com.gitee.starblues.loader.jar.AsciiBytes Maven / Gradle / Ivy
/*
* Copyright 2012-2021 the original author or authors.
* Copy from spring-boot-loader
*
* 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
*
* https://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.gitee.starblues.loader.jar;
import java.nio.charset.StandardCharsets;
/**
* 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
*/
public class AsciiBytes {
private static final String EMPTY_STRING = "";
private static final int[] INITIAL_BYTE_BITMASK = { 0x7F, 0x1F, 0x0F, 0x07 };
private static final int SUBSEQUENT_BYTE_BITMASK = 0x3F;
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
*/
AsciiBytes(String string) {
this(string.getBytes(StandardCharsets.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
*/
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
*/
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;
}
int length() {
return this.length;
}
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;
}
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;
}
AsciiBytes substring(int beginIndex) {
return substring(beginIndex, this.length);
}
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);
}
boolean matches(CharSequence name, char suffix) {
int charIndex = 0;
int nameLen = name.length();
int totalLen = nameLen + ((suffix != 0) ? 1 : 0);
for (int i = this.offset; i < this.offset + this.length; i++) {
int b = this.bytes[i];
int remainingUtfBytes = getNumberOfUtfBytes(b) - 1;
b &= INITIAL_BYTE_BITMASK[remainingUtfBytes];
for (int j = 0; j < remainingUtfBytes; j++) {
b = (b << 6) + (this.bytes[++i] & SUBSEQUENT_BYTE_BITMASK);
}
char c = getChar(name, suffix, charIndex++);
if (b <= 0xFFFF) {
if (c != b) {
return false;
}
} else {
if (c != ((b >> 0xA) + 0xD7C0)) {
return false;
}
c = getChar(name, suffix, charIndex++);
if (c != ((b & 0x3FF) + 0xDC00)) {
return false;
}
}
}
return charIndex == totalLen;
}
private char getChar(CharSequence name, char suffix, int index) {
if (index < name.length()) {
return name.charAt(index);
}
if (index == name.length()) {
return suffix;
}
return 0;
}
private int getNumberOfUtfBytes(int b) {
if ((b & 0x80) == 0) {
return 1;
}
int numberOfUtfBytes = 0;
while ((b & 0x80) != 0) {
b <<= 1;
numberOfUtfBytes++;
}
return numberOfUtfBytes;
}
@Override
public boolean equals(Object obj) {
if (obj == null) {
return false;
}
if (this == obj) {
return true;
}
if (obj.getClass() == 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;
}
@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];
int remainingUtfBytes = getNumberOfUtfBytes(b) - 1;
b &= INITIAL_BYTE_BITMASK[remainingUtfBytes];
for (int j = 0; j < remainingUtfBytes; j++) {
b = (b << 6) + (this.bytes[++i] & SUBSEQUENT_BYTE_BITMASK);
}
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 String toString() {
if (this.string == null) {
if (this.length == 0) {
this.string = EMPTY_STRING;
} else {
this.string = new String(this.bytes, this.offset, this.length, StandardCharsets.UTF_8);
}
}
return this.string;
}
static String toString(byte[] bytes) {
return new String(bytes, StandardCharsets.UTF_8);
}
static int hashCode(CharSequence charSequence) {
// We're compatible with String's hashCode()
if (charSequence instanceof StringSequence) {
// ... but save making an unnecessary String for StringSequence
return charSequence.hashCode();
}
return charSequence.toString().hashCode();
}
static int hashCode(int hash, char suffix) {
return (suffix != 0) ? (31 * hash + suffix) : hash;
}
}