The read method on a networkstream blocks only until the first byte is available.
It is not guaranteed to read the desired count into the buffer.
This solution tries to read the remaining bytes in a loop and aborts once the
full count is read or the Stream.Read method returns with 0 or less bytes read.
The synchronous read can block indefinitly if the lenght field is larger than the send package.
This requires reference types that can be null to be annotated by a ? operator, similar to value types.
This gives the advantage that the compiler can warn against any null dereference exceptions, of which this commits elimits a few.
To make the underlying protocol implementation not any more complicated and to eliminate existing problems, and not that precise error reporting, I replaced some return null statements with explicit Exceptions. This lead to the assumption that those core protocoll functions always return non-null objects if they do not throw, making the PLC code simpler.
Adjust some NotConnected tests to look for explicit PlcException instead of NullReferenceException.
Revert back to using Stream/TcpClient. High performance stuff is moved
to highperformancesockets branch. I think this is interesting, but i also
feel that this is premature optimization. I doubth that this will be a
performance bottleneck ofr the forseeable future.
This reverts commit 1b34716a30.
Note: This keeps the old methods to be backward compatible.
Note: Unforntunatly a lot of whitespace fixes, refactoring and other trivial stuff is
included. It was to hard to split of in a seperate commit.
Note: Async methods does not use exactly the same structure/signature as the
existing methods. "Out" parameters like ReadClass and ReadStruct instead
returns the struct in tuple. Async methods also rely on exceptions
instead of ErrorCodes to communicate exception states to calling client.
* Use TcpClient and use Async methods (ReadAsync/WriteAsync)
* Implemnt async methods for all existing methods
* Implemnt existing methods using tcpclient.
* Split Plc.cs in more files. (Common, Async, Sync, Helpers)
* Mark old methods as Obsolete
* Split tests in two files
* Implement Async tests
Read responses from the PLS using classes for TPKT and COPT. This
makes the communication more robust. It will now handle empty COTP
packets that SoftPLS and WinAC based PLCs send out. I use RFC names for
functions and classes.
Change logic to use COTP and S7Comm reponse codes instead of
relying on packet sizes.
Read Max PDU size from connection setup. Ref #21
Change logic to use MaxPDUSize when reading istead of hardcoded limit.
I tried using MaxPDUSize when writing data but this failed when packet size is
over 256 on snap7. So i decided to drop changes to write size.
I have done some tests against WinAC cpu and it seems to handle bigger pdu's
when writing if negotiated in the connection setup. This might just be a SNAP7 bug.
Fix MaxPDUSize for readbytes
Remove debug line
Simplify byte copy. Remove unessesarry buffer
Read responses from the PLS using classes for TPKT and COPT. This
makes the communication more robust. It will now handle empty COTP
packets that SoftPLS and WinAC based PLCs send out. I use RFC names for
functions and classes.
Change logic to use COTP and S7Comm reponse codes instead of
relying on packet sizes.
Read Max PDU size from connection setup. Ref #21
Change logic to use MaxPDU from cpu limit instead of hardcoded limit.
Remove var count limit.
