| Index: third_party/protobuf/java/src/main/java/com/google/protobuf/RopeByteString.java
|
| diff --git a/third_party/protobuf/java/src/main/java/com/google/protobuf/RopeByteString.java b/third_party/protobuf/java/src/main/java/com/google/protobuf/RopeByteString.java
|
| deleted file mode 100644
|
| index 4699782346935d3a3cde62dd515c1e59d53c40ce..0000000000000000000000000000000000000000
|
| --- a/third_party/protobuf/java/src/main/java/com/google/protobuf/RopeByteString.java
|
| +++ /dev/null
|
| @@ -1,943 +0,0 @@
|
| -// 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.IOException;
|
| -import java.io.InputStream;
|
| -import java.io.OutputStream;
|
| -import java.io.UnsupportedEncodingException;
|
| -import java.io.ByteArrayInputStream;
|
| -import java.nio.ByteBuffer;
|
| -import java.util.ArrayList;
|
| -import java.util.Arrays;
|
| -import java.util.Iterator;
|
| -import java.util.List;
|
| -import java.util.NoSuchElementException;
|
| -import java.util.Stack;
|
| -
|
| -/**
|
| - * Class to represent {@code ByteStrings} formed by concatenation of other
|
| - * ByteStrings, without copying the data in the pieces. The concatenation is
|
| - * represented as a tree whose leaf nodes are each a {@link LiteralByteString}.
|
| - *
|
| - * <p>Most of the operation here is inspired by the now-famous paper <a
|
| - * href="http://www.cs.ubc.ca/local/reading/proceedings/spe91-95/spe/vol25/issue12/spe986.pdf">
|
| - * BAP95 </a> Ropes: an Alternative to Strings hans-j. boehm, russ atkinson and
|
| - * michael plass
|
| - *
|
| - * <p>The algorithms described in the paper have been implemented for character
|
| - * strings in {@link com.google.common.string.Rope} and in the c++ class {@code
|
| - * cord.cc}.
|
| - *
|
| - * <p>Fundamentally the Rope algorithm represents the collection of pieces as a
|
| - * binary tree. BAP95 uses a Fibonacci bound relating depth to a minimum
|
| - * sequence length, sequences that are too short relative to their depth cause a
|
| - * tree rebalance. More precisely, a tree of depth d is "balanced" in the
|
| - * terminology of BAP95 if its length is at least F(d+2), where F(n) is the
|
| - * n-the Fibonacci number. Thus for depths 0, 1, 2, 3, 4, 5,... we have minimum
|
| - * lengths 1, 2, 3, 5, 8, 13,...
|
| - *
|
| - * @author carlanton@google.com (Carl Haverl)
|
| - */
|
| -class RopeByteString extends ByteString {
|
| -
|
| - /**
|
| - * BAP95. Let Fn be the nth Fibonacci number. A {@link RopeByteString} of
|
| - * depth n is "balanced", i.e flat enough, if its length is at least Fn+2,
|
| - * e.g. a "balanced" {@link RopeByteString} of depth 1 must have length at
|
| - * least 2, of depth 4 must have length >= 8, etc.
|
| - *
|
| - * <p>There's nothing special about using the Fibonacci numbers for this, but
|
| - * they are a reasonable sequence for encapsulating the idea that we are OK
|
| - * with longer strings being encoded in deeper binary trees.
|
| - *
|
| - * <p>For 32-bit integers, this array has length 46.
|
| - */
|
| - private static final int[] minLengthByDepth;
|
| -
|
| - static {
|
| - // Dynamically generate the list of Fibonacci numbers the first time this
|
| - // class is accessed.
|
| - List<Integer> numbers = new ArrayList<Integer>();
|
| -
|
| - // we skip the first Fibonacci number (1). So instead of: 1 1 2 3 5 8 ...
|
| - // we have: 1 2 3 5 8 ...
|
| - int f1 = 1;
|
| - int f2 = 1;
|
| -
|
| - // get all the values until we roll over.
|
| - while (f2 > 0) {
|
| - numbers.add(f2);
|
| - int temp = f1 + f2;
|
| - f1 = f2;
|
| - f2 = temp;
|
| - }
|
| -
|
| - // we include this here so that we can index this array to [x + 1] in the
|
| - // loops below.
