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/*
* Copyright 2010-2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Portions copyright 2006-2009 James Murty. Please see LICENSE.txt
* for applicable license terms and NOTICE.txt for applicable notices.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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.amazonaws.util;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.Arrays;
/**
* Utilities for encoding and decoding binary data to and from different forms.
*/
public class BinaryUtils {
private static final int HEX_LENGTH_8 = 8;
private static final int HEX_PARSE_16 = 16;
private static final int FF_LOCATION = 6;
/**
* Converts byte data to a Hex-encoded string.
*
* @param data data to hex encode.
* @return hex-encoded string.
*/
public static String toHex(byte[] data) {
final StringBuilder sb = new StringBuilder(data.length * 2);
for (int i = 0; i < data.length; i++) {
String hex = Integer.toHexString(data[i]);
if (hex.length() == 1) {
// Append leading zero.
sb.append("0");
} else if (hex.length() == HEX_LENGTH_8) {
// Remove ff prefix from negative numbers.
hex = hex.substring(FF_LOCATION);
}
sb.append(hex);
}
return StringUtils.lowerCase(sb.toString());
}
/**
* 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) {
final 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, HEX_PARSE_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);
}
/**
* Wraps a ByteBuffer in an InputStream.
*
* @param byteBuffer The ByteBuffer to wrap.
* @return An InputStream wrapping the ByteBuffer content.
*/
public static InputStream toStream(ByteBuffer byteBuffer) {
final byte[] bytes = new byte[byteBuffer.remaining()];
byteBuffer.get(bytes);
return new ByteArrayInputStream(bytes);
}
/**
* @param bb the byte buffer.
* @return 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(ByteBuffer)} instead of
* {@link #copyAllBytesFrom(ByteBuffer)} so as to account for the position
* of the input ByteBuffer. The opposite is typically true,
* however, when handling ByteBuffer from within the
* unmarshallers of the low-level clients.
*/
public static byte[] copyAllBytesFrom(ByteBuffer bb) {
if (bb == null) {
return null;
}
if (bb.hasArray()) {
return Arrays.copyOfRange(
bb.array(),
bb.arrayOffset(),
bb.arrayOffset() + bb.limit());
}
final ByteBuffer copy = bb.asReadOnlyBuffer();
copy.rewind();
final byte[] dst = new byte[copy.remaining()];
copy.get(dst);
return dst;
}
}