Work around USB error by using a BufferedInputStream.

android_acm_serial/src/org/ros/rosjava/android/acm_serial/AcmDevice.java

@@ -86,10 +86,6 @@ public class AcmDevice {
     return inputStream;
   }
 
-  public AcmReader getReader() {
-    return new AcmReader(usbDeviceConnection, incomingEndpoint);
-  }
-
   public OutputStream getOutputStream() {
     return outputStream;
   }

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

@@ -27,7 +27,9 @@ import java.io.InputStream;
 
 public class AcmInputStream extends InputStream {
 
-  private static final int TIMEOUT = 3000;
+  // Disable USB read timeouts. Reads are expected to block until data becomes
+  // available.
+  private static final int TIMEOUT = 0;
 
   private final UsbDeviceConnection connection;
   private final UsbEndpoint endpoint;

android_acm_serial/src/org/ros/rosjava/android/acm_serial/AcmReader.java

@@ -1,38 +0,0 @@
-package org.ros.rosjava.android.acm_serial;
-
-import android.hardware.usb.UsbDeviceConnection;
-import android.hardware.usb.UsbEndpoint;
-
-import java.io.IOException;
-import java.io.Reader;
-import java.nio.charset.Charset;
-
-public class AcmReader extends Reader {
-
-  private static final int TIMEOUT = 3000;
-
-  private final UsbDeviceConnection connection;
-  private final UsbEndpoint endpoint;
-
-  public AcmReader(UsbDeviceConnection connection, UsbEndpoint endpoint) {
-    this.connection = connection;
-    this.endpoint = endpoint;
-  }
-
-  @Override
-  public int read(char[] buf, int offset, int count) throws IOException {
-    byte[] buffer = new byte[count];
-    int byteCount = connection.bulkTransfer(endpoint, buffer, buffer.length, TIMEOUT);
-    if (byteCount < 0) {
-      throw new IOException();
-    }
-    char[] charBuffer = new String(buffer, Charset.forName("US-ASCII")).toCharArray();
-    System.arraycopy(charBuffer, 0, buf, offset, byteCount);
-    return byteCount;
-  }
-
-  @Override
-  public void close() throws IOException {
-  }
-
-}

android_hokuyo/src/org/ros/rosjava/android/hokuyo/Scip20Device.java

@@ -22,9 +22,12 @@ import android.util.Log;
 import org.ros.exception.RosRuntimeException;
 import org.ros.rosjava.android.acm_serial.AcmDevice;
 
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.IOException;
+import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.nio.charset.Charset;
 
@@ -33,17 +36,22 @@ public class Scip20Device {
   private static final boolean DEBUG = true;
   private static final String TAG = "Scip20Device";
 
+  private static final int STREAM_BUFFER_SIZE = 8192;
+
   private final BufferedReader reader;
   private final BufferedWriter writer;
 
   public Scip20Device(AcmDevice device) {
     // TODO(damonkohler): Wrapping the AcmDevice InputStream in an
-    // InputStreamReader crashes after a few scans. The AcmReader doesn't have
-    // this problem.
-    reader = new BufferedReader(device.getReader());
+    // BufferedInputStream avoids an error returned by the USB stack. Double
+    // buffering like this should not be necessary if the USB error turns out to
+    // be an Android bug. This was tested on Honeycomb MR2.
+    reader =
+        new BufferedReader(new InputStreamReader(new BufferedInputStream(device.getInputStream(),
+            STREAM_BUFFER_SIZE), Charset.forName("US-ASCII")));
     writer =
-        new BufferedWriter(new OutputStreamWriter(device.getOutputStream(),
-            Charset.forName("US-ASCII")));
+        new BufferedWriter(new OutputStreamWriter(new BufferedOutputStream(
+            device.getOutputStream(), STREAM_BUFFER_SIZE), Charset.forName("US-ASCII")));
   }
 
   private void write(String command) {