JAva各基本タイプ回転bytes配列
1.大端フォーマットの下で、基本タイプはbyte[]と互いに回転する BigByteUtil.java
package com.ysq.util;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.Charset;
import java.util.logging.Logger;
/**
* byte
* @author admin
*
*/
public class BigByteUtil {
static Logger logger = Logger.getLogger(BigByteUtil.class.getName());
/**
* short byte[]
*
* @param data
* @return
*/
public static byte[] getShortBytes(short data) {
ByteBuffer buffer = ByteBuffer.allocate(2);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.putShort(data);
byte[] bytes = buffer.array();
return bytes;
}
/**
* chart byte[]
*
* @param data
* @return
*/
public static byte[] getCharBytes(char data) {
ByteBuffer buffer = ByteBuffer.allocate(2);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.putChar(data);
byte[] bytes = buffer.array();
return bytes;
}
/**
* int byte[]
*
* @param data
* @return
*/
public static byte[] getIntBytes(int data) {
ByteBuffer buffer = ByteBuffer.allocate(4);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.putInt(data);
byte[] bytes = buffer.array();
return bytes;
}
/**
* long byte[]
*
* @param data
* @return
*/
public static byte[] getLongBytes(long data) {
ByteBuffer buffer = ByteBuffer.allocate(8);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.putLong(data);
byte[] bytes = buffer.array();
return bytes;
}
/**
* float byte[]
*
* @param data
* @return
*/
public static byte[] getFloatBytes(float data) {
ByteBuffer buffer = ByteBuffer.allocate(4);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.putFloat(data);
byte[] bytes = buffer.array();
return bytes;
}
/**
* double byte[]
*
* @param data
* @return
*/
public static byte[] getDoubleBytes(double data) {
ByteBuffer buffer = ByteBuffer.allocate(8);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.putDouble(data);
byte[] bytes = buffer.array();
return bytes;
}
/**
* String byte[]
*
* @param data
* @param charsetName
* @return
*/
public static byte[] getStringBytes(String data, String charsetName) {
Charset charset = Charset.forName(charsetName);
byte[] bytes = data.getBytes(charset);
return bytes;
}
/**
* String byte[]
*
* @param data
* @return
*/
public static byte[] getStringBytes(String data) {
byte[] bytes = null;
if(data != null){
bytes = data.getBytes();
}else{
bytes = new byte[0];
}
return bytes;
}
/*****************************************************************************************************************************/
/**
* byte[] short
*
* @param bytes
* @return
*/
public static short getShort(byte[] bytes) {
ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.put(bytes);
short result = buffer.getShort(0);
return result;
}
/**
* byte[] char
*
* @param bytes
* @return
*/
public static char getChar(byte[] bytes) {
ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.put(bytes);
char result = buffer.getChar(0);
return result;
}
/**
* byte[] int
*
* @param bytes
* @return
*/
public static int getInt(byte[] bytes) {
ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.put(bytes);
int result = buffer.getInt(0);
return result;
}
/**
* byte[] long
*
* @param bytes
* @return
*/
public static long getLong(byte[] bytes) {
ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.put(bytes);
long result = buffer.getLong(0);
return result;
}
/**
* byte[] float
*
* @param bytes
* @return
*/
public static float getFloat(byte[] bytes) {
ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.put(bytes);
float result = buffer.getFloat(0);
return result;
}
/**
* byte[] double
*
* @param bytes
* @return
*/
public static double getDouble(byte[] bytes) {
ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
buffer.order(ByteOrder.BIG_ENDIAN);
buffer.put(bytes);
double result = buffer.getDouble(0);
return result;
}
/**
* byte[] String
*
* @param bytes
* @param charsetName
* @return
*/
public static String getString(byte[] bytes, String charsetName) {
String result = new String(bytes, Charset.forName(charsetName));
return result;
}
/**
* byte[] String
*
* @param bytes
* @return
*/
public static String getString(byte[] bytes) {
String result = new String(bytes);
return result;
}
/**
*
*/
private static void verifiTest(){
short s = 1111;
int i = 2222;
long l = 333333;
char c = 'c';
float f = 444.44f;
double d = 555.55;
String string = " 666";
System.out.println(s);
System.out.println(i);
System.out.println(l);
System.out.println(c);
System.out.println(f);
System.out.println(d);
System.out.println(string);
System.out.println("**************");
System.out.println(getShort(getShortBytes(s)));
System.out.println(getInt(getIntBytes(i)));
System.out.println(getLong(getLongBytes(l)));
System.out.println(getChar(getCharBytes(c)));
System.out.println(getFloat(getFloatBytes(f)));
System.out.println(getDouble(getDoubleBytes(d)));
System.out.println(getString(getStringBytes(string)));
}
public static void main(String[] args) {
verifiTest();
System.out.println("finished ... ");
}
}
2. 小端フォーマットでは、基本タイプはbyte[]と相互に回転します. LittleByteUtil.java
二つの方法は効率的にあまり差がない.
