OpenCloudOS-Kernel/include/linux/stddef.h

76 lines
2.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_STDDEF_H
#define _LINUX_STDDEF_H
#include <uapi/linux/stddef.h>
#undef NULL
#define NULL ((void *)0)
enum {
false = 0,
true = 1
};
#undef offsetof
#ifdef __compiler_offsetof
#define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE, MEMBER)
#else
#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
#endif
/**
* sizeof_field(TYPE, MEMBER)
*
* @TYPE: The structure containing the field of interest
* @MEMBER: The field to return the size of
*/
#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
/**
* offsetofend(TYPE, MEMBER)
*
* @TYPE: The type of the structure
* @MEMBER: The member within the structure to get the end offset of
*/
#define offsetofend(TYPE, MEMBER) \
(offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER))
/**
* __struct_group() - Create a mirrored named and anonyomous struct
*
* @TAG: The tag name for the named sub-struct (usually empty)
* @NAME: The identifier name of the mirrored sub-struct
* @ATTRS: Any struct attributes (usually empty)
* @MEMBERS: The member declarations for the mirrored structs
*
* Used to create an anonymous union of two structs with identical layout
* and size: one anonymous and one named. The former's members can be used
* normally without sub-struct naming, and the latter can be used to
* reason about the start, end, and size of the group of struct members.
* The named struct can also be explicitly tagged for layer reuse, as well
* as both having struct attributes appended.
*/
#define __struct_group(TAG, NAME, ATTRS, MEMBERS...) \
union { \
struct { MEMBERS } ATTRS; \
struct TAG { MEMBERS } ATTRS NAME; \
}
/**
* struct_group() - Wrap a set of declarations in a mirrored struct
*
* @NAME: The identifier name of the mirrored sub-struct
* @MEMBERS: The member declarations for the mirrored structs
*
* Used to create an anonymous union of two structs with identical
* layout and size: one anonymous and one named. The former can be
* used normally without sub-struct naming, and the latter can be
* used to reason about the start, end, and size of the group of
* struct members.
*/
#define struct_group(NAME, MEMBERS...) \
__struct_group(/* no tag */, NAME, /* no attrs */, MEMBERS)
#endif