| package com.alibaba.jstorm.metric; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.io.UnsupportedEncodingException; |
| import java.math.BigDecimal; |
| import java.math.BigInteger; |
| import java.nio.ByteBuffer; |
| |
| public class Bytes { |
| |
| private static final Logger LOG = LoggerFactory.getLogger(Bytes.class); |
| |
| /** |
| * Size of boolean in bytes |
| */ |
| public static final int SIZEOF_BOOLEAN = Byte.SIZE / Byte.SIZE; |
| |
| /** |
| * Size of byte in bytes |
| */ |
| public static final int SIZEOF_BYTE = SIZEOF_BOOLEAN; |
| |
| /** |
| * Size of char in bytes |
| */ |
| public static final int SIZEOF_CHAR = Character.SIZE / Byte.SIZE; |
| |
| /** |
| * Size of double in bytes |
| */ |
| public static final int SIZEOF_DOUBLE = Double.SIZE / Byte.SIZE; |
| |
| /** |
| * Size of float in bytes |
| */ |
| public static final int SIZEOF_FLOAT = Float.SIZE / Byte.SIZE; |
| |
| /** |
| * Size of int in bytes |
| */ |
| public static final int SIZEOF_INT = Integer.SIZE / Byte.SIZE; |
| |
| /** |
| * Size of long in bytes |
| */ |
| public static final int SIZEOF_LONG = Long.SIZE / Byte.SIZE; |
| |
| /** |
| * Size of short in bytes |
| */ |
| public static final int SIZEOF_SHORT = Short.SIZE / Byte.SIZE; |
| |
| |
| /** |
| * 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; |
| |
| |
| /** |
| * Put bytes at the specified byte array position. |
| * |
| * @param tgtBytes the byte array |
| * @param tgtOffset position in the array |
| * @param srcBytes array to write out |
| * @param srcOffset source offset |
| * @param srcLength source length |
| * @return incremented offset |
| */ |
| public static int putBytes(byte[] tgtBytes, int tgtOffset, byte[] srcBytes, |
| int srcOffset, int srcLength) { |
| System.arraycopy(srcBytes, srcOffset, tgtBytes, tgtOffset, srcLength); |
| return tgtOffset + srcLength; |
| } |
| |
| /** |
| * Write a single byte out to the specified byte array position. |
| * |
| * @param bytes the byte array |
| * @param offset position in the array |
| * @param b byte to write out |
| * @return incremented offset |
| */ |
| public static int putByte(byte[] bytes, int offset, byte b) { |
| bytes[offset] = b; |
| return offset + 1; |
| } |
| |
| /** |
| * Returns a new byte array, copied from the passed ByteBuffer. |
| * |
| * @param bb A ByteBuffer |
| * @return the byte array |
| */ |
| public static byte[] toBytes(ByteBuffer bb) { |
| int length = bb.limit(); |
| byte[] result = new byte[length]; |
| System.arraycopy(bb.array(), bb.arrayOffset(), result, 0, length); |
| return result; |
| } |
| |
| public static byte[] copyBytes(final byte[] bytes, int offset, int length) { |
| if (offset + length > bytes.length) { |
| throw explainWrongLengthOrOffset(bytes, offset, length, length); |
| } |
| byte[] result = new byte[length]; |
| System.arraycopy(bytes, offset, result, 0, length); |
| return result; |
| } |
| |
| /** |
| * 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, from its array offset to its limit, to |
| * a string. The position and the mark are ignored. |
| * |
| * @param buf a byte buffer |
| * @return a string representation of the buffer's binary contents |
| */ |
| public static String toStringBinary(ByteBuffer buf) { |
| if (buf == null) |
| return "null"; |
| return toStringBinary(buf.array(), buf.arrayOffset(), buf.limit()); |
| } |
| |
| /** |
| * Write a printable representation of a byte array. Non-printable |
| * characters are hex escaped in the format \\x%02X, eg: |
| * \x00 \x05 etc |
| * |
| * @param b array to write out |
| * @param off offset to start at |
| * @param len length to write |
| * @return string output |
| */ |
| public static String toStringBinary(final byte[] b, int off, int len) { |
| StringBuilder result = new StringBuilder(); |
| try { |
| String first = new String(b, off, len, "ISO-8859-1"); |
| for (int i = 0; i < first.length(); ++i) { |
| int ch = first.charAt(i) & 0xFF; |
| if ((ch >= '0' && ch <= '9') |
| || (ch >= 'A' && ch <= 'Z') |
| || (ch >= 'a' && ch <= 'z') |
| || " `~!@#$%^&*()-_=+[]{}\\|;:'\",.<>/?".indexOf(ch) >= 0) { |
| result.append(first.charAt(i)); |
| } else { |
| result.append(String.format("\\x%02X", ch)); |
| } |
| } |
