Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.kylin.common.util; import static com.google.common.base.Preconditions.checkArgument; import static com.google.common.base.Preconditions.checkNotNull; import static com.google.common.base.Preconditions.checkPositionIndex; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import java.lang.reflect.Field; 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.security.SecureRandom; import java.util.Arrays; import java.util.Iterator; import java.util.List; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import sun.misc.Unsafe; /** * Utility class that handles byte arrays, conversions to/from other types, * comparisons, hash code generation, manufacturing keys for HashMaps or * HashSets, etc. * * Copied from org.apache.hadoop.hbase.util.Bytes */ public class Bytes { //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 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; /** * Estimate of size cost to pay beyond payload in jvm for instance of byte []. * Estimate based on study of jhat and jprofiler numbers. */ // JHat says BU is 56 bytes. // SizeOf which uses java.lang.instrument says 24 bytes. (3 longs?) public static final int ESTIMATED_HEAP_TAX = 16; /** * 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 <code>b</code> */ 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 * @param len length of utf-8 sequence * @return String made from <code>b</code> 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)) & 0xff); 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 <code>b</code> 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 (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.isAvailable()) { 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); } /** * 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"); } if (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.isAvailable()) { return putLongUnsafe(bytes, offset, val); } else { for (int i = offset + 7; i > offset; i--) { bytes[i] = (byte) val; val >>>= 8; } bytes[offset] = (byte) val; return offset + SIZEOF_LONG; } } /** * Put a long value out to the specified byte array position (Unsafe). * * @param bytes the byte array * @param offset position in the array * @param val long to write out * @return incremented offset */ public static int putLongUnsafe(byte[] bytes, int offset, long val) { if (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.littleEndian) { val = Long.reverseBytes(val); } org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.theUnsafe.putLong(bytes, (long) offset + org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.BYTE_ARRAY_BASE_OFFSET, 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)); } /** * @param bytes byte array * @param offset offset to write to * @param f float value * @return New offset in <code>bytes</code> */ public static int putFloat(byte[] bytes, int offset, float f) { return putInt(bytes, offset, Float.floatToRawIntBits(f)); } /** * @param f float value * @return the float represented as byte [] */ public static byte[] toBytes(final float f) { // Encode it as int return Bytes.toBytes(Float.floatToRawIntBits(f)); } /** * @param bytes byte array * @return Return double made from passed bytes. */ public static double toDouble(final byte[] bytes) { return toDouble(bytes, 0); } /** * @param bytes byte array * @param offset offset where double is * @return Return double made from passed bytes. */ public static double toDouble(final byte[] bytes, final int offset) { return Double.longBitsToDouble(toLong(bytes, offset, SIZEOF_LONG)); } /** * @param bytes byte array * @param offset offset to write to * @param d value * @return New offset into array <code>bytes</code> */ public static int putDouble(byte[] bytes, int offset, double d) { return putLong(bytes, offset, Double.doubleToLongBits(d)); } /** * Serialize a double as the IEEE 754 double format output. The resultant * array will be 8 bytes long. * * @param d value * @return the double represented as byte [] */ public static byte[] toBytes(final double d) { // Encode it as a long return Bytes.toBytes(Double.doubleToRawLongBits(d)); } /** * Convert an int value to a byte array. Big-endian. Same as what DataOutputStream.writeInt * does. * * @param val value * @return the byte array */ public static byte[] toBytes(int val) { byte[] b = new byte[4]; for (int i = 3; i > 0; i--) { b[i] = (byte) val; val >>>= 8; } b[0] = (byte) val; return b; } /** * Converts a byte array to an int value * * @param bytes byte array * @return the int value */ public static int toInt(byte[] bytes) { return toInt(bytes, 0, SIZEOF_INT); } /** * Converts a byte array to an int value * * @param bytes byte array * @param offset offset into array * @return the int value */ public static int toInt(byte[] bytes, int offset) { return toInt(bytes, offset, SIZEOF_INT); } /** * Converts a byte array to an int value * * @param bytes byte array * @param offset offset into array * @param length length of int (has to be {@link #SIZEOF_INT}) * @return the int value * @throws IllegalArgumentException if length is not {@link #SIZEOF_INT} or * if there's not enough room in the array at the offset indicated. */ public static int toInt(byte[] bytes, int offset, final int length) { if (length != SIZEOF_INT || offset + length > bytes.length) { throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_INT); } if (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.isAvailable()) { 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 (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.littleEndian) { return Integer.reverseBytes( org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.theUnsafe .getInt(bytes, (long) offset + org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.BYTE_ARRAY_BASE_OFFSET)); } else { return org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.theUnsafe .getInt(bytes, (long) offset + org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.