mirror of https://github.com/OpenTTD/OpenTTD.git
116 lines
4.0 KiB
C++
116 lines
4.0 KiB
C++
/* $Id$ */
|
|
|
|
/** @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 */
|