content: /*
   * Copyright (C) 2012 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;
  
  import android.annotation.UnsupportedAppUsage;
  import java.lang.reflect.Array;
  import java.util.Arrays;
  
  /**
   * A cached set of spans. Caches the result of {@link Spanned#getSpans(int, int, Class)} and then
   * provides faster access to {@link Spanned#nextSpanTransition(int, int, Class)}.
   *
   * Fields are left public for a convenient direct access.
   *
   * Note that empty spans are ignored by this class.
   * @hide
   */
  public class SpanSet<E> {
      private final Class<? extends E> classType;
  
      int numberOfSpans;
      @UnsupportedAppUsage
      E[] spans;
      int[] spanStarts;
      int[] spanEnds;
      int[] spanFlags;
  
      SpanSet(Class<? extends E> type) {
          classType = type;
          numberOfSpans = 0;
      }
  
      @SuppressWarnings("unchecked")
      public void init(Spanned spanned, int start, int limit) {
          final E[] allSpans = spanned.getSpans(start, limit, classType);
          final int length = allSpans.length;
  
          if (length > 0 && (spans == null || spans.length < length)) {
              // These arrays may end up being too large because of the discarded empty spans
              spans = (E[]) Array.newInstance(classType, length);
              spanStarts = new int[length];
              spanEnds = new int[length];
              spanFlags = new int[length];
          }
  
          int prevNumberOfSpans = numberOfSpans;
          numberOfSpans = 0;
          for (int i = 0; i < length; i++) {
              final E span = allSpans[i];
  
              final int spanStart = spanned.getSpanStart(span);
              final int spanEnd = spanned.getSpanEnd(span);
              if (spanStart == spanEnd) continue;
  
              final int spanFlag = spanned.getSpanFlags(span);
  
              spans[numberOfSpans] = span;
              spanStarts[numberOfSpans] = spanStart;
              spanEnds[numberOfSpans] = spanEnd;
              spanFlags[numberOfSpans] = spanFlag;
  
              numberOfSpans++;
          }
  
          // cleanup extra spans left over from previous init() call
          if (numberOfSpans < prevNumberOfSpans) {
              // prevNumberofSpans was > 0, therefore spans != null
              Arrays.fill(spans, numberOfSpans, prevNumberOfSpans, null);
          }
      }
  
      /**
       * Returns true if there are spans intersecting the given interval.
       * @param end must be strictly greater than start
       */
      public boolean hasSpansIntersecting(int start, int end) {
          for (int i = 0; i < numberOfSpans; i++) {
              // equal test is valid since both intervals are not empty by construction
              if (spanStarts[i] >= end || spanEnds[i] <= start) continue;
              return true;
          }
          return false;
      }
  
      /**
       * Similar to {@link Spanned#nextSpanTransition(int, int, Class)}
       */
      int getNextTransition(int start, int limit) {
          for (int i = 0; i < numberOfSpans; i++) {
              final int spanStart = spanStarts[i];
              final int spanEnd = spanEnds[i];
              if (spanStart > start && spanStart < limit) limit = spanStart;
              if (spanEnd > start && spanEnd < limit) limit = spanEnd;
          }
          return limit;
      }
  
      /**
       * Removes all internal references to the spans to avoid memory leaks.
       */
      public void recycle() {
          if (spans != null) {
              Arrays.fill(spans, 0, numberOfSpans, null);
          }
      }
  }
  