package com.ysq.util;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.logging.Logger;
/**
*
* java byte[]
*
* @author admin
*
*/
public class LittleByteUtil {
static Logger logger = Logger.getLogger(LittleByteUtil.class.getName());
static final long fx = 0xffl;
/**
* short byte[]
*
* @param data
* @return
*/
public static byte[] getShortBytes(short data) {
byte[] bytes = new byte[2];
bytes[0] = (byte) (data & fx);
bytes[1] = (byte) ((data >> 8) & fx);
return bytes;
}
/**
* chart byte[]
*
* @param data
* @return
*/
public static byte[] getCharBytes(char data) {
byte[] bytes = new byte[2];
bytes[0] = (byte) (data & fx);
bytes[1] = (byte) ((data >> 8) & fx);
return bytes;
}
/**
* int byte[]
*
* @param data
* @return
*/
public static byte[] getIntBytes(int data) {
int length = 4;
byte[] bytes = new byte[length];
for (int i = 0; i < length; i++) {
bytes[i] = (byte) ((data >> (i*8)) & fx);
}
return bytes;
}
/**
* long byte[]
*
* @param data
* @return
*/
public static byte[] getLongBytes(long data) {
int length = 8;
byte[] bytes = new byte[length];
for (int i = 0; i < length; i++) {
bytes[i] = (byte) ((data >> (i*8)) & fx);
}
return bytes;
}
/**
* float byte[]
*
* @param data
* @return
*/
public static byte[] getFloatBytes(float data) {
int intBits = Float.floatToIntBits(data);
byte[] bytes = getIntBytes(intBits);
return bytes;
}
/**
* double byte[]
*
* @param data
* @return
*/
public static byte[] getDoubleBytes(double data) {
long intBits = Double.doubleToLongBits(data);
byte[] bytes = getLongBytes(intBits);
return bytes;
}
/**
* String byte[]
*
* @param data
* @param charsetName
* @return
*/
public static byte[] getStringBytes(String data, String charsetName) {
Charset charset = Charset.forName(charsetName);
byte[] bytes = data.getBytes(charset);
return bytes;
}
/**
* String byte[]
*
* @param data
* @return
*/
public static byte[] getStringBytes(String data) {
byte[] bytes = null;
if(data != null){
bytes = data.getBytes();
}else{
bytes = new byte[0];
}
return bytes;
}
/**
* byte[] short
*
* @param bytes
* @return
*/
public static short getShort(byte[] bytes) {
short result = (short) ((fx & bytes[0])
| ((fx & bytes[1]) << 8));
return result;
}
/**
* byte[] char
*
* @param bytes
* @return
*/
public static char getChar(byte[] bytes) {
char result = (char) ((fx & bytes[0])
| ((fx & bytes[1]) << 8));
return result;
}
/**
* byte[] int
*
* @param bytes
* @return
*/
public static int getInt(byte[] bytes) {
int result = (int) ((fx & bytes[0])
| ((fx & bytes[1]) << 8)
| ((fx & bytes[2]) << 16)
| ((fx & bytes[3]) << 24));
return result;
}
/**
* byte[] long
*
* @param bytes
* @return
*/
public static long getLong(byte[] bytes) {
long result = (long)((long)(fx & bytes[0])
| (long)((fx & bytes[1]) << 8)
| (long)((fx & bytes[2]) << 16)
| (long)((fx & bytes[3]) << 24)
| (long)((fx & bytes[4]) << 32)
| (long)((fx & bytes[5]) << 40)
| (long)((fx & bytes[6]) << 48)
| (long)((fx & bytes[7]) << 56));
return result;
}
/**
* byte[] float
*
* @param bytes
* @return
*/
public static float getFloat(byte[] b) {
int l = getInt(b);
return Float.intBitsToFloat(l);
}
/**
* byte[] double
*
* @param bytes
* @return
*/
public static double getDouble(byte[] bytes) {
long l = getLong(bytes);
return Double.longBitsToDouble(l);
}
/**
* byte[] String
*
* @param bytes
* @param charsetName
* @return
*/
public static String getString(byte[] bytes, String charsetName) {
String result = new String(bytes, Charset.forName(charsetName));
return result;
}
/**
* byte[] String
*
* @param bytes
* @return
*/
public static String getString(byte[] bytes) {
String result = new String(bytes);
return result;
}
/**
*
*
* @param target
* @param append
* @return
*/
public static byte[] appendByte(byte[] target, byte[] append) {
int originalLength = target.length;
int appendLength = append.length;
//
int totalLength = originalLength + appendLength;
target = Arrays.copyOf(target, totalLength);
System.arraycopy(append, 0, target, originalLength, appendLength);
return target;
}
/**
*
*/
private static void verifiTest(){
short s = 1111;
int i = 2222;
long l = 333333;
char c = 'c';
float f = 444.44f;
double d = 555.55;
String string = " 666";
System.out.println(s);
System.out.println(i);
System.out.println(l);
System.out.println(c);
System.out.println(f);
System.out.println(d);
System.out.println(string);
System.out.println("**************");
System.out.println(getShort(getShortBytes(s)));
System.out.println(getInt(getIntBytes(i)));
System.out.println(getLong(getLongBytes(l)));
System.out.println(getChar(getCharBytes(c)));
System.out.println(getFloat(getFloatBytes(f)));
System.out.println(getDouble(getDoubleBytes(d)));
System.out.println(getString(getStringBytes(string)));
}
private static void bufferTest(){
long a = 4648097885297469030l;
ByteBuffer buf = ByteBuffer.allocate(8);
buf.order(ByteOrder.LITTLE_ENDIAN);
buf.putLong(a);
byte[] bufByte = buf.array();
byte[] bytes = getLongBytes(a);
long ba = getLong(bytes);
System.out.println(bufByte.equals(ba));
System.out.println(ba);
}
public static void main(String[] args) {
verifiTest();
bufferTest();
System.out.println("finished ... ");
}
}
3. hbaseパッケージにもBytesツールクラスがあり使いやすいですが、hbaseは多くのものに依存しているので、hbaseのBytesツールクラスを抽出し、大端小段適応を実現できますが、効率的には上記の方法に及ばず、初期化が遅く、この方法はお勧めできませんが、ここで彼を載せます
ソース:
package com.ysq.util;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.Charset;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Iterator;
import java.util.logging.Level;
import java.util.logging.Logger;
import sun.misc.Unsafe;
import com.ysq.util.BytesUtil.LexicographicalComparerHolder.UnsafeComparer;
/**
* Utility class that handles byte arrays, conversions to/from other types,
* comparisons, hash code generation, manufacturing keys for HashMaps or
* HashSets, etc.