| } catch (UnsupportedEncodingException e) { |
| LOG.error("ISO-8859-1 not supported?", e); |
| } |
| return result.toString(); |
| } |
| |
| private static boolean isHexDigit(char c) { |
| return |
| (c >= 'A' && c <= 'F') || |
| (c >= '0' && c <= '9'); |
| } |
| |
| /** |
| * Takes a ASCII digit in the range A-F0-9 and returns |
| * the corresponding integer/ordinal value. |
| * |
| * @param ch The hex digit. |
| * @return The converted hex value as a byte. |
| */ |
| public static byte toBinaryFromHex(byte ch) { |
| if (ch >= 'A' && ch <= 'F') |
| return (byte) ((byte) 10 + (byte) (ch - 'A')); |
| // else |
| return (byte) (ch - '0'); |
| } |
| |
| public static byte[] toBytesBinary(String in) { |
| // this may be bigger than we need, but lets be safe. |
| byte[] b = new byte[in.length()]; |
| int size = 0; |
| for (int i = 0; i < in.length(); ++i) { |
| char ch = in.charAt(i); |
| if (ch == '\\' && 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; |
| } |
| |
| /** |
| * 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; |
| } |
| |
| public static boolean toBoolean(final byte[] bytes, int offset, int length) { |
| if (length != SIZEOF_BOOLEAN || offset + length > bytes.length) { |
| throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_BOOLEAN); |
| } |
| return bytes[offset] != (byte) 0; |
| } |
| |
| /** |
| * Convert a long value to a byte array using big-endian. |
| * |
| * @param val value to convert |
| * @return the byte array |
| */ |
| public static byte[] toBytes(long val) { |
| byte[] b = new byte[8]; |
| for (int i = 7; i > 0; i--) { |
| b[i] = (byte) val; |
| val >>>= 8; |
| } |
| b[0] = (byte) val; |
| return b; |
| } |
| |
| /** |
| * Converts a byte array to a long value. Reverses |
| * {@link #toBytes(long)} |
| * |
| * @param bytes array |
| * @return the long value |
| */ |
| public static long toLong(byte[] bytes) { |
| return toLong(bytes, 0, SIZEOF_LONG); |
| } |
| |
| /** |
| * Converts a byte array to a long value. Assumes there will be |
| * {@link #SIZEOF_LONG} bytes available. |
| * |
| * @param bytes bytes |
| * @param offset offset |
| * @return the long value |
| */ |
| public static long toLong(byte[] bytes, int offset) { |
| return toLong(bytes, offset, SIZEOF_LONG); |
| } |
| |
| /** |
| * Converts a byte array to a long value. |
| * |
| * @param bytes array of bytes |
| * @param offset offset into array |
| * @param length length of data (must be {@link #SIZEOF_LONG}) |
| * @return the long value |
| * @throws IllegalArgumentException if length is not {@link #SIZEOF_LONG} or |
| * if there's not enough room in the array at the offset indicated. |
| */ |
| public static long toLong(byte[] bytes, int offset, final int length) { |
| if (length != SIZEOF_LONG || offset + length > bytes.length) { |
| throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_LONG); |
| } |
| long l = 0; |
| for (int i = offset; i < offset + length; i++) { |
| l <<= 8; |
| l ^= bytes[i] & 0xFF; |
| } |
| return l; |
| } |
| |
| private static IllegalArgumentException |
| explainWrongLengthOrOffset(final byte[] bytes, |
| final int offset, |
| final int length, |
| final int expectedLength) { |
| String reason; |
| if (length != expectedLength) { |
| reason = "Wrong length: " + length + ", expected " + expectedLength; |
| } else { |
| reason = "offset (" + offset + ") + length (" + length + ") exceed the" |
| + " capacity of the array: " + bytes.length; |
| } |
| return new IllegalArgumentException(reason); |
| } |
| |
| /** |
| * Put a long value out to the specified byte array position. |
| * |
| * @param bytes the byte array |
| * @param offset position in the array |
| * @param val long to write out |
| * @return incremented offset |
| * @throws IllegalArgumentException if the byte array given doesn't have |
| * enough room at the offset specified. |
| */ |
| public static int putLong(byte[] bytes, int offset, long val) { |
| if (bytes.length - offset < SIZEOF_LONG) { |
| throw new IllegalArgumentException("Not enough room to put a long at" |
| + " offset " + offset + " in a " + bytes.length + " byte array"); |
| } |
| for (int i = offset + 7; i > offset; i--) { |
| bytes[i] = (byte) val; |
| val >>>= 8; |
| } |
