// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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// 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
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//
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package com.google.protobuf;
import static com.google.protobuf.TextFormatEscaper.escapeBytes;
import static java.lang.Integer.toHexString;
import static java.lang.System.identityHashCode;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.UnsupportedCharsetException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.NoSuchElementException;
/**
* Immutable sequence of bytes. Provides conversions to and from {@code byte[]}, {@link
* java.lang.String}, {@link ByteBuffer}, {@link InputStream}, {@link OutputStream}. Also provides a
* conversion to {@link CodedInputStream}.
*
* <p>Like {@link String}, the contents of a {@link ByteString} can never be observed to change, not
* even in the presence of a data race or incorrect API usage in the client code.
*
* <p>Substring is supported by sharing the reference to the immutable underlying bytes.
* Concatenation is likewise supported without copying (long strings) by building a tree of pieces
* in {@link RopeByteString}.
*
* @author crazybob@google.com Bob Lee
* @author kenton@google.com Kenton Varda
* @author carlanton@google.com Carl Haverl
* @author martinrb@google.com Martin Buchholz
*/
public abstract class ByteString implements Iterable<Byte>, Serializable {
/**
* When two strings to be concatenated have a combined length shorter than this, we just copy
* their bytes on {@link #concat(ByteString)}. The trade-off is copy size versus the overhead of
* creating tree nodes in {@link RopeByteString}.
*/
static final int CONCATENATE_BY_COPY_SIZE = 128;
/**
* When copying an InputStream into a ByteString with .readFrom(), the chunks in the underlying
* rope start at 256 bytes, but double each iteration up to 8192 bytes.
*/
static final int MIN_READ_FROM_CHUNK_SIZE = 0x100; // 256b
static final int MAX_READ_FROM_CHUNK_SIZE = 0x2000; // 8k
/** Empty {@code ByteString}. */
public static final ByteString EMPTY = new LiteralByteString(Internal.EMPTY_BYTE_ARRAY);
/**
* An interface to efficiently copy {@code byte[]}.
*
* <p>One of the noticeable costs of copying a byte[] into a new array using {@code
* System.arraycopy} is nullification of a new buffer before the copy. It has been shown the
* Hotspot VM is capable to intrisicfy {@code Arrays.copyOfRange} operation to avoid this
* expensive nullification and provide substantial performance gain. Unfortunately this does not
* hold on Android runtimes and could make the copy slightly slower due to additional code in the
* {@code Arrays.copyOfRange}. Thus we provide two different implementation for array copier for
* Hotspot and Android runtimes.
*/
private interface ByteArrayCopier {
/** Copies the specified range of the specified array into a new array */
byte[] copyFrom(byte[] bytes, int offset, int size);
}
/** Implementation of {@code ByteArrayCopier} which uses {@link System#arraycopy}. */
private static final class SystemByteArrayCopier implements ByteArrayCopier {
@Override
public byte[] copyFrom(byte[] bytes, int offset, int size) {
byte[] copy = new byte[size];
System.arraycopy(bytes, offset, copy, 0, size);
return copy;
}
}
/** Implementation of {@code ByteArrayCopier} which uses {@link Arrays#copyOfRange}. */
private static final class ArraysByteArrayCopier implements ByteArrayCopier {
@Override
public byte[] copyFrom(byte[] bytes, int offset, int size) {
return Arrays.copyOfRange(bytes, offset, offset + size);
}
}
private static final ByteArrayCopier byteArrayCopier;
static {
byteArrayCopier =
Android.isOnAndroidDevice() ? new SystemByteArrayCopier() : new ArraysByteArrayCopier();
}
/**
* 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. A value of 0 implies that the
* hash has not been set.
*/
private int hash = 0;
// This constructor is here to prevent subclassing outside of this package,
ByteString() {}
/**
* Gets the byte at the given index. This method should be used only for random access to
* individual bytes. To access bytes sequentially, use the {@link ByteIterator} returned by {@link
* #iterator()}, and call {@link #substring(int, int)} first if necessary.
*
* @param index index of byte
* @return the value
* @throws IndexOutOfBoundsException {@code index < 0 or index >= size}
*/
public abstract byte byteAt(int index);
/**
* Gets the byte at the given index, assumes bounds checking has already been performed.
*
* @param index index of byte
* @return the value
* @throws IndexOutOfBoundsException {@code index < 0 or index >= size}
*/
abstract byte internalByteAt(int index);
/**
* Return a {@link ByteString.ByteIterator} over the bytes in the ByteString. To avoid
* auto-boxing, you may get the iterator manually and call {@link ByteIterator#nextByte()}.
*
* @return the iterator
*/
@Override
public ByteIterator iterator() {
return new AbstractByteIterator() {
private int position = 0;
private final int limit = size();
@Override
public boolean hasNext() {
return position < limit;
}
@Override
public byte nextByte() {
int currentPos = position;
if (currentPos >= limit) {
throw new NoSuchElementException();
}
position = currentPos + 1;
return internalByteAt(currentPos);
}
};
}
/**
* This interface extends {@code Iterator<Byte>}, so that we can return an unboxed {@code byte}.
*/
public interface ByteIterator extends Iterator<Byte> {
/**
* An alternative to {@link Iterator#next()} that returns an unboxed primitive {@code byte}.
*
* @return the next {@code byte} in the iteration
* @throws NoSuchElementException if the iteration has no more elements
*/
byte nextByte();
}
abstract static class AbstractByteIterator implements ByteIterator {
@Override
public final Byte next() {
// Boxing calls Byte.valueOf(byte), which does not instantiate.
return nextByte();
}
@Override
public final void remove() {
throw new UnsupportedOperationException();
}
}
/**
* Gets the number of bytes.
*
* @return size in bytes
*/
public abstract int size();
/**
* Returns {@code true} if the size is {@code 0}, {@code false} otherwise.
