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
|
/* $Id$ */
/*
* This file is part of OpenTTD.
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file alloc_func.hpp Functions related to the allocation of memory */
#ifndef ALLOC_FUNC_HPP
#define ALLOC_FUNC_HPP
/*
* Functions to exit badly with an error message.
* It has to be linked so the error messages are not
* duplicated in each object file making the final
* binary needlessly large.
*/
void NORETURN MallocError(size_t size);
void NORETURN ReallocError(size_t size);
/**
* Checks whether allocating memory would overflow size_t.
*
* @param element_size Size of the structure to allocate.
* @param num_elements Number of elements to allocate.
*/
static inline void CheckAllocationConstraints(size_t element_size, size_t num_elements)
{
if (num_elements > SIZE_MAX / element_size) MallocError(SIZE_MAX);
}
/**
* Checks whether allocating memory would overflow size_t.
*
* @tparam T Structure to allocate.
* @param num_elements Number of elements to allocate.
*/
template <typename T>
static inline void CheckAllocationConstraints(size_t num_elements)
{
CheckAllocationConstraints(sizeof(T), num_elements);
}
/**
* Simplified allocation function that allocates the specified number of
* elements of the given type. It also explicitly casts it to the requested
* type.
* @note throws an error when there is no memory anymore.
* @note the memory contains garbage data (i.e. possibly non-zero values).
* @tparam T the type of the variable(s) to allocation.
* @param num_elements the number of elements to allocate of the given type.
* @return NULL when num_elements == 0, non-NULL otherwise.
*/
template <typename T>
static FORCEINLINE T *MallocT(size_t num_elements)
{
/*
* MorphOS cannot handle 0 elements allocations, or rather that always
* returns NULL. So we do that for *all* allocations, thus causing it
* to behave the same on all OSes.
*/
if (num_elements == 0) return NULL;
/* Ensure the size does not overflow. */
CheckAllocationConstraints<T>(num_elements);
T *t_ptr = (T*)malloc(num_elements * sizeof(T));
if (t_ptr == NULL) MallocError(num_elements * sizeof(T));
return t_ptr;
}
/**
* Simplified allocation function that allocates the specified number of
* elements of the given type. It also explicitly casts it to the requested
* type.
* @note throws an error when there is no memory anymore.
* @note the memory contains all zero values.
* @tparam T the type of the variable(s) to allocation.
* @param num_elements the number of elements to allocate of the given type.
* @return NULL when num_elements == 0, non-NULL otherwise.
*/
template <typename T>
static FORCEINLINE T *CallocT(size_t num_elements)
{
/*
* MorphOS cannot handle 0 elements allocations, or rather that always
* returns NULL. So we do that for *all* allocations, thus causing it
* to behave the same on all OSes.
*/
if (num_elements == 0) return NULL;
T *t_ptr = (T*)calloc(num_elements, sizeof(T));
if (t_ptr == NULL) MallocError(num_elements * sizeof(T));
return t_ptr;
}
/**
* Simplified reallocation function that allocates the specified number of
* elements of the given type. It also explicitly casts it to the requested
* type. It extends/shrinks the memory allocation given in t_ptr.
* @note throws an error when there is no memory anymore.
* @note the pointer to the data may change, but the data will remain valid.
* @tparam T the type of the variable(s) to allocation.
* @param t_ptr the previous allocation to extend/shrink.
* @param num_elements the number of elements to allocate of the given type.
* @return NULL when num_elements == 0, non-NULL otherwise.
*/
template <typename T>
static FORCEINLINE T *ReallocT(T *t_ptr, size_t num_elements)
{
/*
* MorphOS cannot handle 0 elements allocations, or rather that always
* returns NULL. So we do that for *all* allocations, thus causing it
* to behave the same on all OSes.
*/
if (num_elements == 0) {
free(t_ptr);
return NULL;
}
/* Ensure the size does not overflow. */
CheckAllocationConstraints<T>(num_elements);
t_ptr = (T*)realloc(t_ptr, num_elements * sizeof(T));
if (t_ptr == NULL) ReallocError(num_elements * sizeof(T));
return t_ptr;
}
/** alloca() has to be called in the parent function, so define AllocaM() as a macro */
#define AllocaM(T, num_elements) \
(CheckAllocationConstraints<T>(num_elements), \
(T*)alloca((num_elements) * sizeof(T)))
#endif /* ALLOC_FUNC_HPP */
|
