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
|
// Copyright (C) 2011 Milo Yip
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
#ifndef RAPIDJSON_INTERNAL_STACK_H_
#define RAPIDJSON_INTERNAL_STACK_H_
namespace rapidjson {
namespace internal {
///////////////////////////////////////////////////////////////////////////////
// Stack
//! A type-unsafe stack for storing different types of data.
/*! \tparam Allocator Allocator for allocating stack memory.
*/
template <typename Allocator>
class Stack {
public:
// Optimization note: Do not allocate memory for stack_ in constructor.
// Do it lazily when first Push() -> Expand() -> Resize().
Stack(Allocator* allocator, size_t stackCapacity) : allocator_(allocator), ownAllocator(0), stack_(0), stackTop_(0), stackEnd_(0), initialCapacity_(stackCapacity) {
RAPIDJSON_ASSERT(stackCapacity > 0);
if (!allocator_)
ownAllocator = allocator_ = new Allocator();
}
~Stack() {
Allocator::Free(stack_);
delete ownAllocator; // Only delete if it is owned by the stack
}
void Clear() { stackTop_ = stack_; }
void ShrinkToFit() {
if (Empty()) {
// If the stack is empty, completely deallocate the memory.
Allocator::Free(stack_);
stack_ = 0;
stackTop_ = 0;
stackEnd_ = 0;
}
else
Resize(GetSize());
}
// Optimization note: try to minimize the size of this function for force inline.
// Expansion is run very infrequently, so it is moved to another (probably non-inline) function.
template<typename T>
RAPIDJSON_FORCEINLINE T* Push(size_t count = 1) {
// Expand the stack if needed
if (stackTop_ + sizeof(T) * count >= stackEnd_)
Expand<T>(count);
T* ret = reinterpret_cast<T*>(stackTop_);
stackTop_ += sizeof(T) * count;
return ret;
}
template<typename T>
T* Pop(size_t count) {
RAPIDJSON_ASSERT(GetSize() >= count * sizeof(T));
stackTop_ -= count * sizeof(T);
return reinterpret_cast<T*>(stackTop_);
}
template<typename T>
T* Top() {
RAPIDJSON_ASSERT(GetSize() >= sizeof(T));
return reinterpret_cast<T*>(stackTop_ - sizeof(T));
}
template<typename T>
T* Bottom() { return (T*)stack_; }
Allocator& GetAllocator() { return *allocator_; }
bool Empty() const { return stackTop_ == stack_; }
size_t GetSize() const { return static_cast<size_t>(stackTop_ - stack_); }
size_t GetCapacity() const { return static_cast<size_t>(stackEnd_ - stack_); }
private:
template<typename T>
void Expand(size_t count) {
// Only expand the capacity if the current stack exists. Otherwise just create a stack with initial capacity.
size_t newCapacity;
if (stack_ == 0)
newCapacity = initialCapacity_;
else {
newCapacity = GetCapacity();
newCapacity += (newCapacity + 1) / 2;
}
size_t newSize = GetSize() + sizeof(T) * count;
if (newCapacity < newSize)
newCapacity = newSize;
Resize(newCapacity);
}
void Resize(size_t newCapacity) {
const size_t size = GetSize(); // Backup the current size
stack_ = (char*)allocator_->Realloc(stack_, GetCapacity(), newCapacity);
stackTop_ = stack_ + size;
stackEnd_ = stack_ + newCapacity;
}
// Prohibit copy constructor & assignment operator.
Stack(const Stack&);
Stack& operator=(const Stack&);
Allocator* allocator_;
Allocator* ownAllocator;
char *stack_;
char *stackTop_;
char *stackEnd_;
size_t initialCapacity_;
};
} // namespace internal
} // namespace rapidjson
#endif // RAPIDJSON_STACK_H_
|
