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authorJunio C Hamano <gitster@pobox.com>2019-10-15 04:48:01 (GMT)
committerJunio C Hamano <gitster@pobox.com>2019-10-15 04:48:02 (GMT)
commit5efabc7ed9e57bb73159d1ad7739c508167ef24a (patch)
tree9e7de3dfe38dcb92614d11613976d32151925ea2 /git-compat-util.h
parentd0ce4d9024882b5363141288979ea3689eab9998 (diff)
parente2b5038d8793a1d1f92b62dab82acc0d6b7dbcb7 (diff)
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Merge branch 'ew/hashmap'
Code clean-up of the hashmap API, both users and implementation. * ew/hashmap: hashmap_entry: remove first member requirement from docs hashmap: remove type arg from hashmap_{get,put,remove}_entry OFFSETOF_VAR macro to simplify hashmap iterators hashmap: introduce hashmap_free_entries hashmap: hashmap_{put,remove} return hashmap_entry * hashmap: use *_entry APIs for iteration hashmap_cmp_fn takes hashmap_entry params hashmap_get{,_from_hash} return "struct hashmap_entry *" hashmap: use *_entry APIs to wrap container_of hashmap_get_next returns "struct hashmap_entry *" introduce container_of macro hashmap_put takes "struct hashmap_entry *" hashmap_remove takes "const struct hashmap_entry *" hashmap_get takes "const struct hashmap_entry *" hashmap_add takes "struct hashmap_entry *" hashmap_get_next takes "const struct hashmap_entry *" hashmap_entry_init takes "struct hashmap_entry *" packfile: use hashmap_entry in delta_base_cache_entry coccicheck: detect hashmap_entry.hash assignment diff: use hashmap_entry_init on moved_entry.ent
Diffstat (limited to 'git-compat-util.h')
-rw-r--r--git-compat-util.h38
1 files changed, 38 insertions, 0 deletions
diff --git a/git-compat-util.h b/git-compat-util.h
index a8b5854..8b8b29a 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -1313,4 +1313,42 @@ 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)))
+
+/*
+ * helper function for `container_of_or_null' to avoid multiple
+ * evaluation of @ptr
+ */
+static inline void *container_of_or_null_offset(void *ptr, size_t offset)
+{
+ return ptr ? (char *)ptr - offset : NULL;
+}
+
+/*
+ * like `container_of', but allows returned value to be NULL
+ */
+#define container_of_or_null(ptr, type, member) \
+ (type *)container_of_or_null_offset(ptr, offsetof(type, member))
+
+/*
+ * like offsetof(), but takes a pointer to a a variable of type which
+ * contains @member, instead of a specified type.
+ * @ptr is subject to multiple evaluation since we can't rely on __typeof__
+ * everywhere.
+ */
+#if defined(__GNUC__) /* clang sets this, too */
+#define OFFSETOF_VAR(ptr, member) offsetof(__typeof__(*ptr), member)
+#else /* !__GNUC__ */
+#define OFFSETOF_VAR(ptr, member) \
+ ((uintptr_t)&(ptr)->member - (uintptr_t)(ptr))
+#endif /* !__GNUC__ */
+
#endif