1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.text; 18 19 import java.lang.reflect.Array; 20 21 /** 22 * A cached set of spans. Caches the result of {@link Spanned#getSpans(int, int, Class)} and then 23 * provides faster access to {@link Spanned#nextSpanTransition(int, int, Class)}. 24 * 25 * Fields are left public for a convenient direct access. 26 * 27 * Note that empty spans are ignored by this class. 28 * @hide 29 */ 30 public class SpanSet<E> { 31 private final Class<? extends E> classType; 32 33 int numberOfSpans; 34 E[] spans; 35 int[] spanStarts; 36 int[] spanEnds; 37 int[] spanFlags; 38 SpanSet(Class<? extends E> type)39 SpanSet(Class<? extends E> type) { 40 classType = type; 41 numberOfSpans = 0; 42 } 43 44 @SuppressWarnings("unchecked") init(Spanned spanned, int start, int limit)45 public void init(Spanned spanned, int start, int limit) { 46 final E[] allSpans = spanned.getSpans(start, limit, classType); 47 final int length = allSpans.length; 48 49 if (length > 0 && (spans == null || spans.length < length)) { 50 // These arrays may end up being too large because of the discarded empty spans 51 spans = (E[]) Array.newInstance(classType, length); 52 spanStarts = new int[length]; 53 spanEnds = new int[length]; 54 spanFlags = new int[length]; 55 } 56 57 numberOfSpans = 0; 58 for (int i = 0; i < length; i++) { 59 final E span = allSpans[i]; 60 61 final int spanStart = spanned.getSpanStart(span); 62 final int spanEnd = spanned.getSpanEnd(span); 63 if (spanStart == spanEnd) continue; 64 65 final int spanFlag = spanned.getSpanFlags(span); 66 67 spans[numberOfSpans] = span; 68 spanStarts[numberOfSpans] = spanStart; 69 spanEnds[numberOfSpans] = spanEnd; 70 spanFlags[numberOfSpans] = spanFlag; 71 72 numberOfSpans++; 73 } 74 } 75 76 /** 77 * Returns true if there are spans intersecting the given interval. 78 * @param end must be strictly greater than start 79 */ hasSpansIntersecting(int start, int end)80 public boolean hasSpansIntersecting(int start, int end) { 81 for (int i = 0; i < numberOfSpans; i++) { 82 // equal test is valid since both intervals are not empty by construction 83 if (spanStarts[i] >= end || spanEnds[i] <= start) continue; 84 return true; 85 } 86 return false; 87 } 88 89 /** 90 * Similar to {@link Spanned#nextSpanTransition(int, int, Class)} 91 */ getNextTransition(int start, int limit)92 int getNextTransition(int start, int limit) { 93 for (int i = 0; i < numberOfSpans; i++) { 94 final int spanStart = spanStarts[i]; 95 final int spanEnd = spanEnds[i]; 96 if (spanStart > start && spanStart < limit) limit = spanStart; 97 if (spanEnd > start && spanEnd < limit) limit = spanEnd; 98 } 99 return limit; 100 } 101 102 /** 103 * Removes all internal references to the spans to avoid memory leaks. 104 */ recycle()105 public void recycle() { 106 // The spans array is guaranteed to be not null when numberOfSpans is > 0 107 for (int i = 0; i < numberOfSpans; i++) { 108 spans[i] = null; // prevent a leak: no reference kept when TextLine is recycled 109 } 110 } 111 } 112