/* ref: https://github.com/bbu/userland-slab-allocator */

#ifndef __GNUC__
# error Can be compiled only with GCC.
#endif

#pragma once

#include <stdint.h>
#include <stddef.h>
#include <psp2kern/types.h>

extern const size_t slab_pagesize;

struct slab_header {
    struct slab_header *prev, *next;
    uint64_t slots;
    uintptr_t refcount;
    struct slab_header *page;
    SceUID write_res;
    SceUID exe_res;
    uintptr_t exe_data;
    uint8_t data[] __attribute__((aligned(sizeof(void *))));
};

struct slab_chain {
    size_t itemsize, itemcount;
    size_t slabsize, pages_per_alloc;
    uint64_t initial_slotmask, empty_slotmask;
    uintptr_t alignment_mask;
    struct slab_header *partial, *empty, *full;
    SceUID pid;
};

void slab_init(struct slab_chain *, size_t);
void *slab_alloc(struct slab_chain *, uintptr_t *);
void slab_free(struct slab_chain *, const void *);
void slab_traverse(const struct slab_chain *, void (*)(const void *));
void slab_destroy(const struct slab_chain *);