*/
@SuppressWarnings("restriction")
public class BytesUtil {
static Logger logger = Logger.getLogger(BytesUtil.class.getName());
// HConstants.UTF8_ENCODING should be updated if this changed
/** When we encode strings, we always specify UTF8 encoding */
private static final String UTF8_ENCODING = "UTF-8";
// HConstants.UTF8_CHARSET should be updated if this changed
/** When we encode strings, we always specify UTF8 encoding */
private static final Charset UTF8_CHARSET = Charset.forName(UTF8_ENCODING);
// HConstants.EMPTY_BYTE_ARRAY should be updated if this changed
private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
// private static final Log LOG = LogFactory.getLog(Bytes.class);
/**
* Size of boolean in bytes
*/
public static final int SIZEOF_BOOLEAN = Byte.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 boolean UNSAFE_UNALIGNED = UnsafeAvailChecker.unaligned();
/**
* Returns length of the byte array, returning 0 if the array is null.
* Useful for calculating sizes.
*
* @param b
* byte array, which can be null
* @return 0 if b is null, otherwise returns length
*/
final public static int len(byte[] b) {
return b == null ? 0 : b.length;
}
/**
* Put bytes at the specified byte array position.
*
* @param tgtBytes
* the byte array
* @param tgtOffset
* position in the array
* @param srcBytes
* array to write out
* @param srcOffset
* source offset
* @param srcLength
* source length
* @return incremented offset
*/
public static int putBytes(byte[] tgtBytes, int tgtOffset, byte[] srcBytes, int srcOffset, int srcLength) {
System.arraycopy(srcBytes, srcOffset, tgtBytes, tgtOffset, srcLength);
return tgtOffset + srcLength;
}
/**
* Write a single byte out to the specified byte array position.
*
* @param bytes
* the byte array
* @param offset
* position in the array
* @param b
* byte to write out
* @return incremented offset
*/
public static int putByte(byte[] bytes, int offset, byte b) {
bytes[offset] = b;
return offset + 1;
}
/**
* Add the whole content of the ByteBuffer to the bytes arrays. The
* ByteBuffer is modified.
*
* @param bytes
* the byte array
* @param offset
* position in the array
* @param buf
* ByteBuffer to write out
* @return incremented offset
*/
public static int putByteBuffer(byte[] bytes, int offset, ByteBuffer buf) {
int len = buf.remaining();
buf.get(bytes, offset, len);
return offset + len;
}
/**
* Returns a new byte array, copied from the given {@code buf}, from the
* index 0 (inclusive) to the limit (exclusive), regardless of the current
* position. The position and the other index parameters are not changed.
*
* @param buf
* a byte buffer
* @return the byte array
* @see #getBytes(ByteBuffer)
*/
public static byte[] toBytes(ByteBuffer buf) {
ByteBuffer dup = buf.duplicate();
dup.position(0);
return readBytes(dup);
}
private static byte[] readBytes(ByteBuffer buf) {
byte[] result = new byte[buf.remaining()];
buf.get(result);
return result;
}
/**
* @param b
* Presumed UTF-8 encoded byte array.
* @return String made from b
*/
public static String toString(final byte[] b) {
if (b == null) {
return null;
}
return toString(b, 0, b.length);
}
/**
* Joins two byte arrays together using a separator.
*
* @param b1
* The first byte array.
* @param sep
* The separator to use.
* @param b2
* The second byte array.
*/
public static String toString(final byte[] b1, String sep, final byte[] b2) {
return toString(b1, 0, b1.length) + sep + toString(b2, 0, b2.length);
}
/**
* This method will convert utf8 encoded bytes into a string. If the given
* byte array is null, this method will return null.
*
* @param b
* Presumed UTF-8 encoded byte array.
* @param off
* offset into array
* @return String made from b or null
*/
public static String toString(final byte[] b, int off) {
if (b == null) {
return null;
}
int len = b.length - off;
if (len <= 0) {
return "";
}
return new String(b, off, len, UTF8_CHARSET);
}
/**
* This method will convert utf8 encoded bytes into a string. If the given
* byte array is null, this method will return null.
*
* @param b
* Presumed UTF-8 encoded byte array.
* @param off
* offset into array
* @param len
* length of utf-8 sequence
* @return String made from b or null
*/
public static String toString(final byte[] b, int off, int len) {
if (b == null) {
return null;
}
if (len == 0) {
return "";
}
return new String(b, off, len, UTF8_CHARSET);
}
/**
* 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);
}
/**
* Converts the given byte buffer to a printable representation, from the
* index 0 (inclusive) to the limit (exclusive), regardless of the current
* position. The position and the other index parameters are not changed.
*
* @param buf
* a byte buffer
* @return a string representation of the buffer's binary contents
* @see #toBytes(ByteBuffer)
* @see #getBytes(ByteBuffer)
*/
public static String toStringBinary(ByteBuffer buf) {
if (buf == null)
return "null";
if (buf.hasArray()) {
return toStringBinary(buf.array(), buf.arrayOffset(), buf.limit());
}
return toStringBinary(toBytes(buf));
}
/**
* Write a printable representation of a byte array. Non-printable
* characters are hex escaped in the format \\x%02X, eg: \x00 \x05 etc
*
* @param b
* array to write out
* @param off
* offset to start at
* @param len
* length to write
* @return string output
*/
public static String toStringBinary(final byte[] b, int off, int len) {
StringBuilder result = new StringBuilder();
// Just in case we are passed a 'len' that is > buffer length...
if (off >= b.length)
return result.toString();
if (off + len > b.length)
len = b.length - off;
for (int i = off; i < off + len; ++i) {
int ch = b[i] & 0xFF;
if ((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z')
|| " `~!@#$%^&*()-_=+[]{}|;:'\",.<>/?".indexOf(ch) >= 0) {
result.append((char) ch);
} else {
result.append(String.format("\\x%02X", ch));
}
}
return result.toString();
}
private static boolean isHexDigit(char c) {
return (c >= 'A' && c <= 'F') || (c >= '0' && c <= '9');
}
/**
* Takes a ASCII digit in the range A-F0-9 and returns the corresponding
* integer/ordinal value.
