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Diffstat (limited to 'java/src/main/java/com/google/protobuf/LiteralByteString.java')
-rw-r--r-- | java/src/main/java/com/google/protobuf/LiteralByteString.java | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/java/src/main/java/com/google/protobuf/LiteralByteString.java b/java/src/main/java/com/google/protobuf/LiteralByteString.java new file mode 100644 index 0000000..83e71e9 --- /dev/null +++ b/java/src/main/java/com/google/protobuf/LiteralByteString.java @@ -0,0 +1,362 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. All rights reserved. +// https://developers.google.com/protocol-buffers/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +package com.google.protobuf; + +import java.io.ByteArrayInputStream; +import java.io.IOException; +import java.io.InputStream; +import java.io.OutputStream; +import java.io.UnsupportedEncodingException; +import java.nio.ByteBuffer; +import java.util.ArrayList; +import java.util.List; +import java.util.NoSuchElementException; + +/** + * This class implements a {@link com.google.protobuf.ByteString} backed by a + * single array of bytes, contiguous in memory. It supports substring by + * pointing to only a sub-range of the underlying byte array, meaning that a + * substring will reference the full byte-array of the string it's made from, + * exactly as with {@link String}. + * + * @author carlanton@google.com (Carl Haverl) + */ +class LiteralByteString extends ByteString { + + protected final byte[] bytes; + + /** + * Creates a {@code LiteralByteString} backed by the given array, without + * copying. + * + * @param bytes array to wrap + */ + LiteralByteString(byte[] bytes) { + this.bytes = bytes; + } + + @Override + public byte byteAt(int index) { + // Unlike most methods in this class, this one is a direct implementation + // ignoring the potential offset because we need to do range-checking in the + // substring case anyway. + return bytes[index]; + } + + @Override + public int size() { + return bytes.length; + } + + // ================================================================= + // ByteString -> substring + + @Override + public ByteString substring(int beginIndex, int endIndex) { + if (beginIndex < 0) { + throw new IndexOutOfBoundsException( + "Beginning index: " + beginIndex + " < 0"); + } + if (endIndex > size()) { + throw new IndexOutOfBoundsException("End index: " + endIndex + " > " + + size()); + } + int substringLength = endIndex - beginIndex; + if (substringLength < 0) { + throw new IndexOutOfBoundsException( + "Beginning index larger than ending index: " + beginIndex + ", " + + endIndex); + } + + ByteString result; + if (substringLength == 0) { + result = ByteString.EMPTY; + } else { + result = new BoundedByteString(bytes, getOffsetIntoBytes() + beginIndex, + substringLength); + } + return result; + } + + // ================================================================= + // ByteString -> byte[] + + @Override + protected void copyToInternal(byte[] target, int sourceOffset, + int targetOffset, int numberToCopy) { + // Optimized form, not for subclasses, since we don't call + // getOffsetIntoBytes() or check the 'numberToCopy' parameter. + System.arraycopy(bytes, sourceOffset, target, targetOffset, numberToCopy); + } + + @Override + public void copyTo(ByteBuffer target) { + target.put(bytes, getOffsetIntoBytes(), size()); // Copies bytes + } + + @Override + public ByteBuffer asReadOnlyByteBuffer() { + ByteBuffer byteBuffer = + ByteBuffer.wrap(bytes, getOffsetIntoBytes(), size()); + return byteBuffer.asReadOnlyBuffer(); + } + + @Override + public List<ByteBuffer> asReadOnlyByteBufferList() { + // Return the ByteBuffer generated by asReadOnlyByteBuffer() as a singleton + List<ByteBuffer> result = new ArrayList<ByteBuffer>(1); + result.add(asReadOnlyByteBuffer()); + return result; + } + + @Override + public void writeTo(OutputStream outputStream) throws IOException { + outputStream.write(toByteArray()); + } + + @Override + void writeToInternal(OutputStream outputStream, int sourceOffset, + int numberToWrite) throws IOException { + outputStream.write(bytes, getOffsetIntoBytes() + sourceOffset, + numberToWrite); + } + + @Override + public String toString(String charsetName) + throws UnsupportedEncodingException { + return new String(bytes, getOffsetIntoBytes(), size(), charsetName); + } + + // ================================================================= + // UTF-8 decoding + + @Override + public boolean isValidUtf8() { + int offset = getOffsetIntoBytes(); + return Utf8.isValidUtf8(bytes, offset, offset + size()); + } + + @Override + protected int partialIsValidUtf8(int state, int offset, int length) { + int index = getOffsetIntoBytes() + offset; + return Utf8.partialIsValidUtf8(state, bytes, index, index + length); + } + + // ================================================================= + // equals() and hashCode() + + @Override + public boolean equals(Object other) { + if (other == this) { + return true; + } + if (!