Merge pull request #212 from Arneball/reuseempty

Reuse same instance of byte array when the destination array is empty

usbserial/src/main/java/com/felhr/usbserial/FTDISerialDevice.java

@@ -63,6 +63,7 @@ public class FTDISerialDevice extends UsbSerialDevice
     private static final int FTDI_SET_MODEM_CTRL_DEFAULT3 = 0x0100;
     private static final int FTDI_SET_MODEM_CTRL_DEFAULT4 = 0x0200;
     private static final int FTDI_SET_FLOW_CTRL_DEFAULT = 0x0000;
+    private static final byte[] EMPTY_BYTE_ARRAY = {};
 
     private int currentSioSetData = 0x0000;
 
@@ -140,8 +141,8 @@ public class FTDISerialDevice extends UsbSerialDevice
     @Override
     public void close()
     {
-        setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT3, 0, null);
+        setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT3, 0);
-        setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT4, 0, null);
+        setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT4, 0);
         currentSioSetData = 0x0000;
         killWorkingThread();
         killWriteThread();
@@ -175,8 +176,8 @@ public class FTDISerialDevice extends UsbSerialDevice
     @Override
     public void syncClose()
     {
-        setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT3, 0, null);
+        setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT3, 0);
-        setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT4, 0, null);
+        setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT4, 0);
         currentSioSetData = 0x0000;
         connection.releaseInterface(mInterface);
         isOpen = false;
@@ -216,7 +217,7 @@ public class FTDISerialDevice extends UsbSerialDevice
             value = FTDI_BAUDRATE_921600;
         else
             value = FTDI_BAUDRATE_9600;
-        setControlCommand(FTDI_SIO_SET_BAUD_RATE, value, 0, null);
+        setControlCommand(FTDI_SIO_SET_BAUD_RATE, value, 0);
     }
 
     @Override
@@ -229,35 +230,35 @@ public class FTDISerialDevice extends UsbSerialDevice
                 currentSioSetData &= ~(1 << 1);
                 currentSioSetData |= (1 << 2);
                 currentSioSetData &= ~(1 << 3);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             case UsbSerialInterface.DATA_BITS_6:
                 currentSioSetData &= ~1;
                 currentSioSetData |= (1 << 1);
                 currentSioSetData |= (1 << 2);
                 currentSioSetData &= ~(1 << 3);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             case UsbSerialInterface.DATA_BITS_7:
                 currentSioSetData |= 1;
                 currentSioSetData |= (1 << 1);
                 currentSioSetData |= (1 << 2);
                 currentSioSetData &= ~(1 << 3);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             case UsbSerialInterface.DATA_BITS_8:
                 currentSioSetData &= ~1;
                 currentSioSetData &= ~(1 << 1);
                 currentSioSetData &= ~(1 << 2);
                 currentSioSetData |= (1 << 3);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             default:
                 currentSioSetData &= ~1;
                 currentSioSetData &= ~(1 << 1);
                 currentSioSetData &= ~(1 << 2);
                 currentSioSetData |= (1 << 3);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
         }
 
@@ -272,25 +273,25 @@ public class FTDISerialDevice extends UsbSerialDevice
                 currentSioSetData &= ~(1 << 11);
                 currentSioSetData &= ~(1 << 12);
                 currentSioSetData &= ~(1 << 13);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             case UsbSerialInterface.STOP_BITS_15:
                 currentSioSetData |= (1 << 11);
                 currentSioSetData &= ~(1 << 12);
                 currentSioSetData &= ~(1 << 13);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             case UsbSerialInterface.STOP_BITS_2:
                 currentSioSetData &= ~(1 << 11);
                 currentSioSetData |= (1 << 12);
                 currentSioSetData &= ~(1 << 13);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             default:
                 currentSioSetData &= ~(1 << 11);
                 currentSioSetData &= ~(1 << 12);
                 currentSioSetData &= ~(1 << 13);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
         }
 
