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/*
* Copyright 2011 Google Inc.
* Copyright 2014 Andreas Schildbach
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.bitcoinj.core;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.util.concurrent.Uninterruptibles.sleepUninterruptibly;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.math.BigInteger;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.TimeZone;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.spongycastle.crypto.digests.RIPEMD160Digest;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.io.BaseEncoding;
/**
* A collection of various utility methods that are helpful for working with the Bitcoin protocol.
* To enable debug logging from the library, run with -Dbitcoinj.logging=true on your command line.
*/
public class Utils {
/** Joiner for concatenating words with a space inbetween. */
public static final Joiner SPACE_JOINER = Joiner.on(" ");
/** Splitter for splitting words on whitespaces. */
public static final Splitter WHITESPACE_SPLITTER = Splitter.on(Pattern.compile("\\s+"));
/** Hex encoding used throughout the framework. Use with HEX.encode(byte[]) or HEX.decode(CharSequence). */
public static final BaseEncoding HEX = BaseEncoding.base16().lowerCase();
/**
* Max initial size of variable length arrays and ArrayLists that could be attacked.
* Avoids this attack: Attacker sends a msg indicating it will contain a huge number (eg 2 billion) elements (eg transaction inputs) and
* forces bitcoinj to try to allocate a huge piece of the memory resulting in OutOfMemoryError.
*/
public static final int MAX_INITIAL_ARRAY_LENGTH = 20;
private static BlockingQueue mockSleepQueue;
private static final Logger log = LoggerFactory.getLogger(Utils.class);
/**
*
* The regular {@link BigInteger#toByteArray()} includes the sign bit of the number and
* might result in an extra byte addition. This method removes this extra byte.
*
*
* Assuming only positive numbers, it's possible to discriminate if an extra byte
* is added by checking if the first element of the array is 0 (0000_0000).
* Due to the minimal representation provided by BigInteger, it means that the bit sign
* is the least significant bit 0000_0000 .
* Otherwise the representation is not minimal.
* For example, if the sign bit is 0000_0000, then the representation is not minimal due to the rightmost zero.
*
* @param b the integer to format into a byte array
* @param numBytes the desired size of the resulting byte array
* @return numBytes byte long array.
*/
public static byte[] bigIntegerToBytes(BigInteger b, int numBytes) {
checkArgument(b.signum() >= 0, "b must be positive or zero");
checkArgument(numBytes > 0, "numBytes must be positive");
byte[] src = b.toByteArray();
byte[] dest = new byte[numBytes];
boolean isFirstByteOnlyForSign = src[0] == 0;
int length = isFirstByteOnlyForSign ? src.length - 1 : src.length;
checkArgument(length <= numBytes, "The given number does not fit in " + numBytes);
int srcPos = isFirstByteOnlyForSign ? 1 : 0;
int destPos = numBytes - length;
System.arraycopy(src, srcPos, dest, destPos, length);
return dest;
}
/** Write 2 bytes to the byte array (starting at the offset) as unsigned 16-bit integer in little endian format. */
public static void uint16ToByteArrayLE(int val, byte[] out, int offset) {
out[offset] = (byte) (0xFF & val);
out[offset + 1] = (byte) (0xFF & (val >> 8));
}
/** Write 4 bytes to the byte array (starting at the offset) as unsigned 32-bit integer in little endian format. */
public static void uint32ToByteArrayLE(long val, byte[] out, int offset) {
