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 android.compat.annotation.UnsupportedAppUsage; 20 import android.os.Build; 21 22 import java.lang.reflect.Array; 23 import java.util.Arrays; 24 25 /** 26 * A cached set of spans. Caches the result of {@link Spanned#getSpans(int, int, Class)} and then 27 * provides faster access to {@link Spanned#nextSpanTransition(int, int, Class)}. 28 * 29 * Fields are left public for a convenient direct access. 30 * 31 * Note that empty spans are ignored by this class. 32 * @hide 33 */ 34 @android.ravenwood.annotation.RavenwoodKeepWholeClass 35 public class SpanSet<E> { 36 private final Class<? extends E> classType; 37 38 int numberOfSpans; 39 @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553) 40 E[] spans; 41 int[] spanStarts; 42 int[] spanEnds; 43 int[] spanFlags; 44 SpanSet(Class<? extends E> type)45 SpanSet(Class<? extends E> type) { 46 classType = type; 47 numberOfSpans = 0; 48 } 49 50 @SuppressWarnings("unchecked") init(Spanned spanned, int start, int limit)51 public void init(Spanned spanned, int start, int limit) { 52 final E[] allSpans = spanned.getSpans(start, limit, classType); 53 final int length = allSpans.length; 54 55 if (length > 0 && (spans == null || spans.length < length)) { 56 // These arrays may end up being too large because of the discarded empty spans 57 spans = (E[]) Array.newInstance(classType, length); 58 spanStarts = new int[length]; 59 spanEnds = new int[length]; 60 spanFlags = new int[length]; 61 } 62 63 int prevNumberOfSpans = numberOfSpans; 64 numberOfSpans = 0; 65 for (int i = 0; i < length; i++) { 66 final E span = allSpans[i]; 67 68 final int spanStart = spanned.getSpanStart(span); 69 final int spanEnd = spanned.getSpanEnd(span); 70 if (spanStart == spanEnd) continue; 71 72 final int spanFlag = spanned.getSpanFlags(span); 73 74 spans[numberOfSpans] = span; 75 spanStarts[numberOfSpans] = spanStart; 76 spanEnds[numberOfSpans] = spanEnd; 77 spanFlags[numberOfSpans] = spanFlag; 78 79 numberOfSpans++; 80 } 81 82 // cleanup extra spans left over from previous init() call 83 if (numberOfSpans < prevNumberOfSpans) { 84 // prevNumberofSpans was > 0, therefore spans != null 85 Arrays.fill(spans, numberOfSpans, prevNumberOfSpans, null); 86 } 87 } 88 89 /** 90 * Returns true if there are spans intersecting the given interval. 91 * @param end must be strictly greater than start 92 */ hasSpansIntersecting(int start, int end)93 public boolean hasSpansIntersecting(int start, int end) { 94 for (int i = 0; i < numberOfSpans; i++) { 95 // equal test is valid since both intervals are not empty by construction 96 if (spanStarts[i] >= end || spanEnds[i] <= start) continue; 97 return true; 98 } 99 return false; 100 } 101 102 /** 103 * Similar to {@link Spanned#nextSpanTransition(int, int, Class)} 104 */ getNextTransition(int start, int limit)105 int getNextTransition(int start, int limit) { 106 for (int i = 0; i < numberOfSpans; i++) { 107 final int spanStart = spanStarts[i]; 108 final int spanEnd = spanEnds[i]; 109 if (spanStart > start && spanStart < limit) limit = spanStart; 110 if (spanEnd > start && spanEnd < limit) limit = spanEnd; 111 } 112 return limit; 113 } 114 115 /** 116 * Removes all internal references to the spans to avoid memory leaks. 117 */ recycle()118 public void recycle() { 119 if (spans != null) { 120 Arrays.fill(spans, 0, numberOfSpans, null); 121 } 122 } 123 } 124