container.h

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/*
 * Copyright (C) 2014 Freie Universität Berlin
 *               2017 HAW-Hamburg
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */
 
#pragma once
 
#include <stddef.h>
#include <stdint.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* uncrustify gets mightily confused by these macros... */
/* begin{code-style-ignore} */
 
#if __STDC_VERSION__ >= 201112L
#   define container_of(PTR, TYPE, MEMBER) \
        (_Generic((PTR), \
            const __typeof__ (((TYPE *) 0)->MEMBER) *: \
                ((TYPE *) ((uintptr_t) (PTR) - offsetof(TYPE, MEMBER))), \
            __typeof__ (((TYPE *) 0)->MEMBER) *: \
                ((TYPE *) ((uintptr_t) (PTR) - offsetof(TYPE, MEMBER))) \
        ))
#elif defined __GNUC__
#   define container_of(PTR, TYPE, MEMBER) \
        (__extension__ ({ \
            __extension__ const __typeof__ (((TYPE *) 0)->MEMBER) *__m____ = (PTR); \
            ((TYPE *) ((uintptr_t) __m____ - offsetof(TYPE, MEMBER))); \
        }))
#else
#   define container_of(PTR, TYPE, MEMBER) \
        ((TYPE *) ((char *) (PTR) - offsetof(TYPE, MEMBER)))
#   define container_of(PTR, TYPE, MEMBER) \ …
#endif
 
#define index_of(ARRAY, ELEMENT) (((uintptr_t)(ELEMENT) - (uintptr_t)(ARRAY)) / sizeof((ARRAY)[0]))
 
#ifndef ARRAY_SIZE
#define ARRAY_SIZE(a) (sizeof((a)) / sizeof((a)[0]))
#endif
 
#ifdef __cplusplus
}
#endif