out[offset] = (byte) (0xFF & val);
out[offset + 1] = (byte) (0xFF & (val >> 8));
out[offset + 2] = (byte) (0xFF & (val >> 16));
out[offset + 3] = (byte) (0xFF & (val >> 24));
}
/** Write 4 bytes to the byte array (starting at the offset) as unsigned 32-bit integer in big endian format. */
public static void uint32ToByteArrayBE(long val, byte[] out, int offset) {
out[offset] = (byte) (0xFF & (val >> 24));
out[offset + 1] = (byte) (0xFF & (val >> 16));
out[offset + 2] = (byte) (0xFF & (val >> 8));
out[offset + 3] = (byte) (0xFF & val);
}
/** Write 8 bytes to the byte array (starting at the offset) as signed 64-bit integer in little endian format. */
public static void int64ToByteArrayLE(long val, byte[] out, int offset) {
out[offset] = (byte) (0xFF & val);
out[offset + 1] = (byte) (0xFF & (val >> 8));
out[offset + 2] = (byte) (0xFF & (val >> 16));
out[offset + 3] = (byte) (0xFF & (val >> 24));
out[offset + 4] = (byte) (0xFF & (val >> 32));
out[offset + 5] = (byte) (0xFF & (val >> 40));
out[offset + 6] = (byte) (0xFF & (val >> 48));
out[offset + 7] = (byte) (0xFF & (val >> 56));
}
/** Write 2 bytes to the output stream as unsigned 16-bit integer in little endian format. */
public static void uint16ToByteStreamLE(int val, OutputStream stream) throws IOException {
stream.write((int) (0xFF & val));
stream.write((int) (0xFF & (val >> 8)));
}
/** Write 2 bytes to the output stream as unsigned 16-bit integer in big endian format. */
public static void uint16ToByteStreamBE(int val, OutputStream stream) throws IOException {
stream.write((int) (0xFF & (val >> 8)));
stream.write((int) (0xFF & val));
}
/** Write 4 bytes to the output stream as unsigned 32-bit integer in little endian format. */
public static void uint32ToByteStreamLE(long val, OutputStream stream) throws IOException {
stream.write((int) (0xFF & val));
stream.write((int) (0xFF & (val >> 8)));
stream.write((int) (0xFF & (val >> 16)));
stream.write((int) (0xFF & (val >> 24)));
}
/** Write 4 bytes to the output stream as unsigned 32-bit integer in big endian format. */
public static void uint32ToByteStreamBE(long val, OutputStream stream) throws IOException {
stream.write((int) (0xFF & (val >> 24)));
stream.write((int) (0xFF & (val >> 16)));
stream.write((int) (0xFF & (val >> 8)));
stream.write((int) (0xFF & val));
}
/** Write 8 bytes to the output stream as signed 64-bit integer in little endian format. */
public static void int64ToByteStreamLE(long val, OutputStream stream) throws IOException {
stream.write((int) (0xFF & val));
stream.write((int) (0xFF & (val >> 8)));
stream.write((int) (0xFF & (val >> 16)));
stream.write((int) (0xFF & (val >> 24)));
stream.write((int) (0xFF & (val >> 32)));
stream.write((int) (0xFF & (val >> 40)));
stream.write((int) (0xFF & (val >> 48)));
stream.write((int) (0xFF & (val >> 56)));
}
/** Write 8 bytes to the output stream as unsigned 64-bit integer in little endian format. */
public static void uint64ToByteStreamLE(BigInteger val, OutputStream stream) throws IOException {
byte[] bytes = val.toByteArray();
if (bytes.length > 8) {
throw new RuntimeException("Input too large to encode into a uint64");
}
bytes = reverseBytes(bytes);
stream.write(bytes);
if (bytes.length < 8) {
for (int i = 0; i < 8 - bytes.length; i++)
stream.write(0);
}
}
/** Parse 2 bytes from the byte array (starting at the offset) as unsigned 16-bit integer in little endian format. */
public static int readUint16(byte[] bytes, int offset) {
return (bytes[offset] & 0xff) |
((bytes[offset + 1] & 0xff) << 8);
}
/** Parse 4 bytes from the byte array (starting at the offset) as unsigned 32-bit integer in little endian format. */
