com.phloc.web.encoding.RFC5987Encoder Maven / Gradle / Ivy

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/**
 * Copyright (C) 2006-2015 phloc systems
 * http://www.phloc.com
 * office[at]phloc[dot]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.phloc.web.encoding;

import java.nio.charset.Charset;
import java.util.Arrays;

import javax.annotation.Nonnull;

import com.phloc.commons.ValueEnforcer;
import com.phloc.commons.charset.CCharset;
import com.phloc.commons.charset.CharsetManager;
import com.phloc.commons.encode.IEncoder;
import com.phloc.commons.string.StringHelper;

/**
 * RFC 5987 Encoder
 * 
 * @author Philip Helger
 */
public class RFC5987Encoder implements IEncoder 
{
  public static final char ESCAPE_CHAR = '%';
  // Order is important for binary search!
  private static final byte [] ALLOWED_BYTES = { '!',
                                                '#',
                                                '$',
                                                '&',
                                                '+',
                                                '-',
                                                '.',
                                                '0',
                                                '1',
                                                '2',
                                                '3',
                                                '4',
                                                '5',
                                                '6',
                                                '7',
                                                '8',
                                                '9',
                                                'A',
                                                'B',
                                                'C',
                                                'D',
                                                'E',
                                                'F',
                                                'G',
                                                'H',
                                                'I',
                                                'J',
                                                'K',
                                                'L',
                                                'M',
                                                'N',
                                                'O',
                                                'P',
                                                'Q',
                                                'R',
                                                'S',
                                                'T',
                                                'U',
                                                'V',
                                                'W',
                                                'X',
                                                'Y',
                                                'Z',
                                                '^',
                                                '_',
                                                '`',
                                                'a',
                                                'b',
                                                'c',
                                                'd',
                                                'e',
                                                'f',
                                                'g',
                                                'h',
                                                'i',
                                                'j',
                                                'k',
                                                'l',
                                                'm',
                                                'n',
                                                'o',
                                                'p',
                                                'q',
                                                'r',
                                                's',
                                                't',
                                                'u',
                                                'v',
                                                'w',
                                                'x',
                                                'y',
                                                'z',
                                                '|',
                                                '~' };
  private final Charset m_aCharset;

  public RFC5987Encoder ()
  {
    this (CCharset.CHARSET_UTF_8_OBJ);
  }

  public RFC5987Encoder (@Nonnull final Charset aCharset)
  {
    m_aCharset = ValueEnforcer.notNull (aCharset, "Charset");
  }

  @Nonnull
  public static String getRFC5987Encoded (@Nonnull final String sSrc, @Nonnull final Charset aCharset)
  {
    ValueEnforcer.notNull (sSrc, "Src");

    final StringBuilder aSB = new StringBuilder (sSrc.length () * 2);
    for (final byte b : CharsetManager.getAsBytes (sSrc, aCharset))
    {
      if (Arrays.binarySearch (ALLOWED_BYTES, b) >= 0)
        aSB.append ((char) b);
      else
      {
        aSB.append (ESCAPE_CHAR)
           .append (StringHelper.getHexChar ((b >> 4) & 0xf))
           .append (StringHelper.getHexChar (b & 0xf));
      }
    }

    return aSB.toString ();
  }

  @Nonnull
  public static String getRFC5987EncodedUTF8 (@Nonnull final String sSrc)
  {
    return getRFC5987Encoded (sSrc, CCharset.CHARSET_UTF_8_OBJ);
  }

  @Nonnull
  public String encode (@Nonnull final String sSrc)
  {
    return getRFC5987Encoded (sSrc, m_aCharset);
  }
}