|
| - numbers.add(Integer.MAX_VALUE);
|
| - minLengthByDepth = new int[numbers.size()];
|
| - for (int i = 0; i < minLengthByDepth.length; i++) {
|
| - // unbox all the values
|
| - minLengthByDepth[i] = numbers.get(i);
|
| - }
|
| - }
|
| -
|
| - private final int totalLength;
|
| - private final ByteString left;
|
| - private final ByteString right;
|
| - private final int leftLength;
|
| - private final int treeDepth;
|
| -
|
| - /**
|
| - * Create a new RopeByteString, which can be thought of as a new tree node, by
|
| - * recording references to the two given strings.
|
| - *
|
| - * @param left string on the left of this node, should have {@code size() >
|
| - * 0}
|
| - * @param right string on the right of this node, should have {@code size() >
|
| - * 0}
|
| - */
|
| - private RopeByteString(ByteString left, ByteString right) {
|
| - this.left = left;
|
| - this.right = right;
|
| - leftLength = left.size();
|
| - totalLength = leftLength + right.size();
|
| - treeDepth = Math.max(left.getTreeDepth(), right.getTreeDepth()) + 1;
|
| - }
|
| -
|
| - /**
|
| - * Concatenate the given strings while performing various optimizations to
|
| - * slow the growth rate of tree depth and tree node count. The result is
|
| - * either a {@link LiteralByteString} or a {@link RopeByteString}
|
| - * depending on which optimizations, if any, were applied.
|
| - *
|
| - * <p>Small pieces of length less than {@link
|
| - * ByteString#CONCATENATE_BY_COPY_SIZE} may be copied by value here, as in
|
| - * BAP95. Large pieces are referenced without copy.
|
| - *
|
| - * @param left string on the left
|
| - * @param right string on the right
|
| - * @return concatenation representing the same sequence as the given strings
|
| - */
|
| - static ByteString concatenate(ByteString left, ByteString right) {
|
| - ByteString result;
|
| - RopeByteString leftRope =
|
| - (left instanceof RopeByteString) ? (RopeByteString) left : null;
|
| - if (right.size() == 0) {
|
| - result = left;
|
| - } else if (left.size() == 0) {
|
| - result = right;
|
| - } else {
|
| - int newLength = left.size() + right.size();
|
| - if (newLength < ByteString.CONCATENATE_BY_COPY_SIZE) {
|
| - // Optimization from BAP95: For short (leaves in paper, but just short
|
| - // here) total length, do a copy of data to a new leaf.
|
| - result = concatenateBytes(left, right);
|
| - } else if (leftRope != null
|
| - && leftRope.right.size() + right.size() < CONCATENATE_BY_COPY_SIZE) {
|
| - // Optimization from BAP95: As an optimization of the case where the
|
| - // ByteString is constructed by repeated concatenate, recognize the case
|
| - // where a short string is concatenated to a left-hand node whose
|
| - // right-hand branch is short. In the paper this applies to leaves, but
|
| - // we just look at the length here. This has the advantage of shedding
|
| - // references to unneeded data when substrings have been taken.
|
| - //
|
| - // When we recognize this case, we do a copy of the data and create a
|
| - // new parent node so that the depth of the result is the same as the
|
| - // given left tree.
|
| - ByteString newRight = concatenateBytes(leftRope.right, right);
|
| - result = new RopeByteString(leftRope.left, newRight);
|
| - } else if (leftRope != null
|
| - && leftRope.left.getTreeDepth() > leftRope.right.getTreeDepth()
|
| - && leftRope.getTreeDepth() > right.getTreeDepth()) {
|
| - // Typically for concatenate-built strings the left-side is deeper than
|
| - // the right. This is our final attempt to concatenate without
|
| - // increasing the tree depth. We'll redo the the node on the RHS. This
|
| - // is yet another optimization for building the string by repeatedly
|
| - // concatenating on the right.
|
| - ByteString newRight = new RopeByteString(leftRope.right, right);
|
| - result = new RopeByteString(leftRope.left, newRight);
|
| - } else {
|
| - // Fine, we'll add a node and increase the tree depth--unless we
|
| - // rebalance ;^)
|
| - int newDepth = Math.max(left.getTreeDepth(), right.getTreeDepth()) + 1;
|
| - if (newLength >= minLengthByDepth[newDepth]) {
|
| - // The tree is shallow enough, so don't rebalance
|
| - result = new RopeByteString(left, right);
|
| - } else {
|
| - result = new Balancer().balance(left, right);
|
| - }
|
| - }
|
| - }
|
| - return result;
|
| - }
|
| -
|
| - /**
|
| - * Concatenates two strings by copying data values. This is called in a few
|
| - * cases in order to reduce the growth of the number of tree nodes.
