001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.util;
019
020import static org.apache.hbase.thirdparty.com.google.common.base.Preconditions.checkArgument;
021import static org.apache.hbase.thirdparty.com.google.common.base.Preconditions.checkNotNull;
022import static org.apache.hbase.thirdparty.com.google.common.base.Preconditions.checkPositionIndex;
023
024import java.io.DataInput;
025import java.io.DataOutput;
026import java.io.IOException;
027import java.io.UnsupportedEncodingException;
028import java.math.BigDecimal;
029import java.math.BigInteger;
030import java.nio.ByteBuffer;
031import java.nio.charset.StandardCharsets;
032import java.security.SecureRandom;
033import java.util.ArrayList;
034import java.util.Arrays;
035import java.util.Collection;
036import java.util.Collections;
037import java.util.Comparator;
038import java.util.Iterator;
039import java.util.List;
040import java.util.Random;
041import org.apache.hadoop.hbase.Cell;
042import org.apache.hadoop.hbase.CellComparator;
043import org.apache.hadoop.hbase.unsafe.HBasePlatformDependent;
044import org.apache.hadoop.io.RawComparator;
045import org.apache.hadoop.io.WritableComparator;
046import org.apache.hadoop.io.WritableUtils;
047import org.apache.yetus.audience.InterfaceAudience;
048import org.slf4j.Logger;
049import org.slf4j.LoggerFactory;
050
051import org.apache.hbase.thirdparty.org.apache.commons.collections4.CollectionUtils;
052
053/**
054 * Utility class that handles byte arrays, conversions to/from other types, comparisons, hash code
055 * generation, manufacturing keys for HashMaps or HashSets, and can be used as key in maps or trees.
056 */
057@InterfaceAudience.Public
058@edu.umd.cs.findbugs.annotations.SuppressWarnings(
059    value = "EQ_CHECK_FOR_OPERAND_NOT_COMPATIBLE_WITH_THIS",
060    justification = "It has been like this forever")
061@SuppressWarnings("MixedMutabilityReturnType")
062public class Bytes implements Comparable<Bytes> {
063
064  // Using the charset canonical name for String/byte[] conversions is much
065  // more efficient due to use of cached encoders/decoders.
066  private static final String UTF8_CSN = StandardCharsets.UTF_8.name();
067
068  // HConstants.EMPTY_BYTE_ARRAY should be updated if this changed
069  private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
070
071  private static final Logger LOG = LoggerFactory.getLogger(Bytes.class);
072
073  /**
074   * Size of boolean in bytes
075   */
076  public static final int SIZEOF_BOOLEAN = Byte.SIZE / Byte.SIZE;
077
078  /**
079   * Size of byte in bytes
080   */
081  public static final int SIZEOF_BYTE = SIZEOF_BOOLEAN;
082
083  /**
084   * Size of char in bytes
085   */
086  public static final int SIZEOF_CHAR = Character.SIZE / Byte.SIZE;
087
088  /**
089   * Size of double in bytes
090   */
091  public static final int SIZEOF_DOUBLE = Double.SIZE / Byte.SIZE;
092
093  /**
094   * Size of float in bytes
095   */
096  public static final int SIZEOF_FLOAT = Float.SIZE / Byte.SIZE;
097
098  /**
099   * Size of int in bytes
100   */
101  public static final int SIZEOF_INT = Integer.SIZE / Byte.SIZE;
102
103  /**
104   * Size of long in bytes
105   */
106  public static final int SIZEOF_LONG = Long.SIZE / Byte.SIZE;
107
108  /**
109   * Size of short in bytes
110   */
111  public static final int SIZEOF_SHORT = Short.SIZE / Byte.SIZE;
112
113  /**
114   * Mask to apply to a long to reveal the lower int only. Use like this: int i =
115   * (int)(0xFFFFFFFF00000000L ^ some_long_value);
116   */
117  public static final long MASK_FOR_LOWER_INT_IN_LONG = 0xFFFFFFFF00000000L;
118
119  /**
120   * Estimate of size cost to pay beyond payload in jvm for instance of byte []. Estimate based on
121   * study of jhat and jprofiler numbers.
122   */
123  // JHat says BU is 56 bytes.
124  // SizeOf which uses java.lang.instrument says 24 bytes. (3 longs?)
125  public static final int ESTIMATED_HEAP_TAX = 16;
126
127  static final boolean UNSAFE_UNALIGNED = HBasePlatformDependent.unaligned();
128
129  /**
130   * Returns length of the byte array, returning 0 if the array is null. Useful for calculating
131   * sizes.
132   * @param b byte array, which can be null
133   * @return 0 if b is null, otherwise returns length
134   */
135  final public static int len(byte[] b) {
136    return b == null ? 0 : b.length;
137  }
138
139  private byte[] bytes;
140  private int offset;
141  private int length;
142
143  /**
144   * Create a zero-size sequence.
145   */
146  public Bytes() {
147    super();
148  }
149
150  /**
151   * Create a Bytes using the byte array as the initial value.
152   * @param bytes This array becomes the backing storage for the object.
153   */
154  public Bytes(byte[] bytes) {
155    this(bytes, 0, bytes.length);
156  }
157
158  /**
159   * Set the new Bytes to the contents of the passed <code>ibw</code>.
160   * @param ibw the value to set this Bytes to.
161   */
162  public Bytes(final Bytes ibw) {
163    this(ibw.get(), ibw.getOffset(), ibw.getLength());
164  }
165
166  /**
167   * Set the value to a given byte range
168   * @param bytes  the new byte range to set to
169   * @param offset the offset in newData to start at
170   * @param length the number of bytes in the range
171   */
172  public Bytes(final byte[] bytes, final int offset, final int length) {
173    this.bytes = bytes;
174    this.offset = offset;
175    this.length = length;
176  }
177
178  /**
179   * Get the data from the Bytes.
180   * @return The data is only valid between offset and offset+length.
181   */
182  public byte[] get() {
183    if (this.bytes == null) {
184      throw new IllegalStateException(
185        "Uninitialiized. Null constructor " + "called w/o accompaying readFields invocation");
186    }
187    return this.bytes;
188  }
189
190  /** Use passed bytes as backing array for this instance. */
191  public void set(final byte[] b) {
192    set(b, 0, b.length);
193  }
194
195  /** Use passed bytes as backing array for this instance. */
196  public void set(final byte[] b, final int offset, final int length) {
197    this.bytes = b;
198    this.offset = offset;
199    this.length = length;
200  }
201
202  /** Returns the number of valid bytes in the buffer */
203  public int getLength() {
204    if (this.bytes == null) {
205      throw new IllegalStateException(
206        "Uninitialiized. Null constructor " + "called w/o accompaying readFields invocation");
207    }
208    return this.length;
209  }
210
211  /** Return the offset into the buffer. */
212  public int getOffset() {
213    return this.offset;
214  }
215
216  @Override
217  public int hashCode() {
218    return Bytes.hashCode(bytes, offset, length);
219  }
220
221  /**
222   * Define the sort order of the Bytes.
223   * @param that The other bytes writable
224   * @return Positive if left is bigger than right, 0 if they are equal, and negative if left is
225   *         smaller than right.
226   */
227  @Override
228  public int compareTo(Bytes that) {
229    return BYTES_RAWCOMPARATOR.compare(this.bytes, this.offset, this.length, that.bytes,
230      that.offset, that.length);
231  }
232
233  /**
234   * Compares the bytes in this object to the specified byte array
235   * @return Positive if left is bigger than right, 0 if they are equal, and negative if left is
236   *         smaller than right.
237   */
238  public int compareTo(final byte[] that) {
239    return BYTES_RAWCOMPARATOR.compare(this.bytes, this.offset, this.length, that, 0, that.length);
240  }
241
242  @Override
243  public boolean equals(Object right_obj) {
244    if (right_obj instanceof byte[]) {
245      return compareTo((byte[]) right_obj) == 0;
246    }
247    if (right_obj instanceof Bytes) {
248      return compareTo((Bytes) right_obj) == 0;
249    }
250    return false;
251  }
252
253  @Override
254  public String toString() {
255    return Bytes.toString(bytes, offset, length);
256  }
257
258  /**
259   * Convert a list of byte[] to an array
260   * @param array List of byte [].
261   * @return Array of byte [].
262   */
263  public static byte[][] toArray(final List<byte[]> array) {
264    // List#toArray doesn't work on lists of byte [].
265    byte[][] results = new byte[array.size()][];
266    for (int i = 0; i < array.size(); i++) {
267      results[i] = array.get(i);
268    }
269    return results;
270  }
271
272  /** Returns a copy of the bytes referred to by this writable */
273  public byte[] copyBytes() {
274    return Arrays.copyOfRange(bytes, offset, offset + length);
275  }
276
277  /** Byte array comparator class. */
278  @InterfaceAudience.Public
279  public static class ByteArrayComparator implements RawComparator<byte[]> {
280
281    public ByteArrayComparator() {
282      super();
283    }
284
285    @Override
286    public int compare(byte[] left, byte[] right) {
287      return compareTo(left, right);
288    }
289
290    @Override
291    public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
292      return LexicographicalComparerHolder.BEST_COMPARER.compareTo(b1, s1, l1, b2, s2, l2);
293    }
294  }
295
296  /**
297   * A {@link ByteArrayComparator} that treats the empty array as the largest value. This is useful
298   * for comparing row end keys for regions.
299   */
300  // TODO: unfortunately, HBase uses byte[0] as both start and end keys for region
301  // boundaries. Thus semantically, we should treat empty byte array as the smallest value
302  // while comparing row keys, start keys etc; but as the largest value for comparing
303  // region boundaries for endKeys.
304  @InterfaceAudience.Public
305  public static class RowEndKeyComparator extends ByteArrayComparator {
306    @Override
307    public int compare(byte[] left, byte[] right) {
308      return compare(left, 0, left.length, right, 0, right.length);
309    }
310
311    @Override
312    public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
313      if (b1 == b2 && s1 == s2 && l1 == l2) {
314        return 0;
315      }
316      if (l1 == 0) {
317        return l2; // 0 or positive
318      }
319      if (l2 == 0) {
320        return -1;
321      }
322      return super.compare(b1, s1, l1, b2, s2, l2);
323    }
324  }
325
326  /** Pass this to TreeMaps where byte [] are keys. */
327  public final static Comparator<byte[]> BYTES_COMPARATOR = new ByteArrayComparator();
328
329  /** Use comparing byte arrays, byte-by-byte */
330  public final static RawComparator<byte[]> BYTES_RAWCOMPARATOR = new ByteArrayComparator();
331
332  /**
333   * Read byte-array written with a WritableableUtils.vint prefix.
334   * @param in Input to read from.
