co.cask.common.Bytes Maven / Gradle / Ivy
/*
* Copyright © 2014 Cask Data, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package co.cask.common;
import com.google.common.base.Charsets;
import com.google.common.collect.ImmutableSortedMap;
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.util.Arrays;
import java.util.Comparator;
import java.util.Iterator;
import java.util.NavigableMap;
import javax.annotation.Nullable;
/**
* Utility class that handles byte arrays, conversions to/from other types,
* comparisons, hash code generation, manufacturing keys for HashMaps or
* HashSets, etc.
*/
@SuppressWarnings("javadoc")
public class Bytes {
/**
* 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;
private static final char[] hexDigits = "0123456789abcdef".toCharArray();
/**
* Byte array comparator class.
*/
public static class ByteArrayComparator implements Comparator {
/**
* Constructor.
*/
public ByteArrayComparator() {
super();
}
@Override
public int compare(byte [] left, byte [] right) {
return compareTo(left, right);
}
}
/**
* Pass this to TreeMaps where byte [] are keys.
*/
public static final Comparator BYTES_COMPARATOR =
new ByteArrayComparator();
/**
* 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;
}
/**
* Returns a new byte array, copied from the passed ByteBuffer.
* @param bb A ByteBuffer
* @return the byte array
*/
public static byte[] toBytes(ByteBuffer bb) {
int length = bb.limit();
byte [] result = new byte[length];
System.arraycopy(bb.array(), bb.arrayOffset(), result, 0, length);
return result;
}
/**
* This method will convert utf8 encoded bytes into a string. If
* an UnsupportedEncodingException occurs, this method will eat it
* and return null instead.
* @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);
}
/**
* When we encode strings, we always specify UTF8 encoding.
*/
public static final String UTF8_ENCODING = "UTF-8";
/**
* This method will convert utf8 encoded bytes into a string. If
* an UnsupportedEncodingException occurs, this method will eat it
* and return null instead.
*
* @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_ENCODING);
} catch (UnsupportedEncodingException e) {
return null;
}
}
/**
* This method will convert the remaining bytes of a UTF8
* encoded byte buffer into a string.
*
* @param buf Presumed UTF-8 encoded byte buffer.
* @return String made from buf or null
*/
public static String toString(ByteBuffer buf) {
if (buf == null) {
return null;
}
buf.mark();
String s = Charsets.UTF_8.decode(buf).toString();
buf.reset();
return s;
}
/**
* Write a printable representation of a byte array.
*
* @param b byte array
* @return string
* @see #toStringBinary(byte[], int, int)
*/
public static String toStringBinary(final byte [] b) {
if (b == null) {
return "null";
}
return toStringBinary(b, 0, b.length);
}
/**
* Returns a string containing each byte, in order, as a two-digit unsigned
* hexadecimal number in lower case.
*/
public static String toHexString(byte [] bytes) {
StringBuilder sb = new StringBuilder(2 * bytes.length);
for (byte b : bytes) {
sb.append(hexDigits[(b >> 4) & 0xf]).append(hexDigits[b & 0xf]);
}
return sb.toString();
}
/**
* Converts the given byte buffer, from its array offset to its limit, to
* a string. The position and the mark are ignored.
*
* @param buf a byte buffer
* @return a string representation of the buffer's binary contents
*/
public static String toStringBinary(ByteBuffer buf) {
if (buf == null) {
return "null";
}
return toStringBinary(buf.array(), buf.arrayOffset(), buf.limit());
}
/**
* 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();
try {
String first = new String(b, off, len, "ISO-8859-1");
for (int i = 0; i < first.length(); ++i) {
int ch = first.charAt(i) & 0xFF;
if ((ch >= '0' && ch <= '9')
|| (ch >= 'A' && ch <= 'Z')
|| (ch >= 'a' && ch <= 'z')
|| " `~!@#$%^&*()-_=+[]{}\\|;:'\",.<>/?".indexOf(ch) >= 0) {
result.append(first.charAt(i));
} else {
result.append(String.format("\\x%02X", ch));
}
}
} catch (UnsupportedEncodingException e) {
}
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 lets 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 == '\\') {
// begin hex escape:
char next = in.charAt(i + 1);
if (next != 'x') {
// invalid escape sequence, ignore this one.
