Additional debugging output.

Improve throughput of PollingInputStream by reducing the read buffer size.

android_acm_serial/src/org/ros/android/acm_serial/AcmInputStream.java

@@ -77,6 +77,7 @@ public class AcmInputStream extends InputStream {
     System.arraycopy(slice, 0, buffer, offset, byteCount);
     if (DEBUG) {
       Log.i(TAG, "Actually read " + byteCount + " bytes.");
+      Log.i(TAG, "Slice: " + byteArrayToHexString(slice));
     }
     return byteCount;
   }
@@ -85,4 +86,19 @@ public class AcmInputStream extends InputStream {
   public int read() throws IOException {
     throw new UnsupportedOperationException();
   }
+
+  // TODO(damonkohler): Possibly move this to some common place?
+  private static String byteArrayToHexString(byte[] data) {
+    if (data == null) {
+      return "null";
+    }
+    if (data.length == 0) {
+      return "empty";
+    }
+    StringBuilder out = new StringBuilder(data.length * 5);
+    for (byte b : data) {
+      out.append(String.format("%02x", b));
+    }
+    return out.toString();
+  }
 }

android_acm_serial/src/org/ros/android/acm_serial/PollingInputStream.java

@@ -29,7 +29,7 @@ import java.io.PipedOutputStream;
  */
 public class PollingInputStream extends InputStream {
 
-  private final static int STREAM_BUFFER_SIZE = 8192;
+  private final static int STREAM_BUFFER_SIZE = 256;
 
   private final PipedInputStream pipedInputStream;
 
@@ -45,7 +45,7 @@ public class PollingInputStream extends InputStream {
       public void run() {
         Process.setThreadPriority(Process.THREAD_PRIORITY_MORE_FAVORABLE);
         byte[] buffer = new byte[STREAM_BUFFER_SIZE];
-        while (true) {
+        while (true && !Thread.currentThread().isInterrupted()) {
           try {
             int bytesRead = inputStream.read(buffer, 0, STREAM_BUFFER_SIZE);
             pipedOutputStream.write(buffer, 0, bytesRead);