*
* @return true if this is zero bytes long
*/
public final boolean isEmpty() {
return size() == 0;
}
// =================================================================
// Comparison
private static final int UNSIGNED_BYTE_MASK = 0xFF;
/**
* Returns the value of the given byte as an integer, interpreting the byte as an unsigned value.
* That is, returns {@code value + 256} if {@code value} is negative; {@code value} itself
* otherwise.
*
* <p>Note: This code was copied from {@link com.google.common.primitives.UnsignedBytes#toInt}, as
* Guava libraries cannot be used in the {@code com.google.protobuf} package.
*/
private static int toInt(byte value) {
return value & UNSIGNED_BYTE_MASK;
}
/**
* Compares two {@link ByteString}s lexicographically, treating their contents as unsigned byte
* values between 0 and 255 (inclusive).
*
* <p>For example, {@code (byte) -1} is considered to be greater than {@code (byte) 1} because it
* is interpreted as an unsigned value, {@code 255}.
*/
private static final Comparator<ByteString> UNSIGNED_LEXICOGRAPHICAL_COMPARATOR =
new Comparator<ByteString>() {
@Override
public int compare(ByteString former, ByteString latter) {
ByteIterator formerBytes = former.iterator();
ByteIterator latterBytes = latter.iterator();
while (formerBytes.hasNext() && latterBytes.hasNext()) {
// Note: This code was copied from com.google.common.primitives.UnsignedBytes#compare,
// as Guava libraries cannot be used in the {@code com.google.protobuf} package.
int result =
Integer.compare(toInt(formerBytes.nextByte()), toInt(latterBytes.nextByte()));
if (result != 0) {
return result;
}
}
return Integer.compare(former.size(), latter.size());
}
};
/**
* Returns a {@link Comparator} which compares {@link ByteString}-s lexicographically
* as sequences of unsigned bytes (i.e. values between 0 and 255, inclusive).
*
* <p>For example, {@code (byte) -1} is considered to be greater than {@code (byte) 1} because it
* is interpreted as an unsigned value, {@code 255}:
*
* <ul>
* <li>{@code `-1` -> 0b11111111 (two's complement) -> 255}
* <li>{@code `1` -> 0b00000001 -> 1}
* </ul>
*/
public static Comparator<ByteString> unsignedLexicographicalComparator() {
return UNSIGNED_LEXICOGRAPHICAL_COMPARATOR;
}
// =================================================================
// ByteString -> substring
/**
* Return the substring from {@code beginIndex}, inclusive, to the end of the string.
*
* @param beginIndex start at this index
* @return substring sharing underlying data
* @throws IndexOutOfBoundsException if {@code beginIndex < 0} or {@code beginIndex > size()}.
*/
public final ByteString substring(int beginIndex) {
return substring(beginIndex, size());
}
/**
* Return the substring from {@code beginIndex}, inclusive, to {@code endIndex}, exclusive.
*
* @param beginIndex start at this index
* @param endIndex the last character is the one before this index
* @return substring sharing underlying data
* @throws IndexOutOfBoundsException if {@code beginIndex < 0}, {@code endIndex > size()}, or
* {@code beginIndex > endIndex}.
*/
public abstract ByteString substring(int beginIndex, int endIndex);
/**
* Tests if this bytestring starts with the specified prefix. Similar to {@link
* String#startsWith(String)}
*
* @param prefix the prefix.
* @return <code>true</code> if the byte sequence represented by the argument is a prefix of the
* byte sequence represented by this string; <code>false</code> otherwise.
*/
public final boolean startsWith(ByteString prefix) {
return size() >= prefix.size() && substring(0, prefix.size()).equals(prefix);
}
/**
* Tests if this bytestring ends with the specified suffix. Similar to {@link
* String#endsWith(String)}
*
* @param suffix the suffix.
* @return <code>true</code> if the byte sequence represented by the argument is a suffix of the
* byte sequence represented by this string; <code>false</code> otherwise.
*/
public final boolean endsWith(ByteString suffix) {
return size() >= suffix.size() && substring(size() - suffix.size()).equals(suffix);
}
// =================================================================
// byte[] -> ByteString
/**
* Copies the given bytes into a {@code ByteString}.
*
* @param bytes source array
* @param offset offset in source array
* @param size number of bytes to copy
* @return new {@code ByteString}
* @throws IndexOutOfBoundsException if {@code offset} or {@code size} are out of bounds
*/
public static ByteString copyFrom(byte[] bytes, int offset, int size) {
checkRange(offset, offset + size, bytes.length);
return new LiteralByteString(byteArrayCopier.copyFrom(bytes, offset, size));
}
/**
* Copies the given bytes into a {@code ByteString}.
*
* @param bytes to copy
* @return new {@code ByteString}
*/
public static ByteString copyFrom(byte[] bytes) {
return copyFrom(bytes, 0, bytes.length);
}
/** Wraps the given bytes into a {@code ByteString}. Intended for internal only usage. */
static ByteString wrap(ByteBuffer buffer) {
if (buffer.hasArray()) {
final int offset = buffer.arrayOffset();
return ByteString.wrap(buffer.array(), offset + buffer.position(), buffer.remaining());
} else {
return new NioByteString(buffer);
}
}
/**
* Wraps the given bytes into a {@code ByteString}. Intended for internal only usage to force a
* classload of ByteString before LiteralByteString.
*/
static ByteString wrap(byte[] bytes) {
// TODO(dweis): Return EMPTY when bytes are empty to reduce allocations?
return new LiteralByteString(bytes);
}
/**
* Wraps the given bytes into a {@code ByteString}. Intended for internal only usage to force a
* classload of ByteString before BoundedByteString and LiteralByteString.
*/
static ByteString wrap(byte[] bytes, int offset, int length) {
return new BoundedByteString(bytes, offset, length);
}
/**
* Copies the next {@code size} bytes from a {@code java.nio.ByteBuffer} into a {@code
* ByteString}.