public static long readUint32(byte[] bytes, int offset) {
return (bytes[offset] & 0xffl) |
((bytes[offset + 1] & 0xffl) << 8) |
((bytes[offset + 2] & 0xffl) << 16) |
((bytes[offset + 3] & 0xffl) << 24);
}
/** Parse 8 bytes from the byte array (starting at the offset) as signed 64-bit integer in little endian format. */
public static long readInt64(byte[] bytes, int offset) {
return (bytes[offset] & 0xffl) |
((bytes[offset + 1] & 0xffl) << 8) |
((bytes[offset + 2] & 0xffl) << 16) |
((bytes[offset + 3] & 0xffl) << 24) |
((bytes[offset + 4] & 0xffl) << 32) |
((bytes[offset + 5] & 0xffl) << 40) |
((bytes[offset + 6] & 0xffl) << 48) |
((bytes[offset + 7] & 0xffl) << 56);
}
/** Parse 4 bytes from the byte array (starting at the offset) as unsigned 32-bit integer in big endian format. */
public static long readUint32BE(byte[] bytes, int offset) {
return ((bytes[offset] & 0xffl) << 24) |
((bytes[offset + 1] & 0xffl) << 16) |
((bytes[offset + 2] & 0xffl) << 8) |
(bytes[offset + 3] & 0xffl);
}
/** Parse 2 bytes from the byte array (starting at the offset) as unsigned 16-bit integer in big endian format. */
public static int readUint16BE(byte[] bytes, int offset) {
return ((bytes[offset] & 0xff) << 8) |
(bytes[offset + 1] & 0xff);
}
/** Parse 2 bytes from the stream as unsigned 16-bit integer in little endian format. */
public static int readUint16FromStream(InputStream is) {
try {
return (is.read() & 0xff) |
((is.read() & 0xff) << 8);
} catch (IOException x) {
throw new RuntimeException(x);
}
}
/** Parse 4 bytes from the stream as unsigned 32-bit integer in little endian format. */
public static long readUint32FromStream(InputStream is) {
try {
return (is.read() & 0xffl) |
((is.read() & 0xffl) << 8) |
((is.read() & 0xffl) << 16) |
((is.read() & 0xffl) << 24);
} catch (IOException x) {
throw new RuntimeException(x);
}
}
/**
* Returns a copy of the given byte array in reverse order.
*/
public static byte[] reverseBytes(byte[] bytes) {
// We could use the XOR trick here but it's easier to understand if we don't. If we find this is really a
// performance issue the matter can be revisited.
byte[] buf = new byte[bytes.length];
for (int i = 0; i < bytes.length; i++)
buf[i] = bytes[bytes.length - 1 - i];
return buf;
}
/**
* Calculates RIPEMD160(SHA256(input)). This is used in Address calculations.
*/
public static byte[] sha256hash160(byte[] input) {
byte[] sha256 = Sha256Hash.hash(input);
RIPEMD160Digest digest = new RIPEMD160Digest();
digest.update(sha256, 0, sha256.length);
byte[] out = new byte[20];
digest.doFinal(out, 0);
return out;
}
/**
* MPI encoded numbers are produced by the OpenSSL BN_bn2mpi function. They consist of
* a 4 byte big endian length field, followed by the stated number of bytes representing
* the number in big endian format (with a sign bit).
* @param hasLength can be set to false if the given array is missing the 4 byte length field
*/
public static BigInteger decodeMPI(byte[] mpi, boolean hasLength) {
byte[] buf;
if (hasLength) {
int length = (int) readUint32BE(mpi, 0);
buf = new byte[length];
System.arraycopy(mpi, 4, buf, 0, length);
} else
buf = mpi;
if (buf.length == 0)
return BigInteger.ZERO;
boolean isNegative = (buf[0] & 0x80) == 0x80;
if (isNegative)
buf[0] &= 0x7f;
BigInteger result = new BigInteger(buf);
return isNegative ? result.negate() : result;
}
/**
* MPI encoded numbers are produced by the OpenSSL BN_bn2mpi function. They consist of
* a 4 byte big endian length field, followed by the stated number of bytes representing
* the number in big endian format (with a sign bit).
