Switch to offsetof()

4 files changed, 7 insertions, 14 deletions

diff --git a/src/common/container.c b/src/common/container.c
index 689e7e55e9..8645cb4826 100644
--- a/src/common/container.c
+++ b/src/common/container.c
@@ -843,13 +843,13 @@ smartlist_sort_pointers(smartlist_t *sl)
  *   }
  *
  *   void timer_heap_insert(smartlist_t *heap, timer_t *timer) {
- *      smartlist_pqueue_add(heap, compare, STRUCT_OFFSET(timer_t, heap_index),
+ *      smartlist_pqueue_add(heap, compare, offsetof(timer_t, heap_index),
  *         timer);
  *   }
  *
  *   void timer_heap_pop(smartlist_t *heap) {
  *      return smartlist_pqueue_pop(heap, compare,
- *         STRUCT_OFFSET(timer_t, heap_index));
+ *         offsetof(timer_t, heap_index));
  *   }
  */
 
diff --git a/src/common/crypto.c b/src/common/crypto.c
index c258f239a8..4d6a70bc49 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -1884,7 +1884,7 @@ crypto_digest_alloc_bytes(digest_algorithm_t alg)
   /* Helper: returns the number of bytes in the 'f' field of 'st' */
 #define STRUCT_FIELD_SIZE(st, f) (sizeof( ((st*)0)->f ))
   /* Gives the length of crypto_digest_t through the end of the field 'd' */
-#define END_OF_FIELD(f) (STRUCT_OFFSET(crypto_digest_t, f) + \
+#define END_OF_FIELD(f) (offsetof(crypto_digest_t, f) + \
                          STRUCT_FIELD_SIZE(crypto_digest_t, f))
   switch (alg) {
     case DIGEST_SHA1:
diff --git a/src/common/memarea.c b/src/common/memarea.c
index 659d1edf54..4e2a5e5fc5 100644
--- a/src/common/memarea.c
+++ b/src/common/memarea.c
@@ -7,6 +7,7 @@
  */
 
 #include "orconfig.h"
+#include <stddef.h>
 #include <stdlib.h>
 #include "memarea.h"
 #include "util.h"
@@ -101,7 +102,7 @@ typedef struct memarea_chunk_t {
 
 /** How many bytes are needed for overhead before we get to the memory part
  * of a chunk? */
-#define CHUNK_HEADER_SIZE STRUCT_OFFSET(memarea_chunk_t, U_MEM)
+#define CHUNK_HEADER_SIZE offsetof(memarea_chunk_t, U_MEM)
 
 /** What's the smallest that we'll allocate a chunk? */
 #define CHUNK_SIZE 4096
diff --git a/src/common/util.h b/src/common/util.h
index d56abcee2e..df581d2405 100644
--- a/src/common/util.h
+++ b/src/common/util.h
@@ -109,19 +109,11 @@ extern int dmalloc_free(const char *file, const int line, void *pnt,
 
 void tor_log_mallinfo(int severity);
 
-/** Return the offset of <b>member</b> within the type <b>tp</b>, in bytes */
-#if defined(__GNUC__) && __GNUC__ > 3
-#define STRUCT_OFFSET(tp, member) __builtin_offsetof(tp, member)
-#else
- #define STRUCT_OFFSET(tp, member) \
-   ((off_t) (((char*)&((tp*)0)->member)-(char*)0))
-#endif
-
 /** Macro: yield a pointer to the field at position <b>off</b> within the
  * structure <b>st</b>.  Example:
  * <pre>
  *   struct a { int foo; int bar; } x;
- *   off_t bar_offset = STRUCT_OFFSET(struct a, bar);
+ *   off_t bar_offset = offsetof(struct a, bar);
  *   int *bar_p = STRUCT_VAR_P(&x, bar_offset);
  *   *bar_p = 3;
  * </pre>
@@ -138,7 +130,7 @@ void tor_log_mallinfo(int severity);
  * </pre>
  */
 #define SUBTYPE_P(p, subtype, basemember) \
-  ((void*) ( ((char*)(p)) - STRUCT_OFFSET(subtype, basemember) ))
+  ((void*) ( ((char*)(p)) - offsetof(subtype, basemember) ))
 
 /* Logic */
 /** Macro: true if two values have the same boolean value. */