htable: add htable_copy.

[ccan] / ccan / htable / htable.c

diff --git a/ccan/htable/htable.c b/ccan/htable/htable.c
index 59048dc0ada0df95b23583e0dfbba65d3c96768c..e1d13699ea85811fe2f61adbb1ce4eca942406c8 100644 (file)
--- a/ccan/htable/htable.c
+++ b/ccan/htable/htable.c
@@ -5,6 +5,7 @@
 #include <limits.h>
 #include <stdbool.h>
 #include <assert.h>
+#include <string.h>
 
 /* We use 0x1 as deleted marker. */
 #define HTABLE_DELETED (0x1)
@@ -52,6 +53,13 @@ void htable_init(struct htable *ht,
        ht->table = &ht->perfect_bit;
 }
 
+/* We've changed ht->bits, update ht->max and ht->max_with_deleted */
+static void htable_adjust_capacity(struct htable *ht)
+{
+       ht->max = ((size_t)3 << ht->bits) / 4;
+       ht->max_with_deleted = ((size_t)9 << ht->bits) / 10;
+}
+
 bool htable_init_sized(struct htable *ht,
                       size_t (*rehash)(const void *, void *),
                       void *priv, size_t expect)
@@ -69,9 +77,7 @@ bool htable_init_sized(struct htable *ht,
                ht->table = &ht->perfect_bit;
                return false;
        }
-       ht->max = ((size_t)3 << ht->bits) / 4;
-       ht->max_with_deleted = ((size_t)9 << ht->bits) / 10;
-
+       htable_adjust_capacity(ht);
        return true;
 }
        
@@ -82,6 +88,19 @@ void htable_clear(struct htable *ht)
        htable_init(ht, ht->rehash, ht->priv);
 }
 
+bool htable_copy(struct htable *dst, const struct htable *src)
+{
+       uintptr_t *htable = malloc(sizeof(size_t) << src->bits);
+
+       if (!htable)
+               return false;
+
+       *dst = *src;
+       dst->table = htable;
+       memcpy(dst->table, src->table, sizeof(size_t) << src->bits);
+       return true;
+}
+
 static size_t hash_bucket(const struct htable *ht, size_t h)
 {
        return h & ((1 << ht->bits)-1);
@@ -135,6 +154,17 @@ void *htable_next(const struct htable *ht, struct htable_iter *i)
        return NULL;
 }
 
+void *htable_prev(const struct htable *ht, struct htable_iter *i)
+{
+       for (;;) {
+               if (!i->off)
+                       return NULL;
+               i->off --;
+               if (entry_is_valid(ht->table[i->off]))
+                       return get_raw_ptr(ht, ht->table[i->off]);
+       }
+}
+
 /* This does not expand the hash table, that's up to caller. */
 static void ht_add(struct htable *ht, const void *new, size_t h)
 {
@@ -163,8 +193,7 @@ static COLD bool double_table(struct htable *ht)
                return false;
        }
        ht->bits++;
-       ht->max = ((size_t)3 << ht->bits) / 4;
-       ht->max_with_deleted = ((size_t)9 << ht->bits) / 10;
+       htable_adjust_capacity(ht);
 
        /* If we lost our "perfect bit", get it back now. */
        if (!ht->perfect_bit && ht->common_mask) {