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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.hadoop.hbase.util;

import static org.apache.hbase.thirdparty.com.google.common.base.Preconditions.checkArgument;
import static org.apache.hbase.thirdparty.com.google.common.base.Preconditions.checkNotNull;
import static org.apache.hbase.thirdparty.com.google.common.base.Preconditions.checkPositionIndex;

import com.google.protobuf.ByteString;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellComparator;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.unsafe.HBasePlatformDependent;
import org.apache.hadoop.io.RawComparator;
import org.apache.hadoop.io.WritableComparator;
import org.apache.hadoop.io.WritableUtils;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hbase.thirdparty.org.apache.commons.collections4.CollectionUtils;

/**
 * Utility class that handles byte arrays, conversions to/from other types, comparisons, hash code
 * generation, manufacturing keys for HashMaps or HashSets, and can be used as key in maps or trees.
 */
@InterfaceAudience.Public
@edu.umd.cs.findbugs.annotations.SuppressWarnings(
    value = "EQ_CHECK_FOR_OPERAND_NOT_COMPATIBLE_WITH_THIS",
    justification = "It has been like this forever")
public class Bytes implements Comparable {

  // Using the charset canonical name for String/byte[] conversions is much
  // more efficient due to use of cached encoders/decoders.
  private static final String UTF8_CSN = StandardCharsets.UTF_8.name();

  // HConstants.EMPTY_BYTE_ARRAY should be updated if this changed
  private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];

  private static final Logger LOG = LoggerFactory.getLogger(Bytes.class);

  /**
   * Size of boolean in bytes
   */
  public static final int SIZEOF_BOOLEAN = Byte.SIZE / Byte.SIZE;

  /**
   * Size of byte in bytes
   */
  public static final int SIZEOF_BYTE = SIZEOF_BOOLEAN;

  /**
   * Size of char in bytes
   */
  public static final int SIZEOF_CHAR = Character.SIZE / Byte.SIZE;

  /**
   * Size of double in bytes
   */
  public static final int SIZEOF_DOUBLE = Double.SIZE / Byte.SIZE;

  /**
   * Size of float in bytes
   */
  public static final int SIZEOF_FLOAT = Float.SIZE / Byte.SIZE;

  /**
   * Size of int in bytes
   */
  public static final int SIZEOF_INT = Integer.SIZE / Byte.SIZE;

  /**
   * Size of long in bytes
   */
  public static final int SIZEOF_LONG = Long.SIZE / Byte.SIZE;

  /**
   * Size of short in bytes
   */
  public static final int SIZEOF_SHORT = Short.SIZE / Byte.SIZE;

  /**
   * Mask to apply to a long to reveal the lower int only. Use like this: int i =
   * (int)(0xFFFFFFFF00000000L ^ some_long_value);
   */
  public static final long MASK_FOR_LOWER_INT_IN_LONG = 0xFFFFFFFF00000000L;

  /**
   * Estimate of size cost to pay beyond payload in jvm for instance of byte []. Estimate based on
   * study of jhat and jprofiler numbers.
   */
  // JHat says BU is 56 bytes.
  // SizeOf which uses java.lang.instrument says 24 bytes. (3 longs?)
  public static final int ESTIMATED_HEAP_TAX = 16;

  @InterfaceAudience.Private
  static final boolean UNSAFE_UNALIGNED = HBasePlatformDependent.unaligned();

  /**
   * Returns length of the byte array, returning 0 if the array is null. Useful for calculating
   * sizes.
   * @param b byte array, which can be null
   * @return 0 if b is null, otherwise returns length
   */
  final public static int len(byte[] b) {
    return b == null ? 0 : b.length;
  }

  private byte[] bytes;
  private int offset;
  private int length;

  /**
   * Create a zero-size sequence.
   */
  public Bytes() {
    super();
  }

  /**
   * Create a Bytes using the byte array as the initial value.
   * @param bytes This array becomes the backing storage for the object.
   */
  public Bytes(byte[] bytes) {
    this(bytes, 0, bytes.length);
  }

  /**
   * Set the new Bytes to the contents of the passed ibw.
   * @param ibw the value to set this Bytes to.
   */
  public Bytes(final Bytes ibw) {
    this(ibw.get(), ibw.getOffset(), ibw.getLength());
  }

  /**
   * Set the value to a given byte range
   * @param bytes  the new byte range to set to
   * @param offset the offset in newData to start at
   * @param length the number of bytes in the range
   */
  public Bytes(final byte[] bytes, final int offset, final int length) {
    this.bytes = bytes;
    this.offset = offset;
    this.length = length;
  }

  /**
   * Copy bytes from ByteString instance.
   * @param byteString copy from
   * @deprecated As of release 2.0.0, this will be removed in HBase 3.0.0.
   */
  @Deprecated
  public Bytes(final ByteString byteString) {
    this(byteString.toByteArray());
  }

  /**
   * Get the data from the Bytes.
   * @return The data is only valid between offset and offset+length.
   */
  public byte[] get() {
    if (this.bytes == null) {
      throw new IllegalStateException(
        "Uninitialiized. Null constructor " + "called w/o accompaying readFields invocation");
    }
    return this.bytes;
  }

  /**
   * @param b Use passed bytes as backing array for this instance.
   */
  public void set(final byte[] b) {
    set(b, 0, b.length);
  }

  /**
   * @param b Use passed bytes as backing array for this instance. nn
   */
  public void set(final byte[] b, final int offset, final int length) {
    this.bytes = b;
    this.offset = offset;
    this.length = length;
  }

  /**
   * @return the number of valid bytes in the buffer
   * @deprecated since 2.0.0 and will be removed in 3.0.0. Use {@link #getLength()} instead.
   * @see #getLength()
   * @see HBASE-11862
   */
  @Deprecated
  public int getSize() {
    if (this.bytes == null) {
      throw new IllegalStateException(
        "Uninitialiized. Null constructor " + "called w/o accompaying readFields invocation");
    }
    return this.length;
  }

  /** Returns the number of valid bytes in the buffer */
  public int getLength() {
    if (this.bytes == null) {
      throw new IllegalStateException(
        "Uninitialiized. Null constructor " + "called w/o accompaying readFields invocation");
    }
    return this.length;
  }

  /**
   * n
   */
  public int getOffset() {
    return this.offset;
  }

  /**
   * @deprecated As of release 2.0.0, this will be removed in HBase 3.0.0.
   */
  @Deprecated
  public ByteString toByteString() {
    return ByteString.copyFrom(this.bytes, this.offset, this.length);
  }

  @Override
  public int hashCode() {
    return Bytes.hashCode(bytes, offset, length);
  }

  /**
   * Define the sort order of the Bytes.
   * @param that The other bytes writable
   * @return Positive if left is bigger than right, 0 if they are equal, and negative if left is
   *         smaller than right.
   */
  @Override
  public int compareTo(Bytes that) {
    return BYTES_RAWCOMPARATOR.compare(this.bytes, this.offset, this.length, that.bytes,
      that.offset, that.length);
  }

  /**
   * Compares the bytes in this object to the specified byte array n * @return Positive if left is
   * bigger than right, 0 if they are equal, and negative if left is smaller than right.
   */
  public int compareTo(final byte[] that) {
    return BYTES_RAWCOMPARATOR.compare(this.bytes, this.offset, this.length, that, 0, that.length);
  }

  /**
   * @see Object#equals(Object)
   */
  @Override
  public boolean equals(Object right_obj) {
    if (right_obj instanceof byte[]) {
      return compareTo((byte[]) right_obj) == 0;
    }
    if (right_obj instanceof Bytes) {
      return compareTo((Bytes) right_obj) == 0;
    }
    return false;
  }

  /**
   * @see Object#toString()
   */
  @Override
  public String toString() {
    return Bytes.toString(bytes, offset, length);
  }

  /**
   * @param array List of byte [].
   * @return Array of byte [].
   */
  public static byte[][] toArray(final List array) {
    // List#toArray doesn't work on lists of byte [].
    byte[][] results = new byte[array.size()][];
    for (int i = 0; i < array.size(); i++) {
      results[i] = array.get(i);
    }
    return results;
  }

  /**
   * Returns a copy of the bytes referred to by this writable
   */
  public byte[] copyBytes() {
    return Arrays.copyOfRange(bytes, offset, offset + length);
  }

  /**
   * Byte array comparator class.
   */
  @InterfaceAudience.Public
  public static class ByteArrayComparator implements RawComparator {
    /**
     * Constructor
     */
    public ByteArrayComparator() {
      super();
    }

    @Override
    public int compare(byte[] left, byte[] right) {
      return compareTo(left, right);
    }

    @Override
    public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
      return LexicographicalComparerHolder.BEST_COMPARER.compareTo(b1, s1, l1, b2, s2, l2);
    }
  }

  /**
   * A {@link ByteArrayComparator} that treats the empty array as the largest value. This is useful
   * for comparing row end keys for regions.
   */
  // TODO: unfortunately, HBase uses byte[0] as both start and end keys for region
  // boundaries. Thus semantically, we should treat empty byte array as the smallest value
  // while comparing row keys, start keys etc; but as the largest value for comparing
  // region boundaries for endKeys.
  @InterfaceAudience.Public
  public static class RowEndKeyComparator extends ByteArrayComparator {
    @Override
    public int compare(byte[] left, byte[] right) {
      return compare(left, 0, left.length, right, 0, right.length);
    }

