#ifndef _LIBALLOC_H
#define _LIBALLOC_H

#include <stddef.h>
#include <stdint.h>

#define _ALLOC_SKIP_DEFINE

// If we are told to not define our own size_t, then we
// skip the define.
#ifndef _ALLOC_SKIP_DEFINE

#ifndef _HAVE_SIZE_T
#define _HAVE_SIZE_T
typedef unsigned int size_t;
#endif

#ifndef NULL
#define NULL 0
#endif

#endif

#ifdef __cplusplus
extern "C" {
#endif

/** This is a boundary tag which is prepended to the
 * page or section of a page which we have allocated. It is
 * used to identify valid memory blocks that the
 * application is trying to free.
 */
struct boundary_tag {
  unsigned int magic;     //< It's a kind of ...
  unsigned int size;      //< Requested size.
  unsigned int real_size; //< Actual size.
  int index;              //< Location in the page table.

  struct boundary_tag* split_left;  //< Linked-list info for broken pages.
  struct boundary_tag* split_right; //< The same.

  struct boundary_tag* next; //< Linked list info.
  struct boundary_tag* prev; //< Linked list info.

  int mem_rid;
};

/** This function is supposed to lock the memory data structures. It
 * could be as simple as disabling interrupts or acquiring a spinlock.
 * It's up to you to decide.
 *
 * \return 0 if the lock was acquired successfully. Anything else is
 * failure.
 */
extern int liballoc_lock (void);

/** This function unlocks what was previously locked by the liballoc_lock
 * function.  If it disabled interrupts, it enables interrupts. If it
 * had acquiried a spinlock, it releases the spinlock. etc.
 *
 * \return 0 if the lock was successfully released.
 */
extern int liballoc_unlock (void);

/** This is the hook into the local system which allocates pages. It
 * accepts an integer parameter which is the number of pages
 * required.  The page size was set up in the liballoc_init function.
 *
 * \return NULL if the pages were not allocated.
 * \return A pointer to the allocated memory.
 */
extern void* liballoc_alloc (int pages, int* mem_rid);

/** This frees previously allocated memory. The void* parameter passed
 * to the function is the exact same value returned from a previous
 * liballoc_alloc call.
 *
 * The integer value is the number of pages to free.
 *
 * \return 0 if the memory was successfully freed.
 */
extern int liballoc_free (void* ptr, int pages, int mem_rid);

void* malloc (size_t);         //< The standard function.
void* realloc (void*, size_t); //< The standard function.
void* calloc (size_t, size_t); //< The standard function.
void free (void*);             //< The standard function.

void liballoc_init (void);
void liballoc_deinit (void);

#ifdef __cplusplus
}
#endif

#endif