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
|
// This code contains NVIDIA Confidential Information and is disclosed to you
// under a form of NVIDIA software license agreement provided separately to you.
//
// Notice
// NVIDIA Corporation and its licensors retain all intellectual property and
// proprietary rights in and to this software and related documentation and
// any modifications thereto. Any use, reproduction, disclosure, or
// distribution of this software and related documentation without an express
// license agreement from NVIDIA Corporation is strictly prohibited.
//
// ALL NVIDIA DESIGN SPECIFICATIONS, CODE ARE PROVIDED "AS IS.". NVIDIA MAKES
// NO WARRANTIES, EXPRESSED, IMPLIED, STATUTORY, OR OTHERWISE WITH RESPECT TO
// THE MATERIALS, AND EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES OF NONINFRINGEMENT,
// MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE.
//
// Information and code furnished is believed to be accurate and reliable.
// However, NVIDIA Corporation assumes no responsibility for the consequences of use of such
// information or for any infringement of patents or other rights of third parties that may
// result from its use. No license is granted by implication or otherwise under any patent
// or patent rights of NVIDIA Corporation. Details are subject to change without notice.
// This code supersedes and replaces all information previously supplied.
// NVIDIA Corporation products are not authorized for use as critical
// components in life support devices or systems without express written approval of
// NVIDIA Corporation.
//
// Copyright (c) 2008-2020 NVIDIA Corporation. All rights reserved.
// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
#pragma once
#include "NvCloth/Callbacks.h"
#if NV_LINUX_FAMILY
#include <stdint.h> // intptr_t
#endif
namespace nv
{
namespace cloth
{
template <size_t align>
class StackAllocator
{
typedef unsigned char byte;
// todo: switch to offsets so size is consistent on x64
// mSize is just for book keeping so could be 4 bytes
struct Header
{
Header* mPrev;
size_t mSize : 31;
size_t mFree : 1;
};
StackAllocator(const StackAllocator&);
StackAllocator& operator = (const StackAllocator&);
public:
StackAllocator(void* buffer, size_t bufferSize)
: mBuffer(reinterpret_cast<byte*>(buffer)), mBufferSize(bufferSize), mFreeStart(mBuffer), mTop(0)
{
}
~StackAllocator()
{
NV_CLOTH_ASSERT(userBytes() == 0);
}
void* allocate(size_t numBytes)
{
// this is non-standard
if (!numBytes)
return 0;
uintptr_t unalignedStart = uintptr_t(mFreeStart) + sizeof(Header);
byte* allocStart = reinterpret_cast<byte*>((unalignedStart + (align - 1)) & ~(align - 1));
byte* allocEnd = allocStart + numBytes;
// ensure there is space for the alloc
NV_CLOTH_ASSERT(allocEnd <= mBuffer + mBufferSize);
Header* h = getHeader(allocStart);
h->mPrev = mTop;
h->mSize = numBytes;
h->mFree = false;
mTop = h;
mFreeStart = allocEnd;
return allocStart;
}
void deallocate(void* p)
{
if (!p)
return;
Header* h = getHeader(p);
h->mFree = true;
// unwind the stack to the next live alloc
while (mTop && mTop->mFree)
{
mFreeStart = reinterpret_cast<byte*>(mTop);
mTop = mTop->mPrev;
}
}
private:
// return the header for an allocation
inline Header* getHeader(void* p) const
{
NV_CLOTH_ASSERT((reinterpret_cast<uintptr_t>(p) & (align - 1)) == 0);
NV_CLOTH_ASSERT(reinterpret_cast<byte*>(p) >= mBuffer + sizeof(Header));
NV_CLOTH_ASSERT(reinterpret_cast<byte*>(p) < mBuffer + mBufferSize);
return reinterpret_cast<Header*>(p) - 1;
}
public:
// total user-allocated bytes not including any overhead
size_t userBytes() const
{
size_t total = 0;
Header* iter = mTop;
while (iter)
{
total += iter->mSize;
iter = iter->mPrev;
}
return total;
}
// total user-allocated bytes + overhead
size_t totalUsedBytes() const
{
return mFreeStart - mBuffer;
}
size_t remainingBytes() const
{
return mBufferSize - totalUsedBytes();
}
size_t wastedBytes() const
{
return totalUsedBytes() - userBytes();
}
private:
byte* const mBuffer;
const size_t mBufferSize;
byte* mFreeStart; // start of free space
Header* mTop; // top allocation header
};
} // namespace cloth
} // namespace nv
|