[PATCH v1 3/4] hashmap: add simplified hashmap_get_from_hash() API
- From
Karsten Blees <karsten.blees@gmail.com>
- Date
- Jul 2, 2014, 22:22 UTC
- Message-ID
- <53B48613.60509@gmail.com>
- In-Reply-To
- <53B48540.5070600@gmail.com>
Hashmap entries are typically looked up by just a key. The hashmap_get() API expects an initialized entry structure instead, to support compound keys. This flexibility is currently only needed by find_dir_entry() in name-hash.c (and compat/win32/fscache.c in the msysgit fork). All other (currently five) call sites of hashmap_get() have to set up a near emtpy entry structure, resulting in duplicate code like this:
struct hashmap_entry keyentry; hashmap_entry_init(&keyentry, hash(key)); return hashmap_get(map, &keyentry, key);
Add a hashmap_get_from_hash() API that allows hashmap lookups by just specifying the key and its hash code, i.e.:
return hashmap_get_from_hash(map, hash(key), key);
Signed-off-by: Karsten Blees <blees@dcon.de> --- Documentation/technical/api-hashmap.txt | 14 ++++++++++++++ builtin/describe.c | 4 +--- diffcore-rename.c | 7 +++---- hashmap.h | 8 ++++++++ name-hash.c | 5 ++--- test-hashmap.c | 11 +++-------- 6 files changed, 31 insertions(+), 18 deletions(-)
diff --git a/Documentation/technical/api-hashmap.txt b/Documentation/technical/api-hashmap.txt index dc21a7c..f9215d6 100644 --- a/Documentation/technical/api-hashmap.txt +++ b/Documentation/technical/api-hashmap.txt @@ -118,6 +118,20 @@ hashmap_entry) that has at least been initialized with the proper hash code If an entry with matching hash code is found, `key` and `keydata` are passed to `hashmap_cmp_fn` to decide whether the entry matches the key. +`void *hashmap_get_from_hash(const struct hashmap *map, unsigned int hash, const void *keydata)`:: + + Returns the hashmap entry for the specified hash code and key data, + or NULL if not found. ++ +`map` is the hashmap structure. ++ +`hash` is the hash code of the entry to look up. ++ +If an entry with matching hash code is found, `keydata` is passed to +`hashmap_cmp_fn` to decide whether the entry matches the key. The +`entry_or_key` parameter points to a bogus hashmap_entry structure that +should not be used in the comparison. + `void *hashmap_get_next(const struct hashmap *map, const void *entry)`:: Returns the next equal hashmap entry, or NULL if not found. This can be diff --git a/builtin/describe.c b/builtin/describe.c index 57e84c8..ee6a3b9 100644 --- a/builtin/describe.c +++ b/builtin/describe.c @@ -58,9 +58,7 @@ static int commit_name_cmp(const struct commit_name *cn1, static inline struct commit_name *find_commit_name(const unsigned char *peeled) { - struct commit_name key; - hashmap_entry_init(&key, sha1hash(peeled)); - return hashmap_get(&names, &key, peeled); + return hashmap_get_from_hash(&names, sha1hash(peeled), peeled); } static int replace_name(struct commit_name *e, diff --git a/diffcore-rename.c b/diffcore-rename.c index 6fa97d4..2e44a37 100644 --- a/diffcore-rename.c +++ b/diffcore-rename.c @@ -257,15 +257,14 @@ static int find_identical_files(struct hashmap *srcs, int renames = 0; struct diff_filespec *target = rename_dst[dst_index].two; - struct file_similarity *p, *best, dst; + struct file_similarity *p, *best = NULL; int i = 100, best_score = -1; /* * Find the best source match for specified destination. */ - best = NULL; - hashmap_entry_init(&dst, hash_filespec(target)); - for (p = hashmap_get(srcs, &dst, NULL); p; p = hashmap_get_next(srcs, p)) { + p = hashmap_get_from_hash(srcs, hash_filespec(target), NULL); + for (; p; p = hashmap_get_next(srcs, p)) { int score; struct diff_filespec *source = p->filespec; diff --git a/hashmap.h b/hashmap.h index ed5425a..12f0668 100644 --- a/hashmap.h +++ b/hashmap.h @@ -68,6 +68,14 @@ extern void *hashmap_put(struct hashmap *map, void *entry); extern void *hashmap_remove(struct hashmap *map, const void *key, const void *keydata); +static inline void *hashmap_get_from_hash(const struct hashmap *map, + unsigned int hash, const void *keydata) +{ + struct hashmap_entry key; + hashmap_entry_init(&key, hash); + return hashmap_get(map, &key, keydata); +} + /* hashmap_iter functions */ extern void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter); diff --git a/name-hash.c b/name-hash.c index 49fd508..702cd05 100644 --- a/name-hash.c +++ b/name-hash.c @@ -213,12 +213,11 @@ struct cache_entry *index_dir_exists(struct index_state *istate, const char *nam struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase) { struct cache_entry *ce; - struct hashmap_entry key; lazy_init_name_hash(istate); - hashmap_entry_init(&key, memihash(name, namelen)); - ce = hashmap_get(&istate->name_hash, &key, NULL); + ce = hashmap_get_from_hash(&istate->name_hash, + memihash(name, namelen), NULL); while (ce) { if (same_name(ce, name, namelen, icase)) return ce; diff --git a/test-hashmap.c b/test-hashmap.c index f5183fb..3c9f67b 100644 --- a/test-hashmap.c +++ b/test-hashmap.c @@ -115,9 +115,8 @@ static void perf_hashmap(unsigned int method, unsigned int rounds) for (j = 0; j < rounds; j++) { for (i = 0; i < TEST_SIZE; i++) { - struct hashmap_entry key; - hashmap_entry_init(&key, hashes[i]); - hashmap_get(&map, &key, entries[i]->key); + hashmap_get_from_hash(&map, hashes[i], + entries[i]->key); } } @@ -199,12 +198,8 @@ int main(int argc, char *argv[]) } else if (!strcmp("get", cmd) && l1) { - /* setup static key */ - struct hashmap_entry key; - hashmap_entry_init(&key, hash); - /* lookup entry in hashmap */ - entry = hashmap_get(&map, &key, p1); + entry = hashmap_get_from_hash(&map, hash, p1); /* print result */ if (!entry)
-- 1.9.4.msysgit.0.dirty