From f0e63c41139f8982add435536d39aff6f3d4ca98 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Sun, 6 Oct 2019 23:30:35 +0000 Subject: hashmap: use *_entry APIs to wrap container_of Using `container_of' can be verbose and choosing names for intermediate "struct hashmap_entry" pointers is a hard problem. So introduce "*_entry" APIs inspired by similar linked-list APIs in the Linux kernel. Unfortunately, `__typeof__' is not portable C, so we need an extra parameter to specify the type. Signed-off-by: Eric Wong Reviewed-by: Derrick Stolee Signed-off-by: Junio C Hamano --- hashmap.h | 40 ++++++++++++++++++++++++++++++++++------ 1 file changed, 34 insertions(+), 6 deletions(-) (limited to 'hashmap.h') diff --git a/hashmap.h b/hashmap.h index 21bc8aff2b..cd42dcc15c 100644 --- a/hashmap.h +++ b/hashmap.h @@ -55,17 +55,15 @@ * * if (!strcmp("print_all_by_key", action)) { * struct long2string k, *e; - * struct hashmap_entry *ent; * hashmap_entry_init(&k->ent, memhash(&key, sizeof(long))); * k.key = key; * * flags &= ~COMPARE_VALUE; - * ent = hashmap_get(&map, &k, NULL); - * if (ent) { - * e = container_of(ent, struct long2string, ent); + * e = hashmap_get_entry(&map, &k, NULL, struct long2string, ent); + * if (e) { * printf("first: %ld %s\n", e->key, e->value); - * while ((ent = hashmap_get_next(&map, ent))) { - * e = container_of(ent, struct long2string, ent); + * while ((e = hashmap_get_next_entry(&map, e, + * struct long2string, ent))) { * printf("found more: %ld %s\n", e->key, e->value); * } * } @@ -387,6 +385,36 @@ static inline void *hashmap_iter_first(struct hashmap *map, return hashmap_iter_next(iter); } +/* + * returns a @pointer of @type matching @keyvar, or NULL if nothing found. + * @keyvar is a pointer of @type + * @member is the name of the "struct hashmap_entry" field in @type + */ +#define hashmap_get_entry(map, keyvar, keydata, type, member) \ + container_of_or_null(hashmap_get(map, &(keyvar)->member, keydata), \ + type, member) + +#define hashmap_get_entry_from_hash(map, hash, keydata, type, member) \ + container_of_or_null(hashmap_get_from_hash(map, hash, keydata), \ + type, member) +/* + * returns the next equal @type pointer to @var, or NULL if not found. + * @var is a pointer of @type + * @member is the name of the "struct hashmap_entry" field in @type + */ +#define hashmap_get_next_entry(map, var, type, member) \ + container_of_or_null(hashmap_get_next(map, &(var)->member), \ + type, member) + +/* + * iterate @map starting from @var, where @var is a pointer of @type + * and @member is the name of the "struct hashmap_entry" field in @type + */ +#define hashmap_for_each_entry_from(map, var, type, member) \ + for (; \ + var; \ + var = hashmap_get_next_entry(map, var, type, member)) + /* * Disable item counting and automatic rehashing when adding/removing items. * -- cgit v1.2.3