Modbus Coil/DI array fix, support for Word Swap

plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/optimizer/ModbusOptimizer.java

@@ -51,6 +51,7 @@
 import org.apache.plc4x.java.spi.messages.utils.PlcTagItem;
 import org.apache.plc4x.java.spi.optimizer.SingleTagOptimizer;
 import org.apache.plc4x.java.spi.values.PlcBOOL;
+import org.apache.plc4x.java.spi.values.PlcList;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -208,11 +209,25 @@ protected PlcReadResponse processReadResponses(PlcReadRequest readRequest, Map<P
 
                             // Calculate the byte that contains the response for this Coil
                             byte[] responseData = response.getResponseData();
-                            int bitPosition = modbusTag.getAddress() - response.startingAddress;
-                            int bytePosition = bitPosition / 8;
-                            int bitPositionInByte = bitPosition % 8;
-                            boolean isBitSet = (responseData[bytePosition] & (1 << bitPositionInByte)) != 0;
-                            values.put(tagName, new DefaultPlcResponseItem<>(PlcResponseCode.OK, new PlcBOOL(isBitSet)));
+
+                            // Check if we're dealing with an array of Coils or Discrete Inputs
+                            if (modbusTag.getNumberOfElements() > 1) {
+                                PlcList bitValues = new PlcList();
+                                for (int i = 0; i < modbusTag.getNumberOfElements(); i++) {
+                                    int bitPosition = modbusTag.getAddress() - response.startingAddress + i;
+                                    int bytePosition = bitPosition / 8;
+                                    int bitPositionInByte = bitPosition % 8;
+                                    boolean isBitSet = (responseData[bytePosition] & (1 << bitPositionInByte)) != 0;
+                                    bitValues.add(new PlcBOOL(isBitSet));
+                                }
+                                values.put(tagName, new DefaultPlcResponseItem<>(PlcResponseCode.OK, bitValues));
+                            } else {
+                                int bitPosition = modbusTag.getAddress() - response.startingAddress;
+                                int bytePosition = bitPosition / 8;
+                                int bitPositionInByte = bitPosition % 8;
+                                boolean isBitSet = (responseData[bytePosition] & (1 << bitPositionInByte)) != 0;
+                                values.put(tagName, new DefaultPlcResponseItem<>(PlcResponseCode.OK, new PlcBOOL(isBitSet)));
+                            }
                             break;
                         }
                     }
@@ -436,6 +451,32 @@ private ReadBuffer getReadBuffer(byte[] data, ModbusByteOrder byteOrder) {
                 byte[] reordered = ModbusProtocolLogic.byteSwap(data);
                 return new ReadBufferByteBased(reordered, ByteOrder.LITTLE_ENDIAN);
             }
+            case BIG_ENDIAN_WORD_SWAP: {
+                // [3, 4, 1, 2]
+                // [3, 4, 1, 2, 7, 8, 5, 6]
+                byte[] reordered = ModbusProtocolLogic.wordSwap(data);
+                return new ReadBufferByteBased(reordered, ByteOrder.BIG_ENDIAN);
+            }
+            case LITTLE_ENDIAN_WORD_SWAP: {
+                // [2, 1, 4, 3]
+                // [6, 5, 8, 7, 2, 1, 4, 3]
+                byte[] reordered = ModbusProtocolLogic.wordSwap(data);
+                return new ReadBufferByteBased(reordered, ByteOrder.LITTLE_ENDIAN);
+            }
+            case BIG_ENDIAN_WORD_SWAP_BYTE_SWAP: {
+                // [4, 3, 2, 1]
+                // [4, 3, 2, 1, 8, 7, 6, 5]
+                byte[] reordered = ModbusProtocolLogic.byteSwap(data);
+                reordered = ModbusProtocolLogic.wordSwap(reordered);
+                return new ReadBufferByteBased(reordered, ByteOrder.BIG_ENDIAN);
+            }
+            case LITTLE_ENDIAN_WORD_SWAP_BYTE_SWAP: {
+                // [1, 2, 3, 4]
+                // [5, 6, 7, 8, 1, 2, 3, 4]
+                byte[] reordered = ModbusProtocolLogic.byteSwap(data);
+                reordered = ModbusProtocolLogic.wordSwap(reordered);
+                return new ReadBufferByteBased(reordered, ByteOrder.LITTLE_ENDIAN);
+            }
             default:
                 // 16909060
                 // [1, 2, 3, 4]

plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/protocol/ModbusProtocolLogic.java

@@ -418,4 +418,18 @@ public static byte[] byteSwap(byte[] in) {
         return out;
     }
 
+    public static byte[] wordSwap(byte[] in) {
+        if (in.length % 2 != 0) {
+            throw new PlcRuntimeException("Input byte array length must be a multiple of 2 for word swapping.");
+        }
+        byte[] out = new byte[in.length];
+        for (int i = 0; i < in.length; i += 4) {
+            out[i] = in[i + 2];
+            out[i + 1] = in[i + 3];
+            out[i + 2] = in[i];
+            out[i + 3] = in[i + 1];
+        }
+        return out;
+    }
+
 }

plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/types/ModbusByteOrder.java

@@ -30,5 +30,17 @@ public enum ModbusByteOrder {
     BIG_ENDIAN_BYTE_SWAP,
     // [3, 4, 1, 2]
     // [7, 8, 5, 6, 3, 4, 1, 2]
-    LITTLE_ENDIAN_BYTE_SWAP
+    LITTLE_ENDIAN_BYTE_SWAP,
+    // [3, 4, 1, 2]
+    // [3, 4, 1, 2, 7, 8, 5, 6]
+    BIG_ENDIAN_WORD_SWAP,
+    // [2, 1, 4, 3]
+    // [6, 5, 8, 7, 2, 1, 4, 3]
+    LITTLE_ENDIAN_WORD_SWAP,
+    // [4, 3, 2, 1]
+    // [4, 3, 2, 1, 8, 7, 6, 5]
+    BIG_ENDIAN_WORD_SWAP_BYTE_SWAP,
+    // [1, 2, 3, 4]
+    // [5, 6, 7, 8, 1, 2, 3, 4]
+    LITTLE_ENDIAN_WORD_SWAP_BYTE_SWAP,
 }