Core: Add ByteBufferInputStream and implementations.

Author: rdblue

LICENSE

@@ -228,6 +228,7 @@ This product includes code from Apache Parquet.
 * DynMethods.java
 * DynConstructors.java
 * AssertHelpers.java
+* ByteBufferInputStream implementations and tests
 
 Copyright: 2014-2017 The Apache Software Foundation.
 Home page: https://parquet.apache.org/

core/src/main/java/org/apache/iceberg/io/ByteBufferInputStream.java

@@ -0,0 +1,73 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iceberg.io;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.List;
+
+public abstract class ByteBufferInputStream extends SeekableInputStream {
+
+  public static ByteBufferInputStream wrap(ByteBuffer... buffers) {
+    if (buffers.length == 1) {
+      return new SingleBufferInputStream(buffers[0]);
+    } else {
+      return new MultiBufferInputStream(Arrays.asList(buffers));
+    }
+  }
+
+  public static ByteBufferInputStream wrap(List<ByteBuffer> buffers) {
+    if (buffers.size() == 1) {
+      return new SingleBufferInputStream(buffers.get(0));
+    } else {
+      return new MultiBufferInputStream(buffers);
+    }
+  }
+
+  public long position() throws IOException {
+    return getPos();
+  }
+
+  public void skipFully(long n) throws IOException {
+    long skipped = skip(n);
+    if (skipped < n) {
+      throw new EOFException(
+          "Not enough bytes to skip: " + skipped + " < " + n);
+    }
+  }
+
+  public abstract int read(ByteBuffer out);
+
+  public abstract ByteBuffer slice(int length) throws EOFException;
+
+  public abstract List<ByteBuffer> sliceBuffers(long length) throws EOFException;
+
+  public ByteBufferInputStream sliceStream(long length) throws EOFException {
+    return ByteBufferInputStream.wrap(sliceBuffers(length));
+  }
+
+  public abstract List<ByteBuffer> remainingBuffers();
+
+  public ByteBufferInputStream remainingStream() {
+    return ByteBufferInputStream.wrap(remainingBuffers());
+  }
+}