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RePlay is a fork of the Play1 framework, created by Codeborne.
There is a newer version: 2.6.2
package play.mvc;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/** Provides operations around the encoding and decoding of Cookie data. */
public class CookieDataCodec {

  /**
   * Cookie session parser for cookie created by version 1.2.5 or before.
   *
   * We need it to support old Play 1.2.5 session data encoding so that the cookie data doesn't
   * become invalid when applications are upgraded to a newer version of Play
   */
  public static Pattern oldCookieSessionParser =
      Pattern.compile("\u0000([^:]*):([^\u0000]*)\u0000");

  /**
   * @param map the map to decode data into.
   * @param data the data to decode.
   * @throws UnsupportedEncodingException if the encoding is not supported
   */
  public static void decode(Map map, String data)
      throws UnsupportedEncodingException {
    // support old Play 1.2.5 session data encoding so that the cookie data doesn't become invalid when
    // applications are upgraded to a newer version of Play
    if (data.startsWith("%00") && data.contains("%3A") && data.endsWith("%00")) {
      String sessionData = URLDecoder.decode(data, StandardCharsets.UTF_8);
      Matcher matcher = oldCookieSessionParser.matcher(sessionData);
      while (matcher.find()) {
        map.put(matcher.group(1), matcher.group(2));
      }
      return;
    }

    String[] keyValues = data.split("&");
    for (String keyValue : keyValues) {
      String[] split = keyValue.split("=", 2);
      if (split.length == 2) {
        map.put(
            URLDecoder.decode(split[0], StandardCharsets.UTF_8),
            URLDecoder.decode(split[1], StandardCharsets.UTF_8));
      }
    }
  }

  /**
   * @param map the data to encode.
   * @return the encoded data.
   * @throws UnsupportedEncodingException if the encoding is not supported
   */
  public static String encode(Map map) throws UnsupportedEncodingException {
    StringBuilder data = new StringBuilder();
    String separator = "";
    for (Map.Entry entry : map.entrySet()) {
      if (entry.getValue() != null) {
        data.append(separator)
            .append(URLEncoder.encode(entry.getKey(), StandardCharsets.UTF_8))
            .append("=")
            .append(URLEncoder.encode(entry.getValue(), StandardCharsets.UTF_8));
        separator = "&";
      }
    }
    return data.toString();
  }

  /**
   * Constant time for same length String comparison, to prevent timing attacks
   *
   * @param a The string a
   * @param b the string b
   * @return true is the 2 strings are equals
   */
  public static boolean safeEquals(String a, String b) {
    if (a.length() != b.length()) {
      return false;
    } else {
      char equal = 0;
      for (int i = 0; i < a.length(); i++) {
        equal |= a.charAt(i) ^ b.charAt(i);
      }
      return equal == 0;
    }
  }
}