diff options
| -rw-r--r-- | src/shared/macro.h | 13 | ||||
| -rw-r--r-- | src/test/test-util.c | 19 |
2 files changed, 27 insertions, 5 deletions
diff --git a/src/shared/macro.h b/src/shared/macro.h index 2807bc74e8..e6734804bd 100644 --- a/src/shared/macro.h +++ b/src/shared/macro.h @@ -79,6 +79,9 @@ #define XCONCATENATE(x, y) x ## y #define CONCATENATE(x, y) XCONCATENATE(x, y) +#define UNIQ_T(x, uniq) CONCATENATE(__unique_prefix_, CONCATENATE(x, uniq)) +#define UNIQ __COUNTER__ + /* Rounds up */ #define ALIGN4(l) (((l) + 3) & ~3) @@ -122,13 +125,13 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) { * @ptr: the pointer to the member. * @type: the type of the container struct this is embedded in. * @member: the name of the member within the struct. - * */ -#define container_of(ptr, type, member) \ +#define container_of(ptr, type, member) __container_of(UNIQ, (ptr), type, member) +#define __container_of(uniq, ptr, type, member) \ __extension__ ({ \ - const typeof( ((type *)0)->member ) *__mptr = (ptr); \ - (type *)( (char *)__mptr - offsetof(type,member) ); \ - }) + const typeof( ((type*)0)->member ) *UNIQ_T(A, uniq) = (ptr); \ + (type*)( (char *)UNIQ_T(A, uniq) - offsetof(type,member) ); \ + }) #undef MAX #define MAX(a,b) \ diff --git a/src/test/test-util.c b/src/test/test-util.c index 4d9b28f9c8..795f3a1b3d 100644 --- a/src/test/test-util.c +++ b/src/test/test-util.c @@ -96,6 +96,24 @@ static void test_max(void) { assert_cc(MAXSIZE(char, long) == sizeof(long)); } +static void test_container_of(void) { + struct mytype { + uint8_t pad1[3]; + uint64_t v1; + uint8_t pad2[2]; + uint32_t v2; + } _packed_ myval = { }; + + assert_cc(sizeof(myval) == 17); + assert_se(container_of(&myval.v1, struct mytype, v1) == &myval); + assert_se(container_of(&myval.v2, struct mytype, v2) == &myval); + assert_se(container_of(&container_of(&myval.v2, + struct mytype, + v2)->v1, + struct mytype, + v1) == &myval); +} + static void test_first_word(void) { assert_se(first_word("Hello", "")); assert_se(first_word("Hello", "Hello")); @@ -1218,6 +1236,7 @@ int main(int argc, char *argv[]) { test_streq_ptr(); test_align_power2(); test_max(); + test_container_of(); test_first_word(); test_close_many(); test_parse_boolean(); |