    @Override
    public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
      if (b1 == b2 && s1 == s2 && l1 == l2) {
        return 0;
      }
      if (l1 == 0) {
        return l2; // 0 or positive
      }
      if (l2 == 0) {
        return -1;
      }
      return super.compare(b1, s1, l1, b2, s2, l2);
    }
  }

  /**
   * Pass this to TreeMaps where byte [] are keys.
   */
  public final static Comparator BYTES_COMPARATOR = new ByteArrayComparator();

  /**
   * Use comparing byte arrays, byte-by-byte
   */
  public final static RawComparator BYTES_RAWCOMPARATOR = new ByteArrayComparator();

  /**
   * Read byte-array written with a WritableableUtils.vint prefix.
   * @param in Input to read from.
   * @return byte array read off in
   * @throws IOException e
   */
  public static byte[] readByteArray(final DataInput in) throws IOException {
    int len = WritableUtils.readVInt(in);
    if (len < 0) {
      throw new NegativeArraySizeException(Integer.toString(len));
    }
    byte[] result = new byte[len];
    in.readFully(result, 0, len);
    return result;
  }

  /**
   * Read byte-array written with a WritableableUtils.vint prefix. IOException is converted to a
   * RuntimeException.
   * @param in Input to read from.
   * @return byte array read off in
   */
  public static byte[] readByteArrayThrowsRuntime(final DataInput in) {
    try {
      return readByteArray(in);
    } catch (Exception e) {
      throw new RuntimeException(e);
    }
  }

  /**
   * Write byte-array with a WritableableUtils.vint prefix.
   * @param out output stream to be written to
   * @param b   array to write
   * @throws IOException e
   */
  public static void writeByteArray(final DataOutput out, final byte[] b) throws IOException {
    if (b == null) {
      WritableUtils.writeVInt(out, 0);
    } else {
      writeByteArray(out, b, 0, b.length);
    }
  }

  /**
   * Write byte-array to out with a vint length prefix.
   * @param out    output stream
   * @param b      array
   * @param offset offset into array
   * @param length length past offset
   * @throws IOException e
   */
  public static void writeByteArray(final DataOutput out, final byte[] b, final int offset,
    final int length) throws IOException {
    WritableUtils.writeVInt(out, length);
    out.write(b, offset, length);
  }

  /**
   * Write byte-array from src to tgt with a vint length prefix.
   * @param tgt       target array
   * @param tgtOffset offset into target array
   * @param src       source array
   * @param srcOffset source offset
   * @param srcLength source length
   * @return New offset in src array.
   */
  public static int writeByteArray(final byte[] tgt, final int tgtOffset, final byte[] src,
    final int srcOffset, final int srcLength) {
    byte[] vint = vintToBytes(srcLength);
    System.arraycopy(vint, 0, tgt, tgtOffset, vint.length);
    int offset = tgtOffset + vint.length;
    System.arraycopy(src, srcOffset, tgt, offset, srcLength);
    return offset + srcLength;
  }

  /**
   * Put bytes at the specified byte array position.
   * @param tgtBytes  the byte array
   * @param tgtOffset position in the array
   * @param srcBytes  array to write out
   * @param srcOffset source offset
   * @param srcLength source length
   * @return incremented offset
   */
  public static int putBytes(byte[] tgtBytes, int tgtOffset, byte[] srcBytes, int srcOffset,
    int srcLength) {
    System.arraycopy(srcBytes, srcOffset, tgtBytes, tgtOffset, srcLength);
    return tgtOffset + srcLength;
  }

  /**
   * Write a single byte out to the specified byte array position.
   * @param bytes  the byte array
   * @param offset position in the array
   * @param b      byte to write out
   * @return incremented offset
   */
  public static int putByte(byte[] bytes, int offset, byte b) {
    bytes[offset] = b;
    return offset + 1;
  }

  /**
   * Add the whole content of the ByteBuffer to the bytes arrays. The ByteBuffer is modified.
   * @param bytes  the byte array
   * @param offset position in the array
   * @param buf    ByteBuffer to write out
   * @return incremented offset
   */
  public static int putByteBuffer(byte[] bytes, int offset, ByteBuffer buf) {
    int len = buf.remaining();
    buf.get(bytes, offset, len);
    return offset + len;
  }

  /**
   * Returns a new byte array, copied from the given {@code buf}, from the index 0 (inclusive) to
   * the limit (exclusive), regardless of the current position. The position and the other index
   * parameters are not changed.
   * @param buf a byte buffer
   * @return the byte array
   * @see #getBytes(ByteBuffer)
   */
  public static byte[] toBytes(ByteBuffer buf) {
    ByteBuffer dup = buf.duplicate();
    dup.position(0);
    return readBytes(dup);
  }

  private static byte[] readBytes(ByteBuffer buf) {
    byte[] result = new byte[buf.remaining()];
    buf.get(result);
    return result;
  }

  /**
   * @param b Presumed UTF-8 encoded byte array.
   * @return String made from b
   */
  public static String toString(final byte[] b) {
    if (b == null) {
      return null;
    }
    return toString(b, 0, b.length);
  }

  /**
   * Joins two byte arrays together using a separator.
   * @param b1  The first byte array.
   * @param sep The separator to use.
   * @param b2  The second byte array.
   */
  public static String toString(final byte[] b1, String sep, final byte[] b2) {
    return toString(b1, 0, b1.length) + sep + toString(b2, 0, b2.length);
  }

  /**
   * This method will convert utf8 encoded bytes into a string. If the given byte array is null,
   * this method will return null.
   * @param b   Presumed UTF-8 encoded byte array.
   * @param off offset into array
   * @return String made from b or null
   */
  public static String toString(final byte[] b, int off) {
    if (b == null) {
      return null;
    }
    int len = b.length - off;
    if (len <= 0) {
      return "";
    }
    try {
      return new String(b, off, len, UTF8_CSN);
    } catch (UnsupportedEncodingException e) {
      // should never happen!
      throw new IllegalArgumentException("UTF8 encoding is not supported", e);
    }
  }

  /**
   * This method will convert utf8 encoded bytes into a string. If the given byte array is null,
   * this method will return null.
   * @param b   Presumed UTF-8 encoded byte array.
   * @param off offset into array
   * @param len length of utf-8 sequence
   * @return String made from b or null
   */
  public static String toString(final byte[] b, int off, int len) {
    if (b == null) {
      return null;
    }
    if (len == 0) {
      return "";
    }
    try {
      return new String(b, off, len, UTF8_CSN);
    } catch (UnsupportedEncodingException e) {
      // should never happen!
      throw new IllegalArgumentException("UTF8 encoding is not supported", e);
    }
  }

  /**
   * Write a printable representation of a byte array.
   * @param b byte array n * @see #toStringBinary(byte[], int, int)
   */
  public static String toStringBinary(final byte[] b) {
    if (b == null) return "null";
    return toStringBinary(b, 0, b.length);
  }

  /**
   * Converts the given byte buffer to a printable representation, from the index 0 (inclusive) to
   * the limit (exclusive), regardless of the current position. The position and the other index
   * parameters are not changed.
   * @param buf a byte buffer
   * @return a string representation of the buffer's binary contents
   * @see #toBytes(ByteBuffer)
   * @see #getBytes(ByteBuffer)
   */
  public static String toStringBinary(ByteBuffer buf) {
    if (buf == null) return "null";
    if (buf.hasArray()) {
      return toStringBinary(buf.array(), buf.arrayOffset(), buf.limit());
    }
    return toStringBinary(toBytes(buf));
  }

  private static final char[] HEX_CHARS_UPPER =
    { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

  /**
   * Write a printable representation of a byte array. Non-printable characters are hex escaped in
   * the format \\x%02X, eg: \x00 \x05 etc
   * @param b   array to write out
   * @param off offset to start at
   * @param len length to write
   * @return string output
   */
  public static String toStringBinary(final byte[] b, int off, int len) {
    StringBuilder result = new StringBuilder();
    // Just in case we are passed a 'len' that is > buffer length...
    if (off >= b.length) return result.toString();
    if (off + len > b.length) len = b.length - off;
    for (int i = off; i < off + len; ++i) {
      int ch = b[i] & 0xFF;
      if (ch >= ' ' && ch <= '~' && ch != '\\') {
        result.append((char) ch);
      } else {
        result.append("\\x");
        result.append(HEX_CHARS_UPPER[ch / 0x10]);
        result.append(HEX_CHARS_UPPER[ch % 0x10]);
      }
    }
    return result.toString();
  }

  private static boolean isHexDigit(char c) {
    return (c >= 'A' && c <= 'F') || (c >= '0' && c <= '9');
  }

  /**
   * Takes a ASCII digit in the range A-F0-9 and returns the corresponding integer/ordinal value.
   * @param ch The hex digit.
   * @return The converted hex value as a byte.
   */
  public static byte toBinaryFromHex(byte ch) {
    if (ch >= 'A' && ch <= 'F') return (byte) ((byte) 10 + (byte) (ch - 'A'));
    // else
    return (byte) (ch - '0');
  }

  public static byte[] toBytesBinary(String in) {
    // this may be bigger than we need, but let's be safe.
    byte[] b = new byte[in.length()];
    int size = 0;
    for (int i = 0; i < in.length(); ++i) {
      char ch = in.charAt(i);
      if (ch == '\\' && in.length() > i + 1 && in.charAt(i + 1) == 'x') {
        // ok, take next 2 hex digits.
        char hd1 = in.charAt(i + 2);
        char hd2 = in.charAt(i + 3);