|
| - *
|
| - * @param left string on the left
|
| - * @param right string on the right
|
| - * @return string formed by copying data bytes
|
| - */
|
| - private static LiteralByteString concatenateBytes(ByteString left,
|
| - ByteString right) {
|
| - int leftSize = left.size();
|
| - int rightSize = right.size();
|
| - byte[] bytes = new byte[leftSize + rightSize];
|
| - left.copyTo(bytes, 0, 0, leftSize);
|
| - right.copyTo(bytes, 0, leftSize, rightSize);
|
| - return new LiteralByteString(bytes); // Constructor wraps bytes
|
| - }
|
| -
|
| - /**
|
| - * Create a new RopeByteString for testing only while bypassing all the
|
| - * defenses of {@link #concatenate(ByteString, ByteString)}. This allows
|
| - * testing trees of specific structure. We are also able to insert empty
|
| - * leaves, though these are dis-allowed, so that we can make sure the
|
| - * implementation can withstand their presence.
|
| - *
|
| - * @param left string on the left of this node
|
| - * @param right string on the right of this node
|
| - * @return an unsafe instance for testing only
|
| - */
|
| - static RopeByteString newInstanceForTest(ByteString left, ByteString right) {
|
| - return new RopeByteString(left, right);
|
| - }
|
| -
|
| - /**
|
| - * 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) {
|
| - if (index < 0) {
|
| - throw new ArrayIndexOutOfBoundsException("Index < 0: " + index);
|
| - }
|
| - if (index > totalLength) {
|
| - throw new ArrayIndexOutOfBoundsException(
|
| - "Index > length: " + index + ", " + totalLength);
|
| - }
|
| -
|
| - byte result;
|
| - // Find the relevant piece by recursive descent
|
| - if (index < leftLength) {
|
| - result = left.byteAt(index);
|
| - } else {
|
| - result = right.byteAt(index - leftLength);
|
| - }
|
| - return result;
|
| - }
|
| -
|
| - @Override
|
| - public int size() {
|
| - return totalLength;
|
| - }
|
| -
|
| - // =================================================================
|
| - // Pieces
|
| -
|
| - @Override
|
| - protected int getTreeDepth() {
|
| - return treeDepth;
|
| - }
|
| -
|
| - /**
|
| - * Determines if the tree is balanced according to BAP95, which means the tree
|
| - * is flat-enough with respect to the bounds. Note that this definition of
|
| - * balanced is one where sub-trees of balanced trees are not necessarily
|
| - * balanced.
|
| - *
|
| - * @return true if the tree is balanced
|
| - */
|
| - @Override
|
| - protected boolean isBalanced() {
|
| - return totalLength >= minLengthByDepth[treeDepth];
|
| - }
|
| -
|
| - /**
|
| - * Takes a substring of this one. This involves recursive descent along the
|
| - * left and right edges of the substring, and referencing any wholly contained
|
| - * segments in between. Any leaf nodes entirely uninvolved in the substring
|
| - * will not be referenced by the substring.
|
| - *
|
| - * <p>Substrings of {@code length < 2} should result in at most a single
|
| - * recursive call chain, terminating at a leaf node. Thus the result will be a
|
| - * {@link LiteralByteString}. {@link #RopeByteString(ByteString,
|
| - * ByteString)}.
|
| - *
|
| - * @param beginIndex start at this index
|
| - * @param endIndex the last character is the one before this index
|
| - * @return substring leaf node or tree
|
| - */
|
| - @Override
|
| - public ByteString substring(int beginIndex, int endIndex) {
|
| - if (beginIndex < 0) {
|
| - throw new IndexOutOfBoundsException(
|
| - "Beginning index: " + beginIndex + " < 0");
|
| - }
|
| - if (endIndex > totalLength) {
|
| - throw new IndexOutOfBoundsException(
|
| - "End index: " + endIndex + " > " + totalLength);
|
| - }
|
| - int substringLength = endIndex - beginIndex;
|
| - if (substringLength < 0) {
|
| - throw new IndexOutOfBoundsException(
|
| - "Beginning index larger than ending index: " + beginIndex + ", "
|
| - + endIndex);
|
| - }
|
| -
|
| - ByteString result;
|
| - if (substringLength == 0) {
|
| - // Empty substring
|
| - result = ByteString.EMPTY;
|
| - } else if (substringLength == totalLength) {
|
| - // The whole string
|
| - result = this;
|
| - } else {
|
| - // Proper substring
|
| - if (endIndex <= leftLength) {
|
| - // Substring on the left
|
| - result = left.substring(beginIndex, endIndex);
|
| - } else if (beginIndex >= leftLength) {
|
| - // Substring on the right
|
| - result = right
|
| - .substring(beginIndex - leftLength, endIndex - leftLength);
|
| - } else {
|
| - // Split substring
|
| - ByteString leftSub = left.substring(beginIndex);
|
| - ByteString rightSub = right.substring(0, endIndex - leftLength);
|
| - // Intentionally not rebalancing, since in many cases these two
|
| - // substrings will already be less deep than the top-level
|
| - // RopeByteString we're taking a substring of.