335   * @return byte array read off <code>in</code>
336   * @throws IOException e
337   */
338  public static byte[] readByteArray(final DataInput in) throws IOException {
339    int len = WritableUtils.readVInt(in);
340    if (len < 0) {
341      throw new NegativeArraySizeException(Integer.toString(len));
342    }
343    byte[] result = new byte[len];
344    in.readFully(result, 0, len);
345    return result;
346  }
347
348  /**
349   * Read byte-array written with a WritableableUtils.vint prefix. IOException is converted to a
350   * RuntimeException.
351   * @param in Input to read from.
352   * @return byte array read off <code>in</code>
353   */
354  public static byte[] readByteArrayThrowsRuntime(final DataInput in) {
355    try {
356      return readByteArray(in);
357    } catch (Exception e) {
358      throw new RuntimeException(e);
359    }
360  }
361
362  /**
363   * Write byte-array with a WritableableUtils.vint prefix.
364   * @param out output stream to be written to
365   * @param b   array to write
366   * @throws IOException e
367   */
368  public static void writeByteArray(final DataOutput out, final byte[] b) throws IOException {
369    if (b == null) {
370      WritableUtils.writeVInt(out, 0);
371    } else {
372      writeByteArray(out, b, 0, b.length);
373    }
374  }
375
376  /**
377   * Write byte-array to out with a vint length prefix.
378   * @param out    output stream
379   * @param b      array
380   * @param offset offset into array
381   * @param length length past offset
382   * @throws IOException e
383   */
384  public static void writeByteArray(final DataOutput out, final byte[] b, final int offset,
385    final int length) throws IOException {
386    WritableUtils.writeVInt(out, length);
387    out.write(b, offset, length);
388  }
389
390  /**
391   * Write byte-array from src to tgt with a vint length prefix.
392   * @param tgt       target array
393   * @param tgtOffset offset into target array
394   * @param src       source array
395   * @param srcOffset source offset
396   * @param srcLength source length
397   * @return New offset in src array.
398   */
399  public static int writeByteArray(final byte[] tgt, final int tgtOffset, final byte[] src,
400    final int srcOffset, final int srcLength) {
401    byte[] vint = vintToBytes(srcLength);
402    System.arraycopy(vint, 0, tgt, tgtOffset, vint.length);
403    int offset = tgtOffset + vint.length;
404    System.arraycopy(src, srcOffset, tgt, offset, srcLength);
405    return offset + srcLength;
406  }
407
408  /**
409   * Put bytes at the specified byte array position.
410   * @param tgtBytes  the byte array
411   * @param tgtOffset position in the array
412   * @param srcBytes  array to write out
413   * @param srcOffset source offset
414   * @param srcLength source length
415   * @return incremented offset
416   */
417  public static int putBytes(byte[] tgtBytes, int tgtOffset, byte[] srcBytes, int srcOffset,
418    int srcLength) {
419    System.arraycopy(srcBytes, srcOffset, tgtBytes, tgtOffset, srcLength);
420    return tgtOffset + srcLength;
421  }
422
423  /**
424   * Write a single byte out to the specified byte array position.
425   * @param bytes  the byte array
426   * @param offset position in the array
427   * @param b      byte to write out
428   * @return incremented offset
429   */
430  public static int putByte(byte[] bytes, int offset, byte b) {
431    bytes[offset] = b;
432    return offset + 1;
433  }
434
435  /**
436   * Add the whole content of the ByteBuffer to the bytes arrays. The ByteBuffer is modified.
437   * @param bytes  the byte array
438   * @param offset position in the array
439   * @param buf    ByteBuffer to write out
440   * @return incremented offset
441   */
442  public static int putByteBuffer(byte[] bytes, int offset, ByteBuffer buf) {
443    int len = buf.remaining();
444    buf.get(bytes, offset, len);
445    return offset + len;
446  }
447
448  /**
449   * Returns a new byte array, copied from the given {@code buf}, from the index 0 (inclusive) to
450   * the limit (exclusive), regardless of the current position. The position and the other index
451   * parameters are not changed.
452   * @param buf a byte buffer
453   * @return the byte array
454   * @see #getBytes(ByteBuffer)
455   */
456  public static byte[] toBytes(ByteBuffer buf) {
457    ByteBuffer dup = buf.duplicate();
458    dup.position(0);
459    return readBytes(dup);
460  }
461
462  private static byte[] readBytes(ByteBuffer buf) {
463    byte[] result = new byte[buf.remaining()];
464    buf.get(result);
465    return result;
466  }
467
468  /**
469   * Convert a byte[] into a string. Charset is assumed to be UTF-8.
470   * @param b Presumed UTF-8 encoded byte array.
471   * @return String made from <code>b</code>
472   */
473  public static String toString(final byte[] b) {
474    if (b == null) {
475      return null;
476    }
477    return toString(b, 0, b.length);
478  }
479
480  /**
481   * Joins two byte arrays together using a separator.
482   * @param b1  The first byte array.
483   * @param sep The separator to use.
484   * @param b2  The second byte array.
485   */
486  public static String toString(final byte[] b1, String sep, final byte[] b2) {
487    return toString(b1, 0, b1.length) + sep + toString(b2, 0, b2.length);
488  }
489
490  /**
491   * This method will convert utf8 encoded bytes into a string. If the given byte array is null,
492   * this method will return null.
493   * @param b   Presumed UTF-8 encoded byte array.
494   * @param off offset into array
495   * @return String made from <code>b</code> or null
496   */
497  public static String toString(final byte[] b, int off) {
498    if (b == null) {
499      return null;
500    }
501    int len = b.length - off;
502    if (len <= 0) {
503      return "";
504    }
505    try {
506      return new String(b, off, len, UTF8_CSN);
507    } catch (UnsupportedEncodingException e) {
508      // should never happen!
509      throw new IllegalArgumentException("UTF8 encoding is not supported", e);
510    }
511  }
512
513  /**
514   * This method will convert utf8 encoded bytes into a string. If the given byte array is null,
515   * this method will return null.
516   * @param b   Presumed UTF-8 encoded byte array.
517   * @param off offset into array
518   * @param len length of utf-8 sequence
519   * @return String made from <code>b</code> or null
520   */
521  public static String toString(final byte[] b, int off, int len) {
522    if (b == null) {
523      return null;
524    }
525    if (len == 0) {
526      return "";
527    }
528    try {
529      return new String(b, off, len, UTF8_CSN);
530    } catch (UnsupportedEncodingException e) {
531      // should never happen!
532      throw new IllegalArgumentException("UTF8 encoding is not supported", e);
533    }
534  }
535
536  /**
537   * Write a printable representation of a byte array.
538   * @param b byte array
539   * @see #toStringBinary(byte[], int, int)
540   */
541  public static String toStringBinary(final byte[] b) {
542    if (b == null) return "null";
543    return toStringBinary(b, 0, b.length);
544  }
545
546  /**
547   * Converts the given byte buffer to a printable representation, from the index 0 (inclusive) to
548   * the limit (exclusive), regardless of the current position. The position and the other index
549   * parameters are not changed.
550   * @param buf a byte buffer
551   * @return a string representation of the buffer's binary contents
552   * @see #toBytes(ByteBuffer)
553   * @see #getBytes(ByteBuffer)
554   */
555  public static String toStringBinary(ByteBuffer buf) {
556    if (buf == null) return "null";
557    if (buf.hasArray()) {
558      return toStringBinary(buf.array(), buf.arrayOffset(), buf.limit());
559    }
560    return toStringBinary(toBytes(buf));
561  }
562
563  private static final char[] HEX_CHARS_UPPER =
564    { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
565
566  /**
567   * Write a printable representation of a byte array. Non-printable characters are hex escaped in
568   * the format \\x%02X, eg: \x00 \x05 etc
569   * @param b   array to write out
570   * @param off offset to start at
571   * @param len length to write
572   * @return string output
573   */
574  public static String toStringBinary(final byte[] b, int off, int len) {
575    StringBuilder result = new StringBuilder();
576    // Just in case we are passed a 'len' that is > buffer length...
577    if (off >= b.length) return result.toString();
578    if (off + len > b.length) len = b.length - off;
579    for (int i = off; i < off + len; ++i) {
580      int ch = b[i] & 0xFF;
581      if (ch >= ' ' && ch <= '~' && ch != '\\') {
582        result.append((char) ch);
583      } else {
584        result.append("\\x");
585        result.append(HEX_CHARS_UPPER[ch / 0x10]);
586        result.append(HEX_CHARS_UPPER[ch % 0x10]);
587      }
588    }
589    return result.toString();
590  }
591
592  private static boolean isHexDigit(char c) {
593    return (c >= 'A' && c <= 'F') || (c >= '0' && c <= '9');
594  }
595
596  /**
597   * Takes a ASCII digit in the range A-F0-9 and returns the corresponding integer/ordinal value.
598   * @param ch The hex digit.
599   * @return The converted hex value as a byte.
600   */
601  public static byte toBinaryFromHex(byte ch) {
602    if (ch >= 'A' && ch <= 'F') return (byte) ((byte) 10 + (byte) (ch - 'A'));
603    // else
604    return (byte) (ch - '0');
605  }
606
607  public static byte[] toBytesBinary(String in) {
608    // this may be bigger than we need, but let's be safe.
609    byte[] b = new byte[in.length()];
610    int size = 0;
611    for (int i = 0; i < in.length(); ++i) {
612      char ch = in.charAt(i);
613      if (ch == '\\' && in.length() > i + 1 && in.charAt(i + 1) == 'x') {
614        // ok, take next 2 hex digits.
615        char hd1 = in.charAt(i + 2);
616        char hd2 = in.charAt(i + 3);
617
618        // they need to be A-F0-9:
619        if (!isHexDigit(hd1) || !isHexDigit(hd2)) {
620          // bogus escape code, ignore:
621          continue;
622        }
623        // turn hex ASCII digit -> number
624        byte d = (byte) ((toBinaryFromHex((byte) hd1) << 4) + toBinaryFromHex((byte) hd2));
625
626        b[size++] = d;
627        i += 3; // skip 3
628      } else {
629        b[size++] = (byte) ch;
630      }
631    }
632    // resize:
633    byte[] b2 = new byte[size];
634    System.arraycopy(b, 0, b2, 0, size);
635    return b2;
636  }
637
638  /**
639   * Converts a string to a UTF-8 byte array.
640   * @param s string
641   * @return the byte array
642   */
643  public static byte[] toBytes(String s) {
644    try {
645      return s.getBytes(UTF8_CSN);
646    } catch (UnsupportedEncodingException e) {
647      // should never happen!
648      throw new IllegalArgumentException("UTF8 decoding is not supported", e);
649    }
650  }
651
652  /**
653   * Convert a boolean to a byte array. True becomes -1 and false becomes 0.
654   * @param b value
655   * @return <code>b</code> encoded in a byte array.
656   */
657  public static byte[] toBytes(final boolean b) {
658    return new byte[] { b ? (byte) -1 : (byte) 0 };
659  }
660
661  /**
662   * Reverses {@link #toBytes(boolean)}
663   * @param b array
664   * @return True or false.
