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

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>

1 files changed, 17 insertions, 28 deletions

diff --git a/libbb/procps.c b/libbb/procps.c
index 75969947b..f56b71b21 100644
--- a/libbb/procps.c
+++ b/libbb/procps.c
@@ -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 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;
+        if (cache_user_group) {
+                free(cache_user_group[0].cache);
+                free(cache_user_group[1].cache);
+                free(cache_user_group);
+                cache_user_group = NULL;
+        }
 }
-#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);
 }