* @param includeLength indicates whether the 4 byte length field should be included
*/
public static byte[] encodeMPI(BigInteger value, boolean includeLength) {
if (value.equals(BigInteger.ZERO)) {
if (!includeLength)
return new byte[] {};
else
return new byte[] {0x00, 0x00, 0x00, 0x00};
}
boolean isNegative = value.signum() < 0;
if (isNegative)
value = value.negate();
byte[] array = value.toByteArray();
int length = array.length;
if ((array[0] & 0x80) == 0x80)
length++;
if (includeLength) {
byte[] result = new byte[length + 4];
System.arraycopy(array, 0, result, length - array.length + 3, array.length);
uint32ToByteArrayBE(length, result, 0);
if (isNegative)
result[4] |= 0x80;
return result;
} else {
byte[] result;
if (length != array.length) {
result = new byte[length];
System.arraycopy(array, 0, result, 1, array.length);
}else
result = array;
if (isNegative)
result[0] |= 0x80;
return result;
}
}
/**
* The "compact" format is a representation of a whole number N using an unsigned 32 bit number similar to a
* floating point format. The most significant 8 bits are the unsigned exponent of base 256. This exponent can
* be thought of as "number of bytes of N". The lower 23 bits are the mantissa. Bit number 24 (0x800000) represents
* the sign of N. Therefore, N = (-1^sign) * mantissa * 256^(exponent-3).
*
* Satoshi's original implementation used BN_bn2mpi() and BN_mpi2bn(). MPI uses the most significant bit of the
* first byte as sign. Thus 0x1234560000 is compact 0x05123456 and 0xc0de000000 is compact 0x0600c0de. Compact
* 0x05c0de00 would be -0x40de000000.
*
* Bitcoin only uses this "compact" format for encoding difficulty targets, which are unsigned 256bit quantities.
* Thus, all the complexities of the sign bit and using base 256 are probably an implementation accident.
*/
public static BigInteger decodeCompactBits(long compact) {
int size = ((int) (compact >> 24)) & 0xFF;
byte[] bytes = new byte[4 + size];
bytes[3] = (byte) size;
if (size >= 1) bytes[4] = (byte) ((compact >> 16) & 0xFF);
if (size >= 2) bytes[5] = (byte) ((compact >> 8) & 0xFF);
if (size >= 3) bytes[6] = (byte) (compact & 0xFF);
return decodeMPI(bytes, true);
}
/**
* @see Utils#decodeCompactBits(long)
*/
public static long encodeCompactBits(BigInteger value) {
long result;
int size = value.toByteArray().length;
if (size <= 3)
result = value.longValue() << 8 * (3 - size);
else
result = value.shiftRight(8 * (size - 3)).longValue();
// The 0x00800000 bit denotes the sign.
// Thus, if it is already set, divide the mantissa by 256 and increase the exponent.
if ((result & 0x00800000L) != 0) {
result >>= 8;
size++;
}
result |= size << 24;
result |= value.signum() == -1 ? 0x00800000 : 0;
return result;
}
/**
* If non-null, overrides the return value of now().
*/
private static volatile Date mockTime;
/**
* Advances (or rewinds) the mock clock by the given number of seconds.
*/
public static Date rollMockClock(int seconds) {
return rollMockClockMillis(seconds * 1000);
}
/**
* Advances (or rewinds) the mock clock by the given number of milliseconds.
*/
public static Date rollMockClockMillis(long millis) {
if (mockTime == null)
throw new IllegalStateException("You need to use setMockClock() first.");
mockTime = new Date(mockTime.getTime() + millis);
return mockTime;
}
/**
* Sets the mock clock to the current time.
*/
public static void setMockClock() {
mockTime = new Date();
}
/**
* Sets the mock clock to the given time (in seconds).
*/
public static void setMockClock(long mockClockSeconds) {
mockTime = new Date(mockClockSeconds * 1000);
}
/**
* Clears the mock clock and sleep
*/
public static void resetMocking() {
mockTime = null;
mockSleepQueue = null;
}
/**
* Returns the current time, or a mocked out equivalent.
*/
public static Date now() {
return mockTime != null ? mockTime : new Date();
}
/**
* Returns the current time in milliseconds since the epoch, or a mocked out equivalent.
*/
public static long currentTimeMillis() {
return mockTime != null ? mockTime.getTime() : System.currentTimeMillis();
}
/**
* Returns the current time in seconds since the epoch, or a mocked out equivalent.