665   */
666  public static boolean toBoolean(final byte[] b) {
667    if (b.length != 1) {
668      throw new IllegalArgumentException("Array has wrong size: " + b.length);
669    }
670    return b[0] != (byte) 0;
671  }
672
673  /**
674   * Convert a long value to a byte array using big-endian.
675   * @param val value to convert
676   * @return the byte array
677   */
678  public static byte[] toBytes(long val) {
679    byte[] b = new byte[8];
680    for (int i = 7; i > 0; i--) {
681      b[i] = (byte) val;
682      val >>>= 8;
683    }
684    b[0] = (byte) val;
685    return b;
686  }
687
688  /**
689   * Converts a byte array to a long value. Reverses {@link #toBytes(long)}
690   * @param bytes array
691   * @return the long value
692   */
693  public static long toLong(byte[] bytes) {
694    return toLong(bytes, 0, SIZEOF_LONG);
695  }
696
697  /**
698   * Converts a byte array to a long value. Assumes there will be {@link #SIZEOF_LONG} bytes
699   * available.
700   * @param bytes  bytes
701   * @param offset offset
702   * @return the long value
703   */
704  public static long toLong(byte[] bytes, int offset) {
705    return toLong(bytes, offset, SIZEOF_LONG);
706  }
707
708  /**
709   * Converts a byte array to a long value.
710   * @param bytes  array of bytes
711   * @param offset offset into array
712   * @param length length of data (must be {@link #SIZEOF_LONG})
713   * @return the long value
714   * @throws IllegalArgumentException if length is not {@link #SIZEOF_LONG} or if there's not enough
715   *                                  room in the array at the offset indicated.
716   */
717  public static long toLong(byte[] bytes, int offset, final int length) {
718    if (length != SIZEOF_LONG || offset + length > bytes.length) {
719      throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_LONG);
720    }
721    return ConverterHolder.BEST_CONVERTER.toLong(bytes, offset, length);
722  }
723
724  private static IllegalArgumentException explainWrongLengthOrOffset(final byte[] bytes,
725    final int offset, final int length, final int expectedLength) {
726    String reason;
727    if (length != expectedLength) {
728      reason = "Wrong length: " + length + ", expected " + expectedLength;
729    } else {
730      reason = "offset (" + offset + ") + length (" + length + ") exceed the"
731        + " capacity of the array: " + bytes.length;
732    }
733    return new IllegalArgumentException(reason);
734  }
735
736  /**
737   * Put a long value out to the specified byte array position.
738   * @param bytes  the byte array
739   * @param offset position in the array
740   * @param val    long to write out
741   * @return incremented offset
742   * @throws IllegalArgumentException if the byte array given doesn't have enough room at the offset
743   *                                  specified.
744   */
745  public static int putLong(byte[] bytes, int offset, long val) {
746    if (bytes.length - offset < SIZEOF_LONG) {
747      throw new IllegalArgumentException("Not enough room to put a long at" + " offset " + offset
748        + " in a " + bytes.length + " byte array");
749    }
750    return ConverterHolder.BEST_CONVERTER.putLong(bytes, offset, val);
751  }
752
753  /**
754   * Put a float value out to the specified byte array position. Presumes float encoded as IEEE 754
755   * floating-point "single format"
756   * @param bytes byte array
757   * @return Float made from passed byte array.
758   */
759  public static float toFloat(byte[] bytes) {
760    return toFloat(bytes, 0);
761  }
762
763  /**
764   * Put a float value out to the specified byte array position. Presumes float encoded as IEEE 754
765   * floating-point "single format"
766   * @param bytes  array to convert
767   * @param offset offset into array
768   * @return Float made from passed byte array.
769   */
770  public static float toFloat(byte[] bytes, int offset) {
771    return Float.intBitsToFloat(toInt(bytes, offset, SIZEOF_INT));
772  }
773
774  /**
775   * Put a float value out to the specified byte array position.
776   * @param bytes  byte array
777   * @param offset offset to write to
778   * @param f      float value
779   * @return New offset in <code>bytes</code>
780   */
781  public static int putFloat(byte[] bytes, int offset, float f) {
782    return putInt(bytes, offset, Float.floatToRawIntBits(f));
783  }
784
785  /** Return the float represented as byte[] */
786  public static byte[] toBytes(final float f) {
787    // Encode it as int
788    return Bytes.toBytes(Float.floatToRawIntBits(f));
789  }
790
791  /** Return double made from passed bytes. */
792  public static double toDouble(final byte[] bytes) {
793    return toDouble(bytes, 0);
794  }
795
796  /** Return double made from passed bytes. */
797  public static double toDouble(final byte[] bytes, final int offset) {
798    return Double.longBitsToDouble(toLong(bytes, offset, SIZEOF_LONG));
799  }
800
801  /**
802   * Put a double value out to the specified byte array position as the IEEE 754 double format.
803   * @param bytes  byte array
804   * @param offset offset to write to
805   * @param d      value
806   * @return New offset into array <code>bytes</code>
807   */
808  public static int putDouble(byte[] bytes, int offset, double d) {
809    return putLong(bytes, offset, Double.doubleToLongBits(d));
810  }
811
812  /**
813   * Serialize a double as the IEEE 754 double format output. The resultant array will be 8 bytes
814   * long.
815   * @param d value
816   * @return the double represented as byte []
817   */
818  public static byte[] toBytes(final double d) {
819    // Encode it as a long
820    return Bytes.toBytes(Double.doubleToRawLongBits(d));
821  }
822
823  /**
824   * Convert an int value to a byte array. Big-endian. Same as what DataOutputStream.writeInt does.
825   * @param val value
826   * @return the byte array
827   */
828  public static byte[] toBytes(int val) {
829    byte[] b = new byte[4];
830    for (int i = 3; i > 0; i--) {
831      b[i] = (byte) val;
832      val >>>= 8;
833    }
834    b[0] = (byte) val;
835    return b;
836  }
837
838  /**
839   * Converts a byte array to an int value
840   * @param bytes byte array
841   * @return the int value
842   */
843  public static int toInt(byte[] bytes) {
844    return toInt(bytes, 0, SIZEOF_INT);
845  }
846
847  /**
848   * Converts a byte array to an int value
849   * @param bytes  byte array
850   * @param offset offset into array
851   * @return the int value
852   */
853  public static int toInt(byte[] bytes, int offset) {
854    return toInt(bytes, offset, SIZEOF_INT);
855  }
856
857  /**
858   * Converts a byte array to an int value
859   * @param bytes  byte array
860   * @param offset offset into array
861   * @param length length of int (has to be {@link #SIZEOF_INT})
862   * @return the int value
863   * @throws IllegalArgumentException if length is not {@link #SIZEOF_INT} or if there's not enough
864   *                                  room in the array at the offset indicated.
865   */
866  public static int toInt(byte[] bytes, int offset, final int length) {
867    if (length != SIZEOF_INT || offset + length > bytes.length) {
868      throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_INT);
869    }
870    return ConverterHolder.BEST_CONVERTER.toInt(bytes, offset, length);
871  }
872
873  /**
874   * Converts a byte array to an int value
875   * @param bytes  byte array
876   * @param offset offset into array
877   * @param length how many bytes should be considered for creating int
878   * @return the int value
879   * @throws IllegalArgumentException if there's not enough room in the array at the offset
880   *                                  indicated.
881   */
882  public static int readAsInt(byte[] bytes, int offset, final int length) {
883    if (offset + length > bytes.length) {
884      throw new IllegalArgumentException("offset (" + offset + ") + length (" + length
885        + ") exceed the" + " capacity of the array: " + bytes.length);
886    }
887    int n = 0;
888    for (int i = offset; i < (offset + length); i++) {
889      n <<= 8;
890      n ^= bytes[i] & 0xFF;
891    }
892    return n;
893  }
894
895  /**
896   * Put an int value out to the specified byte array position.
897   * @param bytes  the byte array
898   * @param offset position in the array
899   * @param val    int to write out
900   * @return incremented offset
901   * @throws IllegalArgumentException if the byte array given doesn't have enough room at the offset
902   *                                  specified.
903   */
904  public static int putInt(byte[] bytes, int offset, int val) {
905    if (bytes.length - offset < SIZEOF_INT) {
906      throw new IllegalArgumentException("Not enough room to put an int at" + " offset " + offset
907        + " in a " + bytes.length + " byte array");
908    }
909    return ConverterHolder.BEST_CONVERTER.putInt(bytes, offset, val);
910  }
911
912  /**
913   * Convert a short value to a byte array of {@link #SIZEOF_SHORT} bytes long.
914   * @param val value
915   * @return the byte array
916   */
917  public static byte[] toBytes(short val) {
918    byte[] b = new byte[SIZEOF_SHORT];
919    b[1] = (byte) val;
920    val >>= 8;
921    b[0] = (byte) val;
922    return b;
923  }
924
925  /**
926   * Converts a byte array to a short value
927   * @param bytes byte array
928   * @return the short value
929   */
930  public static short toShort(byte[] bytes) {
931    return toShort(bytes, 0, SIZEOF_SHORT);
932  }
933
934  /**
935   * Converts a byte array to a short value
936   * @param bytes  byte array
937   * @param offset offset into array
938   * @return the short value
939   */
940  public static short toShort(byte[] bytes, int offset) {
941    return toShort(bytes, offset, SIZEOF_SHORT);
942  }
943
944  /**
945   * Converts a byte array to a short value
946   * @param bytes  byte array
947   * @param offset offset into array
948   * @param length length, has to be {@link #SIZEOF_SHORT}
949   * @return the short value
950   * @throws IllegalArgumentException if length is not {@link #SIZEOF_SHORT} or if there's not
951   *                                  enough room in the array at the offset indicated.
952   */
953  public static short toShort(byte[] bytes, int offset, final int length) {
954    if (length != SIZEOF_SHORT || offset + length > bytes.length) {
955      throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_SHORT);
956    }
957    return ConverterHolder.BEST_CONVERTER.toShort(bytes, offset, length);
958  }
959
960  /**
961   * Returns a new byte array, copied from the given {@code buf}, from the position (inclusive) to
962   * the limit (exclusive). The position and the other index parameters are not changed.
963   * @param buf a byte buffer
964   * @return the byte array
965   * @see #toBytes(ByteBuffer)
966   */
967  public static byte[] getBytes(ByteBuffer buf) {
968    return readBytes(buf.duplicate());
969  }
970
971  /**
972   * Put a short value out to the specified byte array position.
973   * @param bytes  the byte array
974   * @param offset position in the array
975   * @param val    short to write out
976   * @return incremented offset
977   * @throws IllegalArgumentException if the byte array given doesn't have enough room at the offset
978   *                                  specified.