*
* @param ch
* The hex digit.
* @return The converted hex value as a byte.
*/
public static byte toBinaryFromHex(byte ch) {
if (ch >= 'A' && ch <= 'F')
return (byte) ((byte) 10 + (byte) (ch - 'A'));
// else
return (byte) (ch - '0');
}
public static byte[] toBytesBinary(String in) {
// this may be bigger than we need, but let's be safe.
byte[] b = new byte[in.length()];
int size = 0;
for (int i = 0; i < in.length(); ++i) {
char ch = in.charAt(i);
if (ch == '\\' && in.length() > i + 1 && in.charAt(i + 1) == 'x') {
// ok, take next 2 hex digits.
char hd1 = in.charAt(i + 2);
char hd2 = in.charAt(i + 3);
// they need to be A-F0-9:
if (!isHexDigit(hd1) || !isHexDigit(hd2)) {
// bogus escape code, ignore:
continue;
}
// turn hex ASCII digit -> number
byte d = (byte) ((toBinaryFromHex((byte) hd1) << 4) + toBinaryFromHex((byte) hd2));
b[size++] = d;
i += 3; // skip 3
} else {
b[size++] = (byte) ch;
}
}
// resize:
byte[] b2 = new byte[size];
System.arraycopy(b, 0, b2, 0, size);
return b2;
}
/**
* Converts a string to a UTF-8 byte array.
*
* @param s
* string
* @return the byte array
*/
public static byte[] toBytes(String s) {
return s.getBytes(UTF8_CHARSET);
}
/**
* 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);
}
if (UNSAFE_UNALIGNED) {
return toLongUnsafe(bytes, offset);
} else {
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);
}
/**
* 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) {
int ti = toInt(bytes, offset, SIZEOF_INT);
return Float.intBitsToFloat(ti);
}
/**
* @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 toBytes(Float.floatToRawIntBits(f));
}
/**
* @param bytes
* byte array
* @return Return double made from passed bytes.
*/
public static double toDouble(final byte[] bytes) {
return toDouble(bytes, 0);
}
/**
* @param bytes
* byte array
* @param offset
* offset where double is
* @return Return double made from passed bytes.
*/
public static double toDouble(final byte[] bytes, final int offset) {
return Double.longBitsToDouble(toLong(bytes, offset, SIZEOF_LONG));
}
/**
* 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 toBytes(Double.doubleToRawLongBits(d));
}
/**
* Convert an int value to a byte array. Big-endian. Same as what
* DataOutputStream.writeInt does.
*
* @param val
* value
* @return the byte array
*/
public static byte[] toBytes(int val) {
byte[] b = new byte[4];
for (int i = 3; i > 0; i--) {
b[i] = (byte) val;
val >>>= 8;
}
b[0] = (byte) val;
return b;
}
/**
* Converts a byte array to an int value
*
* @param bytes
* byte array
* @return the int value
*/
public static int toInt(byte[] bytes) {
return toInt(bytes, 0, SIZEOF_INT);
}
/**
* Converts a byte array to an int value
*
* @param bytes
* byte array
* @param offset
* offset into array
* @return the int value
*/
public static int toInt(byte[] bytes, int offset) {
return toInt(bytes, offset, SIZEOF_INT);
}
/**
* Converts a byte array to an int value
*
* @param bytes
* byte array
* @param offset
* offset into array
* @param length
* length of int (has to be {@link #SIZEOF_INT})
* @return the int value
* @throws IllegalArgumentException
* if length is not {@link #SIZEOF_INT} or if there's not enough
* room in the array at the offset indicated.
*/
public static int toInt(byte[] bytes, int offset, final int length) {
if (length != SIZEOF_INT || offset + length > bytes.length) {
throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_INT);
}
if (UNSAFE_UNALIGNED) {
return toIntUnsafe(bytes, offset);
} else {
int n = 0;
for (int i = offset; i < (offset + length); i++) {
n <<= 8;
n ^= bytes[i] & 0xFF;
}
return n;
}
}
/**
* Converts a byte array to an int value (Unsafe version)
*
* @param bytes
* byte array
* @param offset
* offset into array
* @return the int value
*/
public static int toIntUnsafe(byte[] bytes, int offset) {
if (UnsafeComparer.littleEndian) {
return Integer.reverseBytes(
UnsafeComparer.theUnsafe.getInt(bytes, (long) offset + UnsafeComparer.BYTE_ARRAY_BASE_OFFSET));
} else {
return UnsafeComparer.theUnsafe.getInt(bytes, (long) offset + UnsafeComparer.BYTE_ARRAY_BASE_OFFSET);
}
}
/**
* Converts a byte array to an short value (Unsafe version)
*
* @param bytes
* byte array
* @param offset
* offset into array
* @return the short value
*/
public static short toShortUnsafe(byte[] bytes, int offset) {
if (UnsafeComparer.littleEndian) {
return Short.reverseBytes(
UnsafeComparer.theUnsafe.getShort(bytes, (long) offset + UnsafeComparer.BYTE_ARRAY_BASE_OFFSET));
} else {
return UnsafeComparer.theUnsafe.getShort(bytes, (long) offset + UnsafeComparer.BYTE_ARRAY_BASE_OFFSET);
}
}
/**
* Converts a byte array to an long value (Unsafe version)
*
* @param bytes
* byte array
* @param offset
* offset into array
* @return the long value
*/
public static long toLongUnsafe(byte[] bytes, int offset) {
if (UnsafeComparer.littleEndian) {
return Long.reverseBytes(
UnsafeComparer.theUnsafe.getLong(bytes, (long) offset + UnsafeComparer.BYTE_ARRAY_BASE_OFFSET));
} else {
return UnsafeComparer.theUnsafe.getLong(bytes, (long) offset + UnsafeComparer.BYTE_ARRAY_BASE_OFFSET);
}
}
/**
* Converts a byte array to an int value
*
* @param bytes
* byte array
* @param offset
* offset into array
* @param length
* how many bytes should be considered for creating int
* @return the int value
* @throws IllegalArgumentException
* if there's not enough room in the array at the offset
* indicated.
