#pragma once

/*!
# toy_memory.h

This header defines all of the memory management utilities. Any and all heap-based memory management goes through these utilities.

A default memory allocator function is used internally, but it can be overwritten for diagnostic and platform related purposes.
!*/

#include "toy_common.h"

/*!
## Defined Macros
!*/

/*!
### TOY_GROW_CAPACITY(capacity)

This macro calculates, in place, what size of memory should be allocated based on the previous size.
!*/
#define TOY_GROW_CAPACITY(capacity) 						((capacity) < 8 ? 8 : (capacity) * 2)

/*!
### TOY_GROW_CAPACITY_FAST(capacity)

This macro calculates, in place, what size of memory should be allocated based on the previous size. It grows faster than `TOY_GROW_CAPACITY`.
!*/
#define TOY_GROW_CAPACITY_FAST(capacity)					((capacity) < 32 ? 32 : (capacity) * 2)

/*
### TOY_ALLOCATE(type, count)

This macro wraps `Toy_reallocate()`, which itself calls the allocator function. `type` is the type that will be allocated, and `count` is the number which will be needed (usually calculated with `TOY_GROW_CAPACITY`).

This returns a pointer of `type`.
*/
#define TOY_ALLOCATE(type, count)							((type*)Toy_reallocate(NULL, 0, sizeof(type) * (count)))

/*!
### TOY_FREE(type, pointer)

This macro wraps `Toy_reallocate()`, which itself calls the allocator function. `type` is the type that will be freed, and `pointer` is to what is being freed. This should only be used when a single element has been allocated, as opposed to an array.
!*/
#define TOY_FREE(type, pointer)								Toy_reallocate(pointer, sizeof(type), 0)

/*!
### TOY_FREE_ARRAY(type, pointer, oldCount)

This macro wraps `Toy_reallocate()`, which itself calls the allocator function. `type` is the type that will be freed, `pointer` is a reference to what is being freed, and `oldCount` is the size of the array being freed. This should only be used when an array has been allocated, as opposed to a single element.
!*/
#define TOY_FREE_ARRAY(type, pointer, oldCount)				Toy_reallocate((type*)pointer, sizeof(type) * (oldCount), 0)

/*!
### TOY_GROW_ARRAY(type, pointer, oldCount, count)

This macro wraps `Toy_reallocate()`, which itself calls the allocator function. `type` is the type that is being operated on, `pointer` is what is being resized, `oldCount` is the previous size of the array and `count` is the new size of the array (usually calculated with `TOY_GROW_CAPACITY`).

This returns a pointer of `type`.
!*/
#define TOY_GROW_ARRAY(type, pointer, oldCount, count)		(type*)Toy_reallocate((type*)pointer, sizeof(type) * (oldCount), sizeof(type) * (count))

/*!
### TOY_SHRINK_ARRAY(type, pointer, oldCount, count)

This macro wraps `Toy_reallocate()`, which itself calls the allocator function. `type` is the type that is being operated on, `pointer` is what is being resized, `oldCount` is the previous size of the array and `count` is the new size of the array.

This returns a pointer of `type`.
!*/
#define TOY_SHRINK_ARRAY(type, pointer, oldCount, count)	(type*)Toy_reallocate((type*)pointer, sizeof(type) * (oldCount), sizeof(type) * (count))

/*!
## Defined Interfaces
!*/

/*!
### typedef void* (*Toy_MemoryAllocatorFn)(void* pointer, size_t oldSize, size_t newSize)

This function interface is used for defining any memory allocator functions.

Any and all memory allocator functions should:

* Take a `pointer` to a previously allocated block of memory, or `NULL`
* Take the `oldSize`, which is the previous size of the `pointer` allocated, in bytes (`oldSize` can be 0)
* Take the `newSize`, which is the new size of the buffer to be allocaated, in bytes (`newSize` can be 0)
* Return the newly allocated buffer, or `NULL` if `newSize` is zero
* Return `NULL` on error
!*/

typedef void* (*Toy_MemoryAllocatorFn)(void* pointer, size_t oldSize, size_t newSize);

/*!
## Defined Functions
!*/

/*!
### TOY_API void* Toy_reallocate(void* pointer, size_t oldSize, size_t newSize)

This function shouldn't be called directly. Instead, use one of the given macros.

This function wraps a call to the internal assigned memory allocator.
!*/
TOY_API void* Toy_reallocate(void* pointer, size_t oldSize, size_t newSize);

/*!
### void Toy_setMemoryAllocator(Toy_MemoryAllocatorFn)

This function sets the memory allocator, replacing the default memory allocator.

This function also overwrites any given refstring and reffunction memory allocators, see [toy_refstring.h](toy_refstring_h.md).
!*/
TOY_API void Toy_setMemoryAllocator(Toy_MemoryAllocatorFn);