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| author | Eric Wong <e@80x24.org> | 2019-10-06 23:30:33 +0000 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2019-10-07 10:20:10 +0900 |
| commit | 973d5eea7455e1053842f7474c8ec34755f3525b (patch) | |
| tree | 4411e81347bf94abe48b80a8bda6c6e9a28de3cf /git-compat-util.h | |
| parent | 26b455f21ed7e0c7b0e4e4e69b5ae48545597020 (diff) | |
| download | git-973d5eea7455e1053842f7474c8ec34755f3525b.tar.gz | |
introduce container_of macro
This macro is popular within the Linux kernel for supporting
intrusive data structures such as linked lists, red-black trees,
and chained hash tables while allowing the compiler to do
type checking.
Later patches will use container_of() to remove the limitation
of "hashmap_entry" being location-dependent. This will complete
the transition to compile-time type checking for the hashmap API.
This macro already exists in our source as "list_entry" in
list.h and making "list_entry" an alias to "container_of"
as the Linux kernel has done is a possibility.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'git-compat-util.h')
| -rw-r--r-- | git-compat-util.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/git-compat-util.h b/git-compat-util.h index 83be89de0a..4cc2c8283a 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -1312,4 +1312,14 @@ void unleak_memory(const void *ptr, size_t len); */ #include "banned.h" +/* + * container_of - Get the address of an object containing a field. + * + * @ptr: pointer to the field. + * @type: type of the object. + * @member: name of the field within the object. + */ +#define container_of(ptr, type, member) \ + ((type *) ((char *)(ptr) - offsetof(type, member))) + #endif |