| /* |
| * 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.github.javaparser.utils; |
| |
| import java.io.IOException; |
| import java.io.StringWriter; |
| import java.io.Writer; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| |
| /** |
| * Adapted from apache commons-lang3 project. |
| * <p> |
| * Unescapes escaped chars in strings. |
| */ |
| public class StringEscapeUtils { |
| |
| private StringEscapeUtils() { |
| } |
| |
| /** |
| * <p>Escapes the characters in a {@code String} using Java String rules.</p> |
| * <p> |
| * <p>Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.) </p> |
| * <p> |
| * <p>So a tab becomes the characters {@code '\\'} and |
| * {@code 't'}.</p> |
| * <p> |
| * <p>The only difference between Java strings and JavaScript strings |
| * is that in JavaScript, a single quote and forward-slash (/) are escaped.</p> |
| * <p> |
| * <p>Example:</p> |
| * <pre> |
| * input string: He didn't say, "Stop!" |
| * output string: He didn't say, \"Stop!\" |
| * </pre> |
| * |
| * @param input String to escape values in, may be null |
| * @return String with escaped values, {@code null} if null string input |
| */ |
| public static String escapeJava(final String input) { |
| return ESCAPE_JAVA.translate(input); |
| } |
| |
| /** |
| * <p>Unescapes any Java literals found in the {@code String}. |
| * For example, it will turn a sequence of {@code '\'} and |
| * {@code 'n'} into a newline character, unless the {@code '\'} |
| * is preceded by another {@code '\'}.</p> |
| * |
| * @param input the {@code String} to unescape, may be null |
| * @return a new unescaped {@code String}, {@code null} if null string input |
| */ |
| public static String unescapeJava(final String input) { |
| return UNESCAPE_JAVA.translate(input); |
| } |
| |
| private static final String[][] JAVA_CTRL_CHARS_UNESCAPE = { |
| {"\\b", "\b"}, |
| {"\\n", "\n"}, |
| {"\\t", "\t"}, |
| {"\\f", "\f"}, |
| {"\\r", "\r"} |
| }; |
| |
| private static final String[][] JAVA_CTRL_CHARS_ESCAPE = { |
| {"\b", "\\b"}, |
| {"\n", "\\n"}, |
| {"\t", "\\t"}, |
| {"\f", "\\f"}, |
| {"\r", "\\r"} |
| }; |
| |
| private static final CharSequenceTranslator ESCAPE_JAVA = |
| new AggregateTranslator( |
| new LookupTranslator( |
| new String[][]{ |
| {"\"", "\\\""}, |
| {"\\", "\\\\"}, |
| }), |
| new LookupTranslator(JAVA_CTRL_CHARS_ESCAPE.clone()) |
| ); |
| |
| private static final CharSequenceTranslator UNESCAPE_JAVA = |
| new AggregateTranslator( |
| new OctalUnescaper(), |
| new UnicodeUnescaper(), |
| new LookupTranslator(JAVA_CTRL_CHARS_UNESCAPE.clone()), |
| new LookupTranslator( |
| new String[][]{ |
| {"\\\\", "\\"}, |
| {"\\\"", "\""}, |
| {"\\'", "'"}, |
| {"\\", ""} |
| }) |
| ); |
| |
| /** |
| * Adapted from apache commons-lang3 project. |
| * <p> |
| * An API for translating text. |
| * Its core use is to escape and unescape text. Because escaping and unescaping |
| * is completely contextual, the API does not present two separate signatures. |
| * |
| * @since 3.0 |
| */ |
| private static abstract class CharSequenceTranslator { |
| |
| /** |
| * Translate a set of codepoints, represented by an int index into a CharSequence, |
| * into another set of codepoints. The number of codepoints consumed must be returned, |
| * and the only IOExceptions thrown must be from interacting with the Writer so that |
| * the top level API may reliably ignore StringWriter IOExceptions. |
| * |
| * @param input CharSequence that is being translated |
| * @param index int representing the current point of translation |
| * @param out Writer to translate the text to |
| * @return int count of codepoints consumed |
| * @throws IOException if and only if the Writer produces an IOException |
| */ |
| public abstract int translate(CharSequence input, int index, Writer out) throws IOException; |
| |
| /** |
| * Helper for non-Writer usage. |
| * |
| * @param input CharSequence to be translated |
| * @return String output of translation |
| */ |
| public final String translate(final CharSequence input) { |
| if (input == null) { |
| return null; |
| } |
| try { |
| final StringWriter writer = new StringWriter(input.length() * 2); |
| translate(input, writer); |
| return writer.toString(); |
| } catch (final IOException ioe) { |
| // this should never ever happen while writing to a StringWriter |
| throw new RuntimeException(ioe); |
| } |
| } |
| |
| /** |
| * Translate an input onto a Writer. This is intentionally final as its algorithm is |
