#include "array.h"

#include <stdlib.h>
#include <assert.h>

typedef struct
{
   int   itemcount;
   int   itemsize;
} ArrayHeader;

void
ArrayResize(void** array, int itemcount)
{
   ArrayHeader* head = (ArrayHeader*)*array - 1;
   
   assert(*array);

   head->itemcount = itemcount;
   
   head = realloc(head, head->itemcount * head->itemsize + sizeof(ArrayHeader));

   assert(head);

   *array = head;
}

int
ArrayItemSize(void* array)
{
   return ((ArrayHeader*)array)[-1].itemsize;
}

int
ArrayItemCount(void* array)
{
   return ((ArrayHeader*)array)[-1].itemcount;
}

void*
ArrayCreate(int itemcount, int itemsize)
{
   ArrayHeader* array = malloc(itemcount * itemsize + sizeof(ArrayHeader));

   assert(array);

   array->itemcount = itemcount;
   array->itemsize  = itemsize;

   return (ArrayHeader*)array + 1;
}

void
ArrayDelete(void* array)
{
   assert(array);

   ArrayResize(array, 0);
   
   free((ArrayHeader*)array - 1);
}