content: /*
   * Copyright (c) 2013. wyouflf (wyouflf@gmail.com)
   *
   * 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.
   */
  
  package com.lidroid.xutils.http.client.util;
  
  import android.text.TextUtils;
  import org.apache.http.Header;
  import org.apache.http.HeaderElement;
  import org.apache.http.HttpEntity;
  import org.apache.http.NameValuePair;
  import org.apache.http.message.BasicHeaderValueParser;
  import org.apache.http.message.BasicNameValuePair;
  import org.apache.http.message.ParserCursor;
  import org.apache.http.protocol.HTTP;
  import org.apache.http.util.CharArrayBuffer;
  
  import java.net.URI;
  import java.nio.ByteBuffer;
  import java.nio.CharBuffer;
  import java.nio.charset.Charset;
  import java.util.*;
  
  /**
   * A collection of utilities for encoding URLs.
   *
   * @since 4.0
   */
  public class URLEncodedUtils {
  
      public static final String CONTENT_TYPE = "application/x-www-form-urlencoded";
      private static final String PARAMETER_SEPARATOR = "&";
      private static final String NAME_VALUE_SEPARATOR = "=";
  
      /**
       * Returns true if the entity's Content-Type header is
       * <code>application/x-www-form-urlencoded</code>.
       */
      public static boolean isEncoded(final HttpEntity entity) {
          Header h = entity.getContentType();
          if (h != null) {
              HeaderElement[] elems = h.getElements();
              if (elems.length > 0) {
                  String contentType = elems[0].getName();
                  return contentType.equalsIgnoreCase(CONTENT_TYPE);
              } else {
                  return false;
              }
          } else {
              return false;
          }
      }
  
      /**
       * Returns a list of {@link org.apache.http.NameValuePair NameValuePairs} as built from the
       * URI's query portion. For example, a URI of
       * http://example.org/path/to/file?a=1&b=2&c=3 would return a list of three
       * NameValuePairs, one for a=1, one for b=2, and one for c=3.
       * <p/>
       * This is typically useful while parsing an HTTP PUT.
       *
       * @param uri uri to parse
       */
      public static List<NameValuePair> parse(final URI uri) {
          final String query = uri.getRawQuery();
          if (!TextUtils.isEmpty(query)) {
              List<NameValuePair> result = new ArrayList<NameValuePair>();
              Scanner scanner = new Scanner(query);
              parse(result, scanner);
              return result;
          } else {
              return Collections.emptyList();
          }
      }
  
      /**
       * Adds all parameters within the Scanner to the list of <code>parameters</code>.
       * For example,a scanner containing the string <code>a=1&b=2&c=3</code> would
       * add the {@link org.apache.http.NameValuePair NameValuePairs} a=1, b=2, and c=3 to the
       * list of parameters.
       *
       * @param parameters List to add parameters to.
       * @param scanner    Input that contains the parameters to parse.
       */
      public static void parse(
              final List<NameValuePair> parameters,
              final Scanner scanner) {
          scanner.useDelimiter(PARAMETER_SEPARATOR);
          while (scanner.hasNext()) {
              String name = null;
              String value = null;
              String token = scanner.next();
              int i = token.indexOf(NAME_VALUE_SEPARATOR);
              if (i != -1) {
                  name = token.substring(0, i).trim();
                  value = token.substring(i + 1).trim();
              } else {
                  name = token.trim();
              }
              parameters.add(new BasicNameValuePair(name, value));
          }
      }
  
      private static final char[] DELIM = new char[]{'&'};
  
