a8d7d971b1
This is the version of CCAN which CLN was using at the time these were taken. Unfortunately lots of whitespace has been changed, but AFAICT no source changes. Here's the command I ran (with ../ccan checked out to 1ae4c432): ``` make update-ccan CCAN_NEW="alignof array_size build_assert check_type container_of cppmagic likely list mem short_types str structeq take tal tal/str typesafe_cb utf8 endian crypto/sha256" ``` Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: William Casarin <jb55@jb55.com>
146 lines
4.2 KiB
C
146 lines
4.2 KiB
C
/* CC0 (Public domain) - see LICENSE file for details */
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#ifndef CCAN_CONTAINER_OF_H
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#define CCAN_CONTAINER_OF_H
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#include <stddef.h>
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#include "config.h"
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#include <ccan/check_type/check_type.h>
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/**
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* container_of - get pointer to enclosing structure
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* @member_ptr: pointer to the structure member
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* @containing_type: the type this member is within
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* @member: the name of this member within the structure.
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*
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* Given a pointer to a member of a structure, this macro does pointer
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* subtraction to return the pointer to the enclosing type.
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*
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* Example:
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* struct foo {
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* int fielda, fieldb;
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* // ...
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* };
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* struct info {
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* int some_other_field;
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* struct foo my_foo;
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* };
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*
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* static struct info *foo_to_info(struct foo *foo)
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* {
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* return container_of(foo, struct info, my_foo);
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* }
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*/
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#define container_of(member_ptr, containing_type, member) \
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((containing_type *) \
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((char *)(member_ptr) \
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- container_off(containing_type, member)) \
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+ check_types_match(*(member_ptr), ((containing_type *)0)->member))
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/**
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* container_of_or_null - get pointer to enclosing structure, or NULL
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* @member_ptr: pointer to the structure member
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* @containing_type: the type this member is within
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* @member: the name of this member within the structure.
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*
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* Given a pointer to a member of a structure, this macro does pointer
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* subtraction to return the pointer to the enclosing type, unless it
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* is given NULL, in which case it also returns NULL.
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*
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* Example:
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* struct foo {
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* int fielda, fieldb;
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* // ...
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* };
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* struct info {
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* int some_other_field;
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* struct foo my_foo;
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* };
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*
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* static struct info *foo_to_info_allowing_null(struct foo *foo)
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* {
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* return container_of_or_null(foo, struct info, my_foo);
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* }
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*/
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static inline char *container_of_or_null_(void *member_ptr, size_t offset)
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{
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return member_ptr ? (char *)member_ptr - offset : NULL;
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}
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#define container_of_or_null(member_ptr, containing_type, member) \
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((containing_type *) \
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container_of_or_null_(member_ptr, \
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container_off(containing_type, member)) \
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+ check_types_match(*(member_ptr), ((containing_type *)0)->member))
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/**
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* container_off - get offset to enclosing structure
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* @containing_type: the type this member is within
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* @member: the name of this member within the structure.
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*
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* Given a pointer to a member of a structure, this macro does
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* typechecking and figures out the offset to the enclosing type.
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*
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* Example:
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* struct foo {
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* int fielda, fieldb;
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* // ...
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* };
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* struct info {
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* int some_other_field;
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* struct foo my_foo;
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* };
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*
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* static struct info *foo_to_info(struct foo *foo)
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* {
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* size_t off = container_off(struct info, my_foo);
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* return (void *)((char *)foo - off);
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* }
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*/
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#define container_off(containing_type, member) \
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offsetof(containing_type, member)
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/**
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* container_of_var - get pointer to enclosing structure using a variable
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* @member_ptr: pointer to the structure member
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* @container_var: a pointer of same type as this member's container
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* @member: the name of this member within the structure.
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*
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* Given a pointer to a member of a structure, this macro does pointer
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* subtraction to return the pointer to the enclosing type.
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*
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* Example:
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* static struct info *foo_to_i(struct foo *foo)
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* {
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* struct info *i = container_of_var(foo, i, my_foo);
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* return i;
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* }
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*/
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#if HAVE_TYPEOF
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#define container_of_var(member_ptr, container_var, member) \
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container_of(member_ptr, typeof(*container_var), member)
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#else
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#define container_of_var(member_ptr, container_var, member) \
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((void *)((char *)(member_ptr) - \
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container_off_var(container_var, member)))
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#endif
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/**
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* container_off_var - get offset of a field in enclosing structure
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* @container_var: a pointer to a container structure
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* @member: the name of a member within the structure.
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*
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* Given (any) pointer to a structure and a its member name, this
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* macro does pointer subtraction to return offset of member in a
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* structure memory layout.
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*
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*/
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#if HAVE_TYPEOF
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#define container_off_var(var, member) \
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container_off(typeof(*var), member)
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#else
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#define container_off_var(var, member) \
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((const char *)&(var)->member - (const char *)(var))
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#endif
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#endif /* CCAN_CONTAINER_OF_H */
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