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 (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.littleEndian) { return Short.reverseBytes( org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.theUnsafe .getShort(bytes, (long) offset + org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.BYTE_ARRAY_BASE_OFFSET)); } else { return org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.theUnsafe .getShort(bytes, (long) offset + org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.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 (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.littleEndian) { return Long.reverseBytes( org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.theUnsafe .getLong(bytes, (long) offset + org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.BYTE_ARRAY_BASE_OFFSET)); } else { return org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.theUnsafe .getLong(bytes, (long) offset + org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.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 (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.isAvailable()) { 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 (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.littleEndian) { val = Integer.reverseBytes(val); } org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.theUnsafe.putInt(bytes, (long) offset + org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.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 (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.isAvailable()) { 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 (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.isAvailable()) { 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 (org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.littleEndian) { val = Short.reverseBytes(val); } org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.UnsafeComparer.theUnsafe.putShort(bytes, (long) offset + org.apache.kylin.common.util.Bytes.LexicographicalComparerHolder.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<T> { int compareTo(T buffer1, int offset1, int length1, T buffer2, int offset2, int length2); } static Comparer<byte[]> lexicographicalComparerJavaImpl() { return LexicographicalComparerHolder.PureJavaComparer.INSTANCE; } /** * Provides a lexicographical comparer implementation; either a Java * implementation or a faster implementation based on {@link sun.misc.Unsafe}. * <p/> * <p>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<byte[]> BEST_COMPARER = getBestComparer(); /** * Returns the Unsafe-using Comparer, or falls back to the pure-Java * implementation if unable to do so. */ static Comparer<byte[]> getBestComparer() { try { Class<?> theClass = Class.forName(UNSAFE_COMPARER_NAME); // yes, UnsafeComparer does implement Comparer<byte[]> @SuppressWarnings("unchecked") Comparer<byte[]> comparer = (Comparer<byte[]>) theClass.getEnumConstants()[0]; return comparer; } catch (Throwable t) { // ensure we really catch *everything* return lexicographicalComparerJavaImpl(); } } enum PureJavaComparer implements Comparer<byte[]> { 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<byte[]> { INSTANCE; static final Unsafe theUnsafe; /** * The offset to the first element in a byte array. */ static final int BYTE_ARRAY_BASE_OFFSET; static { theUnsafe = (Unsafe) AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { try { Field f = Unsafe.class.getDeclaredField("theUnsafe"); f.setAccessible(true); return f.get(null); } catch (NoSuchFieldException e) { // It doesn't matter what we throw; // it's swallowed in getBestComparer(). throw new Error(); } catch (IllegalAccessException e) { 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. */ static boolean lessThanUnsignedLong(long x1, long 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. */ static boolean lessThanUnsignedInt(int x1, int x2) { return (x1 & 0xffffffffL) < (x2 & 0xffffffffL); } /** * Returns true if x1 is less than x2, when both values are treated as * unsigned short. */ static boolean lessThanUnsignedShort(short x1, short 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 + (long) BYTE_ARRAY_BASE_OFFSET; final long offset2Adj = offset2 + (long) 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. */ for (int i = 0; i < minWords * SIZEOF_LONG; i += SIZEOF_LONG) { long lw = theUnsafe.getLong(buffer1, offset1Adj + (long) i); long rw = theUnsafe.getLong(buffer2, offset2Adj + (long) i); long diff = lw ^ rw; if (littleEndian) { lw = Long.reverseBytes(lw); rw = Long.reverseBytes(rw); } if (diff != 0) { return lessThanUnsignedLong(lw, rw) ? -1 : 1; } } int offset = minWords * SIZEOF_LONG; if (minLength - offset >= SIZEOF_INT) { int il = theUnsafe.getInt(buffer1, offset1Adj + offset); int ir = theUnsafe.getInt(buffer2, offset2Adj + offset); if (littleEndian) { il = Integer.reverseBytes(il); ir = Integer.reverseBytes(ir); } 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 (littleEndian) { sl = Short.reverseBytes(sl); sr = Short.reverseBytes(sr); } 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 b bytes to hash * @return Runs {@link org.apache.hadoop.io.WritableComparator#hashBytes(byte[], int)} on