b[size++] = (byte) ch;
continue;
}
// 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_ENCODING);
} catch (UnsupportedEncodingException e) {
return null;
}
}
/**
* 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);
}
long l = 0;
for (int i = offset; i < offset + length; i++) {
l <<= 8;
l ^= bytes[i] & 0xFF;
}
return l;
}
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");
}
for (int i = offset + 7; i > offset; i--) {
bytes[i] = (byte) val;
val >>>= 8;
}
bytes[offset] = (byte) val;
return offset + SIZEOF_LONG;
}
/**
* 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));
}
/**
* Put a float value out to the specified byte array position.
* @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));
}
/**
* Return double made from passed bytes.
* @param bytes byte array
* @return Return double made from passed bytes.
*/
public static double toDouble(final byte [] bytes) {
return toDouble(bytes, 0);
}
/**
* Return double made from passed bytes.
* @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));
}
/**
* Put a double value out to the specified byte array position.
* @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.
* @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);
}
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");
}
for (int i = offset + 3; i > offset; i--) {
bytes[i] = (byte) val;
val >>>= 8;
}
bytes[offset] = (byte) val;
return offset + SIZEOF_INT;
}
/**
* 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);
}
short n = 0;
n ^= bytes[offset] & 0xFF;
n <<= 8;
n ^= bytes[offset + 1] & 0xFF;
return n;
}
/**
* This method will get a sequence of bytes from pos -> limit,
* but will restore pos after.
* @param buf
* @return byte array
*/
public static byte[] getBytes(ByteBuffer buf) {
int savedPos = buf.position();
byte [] newBytes = new byte[buf.remaining()];
buf.get(newBytes);
buf.position(savedPos);
return newBytes;
}
/**
* 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");
}
bytes[offset + 1] = (byte) val;
val >>= 8;
bytes[offset] = (byte) val;
return offset + SIZEOF_SHORT;
}
/**
* Convert a BigDecimal value to a byte array.
*
* @param val
* @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.
*
* @param bytes
* @return the char value
*/
public static BigDecimal toBigDecimal(byte[] bytes) {
return toBigDecimal(bytes, 0, bytes.length);
}
/**
* Converts a byte array to a BigDecimal value.
*
* @param bytes
* @param offset
* @param length
* @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);
}
/**
* Lexicographically compare two arrays.
* @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.length, right, 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 {
public abstract int compareTo(T buffer1, int offset1, int length1, T buffer2, int offset2, int length2);
}
static Comparer lexicographicalComparerJavaImpl() {
return LexicographicalComparerHolder.PureJavaComparer.INSTANCE;
}
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;
}
}
}
/**
* Checks two byte arrays for equality.
* @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;
}
/**
* Checks segments of two byte arrays for equality.
* @param left left operand
* @param leftOffset offset from which to start comparison
* @param leftLen length of left segment
* @param right right operand
* @param rightOffset offset from which to start comparison
* @param rightLen length of right segment
* @return True if two segments are equal
*/
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;
}
/**
* 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;
}
/**
* Compute hash for binary data.
* @param b bytes to hash
* @return Runs {@link #hashBytes(byte[], int)} on the
* passed in array.
*/
public static int hashCode(final byte [] b) {
return hashCode(b, b.length);
}
/**
* Compute hash for binary data.
* @param b value
* @param length length of the value
* @return Runs {@link #hashBytes(byte[], int)} on the
* passed in array.
*/
public static int hashCode(final byte [] b, final int length) {
return hashBytes(b, length);
}
/** Compute hash for binary data. */
public static int hashBytes(byte[] bytes, int offset, int length) {
int hash = 1;
for (int i = offset; i < offset + length; i++) {
hash = (31 * hash) + bytes[i];
}
return hash;
}
/** Compute hash for binary data. */
public static int hashBytes(byte[] bytes, int length) {
return hashBytes(bytes, 0, length);
}
/**
* Returns a hash of a byte array as an Integer that can be used as key in Maps.
