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A Java client tool for Hyperchain
package cn.hyperchain.sdk.common.utils;
import org.bouncycastle.util.encoders.Base64;
import org.bouncycastle.util.encoders.Hex;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
public class ByteUtil {
public static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
/**
* transfer bytes to hex string.
*
* @param data bytes
* @return hex string
*/
public static String toHex(byte[] data) {
return data == null ? "" : Hex.toHexString(data);
}
/**
* transfer hex string to bytes.
*
* @param hex hex string
* @return bytes
*/
public static byte[] fromHex(String hex) {
if (hex == null) {
return EMPTY_BYTE_ARRAY;
}
if (hex.startsWith("0x")) {
hex = hex.substring(2);
}
if ((hex.length() & 1) == 1) {
hex = "0" + hex;
}
return Hex.decode(hex);
}
/**
* decode hex string to utf-8 string.
*
* @param hex hex string
* @return utf-8 string
*/
public static String decodeHex(String hex) {
return new String(fromHex(hex), StandardCharsets.UTF_8);
}
/**
* transfer short type two bytes.
*
* @param n short value
* @return two bytes
*/
public static byte[] shortToBytes(short n) {
return ByteBuffer.allocate(2).putShort(n).array();
}
/**
* transfer int type to four bytes.
*
* @param i int value
* @return four bytes
*/
public static byte[] intToByteArray(int i) {
byte[] result = new byte[4];
result[0] = (byte) ((i >> 24) & 0xFF);
result[1] = (byte) ((i >> 16) & 0xFF);
result[2] = (byte) ((i >> 8) & 0xFF);
result[3] = (byte) (i & 0xFF);
return result;
}
/**
* The regular {@link BigInteger#toByteArray()} method isn't quite what we often need:
* it appends a leading zero to indicate that the number is positive and may need padding.
*
* @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) {
if (b == null) {
return null;
}
byte[] bytes = new byte[numBytes];
byte[] biBytes = b.toByteArray();
int start = (biBytes.length == numBytes + 1) ? 1 : 0;
int length = Math.min(biBytes.length, numBytes);
System.arraycopy(biBytes, start, bytes, numBytes - length, length);
return bytes;
}
/**
* convert BigInteger to signed bytes.
*
* @param b BigInteger
* @param numBytes the desired size
* @return numBytes byte long array
*/
public static byte[] bigIntegerToBytesSigned(BigInteger b, int numBytes) {
if (b == null) {
return null;
}
byte[] bytes = new byte[numBytes];
Arrays.fill(bytes, b.signum() < 0 ? (byte) 0xFF : 0x00);
byte[] biBytes = b.toByteArray();
int start = (biBytes.length == numBytes + 1) ? 1 : 0;
int length = Math.min(biBytes.length, numBytes);
System.arraycopy(biBytes, start, bytes, numBytes - length, length);
return bytes;
}
/**
* @param arrays - arrays to merge.
* @return - merged array
*/
public static byte[] merge(byte[]... arrays) {
int arrCount = 0;
int count = 0;
for (byte[] array : arrays) {
arrCount++;
count += array.length;
}
// Create new array and copy all array contents
byte[] mergedArray = new byte[count];
int start = 0;
for (byte[] array : arrays) {
System.arraycopy(array, 0, mergedArray, start, array.length);
start += array.length;
}
return mergedArray;
}
/**
* transfer BigInteger to 32 bytes.
*
* @param n BigInteger
* @return 32 bytes
*/
public static byte[] biConvert32Bytes(BigInteger n) {
byte[] tmpd = null;
if (n == null) {
return new byte[0];
}
if (n.toByteArray().length == 33) {
tmpd = new byte[32];
System.arraycopy(n.toByteArray(), 1, tmpd, 0, 32);
} else if (n.toByteArray().length == 32) {
tmpd = n.toByteArray();
} else {
tmpd = new byte[32];
for (int i = 0; i < 32 - n.toByteArray().length; i++) {
tmpd[i] = 0;
}
System.arraycopy(n.toByteArray(), 0, tmpd, 32 - n.toByteArray().length, n.toByteArray().length);
}
return tmpd;
}
/**
* todo this is hex encoded value, but method bytesToInteger is not
* Cast hex encoded value from byte[] to BigInteger.
* null is parsed like byte[0]
*
* @param bb byte array contains the values
* @return unsigned positive BigInteger value.
*/
public static BigInteger bytesToBigInteger(byte[] bb) {
return (bb == null || bb.length == 0) ? BigInteger.ZERO : new BigInteger(1, bb);
}
/**
* Cast byte[] to int.
*
* @param bytes byte array contains the values
* @return int value
*/
public static int bytesToInteger(byte[] bytes) {
if (bytes.length > 4) {
throw new IndexOutOfBoundsException("int can only load 4 bytes");
}
int n = 0;
int temp = 0;
for (byte b : bytes) {
n <<= 8;
temp = b & 0xFF;
n |= temp;
}
return n;
}
/**
* transfer hex string to base64 string.
* @param hexOrigin hex string
* @return base64 string
*/
public static String hex2Base64(String hexOrigin) {
return base64(ByteUtil.fromHex(hexOrigin));
}
/**
* encode bytes to base64 string.
* @param data bytes
* @return base64 string
*/
public static String base64(byte[] data) {
return Base64.toBase64String(data);
}
/**
* copy some bytes array from offset.
*
* @param origin origin bytes
* @param offset from offset
* @param length copy length
* @return result
*/
public static byte[] copy(byte[] origin, int offset, int length) {
if (origin.length <= offset || origin.length < offset + length) {
throw new IndexOutOfBoundsException("the origin array length is " + origin.length);
}
byte[] newArray = new byte[length];
System.arraycopy(origin, offset, newArray, 0, length);
return newArray;
}
/**
* Converts int value into a byte array.
*
* @param val - int value to convert
* @return byte[] of length 4, representing the int value
*/
public static byte[] intToBytes(int val) {
return ByteBuffer.allocate(4).putInt(val).array();
}
/**
* Converts long value into a byte array.
*
* @param val - long value to convert
* @return byte[] of length 4, representing the long value
*/
public static byte[] longToBytes(long val) {
byte[] buffer = new byte[8];
for (int i = 0; i < 8; i++) {
int offset = 64 - (i + 1) * 8;
buffer[i] = (byte) ((val >> offset) & 0xff);
}
return buffer;
}
}
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