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
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "platform/graphics/ContiguousContainer.h"
#include "wtf/Allocator.h"
#include "wtf/ContainerAnnotations.h"
#include "wtf/PtrUtil.h"
#include "wtf/allocator/Partitions.h"
#include <algorithm>
#include <memory>
namespace blink {
// Default number of max-sized elements to allocate space for, if there is no
// initial buffer.
static const unsigned kDefaultInitialBufferSize = 32;
class ContiguousContainerBase::Buffer {
WTF_MAKE_NONCOPYABLE(Buffer);
USING_FAST_MALLOC(Buffer);
public:
Buffer(size_t bufferSize, const char* typeName) {
m_capacity = WTF::Partitions::bufferActualSize(bufferSize);
m_begin = m_end =
static_cast<char*>(WTF::Partitions::bufferMalloc(m_capacity, typeName));
ANNOTATE_NEW_BUFFER(m_begin, m_capacity, 0);
}
~Buffer() {
ANNOTATE_DELETE_BUFFER(m_begin, m_capacity, usedCapacity());
WTF::Partitions::bufferFree(m_begin);
}
size_t capacity() const { return m_capacity; }
size_t usedCapacity() const { return m_end - m_begin; }
size_t unusedCapacity() const { return capacity() - usedCapacity(); }
bool isEmpty() const { return usedCapacity() == 0; }
void* allocate(size_t objectSize) {
ASSERT(unusedCapacity() >= objectSize);
ANNOTATE_CHANGE_SIZE(m_begin, m_capacity, usedCapacity(),
usedCapacity() + objectSize);
void* result = m_end;
m_end += objectSize;
return result;
}
void deallocateLastObject(void* object) {
RELEASE_ASSERT(m_begin <= object && object < m_end);
ANNOTATE_CHANGE_SIZE(m_begin, m_capacity, usedCapacity(),
static_cast<char*>(object) - m_begin);
m_end = static_cast<char*>(object);
}
private:
// m_begin <= m_end <= m_begin + m_capacity
char* m_begin;
char* m_end;
size_t m_capacity;
};
ContiguousContainerBase::ContiguousContainerBase(size_t maxObjectSize)
: m_endIndex(0), m_maxObjectSize(maxObjectSize) {}
ContiguousContainerBase::ContiguousContainerBase(
ContiguousContainerBase&& source)
: ContiguousContainerBase(source.m_maxObjectSize) {
swap(source);
}
ContiguousContainerBase::~ContiguousContainerBase() {}
ContiguousContainerBase& ContiguousContainerBase::operator=(
ContiguousContainerBase&& source) {
swap(source);
return *this;
}
size_t ContiguousContainerBase::capacityInBytes() const {
size_t capacity = 0;
for (const auto& buffer : m_buffers)
capacity += buffer->capacity();
return capacity;
}
size_t ContiguousContainerBase::usedCapacityInBytes() const {
size_t usedCapacity = 0;
for (const auto& buffer : m_buffers)
usedCapacity += buffer->usedCapacity();
return usedCapacity;
}
size_t ContiguousContainerBase::memoryUsageInBytes() const {
return sizeof(*this) + capacityInBytes() +
m_elements.capacity() * sizeof(m_elements[0]);
}
void ContiguousContainerBase::reserveInitialCapacity(size_t bufferSize,
const char* typeName) {
allocateNewBufferForNextAllocation(bufferSize, typeName);
}
void* ContiguousContainerBase::allocate(size_t objectSize,
const char* typeName) {
ASSERT(objectSize <= m_maxObjectSize);
Buffer* bufferForAlloc = nullptr;
if (!m_buffers.isEmpty()) {
Buffer* endBuffer = m_buffers[m_endIndex].get();
if (endBuffer->unusedCapacity() >= objectSize)
bufferForAlloc = endBuffer;
else if (m_endIndex + 1 < m_buffers.size())
bufferForAlloc = m_buffers[++m_endIndex].get();
}
if (!bufferForAlloc) {
size_t newBufferSize = m_buffers.isEmpty()
? kDefaultInitialBufferSize * m_maxObjectSize
: 2 * m_buffers.back()->capacity();
bufferForAlloc =
allocateNewBufferForNextAllocation(newBufferSize, typeName);
}
void* element = bufferForAlloc->allocate(objectSize);
m_elements.push_back(element);
return element;
}
void ContiguousContainerBase::removeLast() {
void* object = m_elements.back();
m_elements.pop_back();
Buffer* endBuffer = m_buffers[m_endIndex].get();
endBuffer->deallocateLastObject(object);
if (endBuffer->isEmpty()) {
if (m_endIndex > 0)
m_endIndex--;
if (m_endIndex + 2 < m_buffers.size())
m_buffers.pop_back();
}
}
void ContiguousContainerBase::clear() {
m_elements.clear();
m_buffers.clear();
m_endIndex = 0;
}
void ContiguousContainerBase::swap(ContiguousContainerBase& other) {
m_elements.swap(other.m_elements);
m_buffers.swap(other.m_buffers);
std::swap(m_endIndex, other.m_endIndex);
std::swap(m_maxObjectSize, other.m_maxObjectSize);
}
void ContiguousContainerBase::shrinkToFit() {
while (m_endIndex < m_buffers.size() - 1) {
DCHECK(m_buffers.back()->isEmpty());
m_buffers.pop_back();
}
}
ContiguousContainerBase::Buffer*
ContiguousContainerBase::allocateNewBufferForNextAllocation(
size_t bufferSize,
const char* typeName) {
ASSERT(m_buffers.isEmpty() || m_endIndex == m_buffers.size() - 1);
std::unique_ptr<Buffer> newBuffer =
WTF::makeUnique<Buffer>(bufferSize, typeName);
Buffer* bufferToReturn = newBuffer.get();
m_buffers.push_back(std::move(newBuffer));
m_endIndex = m_buffers.size() - 1;
return bufferToReturn;
}
} // namespace blink
|
