| Message ID | c1d217217180cff0b048d5dbac57b8e363db7848.1604343314.git.gitgitgadget@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add struct strmap and associated utility functions | expand |
On Mon, Nov 02, 2020 at 06:55:09PM +0000, Elijah Newren via GitGitGadget wrote: > From: Elijah Newren <newren@gmail.com> > > Although strmap could be used as a string->int map, one either had to > allocate an int for every entry and then deallocate later, or one had to > do a bunch of casting between (void*) and (intptr_t). > > Add some special functions that do the casting. Also, rename put->set > for such wrapper functions since 'put' implied there may be some > deallocation needed if the string was already found in the map, which > isn't the case when we're storing an int value directly in the void* > slot instead of using the void* slot as a pointer to data. > > A note on the name: if anyone has a better name suggestion than > strintmap, I'm happy to take it. It seems slightly unwieldy, but I have > not been able to come up with a better name. You can probably drop this last paragraph. It's good for review, but probably not in the commit message. :) > +void strintmap_incr(struct strintmap *map, const char *str, intptr_t amt) > +{ > + struct strmap_entry *entry = find_strmap_entry(&map->map, str); > + if (entry) { > + intptr_t *whence = (intptr_t*)&entry->value; > + *whence += amt; > + } > + else > + strintmap_set(map, str, map->default_value + amt); > +} Here we use the new default_value. Neat. > diff --git a/strmap.h b/strmap.h > index 10b4642860..31474f781e 100644 > --- a/strmap.h > +++ b/strmap.h > @@ -23,6 +23,11 @@ int cmp_strmap_entry(const void *hashmap_cmp_fn_data, > .map = HASHMAP_INIT(cmp_strmap_entry, NULL), \ > .strdup_strings = 1, \ > } > +#define STRINTMAP_INIT { \ > + .map.map = HASHMAP_INIT(cmp_strmap_entry, NULL), \ > + .map.strdup_strings = 1, \ > + .default_value = 0, \ > + } Re-using STRMAP_INIT would shorten this (and avoid repeating internal details of how strmap works). Like: #define STRINTMAP_INIT { \ .map = STRMAP_INIT, \ .default_value = 0, \ } You can also omit default_value, as the value of any un-mentioned elements will get the usual C zero-initialization. So: #define STRINTMAP_INIT { .map = STRMAP_INIT } would be sufficient (though I don't mind making the .default_value part explicit). It could also be a parameter to the macro, but I suspect it would be rarely used. I don't mind leaving it as something that advanced callers can get from using strintmap_init(). > +/* > + * strintmap: > + * A map of string -> int, typecasting the void* of strmap to an int. > + * > + * Primary differences: > + * 1) Since the void* value is just an int in disguise, there is no value > + * to free. (Thus one fewer argument to strintmap_clear) > + * 2) strintmap_get() returns an int; it also requires an extra parameter to > + * be specified so it knows what value to return if the underlying strmap > + * has not key matching the given string. > + * 3) No strmap_put() equivalent; strintmap_set() and strintmap_incr() > + * instead. > + */ I think (2) here is out-of-date, as we now use map->default_value. > +/* > + * Returns the value for str in the map. If str isn't found in the map, > + * the map's default_value is returned. > + */ > +static inline int strintmap_get(struct strintmap *map, const char *str) > +{ > + struct strmap_entry *result = strmap_get_entry(&map->map, str); > + if (!result) > + return map->default_value; > + return (intptr_t)result->value; > +} And we get to reuse default_value here again. Nice. -Peff
diff --git a/strmap.c b/strmap.c index c410c5241a..0d10a884b5 100644 --- a/strmap.c +++ b/strmap.c @@ -123,3 +123,14 @@ void strmap_remove(struct strmap *map, const char *str, int free_value) free((char*)ret->key); free(ret); } + +void strintmap_incr(struct strintmap *map, const char *str, intptr_t amt) +{ + struct strmap_entry *entry = find_strmap_entry(&map->map, str); + if (entry) { + intptr_t *whence = (intptr_t*)&entry->value; + *whence += amt; + } + else + strintmap_set(map, str, map->default_value + amt); +} diff --git a/strmap.h b/strmap.h index 10b4642860..31474f781e 100644 --- a/strmap.h +++ b/strmap.h @@ -23,6 +23,11 @@ int cmp_strmap_entry(const void *hashmap_cmp_fn_data, .map = HASHMAP_INIT(cmp_strmap_entry, NULL), \ .strdup_strings = 1, \ } +#define STRINTMAP_INIT { \ + .map.map = HASHMAP_INIT(cmp_strmap_entry, NULL), \ + .map.strdup_strings = 1, \ + .default_value = 0, \ + } /* * Initialize the members of the strmap. Any keys added to the strmap will @@ -104,4 +109,95 @@ static inline int strmap_empty(struct strmap *map) var; \ var = hashmap_iter_next_entry_offset(iter, 0)) + +/* + * strintmap: + * A map of string -> int, typecasting the void* of strmap to an int. + * + * Primary differences: + * 1) Since the void* value is just an int in disguise, there is no value + * to free. (Thus one fewer argument to strintmap_clear) + * 2) strintmap_get() returns an int; it also requires an extra parameter to + * be specified so it knows what value to return if the underlying strmap + * has not key matching the given string. + * 3) No strmap_put() equivalent; strintmap_set() and strintmap_incr() + * instead. + */ + +struct strintmap { + struct strmap map; + int default_value; +}; + +#define strintmap_for_each_entry(mystrmap, iter, var) \ + strmap_for_each_entry(&(mystrmap)->map, iter, var) + +static inline void strintmap_init(struct strintmap *map, int default_value) +{ + strmap_init(&map->map); + map->default_value = default_value; +} + +static inline void strintmap_init_with_options(struct strintmap *map, + int default_value, + int strdup_strings) +{ + strmap_init_with_options(&map->map, strdup_strings); + map->default_value = default_value; +} + +static inline void strintmap_clear(struct strintmap *map) +{ + strmap_clear(&map->map, 0); +} + +static inline void strintmap_partial_clear(struct strintmap *map) +{ + strmap_partial_clear(&map->map, 0); +} + +static inline int strintmap_contains(struct strintmap *map, const char *str) +{ + return strmap_contains(&map->map, str); +} + +static inline void strintmap_remove(struct strintmap *map, const char *str) +{ + return strmap_remove(&map->map, str, 0); +} + +static inline int strintmap_empty(struct strintmap *map) +{ + return strmap_empty(&map->map); +} + +static inline unsigned int strintmap_get_size(struct strintmap *map) +{ + return strmap_get_size(&map->map); +} + +/* + * Returns the value for str in the map. If str isn't found in the map, + * the map's default_value is returned. + */ +static inline int strintmap_get(struct strintmap *map, const char *str) +{ + struct strmap_entry *result = strmap_get_entry(&map->map, str); + if (!result) + return map->default_value; + return (intptr_t)result->value; +} + +static inline void strintmap_set(struct strintmap *map, const char *str, + intptr_t v) +{ + strmap_put(&map->map, str, (void *)v); +} + +/* + * Increment the value for str by amt. If str isn't in the map, add it and + * set its value to default_value + amt. + */ +void strintmap_incr(struct strintmap *map, const char *str, intptr_t amt); + #endif /* STRMAP_H */