Merge DIYglenn

Arduino Code/Arduino Libraries/HanReader/src/DlmsReader.cpp

@@ -0,0 +1,154 @@
+#include "DlmsReader.h"
+
+DlmsReader::DlmsReader()
+{
+    //this->Clear();
+}
+
+void DlmsReader::Clear()
+{
+    this->position = 0;
+    this->dataLength = 0;
+    this->destinationAddressLength = 0;
+    this->sourceAddressLength = 0;
+    this->frameFormatType = 0;
+}
+
+bool DlmsReader::Read(byte data)
+{
+    if (position == 0 && data != 0x7E)
+    {
+        // we haven't started yet, wait for the start flag (no need to capture any data yet)
+        return false;
+    }
+    else
+    {
+        // We have completed reading of one package, so clear and be ready for the next
+        if (dataLength > 0 && position >= dataLength + 2)
+            Clear();
+        
+        // Check if we're about to run into a buffer overflow
+        if (position >= DLMS_READER_BUFFER_SIZE)
+            Clear();
+
+        // Check if this is a second start flag, which indicates the previous one was a stop from the last package
+        if (position == 1 && data == 0x7E)
+        {
+            // just return, we can keep the one byte we had in the buffer
+            return false;
+        }
+
+        // We have started, so capture every byte
+        buffer[position++] = data;
+
+        if (position == 1)
+        {
+            // This was the start flag, we're not done yet
+            return false;
+        }
+        else if (position == 2)
+        {
+            // Capture the Frame Format Type
+            frameFormatType = (byte)(data & 0xF0);
+            if (!IsValidFrameFormat(frameFormatType))
+                Clear();
+            return false;
+        }
+        else if (position == 3)
+        {
+            // Capture the length of the data package
+            dataLength = ((buffer[1] & 0x0F) << 8) | buffer[2];
+            return false;
+        }
+        else if (destinationAddressLength == 0)
+        {
+            // Capture the destination address
+            destinationAddressLength = GetAddress(3, destinationAddress, 0, DLMS_READER_MAX_ADDRESS_SIZE);
+            if (destinationAddressLength > 3)
+                Clear();
+            return false;
+        }
+        else if (sourceAddressLength == 0)
+        {
+            // Capture the source address
+            sourceAddressLength = GetAddress(3 + destinationAddressLength, sourceAddress, 0, DLMS_READER_MAX_ADDRESS_SIZE);
+            if (sourceAddressLength > 3)
+                Clear();
+            return false;
+        }
+        else if (position == 4 + destinationAddressLength + sourceAddressLength + 2)
+        {
+            // Verify the header checksum
+            ushort headerChecksum = GetChecksum(position - 3);
+            if (headerChecksum != Crc16.ComputeChecksum(buffer, 1, position - 3))
+                Clear();
+            return false;
+        }
+        else if (position == dataLength + 1)
+        {
+            // Verify the data package checksum
+            ushort checksum = this->GetChecksum(position - 3);
+            if (checksum != Crc16.ComputeChecksum(buffer, 1, position - 3))
+                Clear();
+            return false;
+        }
+        else if (position == dataLength + 2)
+        {
+            // We're done, check the stop flag and signal we're done
+            if (data == 0x7E)
+                return true;
+            else
+            {
+                Clear();
+                return false;
+            }
+        }
+    }
+    return false;
+}
+
+bool DlmsReader::IsValidFrameFormat(byte frameFormatType)
+{
+    return frameFormatType == 0xA0;
+}
+
+int DlmsReader::GetRawData(byte *dataBuffer, int start, int length)
+{
+    if (dataLength > 0 && position == dataLength + 2)
+    {
+        int headerLength = 3 + destinationAddressLength + sourceAddressLength + 2;
+        int bytesWritten = 0;
+        for (int i = headerLength + 1; i < dataLength - 1; i++)
+        {
+          dataBuffer[i + start - headerLength - 1] = buffer[i];
+          bytesWritten++;
+        }
+        return bytesWritten;
+    }
+    else
+        return 0;
+}
+
+int DlmsReader::GetAddress(int addressPosition, byte* addressBuffer, int start, int length)
+{
+    int addressBufferPos = start;
+    for (int i = addressPosition; i < position; i++)
+    {
+        addressBuffer[addressBufferPos++] = buffer[i];
+        
+        // LSB=1 means this was the last address byte
+        if ((buffer[i] & 0x01) == 0x01)  
+            break;
+
+        // See if we've reached last byte, try again when we've got more data
+        else if (i == position - 1)
+            return 0;
+    }
+    return addressBufferPos - start;
+}
+
+ushort DlmsReader::GetChecksum(int checksumPosition)
+{
+    return (ushort)(buffer[checksumPosition + 2] << 8 |
+        buffer[checksumPosition + 1]);
+}