// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// http://code.google.com/p/protobuf/
//
// 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
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package com.google.protobuf;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
/**
* This class implements a {@link com.google.protobuf.ByteString} backed by a
* single array of bytes, contiguous in memory. It supports substring by
* pointing to only a sub-range of the underlying byte array, meaning that a
* substring will reference the full byte-array of the string it's made from,
* exactly as with {@link String}.
*
* @author carlanton@google.com (Carl Haverl)
*/
class LiteralByteString extends ByteString {
protected final byte[] bytes;
/**
* Creates a {@code LiteralByteString} backed by the given array, without
* copying.
*
* @param bytes array to wrap
*/
LiteralByteString(byte[] bytes) {
this.bytes = bytes;
}
@Override
public byte byteAt(int index) {
// Unlike most methods in this class, this one is a direct implementation
// ignoring the potential offset because we need to do range-checking in the
// substring case anyway.
return bytes[index];
}
@Override
public int size() {
return bytes.length;
}
// =================================================================
// ByteString -> substring
@Override
public ByteString substring(int beginIndex, int endIndex) {
if (beginIndex < 0) {
throw new IndexOutOfBoundsException(
"Beginning index: " + beginIndex + " < 0");
}
if (endIndex > size()) {
throw new IndexOutOfBoundsException("End index: " + endIndex + " > " +
size());
}
int substringLength = endIndex - beginIndex;
if (substringLength < 0) {
throw new IndexOutOfBoundsException(
"Beginning index larger than ending index: " + beginIndex + ", "
+ endIndex);
}
ByteString result;
if (substringLength == 0) {
result = ByteString.EMPTY;
} else {
result = new BoundedByteString(bytes, getOffsetIntoBytes() + beginIndex,
substringLength);
}
return result;
}
// =================================================================
// ByteString -> byte[]
@Override
protected void copyToInternal(byte[] target, int sourceOffset,
int targetOffset, int numberToCopy) {
// Optimized form, not for subclasses, since we don't call
// getOffsetIntoBytes() or check the 'numberToCopy' parameter.
System.arraycopy(bytes, sourceOffset, target, targetOffset, numberToCopy);
}
@Override
public void copyTo(ByteBuffer target) {
target.put(bytes, getOffsetIntoBytes(), size()); // Copies bytes
}
@Override
public ByteBuffer asReadOnlyByteBuffer() {
ByteBuffer byteBuffer =
ByteBuffer.wrap(bytes, getOffsetIntoBytes(), size());
return byteBuffer.asReadOnlyBuffer();
}
@Override
public List<ByteBuffer> asReadOnlyByteBufferList() {
// Return the ByteBuffer generated by asReadOnlyByteBuffer() as a singleton
List<ByteBuffer> result = new ArrayList<ByteBuffer>(1);
result.add(asReadOnlyByteBuffer());
return result;
}
@Override
public void writeTo(OutputStream outputStream) throws IOException {
outputStream.write(toByteArray());
}
@Override
void writeToInternal(OutputStream outputStream, int sourceOffset,
int numberToWrite) throws IOException {
outputStream.write(bytes, getOffsetIntoBytes() + sourceOffset,
numberToWrite);
}
@Override
public String toString(String charsetName)
throws UnsupportedEncodingException {
return new String(bytes, getOffsetIntoBytes(), size(), charsetName);
}
// =================================================================
// UTF-8 decoding
@Override
public boolean isValidUtf8() {
int offset = getOffsetIntoBytes();
return Utf8.isValidUtf8(bytes, offset, offset + size());
}
@Override
protected int partialIsValidUtf8(int state, int offset, int length) {
int index = getOffsetIntoBytes() + offset;
return Utf8.partialIsValidUtf8(state, bytes, index, index + length);
}
// =================================================================
// equals() and hashCode()
@Override
public boolean equals(Object other) {
if (other == this) {
return true;
}
if (!(other instanceof ByteString)) {
return false;
}
if (size() != ((ByteString) other).size()) {
return false;
}
if (size() == 0) {
return true;
}
if (other instanceof LiteralByteString) {
return equalsRange((LiteralByteString) other, 0, size());
} else if (other instanceof RopeByteString) {
return other.equals(this);
} else {
throw new IllegalArgumentException(
"Has a new type of ByteString been created? Found "
+ other.getClass());
}
}
/**
* Check equality of the substring of given length of this object starting at
* zero with another {@code LiteralByteString} substring starting at offset.