979   */
980  public static int putShort(byte[] bytes, int offset, short val) {
981    if (bytes.length - offset < SIZEOF_SHORT) {
982      throw new IllegalArgumentException("Not enough room to put a short at" + " offset " + offset
983        + " in a " + bytes.length + " byte array");
984    }
985    return ConverterHolder.BEST_CONVERTER.putShort(bytes, offset, val);
986  }
987
988  /**
989   * Put an int value as short out to the specified byte array position. Only the lower 2 bytes of
990   * the short will be put into the array. The caller of the API need to make sure they will not
991   * loose the value by doing so. This is useful to store an unsigned short which is represented as
992   * int in other parts.
993   * @param bytes  the byte array
994   * @param offset position in the array
995   * @param val    value to write out
996   * @return incremented offset
997   * @throws IllegalArgumentException if the byte array given doesn't have enough room at the offset
998   *                                  specified.
999   */
1000  public static int putAsShort(byte[] bytes, int offset, int val) {
1001    if (bytes.length - offset < SIZEOF_SHORT) {
1002      throw new IllegalArgumentException("Not enough room to put a short at" + " offset " + offset
1003        + " in a " + bytes.length + " byte array");
1004    }
1005    bytes[offset + 1] = (byte) val;
1006    val >>= 8;
1007    bytes[offset] = (byte) val;
1008    return offset + SIZEOF_SHORT;
1009  }
1010
1011  /** Convert a BigDecimal value to a byte array */
1012  public static byte[] toBytes(BigDecimal val) {
1013    byte[] valueBytes = val.unscaledValue().toByteArray();
1014    byte[] result = new byte[valueBytes.length + SIZEOF_INT];
1015    int offset = putInt(result, 0, val.scale());
1016    putBytes(result, offset, valueBytes, 0, valueBytes.length);
1017    return result;
1018  }
1019
1020  /** Converts a byte array to a BigDecimal */
1021  public static BigDecimal toBigDecimal(byte[] bytes) {
1022    return toBigDecimal(bytes, 0, bytes.length);
1023  }
1024
1025  /** Converts a byte array to a BigDecimal value */
1026  public static BigDecimal toBigDecimal(byte[] bytes, int offset, final int length) {
1027    if (bytes == null || length < SIZEOF_INT + 1 || (offset + length > bytes.length)) {
1028      return null;
1029    }
1030
1031    int scale = toInt(bytes, offset);
1032    byte[] tcBytes = new byte[length - SIZEOF_INT];
1033    System.arraycopy(bytes, offset + SIZEOF_INT, tcBytes, 0, length - SIZEOF_INT);
1034    return new BigDecimal(new BigInteger(tcBytes), scale);
1035  }
1036
1037  /**
1038   * Put a BigDecimal value out to the specified byte array position.
1039   * @param bytes  the byte array
1040   * @param offset position in the array
1041   * @param val    BigDecimal to write out
1042   * @return incremented offset
1043   */
1044  public static int putBigDecimal(byte[] bytes, int offset, BigDecimal val) {
1045    if (bytes == null) {
1046      return offset;
1047    }
1048
1049    byte[] valueBytes = val.unscaledValue().toByteArray();
1050    byte[] result = new byte[valueBytes.length + SIZEOF_INT];
1051    offset = putInt(result, offset, val.scale());
1052    return putBytes(result, offset, valueBytes, 0, valueBytes.length);
1053  }
1054
1055  /**
1056   * Encode a long value as a variable length integer.
1057   * @param vint Integer to make a vint of.
1058   * @return Vint as bytes array.
1059   */
1060  public static byte[] vintToBytes(final long vint) {
1061    long i = vint;
1062    int size = WritableUtils.getVIntSize(i);
1063    byte[] result = new byte[size];
1064    int offset = 0;
1065    if (i >= -112 && i <= 127) {
1066      result[offset] = (byte) i;
1067      return result;
1068    }
1069
1070    int len = -112;
1071    if (i < 0) {
1072      i ^= -1L; // take one's complement'
1073      len = -120;
1074    }
1075
1076    long tmp = i;
1077    while (tmp != 0) {
1078      tmp = tmp >> 8;
1079      len--;
1080    }
1081
1082    result[offset++] = (byte) len;
1083
1084    len = (len < -120) ? -(len + 120) : -(len + 112);
1085
1086    for (int idx = len; idx != 0; idx--) {
1087      int shiftbits = (idx - 1) * 8;
1088      long mask = 0xFFL << shiftbits;
1089      result[offset++] = (byte) ((i & mask) >> shiftbits);
1090    }
1091    return result;
1092  }
1093
1094  /**
1095   * Reads a zero-compressed encoded long from input buffer and returns it.
1096   * @param buffer buffer to convert
1097   * @return vint bytes as an integer.
1098   */
1099  public static long bytesToVint(final byte[] buffer) {
1100    int offset = 0;
1101    byte firstByte = buffer[offset++];
1102    int len = WritableUtils.decodeVIntSize(firstByte);
1103    if (len == 1) {
1104      return firstByte;
1105    }
1106    long i = 0;
1107    for (int idx = 0; idx < len - 1; idx++) {
1108      byte b = buffer[offset++];
1109      i = i << 8;
1110      i = i | (b & 0xFF);
1111    }
1112    return (WritableUtils.isNegativeVInt(firstByte) ? ~i : i);
1113  }
1114
1115  /**
1116   * Reads a zero-compressed encoded long from input buffer and returns it.
1117   * @param buffer Binary array
1118   * @param offset Offset into array at which vint begins.
1119   * @return deserialized long from buffer.
1120   */
1121  public static long readAsVLong(final byte[] buffer, final int offset) {
1122    byte firstByte = buffer[offset];
1123    int len = WritableUtils.decodeVIntSize(firstByte);
1124    if (len == 1) {
1125      return firstByte;
1126    }
1127    long i = 0;
1128    for (int idx = 0; idx < len - 1; idx++) {
1129      byte b = buffer[offset + 1 + idx];
1130      i = i << 8;
1131      i = i | (b & 0xFF);
1132    }
1133    return (WritableUtils.isNegativeVInt(firstByte) ? ~i : i);
1134  }
1135
1136  /**
1137   * Lexicographically compare two arrays.
1138   * @param left  left operand
1139   * @param right right operand
1140   * @return 0 if equal, &lt; 0 if left is less than right, etc.
1141   */
1142  public static int compareTo(final byte[] left, final byte[] right) {
1143    return LexicographicalComparerHolder.BEST_COMPARER.compareTo(left, 0,
1144      left == null ? 0 : left.length, right, 0, right == null ? 0 : right.length);
1145  }
1146
1147  /**
1148   * Lexicographically compare two arrays.
1149   * @param buffer1 left operand
1150   * @param buffer2 right operand
1151   * @param offset1 Where to start comparing in the left buffer
1152   * @param offset2 Where to start comparing in the right buffer
1153   * @param length1 How much to compare from the left buffer
1154   * @param length2 How much to compare from the right buffer
1155   * @return 0 if equal, &lt; 0 if left is less than right, etc.
1156   */
1157  public static int compareTo(byte[] buffer1, int offset1, int length1, byte[] buffer2, int offset2,
1158    int length2) {
1159    return LexicographicalComparerHolder.BEST_COMPARER.compareTo(buffer1, offset1, length1, buffer2,
1160      offset2, length2);
1161  }
1162
1163  interface Comparer<T> {
1164    int compareTo(T buffer1, int offset1, int length1, T buffer2, int offset2, int length2);
1165  }
1166
1167  static abstract class Converter {
1168    abstract long toLong(byte[] bytes, int offset, int length);
1169
1170    abstract int putLong(byte[] bytes, int offset, long val);
1171
1172    abstract int toInt(byte[] bytes, int offset, final int length);
1173
1174    abstract int putInt(byte[] bytes, int offset, int val);
1175
1176    abstract short toShort(byte[] bytes, int offset, final int length);
1177
1178    abstract int putShort(byte[] bytes, int offset, short val);
1179
1180  }
1181
1182  static Comparer<byte[]> lexicographicalComparerJavaImpl() {
1183    return LexicographicalComparerHolder.PureJavaComparer.INSTANCE;
1184  }
1185
1186  static class ConverterHolder {
1187    static final String UNSAFE_CONVERTER_NAME =
1188      ConverterHolder.class.getName() + "$UnsafeConverter";
1189
1190    static final Converter BEST_CONVERTER = getBestConverter();
1191
1192    /**
1193     * Returns the Unsafe-using Converter, or falls back to the pure-Java implementation if unable
1194     * to do so.
1195     */
1196    static Converter getBestConverter() {
1197      try {
1198        Class<?> theClass = Class.forName(UNSAFE_CONVERTER_NAME);
1199
1200        // yes, UnsafeComparer does implement Comparer<byte[]>
1201        @SuppressWarnings("unchecked")
1202        Converter converter = (Converter) theClass.getConstructor().newInstance();
1203        return converter;
1204      } catch (Throwable t) { // ensure we really catch *everything*
1205        return PureJavaConverter.INSTANCE;
1206      }
1207    }
1208
1209    protected static final class PureJavaConverter extends Converter {
1210      static final PureJavaConverter INSTANCE = new PureJavaConverter();
1211
1212      private PureJavaConverter() {
1213      }
1214
1215      @Override
1216      long toLong(byte[] bytes, int offset, int length) {
1217        long l = 0;
1218        for (int i = offset; i < offset + length; i++) {
1219          l <<= 8;
1220          l ^= bytes[i] & 0xFF;
1221        }
1222        return l;
1223      }
1224
1225      @Override
1226      int putLong(byte[] bytes, int offset, long val) {
1227        for (int i = offset + 7; i > offset; i--) {
1228          bytes[i] = (byte) val;
1229          val >>>= 8;
1230        }
1231        bytes[offset] = (byte) val;
1232        return offset + SIZEOF_LONG;
1233      }
1234
1235      @Override
1236      int toInt(byte[] bytes, int offset, int length) {
1237        int n = 0;
1238        for (int i = offset; i < (offset + length); i++) {
1239          n <<= 8;
1240          n ^= bytes[i] & 0xFF;
1241        }
1242        return n;
1243      }
1244
1245      @Override
1246      int putInt(byte[] bytes, int offset, int val) {
1247        for (int i = offset + 3; i > offset; i--) {
1248          bytes[i] = (byte) val;
1249          val >>>= 8;
1250        }
1251        bytes[offset] = (byte) val;
1252        return offset + SIZEOF_INT;
1253      }
1254
1255      @Override
1256      short toShort(byte[] bytes, int offset, int length) {
1257        short n = 0;
1258        n = (short) ((n ^ bytes[offset]) & 0xFF);
1259        n = (short) (n << 8);
1260        n ^= (short) (bytes[offset + 1] & 0xFF);
1261        return n;
1262      }
1263
1264      @Override
1265      int putShort(byte[] bytes, int offset, short val) {
1266        bytes[offset + 1] = (byte) val;
1267        val >>= 8;
1268        bytes[offset] = (byte) val;
1269        return offset + SIZEOF_SHORT;
1270      }
1271    }
1272
1273    protected static final class UnsafeConverter extends Converter {
1274
1275      public UnsafeConverter() {
1276      }
1277
1278      static {
1279        if (!UNSAFE_UNALIGNED) {
1280          // It doesn't matter what we throw;
1281          // it's swallowed in getBestComparer().
