content: /*
   * Copyright (c) 2019 abc123lzf <abc123lzf@126.com>
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  package com.lzf.flyingsocks.client.pac;
  
  import org.apache.commons.lang3.StringUtils;
  
  import java.io.BufferedReader;
  import java.io.FileReader;
  import java.io.FileWriter;
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * @author lzf abc123lzf@126.com
   * @since 2021/3/2 6:24
   */
  public class IPv4Downloader {
  
      private static final Map<String, Integer> MASK_CACHE = new HashMap<>();
  
      static {
          int c = 1;
          int v = 0;
          for (int i = 0; i < 32; i++) {
              int mask = c << i;
              MASK_CACHE.put(Long.toString(mask), 32 - v);
              v++;
          }
      }
  
      public static void main(String[] args) throws IOException {
          BufferedReader reader = new BufferedReader(new FileReader(args[0]));
          FileWriter writer = new FileWriter(args[1]);
  
          String line;
          while ((line = reader.readLine()) != null) {
              if (line.startsWith("#")) {
                  continue;
              }
  
              String[] arr = StringUtils.split(line, '|');
              if (!arr[1].equals("CN") || !arr[2].equals("ipv4")) {
                  continue;
              }
  
              String ip = arr[3];
              String mask = arr[4];
  
              writer.write(ip + "/" + MASK_CACHE.get(mask));
              writer.write('\n');
          }
  
          writer.close();
          reader.close();
      }
  
  
  
  
  }
  