the * passed in array. This method is what {@link org.apache.hadoop.io.Text} and * {@link org.apache.hadoop.hbase.io.ImmutableBytesWritable} use calculating hash code. */ public static int hashCode(final byte[] b) { return hashCode(b, b.length); } /** * @param b value * @param length length of the value * @return Runs {@link org.apache.hadoop.io.WritableComparator#hashBytes(byte[], int)} on the * passed in array. This method is what {@link org.apache.hadoop.io.Text} and * {@link org.apache.hadoop.hbase.io.ImmutableBytesWritable} use calculating hash code. */ public static int hashCode(final byte[] b, final int length) { return hashBytes(b, 0, 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) + (int) bytes[i]; return hash; } /** * @param b bytes to hash * @return A hash of <code>b</code> as an Integer that can be used as key in * Maps. */ public static Integer mapKey(final byte[] b) { return hashCode(b); } /** * @param b bytes to hash * @param length length to hash * @return A hash of <code>b</code> as an Integer that can be used as key in * Maps. */ public static Integer mapKey(final byte[] b, final int length) { return hashCode(b, length); } /** * @param a lower half * @param b upper half * @return New array that has a in lower half and b in upper half. */ public static byte[] add(final byte[] a, final byte[] b) { return add(a, b, EMPTY_BYTE_ARRAY); } /** * @param a first third * @param b second third * @param c third third * @return New array made from a, b and c */ public static byte[] add(final byte[] a, final byte[] b, final byte[] c) { byte[] result = new byte[a.length + b.length + c.length]; System.arraycopy(a, 0, result, 0, a.length); System.arraycopy(b, 0, result, a.length, b.length); System.arraycopy(c, 0, result, a.length + b.length, c.length); return result; } /** * @param a array * @param length amount of bytes to grab * @return First <code>length</code> bytes from <code>a</code> */ 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 <code>length</code> bytes from <code>a</code> */ 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 <code>a</code> plus <code>length</code> 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 <code>a</code> plus <code>length</code> 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<byte[]> 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<byte[]> 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<byte[]> 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 + 1L); if (diffBI.compareTo(splitsBI) < 0) { return null; } final BigInteger intervalBI; try { intervalBI = diffBI.divide(splitsBI); } catch (Exception e) { LOG.error("Exception caught during division", e); return null; } final Iterator<byte[]> iterator = new Iterator<byte[]>() { 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<byte[]>() { @Override public Iterator<byte[]> 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] = Bytes.toBytes(t[i]); } return result; } /** * @param column operand * @return A byte array of a byte array where first and only entry is * <code>column</code> */ 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 * <code>column</code> */ 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); } /** * Reads a fixed-size field and interprets it as a string padded with zeros. */ public static String readStringFixedSize(final DataInput in, int size) throws IOException { byte[] b = new byte[size]; in.readFully(b); int n = b.length; while (n > 0 && b[n - 1] == 0) --n; return toString(b, 0, n); } /** * Copy the byte array given in parameter and return an instance * of a new byte array with the same length and the same content. * * @param bytes the byte array to duplicate * @return a copy of the given byte array */ public static byte[] copy(byte[] bytes) { if (bytes == null) return null; byte[] result = new byte[bytes.length]; System.arraycopy(bytes, 0, result, 0, bytes.length); return result; } /** * Copy the byte array given in parameter and return an instance * of a new byte array with the same length and the same content. * * @param bytes the byte array to copy from * @param offset * @param length * @return a copy of the given designated byte array */ public static byte[] copy(byte[] bytes, final int offset, final int length) { if (bytes == null) return null; byte[] result = new byte[length]; System.arraycopy(bytes, offset, result, 0, length); return result; } /** * Search sorted array "a" for byte "key". I can't remember if I wrote this or copied it from * somewhere. (mcorgan) * * @param a Array to search. Entries must be sorted and unique. * @param fromIndex First index inclusive of "a" to include in the search. * @param toIndex Last index exclusive of "a" to include in the search. * @param key The byte to search for. * @return The index of key if found. If not found, return -(index + 1), where negative indicates * "not found" and the "index + 1" handles the "-0" case. */ public static int unsignedBinarySearch(byte[] a, int fromIndex, int toIndex, byte key) { int unsignedKey = key & 0xff; int low = fromIndex; int high = toIndex - 1; while (low <= high) { int mid = (low + high) >>> 1; int midVal = a[mid] & 0xff; if (midVal < unsignedKey) { low = mid + 1; } else if (midVal > unsignedKey) { high = mid - 1; } else { return mid; // key found } } return -(low + 1); // key not found. } /** * Treat the byte[] as an unsigned series of bytes, most significant bits first. Start by adding * 1 to the rightmost bit/byte and carry over all overflows to the more significant bits/bytes. * * @param input The byte[] to increment. * @return The