*
* @param bytes source buffer
* @param size number of bytes to copy
* @return new {@code ByteString}
* @throws IndexOutOfBoundsException if {@code size > bytes.remaining()}
*/
public static ByteString copyFrom(ByteBuffer bytes, int size) {
checkRange(0, size, bytes.remaining());
byte[] copy = new byte[size];
bytes.get(copy);
return new LiteralByteString(copy);
}
/**
* Copies the remaining bytes from a {@code java.nio.ByteBuffer} into a {@code ByteString}.
*
* @param bytes sourceBuffer
* @return new {@code ByteString}
*/
public static ByteString copyFrom(ByteBuffer bytes) {
return copyFrom(bytes, bytes.remaining());
}
/**
* Encodes {@code text} into a sequence of bytes using the named charset and returns the result as
* a {@code ByteString}.
*
* @param text source string
* @param charsetName encoding to use
* @return new {@code ByteString}
* @throws UnsupportedEncodingException if the encoding isn't found
*/
public static ByteString copyFrom(String text, String charsetName)
throws UnsupportedEncodingException {
return new LiteralByteString(text.getBytes(charsetName));
}
/**
* Encodes {@code text} into a sequence of bytes using the named charset and returns the result as
* a {@code ByteString}.
*
* @param text source string
* @param charset encode using this charset
* @return new {@code ByteString}
*/
public static ByteString copyFrom(String text, Charset charset) {
return new LiteralByteString(text.getBytes(charset));
}
/**
* Encodes {@code text} into a sequence of UTF-8 bytes and returns the result as a {@code
* ByteString}.
*
* @param text source string
* @return new {@code ByteString}
*/
public static ByteString copyFromUtf8(String text) {
return new LiteralByteString(text.getBytes(Internal.UTF_8));
}
// =================================================================
// InputStream -> ByteString
/**
* Completely reads the given stream's bytes into a {@code ByteString}, blocking if necessary
* until all bytes are read through to the end of the stream.
*
* <p><b>Performance notes:</b> The returned {@code ByteString} is an immutable tree of byte
* arrays ("chunks") of the stream data. The first chunk is small, with subsequent chunks each
* being double the size, up to 8K.
*
* <p>Each byte read from the input stream will be copied twice to ensure that the resulting
* ByteString is truly immutable.
*
* @param streamToDrain The source stream, which is read completely but not closed.
* @return A new {@code ByteString} which is made up of chunks of various sizes, depending on the
* behavior of the underlying stream.
* @throws IOException IOException is thrown if there is a problem reading the underlying stream.
*/
public static ByteString readFrom(InputStream streamToDrain) throws IOException {
return readFrom(streamToDrain, MIN_READ_FROM_CHUNK_SIZE, MAX_READ_FROM_CHUNK_SIZE);
}
/**
* Completely reads the given stream's bytes into a {@code ByteString}, blocking if necessary
* until all bytes are read through to the end of the stream.
*
* <p><b>Performance notes:</b> The returned {@code ByteString} is an immutable tree of byte
* arrays ("chunks") of the stream data. The chunkSize parameter sets the size of these byte
* arrays.
*
* <p>Each byte read from the input stream will be copied twice to ensure that the resulting
* ByteString is truly immutable.
*
* @param streamToDrain The source stream, which is read completely but not closed.
* @param chunkSize The size of the chunks in which to read the stream.
* @return A new {@code ByteString} which is made up of chunks of the given size.
* @throws IOException IOException is thrown if there is a problem reading the underlying stream.
*/
public static ByteString readFrom(InputStream streamToDrain, int chunkSize) throws IOException {
return readFrom(streamToDrain, chunkSize, chunkSize);
}
// Helper method that takes the chunk size range as a parameter.
public static ByteString readFrom(InputStream streamToDrain, int minChunkSize, int maxChunkSize)
throws IOException {
Collection<ByteString> results = new ArrayList<ByteString>();
// copy the inbound bytes into a list of chunks; the chunk size
// grows exponentially to support both short and long streams.
int chunkSize = minChunkSize;
while (true) {
ByteString chunk = readChunk(streamToDrain, chunkSize);
if (chunk == null) {
break;
}
results.add(chunk);
chunkSize = Math.min(chunkSize * 2, maxChunkSize);
}
return ByteString.copyFrom(results);
}
/**
* Blocks until a chunk of the given size can be made from the stream, or EOF is reached. Calls
* read() repeatedly in case the given stream implementation doesn't completely fill the given
* buffer in one read() call.
*
* @return A chunk of the desired size, or else a chunk as large as was available when end of
* stream was reached. Returns null if the given stream had no more data in it.
*/
private static ByteString readChunk(InputStream in, final int chunkSize) throws IOException {
final byte[] buf = new byte[chunkSize];
int bytesRead = 0;
while (bytesRead < chunkSize) {
final int count = in.read(buf, bytesRead, chunkSize - bytesRead);
if (count == -1) {
break;
}
bytesRead += count;
}
if (bytesRead == 0) {
return null;
}
// Always make a copy since InputStream could steal a reference to buf.
return ByteString.copyFrom(buf, 0, bytesRead);
}
// =================================================================
// Multiple ByteStrings -> One ByteString
/**
* Concatenate the given {@code ByteString} to this one. Short concatenations, of total size
* smaller than {@link ByteString#CONCATENATE_BY_COPY_SIZE}, are produced by copying the
* underlying bytes (as per Rope.java, <a
* href="http://www.cs.ubc.ca/local/reading/proceedings/spe91-95/spe/vol25/issue12/spe986.pdf">
* BAP95 </a>. In general, the concatenate involves no copying.
*
* @param other string to concatenate
* @return a new {@code ByteString} instance
*/
public final ByteString concat(ByteString other) {
if (Integer.MAX_VALUE - size() < other.size()) {
throw new IllegalArgumentException(
"ByteString would be too long: " + size() + "+" + other.size());
}
return RopeByteString.concatenate(this, other);
}
/**
* Concatenates all byte strings in the iterable and returns the result. This is designed to run
* in O(list size), not O(total bytes).
