refc.h

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/*
 * TARFS - Immutable (read-only) filesystem for embedded systems.
 *
 * Copyright (c) 2026 Viacheslav Logunov
 * SPDX-License-Identifier: MMIT
 *
 * Author:
 *   Viacheslav Logunov <vvb333007@gmail.com>
 *
 * Project:
 *   https://github.com/vvb333007/tarfs
 *
 * @file refc.h
 * @brief Public Atomic Reference Counter API
 */
 

 
#pragma once
 
/* Compilation issues (C / C++): these two languages use different atomic libraries, with different
 * syntax. This is completely safe, as C++ code does not touch tarfs atomics
 */
#ifdef __cplusplus
#  undef _Atomic
#  define _Atomic(X) X
#endif
 

typedef unsigned int refc_type_t;

typedef _Atomic(refc_type_t) refc_t;
 
 
#ifndef __cplusplus
 
#include <stdint.h>
#include <stdatomic.h>
#include <stdlib.h>
#include <stdbool.h>
 

static inline void initref(refc_t *ref) {
 
  if (ref != NULL)
    atomic_init(ref, 1);
}
 

static inline void initrefn(refc_t *ref, refc_type_t n) {
 
  if (ref != NULL)
    atomic_init(ref, n);
}
 
 

refc_type_t addrefn(refc_t *ref, refc_type_t n);
 

static inline refc_type_t addref(refc_t *ref) {
 
  return addrefn(ref, 1);
}

refc_type_t unrefxn(refc_t *r,
             void *object,
             refc_type_t n,
             void (*dtor)(void *));
 
 

static inline refc_type_t unref(refc_t *ref, void *object) {
 
  return unrefxn(ref, object, 1, free);
}

static inline refc_type_t unrefn(refc_t *ref, void *object, refc_type_t n) {
 
  return unrefxn(ref, object, n, free);
}

static inline refc_type_t unrefx(refc_t *ref, void *object, void (*dtor)(void *)) {
 
  return unrefxn(ref, object, 1, dtor);
}

static inline refc_type_t readref(refc_t *r) {
 
    return r ? atomic_load_explicit(r, memory_order_relaxed) : 0;
}
 
#endif /* not __cplusplus */