org.apache.mina.core.buffer.IoBufferHexDumper Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.mina.core.buffer;
/**
* Provides utility methods to dump an {@link IoBuffer} into a hex formatted
* string.
*
* @author Apache MINA Project
*/
class IoBufferHexDumper {
/**
* The high digits lookup table.
*/
private static final byte[] highDigits;
/**
* The low digits lookup table.
*/
private static final byte[] lowDigits;
/**
* Initialize lookup tables.
*/
static {
final byte[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
int i;
byte[] high = new byte[256];
byte[] low = new byte[256];
for (i = 0; i < 256; i++) {
high[i] = digits[i >>> 4];
low[i] = digits[i & 0x0F];
}
highDigits = high;
lowDigits = low;
}
/**
* Dumps an {@link IoBuffer} to a hex formatted string.
*
* @param in the buffer to dump
* @param lengthLimit the limit at which hex dumping will stop
* @return a hex formatted string representation of the in {@link IoBuffer}.
*/
public static String getHexdump(IoBuffer in, int lengthLimit) {
if (lengthLimit == 0) {
throw new IllegalArgumentException("lengthLimit: " + lengthLimit + " (expected: 1+)");
}
int limit = in.limit();
int pos = in.position();
boolean truncate = limit - pos > lengthLimit;
int size;
if (truncate) {
size = lengthLimit;
} else {
size = limit - pos;
}
if (size == 0) {
return "empty";
}
StringBuilder out = new StringBuilder(size * 3 + 3);
// fill the first
int byteValue = in.get(pos++) & 0xFF;
out.append((char) highDigits[byteValue]);
out.append((char) lowDigits[byteValue]);
// and the others, too
for (; pos < limit; ) {
out.append(' ');
byteValue = in.get(pos++) & 0xFF;
out.append((char) highDigits[byteValue]);
out.append((char) lowDigits[byteValue]);
}
if (truncate) {
out.append("...");
}
return out.toString();
}
}