*
* <p>The returned {@code ByteString} is not necessarily a unique object. If the list is empty,
* the returned object is the singleton empty {@code ByteString}. If the list has only one
* element, that {@code ByteString} will be returned without copying.
*
* @param byteStrings strings to be concatenated
* @return new {@code ByteString}
*/
public static ByteString copyFrom(Iterable<ByteString> byteStrings) {
// Determine the size;
final int size;
if (!(byteStrings instanceof Collection)) {
int tempSize = 0;
for (Iterator<ByteString> iter = byteStrings.iterator();
iter.hasNext();
iter.next(), ++tempSize) {}
size = tempSize;
} else {
size = ((Collection<ByteString>) byteStrings).size();
}
if (size == 0) {
return EMPTY;
}
return balancedConcat(byteStrings.iterator(), size);
}
// Internal function used by copyFrom(Iterable<ByteString>).
// Create a balanced concatenation of the next "length" elements from the
// iterable.
private static ByteString balancedConcat(Iterator<ByteString> iterator, int length) {
if (length < 1) {
throw new IllegalArgumentException(String.format("length (%s) must be >= 1", length));
}
ByteString result;
if (length == 1) {
result = iterator.next();
} else {
int halfLength = length >>> 1;
ByteString left = balancedConcat(iterator, halfLength);
ByteString right = balancedConcat(iterator, length - halfLength);
result = left.concat(right);
}
return result;
}
// =================================================================
// ByteString -> byte[]
/**
* Copies bytes into a buffer at the given offset.
*
* <p>To copy a subset of bytes, you call this method on the return value of {@link
* #substring(int, int)}. Example: {@code byteString.substring(start, end).copyTo(target, offset)}
*
* @param target buffer to copy into
* @param offset in the target buffer
* @throws IndexOutOfBoundsException if the offset is negative or too large
*/
public void copyTo(byte[] target, int offset) {
copyTo(target, 0, offset, size());
}
/**
* Copies bytes into a buffer.
*
* @param target buffer to copy into
* @param sourceOffset offset within these bytes
* @param targetOffset offset within the target buffer
* @param numberToCopy number of bytes to copy
* @throws IndexOutOfBoundsException if an offset or size is negative or too large
* @deprecated Instead, call {@code byteString.substring(sourceOffset, sourceOffset +
* numberToCopy).copyTo(target, targetOffset)}
*/
@Deprecated
public final void copyTo(byte[] target, int sourceOffset, int targetOffset, int numberToCopy) {
checkRange(sourceOffset, sourceOffset + numberToCopy, size());
checkRange(targetOffset, targetOffset + numberToCopy, target.length);
if (numberToCopy > 0) {
copyToInternal(target, sourceOffset, targetOffset, numberToCopy);
}
}
/**
* Internal (package private) implementation of {@link #copyTo(byte[],int,int,int)}. It assumes
* that all error checking has already been performed and that {@code numberToCopy > 0}.
*/
protected abstract void copyToInternal(
byte[] target, int sourceOffset, int targetOffset, int numberToCopy);
/**
* Copies bytes into a ByteBuffer.
*
* <p>To copy a subset of bytes, you call this method on the return value of {@link
* #substring(int, int)}. Example: {@code byteString.substring(start, end).copyTo(target)}
*
* @param target ByteBuffer to copy into.
* @throws java.nio.ReadOnlyBufferException if the {@code target} is read-only
* @throws java.nio.BufferOverflowException if the {@code target}'s remaining() space is not large
* enough to hold the data.
*/
public abstract void copyTo(ByteBuffer target);
/**
* Copies bytes to a {@code byte[]}.
*
* @return copied bytes
*/
public final byte[] toByteArray() {
final int size = size();
if (size == 0) {
return Internal.EMPTY_BYTE_ARRAY;
}
byte[] result = new byte[size];
copyToInternal(result, 0, 0, size);
return result;
}
/**
* Writes a copy of the contents of this byte string to the specified output stream argument.
*
* @param out the output stream to which to write the data.
* @throws IOException if an I/O error occurs.
*/
public abstract void writeTo(OutputStream out) throws IOException;
/**
* Writes a specified part of this byte string to an output stream.
*
* @param out the output stream to which to write the data.
* @param sourceOffset offset within these bytes
* @param numberToWrite number of bytes to write
* @throws IOException if an I/O error occurs.
* @throws IndexOutOfBoundsException if an offset or size is negative or too large
*/
final void writeTo(OutputStream out, int sourceOffset, int numberToWrite) throws IOException {
checkRange(sourceOffset, sourceOffset + numberToWrite, size());
if (numberToWrite > 0) {
writeToInternal(out, sourceOffset, numberToWrite);
}
}
/**
* Internal version of {@link #writeTo(OutputStream,int,int)} that assumes all error checking has
* already been done.
*/
abstract void writeToInternal(OutputStream out, int sourceOffset, int numberToWrite)
throws IOException;
/**
* Writes this {@link ByteString} to the provided {@link ByteOutput}. Calling this method may
* result in multiple operations on the target {@link ByteOutput}.
*
* <p>This method may expose internal backing buffers of the {@link ByteString} to the {@link
* ByteOutput} in order to avoid additional copying overhead. It would be possible for a malicious
* {@link ByteOutput} to corrupt the {@link ByteString}. Use with caution!
*
* @param byteOutput the output target to receive the bytes
* @throws IOException if an I/O error occurs
* @see UnsafeByteOperations#unsafeWriteTo(ByteString, ByteOutput)
*/
abstract void writeTo(ByteOutput byteOutput) throws IOException;
/**
* This method behaves exactly the same as {@link #writeTo(ByteOutput)} unless the {@link
* ByteString} is a rope. For ropes, the leaf nodes are written in reverse order to the {@code
* byteOutput}.
