content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.onegravity.rteditor.converter.tagsoup.util;
  
  import java.io.IOException;
  import java.io.StringWriter;
  import java.io.Writer;
  import java.util.Locale;
  
  /**
   * An API for translating text.
   * Its core use is to escape and unescape text. Because escaping and unescaping
   * is completely contextual, the API does not present two separate signatures.
   *
   * @version $Id: CharSequenceTranslator.java 1568612 2014-02-15 10:35:35Z britter $
   * @since 3.0
   */
  public abstract class CharSequenceTranslator {
  
      /**
       * Translate a set of codepoints, represented by an int index into a CharSequence,
       * into another set of codepoints. The number of codepoints consumed must be returned,
       * and the only IOExceptions thrown must be from interacting with the Writer so that
       * the top level API may reliably ignore StringWriter IOExceptions.
       *
       * @param input CharSequence that is being translated
       * @param index int representing the current point of translation
       * @param out   Writer to translate the text to
       * @return int count of codepoints consumed
       * @throws IOException if and only if the Writer produces an IOException
       */
      public abstract int translate(CharSequence input, int index, Writer out) throws IOException;
  
      /**
       * Helper for non-Writer usage.
       *
       * @param input CharSequence to be translated
       * @return String output of translation
       */
      public final String translate(final CharSequence input) {
          if (input == null) {
              return null;
          }
          try {
              final StringWriter writer = new StringWriter(input.length() * 2);
              translate(input, writer);
              return writer.toString();
          } catch (final IOException ioe) {
              // this should never ever happen while writing to a StringWriter
              throw new RuntimeException(ioe);
          }
      }
  
      /**
       * Translate an input onto a Writer. This is intentionally final as its algorithm is
       * tightly coupled with the abstract method of this class.
       *
       * @param input CharSequence that is being translated
       * @param out   Writer to translate the text to
       * @throws IOException if and only if the Writer produces an IOException
       */
      public final void translate(final CharSequence input, final Writer out) throws IOException {
          if (out == null) {
              throw new IllegalArgumentException("The Writer must not be null");
          }
          if (input == null) {
              return;
          }
          int pos = 0;
          final int len = input.length();
          while (pos < len) {
              final int consumed = translate(input, pos, out);
              if (consumed == 0) {
                  final char[] c = Character.toChars(Character.codePointAt(input, pos));
                  out.write(c);
                  pos += c.length;
                  continue;
              }
              // contract with translators is that they have to understand codepoints
              // and they just took care of a surrogate pair
              for (int pt = 0; pt < consumed; pt++) {
                  pos += Character.charCount(Character.codePointAt(input, pos));
              }
          }
      }
  
      /**
       * Helper method to create a merger of this translator with another set of
       * translators. Useful in customizing the standard functionality.
       *
       * @param translators CharSequenceTranslator array of translators to merge with this one
       * @return CharSequenceTranslator merging this translator with the others
       */
      public final CharSequenceTranslator with(final CharSequenceTranslator... translators) {
          final CharSequenceTranslator[] newArray = new CharSequenceTranslator[translators.length + 1];
          newArray[0] = this;
          System.arraycopy(translators, 0, newArray, 1, translators.length);
          return new AggregateTranslator(newArray);
      }
  
      /**
       * <p>Returns an upper case hexadecimal <code>String</code> for the given
       * character.</p>
       *
       * @param codepoint The codepoint to convert.
       * @return An upper case hexadecimal <code>String</code>
       */
      public static String hex(final int codepoint) {
          return Integer.toHexString(codepoint).toUpperCase(Locale.ENGLISH);
      }
  
  }
  