*/
public static int readAsInt(byte[] bytes, int offset, final int length) {
if (offset + length > bytes.length) {
throw new IllegalArgumentException("offset (" + offset + ") + length (" + length + ") exceed the"
+ " capacity of the array: " + bytes.length);
}
int n = 0;
for (int i = offset; i < (offset + length); i++) {
n <<= 8;
n ^= bytes[i] & 0xFF;
}
return n;
}
/**
* Put an int value out to the specified byte array position.
*
* @param bytes
* the byte array
* @param offset
* position in the array
* @param val
* int to write out
* @return incremented offset
* @throws IllegalArgumentException
* if the byte array given doesn't have enough room at the
* offset specified.
*/
public static int putInt(byte[] bytes, int offset, int val) {
if (bytes.length - offset < SIZEOF_INT) {
throw new IllegalArgumentException(
"Not enough room to put an int at" + " offset " + offset + " in a " + bytes.length + " byte array");
}
if (UNSAFE_UNALIGNED) {
return putIntUnsafe(bytes, offset, val);
} else {
for (int i = offset + 3; i > offset; i--) {
bytes[i] = (byte) val;
val >>>= 8;
}
bytes[offset] = (byte) val;
return offset + SIZEOF_INT;
}
}
/**
* Put an int value out to the specified byte array position (Unsafe).
*
* @param bytes
* the byte array
* @param offset
* position in the array
* @param val
* int to write out
* @return incremented offset
*/
public static int putIntUnsafe(byte[] bytes, int offset, int val) {
if (UnsafeComparer.littleEndian) {
val = Integer.reverseBytes(val);
}
UnsafeComparer.theUnsafe.putInt(bytes, (long) offset + UnsafeComparer.BYTE_ARRAY_BASE_OFFSET, 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);
}
if (UNSAFE_UNALIGNED) {
return toShortUnsafe(bytes, offset);
} else {
short n = 0;
n ^= bytes[offset] & 0xFF;
n <<= 8;
n ^= bytes[offset + 1] & 0xFF;
return n;
}
}
/**
* Returns a new byte array, copied from the given {@code buf}, from the
* position (inclusive) to the limit (exclusive). The position and the other
* index parameters are not changed.
*
* @param buf
* a byte buffer
* @return the byte array
* @see #toBytes(ByteBuffer)
*/
public static byte[] getBytes(ByteBuffer buf) {
return readBytes(buf.duplicate());
}
/**
* Put a short value out to the specified byte array position.
*
* @param bytes
* the byte array
* @param offset
* position in the array
* @param val
* short to write out
* @return incremented offset
* @throws IllegalArgumentException
* if the byte array given doesn't have enough room at the
* offset specified.
*/
public static int putShort(byte[] bytes, int offset, short val) {
if (bytes.length - offset < SIZEOF_SHORT) {
throw new IllegalArgumentException("Not enough room to put a short at" + " offset " + offset + " in a "
+ bytes.length + " byte array");
}
if (UNSAFE_UNALIGNED) {
return putShortUnsafe(bytes, offset, val);
} else {
bytes[offset + 1] = (byte) val;
val >>= 8;
bytes[offset] = (byte) val;
return offset + SIZEOF_SHORT;
}
}
/**
* Put a short value out to the specified byte array position (Unsafe).
*
* @param bytes
* the byte array
* @param offset
* position in the array
* @param val
* short to write out
* @return incremented offset
*/
public static int putShortUnsafe(byte[] bytes, int offset, short val) {
if (UnsafeComparer.littleEndian) {
val = Short.reverseBytes(val);
}
UnsafeComparer.theUnsafe.putShort(bytes, (long) offset + UnsafeComparer.BYTE_ARRAY_BASE_OFFSET, val);
return offset + SIZEOF_SHORT;
}
/**
* Put an int value as short out to the specified byte array position. Only
* the lower 2 bytes of the short will be put into the array. The caller of
* the API need to make sure they will not loose the value by doing so. This
* is useful to store an unsigned short which is represented as int in other
* parts.
*
* @param bytes
* the byte array
* @param offset
* position in the array
* @param val
* value to write out
* @return incremented offset
* @throws IllegalArgumentException
* if the byte array given doesn't have enough room at the
* offset specified.
*/
public static int putAsShort(byte[] bytes, int offset, int val) {
if (bytes.length - offset < SIZEOF_SHORT) {
throw new IllegalArgumentException("Not enough room to put a short at" + " offset " + offset + " in a "
+ bytes.length + " byte array");
}
bytes[offset + 1] = (byte) val;
val >>= 8;
bytes[offset] = (byte) val;
return offset + SIZEOF_SHORT;
}
/**
* Convert a BigDecimal value to a byte array
*
* @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);
}
/**
* @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 {
int compareTo(T buffer1, int offset1, int length1, T buffer2, int offset2, int length2);
}
static Comparer lexicographicalComparerJavaImpl() {
return LexicographicalComparerHolder.PureJavaComparer.INSTANCE;
}
/**
* Provides a lexicographical comparer implementation; either a Java
* implementation or a faster implementation based on {@link Unsafe}.