*
* @param byteOutput the output target to receive the bytes
* @throws IOException if an I/O error occurs
* @see UnsafeByteOperations#unsafeWriteToReverse(ByteString, ByteOutput)
*/
abstract void writeToReverse(ByteOutput byteOutput) throws IOException;
/**
* Constructs a read-only {@code java.nio.ByteBuffer} whose content is equal to the contents of
* this byte string. The result uses the same backing array as the byte string, if possible.
*
* @return wrapped bytes
*/
public abstract ByteBuffer asReadOnlyByteBuffer();
/**
* Constructs a list of read-only {@code java.nio.ByteBuffer} objects such that the concatenation
* of their contents is equal to the contents of this byte string. The result uses the same
* backing arrays as the byte string.
*
* <p>By returning a list, implementations of this method may be able to avoid copying even when
* there are multiple backing arrays.
*
* @return a list of wrapped bytes
*/
public abstract List<ByteBuffer> asReadOnlyByteBufferList();
/**
* Constructs a new {@code String} by decoding the bytes using the specified charset.
*
* @param charsetName encode using this charset
* @return new string
* @throws UnsupportedEncodingException if charset isn't recognized
*/
public final String toString(String charsetName) throws UnsupportedEncodingException {
try {
return toString(Charset.forName(charsetName));
} catch (UnsupportedCharsetException e) {
UnsupportedEncodingException exception = new UnsupportedEncodingException(charsetName);
exception.initCause(e);
throw exception;
}
}
/**
* Constructs a new {@code String} by decoding the bytes using the specified charset. Returns the
* same empty String if empty.
*
* @param charset encode using this charset
* @return new string
*/
public final String toString(Charset charset) {
return size() == 0 ? "" : toStringInternal(charset);
}
/**
* Constructs a new {@code String} by decoding the bytes using the specified charset.
*
* @param charset encode using this charset
* @return new string
*/
protected abstract String toStringInternal(Charset charset);
// =================================================================
// UTF-8 decoding
/**
* Constructs a new {@code String} by decoding the bytes as UTF-8.
*
* @return new string using UTF-8 encoding
*/
public final String toStringUtf8() {
return toString(Internal.UTF_8);
}
/**
* Tells whether this {@code ByteString} represents a well-formed UTF-8 byte sequence, such that
* the original bytes can be converted to a String object and then round tripped back to bytes
* without loss.
*
* <p>More precisely, returns {@code true} whenever:
*
* <pre>{@code
* Arrays.equals(byteString.toByteArray(),
* new String(byteString.toByteArray(), "UTF-8").getBytes("UTF-8"))
* }</pre>
*
* <p>This method returns {@code false} for "overlong" byte sequences, as well as for 3-byte
* sequences that would map to a surrogate character, in accordance with the restricted definition
* of UTF-8 introduced in Unicode 3.1. Note that the UTF-8 decoder included in Oracle's JDK has
* been modified to also reject "overlong" byte sequences, but (as of 2011) still accepts 3-byte
* surrogate character byte sequences.
*
* <p>See the Unicode Standard,<br>
* Table 3-6. <em>UTF-8 Bit Distribution</em>,<br>
* Table 3-7. <em>Well Formed UTF-8 Byte Sequences</em>.
*
* @return whether the bytes in this {@code ByteString} are a well-formed UTF-8 byte sequence
*/
public abstract boolean isValidUtf8();
/**
* Tells whether the given byte sequence is a well-formed, malformed, or incomplete UTF-8 byte
* sequence. This method accepts and returns a partial state result, allowing the bytes for a
* complete UTF-8 byte sequence to be composed from multiple {@code ByteString} segments.
*
* @param state either {@code 0} (if this is the initial decoding operation) or the value returned
* from a call to a partial decoding method for the previous bytes
* @param offset offset of the first byte to check
* @param length number of bytes to check
* @return {@code -1} if the partial byte sequence is definitely malformed, {@code 0} if it is
* well-formed (no additional input needed), or, if the byte sequence is "incomplete", i.e.
* apparently terminated in the middle of a character, an opaque integer "state" value
* containing enough information to decode the character when passed to a subsequent
* invocation of a partial decoding method.
*/
protected abstract int partialIsValidUtf8(int state, int offset, int length);
// =================================================================
// equals() and hashCode()
@Override
public abstract boolean equals(Object o);
/** Base class for leaf {@link ByteString}s (i.e. non-ropes). */
abstract static class LeafByteString extends ByteString {
@Override
protected final int getTreeDepth() {
return 0;
}
@Override
protected final boolean isBalanced() {
return true;
}
@Override
void writeToReverse(ByteOutput byteOutput) throws IOException {
writeTo(byteOutput);
}
/**
* Check equality of the substring of given length of this object starting at zero with another
* {@code ByteString} 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.
*/
abstract boolean equalsRange(ByteString other, int offset, int length);
}
/**
* Compute the hashCode using the traditional algorithm from {@link ByteString}.
*
* @return hashCode value
*/
@Override
public final 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;
}
// =================================================================
// Input stream
/**
* Creates an {@code InputStream} which can be used to read the bytes.
*
* <p>The {@link InputStream} returned by this method is guaranteed to be completely non-blocking.
* The method {@link InputStream#available()} returns the number of bytes remaining in the stream.
* The methods {@link InputStream#read(byte[])}, {@link InputStream#read(byte[],int,int)} and
* {@link InputStream#skip(long)} will read/skip as many bytes as are available. The method {@link
* InputStream#markSupported()} returns {@code true}.
*
* <p>The methods in the returned {@link InputStream} might <b>not</b> be thread safe.
*
* @return an input stream that returns the bytes of this byte string.
*/
public abstract InputStream newInput();
/**
* Creates a {@link CodedInputStream} which can be used to read the bytes. Using this is often
* more efficient than creating a {@link CodedInputStream} that wraps the result of {@link
* #newInput()}.