incremented copy of "in". May be same length or 1 byte longer. */ public static byte[] unsignedCopyAndIncrement(final byte[] input) { byte[] copy = copy(input); if (copy == null) { throw new IllegalArgumentException("cannot increment null array"); } for (int i = copy.length - 1; i >= 0; --i) { if (copy[i] == -1) {// -1 is all 1-bits, which is the unsigned maximum copy[i] = 0; } else { ++copy[i]; return copy; } } // we maxed out the array byte[] out = new byte[copy.length + 1]; out[0] = 1; System.arraycopy(copy, 0, out, 1, copy.length); return out; } public static boolean equals(List<byte[]> a, List<byte[]> b) { if (a == null) { if (b == null) { return true; } return false; } if (b == null) { return false; } if (a.size() != b.size()) { return false; } for (int i = 0; i < a.size(); ++i) { if (!Bytes.equals(a.get(i), b.get(i))) { return false; } } return true; } /** * Returns the index of the first appearance of the value {@code target} in * {@code array}. * * @param array an array of {@code byte} values, possibly empty * @param target a primitive {@code byte} value * @return the least index {@code i} for which {@code array[i] == target}, or * {@code -1} if no such index exists. */ public static int indexOf(byte[] array, byte target) { for (int i = 0; i < array.length; i++) { if (array[i] == target) { return i; } } return -1; } /** * Returns the start position of the first occurrence of the specified {@code * target} within {@code array}, or {@code -1} if there is no such occurrence. * <p/> * <p>More formally, returns the lowest index {@code i} such that {@code * java.util.Arrays.copyOfRange(array, i, i + target.length)} contains exactly * the same elements as {@code target}. * * @param array the array to search for the sequence {@code target} * @param target the array to search for as a sub-sequence of {@code array} */ public static int indexOf(byte[] array, byte[] target) { checkNotNull(array, "array"); checkNotNull(target, "target"); if (target.length == 0) { return 0; } outer: for (int i = 0; i < array.length - target.length + 1; i++) { for (int j = 0; j < target.length; j++) { if (array[i + j] != target[j]) { continue outer; } } return i; } return -1; } /** * @param array an array of {@code byte} values, possibly empty * @param target a primitive {@code byte} value * @return {@code true} if {@code target} is present as an element anywhere in {@code array}. */ public static boolean contains(byte[] array, byte target) { return indexOf(array, target) > -1; } /** * @param array an array of {@code byte} values, possibly empty * @param target an array of {@code byte} * @return {@code true} if {@code target} is present anywhere in {@code array} */ public static boolean contains(byte[] array, byte[] target) { return indexOf(array, target) > -1; } /** * Fill given array with zeros. * * @param b array which needs to be filled with zeros */ public static void zero(byte[] b) { zero(b, 0, b.length); } /** * Fill given array with zeros at the specified position. * * @param b * @param offset * @param length */ public static void zero(byte[] b, int offset, int length) { checkPositionIndex(offset, b.length, "offset"); checkArgument(length > 0, "length must be greater than 0"); checkPositionIndex(offset + length, b.length, "offset + length"); Arrays.fill(b, offset, offset + length, (byte) 0); } private static final SecureRandom RNG = new SecureRandom(); /** * Fill given array with random bytes. * * @param b array which needs to be filled with random bytes */ public static void random(byte[] b) { RNG.nextBytes(b); } /** * Fill given array with random bytes at the specified position. * * @param b * @param offset * @param length */ public static void random(byte[] b, int offset, int length) { checkPositionIndex(offset, b.length, "offset"); checkArgument(length > 0, "length must be greater than 0"); checkPositionIndex(offset + length, b.length, "offset + length"); byte[] buf = new byte[length]; RNG.nextBytes(buf); System.arraycopy(buf, 0, b, offset, length); } /** * Create a max byte array with the specified max byte count * * @param maxByteCount the length of returned byte array * @return the created max byte array */ public static byte[] createMaxByteArray(int maxByteCount) { byte[] maxByteArray = new byte[maxByteCount]; for (int i = 0; i < maxByteArray.length; i++) { maxByteArray[i] = (byte) 0xff; } return maxByteArray; } /** * Create a byte array which is multiple given bytes * * @param srcBytes * @param multiNum * @return byte array */ public static byte[] multiple(byte[] srcBytes, int multiNum) { if (multiNum <= 0) { return new byte[0]; } byte[] result = new byte[srcBytes.length * multiNum]; for (int i = 0; i < multiNum; i++) { System.arraycopy(srcBytes, 0, result, i * srcBytes.length, srcBytes.length); } return result; } /** * Convert a byte array into a hex string * * @param b */ public static String toHex(byte[] b) { checkArgument(b.length > 0, "length must be greater than 0"); return String.format("%x", new BigInteger(1, b)); } /** * Create a byte array from a string of hash digits. The length of the * string must be a multiple of 2 * * @param hex */ public static byte[] fromHex(String hex) { checkArgument(hex.length() > 0, "length must be greater than 0"); checkArgument(hex.length() % 2 == 0, "length must be a multiple of 2"); // Make sure letters are upper case hex = hex.toUpperCase(); byte[] b = new byte[hex.length() / 2]; for (int i = 0; i < b.length; i++) { b[i] = (byte) ((toBinaryFromHex((byte) hex.charAt(2 * i)) << 4) + (toBinaryFromHex((byte) hex.charAt((2 * i + 1))) & 0xff)); } return b; } }