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Location: cpp/openttd-patchpack/source/src/core/alloc_func.hpp
r24263:09a2277924d6
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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 | /*
* 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 nullptr when num_elements == 0, non-nullptr otherwise.
*/
template <typename T>
static inline T *MallocT(size_t num_elements)
{
/*
* MorphOS cannot handle 0 elements allocations, or rather that always
* returns nullptr. So we do that for *all* allocations, thus causing it
* to behave the same on all OSes.
*/
if (num_elements == 0) return nullptr;
/* Ensure the size does not overflow. */
CheckAllocationConstraints<T>(num_elements);
T *t_ptr = (T*)malloc(num_elements * sizeof(T));
if (t_ptr == nullptr) 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 nullptr when num_elements == 0, non-nullptr otherwise.
*/
template <typename T>
static inline T *CallocT(size_t num_elements)
{
/*
* MorphOS cannot handle 0 elements allocations, or rather that always
* returns nullptr. So we do that for *all* allocations, thus causing it
* to behave the same on all OSes.
*/
if (num_elements == 0) return nullptr;
T *t_ptr = (T*)calloc(num_elements, sizeof(T));
if (t_ptr == nullptr) 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 nullptr when num_elements == 0, non-nullptr otherwise.
*/
template <typename T>
static inline T *ReallocT(T *t_ptr, size_t num_elements)
{
/*
* MorphOS cannot handle 0 elements allocations, or rather that always
* returns nullptr. 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 nullptr;
}
/* Ensure the size does not overflow. */
CheckAllocationConstraints<T>(num_elements);
t_ptr = (T*)realloc(static_cast<void *>(t_ptr), num_elements * sizeof(T));
if (t_ptr == nullptr) 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 */
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