Various bug fixes and optimizations

classpath/java/nio/ByteBuffer.java

@@ -6,17 +6,19 @@ public class ByteBuffer {
   private int capacity;
   private int position;
   private int limit;
+  private final boolean readOnly;
 
   public static ByteBuffer allocate(int capacity) {
-    return new ByteBuffer(new byte[capacity]);
+    return new ByteBuffer(new byte[capacity], false);
   }
 
   public static ByteBuffer wrap(byte[] array) {
-    return new ByteBuffer(array);
+    return new ByteBuffer(array, false);
   }
 
-  private ByteBuffer(byte[] array) {
+  private ByteBuffer(byte[] array, boolean readOnly) {
     this.array = array;
+    this.readOnly = readOnly;
     arrayOffset = 0;
     capacity = array.length;
     limit = capacity;
@@ -34,10 +36,10 @@ public class ByteBuffer {
   }
 
   public ByteBuffer slice() {
-    ByteBuffer buf = new ByteBuffer(array);
+    ByteBuffer buf = new ByteBuffer(array, true);
     buf.arrayOffset = arrayOffset + position;
     buf.position = 0;
-    buf.capacity = capacity - position;
+    buf.capacity = remaining();
     buf.limit = buf.capacity;
     return buf;
   }
@@ -83,13 +85,15 @@ public class ByteBuffer {
   }
 
   public ByteBuffer put(byte val) {
+    checkPut(1);
     array[arrayOffset+(position++)] = val;
     return this;
   }
 
   public ByteBuffer put(ByteBuffer src) {
+    checkPut(src.remaining());
     put(src.array, src.arrayOffset + src.position, src.remaining());
-    position += src.remaining();
+    src.position += src.remaining();
     return this;
   }
 
@@ -98,12 +102,14 @@ public class ByteBuffer {
   }
 
   public ByteBuffer put(byte[] arr, int offset, int len) {
+    checkPut(len);
     System.arraycopy(arr, offset, array, arrayOffset+position, len);
     position += len;
     return this;
   }
 
   public ByteBuffer putInt(int position, int val) {
+    checkPut(position, 4);
     array[arrayOffset+position]   = (byte)((val >> 24) & 0xff);
     array[arrayOffset+position+1] = (byte)((val >> 16) & 0xff);
     array[arrayOffset+position+2] = (byte)((val >>  8) & 0xff);
@@ -112,18 +118,21 @@ public class ByteBuffer {
   }
 
   public ByteBuffer putInt(int val) {
+    checkPut(4);
     putInt(position, val);
     position += 4;
     return this;
   }
 
   public ByteBuffer putShort(short val) {
+    checkPut(2);
     put((byte)((val >> 8) & 0xff));
     put((byte)(val & 0xff));
     return this;
   }
 
   public ByteBuffer putLong(long val) {
+    checkPut(8);
     putInt((int)(val >> 32));
     putInt((int)val);
     return this;
@@ -135,10 +144,12 @@ public class ByteBuffer {
   }
 
   public byte get() {
+    checkGet(1);
     return array[arrayOffset+(position++)];
   }
 
   public byte get(int position) {
+    checkGet(position, 1);
     return array[arrayOffset+position];
   }
 
@@ -149,6 +160,7 @@ public class ByteBuffer {
   }
 
   public int getInt() {
+    checkGet(4);
     int i = get() << 24;
     i |= (get() & 0xff) << 16;
     i |= (get() & 0xff) << 8;
@@ -157,14 +169,36 @@ public class ByteBuffer {
   }
 
   public short getShort() {
+    checkGet(2);
     short s = (short)(get() << 8);
     s |= get() & 0xff;
     return s;
   }
 
   public long getLong() {
+    checkGet(8);
     long l = getInt() << 32;
     l |= getInt() & 0xffffffff;
     return l;
   }
+
+  private void checkPut(int amount) {
+    if (readOnly) throw new ReadOnlyBufferException();
+    if (amount > limit-position) throw new IndexOutOfBoundsException();
+  }
+
+  private void checkPut(int position, int amount) {
+    if (readOnly) throw new ReadOnlyBufferException();
+    if (position < 0 || position+amount > limit)
+      throw new IndexOutOfBoundsException();
+  }
+
+  private void checkGet(int amount) {
+    if (amount > limit-position) throw new IndexOutOfBoundsException();
+  }
+
+  private void checkGet(int position, int amount) {
+    if (position < 0 || position+amount > limit)
+      throw new IndexOutOfBoundsException();
+  }
 }

classpath/java/nio/channels/SocketChannel.java

@@ -57,6 +57,7 @@ public class SocketChannel extends SelectableChannel
     if (! connected) {
       natThrowWriteError(socket);
     }
+    if (b.remaining() == 0) return 0;
     int w = natWrite(socket, b.array(), b.arrayOffset() + b.position(), b.remaining());
     if (w > 0) {
       b.position(b.position() + w);

classpath/java/util/LinkedList.java

@@ -33,6 +33,7 @@ public class LinkedList<T> implements List<T> {
       front = rear = c;
     } else {
       c.next = front;
+      front.prev = c;
       front = c;
     }
   }
@@ -44,6 +45,7 @@ public class LinkedList<T> implements List<T> {
       front = rear = c;
     } else {
       c.prev = rear;
+      rear.next = c;
       rear = c;
     }
   }
@@ -103,7 +105,7 @@ public class LinkedList<T> implements List<T> {
   }
 
   public boolean add(T element) {
-    addFirst(element);
+    addLast(element);
     return true;
   }