*/
static stat_size_table_t stat_size_new(void) {
return (stat_size_table_t)memset(
- mem_a(sizeof(stat_size_entry_t*) * ST_SIZE),
- 0, ST_SIZE * sizeof(stat_size_entry_t*)
+ mem_a(sizeof(stat_size_entry_t) * ST_SIZE),
+ 0, ST_SIZE * sizeof(stat_size_entry_t)
);
}
size_t hash = (key % ST_SIZE);
while (table[hash] && table[hash]->key != key)
hash = (hash + 1) % ST_SIZE;
- table[hash] = (stat_size_entry_t*)mem_a(sizeof(stat_size_entry_t));
- table[hash]->key = key;
+ table[hash] = (stat_size_entry_t*)mem_a(sizeof(stat_size_entry_t));
+ table[hash]->key = key;
table[hash]->value = value;
}
struct hash_node_t *next; /* next node (linked list) */
} hash_node_t;
+/*
+ * This is a patched version of the Murmur2 hashing function to use
+ * a proper pre-mix and post-mix setup. Infact this is Murmur3 for
+ * the most part just reinvented.
+ *
+ * Murmur 2 contains an inner loop such as:
+ * while (l >= 4) {
+ * u32 k = *(u32*)d;
+ * k *= m;
+ * k ^= k >> r;
+ * k *= m;
+ *
+ * h *= m;
+ * h ^= k;
+ * d += 4;
+ * l -= 4;
+ * }
+ *
+ * The two u32s that form the key are the same value x (pulled from data)
+ * this premix stage will perform the same results for both values. Unrolled
+ * this produces just:
+ * x *= m;
+ * x ^= x >> r;
+ * x *= m;
+ *
+ * h *= m;
+ * h ^= x;
+ * h *= m;
+ * h ^= x;
+ *
+ * This appears to be fine, except what happens when m == 1? well x
+ * cancels out entierly, leaving just:
+ * x ^= x >> r;
+ * h ^= x;
+ * h ^= x;
+ *
+ * So all keys hash to the same value, but how often does m == 1?
+ * well, it turns out testing x for all possible values yeilds only
+ * 172,013,942 unique results instead of 2^32. So nearly ~4.6 bits
+ * are cancelled out on average!
+ *
+ * This means we have a 14.5% (rounded) chance of colliding more, which
+ * results in another bucket/chain for the hashtable.
+ *
+ * We fix it buy upgrading the pre and post mix ssystems to align with murmur
+ * hash 3.
+ */
+#if 1
+#define GMQCC_ROTL32(X, R) (((X) << (R)) | ((X) >> (32 - (R))))
+GMQCC_INLINE size_t util_hthash(hash_table_t *ht, const char *key) {
+ const unsigned char *data = (const unsigned char *)key;
+ const size_t len = strlen(key);
+ const size_t block = len / 4;
+ const uint32_t mask1 = 0xCC9E2D51;
+ const uint32_t mask2 = 0x1B873593;
+ const uint32_t *blocks = (const uint32_t*)(data + block * 4);
+ const unsigned char *tail = (const unsigned char *)(data + block * 4);
+
+ size_t i;
+ uint32_t k;
+ uint32_t h = 0x1EF0 ^ len;
+
+ for (i = -block; i; i++) {
+ k = blocks[i];
+ k *= mask1;
+ k = GMQCC_ROTL32(k, 15);
+ k *= mask2;
+ h ^= k;
+ h = GMQCC_ROTL32(h, 13);
+ h = h * 5 + 0xE6546B64;
+ }
+
+ k = 0;
+ switch (len & 3) {
+ case 3:
+ k ^= tail[2] << 16;
+ case 2:
+ k ^= tail[1] << 8;
+ case 1:
+ k ^= tail[0];
+ k *= mask1;
+ k = GMQCC_ROTL32(k, 15);
+ k *= mask2;
+ h ^= k;
+ }
+
+ h ^= len;
+ h ^= h >> 16;
+ h *= 0x85EBCA6B;
+ h ^= h >> 13;
+ h *= 0xC2B2AE35;
+ h ^= h >> 16;
+
+ return (size_t) (h % ht->size);
+}
+#undef GMQCC_ROTL32
+#else
+/* We keep the old for reference */
GMQCC_INLINE size_t util_hthash(hash_table_t *ht, const char *key) {
const uint32_t mix = 0x5BD1E995;
const uint32_t rot = 24;
return (size_t) (hash % ht->size);
}
+#endif
static hash_node_t *_util_htnewpair(const char *key, void *value) {
hash_node_t *node;
*/
void util_htrem(hash_table_t *ht, void (*callback)(void *data)) {
size_t i = 0;
- for (; i < ht->size; i++) {
+
+ for (; i < ht->size; ++i) {
hash_node_t *n = ht->table[i];
hash_node_t *p;
if (callback)
callback(n->value);
p = n;
- n = n->next;
+ n = p->next;
mem_d(p);
}
}
static void stat_dump_mem_info(void) {
- con_out("Memory information:\n\
+ con_out("Memory Information:\n\
Total allocations: %llu\n\
Total deallocations: %llu\n\
Total allocated: %f (MB)\n\
}
void stat_info() {
- if (OPTS_OPTION_BOOL(OPTION_DEBUG))
- stat_dump_mem_leaks();
-
- if (OPTS_OPTION_BOOL(OPTION_DEBUG) ||
- OPTS_OPTION_BOOL(OPTION_MEMCHK))
- stat_dump_mem_info();
-
if (OPTS_OPTION_BOOL(OPTION_MEMCHK) ||
OPTS_OPTION_BOOL(OPTION_STATISTICS)) {
uint64_t mem = 0;
- con_out("\nAdditional Statistics:\n\
+ con_out("Memory Statistics:\n\
Total vectors allocated: %llu\n\
Total string duplicates: %llu\n\
Total hashtables allocated: %llu\n\
stat_dump_stats_table (
stat_size_vectors,
- " %2u| # of %4u byte vectors: %u\n",
+ " %2u| # of %5u byte vectors: %u\n",
&mem
);
stat_dump_stats_table (
stat_size_hashtables,
- " %2u| # of %4u element hashtables: %u\n",
+ " %2u| # of %5u element hashtables: %u\n",
NULL
);
con_out (
- " Total vector memory: %f (MB)\n",
+ " Total vector memory: %f (MB)\n\n",
(float)(mem) / 1048576.0f
);
}
stat_size_del(stat_size_vectors);
if (stat_size_hashtables)
stat_size_del(stat_size_hashtables);
+
+ if (OPTS_OPTION_BOOL(OPTION_DEBUG) ||
+ OPTS_OPTION_BOOL(OPTION_MEMCHK))
+ stat_dump_mem_info();
+
+ if (OPTS_OPTION_BOOL(OPTION_DEBUG))
+ stat_dump_mem_leaks();
}
#undef ST_SIZE
projects / xonotic / gmqcc.git / blobdiff