*
* @return stream based on wrapped data
*/
public abstract CodedInputStream newCodedInput();
// =================================================================
// Output stream
/**
* Creates a new {@link Output} with the given initial capacity. Call {@link
* Output#toByteString()} to create the {@code ByteString} instance.
*
* <p>A {@link ByteString.Output} offers the same functionality as a {@link
* ByteArrayOutputStream}, except that it returns a {@link ByteString} rather than a {@code byte}
* array.
*
* @param initialCapacity estimate of number of bytes to be written
* @return {@code OutputStream} for building a {@code ByteString}
*/
public static Output newOutput(int initialCapacity) {
return new Output(initialCapacity);
}
/**
* Creates a new {@link Output}. Call {@link Output#toByteString()} to create the {@code
* ByteString} instance.
*
* <p>A {@link ByteString.Output} offers the same functionality as a {@link
* ByteArrayOutputStream}, except that it returns a {@link ByteString} rather than a {@code byte
* array}.
*
* @return {@code OutputStream} for building a {@code ByteString}
*/
public static Output newOutput() {
return new Output(CONCATENATE_BY_COPY_SIZE);
}
/**
* Outputs to a {@code ByteString} instance. Call {@link #toByteString()} to create the {@code
* ByteString} instance.
*/
public static final class Output extends OutputStream {
// Implementation note.
// The public methods of this class must be synchronized. ByteStrings
// are guaranteed to be immutable. Without some sort of locking, it could
// be possible for one thread to call toByteSring(), while another thread
// is still modifying the underlying byte array.
private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
// argument passed by user, indicating initial capacity.
private final int initialCapacity;
// ByteStrings to be concatenated to create the result
private final ArrayList<ByteString> flushedBuffers;
// Total number of bytes in the ByteStrings of flushedBuffers
private int flushedBuffersTotalBytes;
// Current buffer to which we are writing
private byte[] buffer;
// Location in buffer[] to which we write the next byte.
private int bufferPos;
/**
* Creates a new ByteString output stream with the specified initial capacity.
*
* @param initialCapacity the initial capacity of the output stream.
*/
Output(int initialCapacity) {
if (initialCapacity < 0) {
throw new IllegalArgumentException("Buffer size < 0");
}
this.initialCapacity = initialCapacity;
this.flushedBuffers = new ArrayList<ByteString>();
this.buffer = new byte[initialCapacity];
}
@Override
public synchronized void write(int b) {
if (bufferPos == buffer.length) {
flushFullBuffer(1);
}
buffer[bufferPos++] = (byte) b;
}
@Override
public synchronized void write(byte[] b, int offset, int length) {
if (length <= buffer.length - bufferPos) {
// The bytes can fit into the current buffer.
System.arraycopy(b, offset, buffer, bufferPos, length);
bufferPos += length;
} else {
// Use up the current buffer
int copySize = buffer.length - bufferPos;
System.arraycopy(b, offset, buffer, bufferPos, copySize);
offset += copySize;
length -= copySize;
// Flush the buffer, and get a new buffer at least big enough to cover
// what we still need to output
flushFullBuffer(length);
System.arraycopy(b, offset, buffer, /* count= */ 0, length);
bufferPos = length;
}
}
/**
* Creates a byte string. Its size is the current size of this output stream and its output has
* been copied to it.
*
* @return the current contents of this output stream, as a byte string.
*/
public synchronized ByteString toByteString() {
flushLastBuffer();
return ByteString.copyFrom(flushedBuffers);
}
/** Implement java.util.Arrays.copyOf() for jdk 1.5. */
private byte[] copyArray(byte[] buffer, int length) {
byte[] result = new byte[length];
System.arraycopy(buffer, 0, result, 0, Math.min(buffer.length, length));
return result;
}
/**
* Writes the complete contents of this byte array output stream to the specified output stream
* argument.
*
* @param out the output stream to which to write the data.
* @throws IOException if an I/O error occurs.
*/
public void writeTo(OutputStream out) throws IOException {
ByteString[] cachedFlushBuffers;
byte[] cachedBuffer;
int cachedBufferPos;
synchronized (this) {
// Copy the information we need into local variables so as to hold
// the lock for as short a time as possible.
cachedFlushBuffers = flushedBuffers.toArray(new ByteString[flushedBuffers.size()]);
cachedBuffer = buffer;
cachedBufferPos = bufferPos;
}
for (ByteString byteString : cachedFlushBuffers) {
byteString.writeTo(out);
}
out.write(copyArray(cachedBuffer, cachedBufferPos));
}
/**
* Returns the current size of the output stream.
*
* @return the current size of the output stream
*/
public synchronized int size() {
return flushedBuffersTotalBytes + bufferPos;
}
/**
* Resets this stream, so that all currently accumulated output in the output stream is
* discarded. The output stream can be used again, reusing the already allocated buffer space.
*/
public synchronized void reset() {
flushedBuffers.clear();
flushedBuffersTotalBytes = 0;
bufferPos = 0;
}
@Override
public String toString() {
return String.format(
"<ByteString.Output@%s size=%d>",
Integer.toHexString(System.identityHashCode(this)), size());
}
/**
* Internal function used by writers. The current buffer is full, and the writer needs a new
* buffer whose size is at least the specified minimum size.
*/
private void flushFullBuffer(int minSize) {
flushedBuffers.add(new LiteralByteString(buffer));
flushedBuffersTotalBytes += buffer.length;
// We want to increase our total capacity by 50%, but as a minimum,
// the new buffer should also at least be >= minSize and
// >= initial Capacity.
int newSize = Math.max(initialCapacity, Math.max(minSize, flushedBuffersTotalBytes >>> 1));
buffer = new byte[newSize];
bufferPos = 0;
}
/**
* Internal function used by {@link #toByteString()}. The current buffer may or may not be full,
* but it needs to be flushed.
*/
private void flushLastBuffer() {
if (bufferPos < buffer.length) {
if (bufferPos > 0) {
byte[] bufferCopy = copyArray(buffer, bufferPos);
flushedBuffers.add(new LiteralByteString(bufferCopy));
}
// We reuse this buffer for further writes.
