31 lines
1.1 KiB
C
31 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* adaptation of Linux kernel's <linux/container_of.h>
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*/
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#ifndef _BR_CONTAINER_OF_H
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#define _BR_CONTAINER_OF_H
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/* Are two types/vars the same type (ignoring qualifiers)? */
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#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
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/**
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* typeof_member -
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*/
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#define typeof_member(T, m) typeof(((T*)0)->m)
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/**
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* container_of - cast a member of a structure out to the containing structure
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* @ptr: the pointer to the member.
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* @type: the type of the container struct this is embedded in.
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* @member: the name of the member within the struct.
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*
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*/
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#define container_of(ptr, type, member) ({ \
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void *__mptr = (void *)(ptr); \
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_Static_assert(__same_type(*(ptr), ((type *)0)->member) || \
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__same_type(*(ptr), void), \
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"pointer type mismatch in container_of()"); \
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((type *)(__mptr - offsetof(type, member))); })
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#endif /* BR_CONTAINER_OF_H */
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