1/*
2 * Copyright (C) 2017 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "MarkedText.h"
28
29#include <algorithm>
30#include <wtf/HashSet.h>
31
32namespace WebCore {
33
34Vector<MarkedText> subdivide(const Vector<MarkedText>& markedTexts, OverlapStrategy overlapStrategy)
35{
36 if (markedTexts.isEmpty())
37 return { };
38
39 struct Offset {
40 enum Kind { Begin, End };
41 Kind kind;
42 unsigned value; // Copy of markedText.startOffset/endOffset to avoid the need to branch based on kind.
43 const MarkedText* markedText;
44 };
45
46 // 1. Build table of all offsets.
47 Vector<Offset> offsets;
48 ASSERT(markedTexts.size() < std::numeric_limits<unsigned>::max() / 2);
49 unsigned numberOfMarkedTexts = markedTexts.size();
50 unsigned numberOfOffsets = 2 * numberOfMarkedTexts;
51 offsets.reserveInitialCapacity(numberOfOffsets);
52 for (auto& markedText : markedTexts) {
53 offsets.uncheckedAppend({ Offset::Begin, markedText.startOffset, &markedText });
54 offsets.uncheckedAppend({ Offset::End, markedText.endOffset, &markedText });
55 }
56
57 // 2. Sort offsets such that begin offsets are in paint order and end offsets are in reverse paint order.
58 std::sort(offsets.begin(), offsets.end(), [] (const Offset& a, const Offset& b) {
59 return a.value < b.value || (a.value == b.value && a.kind == b.kind && a.kind == Offset::Begin && a.markedText->type < b.markedText->type)
60 || (a.value == b.value && a.kind == b.kind && a.kind == Offset::End && a.markedText->type > b.markedText->type);
61 });
62
63 // 3. Compute intersection.
64 Vector<MarkedText> result;
65 result.reserveInitialCapacity(numberOfMarkedTexts);
66 HashSet<const MarkedText*> processedMarkedTexts;
67 unsigned offsetSoFar = offsets[0].value;
68 for (unsigned i = 1; i < numberOfOffsets; ++i) {
69 if (offsets[i].value > offsets[i - 1].value) {
70 if (overlapStrategy == OverlapStrategy::Frontmost) {
71 Optional<unsigned> frontmost;
72 for (unsigned j = 0; j < i; ++j) {
73 if (!processedMarkedTexts.contains(offsets[j].markedText) && (!frontmost || offsets[j].markedText->type > offsets[*frontmost].markedText->type))
74 frontmost = j;
75 }
76 if (frontmost)
77 result.append({ offsetSoFar, offsets[i].value, offsets[*frontmost].markedText->type, offsets[*frontmost].markedText->marker });
78 } else {
79 // The appended marked texts may not be in paint order. We will fix this up at the end of this function.
80 for (unsigned j = 0; j < i; ++j) {
81 if (!processedMarkedTexts.contains(offsets[j].markedText))
82 result.append({ offsetSoFar, offsets[i].value, offsets[j].markedText->type, offsets[j].markedText->marker });
83 }
84 }
85 offsetSoFar = offsets[i].value;
86 }
87 if (offsets[i].kind == Offset::End)
88 processedMarkedTexts.add(offsets[i].markedText);
89 }
90 // Fix up; sort the marked texts so that they are in paint order.
91 if (overlapStrategy == OverlapStrategy::None)
92 std::sort(result.begin(), result.end(), [] (const MarkedText& a, const MarkedText& b) { return a.startOffset < b.startOffset || (a.startOffset == b.startOffset && a.type < b.type); });
93 return result;
94}
95
96}
97
98
99