| * tightly coupled with the abstract method of this class. |
| * |
| * @param input CharSequence that is being translated |
| * @param out Writer to translate the text to |
| * @throws IOException if and only if the Writer produces an IOException |
| */ |
| public final void translate(final CharSequence input, final Writer out) throws IOException { |
| if (out == null) { |
| throw new IllegalArgumentException("The Writer must not be null"); |
| } |
| if (input == null) { |
| return; |
| } |
| int pos = 0; |
| final int len = input.length(); |
| while (pos < len) { |
| final int consumed = translate(input, pos, out); |
| if (consumed == 0) { |
| // inlined implementation of Character.toChars(Character.codePointAt(input, pos)) |
| // avoids allocating temp char arrays and duplicate checks |
| char c1 = input.charAt(pos); |
| out.write(c1); |
| pos++; |
| if (Character.isHighSurrogate(c1) && pos < len) { |
| char c2 = input.charAt(pos); |
| if (Character.isLowSurrogate(c2)) { |
| out.write(c2); |
| pos++; |
| } |
| } |
| continue; |
| } |
| // contract with translators is that they have to understand codepoints |
| // and they just took care of a surrogate pair |
| for (int pt = 0; pt < consumed; pt++) { |
| pos += Character.charCount(Character.codePointAt(input, pos)); |
| } |
| } |
| } |
| |
| /** |
| * Helper method to create a merger of this translator with another set of |
| * translators. Useful in customizing the standard functionality. |
| * |
| * @param translators CharSequenceTranslator array of translators to merge with this one |
| * @return CharSequenceTranslator merging this translator with the others |
| */ |
| public final CharSequenceTranslator with(final CharSequenceTranslator... translators) { |
| final CharSequenceTranslator[] newArray = new CharSequenceTranslator[translators.length + 1]; |
| newArray[0] = this; |
| System.arraycopy(translators, 0, newArray, 1, translators.length); |
| return new AggregateTranslator(newArray); |
| } |
| |
| } |
| |
| /** |
| * Adapted from apache commons-lang3 project. |
| * <p> |
| * Translates a value using a lookup table. |
| * |
| * @since 3.0 |
| */ |
| private static class LookupTranslator extends CharSequenceTranslator { |
| |
| private final HashMap<String, String> lookupMap; |
| private final HashSet<Character> prefixSet; |
| private final int shortest; |
| private final int longest; |
| |
| /** |
| * Define the lookup table to be used in translation |
| * <p> |
| * Note that, as of Lang 3.1, the key to the lookup table is converted to a |
| * java.lang.String. This is because we need the key to support hashCode and |
| * equals(Object), allowing it to be the key for a HashMap. See LANG-882. |
| * |
| * @param lookup CharSequence[][] table of size [*][2] |
| */ |
| public LookupTranslator(final CharSequence[]... lookup) { |
| lookupMap = new HashMap<>(); |
| prefixSet = new HashSet<>(); |
| int _shortest = Integer.MAX_VALUE; |
| int _longest = 0; |
| if (lookup != null) { |
| for (final CharSequence[] seq : lookup) { |
| this.lookupMap.put(seq[0].toString(), seq[1].toString()); |
| this.prefixSet.add(seq[0].charAt(0)); |
| final int sz = seq[0].length(); |
| if (sz < _shortest) { |
| _shortest = sz; |
| } |
| if (sz > _longest) { |
| _longest = sz; |
| } |
| } |
| } |
| shortest = _shortest; |
| longest = _longest; |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public int translate(final CharSequence input, final int index, final Writer out) throws IOException { |
| // check if translation exists for the input at position index |
| if (prefixSet.contains(input.charAt(index))) { |
| int max = longest; |
| if (index + longest > input.length()) { |
| max = input.length() - index; |
| } |
| // implement greedy algorithm by trying maximum match first |
| for (int i = max; i >= shortest; i--) { |
| final CharSequence subSeq = input.subSequence(index, index + i); |
| final String result = lookupMap.get(subSeq.toString()); |
| |
| if (result != null) { |
| out.write(result); |
| return i; |
| } |
| } |
| } |
| return 0; |
| } |
| } |
| |
| /** |
| * Adapted from apache commons-lang3 project. |
| * <p> |
| * Executes a sequence of translators one after the other. Execution ends whenever |
| * the first translator consumes codepoints from the input. |
| * |
| * @since 3.0 |
| */ |
| private static class AggregateTranslator extends CharSequenceTranslator { |
| |
| private final CharSequenceTranslator[] translators; |
| |
| /** |
| * Specify the translators to be used at creation time. |