        // they need to be A-F0-9:
        if (!isHexDigit(hd1) || !isHexDigit(hd2)) {
          // bogus escape code, ignore:
          continue;
        }
        // turn hex ASCII digit -> number
        byte d = (byte) ((toBinaryFromHex((byte) hd1) << 4) + toBinaryFromHex((byte) hd2));

        b[size++] = d;
        i += 3; // skip 3
      } else {
        b[size++] = (byte) ch;
      }
    }
    // resize:
    byte[] b2 = new byte[size];
    System.arraycopy(b, 0, b2, 0, size);
    return b2;
  }

  /**
   * Converts a string to a UTF-8 byte array.
   * @param s string
   * @return the byte array
   */
  public static byte[] toBytes(String s) {
    try {
      return s.getBytes(UTF8_CSN);
    } catch (UnsupportedEncodingException e) {
      // should never happen!
      throw new IllegalArgumentException("UTF8 decoding is not supported", e);
    }
  }

  /**
   * Convert a boolean to a byte array. True becomes -1 and false becomes 0.
   * @param b value
   * @return b encoded in a byte array.
   */
  public static byte[] toBytes(final boolean b) {
    return new byte[] { b ? (byte) -1 : (byte) 0 };
  }

  /**
   * Reverses {@link #toBytes(boolean)}
   * @param b array
   * @return True or false.
   */
  public static boolean toBoolean(final byte[] b) {
    if (b.length != 1) {
      throw new IllegalArgumentException("Array has wrong size: " + b.length);
    }
    return b[0] != (byte) 0;
  }

  /**
   * Convert a long value to a byte array using big-endian.
   * @param val value to convert
   * @return the byte array
   */
  public static byte[] toBytes(long val) {
    byte[] b = new byte[8];
    for (int i = 7; i > 0; i--) {
      b[i] = (byte) val;
      val >>>= 8;
    }
    b[0] = (byte) val;
    return b;
  }

  /**
   * Converts a byte array to a long value. Reverses {@link #toBytes(long)}
   * @param bytes array
   * @return the long value
   */
  public static long toLong(byte[] bytes) {
    return toLong(bytes, 0, SIZEOF_LONG);
  }

  /**
   * Converts a byte array to a long value. Assumes there will be {@link #SIZEOF_LONG} bytes
   * available.
   * @param bytes  bytes
   * @param offset offset
   * @return the long value
   */
  public static long toLong(byte[] bytes, int offset) {
    return toLong(bytes, offset, SIZEOF_LONG);
  }

  /**
   * Converts a byte array to a long value.
   * @param bytes  array of bytes
   * @param offset offset into array
   * @param length length of data (must be {@link #SIZEOF_LONG})
   * @return the long value
   * @throws IllegalArgumentException if length is not {@link #SIZEOF_LONG} or if there's not enough
   *                                  room in the array at the offset indicated.
   */
  public static long toLong(byte[] bytes, int offset, final int length) {
    if (length != SIZEOF_LONG || offset + length > bytes.length) {
      throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_LONG);
    }
    return ConverterHolder.BEST_CONVERTER.toLong(bytes, offset, length);
  }

  private static IllegalArgumentException explainWrongLengthOrOffset(final byte[] bytes,
    final int offset, final int length, final int expectedLength) {
    String reason;
    if (length != expectedLength) {
      reason = "Wrong length: " + length + ", expected " + expectedLength;
    } else {
      reason = "offset (" + offset + ") + length (" + length + ") exceed the"
        + " capacity of the array: " + bytes.length;
    }
    return new IllegalArgumentException(reason);
  }

  /**
   * Put a long value out to the specified byte array position.
   * @param bytes  the byte array
   * @param offset position in the array
   * @param val    long to write out
   * @return incremented offset
   * @throws IllegalArgumentException if the byte array given doesn't have enough room at the offset
   *                                  specified.
   */
  public static int putLong(byte[] bytes, int offset, long val) {
    if (bytes.length - offset < SIZEOF_LONG) {
      throw new IllegalArgumentException("Not enough room to put a long at" + " offset " + offset
        + " in a " + bytes.length + " byte array");
    }
    return ConverterHolder.BEST_CONVERTER.putLong(bytes, offset, val);
  }

  /**
   * Put a long value out to the specified byte array position (Unsafe).
   * @param bytes  the byte array
   * @param offset position in the array
   * @param val    long to write out
   * @return incremented offset
   * @deprecated As of release 2.0.0, this will be removed in HBase 3.0.0.
   */
  @Deprecated
  public static int putLongUnsafe(byte[] bytes, int offset, long val) {
    return UnsafeAccess.putLong(bytes, offset, val);
  }

  /**
   * Presumes float encoded as IEEE 754 floating-point "single format"
   * @param bytes byte array
   * @return Float made from passed byte array.
   */
  public static float toFloat(byte[] bytes) {
    return toFloat(bytes, 0);
  }

  /**
   * Presumes float encoded as IEEE 754 floating-point "single format"
   * @param bytes  array to convert
   * @param offset offset into array
   * @return Float made from passed byte array.
   */
  public static float toFloat(byte[] bytes, int offset) {
    return Float.intBitsToFloat(toInt(bytes, offset, SIZEOF_INT));
  }

  /**
   * @param bytes  byte array
   * @param offset offset to write to
   * @param f      float value
   * @return New offset in bytes
   */
  public static int putFloat(byte[] bytes, int offset, float f) {
    return putInt(bytes, offset, Float.floatToRawIntBits(f));
  }

  /**
   * @param f float value
   * @return the float represented as byte []
   */
  public static byte[] toBytes(final float f) {
    // Encode it as int
    return Bytes.toBytes(Float.floatToRawIntBits(f));
  }

  /**
   * @param bytes byte array
   * @return Return double made from passed bytes.
   */
  public static double toDouble(final byte[] bytes) {
    return toDouble(bytes, 0);
  }

  /**
   * @param bytes  byte array
   * @param offset offset where double is
   * @return Return double made from passed bytes.
   */
  public static double toDouble(final byte[] bytes, final int offset) {
    return Double.longBitsToDouble(toLong(bytes, offset, SIZEOF_LONG));
  }

  /**
   * @param bytes  byte array
   * @param offset offset to write to
   * @param d      value
   * @return New offset into array bytes
   */
  public static int putDouble(byte[] bytes, int offset, double d) {
    return putLong(bytes, offset, Double.doubleToLongBits(d));
  }

  /**
   * Serialize a double as the IEEE 754 double format output. The resultant array will be 8 bytes
   * long.
   * @param d value
   * @return the double represented as byte []
   */
  public static byte[] toBytes(final double d) {
    // Encode it as a long
    return Bytes.toBytes(Double.doubleToRawLongBits(d));
  }

  /**
   * Convert an int value to a byte array. Big-endian. Same as what DataOutputStream.writeInt does.
   * @param val value
   * @return the byte array
   */
  public static byte[] toBytes(int val) {
    byte[] b = new byte[4];
    for (int i = 3; i > 0; i--) {
      b[i] = (byte) val;
      val >>>= 8;
    }
    b[0] = (byte) val;
    return b;
  }

  /**
   * Converts a byte array to an int value
   * @param bytes byte array
   * @return the int value
   */
  public static int toInt(byte[] bytes) {
    return toInt(bytes, 0, SIZEOF_INT);
  }

  /**
   * Converts a byte array to an int value
   * @param bytes  byte array
   * @param offset offset into array
   * @return the int value
   */
  public static int toInt(byte[] bytes, int offset) {
    return toInt(bytes, offset, SIZEOF_INT);
  }

  /**
   * Converts a byte array to an int value
   * @param bytes  byte array
   * @param offset offset into array
   * @param length length of int (has to be {@link #SIZEOF_INT})
   * @return the int value
   * @throws IllegalArgumentException if length is not {@link #SIZEOF_INT} or if there's not enough
   *                                  room in the array at the offset indicated.
   */
  public static int toInt(byte[] bytes, int offset, final int length) {
    if (length != SIZEOF_INT || offset + length > bytes.length) {
      throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_INT);
    }
    return ConverterHolder.BEST_CONVERTER.toInt(bytes, offset, length);
  }

  /**
   * Converts a byte array to an int value (Unsafe version)
   * @param bytes  byte array
   * @param offset offset into array
   * @return the int value
   * @deprecated As of release 2.0.0, this will be removed in HBase 3.0.0.
   */
  @Deprecated
  public static int toIntUnsafe(byte[] bytes, int offset) {
    return UnsafeAccess.toInt(bytes, offset);
  }

  /**
   * Converts a byte array to an short value (Unsafe version)
   * @param bytes  byte array
   * @param offset offset into array
   * @return the short value
   * @deprecated As of release 2.0.0, this will be removed in HBase 3.0.0.
   */
  @Deprecated
  public static short toShortUnsafe(byte[] bytes, int offset) {
    return UnsafeAccess.toShort(bytes, offset);
  }

  /**
   * Converts a byte array to an long value (Unsafe version)
   * @param bytes  byte array
   * @param offset offset into array
   * @return the long value
   * @deprecated As of release 2.0.0, this will be removed in HBase 3.0.0.
   */
  @Deprecated
  public static long toLongUnsafe(byte[] bytes, int offset) {
    return UnsafeAccess.toLong(bytes, offset);
  }

  /**
   * Converts a byte array to an int value
   * @param bytes  byte array
   * @param offset offset into array
   * @param length how many bytes should be considered for creating int
   * @return the int value
   * @throws IllegalArgumentException if there's not enough room in the array at the offset
   *                                  indicated.
   */
  public static int readAsInt(byte[] bytes, int offset, final int length) {
    if (offset + length > bytes.length) {
      throw new IllegalArgumentException("offset (" + offset + ") + length (" + length
        + ") exceed the" + " capacity of the array: " + bytes.length);
    }
    int n = 0;
    for (int i = offset; i < (offset + length); i++) {
      n <<= 8;
      n ^= bytes[i] & 0xFF;
    }
    return n;
  }

