/*
* Copyright 2012 The Netty Project
*
* The Netty Project 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 io.netty.util.internal;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Formatter;
import java.util.List;
/**
* String utility class.
*/
public final class StringUtil {
public static final String NEWLINE;
private static final String[] BYTE2HEX_PAD = new String[256];
private static final String[] BYTE2HEX_NOPAD = new String[256];
private static final String EMPTY_STRING = "";
static {
// Determine the newline character of the current platform.
String newLine;
try {
newLine = new Formatter().format("%n").toString();
} catch (Exception e) {
// Should not reach here, but just in case.
newLine = "\n";
}
NEWLINE = newLine;
// Generate the lookup table that converts a byte into a 2-digit hexadecimal integer.
int i;
for (i = 0; i < 10; i ++) {
StringBuilder buf = new StringBuilder(2);
buf.append('0');
buf.append(i);
BYTE2HEX_PAD[i] = buf.toString();
BYTE2HEX_NOPAD[i] = String.valueOf(i);
}
for (; i < 16; i ++) {
StringBuilder buf = new StringBuilder(2);
char c = (char) ('a' + i - 10);
buf.append('0');
buf.append(c);
BYTE2HEX_PAD[i] = buf.toString();
BYTE2HEX_NOPAD[i] = String.valueOf(c);
}
for (; i < BYTE2HEX_PAD.length; i ++) {
StringBuilder buf = new StringBuilder(2);
buf.append(Integer.toHexString(i));
String str = buf.toString();
BYTE2HEX_PAD[i] = str;
BYTE2HEX_NOPAD[i] = str;
}
}
/**
* Splits the specified {@link String} with the specified delimiter. This operation is a simplified and optimized
* version of {@link String#split(String)}.
*/
public static String[] split(String value, char delim) {
final int end = value.length();
final List<String> res = new ArrayList<String>();
int start = 0;
for (int i = 0; i < end; i ++) {
if (value.charAt(i) == delim) {
if (start == i) {
res.add(EMPTY_STRING);
} else {
res.add(value.substring(start, i));
}
start = i + 1;
}
}
if (start == 0) { // If no delimiter was found in the value
res.add(value);
} else {
if (start != end) {
// Add the last element if it's not empty.
res.add(value.substring(start, end));
} else {
// Truncate trailing empty elements.
for (int i = res.size() - 1; i >= 0; i --) {
if (res.get(i).isEmpty()) {
res.remove(i);
} else {
break;
}
}
}
}
return res.toArray(new String[res.size()]);
}
/**
* Splits the specified {@link String} with the specified delimiter in maxParts maximum parts.
* This operation is a simplified and optimized
* version of {@link String#split(String, int)}.
*/
public static String[] split(String value, char delim, int maxParts) {
final int end = value.length();
final List<String> res = new ArrayList<String>();
int start = 0;
int cpt = 1;
for (int i = 0; i < end && cpt < maxParts; i ++) {
if (value.charAt(i) == delim) {
if (start == i) {
res.add(EMPTY_STRING);
} else {
res.add(value.substring(start, i));
}
start = i + 1;
cpt++;
}
}
if (start == 0) { // If no delimiter was found in the value
res.add(value);
} else {
if (start != end) {
// Add the last element if it's not empty.
res.add(value.substring(start, end));
} else {
// Truncate trailing empty elements.
for (int i = res.size() - 1; i >= 0; i --) {
if (res.get(i).isEmpty()) {
res.remove(i);
} else {
break;
}
}
}
}
return res.toArray(new String[res.size()]);
}
/**
* Get the item after one char delim if the delim is found (else null).
* This operation is a simplified and optimized
* version of {@link String#split(String, int)}.
*/
public static String substringAfter(String value, char delim) {
int pos = value.indexOf(delim);
if (pos >= 0) {
return value.substring(pos + 1);
}
return null;
}
/**
* Converts the specified byte value into a 2-digit hexadecimal integer.
*/
public static String byteToHexStringPadded(int value) {
return BYTE2HEX_PAD[value & 0xff];
}
/**
* Converts the specified byte value into a 2-digit hexadecimal integer and appends it to the specified buffer.
*/
public static <T extends Appendable> T byteToHexStringPadded(T buf, int value) {
try {
buf.append(byteToHexStringPadded(value));
} catch (IOException e) {
PlatformDependent.throwException(e);
}
return buf;
}
/**
* Converts the specified byte array into a hexadecimal value.
*/
public static String toHexStringPadded(byte[] src) {
return toHexStringPadded(src, 0, src.length);
}
/**
* Converts the specified byte array into a hexadecimal value.
*/
public static String toHexStringPadded(byte[] src, int offset, int length) {
return toHexStringPadded(new StringBuilder(length << 1), src, offset, length).toString();
}
/**
* Converts the specified byte array into a hexadecimal value and appends it to the specified buffer.
*/
public static <T extends Appendable> T toHexStringPadded(T dst, byte[] src) {
return toHexStringPadded(dst, src, 0, src.length);
}
/**
* Converts the specified byte array into a hexadecimal value and appends it to the specified buffer.
*/
public static <T extends Appendable> T toHexStringPadded(T dst, byte[] src, int offset, int length) {
final int end = offset + length;
for (int i = offset; i < end; i ++) {
byteToHexStringPadded(dst, src[i]);
}
return dst;
}
/**
* Converts the specified byte value into a hexadecimal integer.
*/
public static String byteToHexString(int value) {
return BYTE2HEX_NOPAD[value & 0xff];
}
/**
* Converts the specified byte value into a hexadecimal integer and appends it to the specified buffer.
*/
public static <T extends Appendable> T byteToHexString(T buf, int value) {
try {
buf.append(byteToHexString(value));
} catch (IOException e) {
PlatformDependent.throwException(e);
}
return buf;
}
/**
* Converts the specified byte array into a hexadecimal value.
*/
public static String toHexString(byte[] src) {
return toHexString(src, 0, src.length);
}
/**
* Converts the specified byte array into a hexadecimal value.
*/
public static String toHexString(byte[] src, int offset, int length) {
return toHexString(new StringBuilder(length << 1), src, offset, length).toString();
}
/**
* Converts the specified byte array into a hexadecimal value and appends it to the specified buffer.
*/
public static <T extends Appendable> T toHexString(T dst, byte[] src) {
return toHexString(dst, src, 0, src.length);
}
/**
* Converts the specified byte array into a hexadecimal value and appends it to the specified buffer.
*/
public static <T extends Appendable> T toHexString(T dst, byte[] src, int offset, int length) {
assert length >= 0;
if (length == 0) {
return dst;
}
final int end = offset + length;
final int endMinusOne = end - 1;
int i;
// Skip preceding zeroes.
for (i = offset; i < endMinusOne; i ++) {
if (src[i] != 0) {
break;
}
}
byteToHexString(dst, src[i ++]);
int remaining = end - i;
toHexStringPadded(dst, src, i, remaining);
return dst;
}
/**
* The shortcut to {@link #simpleClassName(Class) simpleClassName(o.getClass())}.
*/
public static String simpleClassName(Object o) {
if (o == null) {
return "null_object";
} else {
return simpleClassName(o.getClass());
}
}
/**
* Generates a simplified name from a {@link Class}. Similar to {@link Class#getSimpleName()}, but it works fine
* with anonymous classes.
*/
public static String simpleClassName(Class<?> clazz) {
if (clazz == null) {
return "null_class";
}
Package pkg = clazz.getPackage();
if (pkg != null) {
return clazz.getName().substring(pkg.getName().length() + 1);
} else {
return clazz.getName();
}
}
private StringUtil() {
// Unused.
}
}