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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package com.google.protobuf;

import static com.google.protobuf.Internal.EMPTY_BYTE_BUFFER;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.Iterator;

class IterableByteBufferInputStream extends InputStream {
  /** The {@link Iterator} with type {@link ByteBuffer} of {@code input} */
  private Iterator iterator;
  /** The current ByteBuffer; */
  private ByteBuffer currentByteBuffer;
  /** The number of ByteBuffers in the input data. */
  private int dataSize;
  /**
   * Current {@code ByteBuffer}'s index
   *
   * 

If index equals dataSize, then all the data in the InputStream has been consumed */ private int currentIndex; /** The current position for current ByteBuffer */ private int currentByteBufferPos; /** Whether current ByteBuffer has an array */ private boolean hasArray; /** * If the current ByteBuffer is unsafe-direct based, currentArray is null; otherwise should be the * array inside ByteBuffer. */ private byte[] currentArray; /** Current ByteBuffer's array offset */ private int currentArrayOffset; /** * If the current ByteBuffer is unsafe-direct based, currentAddress is the start address of this * ByteBuffer; otherwise should be zero. */ private long currentAddress; IterableByteBufferInputStream(Iterable data) { iterator = data.iterator(); dataSize = 0; for (ByteBuffer unused : data) { dataSize++; } currentIndex = -1; if (!getNextByteBuffer()) { currentByteBuffer = EMPTY_BYTE_BUFFER; currentIndex = 0; currentByteBufferPos = 0; currentAddress = 0; } } private boolean getNextByteBuffer() { currentIndex++; if (!iterator.hasNext()) { return false; } currentByteBuffer = iterator.next(); currentByteBufferPos = currentByteBuffer.position(); if (currentByteBuffer.hasArray()) { hasArray = true; currentArray = currentByteBuffer.array(); currentArrayOffset = currentByteBuffer.arrayOffset(); } else { hasArray = false; currentAddress = UnsafeUtil.addressOffset(currentByteBuffer); currentArray = null; } return true; } private void updateCurrentByteBufferPos(int numberOfBytesRead) { currentByteBufferPos += numberOfBytesRead; if (currentByteBufferPos == currentByteBuffer.limit()) { getNextByteBuffer(); } } @Override public int read() throws IOException { if (currentIndex == dataSize) { return -1; } if (hasArray) { int result = currentArray[currentByteBufferPos + currentArrayOffset] & 0xFF; updateCurrentByteBufferPos(1); return result; } else { int result = UnsafeUtil.getByte(currentByteBufferPos + currentAddress) & 0xFF; updateCurrentByteBufferPos(1); return result; } } @Override public int read(byte[] output, int offset, int length) throws IOException { if (currentIndex == dataSize) { return -1; } int remaining = currentByteBuffer.limit() - currentByteBufferPos; if (length > remaining) { length = remaining; } if (hasArray) { System.arraycopy( currentArray, currentByteBufferPos + currentArrayOffset, output, offset, length); updateCurrentByteBufferPos(length); } else { int prevPos = currentByteBuffer.position(); currentByteBuffer.position(currentByteBufferPos); currentByteBuffer.get(output, offset, length); currentByteBuffer.position(prevPos); updateCurrentByteBufferPos(length); } return length; } }





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