org.sonar.javascript.checks.EscapeUtils Maven / Gradle / Ivy
/*
* SonarQube JavaScript Plugin
* Copyright (C) 2011-2023 SonarSource SA
* mailto:info AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.sonar.javascript.checks;
public final class EscapeUtils {
private EscapeUtils() {}
public static String unescape(String value) {
StringBuilder result = new StringBuilder();
StringBuilder escapeSequence = new StringBuilder(4);
int i = 0;
while (i < value.length()) {
char ch = value.charAt(i);
if (ch == '\\') {
i++;
ch = value.charAt(i);
if (ch == 'u') {
i = consumeEscapeSequence(i, 4, value, escapeSequence, result);
} else if (ch == 'x') {
i = consumeEscapeSequence(i, 2, value, escapeSequence, result);
} else {
result.append(unescape(ch));
i++;
}
} else {
result.append(ch);
i++;
}
}
return result.toString();
}
private static int consumeEscapeSequence(
int i,
int len,
String value,
StringBuilder escapeSequence,
StringBuilder result
) {
int ii = i;
while (escapeSequence.length() != len && ii < value.length()) {
ii++;
escapeSequence.append(value.charAt(ii));
}
if (escapeSequence.length() == len) {
result.append((char) Integer.parseInt(escapeSequence.toString(), 16));
escapeSequence.setLength(0);
}
ii++;
return ii;
}
private static char unescape(char ch) {
final char result;
switch (ch) {
case 'b':
result = '\b';
break;
case 't':
result = '\t';
break;
case 'n':
result = '\n';
break;
case 'v':
result = '\u000B';
break;
case 'f':
result = '\f';
break;
case 'r':
result = '\r';
break;
case '\"':
result = '"';
break;
case '\'':
result = '\'';
break;
case '\\':
result = '\\';
break;
default:
result = ch;
break;
}
return result;
}
}