Carmelo Cascone | 6b32c99 | 2016-04-13 11:53:09 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2016-present Open Networking Laboratory |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package org.onlab.util; |
| 18 | |
| 19 | import com.google.common.base.MoreObjects; |
| 20 | import com.google.common.base.Objects; |
| 21 | |
| 22 | import java.nio.ByteBuffer; |
| 23 | import java.nio.ByteOrder; |
Carmelo Cascone | aa8b629 | 2016-04-13 14:27:06 -0700 | [diff] [blame] | 24 | import java.util.Arrays; |
Carmelo Cascone | 6b32c99 | 2016-04-13 11:53:09 -0700 | [diff] [blame] | 25 | |
| 26 | import static com.google.common.base.Preconditions.checkArgument; |
| 27 | import static org.apache.commons.lang3.ArrayUtils.reverse; |
| 28 | |
| 29 | /** |
| 30 | * Immutable sequence of bytes, assumed to represent a value in |
| 31 | * {@link ByteOrder#BIG_ENDIAN BIG_ENDIAN} order. |
| 32 | * <p> |
| 33 | * Sequences can be created copying from an already existing representation of a |
| 34 | * sequence of bytes, such as {@link ByteBuffer} or {@code byte[]}; or by |
| 35 | * copying bytes from a primitive data type, such as {@code long}, {@code int} |
| 36 | * or {@code short}. In the first case, bytes are assumed to be already given in |
| 37 | * big-endian order, while in the second case big-endianness is enforced by this |
| 38 | * class. |
| 39 | */ |
| 40 | public final class ImmutableByteSequence { |
| 41 | |
| 42 | /* |
| 43 | Actual bytes are backed by a byte buffer. |
| 44 | The order of a newly-created byte buffer is always BIG_ENDIAN. |
| 45 | */ |
| 46 | private ByteBuffer value; |
| 47 | |
| 48 | /** |
| 49 | * Private constructor. |
| 50 | * Creates a new byte sequence object backed by the passed ByteBuffer. |
| 51 | * |
| 52 | * @param value a byte buffer |
| 53 | */ |
| 54 | private ImmutableByteSequence(ByteBuffer value) { |
| 55 | this.value = value; |
| 56 | // Rewind buffer so it's ready to be read. |
| 57 | // No write operation should be performed on it from now on. |
| 58 | this.value.rewind(); |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * Creates a new immutable byte sequence with the same content and order of |
| 63 | * the passed byte array. |
| 64 | * |
| 65 | * @param original a byte array value |
Carmelo Cascone | aa8b629 | 2016-04-13 14:27:06 -0700 | [diff] [blame] | 66 | * @return a new immutable byte sequence |
Carmelo Cascone | 6b32c99 | 2016-04-13 11:53:09 -0700 | [diff] [blame] | 67 | */ |
| 68 | public static ImmutableByteSequence copyFrom(byte[] original) { |
| 69 | checkArgument(original != null && original.length > 0, |
| 70 | "Cannot copy from an empty or null array"); |
| 71 | return new ImmutableByteSequence( |
| 72 | ByteBuffer.allocate(original.length).put(original)); |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Creates a new immutable byte sequence copying bytes from the given |
| 77 | * ByteBuffer {@link ByteBuffer}. If the byte buffer order is not big-endian |
| 78 | * bytes will be copied in reverse order. |
| 79 | * |
| 80 | * @param original a byte buffer |
| 81 | * @return a new byte buffer object |
| 82 | */ |
| 83 | public static ImmutableByteSequence copyFrom(ByteBuffer original) { |
| 84 | checkArgument(original != null && original.capacity() > 0, |
| 85 | "Cannot copy from an empty or null byte buffer"); |
| 86 | |
| 87 | byte[] bytes = new byte[original.capacity()]; |
| 88 | |
| 89 | // copy bytes from original buffer |
| 90 | original.rewind(); |
| 91 | original.get(bytes); |
| 92 | |
| 93 | if (original.order() == ByteOrder.LITTLE_ENDIAN) { |
| 94 | // FIXME: this can be improved, e.g. read bytes in reverse order from original |
| 95 | reverse(bytes); |
| 96 | } |
| 97 | |
| 98 | return new ImmutableByteSequence(ByteBuffer.wrap(bytes)); |
| 99 | } |
| 100 | |
| 101 | /** |
| 102 | * Creates a new byte sequence of 8 bytes containing the given long value. |
| 103 | * |
| 104 | * @param original a long value |
Carmelo Cascone | aa8b629 | 2016-04-13 14:27:06 -0700 | [diff] [blame] | 105 | * @return a new immutable byte sequence |
Carmelo Cascone | 6b32c99 | 2016-04-13 11:53:09 -0700 | [diff] [blame] | 106 | */ |
| 107 | public static ImmutableByteSequence copyFrom(long original) { |
| 108 | return new ImmutableByteSequence( |
| 109 | ByteBuffer.allocate(Long.BYTES).putLong(original)); |
| 110 | } |
| 111 | |
| 112 | /** |
| 113 | * Creates a new byte sequence of 4 bytes containing the given int value. |