*
*
* Uses reflection to gracefully fall back to the Java implementation if
* {@code Unsafe} isn't available.
*/
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;
}
}
enum UnsafeComparer implements Comparer {
INSTANCE;
static final Unsafe theUnsafe;
/** The offset to the first element in a byte array. */
static final int BYTE_ARRAY_BASE_OFFSET;
static {
if (UNSAFE_UNALIGNED) {
theUnsafe = UnsafeAccess.theUnsafe;
} else {
// It doesn't matter what we throw;
// it's swallowed in getBestComparer().
throw new Error();
}
BYTE_ARRAY_BASE_OFFSET = theUnsafe.arrayBaseOffset(byte[].class);
// sanity check - this should never fail
if (theUnsafe.arrayIndexScale(byte[].class) != 1) {
throw new AssertionError();
}
}
static final boolean littleEndian = ByteOrder.nativeOrder().equals(ByteOrder.LITTLE_ENDIAN);
/**
* Returns true if x1 is less than x2, when both values are treated
* as unsigned long. Both values are passed as is read by Unsafe.
* When platform is Little Endian, have to convert to corresponding
* Big Endian value and then do compare. We do all writes in Big
* Endian format.
*/
static boolean lessThanUnsignedLong(long x1, long x2) {
if (littleEndian) {
x1 = Long.reverseBytes(x1);
x2 = Long.reverseBytes(x2);
}
return (x1 + Long.MIN_VALUE) < (x2 + Long.MIN_VALUE);
}
/**
* Returns true if x1 is less than x2, when both values are treated
* as unsigned int. Both values are passed as is read by Unsafe.
* When platform is Little Endian, have to convert to corresponding
* Big Endian value and then do compare. We do all writes in Big
* Endian format.
*/
static boolean lessThanUnsignedInt(int x1, int x2) {
if (littleEndian) {
x1 = Integer.reverseBytes(x1);
x2 = Integer.reverseBytes(x2);
}
return (x1 & 0xffffffffL) < (x2 & 0xffffffffL);
}
/**
* Returns true if x1 is less than x2, when both values are treated
* as unsigned short. Both values are passed as is read by Unsafe.
* When platform is Little Endian, have to convert to corresponding
* Big Endian value and then do compare. We do all writes in Big
* Endian format.
*/
static boolean lessThanUnsignedShort(short x1, short x2) {
if (littleEndian) {
x1 = Short.reverseBytes(x1);
x2 = Short.reverseBytes(x2);
}
return (x1 & 0xffff) < (x2 & 0xffff);
}
/**
* Checks if Unsafe is available
*
* @return true, if available, false - otherwise
*/
public static boolean isAvailable() {
return theUnsafe != null;
}
/**
* Lexicographically compare two arrays.
*
* @param buffer1
* left operand
* @param buffer2
* right operand
* @param offset1
* Where to start comparing in the left buffer
* @param offset2
* Where to start comparing in the right buffer
* @param length1
* How much to compare from the left buffer
* @param length2
* How much to compare from the right buffer
* @return 0 if equal, < 0 if left is less than right, etc.
*/
@Override
public int compareTo(byte[] buffer1, int offset1, int length1, byte[] buffer2, int offset2, int length2) {
// Short circuit equal case
if (buffer1 == buffer2 && offset1 == offset2 && length1 == length2) {
return 0;
}
final int minLength = Math.min(length1, length2);
final int minWords = minLength / SIZEOF_LONG;
final long offset1Adj = offset1 + BYTE_ARRAY_BASE_OFFSET;
final long offset2Adj = offset2 + BYTE_ARRAY_BASE_OFFSET;
/*
* Compare 8 bytes at a time. Benchmarking shows comparing 8
* bytes at a time is no slower than comparing 4 bytes at a time
* even on 32-bit. On the other hand, it is substantially faster
* on 64-bit.
*/
// This is the end offset of long parts.
int j = minWords << 3; // Same as minWords * SIZEOF_LONG
for (int i = 0; i < j; i += SIZEOF_LONG) {
long lw = theUnsafe.getLong(buffer1, offset1Adj + (long) i);
long rw = theUnsafe.getLong(buffer2, offset2Adj + (long) i);
long diff = lw ^ rw;
if (diff != 0) {
return lessThanUnsignedLong(lw, rw) ? -1 : 1;
}
}
int offset = j;
if (minLength - offset >= SIZEOF_INT) {
int il = theUnsafe.getInt(buffer1, offset1Adj + offset);
int ir = theUnsafe.getInt(buffer2, offset2Adj + offset);
if (il != ir) {
return lessThanUnsignedInt(il, ir) ? -1 : 1;
}
offset += SIZEOF_INT;
}
if (minLength - offset >= SIZEOF_SHORT) {
short sl = theUnsafe.getShort(buffer1, offset1Adj + offset);
short sr = theUnsafe.getShort(buffer2, offset2Adj + offset);
if (sl != sr) {
return lessThanUnsignedShort(sl, sr) ? -1 : 1;
}
offset += SIZEOF_SHORT;
}
if (minLength - offset == 1) {
int a = (buffer1[(int) (offset1 + offset)] & 0xff);
int b = (buffer2[(int) (offset2 + offset)] & 0xff);
if (a != b) {
return a - b;
}
}
return length1 - length2;
}
}
}
/**
* @param left
* left operand
* @param right
* right operand
* @return True if equal
*/
public static boolean equals(final byte[] left, final byte[] right) {
// Could use Arrays.equals?