*
* @param other what to compare a substring in
* @param offset offset into other
* @param length number of bytes to compare
* @return true for equality of substrings, else false.
*/
boolean equalsRange(LiteralByteString other, int offset, int length) {
if (length > other.size()) {
throw new IllegalArgumentException(
"Length too large: " + length + size());
}
if (offset + length > other.size()) {
throw new IllegalArgumentException(
"Ran off end of other: " + offset + ", " + length + ", " +
other.size());
}
byte[] thisBytes = bytes;
byte[] otherBytes = other.bytes;
int thisLimit = getOffsetIntoBytes() + length;
for (int thisIndex = getOffsetIntoBytes(), otherIndex =
other.getOffsetIntoBytes() + offset;
(thisIndex < thisLimit); ++thisIndex, ++otherIndex) {
if (thisBytes[thisIndex] != otherBytes[otherIndex]) {
return false;
}
}
return true;
}
/**
* Cached hash value. Intentionally accessed via a data race, which
* is safe because of the Java Memory Model's "no out-of-thin-air values"
* guarantees for ints.
*/
private int hash = 0;
/**
* Compute the hashCode using the traditional algorithm from {@link
* ByteString}.
*
* @return hashCode value
*/
@Override
public int hashCode() {
int h = hash;
if (h == 0) {
int size = size();
h = partialHash(size, 0, size);
if (h == 0) {
h = 1;
}
hash = h;
}
return h;
}
@Override
protected int peekCachedHashCode() {
return hash;
}
@Override
protected int partialHash(int h, int offset, int length) {
return hashCode(h, bytes, getOffsetIntoBytes() + offset, length);
}
static int hashCode(int h, byte[] bytes, int offset, int length) {
for (int i = offset; i < offset + length; i++) {
h = h * 31 + bytes[i];
}
return h;
}
static int hashCode(byte[] bytes) {
int h = hashCode(bytes.length, bytes, 0, bytes.length);
return h == 0 ? 1 : h;
}
// =================================================================
// Input stream
@Override
public InputStream newInput() {
return new ByteArrayInputStream(bytes, getOffsetIntoBytes(),
size()); // No copy
}
@Override
public CodedInputStream newCodedInput() {
// We trust CodedInputStream not to modify the bytes, or to give anyone
// else access to them.
return CodedInputStream.newInstance(this);
}
// =================================================================
// ByteIterator
@Override
public ByteIterator iterator() {
return new LiteralByteIterator();
}
private class LiteralByteIterator implements ByteIterator {
private int position;
private final int limit;
private LiteralByteIterator() {
position = 0;
limit = size();
}
public boolean hasNext() {
return (position < limit);
}
public Byte next() {
// Boxing calls Byte.valueOf(byte), which does not instantiate.
return nextByte();
}
public byte nextByte() {
try {
return bytes[position++];
} catch (ArrayIndexOutOfBoundsException e) {
throw new NoSuchElementException(e.getMessage());
}
}
public void remove() {
throw new UnsupportedOperationException();
}
}
// =================================================================
// Internal methods
@Override
protected int getTreeDepth() {
return 0;
}
@Override
protected boolean isBalanced() {
return true;
}
/**
* Offset into {@code bytes[]} to use, non-zero for substrings.
*
* @return always 0 for this class
*/
protected int getOffsetIntoBytes() {
return 0;
}
}