} else {
// Buffer is completely full. Huzzah.
flushedBuffers.add(new LiteralByteString(buffer));
// 99% of the time, we're not going to use this OutputStream again.
// We set buffer to an empty byte stream so that we're handling this
// case without wasting space. In the rare case that more writes
// *do* occur, this empty buffer will be flushed and an appropriately
// sized new buffer will be created.
buffer = EMPTY_BYTE_ARRAY;
}
flushedBuffersTotalBytes += bufferPos;
bufferPos = 0;
}
}
/**
* Constructs a new {@code ByteString} builder, which allows you to efficiently construct a {@code
* ByteString} by writing to a {@link CodedOutputStream}. Using this is much more efficient than
* calling {@code newOutput()} and wrapping that in a {@code CodedOutputStream}.
*
* <p>This is package-private because it's a somewhat confusing interface. Users can call {@link
* Message#toByteString()} instead of calling this directly.
*
* @param size The target byte size of the {@code ByteString}. You must write exactly this many
* bytes before building the result.
* @return the builder
*/
static CodedBuilder newCodedBuilder(int size) {
return new CodedBuilder(size);
}
/** See {@link ByteString#newCodedBuilder(int)}. */
static final class CodedBuilder {
private final CodedOutputStream output;
private final byte[] buffer;
private CodedBuilder(int size) {
buffer = new byte[size];
output = CodedOutputStream.newInstance(buffer);
}
public ByteString build() {
output.checkNoSpaceLeft();
// We can be confident that the CodedOutputStream will not modify the
// underlying bytes anymore because it already wrote all of them. So,
// no need to make a copy.
return new LiteralByteString(buffer);
}
public CodedOutputStream getCodedOutput() {
return output;
}
}
// =================================================================
// Methods {@link RopeByteString} needs on instances, which aren't part of the
// public API.
/**
* Return the depth of the tree representing this {@code ByteString}, if any, whose root is this
* node. If this is a leaf node, return 0.
*
* @return tree depth or zero
*/
protected abstract int getTreeDepth();
/**
* Return {@code true} if this ByteString is literal (a leaf node) or a flat-enough tree in the
* sense of {@link RopeByteString}.
*
* @return true if the tree is flat enough
*/
protected abstract boolean isBalanced();
/**
* Return the cached hash code if available.
*
* @return value of cached hash code or 0 if not computed yet
*/
protected final int peekCachedHashCode() {
return hash;
}
/**
* Compute the hash across the value bytes starting with the given hash, and return the result.
* This is used to compute the hash across strings represented as a set of pieces by allowing the
* hash computation to be continued from piece to piece.
*
* @param h starting hash value
* @param offset offset into this value to start looking at data values
* @param length number of data values to include in the hash computation
* @return ending hash value
*/
protected abstract int partialHash(int h, int offset, int length);
/**
* Checks that the given index falls within the specified array size.
*
* @param index the index position to be tested
* @param size the length of the array
* @throws IndexOutOfBoundsException if the index does not fall within the array.
*/
static void checkIndex(int index, int size) {
if ((index | (size - (index + 1))) < 0) {
if (index < 0) {
throw new ArrayIndexOutOfBoundsException("Index < 0: " + index);
}
throw new ArrayIndexOutOfBoundsException("Index > length: " + index + ", " + size);
}
}
/**
* Checks that the given range falls within the bounds of an array
*
* @param startIndex the start index of the range (inclusive)
* @param endIndex the end index of the range (exclusive)
* @param size the size of the array.
* @return the length of the range.
* @throws IndexOutOfBoundsException some or all of the range falls outside of the array.
*/
static int checkRange(int startIndex, int endIndex, int size) {
final int length = endIndex - startIndex;
if ((startIndex | endIndex | length | (size - endIndex)) < 0) {
if (startIndex < 0) {
throw new IndexOutOfBoundsException("Beginning index: " + startIndex + " < 0");
}
if (endIndex < startIndex) {
throw new IndexOutOfBoundsException(
"Beginning index larger than ending index: " + startIndex + ", " + endIndex);
}
// endIndex >= size
throw new IndexOutOfBoundsException("End index: " + endIndex + " >= " + size);
}
return length;
}
@Override
public final String toString() {
return String.format(
Locale.ROOT,
"<ByteString@%s size=%d contents=\"%s\">",
toHexString(identityHashCode(this)),
size(),
truncateAndEscapeForDisplay());
}
private String truncateAndEscapeForDisplay() {
final int limit = 50;
return size() <= limit ? escapeBytes(this) : escapeBytes(substring(0, limit - 3)) + "...";
}
/**
* 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)
*/
// Keep this class private to avoid deadlocks in classloading across threads as ByteString's
// static initializer loads LiteralByteString and another thread loads LiteralByteString.
private static class LiteralByteString extends ByteString.LeafByteString {
private static final long serialVersionUID = 1L;
protected final byte[] bytes;
/**
* Creates a {@code LiteralByteString} backed by the given array, without copying.
*
* @param bytes array to wrap
*/
LiteralByteString(byte[] bytes) {
if (bytes == null) {
throw new NullPointerException();
}
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
byte internalByteAt(int index) {
return bytes[index];
}
@Override
public int size() {
return bytes.length;
}
// =================================================================
// ByteString -> substring
@Override
public final ByteString substring(int beginIndex, int endIndex) {
final int length = checkRange(beginIndex, endIndex, size());
if (length == 0) {
return ByteString.EMPTY;
}
return new BoundedByteString(bytes, getOffsetIntoBytes() + beginIndex, length);
}
// =================================================================
// 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.
// TODO(nathanmittler): Is not calling getOffsetIntoBytes really saving that much?