// noinspection SimplifiableConditionalExpression
if (left == right)
return true;
if (left == null || right == null)
return false;
if (left.length != right.length)
return false;
if (left.length == 0)
return true;
// Since we're often comparing adjacent sorted data,
// it's usual to have equal arrays except for the very last byte
// so check that first
if (left[left.length - 1] != right[right.length - 1])
return false;
return compareTo(left, right) == 0;
}
public static boolean equals(final byte[] left, int leftOffset, int leftLen, final byte[] right, int rightOffset,
int rightLen) {
// short circuit case
if (left == right && leftOffset == rightOffset && leftLen == rightLen) {
return true;
}
// different lengths fast check
if (leftLen != rightLen) {
return false;
}
if (leftLen == 0) {
return true;
}
// Since we're often comparing adjacent sorted data,
// it's usual to have equal arrays except for the very last byte
// so check that first
if (left[leftOffset + leftLen - 1] != right[rightOffset + rightLen - 1])
return false;
return LexicographicalComparerHolder.BEST_COMPARER.compareTo(left, leftOffset, leftLen, right, rightOffset,
rightLen) == 0;
}
/**
* @param a
* left operand
* @param buf
* right operand
* @return True if equal
*/
public static boolean equals(byte[] a, ByteBuffer buf) {
if (a == null)
return buf == null;
if (buf == null)
return false;
if (a.length != buf.remaining())
return false;
// Thou shalt not modify the original byte buffer in what should be read
// only operations.
ByteBuffer b = buf.duplicate();
for (byte anA : a) {
if (anA != b.get()) {
return false;
}
}
return true;
}
/**
* Return true if the byte array on the right is a prefix of the byte array
* on the left.
*/
public static boolean startsWith(byte[] bytes, byte[] prefix) {
return bytes != null && prefix != null && bytes.length >= prefix.length
&& LexicographicalComparerHolder.BEST_COMPARER.compareTo(bytes, 0, prefix.length, prefix, 0,
prefix.length) == 0;
}
/**
* @param a
* lower half
* @param b
* upper half
* @return New array that has a in lower half and b in upper half.
*/
public static byte[] add(final byte[] a, final byte[] b) {
return add(a, b, EMPTY_BYTE_ARRAY);
}
/**
* @param a
* first third
* @param b
* second third
* @param c
* third third
* @return New array made from a, b and c
*/
public static byte[] add(final byte[] a, final byte[] b, final byte[] c) {
byte[] result = new byte[a.length + b.length + c.length];
System.arraycopy(a, 0, result, 0, a.length);
System.arraycopy(b, 0, result, a.length, b.length);
System.arraycopy(c, 0, result, a.length + b.length, c.length);
return result;
}
/**
* @param arrays
* all the arrays to concatenate together.
* @return New array made from the concatenation of the given arrays.
*/
public static byte[] add(final byte[][] arrays) {
int length = 0;
for (int i = 0; i < arrays.length; i++) {
length += arrays[i].length;
}
byte[] result = new byte[length];
int index = 0;
for (int i = 0; i < arrays.length; i++) {
System.arraycopy(arrays[i], 0, result, index, arrays[i].length);
index += arrays[i].length;
}
return result;
}
/**
* @param a
* array
* @param length
* amount of bytes to grab
* @return First length bytes from a
*/
public static byte[] head(final byte[] a, final int length) {
if (a.length < length) {
return null;
}
byte[] result = new byte[length];
System.arraycopy(a, 0, result, 0, length);
return result;
}
/**
* @param a
* array
* @param length
* amount of bytes to snarf
* @return Last length bytes from a
*/
public static byte[] tail(final byte[] a, final int length) {
if (a.length < length) {
return null;
}
byte[] result = new byte[length];
System.arraycopy(a, a.length - length, result, 0, length);
return result;
}
/**
* @param a
* array
* @param length
* new array size
* @return Value in a plus length prepended 0
* bytes
*/
public static byte[] padHead(final byte[] a, final int length) {
byte[] padding = new byte[length];
for (int i = 0; i < length; i++) {
padding[i] = 0;
}
return add(padding, a);
}
/**
* @param a
* array
* @param length
* new array size
* @return Value in a plus length appended 0 bytes
*/
public static byte[] padTail(final byte[] a, final int length) {
byte[] padding = new byte[length];
for (int i = 0; i < length; i++) {
padding[i] = 0;
}
return add(a, padding);
}
/**
* Split passed range. Expensive operation relatively. Uses BigInteger math.
* Useful splitting ranges for MapReduce jobs.
*
* @param a
* Beginning of range
* @param b
* End of range
* @param num
* Number of times to split range. Pass 1 if you want to split
* the range in two; i.e. one split.
* @return Array of dividing values
*/
public static byte[][] split(final byte[] a, final byte[] b, final int num) {
return split(a, b, false, num);
}
/**
* Split passed range. Expensive operation relatively. Uses BigInteger math.
* Useful splitting ranges for MapReduce jobs.
*
* @param a
* Beginning of range
* @param b
* End of range
* @param inclusive
* Whether the end of range is prefix-inclusive or is considered
* an exclusive boundary. Automatic splits are generally
* exclusive and manual splits with an explicit range utilize an
* inclusive end of range.
* @param num
* Number of times to split range. Pass 1 if you want to split
* the range in two; i.e. one split.
* @return Array of dividing values
*/
public static byte[][] split(final byte[] a, final byte[] b, boolean inclusive, final int num) {
byte[][] ret = new byte[num + 2][];
int i = 0;
Iterable iter = iterateOnSplits(a, b, inclusive, num);
if (iter == null)
return null;
for (byte[] elem : iter) {
ret[i++] = elem;
}
return ret;
}
/**
* Iterate over keys within the passed range, splitting at an [a,b)
* boundary.
*/
public static Iterable iterateOnSplits(final byte[] a, final byte[] b, final int num) {
return iterateOnSplits(a, b, false, num);
}
/**
* Iterate over keys within the passed range.