1282          throw new Error();
1283        }
1284
1285        // sanity check - this should never fail
1286        if (HBasePlatformDependent.arrayIndexScale(byte[].class) != 1) {
1287          throw new AssertionError();
1288        }
1289      }
1290
1291      @Override
1292      long toLong(byte[] bytes, int offset, int length) {
1293        return UnsafeAccess.toLong(bytes, offset);
1294      }
1295
1296      @Override
1297      int putLong(byte[] bytes, int offset, long val) {
1298        return UnsafeAccess.putLong(bytes, offset, val);
1299      }
1300
1301      @Override
1302      int toInt(byte[] bytes, int offset, int length) {
1303        return UnsafeAccess.toInt(bytes, offset);
1304      }
1305
1306      @Override
1307      int putInt(byte[] bytes, int offset, int val) {
1308        return UnsafeAccess.putInt(bytes, offset, val);
1309      }
1310
1311      @Override
1312      short toShort(byte[] bytes, int offset, int length) {
1313        return UnsafeAccess.toShort(bytes, offset);
1314      }
1315
1316      @Override
1317      int putShort(byte[] bytes, int offset, short val) {
1318        return UnsafeAccess.putShort(bytes, offset, val);
1319      }
1320    }
1321  }
1322
1323  /**
1324   * Provides a lexicographical comparer implementation; either a Java implementation or a faster
1325   * implementation based on {@code Unsafe}.
1326   * <p>
1327   * Uses reflection to gracefully fall back to the Java implementation if {@code Unsafe} isn't
1328   * available.
1329   */
1330  static class LexicographicalComparerHolder {
1331    static final String UNSAFE_COMPARER_NAME =
1332      LexicographicalComparerHolder.class.getName() + "$UnsafeComparer";
1333
1334    static final Comparer<byte[]> BEST_COMPARER = getBestComparer();
1335
1336    /**
1337     * Returns the Unsafe-using Comparer, or falls back to the pure-Java implementation if unable to
1338     * do so.
1339     */
1340    static Comparer<byte[]> getBestComparer() {
1341      try {
1342        Class<?> theClass = Class.forName(UNSAFE_COMPARER_NAME);
1343
1344        // yes, UnsafeComparer does implement Comparer<byte[]>
1345        @SuppressWarnings("unchecked")
1346        Comparer<byte[]> comparer = (Comparer<byte[]>) theClass.getEnumConstants()[0];
1347        return comparer;
1348      } catch (Throwable t) { // ensure we really catch *everything*
1349        return lexicographicalComparerJavaImpl();
1350      }
1351    }
1352
1353    enum PureJavaComparer implements Comparer<byte[]> {
1354      INSTANCE;
1355
1356      @Override
1357      public int compareTo(byte[] buffer1, int offset1, int length1, byte[] buffer2, int offset2,
1358        int length2) {
1359        // Short circuit equal case
1360        if (buffer1 == buffer2 && offset1 == offset2 && length1 == length2) {
1361          return 0;
1362        }
1363        // Bring WritableComparator code local
1364        int end1 = offset1 + length1;
1365        int end2 = offset2 + length2;
1366        for (int i = offset1, j = offset2; i < end1 && j < end2; i++, j++) {
1367          int a = (buffer1[i] & 0xff);
1368          int b = (buffer2[j] & 0xff);
1369          if (a != b) {
1370            return a - b;
1371          }
1372        }
1373        return length1 - length2;
1374      }
1375    }
1376
1377    enum UnsafeComparer implements Comparer<byte[]> {
1378      INSTANCE;
1379
1380      static {
1381        if (!UNSAFE_UNALIGNED) {
1382          // It doesn't matter what we throw;
1383          // it's swallowed in getBestComparer().
1384          throw new Error();
1385        }
1386
1387        // sanity check - this should never fail
1388        if (HBasePlatformDependent.arrayIndexScale(byte[].class) != 1) {
1389          throw new AssertionError();
1390        }
1391      }
1392
1393      /**
1394       * Lexicographically compare two arrays.
1395       * @param buffer1 left operand
1396       * @param buffer2 right operand
1397       * @param offset1 Where to start comparing in the left buffer
1398       * @param offset2 Where to start comparing in the right buffer
1399       * @param length1 How much to compare from the left buffer
1400       * @param length2 How much to compare from the right buffer
1401       * @return 0 if equal, < 0 if left is less than right, etc.
1402       */
1403      @Override
1404      public int compareTo(byte[] buffer1, int offset1, int length1, byte[] buffer2, int offset2,
1405        int length2) {
1406
1407        // Short circuit equal case
1408        if (buffer1 == buffer2 && offset1 == offset2 && length1 == length2) {
1409          return 0;
1410        }
1411        final int stride = 8;
1412        final int minLength = Math.min(length1, length2);
1413        int strideLimit = minLength & ~(stride - 1);
1414        final long offset1Adj = offset1 + UnsafeAccess.BYTE_ARRAY_BASE_OFFSET;
1415        final long offset2Adj = offset2 + UnsafeAccess.BYTE_ARRAY_BASE_OFFSET;
1416        int i;
1417
1418        /*
1419         * Compare 8 bytes at a time. Benchmarking on x86 shows a stride of 8 bytes is no slower
1420         * than 4 bytes even on 32-bit. On the other hand, it is substantially faster on 64-bit.
1421         */
1422        for (i = 0; i < strideLimit; i += stride) {
1423          long lw = HBasePlatformDependent.getLong(buffer1, offset1Adj + i);
1424          long rw = HBasePlatformDependent.getLong(buffer2, offset2Adj + i);
1425          if (lw != rw) {
1426            if (!UnsafeAccess.LITTLE_ENDIAN) {
1427              return ((lw + Long.MIN_VALUE) < (rw + Long.MIN_VALUE)) ? -1 : 1;
1428            }
1429
1430            /*
1431             * We want to compare only the first index where left[index] != right[index]. This
1432             * corresponds to the least significant nonzero byte in lw ^ rw, since lw and rw are
1433             * little-endian. Long.numberOfTrailingZeros(diff) tells us the least significant
1434             * nonzero bit, and zeroing out the first three bits of L.nTZ gives us the shift to get
1435             * that least significant nonzero byte. This comparison logic is based on UnsignedBytes
1436             * comparator from guava v21
1437             */
1438            int n = Long.numberOfTrailingZeros(lw ^ rw) & ~0x7;
1439            return ((int) ((lw >>> n) & 0xFF)) - ((int) ((rw >>> n) & 0xFF));
1440          }
1441        }
1442
1443        // The epilogue to cover the last (minLength % stride) elements.
1444        for (; i < minLength; i++) {
1445          int a = (buffer1[offset1 + i] & 0xFF);
1446          int b = (buffer2[offset2 + i] & 0xFF);
1447          if (a != b) {
1448            return a - b;
1449          }
1450        }
1451        return length1 - length2;
1452      }
1453    }
1454  }
1455
1456  /**
1457   * Lexicographically determine the equality of two arrays.
1458   * @param left  left operand
1459   * @param right right operand
1460   * @return True if equal
1461   */
1462  public static boolean equals(final byte[] left, final byte[] right) {
1463    // Could use Arrays.equals?
1464    // noinspection SimplifiableConditionalExpression
1465    if (left == right) return true;
1466    if (left == null || right == null) return false;
1467    if (left.length != right.length) return false;
1468    if (left.length == 0) return true;
1469
1470    // Since we're often comparing adjacent sorted data,
1471    // it's usual to have equal arrays except for the very last byte
1472    // so check that first
1473    if (left[left.length - 1] != right[right.length - 1]) return false;
1474
1475    return compareTo(left, right) == 0;
1476  }
1477
1478  /**
1479   * Lexicographically determine the equality of two arrays.
1480   * @param left        left operand
1481   * @param leftOffset  offset into left operand
1482   * @param leftLen     length of left operand
1483   * @param right       right operand
1484   * @param rightOffset offset into right operand
1485   * @param rightLen    length of right operand
1486   * @return True if equal
1487   */
1488  public static boolean equals(final byte[] left, int leftOffset, int leftLen, final byte[] right,
1489    int rightOffset, int rightLen) {
1490    // short circuit case
1491    if (left == right && leftOffset == rightOffset && leftLen == rightLen) {
1492      return true;
1493    }
1494    // different lengths fast check
1495    if (leftLen != rightLen) {
1496      return false;
1497    }
1498    if (leftLen == 0) {
1499      return true;
1500    }
1501
1502    // Since we're often comparing adjacent sorted data,
1503    // it's usual to have equal arrays except for the very last byte
1504    // so check that first
1505    if (left[leftOffset + leftLen - 1] != right[rightOffset + rightLen - 1]) return false;
1506
1507    return LexicographicalComparerHolder.BEST_COMPARER.compareTo(left, leftOffset, leftLen, right,
1508      rightOffset, rightLen) == 0;
1509  }
1510
1511  /**
1512   * Lexicographically determine the equality of two byte[], one as ByteBuffer.
1513   * @param a   left operand
1514   * @param buf right operand
1515   * @return True if equal
1516   */
1517  public static boolean equals(byte[] a, ByteBuffer buf) {
1518    if (a == null) return buf == null;
1519    if (buf == null) return false;
1520    if (a.length != buf.remaining()) return false;
1521
1522    // Thou shalt not modify the original byte buffer in what should be read only operations.
1523    ByteBuffer b = buf.duplicate();
1524    for (byte anA : a) {
1525      if (anA != b.get()) {
1526        return false;
1527      }
1528    }
1529    return true;
1530  }
1531
1532  /**
1533   * Return true if the byte array on the right is a prefix of the byte array on the left.
1534   */
1535  public static boolean startsWith(byte[] bytes, byte[] prefix) {
1536    return bytes != null && prefix != null && bytes.length >= prefix.length
1537      && LexicographicalComparerHolder.BEST_COMPARER.compareTo(bytes, 0, prefix.length, prefix, 0,
1538        prefix.length) == 0;
1539  }
1540
1541  /**
1542   * Calculate a hash code from a given byte array.
1543   * @param b bytes to hash
1544   * @return Runs {@link WritableComparator#hashBytes(byte[], int)} on the passed in array. This
1545   *         method is what {@link org.apache.hadoop.io.Text} use calculating hash code.
1546   */
1547  public static int hashCode(final byte[] b) {
1548    return hashCode(b, b.length);
1549  }
1550
1551  /**
1552   * Calculate a hash code from a given byte array.
1553   * @param b      value
1554   * @param length length of the value
1555   * @return Runs {@link WritableComparator#hashBytes(byte[], int)} on the passed in array. This
1556   *         method is what {@link org.apache.hadoop.io.Text} use calculating hash code.
