1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
/*
* Copyright (C) 2006, 2009 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_GLYPH_METRICS_MAP_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_GLYPH_METRICS_MAP_H_
#include <memory>
#include <optional>
#include "base/compiler_specific.h"
#include "base/memory/ptr_util.h"
#include "third_party/blink/renderer/platform/fonts/glyph.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/assertions.h"
#include "ui/gfx/geometry/rect_f.h"
namespace blink {
template <class T>
class GlyphMetricsMap {
USING_FAST_MALLOC(GlyphMetricsMap);
public:
GlyphMetricsMap() : filled_primary_page_(false) {}
GlyphMetricsMap(const GlyphMetricsMap&) = delete;
GlyphMetricsMap& operator=(const GlyphMetricsMap&) = delete;
std::optional<T> MetricsForGlyph(Glyph glyph) {
return LocatePage(glyph / GlyphMetricsPage::kSize)->MetricsForGlyph(glyph);
}
void SetMetricsForGlyph(Glyph glyph, const T& metrics) {
LocatePage(glyph / GlyphMetricsPage::kSize)
->SetMetricsForGlyph(glyph, metrics);
}
private:
class GlyphMetricsPage {
USING_FAST_MALLOC(GlyphMetricsPage);
public:
GlyphMetricsPage(const GlyphMetricsPage&) = delete;
GlyphMetricsPage& operator=(const GlyphMetricsPage&) = delete;
static const size_t kSize =
256; // Usually covers Latin-1 in a single page.
GlyphMetricsPage() {}
std::optional<T> MetricsForGlyph(Glyph glyph) const {
// SAFETY: `glyph` is unsigned, `kSize` is the size of the
// `metrics_` array, so `glyph % kSize` is in-bounds.
T value = UNSAFE_BUFFERS(metrics_[glyph % kSize]);
if (value == UnknownMetrics())
return std::nullopt;
return value;
}
void SetMetricsForGlyph(Glyph glyph, const T& metrics) {
// SAFETY: `glyph` is unsigned, `kSize` is the size of the
// `metrics_` array, so `glyph % kSize` is in-bounds.
UNSAFE_BUFFERS(SetMetricsForIndex(glyph % kSize, metrics));
}
UNSAFE_BUFFER_USAGE void SetMetricsForIndex(unsigned index,
const T& metrics) {
// SAFETY: required from caller, enforced by UNSAFE_BUFFER_USAGE.
SECURITY_DCHECK(index < kSize);
UNSAFE_BUFFERS(metrics_[index] = metrics);
}
private:
T metrics_[kSize];
};
GlyphMetricsPage* LocatePage(unsigned page_number) {
if (!page_number && filled_primary_page_)
return &primary_page_;
return LocatePageSlowCase(page_number);
}
GlyphMetricsPage* LocatePageSlowCase(unsigned page_number);
static constexpr T UnknownMetrics();
bool filled_primary_page_;
// We optimize for the page that contains glyph indices 0-255.
GlyphMetricsPage primary_page_;
std::unique_ptr<HashMap<int, std::unique_ptr<GlyphMetricsPage>>> pages_;
};
template <>
inline constexpr float GlyphMetricsMap<float>::UnknownMetrics() {
return -1;
}
template <>
inline constexpr gfx::RectF GlyphMetricsMap<gfx::RectF>::UnknownMetrics() {
return gfx::RectF(std::numeric_limits<float>::min(), 0, 0, 0);
}
template <class T>
typename GlyphMetricsMap<T>::GlyphMetricsPage*
GlyphMetricsMap<T>::LocatePageSlowCase(unsigned page_number) {
GlyphMetricsPage* page;
if (!page_number) {
DCHECK(!filled_primary_page_);
page = &primary_page_;
filled_primary_page_ = true;
} else {
if (pages_) {
auto it = pages_->find(page_number);
if (it != pages_->end())
return it->value.get();
} else {
pages_ =
std::make_unique<HashMap<int, std::unique_ptr<GlyphMetricsPage>>>();
}
page = new GlyphMetricsPage;
pages_->Set(page_number, base::WrapUnique(page));
}
// Fill in the whole page with the unknown glyph information.
for (unsigned i = 0; i < GlyphMetricsPage::kSize; i++) {
// SAFETY: `kSize` is the size of the metrics array to be indexed.
UNSAFE_BUFFERS(page->SetMetricsForIndex(i, UnknownMetrics()));
}
return page;
}
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_GLYPH_METRICS_MAP_H_
|
