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libbb/procps: smaller global data for username/groupname cache

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function                                             old     new   delta
get_cached                                           101     133     +32
cache_user_group                                       -       4      +4
get_cached_username                                   17      14      -3
username                                               8       -      -8
groupname                                              8       -      -8
clear_username_cache                                  65      47     -18
------------------------------------------------------------------------------
(add/remove: 1/2 grow/shrink: 1/2 up/down: 36/-37)             Total: -1 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2020-12-30 01:04:56 +01:00
parent b230ff9d8f
commit 89a55972fd
1 changed files with 17 additions and 28 deletions
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45
libbb/procps.c
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@ -21,40 +21,29 @@ typedef struct cache_t {
int size;
} cache_t;
static cache_t username, groupname;
static cache_t *cache_user_group;
static void clear_cache(cache_t *cp)
{
free(cp->cache);
cp->cache = NULL;
cp->size = 0;
}
void FAST_FUNC clear_username_cache(void)
{
clear_cache(&username);
clear_cache(&groupname);
if (cache_user_group) {
free(cache_user_group[0].cache);
free(cache_user_group[1].cache);
free(cache_user_group);
cache_user_group = NULL;
}
}
#if 0 /* more generic, but we don't need that yet */
/* Returns -N-1 if not found. */
/* cp->cache[N] is allocated and must be filled in this case */
static int get_cached(cache_t *cp, uid_t id)
{
int i;
for (i = 0; i < cp->size; i++)
if (cp->cache[i].id == id)
return i;
i = cp->size++;
cp->cache = xrealloc_vector(cp->cache, 2, i);
cp->cache[i++].id = id;
return -i;
}
#endif
static char* get_cached(cache_t *cp, uid_t id,
static char* get_cached(int user_group, uid_t id,
char* FAST_FUNC x2x_utoa(uid_t id))
{
cache_t *cp;
int i;
if (!cache_user_group)
cache_user_group = xzalloc(sizeof(cache_user_group[0]) * 2);
cp = &cache_user_group[user_group];
for (i = 0; i < cp->size; i++)
if (cp->cache[i].id == id)
return cp->cache[i].name;
@ -67,11 +56,11 @@ static char* get_cached(cache_t *cp, uid_t id,
}
const char* FAST_FUNC get_cached_username(uid_t uid)
{
return get_cached(&username, uid, uid2uname_utoa);
return get_cached(0, uid, uid2uname_utoa);
}
const char* FAST_FUNC get_cached_groupname(gid_t gid)
{
return get_cached(&groupname, gid, gid2group_utoa);
return get_cached(1, gid, gid2group_utoa);
}