     }
@@ -304,37 +305,37 @@ public class FTDISerialDevice extends UsbSerialDevice
                 currentSioSetData &= ~(1 << 8);
                 currentSioSetData &= ~(1 << 9);
                 currentSioSetData &= ~(1 << 10);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             case UsbSerialInterface.PARITY_ODD:
                 currentSioSetData |= (1 << 8);
                 currentSioSetData &= ~(1 << 9);
                 currentSioSetData &= ~(1 << 10);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             case UsbSerialInterface.PARITY_EVEN:
                 currentSioSetData &= ~(1 << 8);
                 currentSioSetData |= (1 << 9);
                 currentSioSetData &= ~(1 << 10);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             case UsbSerialInterface.PARITY_MARK:
                 currentSioSetData |= (1 << 8);
                 currentSioSetData |= (1 << 9);
                 currentSioSetData &= ~(1 << 10);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             case UsbSerialInterface.PARITY_SPACE:
                 currentSioSetData &= ~(1 << 8);
                 currentSioSetData &= ~(1 << 9);
                 currentSioSetData |= (1 << 10);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
             default:
                 currentSioSetData &= ~(1 << 8);
                 currentSioSetData &= ~(1 << 9);
                 currentSioSetData &= ~(1 << 10);
-                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0, null);
+                setControlCommand(FTDI_SIO_SET_DATA, currentSioSetData, 0);
                 break;
         }
 
@@ -346,7 +347,7 @@ public class FTDISerialDevice extends UsbSerialDevice
         switch(flowControl)
         {
             case UsbSerialInterface.FLOW_CONTROL_OFF:
-                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, 0, null);
+                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, 0);
                 rtsCtsEnabled = false;
                 dtrDsrEnabled = false;
                 break;
@@ -354,21 +355,21 @@ public class FTDISerialDevice extends UsbSerialDevice
                 rtsCtsEnabled = true;
                 dtrDsrEnabled = false;
                 int indexRTSCTS = 0x0001;
-                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, indexRTSCTS, null);
+                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, indexRTSCTS);
                 break;
             case UsbSerialInterface.FLOW_CONTROL_DSR_DTR:
                 dtrDsrEnabled = true;
                 rtsCtsEnabled = false;
                 int indexDSRDTR = 0x0002;
-                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, indexDSRDTR , null);
+                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, indexDSRDTR);
                 break;
             case UsbSerialInterface.FLOW_CONTROL_XON_XOFF:
                 int indexXONXOFF = 0x0004;
                 int wValue = 0x1311;
-                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, wValue, indexXONXOFF , null);
+                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, wValue, indexXONXOFF);
                 break;
             default:
-                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, 0, null);
+                setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, 0);
                 break;
         }
     }
@@ -378,10 +379,10 @@ public class FTDISerialDevice extends UsbSerialDevice
     {
         if(state)
         {
-            setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SIO_SET_RTS_HIGH, 0, null);
+            setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SIO_SET_RTS_HIGH, 0);
         }else
         {
-            setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SIO_SET_RTS_LOW, 0, null);
+            setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SIO_SET_RTS_LOW, 0);
         }
     }
 
@@ -390,10 +391,10 @@ public class FTDISerialDevice extends UsbSerialDevice
     {
         if(state)
         {
-            setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SIO_SET_DTR_HIGH, 0, null);
+            setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SIO_SET_DTR_HIGH, 0);
         }else
         {
-            setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SIO_SET_DTR_LOW, 0, null);
+            setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SIO_SET_DTR_LOW, 0);
         }
     }
 