|
| - result = new RopeByteString(leftSub, rightSub);
|
| - }
|
| - }
|
| - return result;
|
| - }
|
| -
|
| - // =================================================================
|
| - // ByteString -> byte[]
|
| -
|
| - @Override
|
| - protected void copyToInternal(byte[] target, int sourceOffset,
|
| - int targetOffset, int numberToCopy) {
|
| - if (sourceOffset + numberToCopy <= leftLength) {
|
| - left.copyToInternal(target, sourceOffset, targetOffset, numberToCopy);
|
| - } else if (sourceOffset >= leftLength) {
|
| - right.copyToInternal(target, sourceOffset - leftLength, targetOffset,
|
| - numberToCopy);
|
| - } else {
|
| - int leftLength = this.leftLength - sourceOffset;
|
| - left.copyToInternal(target, sourceOffset, targetOffset, leftLength);
|
| - right.copyToInternal(target, 0, targetOffset + leftLength,
|
| - numberToCopy - leftLength);
|
| - }
|
| - }
|
| -
|
| - @Override
|
| - public void copyTo(ByteBuffer target) {
|
| - left.copyTo(target);
|
| - right.copyTo(target);
|
| - }
|
| -
|
| - @Override
|
| - public ByteBuffer asReadOnlyByteBuffer() {
|
| - ByteBuffer byteBuffer = ByteBuffer.wrap(toByteArray());
|
| - return byteBuffer.asReadOnlyBuffer();
|
| - }
|
| -
|
| - @Override
|
| - public List<ByteBuffer> asReadOnlyByteBufferList() {
|
| - // Walk through the list of LiteralByteString's that make up this
|
| - // rope, and add each one as a read-only ByteBuffer.
|
| - List<ByteBuffer> result = new ArrayList<ByteBuffer>();
|
| - PieceIterator pieces = new PieceIterator(this);
|
| - while (pieces.hasNext()) {
|
| - LiteralByteString byteString = pieces.next();
|
| - result.add(byteString.asReadOnlyByteBuffer());
|
| - }
|
| - return result;
|
| - }
|
| -
|
| - @Override
|
| - public void writeTo(OutputStream outputStream) throws IOException {
|
| - left.writeTo(outputStream);
|
| - right.writeTo(outputStream);
|
| - }
|
| -
|
| - @Override
|
| - public String toString(String charsetName)
|
| - throws UnsupportedEncodingException {
|
| - return new String(toByteArray(), charsetName);
|
| - }
|
| -
|
| - // =================================================================
|
| - // UTF-8 decoding
|
| -
|
| - @Override
|
| - public boolean isValidUtf8() {
|
| - int leftPartial = left.partialIsValidUtf8(Utf8.COMPLETE, 0, leftLength);
|
| - int state = right.partialIsValidUtf8(leftPartial, 0, right.size());
|
| - return state == Utf8.COMPLETE;
|
| - }
|
| -
|
| - @Override
|
| - protected int partialIsValidUtf8(int state, int offset, int length) {
|
| - int toIndex = offset + length;
|
| - if (toIndex <= leftLength) {
|
| - return left.partialIsValidUtf8(state, offset, length);
|
| - } else if (offset >= leftLength) {
|
| - return right.partialIsValidUtf8(state, offset - leftLength, length);
|
| - } else {
|
| - int leftLength = this.leftLength - offset;
|
| - int leftPartial = left.partialIsValidUtf8(state, offset, leftLength);
|
| - return right.partialIsValidUtf8(leftPartial, 0, length - leftLength);
|
| - }
|
| - }
|
| -
|
| - // =================================================================
|
| - // equals() and hashCode()
|
| -
|
| - @Override
|
| - public boolean equals(Object other) {
|
| - if (other == this) {
|
| - return true;
|
| - }
|
| - if (!(other instanceof ByteString)) {
|
| - return false;
|
| - }
|
| -
|
| - ByteString otherByteString = (ByteString) other;
|
| - if (totalLength != otherByteString.size()) {
|
| - return false;
|
| - }
|
| - if (totalLength == 0) {
|
| - return true;
|
| - }
|
| -
|
| - // You don't really want to be calling equals on long strings, but since
|
| - // we cache the hashCode, we effectively cache inequality. We use the cached
|
| - // hashCode if it's already computed. It's arguable we should compute the
|
| - // hashCode here, and if we're going to be testing a bunch of byteStrings,
|
| - // it might even make sense.