* @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);
}
/**
* Returns a hash of a byte array segment as an Integer that can be used as key in Maps.
* @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);
}
/**
* Byte array of size zero.
*/
public static final byte [] EMPTY_BYTE_ARRAY = new byte [0];
/**
* Concatenate two byte arrays.
* @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);
}
/**
* Concatenate three byte arrays.
* @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;
}
/**
* Returns the values from each provided array combined into a single array.
* For example, {@code concat(new byte[] {a, b}, new byte[] {}, new
* byte[] {c}} returns the array {@code {a, b, c}}. This method is copied from google guava library.
*
* @param arrays zero or more {@code byte} arrays
* @return a single array containing all the values from the source arrays, in
* order
*/
public static byte[] concat(byte[]... arrays) {
int length = 0;
for (byte[] array : arrays) {
length += array.length;
}
byte[] result = new byte[length];
int pos = 0;
for (byte[] array : arrays) {
System.arraycopy(array, 0, result, pos, array.length);
pos += array.length;
}
return result;
}
/**
* Returns first length bytes from byte array.
* @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;
}
/**
* Returns last length bytes from byte array.
* @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;
}
/**
* Return a byte array with value in a plus length prepended 0 bytes.
* @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);
}
/**
* Return a byte array with value in a plus length appended 0 bytes.
* @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);
if (diffBI.compareTo(splitsBI) < 0) {
return null;
}
final BigInteger intervalBI;
try {
intervalBI = diffBI.divide(splitsBI);
} catch (Exception e) {
return null;
}
final Iterator iterator = new Iterator() {
private int i = -1;
@Override
public boolean hasNext() {
return this.i < num + 1;
}
@Override
public byte[] next() {
this.i++;
if (this.i == 0) {
return a;
}
if (this.i == num + 1) {
return b;
}
BigInteger curBI = startBI.add(intervalBI.multiply(BigInteger.valueOf(this.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;
}
/**
* Returns an array of byte arrays made from passed array of Text.
* @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;
}
/**
* Returns an array of byte arrays where first and only entry is.
* column
* @param column operand
* @return An array of byte arrays where first and only entry is
* column
*/
public static byte [][] toByteArrays(final String column) {
return toByteArrays(toBytes(column));
}
/**
* Returns an array of byte arrays where first and only entry is.
* column
* @param column operand
* @return An array of byte arrays where first and only entry is
* column
*/
public static byte [][] toByteArrays(final byte [] column) {
byte [][] result = new byte[1][];
result[0] = column;
return result;
}
/**
* 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);
}
}
/**
* Returns the given prefix, incremented by one, in the form that will be suitable for prefix matching.
* @param prefix the prefix to increment for the stop key
* @return the stop key to use (may be null if the prefix cannot be incremented)
*/
// NOTE: null means "read to the end"
@Nullable
public static byte[] stopKeyForPrefix(byte[] prefix) {
for (int i = prefix.length - 1; i >= 0; i--) {
int unsigned = prefix[i] & 0xff;
if (unsigned < 0xff) {
byte[] stopKey = Arrays.copyOf(prefix, i + 1);
stopKey[stopKey.length - 1]++;
return stopKey;
}
}
// i.e. "read to the end"
return null;
}
/**
* Creates immutable sorted map with one entry with given key and value.
* @param key key of the entry
* @param value value of the entry
* @return instance of {@link java.util.NavigableMap}
*/
public static NavigableMap immutableSortedMapOf(byte[] key, T value) {
return ImmutableSortedMap.orderedBy(Bytes.BYTES_COMPARATOR).put(key, value).build();
}
/**
* Creates immutable sorted map with two entries with given keys and values.
* @param key1 key of the first entry
* @param value1 value of the first entry
* @param key2 key of the second entry
* @param value2 value of the second entry
* @return instance of {@link java.util.NavigableMap}
*/
public static NavigableMap immutableSortedMapOf(byte[] key1, T value1,
byte[] key2, T value2) {
return ImmutableSortedMap.orderedBy(Bytes.BYTES_COMPARATOR)
.put(key1, value1)
.put(key2, value2).build();
}
}
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