@@ -461,18 +462,18 @@ public class FTDISerialDevice extends UsbSerialDevice
 
         // Default Setup
         firstTime = true;
-        if(setControlCommand(FTDI_SIO_RESET, 0x00, 0, null) < 0)
+        if(setControlCommand(FTDI_SIO_RESET, 0x00, 0) < 0)
             return false;
-        if(setControlCommand(FTDI_SIO_SET_DATA, FTDI_SET_DATA_DEFAULT, 0, null) < 0)
+        if(setControlCommand(FTDI_SIO_SET_DATA, FTDI_SET_DATA_DEFAULT, 0) < 0)
             return false;
         currentSioSetData = FTDI_SET_DATA_DEFAULT;
-        if(setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT1, 0, null) < 0)
+        if(setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT1, 0) < 0)
             return false;
-        if(setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT2, 0, null) < 0)
+        if(setControlCommand(FTDI_SIO_MODEM_CTRL, FTDI_SET_MODEM_CTRL_DEFAULT2, 0) < 0)
             return false;
-        if(setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, 0, null) < 0)
+        if(setControlCommand(FTDI_SIO_SET_FLOW_CTRL, FTDI_SET_FLOW_CTRL_DEFAULT, 0) < 0)
             return false;
-        if(setControlCommand(FTDI_SIO_SET_BAUD_RATE, FTDI_BAUDRATE_9600, 0, null) < 0)
+        if(setControlCommand(FTDI_SIO_SET_BAUD_RATE, FTDI_BAUDRATE_9600, 0) < 0)
             return false;
 
         // Flow control disabled by default
@@ -482,44 +483,62 @@ public class FTDISerialDevice extends UsbSerialDevice
         return true;
     }
 
-    private int setControlCommand(int request, int value, int index, byte[] data)
+    private int setControlCommand(int request, int value, int index)
     {
         int dataLength = 0;
-        if(data != null)
+        int response = connection.controlTransfer(FTDI_REQTYPE_HOST2DEVICE, request, value, mInterface.getId() + 1 + index, null, dataLength, USB_TIMEOUT);
-        {
-            dataLength = data.length;
-        }
-        int response = connection.controlTransfer(FTDI_REQTYPE_HOST2DEVICE, request, value, mInterface.getId() + 1 + index, data, dataLength, USB_TIMEOUT);
         Log.i(CLASS_ID,"Control Transfer Response: " + String.valueOf(response));
         return response;
     }
 
+    // Special treatment needed to FTDI devices
+    static byte[] adaptArray(byte[] ftdiData)
+    {
+        int length = ftdiData.length;
+        if(length > 64)
+        {
+            int n = 1;
+            int p = 64;
+            // Precalculate length without FTDI headers
+            while(p < length)
+            {
+                n++;
+                p = n*64;
+            }
+            int realLength = length - n*2;
+            byte[] data = new byte[realLength];
+            copyData(ftdiData, data);
+            return data;
+        }
+        else if (length == 2) // special case optimization that returns the same instance.
+        {
+            return EMPTY_BYTE_ARRAY;
+        }
+        else
+        {
+            return Arrays.copyOfRange(ftdiData, 2, length);
+        }
+    }
+
+    // Copy data without FTDI headers
+    private static void copyData(byte[] src, byte[] dst)
+    {
+        int srcPos = 2, dstPos = 0;
+        while(srcPos - 2 <= src.length - 64)
+        {
+            System.arraycopy(src, srcPos, dst, dstPos, 62);
+            srcPos += 64;
+            dstPos += 62;
+        }
+        int remaining = src.length - srcPos + 2;
+        if (remaining > 0)
+        {
+            System.arraycopy(src, srcPos, dst, dstPos, remaining - 2);
+        }
+    }
+
     public class FTDIUtilities
     {
-        // Special treatment needed to FTDI devices
-        public byte[] adaptArray(byte[] ftdiData)
-        {
-            int length = ftdiData.length;
-            if(length > 64)
-            {
-                int n = 1;
-                int p = 64;
-                // Precalculate length without FTDI headers
-                while(p < length)
-                {
-                    n++;
-                    p = n*64;
-                }
-                int realLength = length - n*2;
-                byte[] data = new byte[realLength];
-                copyData(ftdiData, data);
-                return data;
-            }else
-            {
-                return Arrays.copyOfRange(ftdiData, 2, length);
-            }
-        }
-
         public void checkModemStatus(byte[] data)
         {
             if(data.length == 0) // Safeguard for zero length arrays
@@ -589,31 +608,6 @@ public class FTDISerialDevice extends UsbSerialDevice
                 }
             }
         }
-
-        // Copy data without FTDI headers
-        private void copyData(byte[] src, byte[] dst)
-        {
-            int i = 0; // src index
-            int j = 0; // dst index
-            while(i <= src.length-1)
-            {
-                if(i != 0 && i != 1)
-                {
-                    if(i % 64 == 0 && i >= 64)
-                    {
-                        i += 2;
-                    }else
-                    {
-                        dst[j] = src[i];
-                        i++;
-                        j++;
-                    }
-                }else
-                {
-                    i++;
-                }
-            }
-        }
     }
 