*/
public static long currentTimeSeconds() {
return currentTimeMillis() / 1000;
}
private static final TimeZone UTC = TimeZone.getTimeZone("UTC");
/**
* Formats a given date+time value to an ISO 8601 string.
* @param dateTime value to format, as a Date
*/
public static String dateTimeFormat(Date dateTime) {
DateFormat iso8601 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US);
iso8601.setTimeZone(UTC);
return iso8601.format(dateTime);
}
/**
* Formats a given date+time value to an ISO 8601 string.
* @param dateTime value to format, unix time (ms)
*/
public static String dateTimeFormat(long dateTime) {
DateFormat iso8601 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US);
iso8601.setTimeZone(UTC);
return iso8601.format(dateTime);
}
// 00000001, 00000010, 00000100, 00001000, ...
private static final int[] bitMask = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};
/** Checks if the given bit is set in data, using little endian (not the same as Java native big endian) */
public static boolean checkBitLE(byte[] data, int index) {
return (data[index >>> 3] & bitMask[7 & index]) != 0;
}
/** Sets the given bit in data to one, using little endian (not the same as Java native big endian) */
public static void setBitLE(byte[] data, int index) {
data[index >>> 3] |= bitMask[7 & index];
}
/** Sleep for a span of time, or mock sleep if enabled */
public static void sleep(long millis) {
if (mockSleepQueue == null) {
sleepUninterruptibly(millis, TimeUnit.MILLISECONDS);
} else {
try {
boolean isMultiPass = mockSleepQueue.take();
rollMockClockMillis(millis);
if (isMultiPass)
mockSleepQueue.offer(true);
} catch (InterruptedException e) {
// Ignored.
}
}
}
/** Enable or disable mock sleep. If enabled, set mock time to current time. */
public static void setMockSleep(boolean isEnable) {
if (isEnable) {
mockSleepQueue = new ArrayBlockingQueue<>(1);
mockTime = new Date(System.currentTimeMillis());
} else {
mockSleepQueue = null;
}
}
/** Let sleeping thread pass the synchronization point. */
public static void passMockSleep() {
mockSleepQueue.offer(false);
}
/** Let the sleeping thread pass the synchronization point any number of times. */
public static void finishMockSleep() {
if (mockSleepQueue != null) {
mockSleepQueue.offer(true);
}
}
private enum Runtime {
ANDROID, OPENJDK, ORACLE_JAVA
}
private enum OS {
LINUX, WINDOWS, MAC_OS
}
private static Runtime runtime = null;
private static OS os = null;
static {
String runtimeProp = System.getProperty("java.runtime.name", "").toLowerCase(Locale.US);
if (runtimeProp.equals(""))
runtime = null;
else if (runtimeProp.contains("android"))
runtime = Runtime.ANDROID;
else if (runtimeProp.contains("openjdk"))
runtime = Runtime.OPENJDK;
else if (runtimeProp.contains("java(tm) se"))
runtime = Runtime.ORACLE_JAVA;
else
log.info("Unknown java.runtime.name '{}'", runtimeProp);
String osProp = System.getProperty("os.name", "").toLowerCase(Locale.US);
if (osProp.equals(""))
os = null;
else if (osProp.contains("linux"))
os = OS.LINUX;
else if (osProp.contains("win"))
os = OS.WINDOWS;
else if (osProp.contains("mac"))
os = OS.MAC_OS;
else
log.info("Unknown os.name '{}'", runtimeProp);
}
public static boolean isAndroidRuntime() {
return runtime == Runtime.ANDROID;
}
public static boolean isOpenJDKRuntime() {
return runtime == Runtime.OPENJDK;
}
public static boolean isOracleJavaRuntime() {
return runtime == Runtime.ORACLE_JAVA;
}
public static boolean isLinux() {
return os == OS.LINUX;
}
public static boolean isWindows() {
return os == OS.WINDOWS;
}
public static boolean isMac() {
return os == OS.MAC_OS;
}
public static String toString(List stack) {
List parts = new ArrayList<>(stack.size());
for (byte[] push : stack)
parts.add('[' + HEX.encode(push) + ']');
return SPACE_JOINER.join(parts);
}
}