content: /*
   * Copyright (C) 2006 The Android Open Source Project
   *
   * 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 android.text.method;
  
  import android.graphics.Rect;
  import android.text.Editable;
  import android.text.GetChars;
  import android.text.Spannable;
  import android.text.Spanned;
  import android.text.SpannedString;
  import android.text.TextUtils;
  import android.view.View; 
  
  /**
   * This transformation method causes the characters in the {@link #getOriginal}
   * array to be replaced by the corresponding characters in the
   * {@link #getReplacement} array.
   */
  public abstract class ReplacementTransformationMethod
  implements TransformationMethod
  {
      /**
       * Returns the list of characters that are to be replaced by other
       * characters when displayed.
       */
      protected abstract char[] getOriginal();
      /**
       * Returns a parallel array of replacement characters for the ones
       * that are to be replaced.
       */
      protected abstract char[] getReplacement();
  
      /**
       * Returns a CharSequence that will mirror the contents of the
       * source CharSequence but with the characters in {@link #getOriginal}
       * replaced by ones from {@link #getReplacement}.
       */
      public CharSequence getTransformation(CharSequence source, View v) {
          char[] original = getOriginal();
          char[] replacement = getReplacement();
  
          /*
           * Short circuit for faster display if the text will never change.
           */
          if (!(source instanceof Editable)) {
              /*
               * Check whether the text does not contain any of the
               * source characters so can be used unchanged.
               */
              boolean doNothing = true;
              int n = original.length;
              for (int i = 0; i < n; i++) {
                  if (TextUtils.indexOf(source, original[i]) >= 0) {
                      doNothing = false;
                      break;
                  }
              }
              if (doNothing) {
                  return source;
              }
  
              if (!(source instanceof Spannable)) {
                  /*
                   * The text contains some of the source characters,
                   * but they can be flattened out now instead of
                   * at display time.
                   */
                  if (source instanceof Spanned) {
                      return new SpannedString(new SpannedReplacementCharSequence(
                                                          (Spanned) source,
                                                          original, replacement));
                  } else {
                      return new ReplacementCharSequence(source,
                                                         original,
                                                         replacement).toString();
                  }
              }
          }
  
          if (source instanceof Spanned) {
              return new SpannedReplacementCharSequence((Spanned) source,
                                                        original, replacement);
          } else {
              return new ReplacementCharSequence(source, original, replacement);
          }
      }
  
      public void onFocusChanged(View view, CharSequence sourceText,
                                 boolean focused, int direction,
                                 Rect previouslyFocusedRect) {
          // This callback isn't used.
      }
  
      private static class ReplacementCharSequence
      implements CharSequence, GetChars {
          private char[] mOriginal, mReplacement;
  
          public ReplacementCharSequence(CharSequence source, char[] original,
                                         char[] replacement) {
              mSource = source;
              mOriginal = original;
              mReplacement = replacement;
          }
  
          public int length() {
              return mSource.length();
          }
  
          public char charAt(int i) {
              char c = mSource.charAt(i);
  
              int n = mOriginal.length;
              for (int j = 0; j < n; j++) {
                  if (c == mOriginal[j]) {
                      c = mReplacement[j];
                  }
              }
  
              return c;
          }
  
          public CharSequence subSequence(int start, int end) {
              char[] c = new char[end - start];
  
              getChars(start, end, c, 0);
              return new String(c);
          }
  
          public String toString() {
              char[] c = new char[length()];
  
              getChars(0, length(), c, 0);
              return new String(c);
          }
  
          public void getChars(int start, int end, char[] dest, int off) {
              TextUtils.getChars(mSource, start, end, dest, off);
              int offend = end - start + off;
              int n = mOriginal.length;
  
              for (int i = off; i < offend; i++) {
                  char c = dest[i];
  
                  for (int j = 0; j < n; j++) {
                      if (c == mOriginal[j]) {
                          dest[i] = mReplacement[j];
                      }
                  }
              }
          }
  
          private CharSequence mSource;
      }
  
      private static class SpannedReplacementCharSequence
      extends ReplacementCharSequence
      implements Spanned
      {
          public SpannedReplacementCharSequence(Spanned source, char[] original,
                                                char[] replacement) {
              super(source, original, replacement);
              mSpanned = source;
          }
  
          public CharSequence subSequence(int start, int end) {
              return new SpannedString(this).subSequence(start, end);
          }
  
          public <T> T[] getSpans(int start, int end, Class<T> type) {
              return mSpanned.getSpans(start, end, type);
          }
  
          public int getSpanStart(Object tag) {
              return mSpanned.getSpanStart(tag);
          }
  
          public int getSpanEnd(Object tag) {
              return mSpanned.getSpanEnd(tag);
          }
  
          public int getSpanFlags(Object tag) {
              return mSpanned.getSpanFlags(tag);
          }
  
          public int nextSpanTransition(int start, int end, Class type) {
              return mSpanned.nextSpanTransition(start, end, type);
          }
  
          private Spanned mSpanned;
      }
  }
  