Basic implementation for CRC processing which works with long/short f…

…rames.

Related to #59.

org.openhab.binding.wmbus.tools/src/main/java/org/openhab/binding/wmbus/tools/processor/SkipCrcProcessor.java

@@ -1,6 +1,6 @@
 /**
  * Copyright (c) 2010-2018 by the respective copyright holders.
- *
+ * <p>
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -10,30 +10,47 @@
 
 import org.openhab.binding.wmbus.tools.Processor;
 
+import java.util.HashMap;
 import java.util.Map;
 
 public class SkipCrcProcessor implements Processor<String> {
 
   @Override
   public String process(String frame, Map<String, Object> context) {
     String strippedframe = "";
+    int len = frame.length() / 2; // include all fields
+
+    //int lengthField = Integer.decode(frame.substring(0, 2));
+    int ciField = parseInt(frame, 22, 24);
+    boolean formatB = ciField == 0x72 || ciField == 0x7A;
+
+    if (formatB) {
+      strippedframe += frame.substring(0, Math.min(18, frame.length() - 4));
+      // block 1 + block 2 = 11 + ((16*n)+2) -- max 129 bytes
+      if (len <= 129) {
+        strippedframe += frame.substring(Math.min(22, frame.length()), frame.length() - 4);
+      }
+      // block 1 + block 2 + block 3= 11 + ((16*n)+2) + (16*n) -- bytes > 129
+      else {
+        strippedframe += frame.substring(22, 256);
+        strippedframe += frame.substring(Math.min(260, frame.length()), frame.length() - 4);
+      }
+    } else {
+      // assume that we starts counting from C-field
+      strippedframe += frame.substring(0, Math.min(18, frame.length()));
+      int position = 22;
+      while (position < frame.length()) {
+        strippedframe += frame.substring(position, Math.min(position + 32, frame.length()));
+        position += 36;
+      }
+      strippedframe = strippedframe.substring(0,strippedframe.length()-4);
+    }
 
-      strippedframe += frame.substring(Math.min(0, frame.length()), Math.min(18, frame.length()));
-      strippedframe += frame.substring(Math.min(22, frame.length()), Math.min(54, frame.length()));
-      strippedframe += frame.substring(Math.min(58, frame.length()), Math.min(90, frame.length()));
-
-    // String strippedframe = frame.substring(0, 18) + frame.substring(22, frame.length());
-    /*
-     * TODO: general implementation
-     *
-     *
-     * Integer position = 2;
-     * while (position < frame.length()) {
-     * strippedframe += frame.substring(position, position+16);
-     * position += 16 ;
-     * }
-     */
     return strippedframe;
   }
 
+  private int parseInt(String frame, int startIndex, int endIndex) {
+    return Integer.parseInt(frame.substring(startIndex, endIndex), 16);
+  }
+
 }

org.openhab.binding.wmbus.tools/src/test/java/org/openhab/binding/wmbus/tools/processor/SkipCrcProcessorTest.java

@@ -0,0 +1,40 @@
+package org.openhab.binding.wmbus.tools.processor;
+
+import java.util.HashMap;
+import java.util.Map;
+import junit.framework.TestCase;
+import org.junit.Test;
+
+public class SkipCrcProcessorTest extends TestCase {
+
+  SkipCrcProcessor stripCrc = new SkipCrcProcessor();
+  Map<String, Object> context = new HashMap<>();
+
+  @Test
+  public void testFrameFormatB() {
+    String input  = "11111111111111111100007A1111111111111111111111111111110000";
+    String output = "1111111111111111117A111111111111111111111111111111";
+    String result = stripCrc.process(input, context);
+
+    assertEquals(output, result);
+  }
+
+  @Test
+  public void testFrame1() {
+    String input  = "111111111111111111000011111111111111111111111111110000";
+    String output = "1111111111111111111111111111111111111111111111";
+    String result = stripCrc.process(input, context);
+
+    assertEquals(output, result);
+  }
+
+  @Test
+  public void testFrame3() {
+    String input  = "11111111111111111100001111111111111111111111111111111100001111111111110000";
+    String output = "11111111111111111111111111111111111111111111111111111111111111";
+    String result = stripCrc.process(input, context);
+
+    assertEquals(output, result);
+  }
+
+}