| bytes[offset] = (byte) val; |
| return offset + SIZEOF_LONG; |
| } |
| |
| /** |
| * Presumes float encoded as IEEE 754 floating-point "single format" |
| * |
| * @param bytes byte array |
| * @return Float made from passed byte array. |
| */ |
| public static float toFloat(byte[] bytes) { |
| return toFloat(bytes, 0); |
| } |
| |
| /** |
| * Presumes float encoded as IEEE 754 floating-point "single format" |
| * |
| * @param bytes array to convert |
| * @param offset offset into array |
| * @return Float made from passed byte array. |
| */ |
| public static float toFloat(byte[] bytes, int offset) { |
| return Float.intBitsToFloat(toInt(bytes, offset, SIZEOF_INT)); |
| } |
| |
| /** |
| * @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 |
| * |
| * @param val value |
| * @return the byte array |
| */ |
| public static byte[] toBytes(int val) { |
| byte[] b = new byte[4]; |
| for (int i = 3; i > 0; i--) { |
| b[i] = (byte) val; |
| val >>>= 8; |
| } |
| b[0] = (byte) val; |
| return b; |
| } |
| |
| /** |
| * Converts a byte array to an int value |
| * |
| * @param bytes byte array |
| * @return the int value |
| */ |
| public static int toInt(byte[] bytes) { |
| return toInt(bytes, 0, SIZEOF_INT); |
| } |
| |
| /** |
| * Converts a byte array to an int value |
| * |
| * @param bytes byte array |
| * @param offset offset into array |
| * @return the int value |
| */ |
| public static int toInt(byte[] bytes, int offset) { |
| return toInt(bytes, offset, SIZEOF_INT); |
| } |
| |
| /** |
| * Converts a byte array to an int value |
| * |
| * @param bytes byte array |
| * @param offset offset into array |
| * @param length length of int (has to be {@link #SIZEOF_INT}) |
| * @return the int value |
| * @throws IllegalArgumentException if length is not {@link #SIZEOF_INT} or |
| * if there's not enough room in the array at the offset indicated. |
| */ |
| public static int toInt(byte[] bytes, int offset, final int length) { |
| if (length != SIZEOF_INT || offset + length > bytes.length) { |
| throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_INT); |
| } |
| int n = 0; |
| for (int i = offset; i < (offset + length); i++) { |
| n <<= 8; |
| n ^= bytes[i] & 0xFF; |
| } |
| return n; |
| } |
| |
| /** |
| * Put an int value out to the specified byte array position. |
| * |
| * @param bytes the byte array |
| * @param offset position in the array |
| * @param val int to write out |
| * @return incremented offset |
| * @throws IllegalArgumentException if the byte array given doesn't have |
| * enough room at the offset specified. |
| */ |
| public static int putInt(byte[] bytes, int offset, int val) { |
| if (bytes.length - offset < SIZEOF_INT) { |
| throw new IllegalArgumentException("Not enough room to put an int at" |
| + " offset " + offset + " in a " + bytes.length + " byte array"); |
| } |
| for (int i = offset + 3; i > offset; i--) { |
| bytes[i] = (byte) val; |
| val >>>= 8; |
| } |
| bytes[offset] = (byte) val; |
| return offset + SIZEOF_INT; |
| } |
| |
| /** |
| * Convert a short value to a byte array of {@link #SIZEOF_SHORT} bytes long. |
| * |
| * @param val value |
| * @return the byte array |
| */ |
| public static byte[] toBytes(short val) { |
| byte[] b = new byte[SIZEOF_SHORT]; |
| b[1] = (byte) val; |
| val >>= 8; |
| b[0] = (byte) val; |
| return b; |
| } |
| |
| /** |
| * Converts a byte array to a short value |
| * |
| * @param bytes byte array |
| * @return the short value |
| */ |
| public static short toShort(byte[] bytes) { |
| return toShort(bytes, 0, SIZEOF_SHORT); |
| } |
| |
| /** |
| * Converts a byte array to a short value |
| * |
| * @param bytes byte array |
| * @param offset offset into array |
| * @return the short value |
| */ |
| public static short toShort(byte[] bytes, int offset) { |
| return toShort(bytes, offset, SIZEOF_SHORT); |
| } |
| |
| /** |
| * Converts a byte array to a short value |
| * |
| * @param bytes byte array |
| * @param offset offset into array |
| * @param length length, has to be {@link #SIZEOF_SHORT} |
| * @return the short value |
| * @throws IllegalArgumentException if length is not {@link #SIZEOF_SHORT} |
| * or if there's not enough room in the array at the offset indicated. |
| */ |