1557   */
1558  public static int hashCode(final byte[] b, final int length) {
1559    return WritableComparator.hashBytes(b, length);
1560  }
1561
1562  /**
1563   * Calculate a hash code from a given byte array suitable for use as a key in maps.
1564   * @param b bytes to hash
1565   * @return A hash of <code>b</code> as an Integer that can be used as key in Maps.
1566   */
1567  public static Integer mapKey(final byte[] b) {
1568    return hashCode(b);
1569  }
1570
1571  /**
1572   * Calculate a hash code from a given byte array suitable for use as a key in maps.
1573   * @param b      bytes to hash
1574   * @param length length to hash
1575   * @return A hash of <code>b</code> as an Integer that can be used as key in Maps.
1576   */
1577  public static Integer mapKey(final byte[] b, final int length) {
1578    return hashCode(b, length);
1579  }
1580
1581  /**
1582   * Concatenate byte arrays.
1583   * @param a lower half
1584   * @param b upper half
1585   * @return New array that has a in lower half and b in upper half.
1586   */
1587  public static byte[] add(final byte[] a, final byte[] b) {
1588    return add(a, b, EMPTY_BYTE_ARRAY);
1589  }
1590
1591  /**
1592   * Concatenate byte arrays.
1593   * @param a first third
1594   * @param b second third
1595   * @param c third third
1596   * @return New array made from a, b and c
1597   */
1598  public static byte[] add(final byte[] a, final byte[] b, final byte[] c) {
1599    byte[] result = new byte[a.length + b.length + c.length];
1600    System.arraycopy(a, 0, result, 0, a.length);
1601    System.arraycopy(b, 0, result, a.length, b.length);
1602    System.arraycopy(c, 0, result, a.length + b.length, c.length);
1603    return result;
1604  }
1605
1606  /**
1607   * Concatenate byte arrays.
1608   * @param arrays all the arrays to concatenate together.
1609   * @return New array made from the concatenation of the given arrays.
1610   */
1611  public static byte[] add(final byte[][] arrays) {
1612    int length = 0;
1613    for (int i = 0; i < arrays.length; i++) {
1614      length += arrays[i].length;
1615    }
1616    byte[] result = new byte[length];
1617    int index = 0;
1618    for (int i = 0; i < arrays.length; i++) {
1619      System.arraycopy(arrays[i], 0, result, index, arrays[i].length);
1620      index += arrays[i].length;
1621    }
1622    return result;
1623  }
1624
1625  /**
1626   * Make a new byte array from a subset of bytes at the head of another.
1627   * @param a      array
1628   * @param length amount of bytes to grab
1629   * @return First <code>length</code> bytes from <code>a</code>
1630   */
1631  public static byte[] head(final byte[] a, final int length) {
1632    if (a.length < length) {
1633      return null;
1634    }
1635    byte[] result = new byte[length];
1636    System.arraycopy(a, 0, result, 0, length);
1637    return result;
1638  }
1639
1640  /**
1641   * Make a new byte array from a subset of bytes at the tail of another.
1642   * @param a      array
1643   * @param length amount of bytes to snarf
1644   * @return Last <code>length</code> bytes from <code>a</code>
1645   */
1646  public static byte[] tail(final byte[] a, final int length) {
1647    if (a.length < length) {
1648      return null;
1649    }
1650    byte[] result = new byte[length];
1651    System.arraycopy(a, a.length - length, result, 0, length);
1652    return result;
1653  }
1654
1655  /**
1656   * Make a new byte array from a subset of bytes at the head of another, zero padded as desired.
1657   * @param a      array
1658   * @param length new array size
1659   * @return Value in <code>a</code> plus <code>length</code> prepended 0 bytes
1660   */
1661  public static byte[] padHead(final byte[] a, final int length) {
1662    byte[] padding = new byte[length];
1663    for (int i = 0; i < length; i++) {
1664      padding[i] = 0;
1665    }
1666    return add(padding, a);
1667  }
1668
1669  /**
1670   * Make a new byte array from a subset of bytes at the tail of another, zero padded as desired.
1671   * @param a      array
1672   * @param length new array size
1673   * @return Value in <code>a</code> plus <code>length</code> appended 0 bytes
1674   */
1675  public static byte[] padTail(final byte[] a, final int length) {
1676    byte[] padding = new byte[length];
1677    for (int i = 0; i < length; i++) {
1678      padding[i] = 0;
1679    }
1680    return add(a, padding);
1681  }
1682
1683  /**
1684   * Split passed range. Expensive operation relatively. Uses BigInteger math. Useful splitting
1685   * ranges for MapReduce jobs.
1686   * @param a   Beginning of range
1687   * @param b   End of range
1688   * @param num Number of times to split range. Pass 1 if you want to split the range in two; i.e.
1689   *            one split.
1690   * @return Array of dividing values
1691   */
1692  public static byte[][] split(final byte[] a, final byte[] b, final int num) {
1693    return split(a, b, false, num);
1694  }
1695
1696  /**
1697   * Split passed range. Expensive operation relatively. Uses BigInteger math. Useful splitting
1698   * ranges for MapReduce jobs.
1699   * @param a         Beginning of range
1700   * @param b         End of range
1701   * @param inclusive Whether the end of range is prefix-inclusive or is considered an exclusive
1702   *                  boundary. Automatic splits are generally exclusive and manual splits with an
1703   *                  explicit range utilize an inclusive end of range.
1704   * @param num       Number of times to split range. Pass 1 if you want to split the range in two;
1705   *                  i.e. one split.
1706   * @return Array of dividing values
1707   */
1708  public static byte[][] split(final byte[] a, final byte[] b, boolean inclusive, final int num) {
1709    byte[][] ret = new byte[num + 2][];
1710    int i = 0;
1711    Iterable<byte[]> iter = iterateOnSplits(a, b, inclusive, num);
1712    if (iter == null) return null;
1713    for (byte[] elem : iter) {
1714      ret[i++] = elem;
1715    }
1716    return ret;
1717  }
1718
1719  /**
1720   * Iterate over keys within the passed range, splitting at an [a,b) boundary.
1721   */
1722  public static Iterable<byte[]> iterateOnSplits(final byte[] a, final byte[] b, final int num) {
1723    return iterateOnSplits(a, b, false, num);
1724  }
1725
1726  /**
1727   * Iterate over keys within the passed range.
1728   */
1729  public static Iterable<byte[]> iterateOnSplits(final byte[] a, final byte[] b, boolean inclusive,
1730    final int num) {
1731    byte[] aPadded;
1732    byte[] bPadded;
1733    if (a.length < b.length) {
1734      aPadded = padTail(a, b.length - a.length);
1735      bPadded = b;
1736    } else if (b.length < a.length) {
1737      aPadded = a;
1738      bPadded = padTail(b, a.length - b.length);
1739    } else {
1740      aPadded = a;
1741      bPadded = b;
1742    }
1743    if (compareTo(aPadded, bPadded) >= 0) {
1744      throw new IllegalArgumentException("b <= a");
1745    }
1746    if (num <= 0) {
1747      throw new IllegalArgumentException("num cannot be <= 0");
1748    }
1749    byte[] prependHeader = { 1, 0 };
1750    final BigInteger startBI = new BigInteger(add(prependHeader, aPadded));
1751    final BigInteger stopBI = new BigInteger(add(prependHeader, bPadded));
1752    BigInteger diffBI = stopBI.subtract(startBI);
1753    if (inclusive) {
1754      diffBI = diffBI.add(BigInteger.ONE);
1755    }
1756    final BigInteger splitsBI = BigInteger.valueOf(num + 1);
1757    // when diffBI < splitBI, use an additional byte to increase diffBI
1758    if (diffBI.compareTo(splitsBI) < 0) {
1759      byte[] aPaddedAdditional = new byte[aPadded.length + 1];
1760      byte[] bPaddedAdditional = new byte[bPadded.length + 1];
1761      for (int i = 0; i < aPadded.length; i++) {
1762        aPaddedAdditional[i] = aPadded[i];
1763      }
1764      for (int j = 0; j < bPadded.length; j++) {
1765        bPaddedAdditional[j] = bPadded[j];
1766      }
1767      aPaddedAdditional[aPadded.length] = 0;
1768      bPaddedAdditional[bPadded.length] = 0;
1769      return iterateOnSplits(aPaddedAdditional, bPaddedAdditional, inclusive, num);
1770    }
1771    final BigInteger intervalBI;
1772    try {
1773      intervalBI = diffBI.divide(splitsBI);
1774    } catch (Exception e) {
1775      LOG.error("Exception caught during division", e);
1776      return null;
1777    }
1778
1779    final Iterator<byte[]> iterator = new Iterator<byte[]>() {
1780      private int i = -1;
1781
1782      @Override
1783      public boolean hasNext() {
1784        return i < num + 1;
1785      }
1786
1787      @Override
1788      public byte[] next() {
1789        i++;
1790        if (i == 0) return a;
1791        if (i == num + 1) return b;
1792
1793        BigInteger curBI = startBI.add(intervalBI.multiply(BigInteger.valueOf(i)));
1794        byte[] padded = curBI.toByteArray();
1795        if (padded[1] == 0) padded = tail(padded, padded.length - 2);
1796        else padded = tail(padded, padded.length - 1);
1797        return padded;
1798      }
1799
1800      @Override
1801      public void remove() {
1802        throw new UnsupportedOperationException();
1803      }
1804
1805    };
1806
1807    return new Iterable<byte[]>() {
1808      @Override
1809      public Iterator<byte[]> iterator() {
1810        return iterator;
1811      }
1812    };
1813  }
1814
1815  /**
1816   * Calculate the hash code for a given range of bytes.
1817   * @param bytes  array to hash
1818   * @param offset offset to start from
1819   * @param length length to hash
1820   */
1821  public static int hashCode(byte[] bytes, int offset, int length) {
1822    int hash = 1;
1823    for (int i = offset; i < offset + length; i++)
1824      hash = (31 * hash) + bytes[i];
1825    return hash;
1826  }
1827
1828  /**
1829   * Create an array of byte[] given an array of String.
1830   * @param t operands
1831   * @return Array of byte arrays made from passed array of Text
1832   */
1833  public static byte[][] toByteArrays(final String[] t) {
1834    byte[][] result = new byte[t.length][];
1835    for (int i = 0; i < t.length; i++) {
1836      result[i] = Bytes.toBytes(t[i]);
1837    }
1838    return result;
1839  }
1840
1841  /**
1842   * Create an array of byte[] given an array of String.