  /**
   * Put an int value out to the specified byte array position.
   * @param bytes  the byte array
   * @param offset position in the array
   * @param val    int to write out
   * @return incremented offset
   * @throws IllegalArgumentException if the byte array given doesn't have enough room at the offset
   *                                  specified.
   */
  public static int putInt(byte[] bytes, int offset, int val) {
    if (bytes.length - offset < SIZEOF_INT) {
      throw new IllegalArgumentException("Not enough room to put an int at" + " offset " + offset
        + " in a " + bytes.length + " byte array");
    }
    return ConverterHolder.BEST_CONVERTER.putInt(bytes, offset, val);
  }

  /**
   * Put an int value out to the specified byte array position (Unsafe).
   * @param bytes  the byte array
   * @param offset position in the array
   * @param val    int to write out
   * @return incremented offset
   * @deprecated As of release 2.0.0, this will be removed in HBase 3.0.0.
   */
  @Deprecated
  public static int putIntUnsafe(byte[] bytes, int offset, int val) {
    return UnsafeAccess.putInt(bytes, offset, val);
  }

  /**
   * Convert a short value to a byte array of {@link #SIZEOF_SHORT} bytes long.
   * @param val value
   * @return the byte array
   */
  public static byte[] toBytes(short val) {
    byte[] b = new byte[SIZEOF_SHORT];
    b[1] = (byte) val;
    val >>= 8;
    b[0] = (byte) val;
    return b;
  }

  /**
   * Converts a byte array to a short value
   * @param bytes byte array
   * @return the short value
   */
  public static short toShort(byte[] bytes) {
    return toShort(bytes, 0, SIZEOF_SHORT);
  }

  /**
   * Converts a byte array to a short value
   * @param bytes  byte array
   * @param offset offset into array
   * @return the short value
   */
  public static short toShort(byte[] bytes, int offset) {
    return toShort(bytes, offset, SIZEOF_SHORT);
  }

  /**
   * Converts a byte array to a short value
   * @param bytes  byte array
   * @param offset offset into array
   * @param length length, has to be {@link #SIZEOF_SHORT}
   * @return the short value
   * @throws IllegalArgumentException if length is not {@link #SIZEOF_SHORT} or if there's not
   *                                  enough room in the array at the offset indicated.
   */
  public static short toShort(byte[] bytes, int offset, final int length) {
    if (length != SIZEOF_SHORT || offset + length > bytes.length) {
      throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_SHORT);
    }
    return ConverterHolder.BEST_CONVERTER.toShort(bytes, offset, length);
  }

  /**
   * Returns a new byte array, copied from the given {@code buf}, from the position (inclusive) to
   * the limit (exclusive). The position and the other index parameters are not changed.
   * @param buf a byte buffer
   * @return the byte array
   * @see #toBytes(ByteBuffer)
   */
  public static byte[] getBytes(ByteBuffer buf) {
    return readBytes(buf.duplicate());
  }

  /**
   * Put a short value out to the specified byte array position.
   * @param bytes  the byte array
   * @param offset position in the array
   * @param val    short to write out
   * @return incremented offset
   * @throws IllegalArgumentException if the byte array given doesn't have enough room at the offset
   *                                  specified.
   */
  public static int putShort(byte[] bytes, int offset, short val) {
    if (bytes.length - offset < SIZEOF_SHORT) {
      throw new IllegalArgumentException("Not enough room to put a short at" + " offset " + offset
        + " in a " + bytes.length + " byte array");
    }
    return ConverterHolder.BEST_CONVERTER.putShort(bytes, offset, val);
  }

  /**
   * Put a short value out to the specified byte array position (Unsafe).
   * @param bytes  the byte array
   * @param offset position in the array
   * @param val    short to write out
   * @return incremented offset
   * @deprecated As of release 2.0.0, this will be removed in HBase 3.0.0.
   */
  @Deprecated
  public static int putShortUnsafe(byte[] bytes, int offset, short val) {
    return UnsafeAccess.putShort(bytes, offset, val);
  }

  /**
   * Put an int value as short out to the specified byte array position. Only the lower 2 bytes of
   * the short will be put into the array. The caller of the API need to make sure they will not
   * loose the value by doing so. This is useful to store an unsigned short which is represented as
   * int in other parts.
   * @param bytes  the byte array
   * @param offset position in the array
   * @param val    value to write out
   * @return incremented offset
   * @throws IllegalArgumentException if the byte array given doesn't have enough room at the offset
   *                                  specified.
   */
  public static int putAsShort(byte[] bytes, int offset, int val) {
    if (bytes.length - offset < SIZEOF_SHORT) {
      throw new IllegalArgumentException("Not enough room to put a short at" + " offset " + offset
        + " in a " + bytes.length + " byte array");
    }
    bytes[offset + 1] = (byte) val;
    val >>= 8;
    bytes[offset] = (byte) val;
    return offset + SIZEOF_SHORT;
  }

  /**
   * Convert a BigDecimal value to a byte array n * @return the byte array
   */
  public static byte[] toBytes(BigDecimal val) {
    byte[] valueBytes = val.unscaledValue().toByteArray();
    byte[] result = new byte[valueBytes.length + SIZEOF_INT];
    int offset = putInt(result, 0, val.scale());
    putBytes(result, offset, valueBytes, 0, valueBytes.length);
    return result;
  }

  /**
   * Converts a byte array to a BigDecimal n * @return the char value
   */
  public static BigDecimal toBigDecimal(byte[] bytes) {
    return toBigDecimal(bytes, 0, bytes.length);
  }

  /**
   * Converts a byte array to a BigDecimal value nnn * @return the char value
   */
  public static BigDecimal toBigDecimal(byte[] bytes, int offset, final int length) {
    if (bytes == null || length < SIZEOF_INT + 1 || (offset + length > bytes.length)) {
      return null;
    }

    int scale = toInt(bytes, offset);
    byte[] tcBytes = new byte[length - SIZEOF_INT];
    System.arraycopy(bytes, offset + SIZEOF_INT, tcBytes, 0, length - SIZEOF_INT);
    return new BigDecimal(new BigInteger(tcBytes), scale);
  }

  /**
   * Put a BigDecimal value out to the specified byte array position.
   * @param bytes  the byte array
   * @param offset position in the array
   * @param val    BigDecimal to write out
   * @return incremented offset
   */
  public static int putBigDecimal(byte[] bytes, int offset, BigDecimal val) {
    if (bytes == null) {
      return offset;
    }

    byte[] valueBytes = val.unscaledValue().toByteArray();
    byte[] result = new byte[valueBytes.length + SIZEOF_INT];
    offset = putInt(result, offset, val.scale());
    return putBytes(result, offset, valueBytes, 0, valueBytes.length);
  }

  /**
   * @param vint Integer to make a vint of.
   * @return Vint as bytes array.
   */
  public static byte[] vintToBytes(final long vint) {
    long i = vint;
    int size = WritableUtils.getVIntSize(i);
    byte[] result = new byte[size];
    int offset = 0;
    if (i >= -112 && i <= 127) {
      result[offset] = (byte) i;
      return result;
    }

    int len = -112;
    if (i < 0) {
      i ^= -1L; // take one's complement'
      len = -120;
    }

    long tmp = i;
    while (tmp != 0) {
      tmp = tmp >> 8;
      len--;
    }

    result[offset++] = (byte) len;

    len = (len < -120) ? -(len + 120) : -(len + 112);

    for (int idx = len; idx != 0; idx--) {
      int shiftbits = (idx - 1) * 8;
      long mask = 0xFFL << shiftbits;
      result[offset++] = (byte) ((i & mask) >> shiftbits);
    }
    return result;
  }

  /**
   * @param buffer buffer to convert
   * @return vint bytes as an integer.
   */
  public static long bytesToVint(final byte[] buffer) {
    int offset = 0;
    byte firstByte = buffer[offset++];
    int len = WritableUtils.decodeVIntSize(firstByte);
    if (len == 1) {
      return firstByte;
    }
    long i = 0;
    for (int idx = 0; idx < len - 1; idx++) {
      byte b = buffer[offset++];
      i = i << 8;
      i = i | (b & 0xFF);
    }
    return (WritableUtils.isNegativeVInt(firstByte) ? ~i : i);
  }

  /**
   * Reads a zero-compressed encoded long from input buffer and returns it.
   * @param buffer Binary array
   * @param offset Offset into array at which vint begins.
   * @throws java.io.IOException e
   * @return deserialized long from buffer.
   * @deprecated since 0.98.12. Use {@link #readAsVLong(byte[],int)} instead.
   * @see #readAsVLong(byte[], int)
   * @see HBASE-6919
   */
  @Deprecated
  public static long readVLong(final byte[] buffer, final int offset) throws IOException {
    return readAsVLong(buffer, offset);
  }

  /**
   * Reads a zero-compressed encoded long from input buffer and returns it.
   * @param buffer Binary array
   * @param offset Offset into array at which vint begins.
   * @return deserialized long from buffer.
   */
  public static long readAsVLong(final byte[] buffer, final int offset) {
    byte firstByte = buffer[offset];
    int len = WritableUtils.decodeVIntSize(firstByte);
    if (len == 1) {
      return firstByte;
    }
    long i = 0;
    for (int idx = 0; idx < len - 1; idx++) {
      byte b = buffer[offset + 1 + idx];
      i = i << 8;
      i = i | (b & 0xFF);
    }
    return (WritableUtils.isNegativeVInt(firstByte) ? ~i : i);
  }