      /**
       * Returns a list of {@link org.apache.http.NameValuePair NameValuePairs} as parsed.
       *
       * @param s text to parse.
       * @since 4.2
       */
      public static List<NameValuePair> parse(final String s) {
          if (s == null) {
              return Collections.emptyList();
          }
          BasicHeaderValueParser parser = BasicHeaderValueParser.DEFAULT;
          CharArrayBuffer buffer = new CharArrayBuffer(s.length());
          buffer.append(s);
          ParserCursor cursor = new ParserCursor(0, buffer.length());
          List<NameValuePair> list = new ArrayList<NameValuePair>();
          while (!cursor.atEnd()) {
              NameValuePair nvp = parser.parseNameValuePair(buffer, cursor, DELIM);
              if (nvp.getName().length() > 0) {
                  list.add(new BasicNameValuePair(nvp.getName(), nvp.getValue()));
              }
          }
          return list;
      }
  
      /**
       * Returns a String that is suitable for use as an <code>application/x-www-form-urlencoded</code>
       * list of parameters in an HTTP PUT or HTTP POST.
       *
       * @param parameters The parameters to include.
       * @param charset    The encoding to use.
       */
      public static String format(
              final List<? extends NameValuePair> parameters,
              final String charset) {
          final StringBuilder result = new StringBuilder();
          for (final NameValuePair parameter : parameters) {
              final String encodedName = encodeFormFields(parameter.getName(), charset);
              final String encodedValue = encodeFormFields(parameter.getValue(), charset);
              if (result.length() > 0) {
                  result.append(PARAMETER_SEPARATOR);
              }
              result.append(encodedName);
              if (encodedValue != null) {
                  result.append(NAME_VALUE_SEPARATOR);
                  result.append(encodedValue);
              }
          }
          return result.toString();
      }
  
      /**
       * Returns a String that is suitable for use as an <code>application/x-www-form-urlencoded</code>
       * list of parameters in an HTTP PUT or HTTP POST.
       *
       * @param parameters The parameters to include.
       * @param charset    The encoding to use.
       * @since 4.2
       */
      public static String format(
              final Iterable<? extends NameValuePair> parameters,
              final Charset charset) {
          final StringBuilder result = new StringBuilder();
          for (final NameValuePair parameter : parameters) {
              final String encodedName = encodeFormFields(parameter.getName(), charset);
              final String encodedValue = encodeFormFields(parameter.getValue(), charset);
              if (result.length() > 0) {
                  result.append(PARAMETER_SEPARATOR);
              }
              result.append(encodedName);
              if (encodedValue != null) {
                  result.append(NAME_VALUE_SEPARATOR);
                  result.append(encodedValue);
              }
          }
          return result.toString();
      }
  
      /**
       * Unreserved characters, i.e. alphanumeric, plus: {@code _ - ! . ~ ' ( ) *}
       * <p/>
       * This list is the same as the {@code unreserved} list in
       * <a href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>
       */
      private static final BitSet UNRESERVED = new BitSet(256);
      /**
       * Punctuation characters: , ; : $ & + =
       * <p/>
       * These are the additional characters allowed by userinfo.
       */
      private static final BitSet PUNCT = new BitSet(256);
      /**
       * Characters which are safe to use in userinfo, i.e. {@link #UNRESERVED} plus {@link #PUNCT}uation
       */
      private static final BitSet USERINFO = new BitSet(256);
      /**
       * Characters which are safe to use in a path, i.e. {@link #UNRESERVED} plus {@link #PUNCT}uation plus / @
       */
      private static final BitSet PATHSAFE = new BitSet(256);
      /**
       * Characters which are safe to use in a fragment, i.e. {@link #RESERVED} plus {@link #UNRESERVED}
       */
      private static final BitSet FRAGMENT = new BitSet(256);
  
      /**
       * Reserved characters, i.e. {@code ;/?:@&=+$,[]}
       * <p/>
       * This list is the same as the {@code reserved} list in
       * <a href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>
       * as augmented by
       * <a href="http://www.ietf.org/rfc/rfc2732.txt">RFC 2732</a>
       */
      private static final BitSet RESERVED = new BitSet(256);
  
