diff options
Diffstat (limited to 'java/src/main/java/com/google/protobuf/ByteString.java')
| -rw-r--r-- | java/src/main/java/com/google/protobuf/ByteString.java | 937 |
1 files changed, 153 insertions, 784 deletions
diff --git a/java/src/main/java/com/google/protobuf/ByteString.java b/java/src/main/java/com/google/protobuf/ByteString.java index 7da5612..5fade03 100644 --- a/java/src/main/java/com/google/protobuf/ByteString.java +++ b/java/src/main/java/com/google/protobuf/ByteString.java @@ -1,6 +1,6 @@ // Protocol Buffers - Google's data interchange format // Copyright 2008 Google Inc. All rights reserved. -// https://developers.google.com/protocol-buffers/ +// 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 @@ -30,426 +30,140 @@ package com.google.protobuf; -import java.io.ByteArrayOutputStream; -import java.io.IOException; import java.io.InputStream; -import java.io.OutputStream; +import java.io.ByteArrayInputStream; +import java.io.ByteArrayOutputStream; +import java.io.FilterOutputStream; import java.io.UnsupportedEncodingException; import java.nio.ByteBuffer; -import java.util.ArrayList; -import java.util.Collection; -import java.util.Iterator; import java.util.List; -import java.util.NoSuchElementException; /** - * Immutable sequence of bytes. Substring is supported by sharing the reference - * to the immutable underlying bytes, as with {@link String}. Concatenation is - * likewise supported without copying (long strings) by building a tree of - * pieces in {@link RopeByteString}. - * <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. + * Immutable array of bytes. * * @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> { - - /** - * 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 +public final class ByteString { + private final byte[] bytes; - /** - * Empty {@code ByteString}. - */ - public static final ByteString EMPTY = new LiteralByteString(new byte[0]); - - // This constructor is here to prevent subclassing outside of this package, - ByteString() {} + private ByteString(final byte[] bytes) { + this.bytes = bytes; + } /** - * 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. + * Gets the byte at the given index. * - * @param index index of byte - * @return the value * @throws ArrayIndexOutOfBoundsException {@code index} is < 0 or >= size */ - public abstract byte byteAt(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 - */ - public abstract ByteIterator iterator(); - - /** - * 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(); + public byte byteAt(final int index) { + return bytes[index]; } /** * Gets the number of bytes. - * - * @return size in bytes */ - public abstract int size(); + public int size() { + return bytes.length; + } /** * Returns {@code true} if the size is {@code 0}, {@code false} otherwise. - * - * @return true if this is zero bytes long */ public boolean isEmpty() { - return size() == 0; + return bytes.length == 0; } // ================================================================= - // 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 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 boolean startsWith(ByteString prefix) { - return size() >= prefix.size() && - substring(0, prefix.size()).equals(prefix); - } + // byte[] -> ByteString /** - * 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. + * Empty ByteString. */ - public boolean endsWith(ByteString suffix) { - return size() >= suffix.size() && - substring(size() - suffix.size()).equals(suffix); - } - - // ================================================================= - // byte[] -> ByteString + public static final ByteString EMPTY = new ByteString(new byte[0]); /** * 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} */ - public static ByteString copyFrom(byte[] bytes, int offset, int size) { - byte[] copy = new byte[size]; + public static ByteString copyFrom(final byte[] bytes, final int offset, + final int size) { + final byte[] copy = new byte[size]; System.arraycopy(bytes, offset, copy, 0, size); - return new LiteralByteString(copy); + return new ByteString(copy); } /** * Copies the given bytes into a {@code ByteString}. - * - * @param bytes to copy - * @return new {@code ByteString} */ - public static ByteString copyFrom(byte[] bytes) { + public static ByteString copyFrom(final byte[] bytes) { return copyFrom(bytes, 0, bytes.length); } /** - * Copies the next {@code size} bytes from a {@code java.nio.ByteBuffer} into + * Copies {@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} */ - public static ByteString copyFrom(ByteBuffer bytes, int size) { - byte[] copy = new byte[size]; + public static ByteString copyFrom(final ByteBuffer bytes, final int size) { + final byte[] copy = new byte[size]; bytes.get(copy); - return new LiteralByteString(copy); + return new ByteString(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) { + public static ByteString copyFrom(final 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) + public static ByteString copyFrom(final String text, final String charsetName) throws UnsupportedEncodingException { - return new LiteralByteString(text.getBytes(charsetName)); + return new ByteString(text.getBytes(charsetName)); } /** * 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) { + public static ByteString copyFromUtf8(final String text) { try { - return new LiteralByteString(text.getBytes("UTF-8")); + return new ByteString(text.getBytes("UTF-8")); } catch (UnsupportedEncodingException e) { throw new RuntimeException("UTF-8 not supported?", e); } } - // ================================================================= - // 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. - * - * <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. If the caller knows the precise length of - * the stream and wishes to avoid all unnecessary copies and - * allocations, consider using the two-argument version of this - * method, below. - * - * @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. - * - * <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. In - * particular, if the chunkSize is precisely the same as the length - * of the stream, unnecessary allocations and copies will be - * avoided. Otherwise, the chunks will be of the given size, except - * for the last chunk, which will be resized (via a reallocation and - * copy) to contain the remainder of the stream. - * - * @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; - } else { - 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 ByteString concat(ByteString other) { - int thisSize = size(); - int otherSize = other.size(); - if ((long) thisSize + otherSize >= Integer.MAX_VALUE) { - throw new IllegalArgumentException("ByteString would be too long: " + - thisSize + "+" + otherSize); - } - - 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). + * Concatenates all byte strings in the list and returns the result. * * <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) { - Collection<ByteString> collection; - if (!(byteStrings instanceof Collection)) { - collection = new ArrayList<ByteString>(); - for (ByteString byteString : byteStrings) { - collection.add(byteString); - } - } else { - collection = (Collection<ByteString>) byteStrings; - } - ByteString result; - if (collection.isEmpty()) { - result = EMPTY; - } else { - result = balancedConcat(collection.iterator(), collection.size()); + public static ByteString copyFrom(List<ByteString> list) { + if (list.size() == 0) { + return EMPTY; + } else if (list.size() == 1) { + return list.get(0); } - return result; - } - // 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) { - assert length >= 1; - 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); + int size = 0; + for (ByteString str : list) { + size += str.size(); + } + byte[] bytes = new byte[size]; + int pos = 0; + for (ByteString str : list) { + System.arraycopy(str.bytes, 0, bytes, pos, str.size()); + pos += str.size(); } - return result; + return new ByteString(bytes); } // ================================================================= @@ -460,493 +174,194 @@ public abstract class ByteString implements Iterable<Byte> { * * @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()); + public void copyTo(final byte[] target, final int offset) { + System.arraycopy(bytes, 0, target, offset, bytes.length); } /** * Copies bytes into a buffer. * - * @param target buffer to copy into + * @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 + * @param size number of bytes to copy */ - public void copyTo(byte[] target, int sourceOffset, int targetOffset, - int numberToCopy) { - if (sourceOffset < 0) { - throw new IndexOutOfBoundsException("Source offset < 0: " + sourceOffset); - } - if (targetOffset < 0) { - throw new IndexOutOfBoundsException("Target offset < 0: " + targetOffset); - } - if (numberToCopy < 0) { - throw new IndexOutOfBoundsException("Length < 0: " + numberToCopy); - } - if (sourceOffset + numberToCopy > size()) { - throw new IndexOutOfBoundsException( - "Source end offset < 0: " + (sourceOffset + numberToCopy)); - } - if (targetOffset + numberToCopy > target.length) { - throw new IndexOutOfBoundsException( - "Target end offset < 0: " + (targetOffset + numberToCopy)); - } - if (numberToCopy > 0) { - copyToInternal(target, sourceOffset, targetOffset, numberToCopy); - } + public void copyTo(final byte[] target, final int sourceOffset, + final int targetOffset, + final int size) { + System.arraycopy(bytes, sourceOffset, target, targetOffset, size); } /** - * 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. - * - * @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 byte[] toByteArray() { - int size = size(); - if (size == 0) { - return Internal.EMPTY_BYTE_ARRAY; - } - byte[] result = new byte[size]; - copyToInternal(result, 0, 0, size); - return result; + final int size = bytes.length; + final byte[] copy = new byte[size]; + System.arraycopy(bytes, 0, copy, 0, size); + return copy; } /** - * Writes the complete 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. + * Constructs a new read-only {@code java.nio.ByteBuffer} with the + * same backing byte array. */ - 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 - */ - void writeTo(OutputStream out, int sourceOffset, int numberToWrite) - throws IOException { - if (sourceOffset < 0) { - throw new IndexOutOfBoundsException("Source offset < 0: " + sourceOffset); - } - if (numberToWrite < 0) { - throw new IndexOutOfBoundsException("Length < 0: " + numberToWrite); - } - if (sourceOffset + numberToWrite > size()) { - throw new IndexOutOfBoundsException( - "Source end offset exceeded: " + (sourceOffset + numberToWrite)); - } - if (numberToWrite > 0) { - writeToInternal(out, sourceOffset, numberToWrite); - } - + public ByteBuffer asReadOnlyByteBuffer() { + final ByteBuffer byteBuffer = ByteBuffer.wrap(bytes); + return byteBuffer.asReadOnlyBuffer(); } /** - * 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; - - /** - * 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 abstract String toString(String charsetName) - throws UnsupportedEncodingException; - - // ================================================================= - // UTF-8 decoding + public String toString(final String charsetName) + throws UnsupportedEncodingException { + return new String(bytes, charsetName); + } /** * Constructs a new {@code String} by decoding the bytes as UTF-8. - * - * @return new string using UTF-8 encoding */ public String toStringUtf8() { try { - return toString("UTF-8"); + return new String(bytes, "UTF-8"); } catch (UnsupportedEncodingException e) { throw new RuntimeException("UTF-8 not supported?", e); } } - /** - * 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); + public boolean equals(final Object o) { + if (o == this) { + return true; + } + + if (!(o instanceof ByteString)) { + return false; + } + + final ByteString other = (ByteString) o; + final int size = bytes.length; + if (size != other.bytes.length) { + return false; + } + + final byte[] thisBytes = bytes; + final byte[] otherBytes = other.bytes; + for (int i = 0; i < size; i++) { + if (thisBytes[i] != otherBytes[i]) { + return false; + } + } + + return true; + } + + private volatile int hash = 0; - /** - * Return a non-zero hashCode depending only on the sequence of bytes - * in this ByteString. - * - * @return hashCode value for this object - */ @Override - public abstract int hashCode(); + public int hashCode() { + int h = hash; + + if (h == 0) { + final byte[] thisBytes = bytes; + final int size = bytes.length; + + h = size; + for (int i = 0; i < size; i++) { + h = h * 31 + thisBytes[i]; + } + 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. - * <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(); + public InputStream newInput() { + return new ByteArrayInputStream(bytes); + } /** * 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 + * Using this is more efficient than creating a {@link CodedInputStream} + * wrapping the result of {@link #newInput()}. */ - public abstract CodedInputStream newCodedInput(); + public CodedInputStream newCodedInput() { + // We trust CodedInputStream not to modify the bytes, or to give anyone + // else access to them. + return CodedInputStream.newInstance(bytes); + } // ================================================================= // 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} + * Creates a new {@link Output} with the given initial capacity. */ - public static Output newOutput(int initialCapacity) { - return new Output(initialCapacity); + public static Output newOutput(final int initialCapacity) { + return new Output(new ByteArrayOutputStream(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} + * Creates a new {@link Output}. */ public static Output newOutput() { - return new Output(CONCATENATE_BY_COPY_SIZE); + return newOutput(32); } /** * 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; + public static final class Output extends FilterOutputStream { + private final ByteArrayOutputStream bout; /** - * Creates a new ByteString output stream with the specified - * initial capacity. - * - * @param initialCapacity the initial capacity of the output stream. + * Constructs a new output with the given initial capacity. */ - 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, 0 /* count */, length); - bufferPos = length; - } + private Output(final ByteArrayOutputStream bout) { + super(bout); + this.bout = bout; } /** - * 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. + * Creates a {@code ByteString} instance from this {@code Output}. */ - 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; + public ByteString toByteString() { + final byte[] byteArray = bout.toByteArray(); + return new ByteString(byteArray); } } /** - * 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}. + * Constructs a new 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 + * @param size The target byte size of the {@code ByteString}. You must + * write exactly this many bytes before building the result. */ - static CodedBuilder newCodedBuilder(int size) { + static CodedBuilder newCodedBuilder(final int size) { return new CodedBuilder(size); } @@ -955,7 +370,7 @@ public abstract class ByteString implements Iterable<Byte> { private final CodedOutputStream output; private final byte[] buffer; - private CodedBuilder(int size) { + private CodedBuilder(final int size) { buffer = new byte[size]; output = CodedOutputStream.newInstance(buffer); } @@ -966,57 +381,11 @@ public abstract class ByteString implements Iterable<Byte> { // 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); + return new ByteString(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 abstract int peekCachedHashCode(); - - /** - * 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); - - @Override - public String toString() { - return String.format("<ByteString@%s size=%d>", - Integer.toHexString(System.identityHashCode(this)), size()); - } } |