| * |
| * @param translators CharSequenceTranslator array to aggregate |
| */ |
| public AggregateTranslator(final CharSequenceTranslator... translators) { |
| this.translators = translators == null ? null : translators.clone(); |
| } |
| |
| /** |
| * The first translator to consume codepoints from the input is the 'winner'. |
| * Execution stops with the number of consumed codepoints being returned. |
| * {@inheritDoc} |
| */ |
| @Override |
| public int translate(final CharSequence input, final int index, final Writer out) throws IOException { |
| for (final CharSequenceTranslator translator : translators) { |
| final int consumed = translator.translate(input, index, out); |
| if (consumed != 0) { |
| return consumed; |
| } |
| } |
| return 0; |
| } |
| |
| } |
| |
| /** |
| * Adapted from apache commons-lang3 project. |
| * <p> |
| * Translate escaped octal Strings back to their octal values. |
| * <p> |
| * For example, "\45" should go back to being the specific value (a %). |
| * <p> |
| * Note that this currently only supports the viable range of octal for Java; namely |
| * 1 to 377. This is because parsing Java is the main use case. |
| * |
| * @since 3.0 |
| */ |
| private static class OctalUnescaper extends CharSequenceTranslator { |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public int translate(final CharSequence input, final int index, final Writer out) throws IOException { |
| final int remaining = input.length() - index - 1; // how many characters left, ignoring the first \ |
| final StringBuilder builder = new StringBuilder(); |
| if (input.charAt(index) == '\\' && remaining > 0 && isOctalDigit(input.charAt(index + 1))) { |
| final int next = index + 1; |
| final int next2 = index + 2; |
| final int next3 = index + 3; |
| |
| // we know this is good as we checked it in the if block above |
| builder.append(input.charAt(next)); |
| |
| if (remaining > 1 && isOctalDigit(input.charAt(next2))) { |
| builder.append(input.charAt(next2)); |
| if (remaining > 2 && isZeroToThree(input.charAt(next)) && isOctalDigit(input.charAt(next3))) { |
| builder.append(input.charAt(next3)); |
| } |
| } |
| |
| out.write(Integer.parseInt(builder.toString(), 8)); |
| return 1 + builder.length(); |
| } |
| return 0; |
| } |
| |
| /** |
| * Checks if the given char is an octal digit. Octal digits are the character representations of the digits 0 to |
| * 7. |
| * |
| * @param ch the char to check |
| * @return true if the given char is the character representation of one of the digits from 0 to 7 |
| */ |
| private boolean isOctalDigit(final char ch) { |
| return ch >= '0' && ch <= '7'; |
| } |
| |
| /** |
| * Checks if the given char is the character representation of one of the digit from 0 to 3. |
| * |
| * @param ch the char to check |
| * @return true if the given char is the character representation of one of the digits from 0 to 3 |
| */ |
| private boolean isZeroToThree(final char ch) { |
| return ch >= '0' && ch <= '3'; |
| } |
| } |
| |
| /** |
| * Adapted from apache commons-lang3 project. |
| * <p> |
| * Translates escaped Unicode values of the form \\u+\d\d\d\d back to |
| * Unicode. It supports multiple 'u' characters and will work with or |
| * without the +. |
| * |
| * @since 3.0 |
| */ |
| private static class UnicodeUnescaper extends CharSequenceTranslator { |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public int translate(final CharSequence input, final int index, final Writer out) throws IOException { |
| if (input.charAt(index) == '\\' && index + 1 < input.length() && input.charAt(index + 1) == 'u') { |
| // consume optional additional 'u' chars |
| int i = 2; |
| while (index + i < input.length() && input.charAt(index + i) == 'u') { |
| i++; |
| } |
| |
| if (index + i < input.length() && input.charAt(index + i) == '+') { |
| i++; |
| } |
| |
| if (index + i + 4 <= input.length()) { |
| // Get 4 hex digits |
| final CharSequence unicode = input.subSequence(index + i, index + i + 4); |
| |
| try { |
| final int value = Integer.parseInt(unicode.toString(), 16); |
| out.write((char) value); |
| } catch (final NumberFormatException nfe) { |
| throw new IllegalArgumentException("Unable to parse unicode value: " + unicode, nfe); |
| } |
| return i + 4; |
| } |
| throw new IllegalArgumentException("Less than 4 hex digits in unicode value: '" + input.subSequence(index, input.length()) |
| + "' due to end of CharSequence"); |
| } |
| return 0; |
| } |
| } |
| |
| } |