com.huaweicloud.dis.core.util.BinaryUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2010 the original author or authors.
*
* 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 com.huaweicloud.dis.core.util;
import java.io.ByteArrayInputStream;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.Locale;
/**
* Utilities for encoding and decoding binary data to and from different forms.
*/
public class BinaryUtils {
/**
* Converts byte data to a Hex-encoded string.
*
* @param data
* data to hex encode.
*
* @return hex-encoded string.
*/
public static String toHex(byte[] data) {
StringBuilder sb = new StringBuilder(data.length * 2);
for (byte b : data) {
String hex = Integer.toHexString(b);
if (hex.length() == 1) {
// Append leading zero.
sb.append("0");
} else if (hex.length() == 8) {
// Remove ff prefix from negative numbers.
hex = hex.substring(6);
}
sb.append(hex);
}
return sb.toString().toLowerCase(Locale.getDefault());
}
/**
* Converts a Hex-encoded data string to the original byte data.
*
* @param hexData
* hex-encoded data to decode.
* @return decoded data from the hex string.
*/
public static byte[] fromHex(String hexData) {
byte[] result = new byte[(hexData.length() + 1) / 2];
String hexNumber = null;
int stringOffset = 0;
int byteOffset = 0;
while (stringOffset < hexData.length()) {
hexNumber = hexData.substring(stringOffset, stringOffset + 2);
stringOffset += 2;
result[byteOffset++] = (byte) Integer.parseInt(hexNumber, 16);
}
return result;
}
/**
* Converts byte data to a Base64-encoded string.
*
* @param data
* data to Base64 encode.
* @return encoded Base64 string.
*/
public static String toBase64(byte[] data) {
return Base64.encodeAsString(data);
}
/**
* Converts a Base64-encoded string to the original byte data.
*
* @param b64Data
* a Base64-encoded string to decode.
*
* @return bytes decoded from a Base64 string.
*/
public static byte[] fromBase64(String b64Data) {
return b64Data == null ? null : Base64.decode(b64Data);
}
/**
* @deprecated not used; to be removed in future releases.
*
* Wraps a ByteBuffer in an InputStream.
*
* @param byteBuffer The ByteBuffer to wrap.
*
* @return An InputStream wrapping the ByteBuffer content.
*/
@Deprecated
public static ByteArrayInputStream toStream(ByteBuffer byteBuffer) {
if (byteBuffer == null) {
return null;
}
return new ByteArrayInputStream(copyBytesFrom(byteBuffer));
}
/**
* Returns a copy of all the bytes from the given ByteBuffer,
* from the beginning to the buffer's limit; or null if the input is null.
*
* The internal states of the given byte buffer will be restored when this
* method completes execution.
*
* When handling ByteBuffer from user's input, it's typical to
* call the {@link #copyBytesFrom(java.nio.ByteBuffer)} instead of
* {@link #copyAllBytesFrom(java.nio.ByteBuffer)} so as to account for the position
* of the input ByteBuffer. The opposite is typically true,
* however, when handling ByteBuffer from withint the
* unmarshallers of the low-level clients.
*/
public static byte[] copyAllBytesFrom(ByteBuffer bb) {
if (bb == null)
return null;
if (bb.hasArray())
return Arrays.copyOf(bb.array(), bb.limit());
bb.mark();
// the default ByteBuffer#mark() and reset() won't work, as the
// rewind would discard the mark position
final int marked = bb.position();
try {
byte[] dst = new byte[bb.rewind().remaining()];
bb.get(dst);
return dst;
} finally {
bb.position(marked);
}
}
/**
* Returns a copy of the bytes from the given ByteBuffer,
* ranging from the the buffer's current position to the buffer's limit; or
* null if the input is null.
*
* The internal states of the given byte buffer will be restored when this
* method completes execution.
*
* When handling ByteBuffer from user's input, it's typical to
* call the {@link #copyBytesFrom(java.nio.ByteBuffer)} instead of
* {@link #copyAllBytesFrom(java.nio.ByteBuffer)} so as to account for the position
* of the input ByteBuffer. The opposite is typically true,
* however, when handling ByteBuffer from withint the
* unmarshallers of the low-level clients.
*/
public static byte[] copyBytesFrom(ByteBuffer bb) {
if (bb == null)
return null;
if (bb.hasArray())
return Arrays.copyOfRange(bb.array(), bb.position(), bb.limit());
bb.mark();
try {
byte[] dst = new byte[bb.remaining()];
bb.get(dst);
return dst;
} finally {
bb.reset();
}
}
}