|
| - if (hash != 0) {
|
| - int cachedOtherHash = otherByteString.peekCachedHashCode();
|
| - if (cachedOtherHash != 0 && hash != cachedOtherHash) {
|
| - return false;
|
| - }
|
| - }
|
| -
|
| - return equalsFragments(otherByteString);
|
| - }
|
| -
|
| - /**
|
| - * Determines if this string is equal to another of the same length by
|
| - * iterating over the leaf nodes. On each step of the iteration, the
|
| - * overlapping segments of the leaves are compared.
|
| - *
|
| - * @param other string of the same length as this one
|
| - * @return true if the values of this string equals the value of the given
|
| - * one
|
| - */
|
| - private boolean equalsFragments(ByteString other) {
|
| - int thisOffset = 0;
|
| - Iterator<LiteralByteString> thisIter = new PieceIterator(this);
|
| - LiteralByteString thisString = thisIter.next();
|
| -
|
| - int thatOffset = 0;
|
| - Iterator<LiteralByteString> thatIter = new PieceIterator(other);
|
| - LiteralByteString thatString = thatIter.next();
|
| -
|
| - int pos = 0;
|
| - while (true) {
|
| - int thisRemaining = thisString.size() - thisOffset;
|
| - int thatRemaining = thatString.size() - thatOffset;
|
| - int bytesToCompare = Math.min(thisRemaining, thatRemaining);
|
| -
|
| - // At least one of the offsets will be zero
|
| - boolean stillEqual = (thisOffset == 0)
|
| - ? thisString.equalsRange(thatString, thatOffset, bytesToCompare)
|
| - : thatString.equalsRange(thisString, thisOffset, bytesToCompare);
|
| - if (!stillEqual) {
|
| - return false;
|
| - }
|
| -
|
| - pos += bytesToCompare;
|
| - if (pos >= totalLength) {
|
| - if (pos == totalLength) {
|
| - return true;
|
| - }
|
| - throw new IllegalStateException();
|
| - }
|
| - // We always get to the end of at least one of the pieces
|
| - if (bytesToCompare == thisRemaining) { // If reached end of this
|
| - thisOffset = 0;
|
| - thisString = thisIter.next();
|
| - } else {
|
| - thisOffset += bytesToCompare;
|
| - }
|
| - if (bytesToCompare == thatRemaining) { // If reached end of that
|
| - thatOffset = 0;
|
| - thatString = thatIter.next();
|
| - } else {
|
| - thatOffset += bytesToCompare;
|
| - }
|
| - }
|
| - }
|
| -
|
| - /**
|
| - * 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;
|
| -
|
| - @Override
|
| - public int hashCode() {
|
| - int h = hash;
|
| -
|
| - if (h == 0) {
|
| - h = totalLength;
|
| - h = partialHash(h, 0, totalLength);
|
| - 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) {
|
| - int toIndex = offset + length;
|
| - if (toIndex <= leftLength) {
|
| - return left.partialHash(h, offset, length);
|
| - } else if (offset >= leftLength) {
|
| - return right.partialHash(h, offset - leftLength, length);
|
| - } else {
|
| - int leftLength = this.leftLength - offset;
|
| - int leftPartial = left.partialHash(h, offset, leftLength);
|
| - return right.partialHash(leftPartial, 0, length - leftLength);
|
| - }
|
| - }
|
| -
|
| - // =================================================================
|
| - // Input stream
|
| -
|
| - @Override
|
| - public CodedInputStream newCodedInput() {
|
| - return CodedInputStream.newInstance(new RopeInputStream());
|
| - }
|
| -
|
| - @Override
|
| - public InputStream newInput() {
|
| - return new RopeInputStream();
|
| - }
|
| -
|
| - /**
|
| - * This class implements the balancing algorithm of BAP95. In the paper the
|
| - * authors use an array to keep track of pieces, while here we use a stack.
|
| - * The tree is balanced by traversing subtrees in left to right order, and the
|
| - * stack always contains the part of the string we've traversed so far.
|
| - *
|
| - * <p>One surprising aspect of the algorithm is the result of balancing is not
|
| - * necessarily balanced, though it is nearly balanced. For details, see
|
| - * BAP95.
