com.alipay.sofa.ark.loader.jar.AsciiBytes 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 com.alipay.sofa.ark.loader.jar;
import java.nio.charset.Charset;
/**
* Simple wrapper around a byte array that represents an ASCII. Used for performance
* reasons to save constructing Strings for ZIP data.
*
* @author Phillip Webb
* @author Andy Wilkinson
*/
final public class AsciiBytes {
private static final Charset UTF_8 = Charset.forName("UTF-8");
private final byte[] bytes;
private final int offset;
private final int length;
private String string;
private int hash;
/**
* Create a new {@link AsciiBytes} from the specified String.
* @param string the source string
*/
public AsciiBytes(String string) {
this(string.getBytes(UTF_8));
this.string = string;
}
/**
* Create a new {@link AsciiBytes} from the specified bytes. NOTE: underlying bytes
* are not expected to change.
* @param bytes the source bytes
*/
public AsciiBytes(byte[] bytes) {
this(bytes, 0, bytes.length);
}
/**
* Create a new {@link AsciiBytes} from the specified bytes. NOTE: underlying bytes
* are not expected to change.
* @param bytes the source bytes
* @param offset the offset
* @param length the length
*/
public AsciiBytes(byte[] bytes, int offset, int length) {
if (offset < 0 || length < 0 || (offset + length) > bytes.length) {
throw new IndexOutOfBoundsException();
}
this.bytes = bytes;
this.offset = offset;
this.length = length;
}
public int length() {
return this.length;
}
public boolean startsWith(AsciiBytes prefix) {
if (this == prefix) {
return true;
}
if (prefix.length > this.length) {
return false;
}
for (int i = 0; i < prefix.length; i++) {
if (this.bytes[i + this.offset] != prefix.bytes[i + prefix.offset]) {
return false;
}
}
return true;
}
public boolean endsWith(AsciiBytes postfix) {
if (this == postfix) {
return true;
}
if (postfix.length > this.length) {
return false;
}
for (int i = 0; i < postfix.length; i++) {
if (this.bytes[this.offset + (this.length - 1) - i] != postfix.bytes[postfix.offset
+ (postfix.length - 1)
- i]) {
return false;
}
}
return true;
}
public AsciiBytes substring(int beginIndex) {
return substring(beginIndex, this.length);
}
public AsciiBytes substring(int beginIndex, int endIndex) {
int length = endIndex - beginIndex;
if (this.offset + length > this.bytes.length) {
throw new IndexOutOfBoundsException();
}
return new AsciiBytes(this.bytes, this.offset + beginIndex, length);
}
public AsciiBytes append(String string) {
if (string == null || string.isEmpty()) {
return this;
}
return append(string.getBytes(UTF_8));
}
public AsciiBytes append(AsciiBytes asciiBytes) {
if (asciiBytes == null || asciiBytes.length() == 0) {
return this;
}
return append(asciiBytes.bytes);
}
public AsciiBytes append(byte[] bytes) {
if (bytes == null || bytes.length == 0) {
return this;
}
byte[] combined = new byte[this.length + bytes.length];
System.arraycopy(this.bytes, this.offset, combined, 0, this.length);
System.arraycopy(bytes, 0, combined, this.length, bytes.length);
return new AsciiBytes(combined);
}
@Override
public String toString() {
if (this.string == null) {
this.string = new String(this.bytes, this.offset, this.length, UTF_8);
}
return this.string;
}
@Override
public int hashCode() {
int hash = this.hash;
if (hash == 0 && this.bytes.length > 0) {
for (int i = this.offset; i < this.offset + this.length; i++) {
int b = this.bytes[i];
if (b < 0) {
b = b & 0x7F;
int limit;
int excess = 0x80;
if (b < 96) {
limit = 1;
excess += 0x40 << 6;
} else if (b < 112) {
limit = 2;
excess += (0x60 << 12) + (0x80 << 6);
} else {
limit = 3;
excess += (0x70 << 18) + (0x80 << 12) + (0x80 << 6);
}
for (int j = 0; j < limit; j++) {
b = (b << 6) + (this.bytes[++i] & 0xFF);
}
b -= excess;
}
if (b <= 0xFFFF) {
hash = 31 * hash + b;
} else {
hash = 31 * hash + ((b >> 0xA) + 0xD7C0);
hash = 31 * hash + ((b & 0x3FF) + 0xDC00);
}
}
this.hash = hash;
}
return hash;
}
@Override
public boolean equals(Object obj) {
if (obj == null) {
return false;
}
if (this == obj) {
return true;
}
if (obj.getClass().equals(AsciiBytes.class)) {
AsciiBytes other = (AsciiBytes) obj;
if (this.length == other.length) {
for (int i = 0; i < this.length; i++) {
if (this.bytes[this.offset + i] != other.bytes[other.offset + i]) {
return false;
}
}
return true;
}
}
return false;
}
static String toString(byte[] bytes) {
return new String(bytes, UTF_8);
}
public static int hashCode(String string) {
// We're compatible with String's hashCode().
return string.hashCode();
}
public static int hashCode(int hash, String string) {
for (int i = 0; i < string.length(); i++) {
hash = 31 * hash + string.charAt(i);
}
return hash;
}
}