#ifndef FREELIST_H
#define FREELIST_H

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

/* Fiddle these around according to your need. Delete or check makefile */
#ifdef FREELIST_NOALIGN
#define ALIGN(x) (x)
#else // FREELIST_NOALIGN

/* Align to nearest multiple of sizeof(void*) */
static inline size_t align_up(size_t n) {
    return (n + sizeof(void *) - 1) & ~(sizeof(void *) - 1);
}

#define ALIGN(x) (align_up(x))
#endif // FREELIST_NOALIGN

typedef struct FreeListBlock {
    struct FreeListBlock *next;
} FreeListBlock;

typedef struct {
    uintptr_t      start;
    uintptr_t      end;
    FreeListBlock *free;
    size_t         size;
    size_t         allocated;
} FreeList;

int    fl_init(FreeList *fl, uintptr_t start, uintptr_t end, size_t itemsize);
int    fl_free(FreeList *fl, void *ptr);
int    fl_is_managed(FreeList *fl, void *ptr);
void  *fl_alloc(FreeList *fl);
size_t fl_check(FreeList *fl);
size_t fl_allocated(FreeList *fl);
size_t fl_available(FreeList *fl);
size_t fl_capacity(FreeList *fl);
float  fl_utilization(FreeList *fl, size_t itemsize);

#endif // FREELIST_H