content: /*
   * 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.asterix.column.bytes.stream.in;
  
  import java.io.EOFException;
  import java.io.IOException;
  import java.nio.ByteBuffer;
  
  import org.apache.hyracks.data.std.api.IPointable;
  import org.apache.hyracks.storage.am.lsm.btree.column.api.IColumnBufferProvider;
  
  public final class ByteBufferInputStream extends AbstractBytesInputStream {
      private ByteBuffer buffer;
      private int mark = -1;
  
      @Override
      public void reset(IColumnBufferProvider bufferProvider) {
          addBuffer(bufferProvider.getBuffer());
      }
  
      @Override
      protected void addBuffer(ByteBuffer buffer) {
          this.buffer = buffer;
          mark = -1;
      }
  
      @Override
      public void resetAt(int bytesToSkip, AbstractBytesInputStream stream) throws IOException {
          ByteBufferInputStream in = (ByteBufferInputStream) stream;
          buffer = in.buffer.duplicate();
          buffer.position(buffer.position() + bytesToSkip);
          mark = -1;
      }
  
      @Override
      public void read(IPointable pointable, int length) throws EOFException {
          if (buffer.remaining() < length) {
              throw new EOFException();
          }
  
          pointable.set(buffer.array(), buffer.position(), length);
          buffer.position(buffer.position() + length);
      }
  
      @Override
      public int read() throws IOException {
          if (!buffer.hasRemaining()) {
              throw new EOFException();
          }
          return buffer.get() & 0xFF; // as unsigned
      }
  
      @Override
      public int read(byte[] bytes, int offset, int length) throws IOException {
          if (length == 0) {
              return 0;
          }
  
          int remaining = buffer.remaining();
          if (remaining <= 0) {
              return -1;
          }
  
          int bytesToRead = Math.min(remaining, length);
          buffer.get(bytes, offset, bytesToRead);
  
          return bytesToRead;
      }
  
      @Override
      public long skip(long n) {
          if (n == 0) {
              return 0;
          }
  
          if (!buffer.hasRemaining()) {
              return -1;
          }
  
          // buffer.remaining is an int, so this will always fit in an int
          int bytesToSkip = (int) Math.min(buffer.remaining(), n);
          buffer.position(buffer.position() + bytesToSkip);
  
          return bytesToSkip;
      }
  
      @Override
      public int read(ByteBuffer out) {
          int bytesToCopy;
          ByteBuffer copyBuffer;
          if (buffer.remaining() <= out.remaining()) {
              // copy the entire buffer
              bytesToCopy = buffer.remaining();
              copyBuffer = buffer;
          } else {
              // copy a slice of the current buffer
              bytesToCopy = out.remaining();
              copyBuffer = buffer.duplicate();
              copyBuffer.position(buffer.position());
              copyBuffer.limit(buffer.position() + bytesToCopy);
              buffer.position(buffer.position() + bytesToCopy);
          }
  
          out.put(copyBuffer);
          out.flip();
  
          return bytesToCopy;
      }
  
      @Override
      public AbstractBytesInputStream sliceStream(int length) throws EOFException {
          if (buffer.remaining() < length) {
              throw new EOFException();
          }
          ByteBuffer copy = buffer.duplicate();
          copy.position(buffer.position());
          copy.limit(buffer.position() + length);
          ByteBufferInputStream in = new ByteBufferInputStream();
          in.addBuffer(copy);
          buffer.position(buffer.position() + length);
          return in;
      }
  
      @Override
      public AbstractBytesInputStream remainingStream() {
          ByteBuffer remaining = buffer.duplicate();
          remaining.position(buffer.position());
          buffer.position(buffer.limit());
          ByteBufferInputStream in = new ByteBufferInputStream();
          in.addBuffer(remaining);
          return in;
      }
  
      @Override
      public void mark(int readlimit) {
          this.mark = buffer.position();
      }
  
      @Override
      public void reset() throws IOException {
          if (mark >= 0) {
              buffer.position(mark);
              this.mark = -1;
          } else {
              throw new IOException("No mark defined");
          }
      }
  
      @Override
      public int available() {
          return buffer.remaining();
      }
  
      @Override
      public ByteBuffer getBuffer() {
          return buffer;
      }
  }
  