  /**
   * @param left  left operand
   * @param right right operand
   * @return 0 if equal, < 0 if left is less than right, etc.
   */
  public static int compareTo(final byte[] left, final byte[] right) {
    return LexicographicalComparerHolder.BEST_COMPARER.compareTo(left, 0,
      left == null ? 0 : left.length, right, 0, right == null ? 0 : right.length);
  }

  /**
   * Lexicographically compare two arrays.
   * @param buffer1 left operand
   * @param buffer2 right operand
   * @param offset1 Where to start comparing in the left buffer
   * @param offset2 Where to start comparing in the right buffer
   * @param length1 How much to compare from the left buffer
   * @param length2 How much to compare from the right buffer
   * @return 0 if equal, < 0 if left is less than right, etc.
   */
  public static int compareTo(byte[] buffer1, int offset1, int length1, byte[] buffer2, int offset2,
    int length2) {
    return LexicographicalComparerHolder.BEST_COMPARER.compareTo(buffer1, offset1, length1, buffer2,
      offset2, length2);
  }

  interface Comparer {
    int compareTo(T buffer1, int offset1, int length1, T buffer2, int offset2, int length2);
  }

  static abstract class Converter {
    abstract long toLong(byte[] bytes, int offset, int length);

    abstract int putLong(byte[] bytes, int offset, long val);

    abstract int toInt(byte[] bytes, int offset, final int length);

    abstract int putInt(byte[] bytes, int offset, int val);

    abstract short toShort(byte[] bytes, int offset, final int length);

    abstract int putShort(byte[] bytes, int offset, short val);

  }

  @InterfaceAudience.Private
  static Comparer lexicographicalComparerJavaImpl() {
    return LexicographicalComparerHolder.PureJavaComparer.INSTANCE;
  }

  static class ConverterHolder {
    static final String UNSAFE_CONVERTER_NAME =
      ConverterHolder.class.getName() + "$UnsafeConverter";

    static final Converter BEST_CONVERTER = getBestConverter();

    /**
     * Returns the Unsafe-using Converter, or falls back to the pure-Java implementation if unable
     * to do so.
     */
    static Converter getBestConverter() {
      try {
        Class theClass = Class.forName(UNSAFE_CONVERTER_NAME);

        // yes, UnsafeComparer does implement Comparer
        @SuppressWarnings("unchecked")
        Converter converter = (Converter) theClass.getConstructor().newInstance();
        return converter;
      } catch (Throwable t) { // ensure we really catch *everything*
        return PureJavaConverter.INSTANCE;
      }
    }

    protected static final class PureJavaConverter extends Converter {
      static final PureJavaConverter INSTANCE = new PureJavaConverter();

      private PureJavaConverter() {
      }

      @Override
      long toLong(byte[] bytes, int offset, int length) {
        long l = 0;
        for (int i = offset; i < offset + length; i++) {
          l <<= 8;
          l ^= bytes[i] & 0xFF;
        }
        return l;
      }

      @Override
      int putLong(byte[] bytes, int offset, long val) {
        for (int i = offset + 7; i > offset; i--) {
          bytes[i] = (byte) val;
          val >>>= 8;
        }
        bytes[offset] = (byte) val;
        return offset + SIZEOF_LONG;
      }

      @Override
      int toInt(byte[] bytes, int offset, int length) {
        int n = 0;
        for (int i = offset; i < (offset + length); i++) {
          n <<= 8;
          n ^= bytes[i] & 0xFF;
        }
        return n;
      }

      @Override
      int putInt(byte[] bytes, int offset, int val) {
        for (int i = offset + 3; i > offset; i--) {
          bytes[i] = (byte) val;
          val >>>= 8;
        }
        bytes[offset] = (byte) val;
        return offset + SIZEOF_INT;
      }

      @Override
      short toShort(byte[] bytes, int offset, int length) {
        short n = 0;
        n = (short) ((n ^ bytes[offset]) & 0xFF);
        n = (short) (n << 8);
        n ^= (short) (bytes[offset + 1] & 0xFF);
        return n;
      }

      @Override
      int putShort(byte[] bytes, int offset, short val) {
        bytes[offset + 1] = (byte) val;
        val >>= 8;
        bytes[offset] = (byte) val;
        return offset + SIZEOF_SHORT;
      }
    }

    protected static final class UnsafeConverter extends Converter {

      public UnsafeConverter() {
      }

      static {
        if (!UNSAFE_UNALIGNED) {
          // It doesn't matter what we throw;
          // it's swallowed in getBestComparer().
          throw new Error();
        }

        // sanity check - this should never fail
        if (HBasePlatformDependent.arrayIndexScale(byte[].class) != 1) {
          throw new AssertionError();
        }
      }

      @Override
      long toLong(byte[] bytes, int offset, int length) {
        return UnsafeAccess.toLong(bytes, offset);
      }

      @Override
      int putLong(byte[] bytes, int offset, long val) {
        return UnsafeAccess.putLong(bytes, offset, val);
      }

      @Override
      int toInt(byte[] bytes, int offset, int length) {
        return UnsafeAccess.toInt(bytes, offset);
      }

      @Override
      int putInt(byte[] bytes, int offset, int val) {
        return UnsafeAccess.putInt(bytes, offset, val);
      }

      @Override
      short toShort(byte[] bytes, int offset, int length) {
        return UnsafeAccess.toShort(bytes, offset);
      }

      @Override
      int putShort(byte[] bytes, int offset, short val) {
        return UnsafeAccess.putShort(bytes, offset, val);
      }
    }
  }

  /**
   * Provides a lexicographical comparer implementation; either a Java implementation or a faster
   * implementation based on {@code Unsafe}.
   * 

