mem_allocator.h

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#ifndef MEM_ALLOCATOR_H
#define MEM_ALLOCATOR_H
 
#include "base/base_macros.h"
#include "base/base_types.h"
 
C_LINKAGE_BEGIN


typedef enum MemAllocMode {
    MEM_ALLOC_MODE_ALLOC,   
    MEM_ALLOC_MODE_FREE,    
    MEM_ALLOC_MODE_REALLOC, 
    MEM_ALLOC_MODE_FREE_ALL 
} MemAllocMode;

typedef void *(*MemAllocFn)(MemAllocMode mode, void *ctx, usize size, void *old_ptr);

typedef struct MemAllocator {
    MemAllocFn fn; 
    void *ctx; 
} MemAllocator;


function inline void *
mem_alloc(MemAllocator *alloc, usize size)
{
    return alloc->fn(MEM_ALLOC_MODE_ALLOC, alloc->ctx, size, NULL);
}

function inline void *
mem_realloc(MemAllocator *alloc, void *old_ptr, usize old_size, usize new_size)
{
    // A proper realloc implementation using the vtable
    void *new_ptr = alloc->fn(MEM_ALLOC_MODE_REALLOC, alloc->ctx, new_size, old_ptr);
    if (new_ptr != NULL && new_ptr != old_ptr) {
        MEM_COPY(new_ptr, old_ptr, MIN(old_size, new_size));
        if (old_size > 0) {
            alloc->fn(MEM_ALLOC_MODE_FREE, alloc->ctx, old_size, old_ptr);
        }
    }
    return new_ptr;
}

function inline void
mem_free(MemAllocator *alloc, void *ptr, usize size)
{
    alloc->fn(MEM_ALLOC_MODE_FREE, alloc->ctx, size, ptr);
}

function inline void
mem_free_all(MemAllocator *alloc)
{
    alloc->fn(MEM_ALLOC_MODE_FREE_ALL, alloc->ctx, 0, NULL);
}



#define MAKE(type, count, alloc) ((type *)mem_alloc((alloc), sizeof(type) * (count)))

#define MAKE_STRUCT(type, alloc) ((type *)mem_alloc((alloc), sizeof(type)))

#define RELEASE(type, count, ptr, alloc) mem_free((alloc), (ptr), sizeof(type) * (count))

 
C_LINKAGE_END
 
#endif // MEM_ALLOCATOR_H