| 114 | * |
| 115 | * @param original an int value |
Carmelo Cascone | aa8b629 | 2016-04-13 14:27:06 -0700 | [diff] [blame] | 116 | * @return a new immutable byte sequence |
Carmelo Cascone | 6b32c99 | 2016-04-13 11:53:09 -0700 | [diff] [blame] | 117 | */ |
| 118 | public static ImmutableByteSequence copyFrom(int original) { |
| 119 | return new ImmutableByteSequence( |
| 120 | ByteBuffer.allocate(Integer.BYTES).putInt(original)); |
| 121 | } |
| 122 | |
| 123 | /** |
| 124 | * Creates a new byte sequence of 2 bytes containing the given short value. |
| 125 | * |
| 126 | * @param original a short value |
Carmelo Cascone | aa8b629 | 2016-04-13 14:27:06 -0700 | [diff] [blame] | 127 | * @return a new immutable byte sequence |
Carmelo Cascone | 6b32c99 | 2016-04-13 11:53:09 -0700 | [diff] [blame] | 128 | */ |
| 129 | public static ImmutableByteSequence copyFrom(short original) { |
| 130 | return new ImmutableByteSequence( |
| 131 | ByteBuffer.allocate(Short.BYTES).putShort(original)); |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * Creates a new byte sequence of 1 byte containing the given value. |
| 136 | * |
| 137 | * @param original a byte value |
Carmelo Cascone | aa8b629 | 2016-04-13 14:27:06 -0700 | [diff] [blame] | 138 | * @return a new immutable byte sequence |
Carmelo Cascone | 6b32c99 | 2016-04-13 11:53:09 -0700 | [diff] [blame] | 139 | */ |
| 140 | public static ImmutableByteSequence copyFrom(byte original) { |
| 141 | return new ImmutableByteSequence( |
| 142 | ByteBuffer.allocate(Byte.BYTES).put(original)); |
| 143 | } |
| 144 | |
| 145 | /** |
Carmelo Cascone | aa8b629 | 2016-04-13 14:27:06 -0700 | [diff] [blame] | 146 | * Creates a new byte sequence of the given size where alla bits are 0. |
| 147 | * |
| 148 | * @param size number of bytes |
| 149 | * @return a new immutable byte sequence |
| 150 | */ |
| 151 | public static ImmutableByteSequence ofZeros(int size) { |
| 152 | byte[] bytes = new byte[size]; |
| 153 | Arrays.fill(bytes, (byte) 0); |
| 154 | return new ImmutableByteSequence(ByteBuffer.wrap(bytes)); |
| 155 | } |
| 156 | |
| 157 | /** |
| 158 | * Creates a new byte sequence of the given size where alla bits are 1. |
| 159 | * |
| 160 | * @param size number of bytes |
| 161 | * @return a new immutable byte sequence |
| 162 | */ |
| 163 | public static ImmutableByteSequence ofOnes(int size) { |
| 164 | byte[] bytes = new byte[size]; |
| 165 | Arrays.fill(bytes, (byte) 0xFF); |
| 166 | return new ImmutableByteSequence(ByteBuffer.wrap(bytes)); |
| 167 | } |
| 168 | |
| 169 | /** |
Carmelo Cascone | 6b32c99 | 2016-04-13 11:53:09 -0700 | [diff] [blame] | 170 | * Returns a view of this sequence as a read-only {@link ByteBuffer}. |
| 171 | * <p> |
| 172 | * The returned buffer will have position 0, while limit and capacity will |
| 173 | * be set to this sequence {@link #size()}. The buffer order will be |
| 174 | * big-endian. |
| 175 | * |
| 176 | * @return a read-only byte buffer |
| 177 | */ |
| 178 | public ByteBuffer asReadOnlyBuffer() { |
| 179 | // position, limit and capacity set rewind at constructor |
| 180 | return value.asReadOnlyBuffer(); |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * Gets the number of bytes in this sequence. |
| 185 | * |
| 186 | * @return an integer value |
| 187 | */ |
| 188 | public int size() { |
| 189 | return this.value.capacity(); |
| 190 | } |
| 191 | |
| 192 | /** |
| 193 | * Creates a new byte array view of this sequence. |
| 194 | * |
| 195 | * @return a new byte array |
| 196 | */ |
| 197 | public byte[] asArray() { |
| 198 | ByteBuffer bb = asReadOnlyBuffer(); |
| 199 | byte[] bytes = new byte[size()]; |
| 200 | bb.get(bytes); |
| 201 | return bytes; |
| 202 | } |
| 203 | |
| 204 | @Override |
| 205 | public int hashCode() { |
| 206 | return value.hashCode(); |
| 207 | } |
| 208 | |
| 209 | @Override |
| 210 | public boolean equals(Object obj) { |
| 211 | if (this == obj) { |
| 212 | return true; |
| 213 | } |
| 214 | if (obj == null || getClass() != obj.getClass()) { |
| 215 | return false; |
| 216 | } |
| 217 | final ImmutableByteSequence other = (ImmutableByteSequence) obj; |
| 218 | return Objects.equal(this.value, other.value); |
| 219 | } |
| 220 | |
| 221 | @Override |
| 222 | public String toString() { |
| 223 | return MoreObjects.toStringHelper(this) |
| 224 | .addValue(HexString.toHexString(asArray())) |
| 225 | .toString(); |
| 226 | } |
| 227 | } |