Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright (C) 2014 The Android Open Source 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.
 */

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    private static final Pattern ESCAPED_CHARACTER_PATTERN = Pattern.compile("%([A-Fa-f0-9]{2})");

    /**
     * Unescapes an escaped file or directory name back to its original value.
     *
     * <p>See {@link #escapeFileName(String)} for more information.
     *
     * @param fileName File name to be unescaped.
     * @return The original value of the file name before it was escaped,
     *    or null if the escaped fileName seems invalid.
     */
    public static String unescapeFileName(String fileName) {
        int length = fileName.length();
        int percentCharacterCount = 0;
        for (int i = 0; i < length; i++) {
            if (fileName.charAt(i) == '%') {
                percentCharacterCount++;
            }
        }
        if (percentCharacterCount == 0) {
            return fileName;
        }

        int expectedLength = length - percentCharacterCount * 2;
        StringBuilder builder = new StringBuilder(expectedLength);
        Matcher matcher = ESCAPED_CHARACTER_PATTERN.matcher(fileName);
        int endOfLastMatch = 0;
        while (percentCharacterCount > 0 && matcher.find()) {
            char unescapedCharacter = (char) Integer.parseInt(matcher.group(1), 16);
            builder.append(fileName, endOfLastMatch, matcher.start()).append(unescapedCharacter);
            endOfLastMatch = matcher.end();
            percentCharacterCount--;
        }
        if (endOfLastMatch < length) {
            builder.append(fileName, endOfLastMatch, length);
        }
        if (builder.length() != expectedLength) {
            return null;
        }
        return builder.toString();
    }
}