(other instanceof ByteString)) { + return false; + } + + if (size() != ((ByteString) other).size()) { + return false; + } + if (size() == 0) { + return true; + } + + if (other instanceof LiteralByteString) { + return equalsRange((LiteralByteString) other, 0, size()); + } else if (other instanceof RopeByteString) { + return other.equals(this); + } else { + throw new IllegalArgumentException( + "Has a new type of ByteString been created? Found " + + other.getClass()); + } + } + + /** + * Check equality of the substring of given length of this object starting at + * zero with another {@code LiteralByteString} substring starting at offset. + * + * @param other what to compare a substring in + * @param offset offset into other + * @param length number of bytes to compare + * @return true for equality of substrings, else false. + */ + boolean equalsRange(LiteralByteString other, int offset, int length) { + if (length > other.size()) { + throw new IllegalArgumentException( + "Length too large: " + length + size()); + } + if (offset + length > other.size()) { + throw new IllegalArgumentException( + "Ran off end of other: " + offset + ", " + length + ", " + + other.size()); + } + + byte[] thisBytes = bytes; + byte[] otherBytes = other.bytes; + int thisLimit = getOffsetIntoBytes() + length; + for (int thisIndex = getOffsetIntoBytes(), otherIndex = + other.getOffsetIntoBytes() + offset; + (thisIndex < thisLimit); ++thisIndex, ++otherIndex) { + if (thisBytes[thisIndex] != otherBytes[otherIndex]) { + return false; + } + } + return true; + } + + /** + * Cached hash value. Intentionally accessed via a data race, which + * is safe because of the Java Memory Model's "no out-of-thin-air values" + * guarantees for ints. + */ + private int hash = 0; + + /** + * Compute the hashCode using the traditional algorithm from {@link + * ByteString}. + * + * @return hashCode value + */ + @Override + public int hashCode() { + int h = hash; + + if (h == 0) { + int size = size(); + h = partialHash(size, 0, size); + if (h == 0) { + h = 1; + } + hash = h; + } + return h; + } + + @Override + protected int peekCachedHashCode() { + return hash; + } + + @Override + protected int partialHash(int h, int offset, int length) { + return hashCode(h, bytes, getOffsetIntoBytes() + offset, length); + } + + static int hashCode(int h, byte[] bytes, int offset, int length) { + for (int i = offset; i < offset + length; i++) { + h = h * 31 + bytes[i]; + } + return h; + } + + static int hashCode(byte[] bytes) { + int h = hashCode(bytes.length, bytes, 0, bytes.length); + return h == 0 ? 1 : h; + } + + // ================================================================= + // Input stream + + @Override + public InputStream newInput() { + return new ByteArrayInputStream(bytes, getOffsetIntoBytes(), + size()); // No copy + } + + @Override + public CodedInputStream newCodedInput() { + // We trust CodedInputStream not to modify the bytes, or to give anyone + // else access to them. + return CodedInputStream.newInstance(this); + } + + // ================================================================= + // ByteIterator + + @Override + public ByteIterator iterator() { + return new LiteralByteIterator(); + } + + private class LiteralByteIterator implements ByteIterator { + private int position; + private final int limit; + + private LiteralByteIterator() { + position = 0; + limit = size(); + } + + public boolean hasNext() { + return (position < limit); + } + + public Byte next() { + // Boxing calls Byte.valueOf(byte), which does not instantiate. + return nextByte(); + } + + public byte nextByte() { + try { + return bytes[position++]; + } catch (ArrayIndexOutOfBoundsException e) { + throw new NoSuchElementException(e.getMessage()); + } + } + + public void remove() { + throw new UnsupportedOperationException(); + } + } + + // ================================================================= + // Internal methods + + @Override + protected int getTreeDepth() { + return 0; + } + + @Override + protected boolean isBalanced() { + return true; + } + + /** + * Offset into {@code bytes[]} to use, non-zero for substrings. + * + * @return always 0 for this class + */ + protected int getOffsetIntoBytes() { + return 0; + } +} |