* Uses reflection to gracefully fall back to the Java implementation if {@code Unsafe} isn't * available. */ @InterfaceAudience.Private static class LexicographicalComparerHolder { static final String UNSAFE_COMPARER_NAME = LexicographicalComparerHolder.class.getName() + "$UnsafeComparer"; static final Comparer BEST_COMPARER = getBestComparer(); /** * Returns the Unsafe-using Comparer, or falls back to the pure-Java implementation if unable to * do so. */ static Comparer getBestComparer() { try { Class theClass = Class.forName(UNSAFE_COMPARER_NAME); // yes, UnsafeComparer does implement Comparer @SuppressWarnings("unchecked") Comparer comparer = (Comparer) theClass.getEnumConstants()[0]; return comparer; } catch (Throwable t) { // ensure we really catch *everything* return lexicographicalComparerJavaImpl(); } } enum PureJavaComparer implements Comparer { INSTANCE; @Override public int compareTo(byte[] buffer1, int offset1, int length1, byte[] buffer2, int offset2, int length2) { // Short circuit equal case if (buffer1 == buffer2 && offset1 == offset2 && length1 == length2) { return 0; } // Bring WritableComparator code local int end1 = offset1 + length1; int end2 = offset2 + length2; for (int i = offset1, j = offset2; i < end1 && j < end2; i++, j++) { int a = (buffer1[i] & 0xff); int b = (buffer2[j] & 0xff); if (a != b) { return a - b; } } return length1 - length2; } } @InterfaceAudience.Private enum UnsafeComparer implements Comparer { INSTANCE; static { if (!UNSAFE_UNALIGNED) { // It doesn't matter what we throw; // it's swallowed in getBestComparer(). throw new Error(); } // sanity check - this should never fail if (HBasePlatformDependent.arrayIndexScale(byte[].class) != 1) { throw new AssertionError(); } } /** * Lexicographically compare two arrays. * @param buffer1 left operand * @param buffer2 right operand * @param offset1 Where to start comparing in the left buffer * @param offset2 Where to start comparing in the right buffer * @param length1 How much to compare from the left buffer * @param length2 How much to compare from the right buffer * @return 0 if equal, < 0 if left is less than right, etc. */ @Override public int compareTo(byte[] buffer1, int offset1, int length1, byte[] buffer2, int offset2, int length2) { // Short circuit equal case if (buffer1 == buffer2 && offset1 == offset2 && length1 == length2) { return 0; } final int stride = 8; final int minLength = Math.min(length1, length2); int strideLimit = minLength & ~(stride - 1); final long offset1Adj = offset1 + UnsafeAccess.BYTE_ARRAY_BASE_OFFSET; final long offset2Adj = offset2 + UnsafeAccess.BYTE_ARRAY_BASE_OFFSET; int i; /* * Compare 8 bytes at a time. Benchmarking on x86 shows a stride of 8 bytes is no slower * than 4 bytes even on 32-bit. On the other hand, it is substantially faster on 64-bit. */ for (i = 0; i < strideLimit; i += stride) { long lw = HBasePlatformDependent.getLong(buffer1, offset1Adj + i); long rw = HBasePlatformDependent.getLong(buffer2, offset2Adj + i); if (lw != rw) { if (!UnsafeAccess.LITTLE_ENDIAN) { return ((lw + Long.MIN_VALUE) < (rw + Long.MIN_VALUE)) ? -1 : 1; } /* * We want to compare only the first index where left[index] != right[index]. This * corresponds to the least significant nonzero byte in lw ^ rw, since lw and rw are * little-endian. Long.numberOfTrailingZeros(diff) tells us the least significant * nonzero bit, and zeroing out the first three bits of L.nTZ gives us the shift to get * that least significant nonzero byte. This comparison logic is based on UnsignedBytes * comparator from guava v21 */ int n = Long.numberOfTrailingZeros(lw ^ rw) & ~0x7; return ((int) ((lw >>> n) & 0xFF)) - ((int) ((rw >>> n) & 0xFF)); } } // The epilogue to cover the last (minLength % stride) elements. for (; i < minLength; i++) { int a = (buffer1[offset1 + i] & 0xFF); int b = (buffer2[offset2 + i] & 0xFF); if (a != b) { return a - b; } } return length1 - length2; } } } /** * @param left left operand * @param right right operand * @return True if equal */ public static boolean equals(final byte[] left, final byte[] right) { // Could use Arrays.equals? // noinspection SimplifiableConditionalExpression if (left == right) return true; if (left == null || right == null) return false; if (left.length != right.length) return false; if (left.length == 0) return true; // Since we're often comparing adjacent sorted data, // it's usual to have equal arrays except for the very last byte // so check that first if (left[left.length - 1] != right[right.length - 1]) return false; return compareTo(left, right) == 0; } public static boolean equals(final byte[] left, int leftOffset, int leftLen, final byte[] right, int rightOffset, int rightLen) { // short circuit case if (left == right && leftOffset == rightOffset && leftLen == rightLen) { return true; } // different lengths fast check if (leftLen != rightLen) { return false; } if (leftLen == 0) { return true; } // Since we're often comparing adjacent sorted data, // it's usual to have equal arrays except for the very last byte // so check that first if (left[leftOffset + leftLen - 1] != right[rightOffset + rightLen - 1]) return false; return LexicographicalComparerHolder.BEST_COMPARER.compareTo(left, leftOffset, leftLen, right, rightOffset, rightLen) == 0; } /** * @param a left operand * @param buf right operand * @return True if equal */ public static boolean equals(byte[] a, ByteBuffer buf) { if (a == null) return buf == null; if (buf == null) return false; if (a.length != buf.remaining()) return false; // Thou shalt not modify the original byte buffer in what should be read only operations. ByteBuffer b = buf.duplicate(); for (byte anA : a) { if (anA != b.get()) { return false; } } return true; } /** * Return true if the byte array on the right is a prefix of the byte array on the left. */ public static boolean startsWith(byte[] bytes, byte[] prefix) { return bytes != null && prefix != null && bytes.length >= prefix.length && LexicographicalComparerHolder.BEST_COMPARER.compareTo(bytes, 0, prefix.length, prefix, 0, prefix.length) == 0; } /** * @param b bytes to hash * @return Runs {@link WritableComparator#hashBytes(byte[], int)} on the passed in array. This * method is what {@link org.apache.hadoop.io.Text} use calculating hash code. */ public static int hashCode(final byte[] b) { return hashCode(b, b.length); } /** * @param b value * @param length length of the value * @return Runs {@link WritableComparator#hashBytes(byte[], int)} on the passed in array. This * method is what {@link org.apache.hadoop.io.Text} use calculating hash code. */ public static int hashCode(final byte[] b, final int length) { return WritableComparator.hashBytes(b, length); } /** * @param b bytes to hash * @return A hash of b as an Integer that can be used as key in Maps. */ public static Integer mapKey(final byte[] b) { return hashCode(b); } /** * @param b bytes to hash * @param length length to hash * @return A hash of b as an Integer that can be used as key in Maps. */ public static Integer mapKey(final byte[] b, final int length) { return hashCode(b, length); } /** * @param a lower half * @param b upper half * @return New array that has a in lower half and b in upper half. */ public static byte[] add(final byte[] a, final byte[] b) { return add(a, b, EMPTY_BYTE_ARRAY); } /** * @param a first third * @param b second third * @param c third third * @return New array made from a, b and c */ public static byte[] add(final byte[] a, final byte[] b, final byte[] c) { byte[] result = new byte[a.length + b.length + c.length]; System.arraycopy(a, 0, result, 0, a.length); System.arraycopy(b, 0, result, a.length, b.length); System.arraycopy(c, 0, result, a.length + b.length, c.length); return result; } /** * @param arrays all the arrays to concatenate together. * @return New array made from the concatenation of the given arrays. */ public static byte[] add(final byte[][] arrays) { int length = 0; for (int i = 0; i < arrays.length; i++) { length += arrays[i].length; } byte[] result = new byte[length]; int index = 0; for (int i = 0; i < arrays.length; i++) { System.arraycopy(arrays[i], 0, result, index, arrays[i].length); index += arrays[i].length; } return result; } /** * @param a array * @param length amount of bytes to grab * @return First length bytes from a */ public static byte[] head(final byte[] a, final int length) { if (a.length < length) { return null; } byte[] result = new byte[length]; System.arraycopy(a, 0, result, 0, length); return result; } /** * @param a array * @param length amount of bytes to snarf * @return Last length bytes from a */ public static byte[] tail(final byte[] a, final int length) { if (a.length < length) { return null; } byte[] result = new byte[length]; System.arraycopy(a, a.length - length, result, 0, length); return result; } /** * @param a array * @param length new array size * @return Value in a plus length prepended 0 bytes */ public static byte[] padHead(final byte[] a, final int length) { byte[] padding = new byte[length]; for (int i = 0; i < length; i++) { padding[i] = 0; } return add(padding, a); } /** * @param a array * @param length new array size * @return Value in a plus length appended 0 bytes */ public static byte[] padTail(final byte[] a, final int length) { byte[] padding = new byte[length]; for (int i = 0; i < length; i++) { padding[i] = 0; } return add(a, padding); } /** * Split passed range. Expensive operation relatively. Uses BigInteger math. Useful splitting * ranges for MapReduce jobs. * @param a Beginning of range * @param b End of range * @param num Number of times to split range. Pass 1 if you want to split the range in two; i.e. * one split. * @return Array of dividing values */ public static byte[][] split(final byte[] a, final byte[] b, final int num) { return split(a, b, false, num); } /** * Split passed range. Expensive operation relatively. Uses BigInteger math. Useful splitting * ranges for MapReduce jobs. * @param a Beginning of range * @param b End of range * @param inclusive Whether the end of range is prefix-inclusive or is considered an exclusive * boundary. Automatic splits are generally exclusive and manual splits with an * explicit range utilize an inclusive end of range. * @param num Number of times to split range. Pass 1 if you want to split the range in two; * i.e. one split. * @return Array of dividing values */ public static byte[][] split(final byte[] a, final byte[] b, boolean inclusive, final int num) { byte[][] ret = new byte[num + 2][]; int i = 0; Iterable iter = iterateOnSplits(a, b, inclusive, num); if (iter == null) return null; for (byte[] elem : iter) { ret[i++] = elem; } return ret; } /** * Iterate over keys within the passed range, splitting at an [a,b) boundary. */ public static Iterable iterateOnSplits(final byte[] a, final byte[] b, final int num) { return iterateOnSplits(a, b, false, num); } /** * Iterate over keys within the passed range. */ public static Iterable iterateOnSplits(final byte[] a, final byte[] b, boolean inclusive, final int num) { byte[] aPadded; byte[] bPadded; if (a.length < b.length) { aPadded = padTail(a, b.length - a.length); bPadded = b; } else if (b.length < a.length) { aPadded = a; bPadded = padTail(b, a.length - b.length); } else { aPadded = a; bPadded = b; } if (compareTo(aPadded, bPadded) >= 0) { throw new IllegalArgumentException("b <= a"); } if (num <= 0) { throw new IllegalArgumentException("num cannot be <= 0"); } byte[] prependHeader = { 1, 0 }; final BigInteger startBI = new BigInteger(add(prependHeader, aPadded)); final BigInteger stopBI = new BigInteger(add(prependHeader, bPadded)); BigInteger diffBI = stopBI.subtract(startBI); if (inclusive) { diffBI = diffBI.add(BigInteger.ONE); } final BigInteger splitsBI = BigInteger.valueOf(num + 1); // when diffBI < splitBI, use an additional byte to increase diffBI if (diffBI.compareTo(splitsBI) < 0) { byte[] aPaddedAdditional = new byte[aPadded.length + 1]; byte[] bPaddedAdditional = new byte[bPadded.length + 1]; for (int i = 0; i < aPadded.length; i++) { aPaddedAdditional[i] = aPadded[i]; } for (int j = 0; j < bPadded.length; j++) { bPaddedAdditional[j] = bPadded[j]; } aPaddedAdditional[aPadded.length] = 0; bPaddedAdditional[bPadded.length] = 0; return iterateOnSplits(aPaddedAdditional, bPaddedAdditional, inclusive, num); } final BigInteger intervalBI; try { intervalBI = diffBI.divide(splitsBI); } catch (Exception e) { LOG.error("Exception caught during division", e); return null; } final Iterator iterator = new Iterator() { private int i = -1; @Override public boolean hasNext() { return i < num + 1; } @Override public byte[] next() { i++; if (i == 0) return a; if (i == num + 1) return b; BigInteger curBI = startBI.add(intervalBI.multiply(BigInteger.valueOf(i))); byte[] padded = curBI.toByteArray(); if (padded[1] == 0) padded = tail(padded, padded.length - 2); else padded = tail(padded, padded.length - 1); return padded; } @Override public void remove() { throw new UnsupportedOperationException(); } }; return new Iterable() { @Override public Iterator iterator() { return iterator; } }; } /** * @param bytes array to hash * @param offset offset to start from * @param length length to hash */ public static int hashCode(byte[] bytes, int offset, int length) { int hash = 1; for (int i = offset; i < offset + length; i++) hash = (31 * hash) + bytes[i]; return hash; } /** * @param t operands * @return Array of byte arrays made from passed array of Text */ public static byte[][] toByteArrays(final String[] t) { byte[][] result = new byte[t.length][]; for (int i = 0; i < t.length; i++) { result[i] = Bytes.toBytes(t[i]); } return result; } /** * @param t operands * @return Array of binary byte arrays made from passed array of binary strings */ public static byte[][] toBinaryByteArrays(final String[] t) { byte[][] result = new byte[t.length][]; for (int i = 0; i < t.length; i++) { result[i] = Bytes.toBytesBinary(t[i]); } return result; } /** * @param column operand * @return A byte array of a byte array where first and only entry is column */ public static byte[][] toByteArrays(final String column) { return toByteArrays(toBytes(column)); } /** * @param column operand * @return A byte array of a byte array where first and only entry is column */ public static byte[][] toByteArrays(final byte[] column) { byte[][] result = new byte[1][]; result[0] = column; return result; } /** * Binary search for keys in indexes. * @param arr array of byte arrays to search for * @param key the key you want to find * @param offset the offset in the key you want to find * @param length the length of the key * @param comparator a comparator to compare. * @return zero-based index of the key, if the key is present in the array. Otherwise, a value -(i * + 1) such that the key is between arr[i - 1] and arr[i] non-inclusively, where i is in * [0, i], if we define arr[-1] = -Inf and arr[N] = Inf for an N-element array. The above * means that this function can return 2N + 1 different values ranging from -(N + 1) to N * - 1. * @deprecated since 2.0.0 and will be removed in 3.0.0. Use * {@link #binarySearch(byte[][], byte[], int, int)} instead. * @see #binarySearch(byte[][], byte[], int, int) * @see HBASE-13450 */ @Deprecated public static int binarySearch(byte[][] arr, byte[] key, int offset, int length, RawComparator comparator) { return binarySearch(arr, key, offset, length); } /** * Binary search for keys in indexes using Bytes.BYTES_RAWCOMPARATOR. * @param arr array of byte arrays to search for * @param key the key you want to find * @param offset the offset in the key you want to find * @param length the length of the key * @return zero-based index of the key, if the key is present in the array. Otherwise, a value -(i * + 1) such that the key is between arr[i - 1] and arr[i] non-inclusively, where i is in * [0, i], if we define arr[-1] = -Inf and arr[N] = Inf for an N-element array. The above * means that this function can return 2N + 1 different values ranging from -(N + 1) to N * - 1. */ public static int binarySearch(byte[][] arr, byte[] key, int offset, int length) { int low = 0; int high = arr.length - 1; while (low <= high) { int mid = low + ((high - low) >> 1); // we have to compare in this order, because the comparator order // has special logic when the 'left side' is a special key. int cmp = Bytes.BYTES_RAWCOMPARATOR.compare(key, offset, length, arr[mid], 0, arr[mid].length); // key lives above the midpoint if (cmp > 0) low = mid + 1; // key lives below the midpoint else if (cmp < 0) high = mid - 1; // BAM. how often does this really happen? else return mid; } return -(low + 1); } /** * Binary search for keys in indexes. * @param arr array of byte arrays to search for * @param key the key you want to find * @param comparator a comparator to compare. * @return zero-based index of the key, if the key is present in the array. Otherwise, a value -(i * + 1) such that the key is between arr[i - 1] and arr[i] non-inclusively, where i is in * [0, i], if we define arr[-1] = -Inf and arr[N] = Inf for an N-element array. The above * means that this function can return 2N + 1 different values ranging from -(N + 1) to N * - 1. * @return the index of the block * @deprecated since 2.0.0 and will be removed in 3.0.0. Use * {@link #binarySearch(Cell[], Cell, CellComparator)} instead. * @see #binarySearch(Cell[], Cell, CellComparator) * @see HBASE-13450 */ @Deprecated public static int binarySearch(byte[][] arr, Cell key, RawComparator comparator) { int low = 0; int high = arr.length - 1; KeyValue.KeyOnlyKeyValue r = new KeyValue.KeyOnlyKeyValue(); while (low <= high) { int mid = low + ((high - low) >> 1); // we have to compare in this order, because the comparator order // has special logic when the 'left side' is a special key. r.setKey(arr[mid], 0, arr[mid].length); int cmp = comparator.compare(key, r); // key lives above the midpoint if (cmp > 0) low = mid + 1; // key lives below the midpoint else if (cmp < 0) high = mid - 1; // BAM. how often does this really happen? else return mid; } return -(low + 1); } /** * Binary search for keys in indexes. * @param arr array of byte arrays to search for * @param key the key you want to find * @param comparator a comparator to compare. * @return zero-based index of the key, if the key is present in the array. Otherwise, a value -(i * + 1) such that the key is between arr[i - 1] and arr[i] non-inclusively, where i is in * [0, i], if we define arr[-1] = -Inf and arr[N] = Inf for an N-element array. The above * means that this function can return 2N + 1 different values ranging from -(N + 1) to N * - 1. * @return the index of the block */ public static int binarySearch(Cell[] arr, Cell key, CellComparator comparator) { int low = 0; int high = arr.length - 1; while (low <= high) { int mid = low + ((high - low) >> 1); // we have to compare in this order, because the comparator order // has special logic when the 'left side' is a special key. int cmp = comparator.compare(key, arr[mid]); // key lives above the midpoint if (cmp > 0) low = mid + 1; // key lives below the midpoint else if (cmp < 0) high = mid - 1; // BAM. how often does this really happen? else return mid; } return -(low + 1); } /** * Bytewise binary increment/deincrement of long contained in byte array on given amount. * @param value - array of bytes containing long (length <= SIZEOF_LONG) * @param amount value will be incremented on (deincremented if negative) * @return array of bytes containing incremented long (length == SIZEOF_LONG) */ public static byte[] incrementBytes(byte[] value, long amount) { byte[] val = value; if (val.length < SIZEOF_LONG) { // Hopefully this doesn't happen too often. byte[] newvalue; if (val[0] < 0) { newvalue = new byte[] { -1, -1, -1, -1, -1, -1, -1, -1 }; } else { newvalue = new byte[SIZEOF_LONG]; } System.arraycopy(val, 0, newvalue, newvalue.length - val.length, val.length); val = newvalue; } else if (val.length > SIZEOF_LONG) { throw new IllegalArgumentException("Increment Bytes - value too big: " + val.length); } if (amount == 0) return val; if (val[0] < 0) { return binaryIncrementNeg(val, amount); } return binaryIncrementPos(val, amount); } /* increment/deincrement for positive value */ private static byte[] binaryIncrementPos(byte[] value, long amount) { long amo = amount; int sign = 1; if (amount < 0) { amo = -amount; sign = -1; } for (int i = 0; i < value.length; i++) { int cur = ((int) amo % 256) * sign; amo = (amo >> 8); int val = value[value.length - i - 1] & 0x0ff; int total = val + cur; if (total > 255) { amo += sign; total %= 256; } else if (total < 0) { amo -= sign; } value[value.length - i - 1] = (byte) total; if (amo == 0) return value; } return value; } /* increment/deincrement for negative value */ private static byte[] binaryIncrementNeg(byte[] value, long amount) { long amo = amount; int sign = 1; if (amount < 0) { amo = -amount; sign = -1; } for (int i = 0; i < value.length; i++) { int cur = ((int) amo % 256) * sign; amo = (amo >> 8); int val = ((~value[value.length - i - 1]) & 0x0ff) + 1; int total = cur - val; if (total >= 0) { amo += sign; } else if (total < -256) { amo -= sign; total %= 256; } value[value.length - i - 1] = (byte) total; if (amo == 0) return value; } return value; } /** * Writes a string as a fixed-size field, padded with zeros. */ public static void writeStringFixedSize(final DataOutput out, String s, int size) throws IOException { byte[] b = toBytes(s); if (b.length > size) { throw new IOException("Trying to write " + b.length + " bytes (" + toStringBinary(b) + ") into a field of length " + size); } out.writeBytes(s); for (int i = 0; i < size - s.length(); ++i) out.writeByte(0); } /** * Reads a fixed-size field and interprets it as a string padded with zeros. */ public static String readStringFixedSize(final DataInput in, int size) throws IOException { byte[] b = new byte[size]; in.readFully(b); int n = b.length; while (n > 0 && b[n - 1] == 0) --n; return toString(b, 0, n); } /** * Copy the byte array given in parameter and return an instance of a new byte array with the same * length and the same content. * @param bytes the byte array to duplicate * @return a copy of the given byte array */ public static byte[] copy(byte[] bytes) { if (bytes == null) return null; byte[] result = new byte[bytes.length]; System.arraycopy(bytes, 0, result, 0, bytes.length); return result; } /** * Copy the byte array given in parameter and return an instance of a new byte array with the same * length and the same content. * @param bytes the byte array to copy from * @return a copy of the given designated byte array nn */ public static byte[] copy(byte[] bytes, final int offset, final int length) { if (bytes == null) return null; byte[] result = new byte[length]; System.arraycopy(bytes, offset, result, 0, length); return result; } /** * Search sorted array "a" for byte "key". I can't remember if I wrote this or copied it from * somewhere. (mcorgan) * @param a Array to search. Entries must be sorted and unique. * @param fromIndex First index inclusive of "a" to include in the search. * @param toIndex Last index exclusive of "a" to include in the search. * @param key The byte to search for. * @return The index of key if found. If not found, return -(index + 1), where negative indicates * "not found" and the "index + 1" handles the "-0" case. */ public static int unsignedBinarySearch(byte[] a, int fromIndex, int toIndex, byte key) { int unsignedKey = key & 0xff; int low = fromIndex; int high = toIndex - 1; while (low <= high) { int mid = low + ((high - low) >> 1); int midVal = a[mid] & 0xff; if (midVal < unsignedKey) { low = mid + 1; } else if (midVal > unsignedKey) { high = mid - 1; } else { return mid; // key found } } return -(low + 1); // key not found. } /** * Treat the byte[] as an unsigned series of bytes, most significant bits first. Start by adding 1 * to the rightmost bit/byte and carry over all overflows to the more significant bits/bytes. * @param input The byte[] to increment. * @return The incremented copy of "in". May be same length or 1 byte longer. */ public static byte[] unsignedCopyAndIncrement(final byte[] input) { byte[] copy = copy(input); if (copy == null) { throw new IllegalArgumentException("cannot increment null array"); } for (int i = copy.length - 1; i >= 0; --i) { if (copy[i] == -1) {// -1 is all 1-bits, which is the unsigned maximum copy[i] = 0; } else { ++copy[i]; return copy; } } // we maxed out the array byte[] out = new byte[copy.length + 1]; out[0] = 1; System.arraycopy(copy, 0, out, 1, copy.length); return out; } public static boolean equals(List a, List b) { if (a == null) { if (b == null) { return true; } return false; } if (b == null) { return false; } if (a.size() != b.size()) { return false; } for (int i = 0; i < a.size(); ++i) { if (!Bytes.equals(a.get(i), b.get(i))) { return false; } } return true; } public static boolean isSorted(Collection arrays) { if (!CollectionUtils.isEmpty(arrays)) { byte[] previous = new byte[0]; for (byte[] array : arrays) { if (Bytes.compareTo(previous, array) > 0) { return false; } previous = array; } } return true; } public static List getUtf8ByteArrays(List strings) { if (CollectionUtils.isEmpty(strings)) { return Collections.emptyList(); } List byteArrays = new ArrayList<>(strings.size()); strings.forEach(s -> byteArrays.add(Bytes.toBytes(s))); return byteArrays; } /** * Returns the index of the first appearance of the value {@code target} in {@code array}. * @param array an array of {@code byte} values, possibly empty * @param target a primitive {@code byte} value * @return the least index {@code i} for which {@code array[i] == target}, or {@code -1} if no * such index exists. */ public static int indexOf(byte[] array, byte target) { for (int i = 0; i < array.length; i++) { if (array[i] == target) { return i; } } return -1; } /** * Returns the start position of the first occurrence of the specified {@code * target} within {@code array}, or {@code -1} if there is no such occurrence. *

