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