com.github.robtimus.io.stream.HexOutputStream Maven / Gradle / Ivy
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/*
* HexOutputStream.java
* Copyright 2020 Rob Spoor
*
* 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.github.robtimus.io.stream;
import static com.github.robtimus.io.stream.StreamUtils.checkOffsetAndLength;
import static com.github.robtimus.io.stream.StreamUtils.checkStartAndEnd;
import static com.github.robtimus.io.stream.StreamUtils.streamClosedException;
import static org.apache.commons.io.IOUtils.writer;
import java.io.Closeable;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
/**
* An output stream that converts bytes into hex.
*
* When a hex output stream is closed, its wrapped {@link Appendable} will be closed as well if it implements {@link Closeable} or
* {@link AutoCloseable}.
*
* @author Rob Spoor
*/
public final class HexOutputStream extends OutputStream {
private static final int WRITE_BUFFER_SIZE = 1024;
private Writer output;
private final boolean upperCase;
private char[] writeBuffer;
/**
* Creates a new hex output stream. It will write hex in lower case.
*
* @param destination The appendable to write to.
* @throws NullPointerException If the given appendable is {@code null}.
*/
public HexOutputStream(Appendable destination) {
this(destination, false);
}
/**
* Creates a new hex output stream.
*
* @param destination The appendable to write to.
* @param upperCase {@code true} to write hex in upper case, or {@code false} to write hex in lower case.
* @throws NullPointerException If the given appendable is {@code null}.
*/
public HexOutputStream(Appendable destination, boolean upperCase) {
this.output = writer(destination);
this.upperCase = upperCase;
}
private void ensureOpen() throws IOException {
if (output == null) {
throw streamClosedException();
}
}
@Override
public void write(int b) throws IOException {
ensureOpen();
if (writeBuffer == null) {
writeBuffer = new char[WRITE_BUFFER_SIZE];
}
writeBuffer[0] = high(b, upperCase);
writeBuffer[1] = low(b, upperCase);
output.write(writeBuffer, 0, 2);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
ensureOpen();
checkOffsetAndLength(b, off, len);
char[] cbuf;
int lenInHex = len * 2;
if (lenInHex <= WRITE_BUFFER_SIZE) {
if (writeBuffer == null) {
writeBuffer = new char[WRITE_BUFFER_SIZE];
}
cbuf = writeBuffer;
} else {
// Don't permanently allocate very large buffers.
cbuf = new char[lenInHex];
}
for (int i = off, j = 0, k = 0; j < len; i++, j++, k += 2) {
cbuf[k] = high(b[i], upperCase);
cbuf[k + 1] = low(b[i], upperCase);
}
output.write(cbuf, 0, lenInHex);
}
@Override
public void flush() throws IOException {
ensureOpen();
output.flush();
}
@Override
public void close() throws IOException {
if (output != null) {
output.close();
output = null;
}
}
/**
* Converts a byte array to its lower case hex representation.
*
* @param b The byte array to convert.
* @return The hex representation of the given byte array.
* @throws NullPointerException If the given byte array is {@code null}.
*/
public static String encode(byte[] b) {
return encode(b, 0, b.length);
}
/**
* Converts a portion of byte array to its lower case hex representation.
*
* @param b The byte array to convert a portion of.
* @param start The start index of the portion to convert, inclusive.
* @param end The end index of the portion to convert, exclusive.
* @return The hex representation of the given portion of the given byte array.
* @throws NullPointerException If the given byte array is {@code null}.
* @throws IndexOutOfBoundsException If the given start index is negative, the given end index is larger than the given array's length,
* or the given start index is larger than the given end index.
*/
public static String encode(byte[] b, int start, int end) {
return encode(b, start, end, false);
}
/**
* Converts a byte array to its hex representation.
*
* @param b The byte array to convert.
* @param upperCase {@code true} to return hex in upper case, or {@code false} to return hex in lower case.
* @return The hex representation of the given byte array.
* @throws NullPointerException If the given byte array is {@code null}.
*/
public static String encode(byte[] b, boolean upperCase) {
return encode(b, 0, b.length, upperCase);
}
/**
* Converts a portion of a byte array to its hex representation.
*
* @param b The byte array to convert a portion of.
* @param start The start index of the portion to convert, inclusive.
* @param end The end index of the portion to convert, exclusive.
* @param upperCase {@code true} to return hex in upper case, or {@code false} to return hex in lower case.
* @return The hex representation of the given portion of the given byte array.
* @throws NullPointerException If the given byte array is {@code null}.
* @throws IndexOutOfBoundsException If the given start index is negative, the given end index is larger than the given array's length,
* or the given start index is larger than the given end index.
*/
public static String encode(byte[] b, int start, int end, boolean upperCase) {
checkStartAndEnd(b, start, end);
char[] c = new char[(end - start) * 2];
for (int i = start, j = 0; i < end; i++, j += 2) {
c[j] = high(b[i], upperCase);
c[j + 1] = low(b[i], upperCase);
}
return new String(c);
}
private static char high(int b, boolean upperCase) {
int high = (b >> 4) & 0xF;
char c = Character.forDigit(high, 16);
return upperCase ? Character.toUpperCase(c) : Character.toLowerCase(c);
}
private static char low(int b, boolean upperCase) {
int low = b & 0xF;
char c = Character.forDigit(low, 16);
return upperCase ? Character.toUpperCase(c) : Character.toLowerCase(c);
}
}