Update Cp21xxSerialDriver.cs

Author: IhorNehrutsa

UsbSerialForAndroid/driver/Cp21xxSerialDriver.cs

@@ -57,11 +57,11 @@ public class Cp21xxSerialPort : CommonUsbSerialPort
             private const int FLUSH_READ_CODE = 0x0a;
             private const int FLUSH_WRITE_CODE = 0x05;
 
-            private static int GET_MODEM_STATUS_REQUEST = 0x08; // 0x08 Get modem status. 
-            private static int MODEM_STATUS_CTS = 0x10;
-            private static int MODEM_STATUS_DSR = 0x20;
-            private static int MODEM_STATUS_RI = 0x40;
-            private static int MODEM_STATUS_CD = 0x80;
+            private const int GET_MODEM_STATUS_REQUEST = 0x08; // 0x08 Get modem status. 
+            private const int MODEM_STATUS_CTS = 0x10;
+            private const int MODEM_STATUS_DSR = 0x20;
+            private const int MODEM_STATUS_RI = 0x40;
+            private const int MODEM_STATUS_CD = 0x80;
             /*
              * SILABSER_IFC_ENABLE_REQUEST_CODE
              */
@@ -86,7 +86,7 @@ public class Cp21xxSerialPort : CommonUsbSerialPort
             private UsbEndpoint mReadEndpoint;
             private UsbEndpoint mWriteEndpoint;
 
-            private IUsbSerialDriver Driver;
+            private new IUsbSerialDriver Driver;
             private string TAG => (Driver as Cp21xxSerialDriver)?.TAG;
 
 
@@ -210,28 +210,16 @@ public override int Read(byte[] dest, int timeoutMillis)
             public override int Write(byte[] src, int timeoutMillis)
             {
                 int offset = 0;
+                int writeLength;
+                int amtWritten;
 
                 while (offset < src.Length)
                 {
-                    int writeLength;
-                    int amtWritten;
-
                     lock(mWriteBufferLock) {
-                        byte[] writeBuffer;
 
-                        writeLength = Math.Min(src.Length - offset, mWriteBuffer.Length);
-                        if (offset == 0)
-                        {
-                            writeBuffer = src;
-                        }
-                        else
-                        {
-                            // bulkTransfer does not support offsets, make a copy.
-                            Buffer.BlockCopy(src, offset, mWriteBuffer, 0, writeLength);
-                            writeBuffer = mWriteBuffer;
-                        }
+                        writeLength = src.Length - offset;
 
-                        amtWritten = mConnection.BulkTransfer(mWriteEndpoint, writeBuffer, writeLength,
+                        amtWritten = mConnection.BulkTransfer(mWriteEndpoint, src, offset, writeLength,
                                 timeoutMillis);
                     }
                     if (amtWritten <= 0)