com.aspectran.web.support.util.HtmlCharacterEntityDecoder Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2023 The Aspectran Project
*
* 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.aspectran.web.support.util;
/**
* This class is a clone of org.springframework.web.util.HtmlCharacterEntityDecoder
*
* Helper for decoding HTML Strings by replacing character
* entity references with the referred character.
*/
class HtmlCharacterEntityDecoder {
private static final int MAX_REFERENCE_SIZE = 10;
private final HtmlCharacterEntityReferences characterEntityReferences;
private final String originalMessage;
private final StringBuilder decodedMessage;
private int currentPosition = 0;
private int nextPotentialReferencePosition = -1;
private int nextSemicolonPosition = -2;
public HtmlCharacterEntityDecoder(HtmlCharacterEntityReferences characterEntityReferences, String original) {
this.characterEntityReferences = characterEntityReferences;
this.originalMessage = original;
this.decodedMessage = new StringBuilder(original.length());
}
public String decode() {
while (this.currentPosition < this.originalMessage.length()) {
findNextPotentialReference(this.currentPosition);
copyCharactersTillPotentialReference();
processPossibleReference();
}
return this.decodedMessage.toString();
}
private void findNextPotentialReference(int startPosition) {
this.nextPotentialReferencePosition = Math.max(startPosition, this.nextSemicolonPosition - MAX_REFERENCE_SIZE);
do {
this.nextPotentialReferencePosition =
this.originalMessage.indexOf('&', this.nextPotentialReferencePosition);
if (this.nextSemicolonPosition != -1 &&
this.nextSemicolonPosition < this.nextPotentialReferencePosition) {
this.nextSemicolonPosition = this.originalMessage.indexOf(';', this.nextPotentialReferencePosition + 1);
}
boolean isPotentialReference = (this.nextPotentialReferencePosition != -1 &&
this.nextSemicolonPosition != -1 &&
this.nextPotentialReferencePosition - this.nextSemicolonPosition < MAX_REFERENCE_SIZE);
if (isPotentialReference) {
break;
}
if (this.nextPotentialReferencePosition == -1) {
break;
}
if (this.nextSemicolonPosition == -1) {
this.nextPotentialReferencePosition = -1;
break;
}
this.nextPotentialReferencePosition = this.nextPotentialReferencePosition + 1;
}
while (this.nextPotentialReferencePosition != -1);
}
private void copyCharactersTillPotentialReference() {
if (this.nextPotentialReferencePosition != this.currentPosition) {
int skipUntilIndex = (this.nextPotentialReferencePosition != -1 ?
this.nextPotentialReferencePosition : this.originalMessage.length());
if (skipUntilIndex - this.currentPosition > 3) {
this.decodedMessage.append(this.originalMessage, this.currentPosition, skipUntilIndex);
this.currentPosition = skipUntilIndex;
}
else {
while (this.currentPosition < skipUntilIndex) {
this.decodedMessage.append(this.originalMessage.charAt(this.currentPosition++));
}
}
}
}
private void processPossibleReference() {
if (this.nextPotentialReferencePosition != -1) {
boolean isNumberedReference = (this.originalMessage.charAt(this.currentPosition + 1) == '#');
boolean wasProcessable = isNumberedReference ? processNumberedReference() : processNamedReference();
if (wasProcessable) {
this.currentPosition = this.nextSemicolonPosition + 1;
}
else {
char currentChar = this.originalMessage.charAt(this.currentPosition);
this.decodedMessage.append(currentChar);
this.currentPosition++;
}
}
}
private boolean processNumberedReference() {
char referenceChar = this.originalMessage.charAt(this.nextPotentialReferencePosition + 2);
boolean isHexNumberedReference = (referenceChar == 'x' || referenceChar == 'X');
try {
int value = (!isHexNumberedReference ?
Integer.parseInt(getReferenceSubstring(2)) :
Integer.parseInt(getReferenceSubstring(3), 16));
this.decodedMessage.append((char) value);
return true;
}
catch (NumberFormatException ex) {
return false;
}
}
private boolean processNamedReference() {
String referenceName = getReferenceSubstring(1);
char mappedCharacter = this.characterEntityReferences.convertToCharacter(referenceName);
if (mappedCharacter != HtmlCharacterEntityReferences.CHAR_NULL) {
this.decodedMessage.append(mappedCharacter);
return true;
}
return false;
}
private String getReferenceSubstring(int referenceOffset) {
return this.originalMessage.substring(
this.nextPotentialReferencePosition + referenceOffset, this.nextSemicolonPosition);
}
}