out int need)
{
if (!StreamDecoder.CheckAvailable(length, 1, out need))
{
return(2);
}
this.format = (SecsFormat)(this.Buffer[this.decodeIndex] & 0xFC);
this.lengthBits = (byte)(this.Buffer[this.decodeIndex] & 3);
this.decodeIndex++;
this.messageDataLength--;
length--;
return(this.DecoderStep3GetItemLength(ref length, out need));
}
/// <summary>
/// Decoder step 0: get total message length 4 bytes
/// </summary>
/// <param name="length"></param>
/// <param name="need"></param>
/// <returns>The decoder step to execute next.</returns>
private int DecoderStep0GetTotalMessageLength(ref int length, out int need)
{
if (!StreamDecoder.CheckAvailable(length, 4, out need))
{
return(0);
}
Array.Reverse(this.Buffer, this.decodeIndex, 4);
this.messageDataLength = BitConverter.ToUInt32(this.Buffer, this.decodeIndex);
Trace.WriteLine($"Get Message Length: {this.messageDataLength}");
this.decodeIndex += 4;
length -= 4;
return(this.DecoderStep1GetMessageHeader(ref length, out need));
}
/// <summary>
/// Decoder step 3: get _itemLength _lengthBits bytes, at most 3 byte
/// </summary>
/// <param name="length"></param>
/// <param name="need"></param>
/// <returns>The decoder step to execute next.</returns>
private int DecoderStep3GetItemLength(ref int length, out int need)
{
if (!StreamDecoder.CheckAvailable(length, this.lengthBits, out need))
{
return(3);
}
Array.Copy(this.Buffer, this.decodeIndex, this.itemLengthBytes, 0, this.lengthBits);
Array.Reverse(this.itemLengthBytes, 0, this.lengthBits);
this.itemLength = BitConverter.ToInt32(this.itemLengthBytes, 0);
Array.Clear(this.itemLengthBytes, 0, 4);
Trace.WriteLineIf(this.format != SecsFormat.List, $"Get format: {this.format}, length: {this.itemLength}");
this.decodeIndex += this.lengthBits;
this.messageDataLength -= this.lengthBits;
length -= this.lengthBits;
return(this.DecoderStep4GetItem(ref length, out need));
}
/// <summary>
/// Decoder step 4: get item value
/// </summary>
/// <param name="length"></param>
/// <param name="need"></param>
/// <returns>The decoder step to execute next.</returns>
private int DecoderStep4GetItem(ref int length, out int need)
{
need = 0;
Item item;
if (this.format == SecsFormat.List)
{
if (this.itemLength == 0)
{
item = Item.L();
}
else
{
this.stack.Push(new List <Item>(this.itemLength));
return(this.DecoderStep2GetItemHeader(ref length, out need));
}
}
else
{
if (!StreamDecoder.CheckAvailable(length, this.itemLength, out need))
{
return(4);
}
item = Item.BytesDecode(this.format, this.Buffer, this.decodeIndex, this.itemLength);
Trace.WriteLine($"Complete Item: {this.format}");
this.decodeIndex += this.itemLength;
this.messageDataLength -= (uint)this.itemLength;
length -= this.itemLength;
}
if (this.stack.Count == 0)
{
Trace.WriteLine("Get Complete Data Message by stream decoded");
this.dataMessageHandler(this.messageHeader, new SecsMessage(this.messageHeader.S, this.messageHeader.F, string.Empty, item, this.messageHeader.ReplyExpected));
return(0);
}
var list = this.stack.Peek();
list.Add(item);
while (list.Count == list.Capacity)
{
item = Item.L(this.stack.Pop());
Trace.WriteLine($"Complete List: {item.Count}");
if (this.stack.Count > 0)
{
list = this.stack.Peek();
list.Add(item);
}
else
{
Trace.WriteLine("Get Complete Data Message by stream decoded");
this.dataMessageHandler(this.messageHeader, new SecsMessage(this.messageHeader.S, this.messageHeader.F, string.Empty, item, this.messageHeader.ReplyExpected));
return(0);
}
}
return(this.DecoderStep2GetItemHeader(ref length, out need));
}
