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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
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();
Java8Compatibility.position(currentByteBuffer, currentByteBufferPos);
currentByteBuffer.get(output, offset, length);
Java8Compatibility.position(currentByteBuffer, prevPos);
updateCurrentByteBufferPos(length);
}
return length;
}
}