| /* |
| * Copyright 2016-present Open Networking Laboratory |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.onlab.util; |
| |
| import com.google.common.base.Objects; |
| |
| import java.nio.ByteBuffer; |
| import java.nio.ByteOrder; |
| import java.util.Arrays; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static org.apache.commons.lang3.ArrayUtils.reverse; |
| |
| /** |
| * Immutable sequence of bytes, assumed to represent a value in |
| * {@link ByteOrder#BIG_ENDIAN BIG_ENDIAN} order. |
| * <p> |
| * Sequences can be created copying from an already existing representation of a |
| * sequence of bytes, such as {@link ByteBuffer} or {@code byte[]}; or by |
| * copying bytes from a primitive data type, such as {@code long}, {@code int} |
| * or {@code short}. In the first case, bytes are assumed to be already given in |
| * big-endian order, while in the second case big-endianness is enforced by this |
| * class. |
| */ |
| public final class ImmutableByteSequence { |
| |
| /* |
| Actual bytes are backed by a byte buffer. |
| The order of a newly-created byte buffer is always BIG_ENDIAN. |
| */ |
| private ByteBuffer value; |
| |
| /** |
| * Private constructor. |
| * Creates a new byte sequence object backed by the passed ByteBuffer. |
| * |
| * @param value a byte buffer |
| */ |
| private ImmutableByteSequence(ByteBuffer value) { |
| this.value = value; |
| // Rewind buffer so it's ready to be read. |
| // No write operation should be performed on it from now on. |
| this.value.rewind(); |
| } |
| |
| /** |
| * Creates a new immutable byte sequence with the same content and order of |
| * the passed byte array. |
| * |
| * @param original a byte array value |
| * @return a new immutable byte sequence |
| */ |
| public static ImmutableByteSequence copyFrom(byte[] original) { |
| checkArgument(original != null && original.length > 0, |
| "Cannot copy from an empty or null array"); |
| return new ImmutableByteSequence( |
| ByteBuffer.allocate(original.length).put(original)); |
| } |
| |
| /** |
| * Creates a new immutable byte sequence with the same content and order of |
| * the passed byte array, from/to the given indexes (inclusive). |
| * |
| * @param original a byte array value |
| * @param fromIdx starting index |
| * @param toIdx ending index |
| * @return a new immutable byte sequence |
| */ |
| public static ImmutableByteSequence copyFrom(byte[] original, int fromIdx, int toIdx) { |
| checkArgument(original != null && original.length > 0, |
| "Cannot copy from an empty or null array"); |
| checkArgument(toIdx >= fromIdx && toIdx < original.length, "invalid indexes"); |
| ByteBuffer buffer = ByteBuffer.allocate((toIdx - fromIdx) + 1); |
| for (int i = fromIdx; i <= toIdx; i++) { |
| buffer.put(original[i]); |
| } |
| return new ImmutableByteSequence(buffer); |
| } |
| |
| /** |
| * Creates a new immutable byte sequence copying bytes from the given |
| * ByteBuffer {@link ByteBuffer}. If the byte buffer order is not big-endian |
| * bytes will be copied in reverse order. |
| * |
| * @param original a byte buffer |
| * @return a new byte buffer object |
| */ |
| public static ImmutableByteSequence copyFrom(ByteBuffer original) { |
| checkArgument(original != null && original.capacity() > 0, |
| "Cannot copy from an empty or null byte buffer"); |
| |
| byte[] bytes = new byte[original.capacity()]; |
| |
| // copy bytes from original buffer |
| original.rewind(); |
| original.get(bytes); |
| |
| if (original.order() == ByteOrder.LITTLE_ENDIAN) { |
| // FIXME: this can be improved, e.g. read bytes in reverse order from original |
| reverse(bytes); |
| } |
| |
| return new ImmutableByteSequence(ByteBuffer.wrap(bytes)); |
| } |
| |
| /** |
| * Creates a new byte sequence of 8 bytes containing the given long value. |
| * |
| * @param original a long value |
| * @return a new immutable byte sequence |
| */ |
| public static ImmutableByteSequence copyFrom(long original) { |
| return new ImmutableByteSequence( |
| ByteBuffer.allocate(Long.BYTES).putLong(original)); |
| } |
| |
| /** |
| * Creates a new byte sequence of 4 bytes containing the given int value. |
| * |
| * @param original an int value |
| * @return a new immutable byte sequence |
| */ |
| public static ImmutableByteSequence copyFrom(int original) { |
| return new ImmutableByteSequence( |
| ByteBuffer.allocate(Integer.BYTES).putInt(original)); |
| } |
| |
| /** |
| * Creates a new byte sequence of 2 bytes containing the given short value. |
| * |
| * @param original a short value |
| * @return a new immutable byte sequence |
| */ |
| public static ImmutableByteSequence copyFrom(short original) { |
| return new ImmutableByteSequence( |
| ByteBuffer.allocate(Short.BYTES).putShort(original)); |
| } |
| |
| /** |
| * Creates a new byte sequence of 1 byte containing the given value. |
| * |
| * @param original a byte value |
| * @return a new immutable byte sequence |
| */ |
| public static ImmutableByteSequence copyFrom(byte original) { |
| return new ImmutableByteSequence( |
| ByteBuffer.allocate(Byte.BYTES).put(original)); |
| } |
| |
| /** |
| * Creates a new byte sequence of the given size where alla bits are 0. |
| * |
| * @param size number of bytes |
| * @return a new immutable byte sequence |
| */ |
| public static ImmutableByteSequence ofZeros(int size) { |
| byte[] bytes = new byte[size]; |
| Arrays.fill(bytes, (byte) 0); |
| return new ImmutableByteSequence(ByteBuffer.wrap(bytes)); |
| } |
| |
| /** |
| * Creates a new byte sequence of the given size where alla bits are 1. |
| * |
| * @param size number of bytes |
| * @return a new immutable byte sequence |
| */ |
| public static ImmutableByteSequence ofOnes(int size) { |
| byte[] bytes = new byte[size]; |
| Arrays.fill(bytes, (byte) 0xFF); |
| return new ImmutableByteSequence(ByteBuffer.wrap(bytes)); |
| } |
| |
| /** |
| * Returns a view of this sequence as a read-only {@link ByteBuffer}. |
| * <p> |
| * The returned buffer will have position 0, while limit and capacity will |
| * be set to this sequence {@link #size()}. The buffer order will be |
| * big-endian. |
| * |
| * @return a read-only byte buffer |
| */ |
| public ByteBuffer asReadOnlyBuffer() { |
| // position, limit and capacity set rewind at constructor |
| return value.asReadOnlyBuffer(); |
| } |
| |
| /** |
| * Gets the number of bytes in this sequence. |
| * |
| * @return an integer value |
| */ |
| public int size() { |
| return this.value.capacity(); |
| } |
| |
| /** |
| * Creates a new byte array view of this sequence. |
| * |
| * @return a new byte array |
| */ |
| public byte[] asArray() { |
| ByteBuffer bb = asReadOnlyBuffer(); |
| byte[] bytes = new byte[size()]; |
| bb.get(bytes); |
| return bytes; |
| } |
| |
| @Override |
| public int hashCode() { |
| return value.hashCode(); |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) { |
| return true; |
| } |
| if (obj == null || getClass() != obj.getClass()) { |
| return false; |
| } |
| final ImmutableByteSequence other = (ImmutableByteSequence) obj; |
| return Objects.equal(this.value, other.value); |
| } |
| |
| @Override |
| public String toString() { |
| return HexString.toHexString(value.array()); |
| } |
| } |