  
      /**
       * Safe characters for x-www-form-urlencoded data, as per java.net.URLEncoder and browser behaviour,
       * i.e. alphanumeric plus {@code "-", "_", ".", "*"}
       */
      private static final BitSet URLENCODER = new BitSet(256);
  
      static {
          // unreserved chars
          // alpha characters
          for (int i = 'a'; i <= 'z'; i++) {
              UNRESERVED.set(i);
          }
          for (int i = 'A'; i <= 'Z'; i++) {
              UNRESERVED.set(i);
          }
          // numeric characters
          for (int i = '0'; i <= '9'; i++) {
              UNRESERVED.set(i);
          }
          UNRESERVED.set('_'); // these are the charactes of the "mark" list
          UNRESERVED.set('-');
          UNRESERVED.set('.');
          UNRESERVED.set('*');
          URLENCODER.or(UNRESERVED); // skip remaining unreserved characters
          UNRESERVED.set('!');
          UNRESERVED.set('~');
          UNRESERVED.set('\'');
          UNRESERVED.set('(');
          UNRESERVED.set(')');
          // punct chars
          PUNCT.set(',');
          PUNCT.set(';');
          PUNCT.set(':');
          PUNCT.set('$');
          PUNCT.set('&');
          PUNCT.set('+');
          PUNCT.set('=');
          // Safe for userinfo
          USERINFO.or(UNRESERVED);
          USERINFO.or(PUNCT);
  
          // URL path safe
          PATHSAFE.or(UNRESERVED);
          PATHSAFE.set('/'); // segment separator
          PATHSAFE.set(';'); // param separator
          PATHSAFE.set(':'); // rest as per list in 2396, i.e. : @ & = + $ ,
          PATHSAFE.set('@');
          PATHSAFE.set('&');
          PATHSAFE.set('=');
          PATHSAFE.set('+');
          PATHSAFE.set('$');
          PATHSAFE.set(',');
  
          RESERVED.set(';');
          RESERVED.set('/');
          RESERVED.set('?');
          RESERVED.set(':');
          RESERVED.set('@');
          RESERVED.set('&');
          RESERVED.set('=');
          RESERVED.set('+');
          RESERVED.set('$');
          RESERVED.set(',');
          RESERVED.set('['); // added by RFC 2732
          RESERVED.set(']'); // added by RFC 2732
  
          FRAGMENT.or(RESERVED);
          FRAGMENT.or(UNRESERVED);
      }
  
      private static final int RADIX = 16;
  
      private static String urlencode(
              final String content,
              final Charset charset,
              final BitSet safechars,
              final boolean blankAsPlus) {
          if (content == null) {
              return null;
          }
          StringBuilder buf = new StringBuilder();
          ByteBuffer bb = charset.encode(content);
          while (bb.hasRemaining()) {
              int b = bb.get() & 0xff;
              if (safechars.get(b)) {
                  buf.append((char) b);
              } else if (blankAsPlus && b == ' ') {
                  buf.append('+');
              } else {
                  buf.append("%");
                  char hex1 = Character.toUpperCase(Character.forDigit((b >> 4) & 0xF, RADIX));
                  char hex2 = Character.toUpperCase(Character.forDigit(b & 0xF, RADIX));
                  buf.append(hex1);
                  buf.append(hex2);
              }
          }
          return buf.toString();
      }
  