*/
public static Iterable iterateOnSplits(final byte[] a, final byte[] b, boolean inclusive, final int num) {
byte[] aPadded;
byte[] bPadded;
if (a.length < b.length) {
aPadded = padTail(a, b.length - a.length);
bPadded = b;
} else if (b.length < a.length) {
aPadded = a;
bPadded = padTail(b, a.length - b.length);
} else {
aPadded = a;
bPadded = b;
}
if (compareTo(aPadded, bPadded) >= 0) {
throw new IllegalArgumentException("b <= a");
}
if (num <= 0) {
throw new IllegalArgumentException("num cannot be <= 0");
}
byte[] prependHeader = { 1, 0 };
final BigInteger startBI = new BigInteger(add(prependHeader, aPadded));
final BigInteger stopBI = new BigInteger(add(prependHeader, bPadded));
BigInteger diffBI = stopBI.subtract(startBI);
if (inclusive) {
diffBI = diffBI.add(BigInteger.ONE);
}
final BigInteger splitsBI = BigInteger.valueOf(num + 1);
// when diffBI < splitBI, use an additional byte to increase diffBI
if (diffBI.compareTo(splitsBI) < 0) {
byte[] aPaddedAdditional = new byte[aPadded.length + 1];
byte[] bPaddedAdditional = new byte[bPadded.length + 1];
for (int i = 0; i < aPadded.length; i++) {
aPaddedAdditional[i] = aPadded[i];
}
for (int j = 0; j < bPadded.length; j++) {
bPaddedAdditional[j] = bPadded[j];
}
aPaddedAdditional[aPadded.length] = 0;
bPaddedAdditional[bPadded.length] = 0;
return iterateOnSplits(aPaddedAdditional, bPaddedAdditional, inclusive, num);
}
final BigInteger intervalBI;
try {
intervalBI = diffBI.divide(splitsBI);
} catch (Exception e) {
// LOG.error("Exception caught during division", e);
logger.log(Level.SEVERE, "Exception caught during division", e);
return null;
}
final Iterator iterator = new Iterator() {
private int i = -1;
@Override
public boolean hasNext() {
return i < num + 1;
}
@Override
public byte[] next() {
i++;
if (i == 0)
return a;
if (i == num + 1)
return b;
BigInteger curBI = startBI.add(intervalBI.multiply(BigInteger.valueOf(i)));
byte[] padded = curBI.toByteArray();
if (padded[1] == 0)
padded = tail(padded, padded.length - 2);
else
padded = tail(padded, padded.length - 1);
return padded;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
return new Iterable() {
@Override
public Iterator iterator() {
return iterator;
}
};
}
/**
* @param bytes
* array to hash
* @param offset
* offset to start from
* @param length
* length to hash
*/
public static int hashCode(byte[] bytes, int offset, int length) {
int hash = 1;
for (int i = offset; i < offset + length; i++)
hash = (31 * hash) + (int) bytes[i];
return hash;
}
/**
* @param t
* operands
* @return Array of byte arrays made from passed array of Text
*/
public static byte[][] toByteArrays(final String[] t) {
byte[][] result = new byte[t.length][];
for (int i = 0; i < t.length; i++) {
result[i] = toBytes(t[i]);
}
return result;
}
/**
* @param t
* operands
* @return Array of binary byte arrays made from passed array of binary
* strings
*/
public static byte[][] toBinaryByteArrays(final String[] t) {
byte[][] result = new byte[t.length][];
for (int i = 0; i < t.length; i++) {
result[i] = toBytesBinary(t[i]);
}
return result;
}
/**
* @param column
* operand
* @return A byte array of a byte array where first and only entry is
* column
*/
public static byte[][] toByteArrays(final String column) {
return toByteArrays(toBytes(column));
}
/**
* @param column
* operand
* @return A byte array of a byte array where first and only entry is
* column
*/
public static byte[][] toByteArrays(final byte[] column) {
byte[][] result = new byte[1][];
result[0] = column;
return result;
}
}
class UnsafeAvailChecker {
static final Logger logger = Logger.getLogger(UnsafeAvailChecker.class.getName());
private static final String CLASS_NAME = "sun.misc.Unsafe";
private static boolean avail = false;
private static boolean unaligned = false;
static {
avail = AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Boolean run() {
try {
Class> clazz = Class.forName(CLASS_NAME);
Field f = clazz.getDeclaredField("theUnsafe");
f.setAccessible(true);
return f.get(null) != null;
} catch (Throwable e) {
logger.log(Level.WARNING, "sun.misc.Unsafe is not available/accessible", e);
}
return false;
}
});
// When Unsafe itself is not available/accessible consider unaligned as
// false.
if (avail) {
try {
// Using java.nio.Bits#unaligned() to check for unaligned-access
// capability
Class> clazz = Class.forName("java.nio.Bits");
Method m = clazz.getDeclaredMethod("unaligned");
m.setAccessible(true);
unaligned = (Boolean) m.invoke(null);
} catch (Exception e) {
logger.log(Level.WARNING, "java.nio.Bits#unaligned() check failed."
+ "Unsafe based read/write of primitive types won't be used", e);
}
}
}
/**
* @return true when running JVM is having sun's Unsafe package available in
* it and underlying system having unaligned-access capability.
*/
public static boolean unaligned() {
return unaligned;
}
}
@SuppressWarnings("restriction")
final class UnsafeAccess {
static final Logger logger = Logger.getLogger(UnsafeAccess.class.getName());
public static final Unsafe theUnsafe;
static {
theUnsafe = (Unsafe) AccessController.doPrivileged(new PrivilegedAction
転載先:https://www.cnblogs.com/moonciki/p/8145834.html