* More formally, returns the lowest index {@code i} such that {@code * java.util.Arrays.copyOfRange(array, i, i + target.length)} contains exactly the same elements * as {@code target}. * @param array the array to search for the sequence {@code target} * @param target the array to search for as a sub-sequence of {@code array} */ public static int indexOf(byte[] array, byte[] target) { checkNotNull(array, "array"); checkNotNull(target, "target"); if (target.length == 0) { return 0; } outer: for (int i = 0; i < array.length - target.length + 1; i++) { for (int j = 0; j < target.length; j++) { if (array[i + j] != target[j]) { continue outer; } } return i; } return -1; } /** * @param array an array of {@code byte} values, possibly empty * @param target a primitive {@code byte} value * @return {@code true} if {@code target} is present as an element anywhere in {@code array}. */ public static boolean contains(byte[] array, byte target) { return indexOf(array, target) > -1; } /** * @param array an array of {@code byte} values, possibly empty * @param target an array of {@code byte} * @return {@code true} if {@code target} is present anywhere in {@code array} */ public static boolean contains(byte[] array, byte[] target) { return indexOf(array, target) > -1; } /** * Fill given array with zeros. * @param b array which needs to be filled with zeros */ public static void zero(byte[] b) { zero(b, 0, b.length); } /** * Fill given array with zeros at the specified position. nnn */ public static void zero(byte[] b, int offset, int length) { checkPositionIndex(offset, b.length, "offset"); checkArgument(length > 0, "length must be greater than 0"); checkPositionIndex(offset + length, b.length, "offset + length"); Arrays.fill(b, offset, offset + length, (byte) 0); } // Pseudorandom random number generator, do not use SecureRandom here private static final Random RNG = new Random(); /** * Fill given array with random bytes. * @param b array which needs to be filled with random bytes *