      /**
       * Decode/unescape a portion of a URL, to use with the query part ensure {@code plusAsBlank} is true.
       *
       * @param content     the portion to decode
       * @param charset     the charset to use
       * @param plusAsBlank if {@code true}, then convert '+' to space (e.g. for www-url-form-encoded content), otherwise leave as is.
       * @return encoded string
       */
      private static String urldecode(
              final String content,
              final Charset charset,
              final boolean plusAsBlank) {
          if (content == null) {
              return null;
          }
          ByteBuffer bb = ByteBuffer.allocate(content.length());
          CharBuffer cb = CharBuffer.wrap(content);
          while (cb.hasRemaining()) {
              char c = cb.get();
              if (c == '%' && cb.remaining() >= 2) {
                  char uc = cb.get();
                  char lc = cb.get();
                  int u = Character.digit(uc, 16);
                  int l = Character.digit(lc, 16);
                  if (u != -1 && l != -1) {
                      bb.put((byte) ((u << 4) + l));
                  } else {
                      bb.put((byte) '%');
                      bb.put((byte) uc);
                      bb.put((byte) lc);
                  }
              } else if (plusAsBlank && c == '+') {
                  bb.put((byte) ' ');
              } else {
                  bb.put((byte) c);
              }
          }
          bb.flip();
          return charset.decode(bb).toString();
      }
  
      /**
       * Decode/unescape www-url-form-encoded content.
       *
       * @param content the content to decode, will decode '+' as space
       * @param charset the charset to use
       * @return encoded string
       */
      private static String decodeFormFields(final String content, final String charset) {
          if (content == null) {
              return null;
          }
          return urldecode(content, charset != null ? Charset.forName(charset) : Charset.forName(HTTP.UTF_8), true);
      }
  
      /**
       * Decode/unescape www-url-form-encoded content.
       *
       * @param content the content to decode, will decode '+' as space
       * @param charset the charset to use
       * @return encoded string
       */
      private static String decodeFormFields(final String content, final Charset charset) {
          if (content == null) {
              return null;
          }
          return urldecode(content, charset != null ? charset : Charset.forName(HTTP.UTF_8), true);
      }
  
      /**
       * Encode/escape www-url-form-encoded content.
       * <p/>
       * Uses the {@link #URLENCODER} set of characters, rather than
       * the set; this is for compatibilty with previous
       * releases, URLEncoder.encode() and most browsers.
       *
       * @param content the content to encode, will convert space to '+'
       * @param charset the charset to use
       * @return encoded string
       */
      private static String encodeFormFields(final String content, final String charset) {
          if (content == null) {
              return null;
          }
          return urlencode(content, charset != null ? Charset.forName(charset) :
                  Charset.forName(HTTP.UTF_8), URLENCODER, true);
      }
  
      /**
       * Encode/escape www-url-form-encoded content.
       * <p/>
       * Uses the {@link #URLENCODER} set of characters, rather than
       * the set; this is for compatibilty with previous
       * releases, URLEncoder.encode() and most browsers.
       *
       * @param content the content to encode, will convert space to '+'
       * @param charset the charset to use
       * @return encoded string
       */
      private static String encodeFormFields(final String content, final Charset charset) {
          if (content == null) {
              return null;
          }
          return urlencode(content, charset != null ? charset : Charset.forName(HTTP.UTF_8), URLENCODER, true);
      }
  
      /**
       * Encode a String using the {@link #USERINFO} set of characters.
       * <p/>
       * Used by URIBuilder to encode the userinfo segment.
       *
       * @param content the string to encode, does not convert space to '+'
       * @param charset the charset to use
       * @return the encoded string
       */
      static String encUserInfo(final String content, final Charset charset) {
          return urlencode(content, charset, USERINFO, false);
      }
  
      /**
       * Encode a String using the {@link #FRAGMENT} set of characters.
       * <p/>
       * Used by URIBuilder to encode the userinfo segment.
       *
       * @param content the string to encode, does not convert space to '+'
       * @param charset the charset to use
       * @return the encoded string
       */
      static String encFragment(final String content, final Charset charset) {
          return urlencode(content, charset, FRAGMENT, false);
      }
  
      /**
       * Encode a String using the {@link #PATHSAFE} set of characters.
       * <p/>
       * Used by URIBuilder to encode path segments.
       *
       * @param content the string to encode, does not convert space to '+'
       * @param charset the charset to use
       * @return the encoded string
       */
      static String encPath(final String content, final Charset charset) {
          return urlencode(content, charset, PATHSAFE, false);
      }
  
  }
  