Feature/optimize 02 datatypes getvalue maxstringlength

src/S7CommPlusDriver/ClientApi/PlcTag.cs

@@ -64,6 +64,26 @@ public virtual void ProcessWriteResult(UInt64 error)
 
         internal abstract PValue GetWriteValue();
 
+        /// <summary>
+        /// Gets the tag's current typed value as a boxed <see cref="object"/> via its public <c>Value</c> property.
+        /// </summary>
+        /// <returns>The boxed value, or <see langword="null"/> when the concrete tag type has no public <c>Value</c> property.</returns>
+        public virtual object GetValue()
+        {
+            var valueProperty = GetType().GetProperty("Value", BindingFlags.Public | BindingFlags.Instance);
+            return valueProperty?.GetValue(this);
+        }
+
+        /// <summary>
+        /// Sets the tag's current typed value from a boxed <see cref="object"/> via its public <c>Value</c> property.
+        /// </summary>
+        /// <param name="value">The value to assign, which must be assignable to the concrete tag's <c>Value</c> property type.</param>
+        public virtual void SetValue(object value)
+        {
+            var valueProperty = GetType().GetProperty("Value", BindingFlags.Public | BindingFlags.Instance);
+            valueProperty?.SetValue(this, value);
+        }
+
         internal void SetTraceAddressMetadata(VarInfo variable)
         {
             if (variable == null)

src/S7CommPlusDriver/Core/POffsetInfoType.cs

@@ -69,6 +69,12 @@ public enum OffsetInfoType
         public abstract bool Is1Dim();
         public abstract bool IsMDim();
 
+        /// <summary>
+        /// Gets the maximum string length for a String/WString offset info, or 0 when not applicable.
+        /// </summary>
+        /// <returns>The maximum length in characters, or 0 for non-string offset info types.</returns>
+        public virtual int MaxStringLength() { return 0; }
+
         public static POffsetInfoType Deserialize(Stream buffer, int offsetinfotype, out int length)
         {
             switch ((OffsetInfoType)offsetinfotype)
@@ -455,6 +461,8 @@ public class POffsetInfoType_ArrayMDim : POffsetInfoType, IOffsetInfoType_MDim
         public override bool HasRelation() { return false; }
         public override bool Is1Dim() { return false; }
         public override bool IsMDim() { return true; }
+        // For a string array, UnspecifiedOffsetinfo1 carries the maximum string length of the array elements.
+        public override int MaxStringLength() { return UnspecifiedOffsetinfo1; }
 
         public static POffsetInfoType_ArrayMDim Deserialize(Stream buffer, out int length)
         {
@@ -542,6 +550,8 @@ public class POffsetInfoType_Array1Dim : POffsetInfoType, IOffsetInfoType_1Dim
         public override bool HasRelation() { return false; }
         public override bool Is1Dim() { return true; }
         public override bool IsMDim() { return false; }
+        // For a string array, UnspecifiedOffsetinfo1 carries the maximum string length of the array elements.
+        public override int MaxStringLength() { return UnspecifiedOffsetinfo1; }
 
         public static POffsetInfoType_Array1Dim Deserialize(Stream buffer, out int length)
         {
@@ -599,6 +609,8 @@ public class POffsetInfoType_String: POffsetInfoType
         public override bool HasRelation() { return false; }
         public override bool Is1Dim() { return false; }
         public override bool IsMDim() { return false; }
+        // Some firmware versions swap UnspecifiedOffsetinfo1/2, so take the smaller value as the max. string length.
+        public override int MaxStringLength() { return Math.Min(UnspecifiedOffsetinfo1, UnspecifiedOffsetinfo2); }
 
         public static POffsetInfoType_String Deserialize(Stream buffer, out int length)
         {

src/S7CommPlusDriver/OpenSSL/OpenSSLConnector.cs

@@ -33,6 +33,8 @@ public class OpenSSLConnector : IDisposable
         private readonly byte[] m_buffer = new byte[4096];
         private readonly DataBufferList m_pendingWriteList;
         private readonly DataBufferList m_pendingReadList;
+        private readonly object m_readListLock = new object();
+        private readonly object m_writeListLock = new object();
         private bool m_fatalError;
         private bool m_disposed;
 
