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 import java.util.Arrays; 21 22 /** 23 * A cached set of spans. Caches the result of {@link Spanned#getSpans(int, int, Class)} and then 24 * provides faster access to {@link Spanned#nextSpanTransition(int, int, Class)}. 25 * 26 * Fields are left public for a convenient direct access. 27 * 28 * Note that empty spans are ignored by this class. 29 * @hide 30 */ 31 public class SpanSet<E> { 32 private final Class<? extends E> classType; 33 34 int numberOfSpans; 35 E[] spans; 36 int[] spanStarts; 37 int[] spanEnds; 38 int[] spanFlags; 39 SpanSet(Class<? extends E> type)40 SpanSet(Class<? extends E> type) { 41 classType = type; 42 numberOfSpans = 0; 43 } 44 45 @SuppressWarnings("unchecked") init(Spanned spanned, int start, int limit)46 public void init(Spanned spanned, int start, int limit) { 47 final E[] allSpans = spanned.getSpans(start, limit, classType); 48 final int length = allSpans.length; 49 50 if (length > 0 && (spans == null || spans.length < length)) { 51 // These arrays may end up being too large because of the discarded empty spans 52 spans = (E[]) Array.newInstance(classType, length); 53 spanStarts = new int[length]; 54 spanEnds = new int[length]; 55 spanFlags = new int[length]; 56 } 57 58 int prevNumberOfSpans = numberOfSpans; 59 numberOfSpans = 0; 60 for (int i = 0; i < length; i++) { 61 final E span = allSpans[i]; 62 63 final int spanStart = spanned.getSpanStart(span); 64 final int spanEnd = spanned.getSpanEnd(span); 65 if (spanStart == spanEnd) continue; 66 67 final int spanFlag = spanned.getSpanFlags(span); 68 69 spans[numberOfSpans] = span; 70 spanStarts[numberOfSpans] = spanStart; 71 spanEnds[numberOfSpans] = spanEnd; 72 spanFlags[numberOfSpans] = spanFlag; 73 74 numberOfSpans++; 75 } 76 77 // cleanup extra spans left over from previous init() call 78 if (numberOfSpans < prevNumberOfSpans) { 79 // prevNumberofSpans was > 0, therefore spans != null 80 Arrays.fill(spans, numberOfSpans, prevNumberOfSpans, null); 81 } 82 } 83 84 /** 85 * Returns true if there are spans intersecting the given interval. 86 * @param end must be strictly greater than start 87 */ hasSpansIntersecting(int start, int end)88 public boolean hasSpansIntersecting(int start, int end) { 89 for (int i = 0; i < numberOfSpans; i++) { 90 // equal test is valid since both intervals are not empty by construction 91 if (spanStarts[i] >= end || spanEnds[i] <= start) continue; 92 return true; 93 } 94 return false; 95 } 96 97 /** 98 * Similar to {@link Spanned#nextSpanTransition(int, int, Class)} 99 */ getNextTransition(int start, int limit)100 int getNextTransition(int start, int limit) { 101 for (int i = 0; i < numberOfSpans; i++) { 102 final int spanStart = spanStarts[i]; 103 final int spanEnd = spanEnds[i]; 104 if (spanStart > start && spanStart < limit) limit = spanStart; 105 if (spanEnd > start && spanEnd < limit) limit = spanEnd; 106 } 107 return limit; 108 } 109 110 /** 111 * Removes all internal references to the spans to avoid memory leaks. 112 */ recycle()113 public void recycle() { 114 if (spans != null) { 115 Arrays.fill(spans, 0, numberOfSpans, null); 116 } 117 } 118 } 119