implement minimal, read-only versions of RandomAccessFile and ZipFile

classpath/java/io/RandomAccessFile.java

@@ -0,0 +1,62 @@
+package java.io;
+
+public class RandomAccessFile {
+  private long peer;
+  private long length;
+  private long position = 0;
+  
+  public RandomAccessFile(String name, String mode)
+    throws FileNotFoundException
+  {
+    if (! mode.equals("r")) throw new IllegalArgumentException();
+
+    long[] result = new long[2];
+    open(name, result);
+    peer = result[0];
+    length = result[1];
+  }
+
+  private static native void open(String name, long[] result)
+    throws FileNotFoundException;
+
+  public long length() throws IOException {
+    return length;
+  }
+
+  public long getFilePointer() throws IOException {
+    return position;
+  }
+
+  public void seek(long position) throws IOException {
+    if (position < 0 || position > length) throw new IOException();
+
+    this.position = position;
+  }
+
+  public void readFully(byte[] buffer, int offset, int length)
+    throws IOException
+  {
+    if (peer == 0) throw new IOException();
+
+    if (length == 0) return;
+
+    if (position + length > this.length) throw new EOFException();
+
+    if (offset < 0 || offset + length > buffer.length)
+      throw new ArrayIndexOutOfBoundsException();
+
+    copy(peer, position, buffer, offset, length);
+  }
+
+  private static native void copy(long peer, long position, byte[] buffer,
+                                  int offset, int length);
+
+  public void close() throws IOException {
+    if (peer != 0) {
+      close(peer);
+      peer = 0;
+    }
+  }
+
+  private static native void close(long peer);
+}