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Location: cpp/openttd-patchpack/source/src/core/alloc_func.hpp
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(svn r12026) -Update: 'exit' is consistent with UK English in OpenTTD, 'quit' with US English
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/** @file alloc_func.hpp Functions related to the allocation of memory */
#ifndef ALLOC_FUNC_HPP
#define ALLOC_FUNC_HPP
/**
* 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).
* @param 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> 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;
T *t_ptr = (T*)malloc(num_elements * sizeof(T));
if (t_ptr == NULL) error("Out of memory. Cannot allocate %i bytes", 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.
* @param 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> 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) error("Out of memory. Cannot allocate %i bytes", 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 memory contains all zero values.
* @param 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> 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;
}
t_ptr = (T*)realloc(t_ptr, num_elements * sizeof(T));
if (t_ptr == NULL) error("Out of memory. Cannot reallocate %i bytes", num_elements * sizeof(T));
return t_ptr;
}
/**
* A small 'wrapper' for allocations that can be done on most OSes on the
* stack, but are just too large to fit in the stack on devices with a small
* stack such as the NDS.
* So when it is possible a stack allocation is made, otherwise a heap
* allocation is made and this is freed once the struct goes out of scope.
* @param T the type to make the allocation for
* @param length the amount of items to allocate
*/
template <typename T, size_t length>
struct SmallStackSafeStackAlloc {
#if !defined(__NDS__)
/** Storing the data on the stack */
T data[length];
#else
/** Storing it on the heap */
T *data;
/** Allocating the memory */
SmallStackSafeStackAlloc() : data(MallocT<T>(length)) {}
/** And freeing when it goes out of scope */
~SmallStackSafeStackAlloc() { free(data); }
#endif
/**
* Gets a pointer to the data stored in this wrapper.
* @return the pointer.
*/
operator T* () { return data; }
};
#endif /* ALLOC_FUNC_HPP */
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