Cuckoo hash update

* add a destructor function for elements
 * rename cuckoo_free to cuckoo_delete to be consistent with the rest

src/lib/cuckoo.c

@@ -52,6 +52,8 @@ struct cuckoo_struct
 
   enum compact_state autocompact;
   size_t elements;
+
+  cuckoo_dtorfunc dtor;
 };
 
 
@@ -68,7 +70,8 @@ cuckoo_init (Cuckoo self,
              cuckoo_hashfunc h3,
              cuckoo_cmpfunc cmp,
              size_t itemsize,
-             unsigned startsize)
+             unsigned startsize,
+             cuckoo_dtorfunc dtor)
 {
   if (!self)
     return NULL;
@@ -101,6 +104,8 @@ cuckoo_init (Cuckoo self,
 
   self->autocompact = COMPACTING_AUTO;
   self->elements = 0;
+
+  self->dtor = dtor;
   return self;
 }
 
@@ -110,10 +115,11 @@ cuckoo_new (cuckoo_hashfunc h1,
             cuckoo_hashfunc h3,
             cuckoo_cmpfunc cmp,
             size_t itemsize,
-            unsigned startsize)
+            unsigned startsize,
+            cuckoo_dtorfunc dtor)
 {
   Cuckoo self = malloc (sizeof (struct cuckoo_struct));
-  if (!cuckoo_init (self, h1, h2, h3, cmp, itemsize, startsize))
+  if (!cuckoo_init (self, h1, h2, h3, cmp, itemsize, startsize, dtor))
     {
       free (self);
       return NULL;
@@ -126,6 +132,18 @@ cuckoo_destroy (Cuckoo self)
 {
   if (self)
     {
+
+      if (self->dtor)
+        {
+          void* elem;
+          for (elem = self->t1; elem < self->t1 + self->size * 4; elem += self->size)
+            self->dtor (elem);
+          for (elem = self->t2; elem < self->t1 + self->size * 2; elem += self->size)
+            self->dtor (elem);
+          for (elem = self->t3; elem < self->t1 + self->size; elem += self->size)
+            self->dtor (elem);
+        }
+
       free (self->t1);
       free (self->t2);
       free (self->t3);
@@ -135,7 +153,7 @@ cuckoo_destroy (Cuckoo self)
 
 
 void
-cuckoo_free (Cuckoo self)
+cuckoo_delete (Cuckoo self)
 {
   free (cuckoo_destroy (self));
 }
@@ -486,6 +504,9 @@ cuckoo_remove (Cuckoo self, void* item)
 {
   if (item)
     {
+      if (self->dtor)
+        self->dtor (item);
+
       memset (item, 0, self->itemsize);
       --self->elements;
 

src/lib/cuckoo.h

@@ -54,6 +54,14 @@ typedef size_t (*cuckoo_hashfunc)(const void* item, const uint32_t r);
  */
 typedef int (*cuckoo_cmpfunc)(const void* item1, const void* item2);
 
+/**
+ * Item destructor function.
+ * User supplied destructor function. This function is called when items are removed
+ * from the hash or at hash detroy/delete time. Must be safe to be called on a zeroed element.
+ * @param item address of the item to be destroyed
+ */
+typedef void (*cuckoo_dtorfunc)(void* item);
+
 /**
  * Initialize a cuckoo hash.
  * @param self pointer to a uninitialized cuckoo datastructure
@@ -62,6 +70,7 @@ typedef int (*cuckoo_cmpfunc)(const void* item1, const void* item2);
  * @param h3 hash function for the third table
  * @param cmp function which compares two keys
  * @param startsize initial size of table t3, as 2's exponent
+ * @param dtor a function used to clean up hash entries, might be NULL if nothing required
  * @return The initialized hashtable or NULL at allocation failure
  */
 Cuckoo
@@ -71,7 +80,8 @@ cuckoo_init (Cuckoo self,
              cuckoo_hashfunc h3,
              cuckoo_cmpfunc cmp,
              size_t itemsize,
-             unsigned startsize);
+             unsigned startsize,
+             cuckoo_dtorfunc dtor);
 
 /**
  * Allocate a new cuckoo hash.
@@ -80,6 +90,7 @@ cuckoo_init (Cuckoo self,
  * @param h3 hash function for the third table
  * @param cmp function which compares two keys
  * @param startsize initial size of table t3, as 2's exponent
+ * @param dtor a function used to clean up hash entries, might be NULL if nothing required
  * @return The initialized hashtable or NULL at allocation failure
  */
 Cuckoo
@@ -88,7 +99,8 @@ cuckoo_new (cuckoo_hashfunc h1,
             cuckoo_hashfunc h3,
             cuckoo_cmpfunc cmp,
             size_t itemsize,
-            unsigned startsize);
+            unsigned startsize,
+            cuckoo_dtorfunc dtor);
 
 /**
  * Destroy a cuckoo hash.
@@ -104,7 +116,7 @@ cuckoo_destroy (Cuckoo self);
  * @param self handle of the hash table to be freed
  */
 void
-cuckoo_free (Cuckoo self);
+cuckoo_delete (Cuckoo self);
 
 /**
  * Get the number of elements stored in a hash.