|
| - */
|
| - private static class Balancer {
|
| - // Stack containing the part of the string, starting from the left, that
|
| - // we've already traversed. The final string should be the equivalent of
|
| - // concatenating the strings on the stack from bottom to top.
|
| - private final Stack<ByteString> prefixesStack = new Stack<ByteString>();
|
| -
|
| - private ByteString balance(ByteString left, ByteString right) {
|
| - doBalance(left);
|
| - doBalance(right);
|
| -
|
| - // Sweep stack to gather the result
|
| - ByteString partialString = prefixesStack.pop();
|
| - while (!prefixesStack.isEmpty()) {
|
| - ByteString newLeft = prefixesStack.pop();
|
| - partialString = new RopeByteString(newLeft, partialString);
|
| - }
|
| - // We should end up with a RopeByteString since at a minimum we will
|
| - // create one from concatenating left and right
|
| - return partialString;
|
| - }
|
| -
|
| - private void doBalance(ByteString root) {
|
| - // BAP95: Insert balanced subtrees whole. This means the result might not
|
| - // be balanced, leading to repeated rebalancings on concatenate. However,
|
| - // these rebalancings are shallow due to ignoring balanced subtrees, and
|
| - // relatively few calls to insert() result.
|
| - if (root.isBalanced()) {
|
| - insert(root);
|
| - } else if (root instanceof RopeByteString) {
|
| - RopeByteString rbs = (RopeByteString) root;
|
| - doBalance(rbs.left);
|
| - doBalance(rbs.right);
|
| - } else {
|
| - throw new IllegalArgumentException(
|
| - "Has a new type of ByteString been created? Found " +
|
| - root.getClass());
|
| - }
|
| - }
|
| -
|
| - /**
|
| - * Push a string on the balance stack (BAP95). BAP95 uses an array and
|
| - * calls the elements in the array 'bins'. We instead use a stack, so the
|
| - * 'bins' of lengths are represented by differences between the elements of
|
| - * minLengthByDepth.
|
| - *
|
| - * <p>If the length bin for our string, and all shorter length bins, are
|
| - * empty, we just push it on the stack. Otherwise, we need to start
|
| - * concatenating, putting the given string in the "middle" and continuing
|
| - * until we land in an empty length bin that matches the length of our
|
| - * concatenation.
|
| - *
|
| - * @param byteString string to place on the balance stack
|
| - */
|
| - private void insert(ByteString byteString) {
|
| - int depthBin = getDepthBinForLength(byteString.size());
|
| - int binEnd = minLengthByDepth[depthBin + 1];
|
| -
|
| - // BAP95: Concatenate all trees occupying bins representing the length of
|
| - // our new piece or of shorter pieces, to the extent that is possible.
|
| - // The goal is to clear the bin which our piece belongs in, but that may
|
| - // not be entirely possible if there aren't enough longer bins occupied.
|
| - if (prefixesStack.isEmpty() || prefixesStack.peek().size() >= binEnd) {
|
| - prefixesStack.push(byteString);
|
| - } else {
|
| - int binStart = minLengthByDepth[depthBin];
|
| -
|
| - // Concatenate the subtrees of shorter length
|
| - ByteString newTree = prefixesStack.pop();
|
| - while (!prefixesStack.isEmpty()
|
| - && prefixesStack.peek().size() < binStart) {
|
| - ByteString left = prefixesStack.pop();
|
| - newTree = new RopeByteString(left, newTree);
|
| - }
|
| -
|
| - // Concatenate the given string
|
| - newTree = new RopeByteString(newTree, byteString);
|
| -
|
| - // Continue concatenating until we land in an empty bin
|
| - while (!prefixesStack.isEmpty()) {
|
| - depthBin = getDepthBinForLength(newTree.size());
|
| - binEnd = minLengthByDepth[depthBin + 1];
|
| - if (prefixesStack.peek().size() < binEnd) {
|
| - ByteString left = prefixesStack.pop();
|
| - newTree = new RopeByteString(left, newTree);
|
| - } else {
|
| - break;
|
| - }
|
| - }
|
| - prefixesStack.push(newTree);
|
| - }
|
| - }
|
| -
|
| - private int getDepthBinForLength(int length) {
|
| - int depth = Arrays.binarySearch(minLengthByDepth, length);
|
| - if (depth < 0) {
|
| - // It wasn't an exact match, so convert to the index of the containing
|
| - // fragment, which is one less even than the insertion point.