| public static short toShort(byte[] bytes, int offset, final int length) { |
| if (length != SIZEOF_SHORT || offset + length > bytes.length) { |
| throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_SHORT); |
| } |
| short n = 0; |
| n ^= bytes[offset] & 0xFF; |
| n <<= 8; |
| n ^= bytes[offset + 1] & 0xFF; |
| return n; |
| } |
| |
| /** |
| * This method will get a sequence of bytes from pos -> limit, |
| * but will restore pos after. |
| * |
| * @param buf |
| * @return byte array |
| */ |
| public static byte[] getBytes(ByteBuffer buf) { |
| int savedPos = buf.position(); |
| byte[] newBytes = new byte[buf.remaining()]; |
| buf.get(newBytes); |
| buf.position(savedPos); |
| return newBytes; |
| } |
| |
| /** |
| * Put a short value out to the specified byte array position. |
| * |
| * @param bytes the byte array |
| * @param offset position in the array |
| * @param val short to write out |
| * @return incremented offset |
| * @throws IllegalArgumentException if the byte array given doesn't have |
| * enough room at the offset specified. |
| */ |
| public static int putShort(byte[] bytes, int offset, short val) { |
| if (bytes.length - offset < SIZEOF_SHORT) { |
| throw new IllegalArgumentException("Not enough room to put a short at" |
| + " offset " + offset + " in a " + bytes.length + " byte array"); |
| } |
| bytes[offset + 1] = (byte) val; |
| val >>= 8; |
| bytes[offset] = (byte) val; |
| return offset + SIZEOF_SHORT; |
| } |
| |
| public static byte toByte(byte[] bytes, int offset, int length) { |
| if (length != SIZEOF_BYTE || offset + length > bytes.length) { |
| throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_BYTE); |
| } |
| return bytes[offset]; |
| } |
| |
| |
| /** |
| * 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 compareByteArrayInLexOrder(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 compareByteArrayInLexOrder(buffer1, offset1, length1, buffer2, offset2, length2); |
| } |
| |
| public static int compareByteArrayInLexOrder(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; |
| } |
| |
| /** |
| * @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 compareByteArrayInLexOrder(left, leftOffset, leftLen, right, rightOffset, rightLen) == 0; |
| } |
| |
| |
| /** |
| * Return true if the byte array on the right is a prefix of the byte |
| * array on the left. |
| */ |
| public static boolean startsWith(byte[] bytes, byte[] prefix) { |
| return bytes != null && prefix != null && |
| bytes.length >= prefix.length && |
| compareByteArrayInLexOrder(bytes, 0, prefix.length, prefix, 0, prefix.length) == 0; |
| } |
| |
| public static int hashCode(final byte[] b) { |
| return hashCode(b, b.length); |
| } |
| |
| public static int hashCode(final byte[] b, final int length) { |
| return hashBytes(b, length); |
| } |
| |
| /** |
| * Compute hash for binary data. |
| */ |
| public static int hashBytes(byte[] bytes, int offset, int length) { |
| int hash = 1; |
| for (int i = offset; i < offset + length; i++) |
| hash = (31 * hash) + (int) bytes[i]; |
| return hash; |
| } |
| |
| /** |
| * Compute hash for binary data. |
| */ |
| public static int hashBytes(byte[] bytes, int length) { |
| return hashBytes(bytes, 0, length); |
| } |
| |
| /** |
| * @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; |
| } |
| |
| /** |
| * http://tools.ietf.org/html/rfc3629 |
| */ |
| public static int stringtoUTF8Bytes(String str, byte[] buffer) { |
| int index = 0; |
| for (int i = 0; i < str.length(); i++) { |
| char strChar = str.charAt(i); |
| if ((strChar & 0xFF80) == 0) { |
| // (00000000 00000000 - 00000000 01111111) -> 0xxxxxxx |
| buffer[index++] = (byte) (strChar & 0x00FF); |
| } else if ((strChar & 0xF800) == 0) { |
| // (00000000 10000000 - 00000111 11111111) -> 110xxxxx 10xxxxxx |
| buffer[index++] = (byte) ((strChar >> 6) | 0x00c0); |
| buffer[index++] = (byte) ((strChar & 0x003F) | 0x0080); |
| } else { |
| // (00001000 00000000 - 11111111 11111111) -> 1110xxxx 10xxxxxx 10xxxxxx |
| buffer[index++] = (byte) ((strChar >> 12) | 0x00e0); |
| buffer[index++] = (byte) (((strChar >> 6) & 0x003F) | 0x0080); |
| buffer[index++] = (byte) ((strChar & 0x003F) | 0x0080); |
| } |
| } |
| return index; |
| } |
| } |