1843   * @param t operands
1844   * @return Array of binary byte arrays made from passed array of binary strings
1845   */
1846  public static byte[][] toBinaryByteArrays(final String[] t) {
1847    byte[][] result = new byte[t.length][];
1848    for (int i = 0; i < t.length; i++) {
1849      result[i] = Bytes.toBytesBinary(t[i]);
1850    }
1851    return result;
1852  }
1853
1854  /**
1855   * Create a byte[][] where first and only entry is <code>column</code>
1856   * @param column operand
1857   * @return A byte array of a byte array where first and only entry is <code>column</code>
1858   */
1859  public static byte[][] toByteArrays(final String column) {
1860    return toByteArrays(toBytes(column));
1861  }
1862
1863  /**
1864   * Create a byte[][] where first and only entry is <code>column</code>
1865   * @param column operand
1866   * @return A byte array of a byte array where first and only entry is <code>column</code>
1867   */
1868  public static byte[][] toByteArrays(final byte[] column) {
1869    byte[][] result = new byte[1][];
1870    result[0] = column;
1871    return result;
1872  }
1873
1874  /**
1875   * Binary search for keys in indexes using Bytes.BYTES_RAWCOMPARATOR.
1876   * @param arr    array of byte arrays to search for
1877   * @param key    the key you want to find
1878   * @param offset the offset in the key you want to find
1879   * @param length the length of the key
1880   * @return zero-based index of the key, if the key is present in the array. Otherwise, a value -(i
1881   *         + 1) such that the key is between arr[i - 1] and arr[i] non-inclusively, where i is in
1882   *         [0, i], if we define arr[-1] = -Inf and arr[N] = Inf for an N-element array. The above
1883   *         means that this function can return 2N + 1 different values ranging from -(N + 1) to N
1884   *         - 1.
1885   */
1886  public static int binarySearch(byte[][] arr, byte[] key, int offset, int length) {
1887    int low = 0;
1888    int high = arr.length - 1;
1889
1890    while (low <= high) {
1891      int mid = low + ((high - low) >> 1);
1892      // we have to compare in this order, because the comparator order
1893      // has special logic when the 'left side' is a special key.
1894      int cmp =
1895        Bytes.BYTES_RAWCOMPARATOR.compare(key, offset, length, arr[mid], 0, arr[mid].length);
1896      // key lives above the midpoint
1897      if (cmp > 0) low = mid + 1;
1898      // key lives below the midpoint
1899      else if (cmp < 0) high = mid - 1;
1900      // BAM. how often does this really happen?
1901      else return mid;
1902    }
1903    return -(low + 1);
1904  }
1905
1906  /**
1907   * Binary search for keys in indexes.
1908   * @param arr        array of byte arrays to search for
1909   * @param key        the key you want to find
1910   * @param comparator a comparator to compare.
1911   * @return zero-based index of the key, if the key is present in the array. Otherwise, a value -(i
1912   *         + 1) such that the key is between arr[i - 1] and arr[i] non-inclusively, where i is in
1913   *         [0, i], if we define arr[-1] = -Inf and arr[N] = Inf for an N-element array. The above
1914   *         means that this function can return 2N + 1 different values ranging from -(N + 1) to N
1915   *         - 1.
1916   * @return the index of the block
1917   */
1918  public static int binarySearch(Cell[] arr, Cell key, CellComparator comparator) {
1919    int low = 0;
1920    int high = arr.length - 1;
1921    while (low <= high) {
1922      int mid = low + ((high - low) >> 1);
1923      // we have to compare in this order, because the comparator order
1924      // has special logic when the 'left side' is a special key.
1925      int cmp = comparator.compare(key, arr[mid]);
1926      // key lives above the midpoint
1927      if (cmp > 0) low = mid + 1;
1928      // key lives below the midpoint
1929      else if (cmp < 0) high = mid - 1;
1930      // BAM. how often does this really happen?
1931      else return mid;
1932    }
1933    return -(low + 1);
1934  }
1935
1936  /**
1937   * Bytewise binary increment/deincrement of long contained in byte array on given amount.
1938   * @param value  - array of bytes containing long (length &lt;= SIZEOF_LONG)
1939   * @param amount value will be incremented on (deincremented if negative)
1940   * @return array of bytes containing incremented long (length == SIZEOF_LONG)
1941   */
1942  public static byte[] incrementBytes(byte[] value, long amount) {
1943    byte[] val = value;
1944    if (val.length < SIZEOF_LONG) {
1945      // Hopefully this doesn't happen too often.
1946      byte[] newvalue;
1947      if (val[0] < 0) {
1948        newvalue = new byte[] { -1, -1, -1, -1, -1, -1, -1, -1 };
1949      } else {
1950        newvalue = new byte[SIZEOF_LONG];
1951      }
1952      System.arraycopy(val, 0, newvalue, newvalue.length - val.length, val.length);
1953      val = newvalue;
1954    } else if (val.length > SIZEOF_LONG) {
1955      throw new IllegalArgumentException("Increment Bytes - value too big: " + val.length);
1956    }
1957    if (amount == 0) return val;
1958    if (val[0] < 0) {
1959      return binaryIncrementNeg(val, amount);
1960    }
1961    return binaryIncrementPos(val, amount);
1962  }
1963
1964  /* increment/deincrement for positive value */
1965  private static byte[] binaryIncrementPos(byte[] value, long amount) {
1966    long amo = amount;
1967    int sign = 1;
1968    if (amount < 0) {
1969      amo = -amount;
1970      sign = -1;
1971    }
1972    for (int i = 0; i < value.length; i++) {
1973      int cur = ((int) amo % 256) * sign;
1974      amo = (amo >> 8);
1975      int val = value[value.length - i - 1] & 0x0ff;
1976      int total = val + cur;
1977      if (total > 255) {
1978        amo += sign;
1979        total %= 256;
1980      } else if (total < 0) {
1981        amo -= sign;
1982      }
1983      value[value.length - i - 1] = (byte) total;
1984      if (amo == 0) return value;
1985    }
1986    return value;
1987  }
1988
1989  /* increment/deincrement for negative value */
1990  private static byte[] binaryIncrementNeg(byte[] value, long amount) {
1991    long amo = amount;
1992    int sign = 1;
1993    if (amount < 0) {
1994      amo = -amount;
1995      sign = -1;
1996    }
1997    for (int i = 0; i < value.length; i++) {
1998      int cur = ((int) amo % 256) * sign;
1999      amo = (amo >> 8);
2000      int val = (~value[value.length - i - 1] & 0x0ff) + 1;
2001      int total = cur - val;
2002      if (total >= 0) {
2003        amo += sign;
2004      } else if (total < -256) {
2005        amo -= sign;
2006        total %= 256;
2007      }
2008      value[value.length - i - 1] = (byte) total;
2009      if (amo == 0) return value;
2010    }
2011    return value;
2012  }
2013
2014  /**
2015   * Writes a string as a fixed-size field, padded with zeros.
2016   */
2017  public static void writeStringFixedSize(final DataOutput out, String s, int size)
2018    throws IOException {
2019    byte[] b = toBytes(s);
2020    if (b.length > size) {
2021      throw new IOException("Trying to write " + b.length + " bytes (" + toStringBinary(b)
2022        + ") into a field of length " + size);
2023    }
2024
2025    out.writeBytes(s);
2026    for (int i = 0; i < size - s.length(); ++i)
2027      out.writeByte(0);
2028  }
2029
2030  /**
2031   * Reads a fixed-size field and interprets it as a string padded with zeros.
2032   */
2033  public static String readStringFixedSize(final DataInput in, int size) throws IOException {
2034    byte[] b = new byte[size];
2035    in.readFully(b);
2036    int n = b.length;
2037    while (n > 0 && b[n - 1] == 0)
2038      --n;
2039
2040    return toString(b, 0, n);
2041  }
2042
2043  /**
2044   * Copy the byte array given in parameter and return an instance of a new byte array with the same
2045   * length and the same content.
2046   * @param bytes the byte array to duplicate
2047   * @return a copy of the given byte array
2048   */
2049  public static byte[] copy(byte[] bytes) {
2050    if (bytes == null) return null;
2051    byte[] result = new byte[bytes.length];
2052    System.arraycopy(bytes, 0, result, 0, bytes.length);
2053    return result;
2054  }
2055
2056  /**
2057   * Copy the byte array given in parameter and return an instance of a new byte array with the same
2058   * length and the same content.
2059   * @param bytes the byte array to copy from
2060   * @return a copy of the given designated byte array
2061   */
2062  public static byte[] copy(byte[] bytes, final int offset, final int length) {
2063    if (bytes == null) return null;
2064    byte[] result = new byte[length];
2065    System.arraycopy(bytes, offset, result, 0, length);
2066    return result;
2067  }
2068
2069  /**
2070   * Search sorted array "a" for byte "key". I can't remember if I wrote this or copied it from
2071   * somewhere. (mcorgan)
2072   * @param a         Array to search. Entries must be sorted and unique.
2073   * @param fromIndex First index inclusive of "a" to include in the search.
2074   * @param toIndex   Last index exclusive of "a" to include in the search.
2075   * @param key       The byte to search for.
2076   * @return The index of key if found. If not found, return -(index + 1), where negative indicates
2077   *         "not found" and the "index + 1" handles the "-0" case.
2078   */
2079  public static int unsignedBinarySearch(byte[] a, int fromIndex, int toIndex, byte key) {
2080    int unsignedKey = key & 0xff;
2081    int low = fromIndex;
2082    int high = toIndex - 1;
2083
2084    while (low <= high) {
2085      int mid = low + ((high - low) >> 1);
2086      int midVal = a[mid] & 0xff;
2087
2088      if (midVal < unsignedKey) {
2089        low = mid + 1;
2090      } else if (midVal > unsignedKey) {
2091        high = mid - 1;
2092      } else {
2093        return mid; // key found
2094      }
2095    }
2096    return -(low + 1); // key not found.
2097  }
2098
2099  /**
2100   * Treat the byte[] as an unsigned series of bytes, most significant bits first. Start by adding 1
2101   * to the rightmost bit/byte and carry over all overflows to the more significant bits/bytes.
2102   * @param input The byte[] to increment.
2103   * @return The incremented copy of "in". May be same length or 1 byte longer.
2104   */
2105  public static byte[] unsignedCopyAndIncrement(final byte[] input) {
2106    byte[] copy = copy(input);
2107    if (copy == null) {
2108      throw new IllegalArgumentException("cannot increment null array");
2109    }
2110    for (int i = copy.length - 1; i >= 0; --i) {
2111      if (copy[i] == -1) {// -1 is all 1-bits, which is the unsigned maximum
2112        copy[i] = 0;
2113      } else {
2114        ++copy[i];
2115        return copy;
2116      }
2117    }
2118    // we maxed out the array
2119    byte[] out = new byte[copy.length + 1];
2120    out[0] = 1;
2121    System.arraycopy(copy, 0, out, 1, copy.length);
2122    return out;
2123  }
2124
2125  public static boolean equals(List<byte[]> a, List<byte[]> b) {
2126    if (a == null) {
2127      if (b == null) {
2128        return true;
2129      }
2130      return false;
2131    }
2132    if (b == null) {
2133      return false;
2134    }
2135    if (a.size() != b.size()) {
2136      return false;
2137    }
2138    for (int i = 0; i < a.size(); ++i) {
2139      if (!Bytes.equals(a.get(i), b.get(i))) {
2140        return false;
2141      }
2142    }
2143    return true;
2144  }
2145
2146  public static boolean isSorted(Collection<byte[]> arrays) {
2147    if (!CollectionUtils.isEmpty(arrays)) {
2148      byte[] previous = new byte[0];
2149      for (byte[] array : arrays) {
2150        if (Bytes.compareTo(previous, array) > 0) {
2151          return false;
2152        }
2153        previous = array;
2154      }
2155    }
2156    return true;
2157  }
2158
2159  public static List<byte[]> getUtf8ByteArrays(List<String> strings) {
2160    if (CollectionUtils.isEmpty(strings)) {
2161      return Collections.emptyList();
2162    }
2163    List<byte[]> byteArrays = new ArrayList<>(strings.size());
2164    strings.forEach(s -> byteArrays.add(Bytes.toBytes(s)));
2165    return byteArrays;
2166  }
2167
2168  /**
2169   * Returns the index of the first appearance of the value {@code target} in {@code array}.