|
| - int insertionPoint = -(depth + 1);
|
| - depth = insertionPoint - 1;
|
| - }
|
| -
|
| - return depth;
|
| - }
|
| - }
|
| -
|
| - /**
|
| - * This class is a continuable tree traversal, which keeps the state
|
| - * information which would exist on the stack in a recursive traversal instead
|
| - * on a stack of "Bread Crumbs". The maximum depth of the stack in this
|
| - * iterator is the same as the depth of the tree being traversed.
|
| - *
|
| - * <p>This iterator is used to implement
|
| - * {@link RopeByteString#equalsFragments(ByteString)}.
|
| - */
|
| - private static class PieceIterator implements Iterator<LiteralByteString> {
|
| -
|
| - private final Stack<RopeByteString> breadCrumbs =
|
| - new Stack<RopeByteString>();
|
| - private LiteralByteString next;
|
| -
|
| - private PieceIterator(ByteString root) {
|
| - next = getLeafByLeft(root);
|
| - }
|
| -
|
| - private LiteralByteString getLeafByLeft(ByteString root) {
|
| - ByteString pos = root;
|
| - while (pos instanceof RopeByteString) {
|
| - RopeByteString rbs = (RopeByteString) pos;
|
| - breadCrumbs.push(rbs);
|
| - pos = rbs.left;
|
| - }
|
| - return (LiteralByteString) pos;
|
| - }
|
| -
|
| - private LiteralByteString getNextNonEmptyLeaf() {
|
| - while (true) {
|
| - // Almost always, we go through this loop exactly once. However, if
|
| - // we discover an empty string in the rope, we toss it and try again.
|
| - if (breadCrumbs.isEmpty()) {
|
| - return null;
|
| - } else {
|
| - LiteralByteString result = getLeafByLeft(breadCrumbs.pop().right);
|
| - if (!result.isEmpty()) {
|
| - return result;
|
| - }
|
| - }
|
| - }
|
| - }
|
| -
|
| - public boolean hasNext() {
|
| - return next != null;
|
| - }
|
| -
|
| - /**
|
| - * Returns the next item and advances one {@code LiteralByteString}.
|
| - *
|
| - * @return next non-empty LiteralByteString or {@code null}
|
| - */
|
| - public LiteralByteString next() {
|
| - if (next == null) {
|
| - throw new NoSuchElementException();
|
| - }
|
| - LiteralByteString result = next;
|
| - next = getNextNonEmptyLeaf();
|
| - return result;
|
| - }
|
| -
|
| - public void remove() {
|
| - throw new UnsupportedOperationException();
|
| - }
|
| - }
|
| -
|
| - // =================================================================
|
| - // ByteIterator
|
| -
|
| - @Override
|
| - public ByteIterator iterator() {
|
| - return new RopeByteIterator();
|
| - }
|
| -
|
| - private class RopeByteIterator implements ByteString.ByteIterator {
|
| -
|
| - private final PieceIterator pieces;
|
| - private ByteIterator bytes;
|
| - int bytesRemaining;
|
| -
|
| - private RopeByteIterator() {
|
| - pieces = new PieceIterator(RopeByteString.this);
|
| - bytes = pieces.next().iterator();
|
| - bytesRemaining = size();
|
| - }
|
| -
|
| - public boolean hasNext() {
|
| - return (bytesRemaining > 0);
|
| - }
|
| -
|
| - public Byte next() {
|
| - return nextByte(); // Does not instantiate a Byte
|
| - }
|
| -
|
| - public byte nextByte() {
|
| - if (!bytes.hasNext()) {
|
| - bytes = pieces.next().iterator();
|
| - }
|
| - --bytesRemaining;
|
| - return bytes.nextByte();
|
| - }
|
| -
|
| - public void remove() {
|
| - throw new UnsupportedOperationException();
|
| - }
|
| - }
|
| -
|
| - /**
|
| - * This class is the {@link RopeByteString} equivalent for
|
| - * {@link ByteArrayInputStream}.
