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author | Elijah Newren <newren@gmail.com> | 2020-11-05 00:22:39 +0000 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2020-11-04 17:09:49 -0800 |
commit | b70c82e6edd33aa03afecd52b0265cf1d9762e1b (patch) | |
tree | 7cb46f485783ecbd672b16aa015820764e8349f3 | |
parent | strmap: new utility functions (diff) | |
download | tgif-b70c82e6edd33aa03afecd52b0265cf1d9762e1b.tar.xz |
strmap: add more utility functions
This adds a number of additional convienence functions I want/need:
* strmap_get_size()
* strmap_empty()
* strmap_remove()
* strmap_for_each_entry()
* strmap_get_entry()
I suspect the first four are self-explanatory.
strmap_get_entry() is similar to strmap_get() except that instead of just
returning the void* value that the string maps to, it returns the
strmap_entry that contains both the string and the void* value (or
NULL if the string isn't in the map). This is helpful because it avoids
multiple lookups, e.g. in some cases a caller would need to call:
* strmap_contains() to check that the map has an entry for the string
* strmap_get() to get the void* value
* <do some work to update the value>
* strmap_put() to update/overwrite the value
If the void* pointer returned really is a pointer, then the last step is
unnecessary, but if the void* pointer is just cast to an integer then
strmap_put() will be needed. In contrast, one can call strmap_get_entry()
and then:
* check if the string was in the map by whether the pointer is NULL
* access the value via entry->value
* directly update entry->value
meaning that we can replace two or three hash table lookups with one.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r-- | strmap.c | 20 | ||||
-rw-r--r-- | strmap.h | 34 |
2 files changed, 54 insertions, 0 deletions
@@ -87,6 +87,11 @@ void *strmap_put(struct strmap *map, const char *str, void *data) return old; } +struct strmap_entry *strmap_get_entry(struct strmap *map, const char *str) +{ + return find_strmap_entry(map, str); +} + void *strmap_get(struct strmap *map, const char *str) { struct strmap_entry *entry = find_strmap_entry(map, str); @@ -97,3 +102,18 @@ int strmap_contains(struct strmap *map, const char *str) { return find_strmap_entry(map, str) != NULL; } + +void strmap_remove(struct strmap *map, const char *str, int free_value) +{ + struct strmap_entry entry, *ret; + hashmap_entry_init(&entry.ent, strhash(str)); + entry.key = str; + ret = hashmap_remove_entry(&map->map, &entry, ent, NULL); + if (!ret) + return; + if (free_value) + free(ret->value); + if (map->strdup_strings) + free((char*)ret->key); + free(ret); +} @@ -51,6 +51,12 @@ void strmap_clear(struct strmap *map, int free_values); void *strmap_put(struct strmap *map, const char *str, void *data); /* + * Return the strmap_entry mapped by "str", or NULL if there is not such + * an item in map. + */ +struct strmap_entry *strmap_get_entry(struct strmap *map, const char *str); + +/* * Return the data pointer mapped by "str", or NULL if the entry does not * exist. */ @@ -62,4 +68,32 @@ void *strmap_get(struct strmap *map, const char *str); */ int strmap_contains(struct strmap *map, const char *str); +/* + * Remove the given entry from the strmap. If the string isn't in the + * strmap, the map is not altered. + */ +void strmap_remove(struct strmap *map, const char *str, int free_value); + +/* + * Return how many entries the strmap has. + */ +static inline unsigned int strmap_get_size(struct strmap *map) +{ + return hashmap_get_size(&map->map); +} + +/* + * Return whether the strmap is empty. + */ +static inline int strmap_empty(struct strmap *map) +{ + return strmap_get_size(map) == 0; +} + +/* + * iterate through @map using @iter, @var is a pointer to a type strmap_entry + */ +#define strmap_for_each_entry(mystrmap, iter, var) \ + hashmap_for_each_entry(&(mystrmap)->map, iter, var, ent) + #endif /* STRMAP_H */ |