| /* |
| * Copyright 2016-present Open Networking Foundation |
| * |
| * 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 com.google.common.base.Preconditions.checkNotNull; |
| import static java.lang.String.format; |
| 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 { |
| |
| private enum BitwiseOp { |
| AND, |
| OR, |
| XOR |
| } |
| |
| /* |
| 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 all bits are 0. |
| * |
| * @param size number of bytes |
| * @return a new immutable byte sequence |
| */ |
| public static ImmutableByteSequence ofZeros(int size) { |
| // array is initialized to all 0's by default |
| return new ImmutableByteSequence(ByteBuffer.wrap(new byte[size])); |
| } |
| |
| /** |
| * Creates a new byte sequence of the given size where all 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)); |
| } |
| |
| /** |
| * Creates a new byte sequence that is prefixed with specified number of |
| * zeros if val = 0 or ones if val = 0xff. |
| * |
| * @param size number of total bytes |
| * @param prefixBits number of bits in prefix |
| * @param val 0 for prefix of zeros; 0xff for prefix of ones |
| * @return new immutable byte sequence |
| */ |
| static ImmutableByteSequence prefix(int size, long prefixBits, byte val) { |
| checkArgument(val == 0 || val == (byte) 0xff, "Val must be 0 or 0xff"); |
| byte[] bytes = new byte[size]; |
| int prefixBytes = (int) (prefixBits / Byte.SIZE); |
| Arrays.fill(bytes, 0, prefixBytes, val); |
| Arrays.fill(bytes, prefixBytes, bytes.length, (byte) ~val); |
| int partialBits = (int) (prefixBits % Byte.SIZE); |
| if (partialBits != 0) { |
| bytes[prefixBytes] = val == 0 ? |
| (byte) (0xff >> partialBits) : (byte) (0xff << Byte.SIZE - partialBits); |
| } |
| return new ImmutableByteSequence(ByteBuffer.wrap(bytes)); |
| } |
| |
| /** |
| * Creates a new byte sequence that is prefixed with specified number of |
| * zeros. |
| * |
| * @param size number of total bytes |
| * @param prefixBits number of bits in prefix |
| * @return new immutable byte sequence |
| */ |
| public static ImmutableByteSequence prefixZeros(int size, long prefixBits) { |
| return prefix(size, prefixBits, (byte) 0); |
| } |
| |
| /** |
| * Creates a new byte sequence that is prefixed with specified number of |
| * ones. |
| * |
| * @param size number of total bytes |
| * @param prefixBits number of bits in prefix |
| * @return new immutable byte sequence |
| */ |
| public static ImmutableByteSequence prefixOnes(int size, long prefixBits) { |
| return prefix(size, prefixBits, (byte) 0xff); |
| } |
| |
| /** |
| * 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; |
| } |
| |
| private ImmutableByteSequence doBitwiseOp(ImmutableByteSequence other, BitwiseOp op) { |
| checkArgument(other != null && this.size() == other.size(), |
| "Other sequence must be non null and with same size as this"); |
| byte[] newBytes = new byte[this.size()]; |
| byte[] thisBytes = this.asArray(); |
| byte[] otherBytes = other.asArray(); |
| for (int i = 0; i < this.size(); i++) { |
| switch (op) { |
| case AND: |
| newBytes[i] = (byte) (thisBytes[i] & otherBytes[i]); |
| break; |
| case OR: |
| newBytes[i] = (byte) (thisBytes[i] | otherBytes[i]); |
| break; |
| case XOR: |
| newBytes[i] = (byte) (thisBytes[i] ^ otherBytes[i]); |
| break; |
| default: |
| throw new IllegalArgumentException( |
| "Unknown bitwise operator " + op.name()); |
| } |
| } |
| return ImmutableByteSequence.copyFrom(newBytes); |
| } |
| |
| /** |
| * Returns a new byte sequence corresponding to the result of a bitwise AND |
| * operation between this sequence and the given other, i.e. {@code this & |
| * other}. |
| * |
| * @param other other byte sequence |
| * @return new byte sequence |
| * @throws IllegalArgumentException if other sequence is null or its size is |
| * different than this sequence size |
| */ |
| public ImmutableByteSequence bitwiseAnd(ImmutableByteSequence other) { |
| return doBitwiseOp(other, BitwiseOp.AND); |
| } |
| |
| /** |
| * Returns a new byte sequence corresponding to the result of a bitwise OR |
| * operation between this sequence and the given other, i.e. {@code this | |
| * other}. |
| * |
| * @param other other byte sequence |
| * @return new byte sequence |
| * @throws IllegalArgumentException if other sequence is null or its size is |
| * different than this sequence size |
| */ |
| public ImmutableByteSequence bitwiseOr(ImmutableByteSequence other) { |
| return doBitwiseOp(other, BitwiseOp.OR); |
| } |
| |
| /** |
| * Returns a new byte sequence corresponding to the result of a bitwise XOR |
| * operation between this sequence and the given other, i.e. {@code this ^ |
| * other}. |
| * |
| * @param other other byte sequence |
| * @return new byte sequence |