2170   * @param array  an array of {@code byte} values, possibly empty
2171   * @param target a primitive {@code byte} value
2172   * @return the least index {@code i} for which {@code array[i] == target}, or {@code -1} if no
2173   *         such index exists.
2174   */
2175  public static int indexOf(byte[] array, byte target) {
2176    for (int i = 0; i < array.length; i++) {
2177      if (array[i] == target) {
2178        return i;
2179      }
2180    }
2181    return -1;
2182  }
2183
2184  /**
2185   * Returns the start position of the first occurrence of the specified {@code
2186   * target} within {@code array}, or {@code -1} if there is no such occurrence.
2187   * <p>
2188   * More formally, returns the lowest index {@code i} such that {@code
2189   * java.util.Arrays.copyOfRange(array, i, i + target.length)} contains exactly the same elements
2190   * as {@code target}.
2191   * @param array  the array to search for the sequence {@code target}
2192   * @param target the array to search for as a sub-sequence of {@code array}
2193   */
2194  public static int indexOf(byte[] array, byte[] target) {
2195    checkNotNull(array, "array");
2196    checkNotNull(target, "target");
2197    if (target.length == 0) {
2198      return 0;
2199    }
2200
2201    outer: for (int i = 0; i < array.length - target.length + 1; i++) {
2202      for (int j = 0; j < target.length; j++) {
2203        if (array[i + j] != target[j]) {
2204          continue outer;
2205        }
2206      }
2207      return i;
2208    }
2209    return -1;
2210  }
2211
2212  /**
2213   * Return true if target is present as an element anywhere in the given array.
2214   * @param array  an array of {@code byte} values, possibly empty
2215   * @param target a primitive {@code byte} value
2216   * @return {@code true} if {@code target} is present as an element anywhere in {@code array}.
2217   */
2218  public static boolean contains(byte[] array, byte target) {
2219    return indexOf(array, target) > -1;
2220  }
2221
2222  /**
2223   * Return true if target is present as an element anywhere in the given array.
2224   * @param array  an array of {@code byte} values, possibly empty
2225   * @param target an array of {@code byte}
2226   * @return {@code true} if {@code target} is present anywhere in {@code array}
2227   */
2228  public static boolean contains(byte[] array, byte[] target) {
2229    return indexOf(array, target) > -1;
2230  }
2231
2232  /**
2233   * Fill given array with zeros.
2234   * @param b array which needs to be filled with zeros
2235   */
2236  public static void zero(byte[] b) {
2237    zero(b, 0, b.length);
2238  }
2239
2240  /**
2241   * Fill given array with zeros at the specified position.
2242   */
2243  public static void zero(byte[] b, int offset, int length) {
2244    checkPositionIndex(offset, b.length, "offset");
2245    checkArgument(length > 0, "length must be greater than 0");
2246    checkPositionIndex(offset + length, b.length, "offset + length");
2247    Arrays.fill(b, offset, offset + length, (byte) 0);
2248  }
2249
2250  // Pseudorandom random number generator, do not use SecureRandom here
2251  private static final Random RNG = new Random();
2252
2253  /**
2254   * Fill given array with random bytes.
2255   * @param b array which needs to be filled with random bytes
2256   *          <p>
2257   *          If you want random bytes generated by a strong source of randomness use
2258   *          {@link Bytes#secureRandom(byte[])}.
2259   * @param b array which needs to be filled with random bytes
2260   */
2261  public static void random(byte[] b) {
2262    RNG.nextBytes(b);
2263  }
2264
2265  /**
2266   * Fill given array with random bytes at the specified position.
2267   * <p>
2268   * If you want random bytes generated by a strong source of randomness use
2269   * {@link Bytes#secureRandom(byte[], int, int)}.
2270   * @param b      array which needs to be filled with random bytes
2271   * @param offset staring offset in array
2272   * @param length number of bytes to fill
2273   */
2274  public static void random(byte[] b, int offset, int length) {
2275    checkPositionIndex(offset, b.length, "offset");
2276    checkArgument(length > 0, "length must be greater than 0");
2277    checkPositionIndex(offset + length, b.length, "offset + length");
2278    byte[] buf = new byte[length];
2279    RNG.nextBytes(buf);
2280    System.arraycopy(buf, 0, b, offset, length);
2281  }
2282
2283  // Bytes.secureRandom may be used to create key material.
2284  private static final SecureRandom SECURE_RNG = new SecureRandom();
2285
2286  /**
2287   * Fill given array with random bytes using a strong random number generator.
2288   * @param b array which needs to be filled with random bytes
2289   */
2290  public static void secureRandom(byte[] b) {
2291    SECURE_RNG.nextBytes(b);
2292  }
2293
2294  /**
2295   * Fill given array with random bytes at the specified position using a strong random number
2296   * generator.
2297   * @param b      array which needs to be filled with random bytes
2298   * @param offset staring offset in array
2299   * @param length number of bytes to fill
2300   */
2301  public static void secureRandom(byte[] b, int offset, int length) {
2302    checkPositionIndex(offset, b.length, "offset");
2303    checkArgument(length > 0, "length must be greater than 0");
2304    checkPositionIndex(offset + length, b.length, "offset + length");
2305    byte[] buf = new byte[length];
2306    SECURE_RNG.nextBytes(buf);
2307    System.arraycopy(buf, 0, b, offset, length);
2308  }
2309
2310  /**
2311   * Create a max byte array with the specified max byte count
2312   * @param maxByteCount the length of returned byte array
2313   * @return the created max byte array
2314   */
2315  public static byte[] createMaxByteArray(int maxByteCount) {
2316    byte[] maxByteArray = new byte[maxByteCount];
2317    for (int i = 0; i < maxByteArray.length; i++) {
2318      maxByteArray[i] = (byte) 0xff;
2319    }
2320    return maxByteArray;
2321  }
2322
2323  /**
2324   * Create a byte array which is multiple given bytes
2325   * @return byte array
2326   */
2327  public static byte[] multiple(byte[] srcBytes, int multiNum) {
2328    if (multiNum <= 0) {
2329      return new byte[0];
2330    }
2331    byte[] result = new byte[srcBytes.length * multiNum];
2332    for (int i = 0; i < multiNum; i++) {
2333      System.arraycopy(srcBytes, 0, result, i * srcBytes.length, srcBytes.length);
2334    }
2335    return result;
2336  }
2337
2338  private static final char[] HEX_CHARS =
2339    { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
2340
2341  /**
2342   * Convert a byte range into a hex string
2343   */
2344  public static String toHex(byte[] b, int offset, int length) {
2345    checkArgument(length <= Integer.MAX_VALUE / 2);
2346    int numChars = length * 2;
2347    char[] ch = new char[numChars];
2348    for (int i = 0; i < numChars; i += 2) {
2349      byte d = b[offset + i / 2];
2350      ch[i] = HEX_CHARS[(d >> 4) & 0x0F];
2351      ch[i + 1] = HEX_CHARS[d & 0x0F];
2352    }
2353    return new String(ch);
2354  }
2355
2356  /**
2357   * Convert a byte array into a hex string
2358   */
2359  public static String toHex(byte[] b) {
2360    return toHex(b, 0, b.length);
2361  }
2362
2363  private static int hexCharToNibble(char ch) {
2364    if (ch <= '9' && ch >= '0') {
2365      return ch - '0';
2366    } else if (ch >= 'a' && ch <= 'f') {
2367      return ch - 'a' + 10;
2368    } else if (ch >= 'A' && ch <= 'F') {
2369      return ch - 'A' + 10;
2370    }
2371    throw new IllegalArgumentException("Invalid hex char: " + ch);
2372  }
2373
2374  private static byte hexCharsToByte(char c1, char c2) {
2375    return (byte) ((hexCharToNibble(c1) << 4) | hexCharToNibble(c2));
2376  }
2377
2378  /**
2379   * Create a byte array from a string of hash digits. The length of the string must be a multiple
2380   * of 2
2381   */
2382  public static byte[] fromHex(String hex) {
2383    checkArgument(hex.length() % 2 == 0, "length must be a multiple of 2");
2384    int len = hex.length();
2385    byte[] b = new byte[len / 2];
2386    for (int i = 0; i < len; i += 2) {
2387      b[i / 2] = hexCharsToByte(hex.charAt(i), hex.charAt(i + 1));
2388    }
2389    return b;
2390  }
2391
2392  /**
2393   * Find index of passed delimiter.
2394   * @return Index of delimiter having started from start of <code>b</code> moving rightward.
2395   */
2396  public static int searchDelimiterIndex(final byte[] b, int offset, final int length,
2397    final int delimiter) {
2398    if (b == null) {
2399      throw new IllegalArgumentException("Passed buffer is null");
2400    }
2401    int result = -1;
2402    for (int i = offset; i < length + offset; i++) {
2403      if (b[i] == delimiter) {
2404        result = i;
2405        break;
2406      }
2407    }
2408    return result;
2409  }
2410
2411  /**
2412   * Find index of passed delimiter walking from end of buffer backwards.
2413   * @return Index of delimiter
2414   */
2415  public static int searchDelimiterIndexInReverse(final byte[] b, final int offset,
2416    final int length, final int delimiter) {
2417    if (b == null) {
2418      throw new IllegalArgumentException("Passed buffer is null");
2419    }
2420    int result = -1;
2421    for (int i = (offset + length) - 1; i >= offset; i--) {
2422      if (b[i] == delimiter) {
2423        result = i;
2424        break;
2425      }
2426    }
2427    return result;
2428  }
2429
2430  public static int findCommonPrefix(byte[] left, byte[] right, int leftLength, int rightLength,
2431    int leftOffset, int rightOffset) {
2432    int length = Math.min(leftLength, rightLength);
2433    int result = 0;
2434
2435    while (result < length && left[leftOffset + result] == right[rightOffset + result]) {
2436      result++;
2437    }
2438    return result;
2439  }
2440}