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
|
/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: itkTimeStamp.cxx
Language: C++
Date: $Date$
Version: $Revision$
Copyright (c) Insight Software Consortium. All rights reserved.
See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
Portions of this code are covered under the VTK copyright.
See VTKCopyright.txt or http://www.kitware.com/VTKCopyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
#include "itkTimeStamp.h"
#include "itkFastMutexLock.h"
#if defined(_WIN32)
#include "itkWindows.h"
#elif defined(__APPLE__)
// OSAtomic.h optimizations only used in 10.5 and later
#include <AvailabilityMacros.h>
#if MAC_OS_X_VERSION_MAX_ALLOWED >= 1050
#include <libkern/OSAtomic.h>
#endif
#elif defined(__GLIBCPP__) || defined(__GLIBCXX__)
#if (__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 2))
# include <ext/atomicity.h>
#else
# include <bits/atomicity.h>
#endif
#endif
namespace itk
{
#if defined(__GLIBCXX__) // g++ 3.4+
using __gnu_cxx::__exchange_and_add;
#endif
/**
* Instance creation.
*/
TimeStamp*
TimeStamp
::New()
{
return new Self;
}
/**
* Make sure the new time stamp is greater than all others so far.
*/
void
TimeStamp
::Modified()
{
// Windows optimization
#if defined(WIN32) || defined(_WIN32)
static LONG itkTimeStampTime = 0;
m_ModifiedTime = (unsigned long)InterlockedIncrement(&itkTimeStampTime);
// Mac optimization
#elif defined(__APPLE__) && (MAC_OS_X_VERSION_MIN_REQUIRED >= 1050)
#if __LP64__
// "m_ModifiedTime" is "unsigned long", a type that changess sizes
// depending on architecture. The atomic increment is safe, since it
// operates on a variable of the exact type needed. The cast does not
// change the size, but does change signedness, which is not ideal.
static volatile int64_t itkTimeStampTime = 0;
m_ModifiedTime = (unsigned long)OSAtomicIncrement64Barrier(&itkTimeStampTime);
#else
static volatile int32_t itkTimeStampTime = 0;
m_ModifiedTime = (unsigned long)OSAtomicIncrement32Barrier(&itkTimeStampTime);
#endif
// gcc optimization
#elif defined(__GLIBCPP__) || defined(__GLIBCXX__)
// We start from 1 since __exchange_and_add returns the old (non-incremented)
// value. This is not really necessary but will make the absolute value of the
// timestamp more consistent across platforms.
static volatile _Atomic_word itkTimeStampTime = 1;
m_ModifiedTime = (unsigned long)__exchange_and_add(&itkTimeStampTime, 1);
// General case
#else
/**
* Initialize static member
*/
static unsigned long itkTimeStampTime = 0;
/** Used for mutex locking */
static SimpleFastMutexLock TimeStampMutex;
TimeStampMutex.Lock();
m_ModifiedTime = ++itkTimeStampTime;
TimeStampMutex.Unlock();
#endif
}
} // end namespace itk
|