* If you want random bytes generated by a strong source of randomness use * {@link Bytes#secureRandom(byte[])}. * @param b array which needs to be filled with random bytes */ public static void random(byte[] b) { RNG.nextBytes(b); } /** * Fill given array with random bytes at the specified position. *

* If you want random bytes generated by a strong source of randomness use * {@link Bytes#secureRandom(byte[], int, int)}. * @param b array which needs to be filled with random bytes * @param offset staring offset in array * @param length number of bytes to fill */ public static void random(byte[] b, int offset, int length) { checkPositionIndex(offset, b.length, "offset"); checkArgument(length > 0, "length must be greater than 0"); checkPositionIndex(offset + length, b.length, "offset + length"); byte[] buf = new byte[length]; RNG.nextBytes(buf); System.arraycopy(buf, 0, b, offset, length); } // Bytes.secureRandom may be used to create key material. private static final SecureRandom SECURE_RNG = new SecureRandom(); /** * Fill given array with random bytes using a strong random number generator. * @param b array which needs to be filled with random bytes */ public static void secureRandom(byte[] b) { SECURE_RNG.nextBytes(b); } /** * Fill given array with random bytes at the specified position using a strong random number * generator. * @param b array which needs to be filled with random bytes * @param offset staring offset in array * @param length number of bytes to fill */ public static void secureRandom(byte[] b, int offset, int length) { checkPositionIndex(offset, b.length, "offset"); checkArgument(length > 0, "length must be greater than 0"); checkPositionIndex(offset + length, b.length, "offset + length"); byte[] buf = new byte[length]; SECURE_RNG.nextBytes(buf); System.arraycopy(buf, 0, b, offset, length); } /** * Create a max byte array with the specified max byte count * @param maxByteCount the length of returned byte array * @return the created max byte array */ public static byte[] createMaxByteArray(int maxByteCount) { byte[] maxByteArray = new byte[maxByteCount]; for (int i = 0; i < maxByteArray.length; i++) { maxByteArray[i] = (byte) 0xff; } return maxByteArray; } /** * Create a byte array which is multiple given bytes nn * @return byte array */ public static byte[] multiple(byte[] srcBytes, int multiNum) { if (multiNum <= 0) { return new byte[0]; } byte[] result = new byte[srcBytes.length * multiNum]; for (int i = 0; i < multiNum; i++) { System.arraycopy(srcBytes, 0, result, i * srcBytes.length, srcBytes.length); } return result; } private static final char[] HEX_CHARS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; /** * Convert a byte range into a hex string */ public static String toHex(byte[] b, int offset, int length) { checkArgument(length <= Integer.MAX_VALUE / 2); int numChars = length * 2; char[] ch = new char[numChars]; for (int i = 0; i < numChars; i += 2) { byte d = b[offset + i / 2]; ch[i] = HEX_CHARS[(d >> 4) & 0x0F]; ch[i + 1] = HEX_CHARS[d & 0x0F]; } return new String(ch); } /** * Convert a byte array into a hex string */ public static String toHex(byte[] b) { return toHex(b, 0, b.length); } private static int hexCharToNibble(char ch) { if (ch <= '9' && ch >= '0') { return ch - '0'; } else if (ch >= 'a' && ch <= 'f') { return ch - 'a' + 10; } else if (ch >= 'A' && ch <= 'F') { return ch - 'A' + 10; } throw new IllegalArgumentException("Invalid hex char: " + ch); } private static byte hexCharsToByte(char c1, char c2) { return (byte) ((hexCharToNibble(c1) << 4) | hexCharToNibble(c2)); } /** * Create a byte array from a string of hash digits. The length of the string must be a multiple * of 2 n */ public static byte[] fromHex(String hex) { checkArgument(hex.length() % 2 == 0, "length must be a multiple of 2"); int len = hex.length(); byte[] b = new byte[len / 2]; for (int i = 0; i < len; i += 2) { b[i / 2] = hexCharsToByte(hex.charAt(i), hex.charAt(i + 1)); } return b; } /** * Find index of passed delimiter. * @return Index of delimiter having started from start of b moving rightward. */ public static int searchDelimiterIndex(final byte[] b, int offset, final int length, final int delimiter) { if (b == null) { throw new IllegalArgumentException("Passed buffer is null"); } int result = -1; for (int i = offset; i < length + offset; i++) { if (b[i] == delimiter) { result = i; break; } } return result; } /** * Find index of passed delimiter walking from end of buffer backwards. * @return Index of delimiter */ public static int searchDelimiterIndexInReverse(final byte[] b, final int offset, final int length, final int delimiter) { if (b == null) { throw new IllegalArgumentException("Passed buffer is null"); } int result = -1; for (int i = (offset + length) - 1; i >= offset; i--) { if (b[i] == delimiter) { result = i; break; } } return result; } public static int findCommonPrefix(byte[] left, byte[] right, int leftLength, int rightLength, int leftOffset, int rightOffset) { int length = Math.min(leftLength, rightLength); int result = 0; while (result < length && left[leftOffset + result] == right[rightOffset + result]) { result++; } return result; } }





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