htable: start empty.

[ccan] / ccan / htable / htable.c

diff --git a/ccan/htable/htable.c b/ccan/htable/htable.c
index 20b6f5ae2dc964c521aa7f517912cd3d4ab9aa6c..ba5f0de530a1a68d7acd5649cfeca6a67e64142b 100644 (file)
--- a/ccan/htable/htable.c
+++ b/ccan/htable/htable.c
@@ -7,9 +7,6 @@
 #include <stdbool.h>
 #include <assert.h>
 
-/* This means a struct htable takes at least 512 bytes / 1k (32/64 bits). */
-#define HTABLE_BASE_BITS 7
-
 /* We use 0x1 as deleted marker. */
 #define HTABLE_DELETED (0x1)
 
@@ -62,29 +59,27 @@ struct htable *htable_new(size_t (*rehash)(const void *elem, void *priv),
 {
        struct htable *ht = malloc(sizeof(struct htable));
        if (ht) {
-               ht->bits = HTABLE_BASE_BITS;
+               ht->bits = 0;
                ht->rehash = rehash;
                ht->priv = priv;
                ht->elems = 0;
                ht->deleted = 0;
-               ht->max = ((size_t)1 << ht->bits) * 3 / 4;
-               ht->max_with_deleted = ((size_t)1 << ht->bits) * 9 / 10;
+               ht->max = 0;
+               ht->max_with_deleted = 0;
                /* This guarantees we enter update_common first add. */
                ht->common_mask = -1;
                ht->common_bits = 0;
                ht->perfect_bit = 0;
-               ht->table = calloc(1 << ht->bits, sizeof(uintptr_t));
-               if (!ht->table) {
-                       free(ht);
-                       ht = NULL;
-               }
+               /* Dummy table until first insert. */
+               ht->table = &ht->perfect_bit;
        }
        return ht;
 }
 
 void htable_free(const struct htable *ht)
 {
-       free((void *)ht->table);
+       if (ht->table != &ht->perfect_bit)
+               free((void *)ht->table);
        free((void *)ht);
 }
 
@@ -169,8 +164,8 @@ static COLD bool double_table(struct htable *ht)
                return false;
        }
        ht->bits++;
-       ht->max *= 2;
-       ht->max_with_deleted *= 2;
+       ht->max = ((size_t)3 << ht->bits) / 4;
+       ht->max_with_deleted = ((size_t)9 << ht->bits) / 10;
 
        /* If we lost our "perfect bit", get it back now. */
        if (!ht->perfect_bit && ht->common_mask) {
@@ -182,14 +177,16 @@ static COLD bool double_table(struct htable *ht)
                }
        }
 
-       for (i = 0; i < oldnum; i++) {
-               if (entry_is_valid(e = oldtable[i])) {
-                       void *p = get_raw_ptr(ht, e);
-                       ht_add(ht, p, ht->rehash(p, ht->priv));
+       if (oldtable != &ht->perfect_bit) {
+               for (i = 0; i < oldnum; i++) {
+                       if (entry_is_valid(e = oldtable[i])) {
+                               void *p = get_raw_ptr(ht, e);
+                               ht_add(ht, p, ht->rehash(p, ht->priv));
+                       }
                }
+               free(oldtable);
        }
        ht->deleted = 0;
-       free(oldtable);
        return true;
 }