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
|
/****************************************************************************
**
** Copyright (C) 2021 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:COMM$
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** $QT_END_LICENSE$
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
****************************************************************************/
#include "qplatformdefs.h"
#include <stdlib.h>
#include <string.h>
/*
Define the container allocation functions in a separate file, so that our
users can easily override them.
*/
QT_BEGIN_NAMESPACE
#if !QT_DEPRECATED_SINCE(5, 0)
// Make sure they're defined to be exported
Q_CORE_EXPORT void *qMalloc(size_t size) Q_ALLOC_SIZE(1);
Q_CORE_EXPORT void qFree(void *ptr);
Q_CORE_EXPORT void *qRealloc(void *ptr, size_t size) Q_ALLOC_SIZE(2);
#endif
void *qMalloc(size_t size)
{
return ::malloc(size);
}
void qFree(void *ptr)
{
::free(ptr);
}
void *qRealloc(void *ptr, size_t size)
{
return ::realloc(ptr, size);
}
void *qMallocAligned(size_t size, size_t alignment)
{
return qReallocAligned(nullptr, size, 0, alignment);
}
void *qReallocAligned(void *oldptr, size_t newsize, size_t oldsize, size_t alignment)
{
// fake an aligned allocation
void *actualptr = oldptr ? static_cast<void **>(oldptr)[-1] : nullptr;
if (alignment <= sizeof(void*)) {
// special, fast case
void **newptr = static_cast<void **>(realloc(actualptr, newsize + sizeof(void*)));
if (!newptr)
return nullptr;
if (newptr == actualptr) {
// realloc succeeded without reallocating
return oldptr;
}
*newptr = newptr;
return newptr + 1;
}
// malloc returns pointers aligned at least at sizeof(size_t) boundaries
// but usually more (8- or 16-byte boundaries).
// So we overallocate by alignment-sizeof(size_t) bytes, so we're guaranteed to find a
// somewhere within the first alignment-sizeof(size_t) that is properly aligned.
// However, we need to store the actual pointer, so we need to allocate actually size +
// alignment anyway.
void *real = realloc(actualptr, newsize + alignment);
if (!real)
return nullptr;
quintptr faked = reinterpret_cast<quintptr>(real) + alignment;
faked &= ~(alignment - 1);
void **faked_ptr = reinterpret_cast<void **>(faked);
if (oldptr) {
qptrdiff oldoffset = static_cast<char *>(oldptr) - static_cast<char *>(actualptr);
qptrdiff newoffset = reinterpret_cast<char *>(faked_ptr) - static_cast<char *>(real);
if (oldoffset != newoffset)
memmove(faked_ptr, static_cast<char *>(real) + oldoffset, qMin(oldsize, newsize));
}
// now save the value of the real pointer at faked-sizeof(void*)
// by construction, alignment > sizeof(void*) and is a power of 2, so
// faked-sizeof(void*) is properly aligned for a pointer
faked_ptr[-1] = real;
return faked_ptr;
}
void qFreeAligned(void *ptr)
{
if (!ptr)
return;
void **ptr2 = static_cast<void **>(ptr);
free(ptr2[-1]);
}
QT_END_NAMESPACE
|
