transferOut() with offset and length

Author: manuelbl

java-does-usb/src/main/java/net/codecrete/usb/USBDevice.java

@@ -293,11 +293,34 @@ public interface USBDevice {
      * </p>
      *
      * @param endpointNumber the endpoint number (in the range between 1 and 127)
-     * @param timeout        the timeout period, in milliseconds (0 for no timeout)
      * @param data           data to send
+     * @param timeout        the timeout period, in milliseconds (0 for no timeout)
      */
     void transferOut(int endpointNumber, byte[] data, int timeout);
 
+    /**
+     * Sends data to this device.
+     * <p>
+     * This method blocks until the data has been sent, the timeout period has expired
+     * or an error has occurred. If the timeout expires, a {@link USBTimeoutException} is thrown.
+     * </p>
+     * <p>
+     * This method can send data to bulk and interrupt endpoints.
+     * </p>
+     * <p>
+     * If the sent data length is a multiple of the packet size, it is often
+     * required to send an additional zero-length packet (ZLP) for the device
+     * to actually process the data. This method will not do it automatically.
+     * </p>
+     *
+     * @param endpointNumber the endpoint number (in the range between 1 and 127)
+     * @param data           buffer containing data to send
+     * @param offset         offset of the first byte to send
+     * @param length         number of bytes to send
+     * @param timeout        the timeout period, in milliseconds (0 for no timeout)
+     */
+    void transferOut(int endpointNumber, byte[] data, int offset, int length, int timeout);
+
     /**
      * Receives data from this device.
      * <p>

java-does-usb/src/main/java/net/codecrete/usb/common/USBDeviceImpl.java

@@ -320,11 +320,16 @@ protected int getInterfaceNumber(USBDirection direction, int endpointNumber) {
 
     @Override
     public void transferOut(int endpointNumber, byte[] data) {
-        transferOut(endpointNumber, data, 0);
+        transferOut(endpointNumber, data, 0, data.length, 0);
     }
 
     @Override
-    public abstract void transferOut(int endpointNumber, byte[] data, int timeout);
+    public void transferOut(int endpointNumber, byte[] data, int timeout) {
+        transferOut(endpointNumber, data, 0, data.length, timeout);
+    }
+
+    @Override
+    public abstract void transferOut(int endpointNumber, byte[] data, int offset, int length, int timeout);
 
     @Override
     public byte[] transferIn(int endpointNumber) {

java-does-usb/src/main/java/net/codecrete/usb/linux/LinuxUSBDevice.java

@@ -271,10 +271,10 @@ private LinuxTransfer createSyncCtrlTransfer(Arena arena, USBDirection direction
     }
 
     @Override
-    public void transferOut(int endpointNumber, byte[] data, int timeout) {
+    public void transferOut(int endpointNumber, byte[] data, int offset, int length, int timeout) {
         try (var arena = Arena.openConfined()) {
-            var buffer = arena.allocate(data.length);
-            buffer.copyFrom(MemorySegment.ofArray(data));
+            var buffer = arena.allocate(length);
+            buffer.copyFrom(MemorySegment.ofArray(data).asSlice(offset, length));
             var transfer = createSyncTransfer(buffer);
 
             synchronized (transfer) {

java-does-usb/src/main/java/net/codecrete/usb/macos/MacosUSBDevice.java

@@ -412,18 +412,18 @@ public void controlTransferOut(USBControlTransfer setup, byte[] data) {
     }
 
     @Override
-    public void transferOut(int endpointNumber, byte[] data, int timeout) {
+    public void transferOut(int endpointNumber, byte[] data, int offset, int length, int timeout) {
 
         EndpointInfo epInfo = getEndpointInfo(endpointNumber, USBDirection.OUT, USBTransferType.BULK,
                 USBTransferType.INTERRUPT);
 
         try (var arena = Arena.openConfined()) {
-            var nativeData = arena.allocateArray(JAVA_BYTE, data.length);
-            nativeData.copyFrom(MemorySegment.ofArray(data));
+            var nativeData = arena.allocateArray(JAVA_BYTE, length);
+            nativeData.copyFrom(MemorySegment.ofArray(data).asSlice(offset, length));
 
             var transfer = new MacosTransfer();
             transfer.data = nativeData;
-            transfer.dataSize = data.length;
+            transfer.dataSize = length;
             transfer.completion = USBDeviceImpl::onSyncTransferCompleted;
 
             synchronized (transfer) {

java-does-usb/src/main/java/net/codecrete/usb/windows/WindowsUSBDevice.java

@@ -244,10 +244,10 @@ public byte[] controlTransferIn(USBControlTransfer setup, int length) {
     }
 
     @Override
-    public void transferOut(int endpointNumber, byte[] data, int timeout) {
+    public void transferOut(int endpointNumber, byte[] data, int offset, int length, int timeout) {
         try (var arena = Arena.openConfined()) {
             var buffer = arena.allocate(data.length);
-            buffer.copyFrom(MemorySegment.ofArray(data));
+            buffer.copyFrom(MemorySegment.ofArray(data).asSlice(offset, length));
             var transfer = createSyncTransfer(buffer);
 
             synchronized (transfer) {