| * @throws IllegalArgumentException if other sequence is null or its size is |
| * different than this sequence size |
| */ |
| public ImmutableByteSequence bitwiseXor(ImmutableByteSequence other) { |
| return doBitwiseOp(other, BitwiseOp.XOR); |
| } |
| |
| @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); |
| } |
| |
| /** |
| * Returns the index of the most significant bit (MSB), assuming a bit |
| * numbering scheme of type "LSB 0", i.e. the bit numbering starts at zero |
| * for the least significant bit (LSB). The MSB index of a byte sequence of |
| * zeros will be -1. |
| * <p> |
| * As an example, the following conditions always hold true: {@code |
| * ImmutableByteSequence.copyFrom(0).msbIndex() == -1 |
| * ImmutableByteSequence.copyFrom(1).msbIndex() == 0 |
| * ImmutableByteSequence.copyFrom(2).msbIndex() == 1 |
| * ImmutableByteSequence.copyFrom(3).msbIndex() == 1 |
| * ImmutableByteSequence.copyFrom(4).msbIndex() == 2 |
| * ImmutableByteSequence.copyFrom(512).msbIndex() == 9 } |
| * |
| * @return index of the MSB, -1 if the sequence has all bytes set to 0 |
| */ |
| public int msbIndex() { |
| int index = (size() * 8) - 1; |
| byteLoop: |
| for (int i = 0; i < size(); i++) { |
| byte b = value.get(i); |
| if (b != 0) { |
| for (int j = 7; j >= 0; j--) { |
| byte mask = (byte) ((1 << j) - 1); |
| if ((b & ~mask) != 0) { |
| break byteLoop; |
| } |
| index--; |
| } |
| } |
| index -= 8; |
| } |
| return index; |
| } |
| |
| @Override |
| public String toString() { |
| return HexString.toHexString(value.array()); |
| } |
| |
| /** |
| * Trims or expands a copy of this byte sequence so to fit the given |
| * bit-width. When trimming, the operations is deemed to be safe only if the |
| * trimmed bits are zero, i.e. it is safe to trim only when {@code bitWidth |
| * > msbIndex()}, otherwise an exception will be thrown. When expanding, the |
| * sequence will be padded with zeros. The returned byte sequence will have |
| * minimum size to contain the given bit-width. |
| * |
| * @param bitWidth a non-zero positive integer |
| * @return a new byte sequence |
| * @throws ByteSequenceTrimException if the byte sequence cannot be fitted |
| */ |
| public ImmutableByteSequence fit(int bitWidth) throws ByteSequenceTrimException { |
| return doFit(this, bitWidth); |
| } |
| |
| /** |
| * Trims or expands the given byte sequence so to fit a given bit-width. |
| * When trimming, the operations is deemed to be safe only if the trimmed |
| * bits are zero, i.e. it is safe to trim only when {@code bitWidth > |
| * msbIndex()}, otherwise an exception will be thrown. When expanding, the |
| * sequence will be padded with zeros. The returned byte sequence will have |
| * minimum size to contain the given bit-width. |
| * |
| * @param original a byte sequence |
| * @param bitWidth a non-zero positive integer |
| * @return a new byte sequence |
| * @throws ByteSequenceTrimException if the byte sequence cannot be fitted |
| * @deprecated in ONOS 1.13, use {@link ImmutableByteSequence#fit(int)} |
| * instead. |
| */ |
| @Deprecated |
| public static ImmutableByteSequence fit(ImmutableByteSequence original, |
| int bitWidth) |
| throws ByteSequenceTrimException { |
| return doFit(original, bitWidth); |
| } |
| |
| private static ImmutableByteSequence doFit(ImmutableByteSequence original, |
| int bitWidth) |
| throws ByteSequenceTrimException { |
| |
| checkNotNull(original, "byte sequence cannot be null"); |
| checkArgument(bitWidth > 0, "bit-width must be a non-zero positive integer"); |
| |
| int newByteWidth = (int) Math.ceil((double) bitWidth / 8); |
| |
| if (bitWidth == original.size() * 8) { |
| // No need to fit. |
| return original; |
| } |
| |
| ByteBuffer newBuffer = ByteBuffer.allocate(newByteWidth); |
| |
| if (newByteWidth > original.size()) { |
| // Pad extra bytes with 0's. |
| int numPadBytes = newByteWidth - original.size(); |
| for (int i = 0; i < numPadBytes; i++) { |
| newBuffer.put((byte) 0x00); |
| } |
| newBuffer.put(original.asReadOnlyBuffer()); |
| } else { |
| // Trim sequence. |
| if (bitWidth > original.msbIndex()) { |
| int diff = original.size() - newByteWidth; |
| ByteBuffer originalBuffer = original.asReadOnlyBuffer(); |
| for (int i = diff; i < original.size(); i++) { |
| newBuffer.put(originalBuffer.get(i)); |
| } |
| } else { |
| throw new ByteSequenceTrimException(original, bitWidth); |
| } |
| } |
| |
| return new ImmutableByteSequence(newBuffer); |
| } |
| |
| /** |
| * Signals that a byte sequence cannot be trimmed. |
| */ |
| public static class ByteSequenceTrimException extends Exception { |
| ByteSequenceTrimException(ImmutableByteSequence original, int bitWidth) { |
| super(format("cannot trim %s into a %d bits long value", |
| original, bitWidth)); |
| } |
| } |
| } |