|
| - */
|
| - private class RopeInputStream extends InputStream {
|
| - // Iterates through the pieces of the rope
|
| - private PieceIterator pieceIterator;
|
| - // The current piece
|
| - private LiteralByteString currentPiece;
|
| - // The size of the current piece
|
| - private int currentPieceSize;
|
| - // The index of the next byte to read in the current piece
|
| - private int currentPieceIndex;
|
| - // The offset of the start of the current piece in the rope byte string
|
| - private int currentPieceOffsetInRope;
|
| - // Offset in the buffer at which user called mark();
|
| - private int mark;
|
| -
|
| - public RopeInputStream() {
|
| - initialize();
|
| - }
|
| -
|
| - @Override
|
| - public int read(byte b[], int offset, int length) {
|
| - if (b == null) {
|
| - throw new NullPointerException();
|
| - } else if (offset < 0 || length < 0 || length > b.length - offset) {
|
| - throw new IndexOutOfBoundsException();
|
| - }
|
| - return readSkipInternal(b, offset, length);
|
| - }
|
| -
|
| - @Override
|
| - public long skip(long length) {
|
| - if (length < 0) {
|
| - throw new IndexOutOfBoundsException();
|
| - } else if (length > Integer.MAX_VALUE) {
|
| - length = Integer.MAX_VALUE;
|
| - }
|
| - return readSkipInternal(null, 0, (int) length);
|
| - }
|
| -
|
| - /**
|
| - * Internal implementation of read and skip. If b != null, then read the
|
| - * next {@code length} bytes into the buffer {@code b} at
|
| - * offset {@code offset}. If b == null, then skip the next {@code length)
|
| - * bytes.
|
| - * <p>
|
| - * This method assumes that all error checking has already happened.
|
| - * <p>
|
| - * Returns the actual number of bytes read or skipped.
|
| - */
|
| - private int readSkipInternal(byte b[], int offset, int length) {
|
| - int bytesRemaining = length;
|
| - while (bytesRemaining > 0) {
|
| - advanceIfCurrentPieceFullyRead();
|
| - if (currentPiece == null) {
|
| - if (bytesRemaining == length) {
|
| - // We didn't manage to read anything
|
| - return -1;
|
| - }
|
| - break;
|
| - } else {
|
| - // Copy the bytes from this piece.
|
| - int currentPieceRemaining = currentPieceSize - currentPieceIndex;
|
| - int count = Math.min(currentPieceRemaining, bytesRemaining);
|
| - if (b != null) {
|
| - currentPiece.copyTo(b, currentPieceIndex, offset, count);
|
| - offset += count;
|
| - }
|
| - currentPieceIndex += count;
|
| - bytesRemaining -= count;
|
| - }
|
| - }
|
| - // Return the number of bytes read.
|
| - return length - bytesRemaining;
|
| - }
|
| -
|
| - @Override
|
| - public int read() throws IOException {
|
| - advanceIfCurrentPieceFullyRead();
|
| - if (currentPiece == null) {
|
| - return -1;
|
| - } else {
|
| - return currentPiece.byteAt(currentPieceIndex++) & 0xFF;
|
| - }
|
| - }
|
| -
|
| - @Override
|
| - public int available() throws IOException {
|
| - int bytesRead = currentPieceOffsetInRope + currentPieceIndex;
|
| - return RopeByteString.this.size() - bytesRead;
|
| - }
|
| -
|
| - @Override
|
| - public boolean markSupported() {
|
| - return true;
|
| - }
|
| -
|
| - @Override
|
| - public void mark(int readAheadLimit) {
|
| - // Set the mark to our position in the byte string
|
| - mark = currentPieceOffsetInRope + currentPieceIndex;
|
| - }
|
| -
|
| - @Override
|
| - public synchronized void reset() {
|
| - // Just reinitialize and skip the specified number of bytes.
|
| - initialize();
|
| - readSkipInternal(null, 0, mark);
|
| - }
|
| -
|
| - /** Common initialization code used by both the constructor and reset() */
|
| - private void initialize() {
|
| - pieceIterator = new PieceIterator(RopeByteString.this);
|
| - currentPiece = pieceIterator.next();
|
| - currentPieceSize = currentPiece.size();
|
| - currentPieceIndex = 0;
|
| - currentPieceOffsetInRope = 0;
|
| - }
|
| -
|
| - /**
|
| - * Skips to the next piece if we have read all the data in the current
|
| - * piece. Sets currentPiece to null if we have reached the end of the
|
| - * input.
|
| - */
|
| - private void advanceIfCurrentPieceFullyRead() {
|
| - if (currentPiece != null && currentPieceIndex == currentPieceSize) {
|
| - // Generally, we can only go through this loop at most once, since
|
| - // empty strings can't end up in a rope. But better to test.
|
| - currentPieceOffsetInRope += currentPieceSize;
|
| - currentPieceIndex = 0;
|
| - if (pieceIterator.hasNext()) {
|
| - currentPiece = pieceIterator.next();
|
| - currentPieceSize = currentPiece.size();
|
| - } else {
|
| - currentPiece = null;
|
| - currentPieceSize = 0;
|
| - }
|
| - }
|
| - }
|
| - }
|
| -}
|
|
|