git/strmap.c
Elijah Newren 23a276a9c4 strmap: take advantage of FLEXPTR_ALLOC_STR when relevant
By default, we do not use a mempool and strdup_strings is true; in this
case, we can avoid both an extra allocation and an extra free by just
over-allocating for the strmap_entry leaving enough space at the end to
copy the key.  FLEXPTR_ALLOC_STR exists for exactly this purpose, so
make use of it.

Also, adjust the case when we are using a memory pool and strdup_strings
is true to just do one allocation from the memory pool instead of two so
that the strmap_clear() and strmap_remove() code can just avoid freeing
the key in all cases.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-11 12:55:27 -08:00

179 lines
4.3 KiB
C

#include "git-compat-util.h"
#include "strmap.h"
#include "mem-pool.h"
int cmp_strmap_entry(const void *hashmap_cmp_fn_data,
const struct hashmap_entry *entry1,
const struct hashmap_entry *entry2,
const void *keydata)
{
const struct strmap_entry *e1, *e2;
e1 = container_of(entry1, const struct strmap_entry, ent);
e2 = container_of(entry2, const struct strmap_entry, ent);
return strcmp(e1->key, e2->key);
}
static struct strmap_entry *find_strmap_entry(struct strmap *map,
const char *str)
{
struct strmap_entry entry;
hashmap_entry_init(&entry.ent, strhash(str));
entry.key = str;
return hashmap_get_entry(&map->map, &entry, ent, NULL);
}
void strmap_init(struct strmap *map)
{
strmap_init_with_options(map, NULL, 1);
}
void strmap_init_with_options(struct strmap *map,
struct mem_pool *pool,
int strdup_strings)
{
hashmap_init(&map->map, cmp_strmap_entry, NULL, 0);
map->pool = pool;
map->strdup_strings = strdup_strings;
}
static void strmap_free_entries_(struct strmap *map, int free_values)
{
struct hashmap_iter iter;
struct strmap_entry *e;
if (!map)
return;
if (!free_values && map->pool)
/* Memory other than util is owned by and freed with the pool */
return;
/*
* We need to iterate over the hashmap entries and free
* e->key and e->value ourselves; hashmap has no API to
* take care of that for us. Since we're already iterating over
* the hashmap, though, might as well free e too and avoid the need
* to make some call into the hashmap API to do that.
*/
hashmap_for_each_entry(&map->map, &iter, e, ent) {
if (free_values)
free(e->value);
if (!map->pool)
free(e);
}
}
void strmap_clear(struct strmap *map, int free_values)
{
strmap_free_entries_(map, free_values);
hashmap_clear(&map->map);
}
void strmap_partial_clear(struct strmap *map, int free_values)
{
strmap_free_entries_(map, free_values);
hashmap_partial_clear(&map->map);
}
static struct strmap_entry *create_entry(struct strmap *map,
const char *str,
void *data)
{
struct strmap_entry *entry;
if (map->strdup_strings) {
if (!map->pool) {
FLEXPTR_ALLOC_STR(entry, key, str);
} else {
size_t len = st_add(strlen(str), 1); /* include NUL */
entry = mem_pool_alloc(map->pool,
st_add(sizeof(*entry), len));
memcpy(entry + 1, str, len);
entry->key = (void *)(entry + 1);
}
} else if (!map->pool) {
entry = xmalloc(sizeof(*entry));
} else {
entry = mem_pool_alloc(map->pool, sizeof(*entry));
}
hashmap_entry_init(&entry->ent, strhash(str));
if (!map->strdup_strings)
entry->key = str;
entry->value = data;
return entry;
}
void *strmap_put(struct strmap *map, const char *str, void *data)
{
struct strmap_entry *entry = find_strmap_entry(map, str);
if (entry) {
void *old = entry->value;
entry->value = data;
return old;
}
entry = create_entry(map, str, data);
hashmap_add(&map->map, &entry->ent);
return NULL;
}
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);
return entry ? entry->value : NULL;
}
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->pool)
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);
}
int strset_add(struct strset *set, const char *str)
{
/*
* Cannot use strmap_put() because it'll return NULL in both cases:
* - cannot find str: NULL means "not found"
* - does find str: NULL is the value associated with str
*/
struct strmap_entry *entry = find_strmap_entry(&set->map, str);
if (entry)
return 0;
entry = create_entry(&set->map, str, NULL);
hashmap_add(&set->map.map, &entry->ent);
return 1;
}