@@ -277,8 +279,16 @@ protected void RunSSL()
 
             while (!m_fatalError && ((!m_readRequired && dataToWrite) || dataToRead))
             {
-                int pendingReadBefore = m_pendingReadList.Count;
-                int pendingWriteBefore = m_pendingWriteList.Count;
+                int pendingReadBefore;
+                int pendingWriteBefore;
+                lock (m_readListLock)
+                {
+                    pendingReadBefore = m_pendingReadList.Count;
+                }
+                lock (m_writeListLock)
+                {
+                    pendingWriteBefore = m_pendingWriteList.Count;
+                }
                 bool readRequiredBefore = m_readRequired;
                 var bioPendingBefore = Native.BIO_ctrl_pending(m_pBioOut);
 
@@ -304,8 +314,18 @@ protected void RunSSL()
 
                 GetPendingOperations(ref dataToRead, ref dataToWrite);
                 var bioPendingAfter = Native.BIO_ctrl_pending(m_pBioOut);
-                if (pendingReadBefore == m_pendingReadList.Count &&
-                    pendingWriteBefore == m_pendingWriteList.Count &&
+                int pendingReadAfter;
+                int pendingWriteAfter;
+                lock (m_readListLock)
+                {
+                    pendingReadAfter = m_pendingReadList.Count;
+                }
+                lock (m_writeListLock)
+                {
+                    pendingWriteAfter = m_pendingWriteList.Count;
+                }
+                if (pendingReadBefore == pendingReadAfter &&
+                    pendingWriteBefore == pendingWriteAfter &&
                     readRequiredBefore == m_readRequired &&
                     bioPendingBefore == bioPendingAfter)
                 {
@@ -341,8 +361,14 @@ public void ReadCompleted(byte[] pData, int dataLen)
 
         private void GetPendingOperations(ref bool dataToRead, ref bool dataToWrite)
         {
-            dataToRead = m_pendingReadList.Count > 0;
-            dataToWrite = m_pendingWriteList.Count > 0;
+            lock (m_readListLock)
+            {
+                dataToRead = m_pendingReadList.Count > 0;
+            }
+            lock (m_writeListLock)
+            {
+                dataToWrite = m_pendingWriteList.Count > 0;
+            }
         }
 
         private void PerformRead()
@@ -437,23 +463,35 @@ private void UseData(DataBufferList list, DataBuffer pBuffer, int result)
 
         private void AppendBuffer(DataBufferList list, DataBuffer pBuffer)
         {
-            list.AddLast(pBuffer);
+            object lockObject = (list == m_pendingReadList) ? m_readListLock : m_writeListLock;
+            lock (lockObject)
+            {
+                list.AddLast(pBuffer);
+            }
         }
 
         DataBuffer GetNextBuffer(DataBufferList list)
         {
             DataBuffer head = null;
-            if (list.Count > 0)
+            object lockObject = (list == m_pendingReadList) ? m_readListLock : m_writeListLock;
+            lock (lockObject)
             {
-                head = list.First.Value;
-                list.RemoveFirst();
+                if (list.Count > 0)
+                {
+                    head = list.First.Value;
+                    list.RemoveFirst();
+                }
             }
             return head;
         }
 
         void PutbackBuffer(DataBufferList list, DataBuffer pBuffer)
         {
-            list.AddFirst(pBuffer);
+            object lockObject = (list == m_pendingReadList) ? m_readListLock : m_writeListLock;
+            lock (lockObject)
+            {
+                list.AddFirst(pBuffer);
+            }
         }
 
         /// <summary>