     @Override
@@ -658,7 +652,7 @@ public class FTDISerialDevice extends UsbSerialDevice
 
             if(numberBytes > 2) // Data received
             {
-                byte[] newBuffer = this.ftdiUtilities.adaptArray(tempBuffer);
+                byte[] newBuffer = adaptArray(tempBuffer);
                 System.arraycopy(newBuffer, 0, buffer, 0, buffer.length);
 
                 int p = numberBytes / 64;

usbserial/src/main/java/com/felhr/usbserial/UsbSerialDevice.java

@@ -331,7 +331,7 @@ public abstract class UsbSerialDevice implements UsbSerialInterface
 
                     if(data.length > 2)
                     {
-                        data = ((FTDISerialDevice) usbSerialDevice).ftdiUtilities.adaptArray(data);
+                        data = FTDISerialDevice.adaptArray(data);
                         onReceivedData(data);
                     }
                 }else
@@ -425,7 +425,7 @@ public abstract class UsbSerialDevice implements UsbSerialInterface
 
                     if(dataReceived.length > 2)
                     {
-                        dataReceived = ((FTDISerialDevice) usbSerialDevice).ftdiUtilities.adaptArray(dataReceived);
+                        dataReceived = FTDISerialDevice.adaptArray(dataReceived);
                         onReceivedData(dataReceived);
                     }
                 }else

usbserial/src/test/java/com/felhr/usbserial/FTDISerialDeviceTest.java

@@ -0,0 +1,49 @@
+package com.felhr.usbserial;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import java.util.Arrays;
+
+@RunWith(JUnit4.class)
+public class FTDISerialDeviceTest {
+
+    @Test
+    public void adaptEmptyByteArray() {
+        byte[] onlyHeaders = {1, 2};
+        byte[] adapted = FTDISerialDevice.adaptArray(onlyHeaders);
+        Assert.assertEquals("Should be empty", 0, adapted.length);
+        byte[] adaptAgain = FTDISerialDevice.adaptArray(onlyHeaders);
+        Assert.assertSame("Should be the same instance of empty array", adapted, adaptAgain);
+    }
+
+    @Test
+    public void withHeaders() {
+        byte[] withHeaders = {1, 2, 3, 4, 5, 6};
+        byte[] wanted = {3,4,5,6};
+        Assert.assertArrayEquals(wanted, FTDISerialDevice.adaptArray(withHeaders));
+    }
+
+    @Test
+    public void fullWithHeaders() {
+        byte[] withHeaders = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64};
+        byte[] wanted = Arrays.copyOfRange(withHeaders, 2, 64);
+        Assert.assertArrayEquals(wanted, FTDISerialDevice.adaptArray(withHeaders));
+    }
+
+    @Test
+    public void testMultipleFull() {
+        byte[] withHeaders = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64, 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64};
+        byte[] wanted = {3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64, 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64};
+        Assert.assertArrayEquals(wanted, FTDISerialDevice.adaptArray(withHeaders));
+    }
+
+    @Test
+    public void testMultiplePartial() {
+        byte[] withHeaders = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64, 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62};
+        byte[] wanted = {3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64, 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62};
+        Assert.assertArrayEquals(wanted, FTDISerialDevice.adaptArray(withHeaders));
+    }
+}