System.arraycopy(bytes, sourceOffset, target, targetOffset, numberToCopy);
}
@Override
public final void copyTo(ByteBuffer target) {
target.put(bytes, getOffsetIntoBytes(), size()); // Copies bytes
}
@Override
public final ByteBuffer asReadOnlyByteBuffer() {
return ByteBuffer.wrap(bytes, getOffsetIntoBytes(), size()).asReadOnlyBuffer();
}
@Override
public final List<ByteBuffer> asReadOnlyByteBufferList() {
return Collections.singletonList(asReadOnlyByteBuffer());
}
@Override
public final void writeTo(OutputStream outputStream) throws IOException {
outputStream.write(toByteArray());
}
@Override
final void writeToInternal(OutputStream outputStream, int sourceOffset, int numberToWrite)
throws IOException {
outputStream.write(bytes, getOffsetIntoBytes() + sourceOffset, numberToWrite);
}
@Override
final void writeTo(ByteOutput output) throws IOException {
output.writeLazy(bytes, getOffsetIntoBytes(), size());
}
@Override
protected final String toStringInternal(Charset charset) {
return new String(bytes, getOffsetIntoBytes(), size(), charset);
}
// =================================================================
// UTF-8 decoding
@Override
public final boolean isValidUtf8() {
int offset = getOffsetIntoBytes();
return Utf8.isValidUtf8(bytes, offset, offset + size());
}
@Override
protected final 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 final 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) {
LiteralByteString otherAsLiteral = (LiteralByteString) other;
// If we know the hash codes and they are not equal, we know the byte
// strings are not equal.
int thisHash = peekCachedHashCode();
int thatHash = otherAsLiteral.peekCachedHashCode();
if (thisHash != 0 && thatHash != 0 && thisHash != thatHash) {
return false;
}
return equalsRange((LiteralByteString) other, 0, size());
} else {
// RopeByteString and NioByteString.
return other.equals(this);
}
}
/**
* 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.
*/
@Override
final boolean equalsRange(ByteString 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());
}
if (other instanceof LiteralByteString) {
LiteralByteString lbsOther = (LiteralByteString) other;
byte[] thisBytes = bytes;
byte[] otherBytes = lbsOther.bytes;
int thisLimit = getOffsetIntoBytes() + length;
for (int thisIndex = getOffsetIntoBytes(),
otherIndex = lbsOther.getOffsetIntoBytes() + offset;
(thisIndex < thisLimit);
++thisIndex, ++otherIndex) {
if (thisBytes[thisIndex] != otherBytes[otherIndex]) {
return false;
}
}
return true;
}
return other.substring(offset, offset + length).equals(substring(0, length));
}
@Override
protected final int partialHash(int h, int offset, int length) {
return Internal.partialHash(h, bytes, getOffsetIntoBytes() + offset, length);
}
// =================================================================
// Input stream
@Override
public final InputStream newInput() {
return new ByteArrayInputStream(bytes, getOffsetIntoBytes(), size()); // No copy
}
@Override
public final CodedInputStream newCodedInput() {
// We trust CodedInputStream not to modify the bytes, or to give anyone
// else access to them.
return CodedInputStream.newInstance(
bytes, getOffsetIntoBytes(), size(), /* bufferIsImmutable= */ true);
}
// =================================================================
// Internal methods
/**
* Offset into {@code bytes[]} to use, non-zero for substrings.
*
* @return always 0 for this class
*/
protected int getOffsetIntoBytes() {
return 0;
}
}
/**
* This class is used to represent the substring of a {@link ByteString} over a single byte array.
* In terms of the public API of {@link ByteString}, you end up here by calling {@link
* ByteString#copyFrom(byte[])} followed by {@link ByteString#substring(int, int)}.
*
* <p>This class contains most of the overhead involved in creating a substring from a {@link
* LiteralByteString}. The overhead involves some range-checking and two extra fields.
*
* @author carlanton@google.com (Carl Haverl)
*/
// Keep this class private to avoid deadlocks in classloading across threads as ByteString's
// static initializer loads LiteralByteString and another thread loads BoundedByteString.
private static final class BoundedByteString extends LiteralByteString {
private final int bytesOffset;
private final int bytesLength;
/**
* Creates a {@code BoundedByteString} backed by the sub-range of given array, without copying.
*
* @param bytes array to wrap
* @param offset index to first byte to use in bytes
* @param length number of bytes to use from bytes
* @throws IllegalArgumentException if {@code offset < 0}, {@code length < 0}, or if {@code
* offset + length > bytes.length}.
*/
BoundedByteString(byte[] bytes, int offset, int length) {
super(bytes);
checkRange(offset, offset + length, bytes.length);
this.bytesOffset = offset;
this.bytesLength = length;
}
/**
* Gets the byte at the given index. Throws {@link ArrayIndexOutOfBoundsException} for
* backwards-compatibility reasons although it would more properly be {@link
* IndexOutOfBoundsException}.
*
* @param index index of byte
* @return the value
* @throws ArrayIndexOutOfBoundsException {@code index} is < 0 or >= size
*/
@Override
public byte byteAt(int index) {
// We must check the index ourselves as we cannot rely on Java array index
// checking for substrings.
checkIndex(index, size());
return bytes[bytesOffset + index];
}
@Override
byte internalByteAt(int index) {
return bytes[bytesOffset + index];
}
@Override
public int size() {
return bytesLength;
}
@Override
protected int getOffsetIntoBytes() {
return bytesOffset;
}
// =================================================================
// ByteString -> byte[]
@Override
protected void copyToInternal(
byte[] target, int sourceOffset, int targetOffset, int numberToCopy) {
System.arraycopy(
bytes, getOffsetIntoBytes() + sourceOffset, target, targetOffset, numberToCopy);
}
// =================================================================
// Serializable
private static final long serialVersionUID = 1L;
Object writeReplace() {
return ByteString.wrap(toByteArray());
}
private void readObject(@SuppressWarnings("unused") ObjectInputStream in) throws IOException {
throw new InvalidObjectException(
"BoundedByteStream instances are not to be serialized directly");
}
}
}