hash-table: improve and add additional tests

README.md

@@ -19,11 +19,13 @@ I think `ds` namespace is very good choice, we can use it like this:
 ```
 
 ## Todo
-- [x] rbtree (top-down insertion, top-down deletion)
+- [x] rbtree
+   - [x] top-down insertion
+   - [x] top-down deletion
 - [x] forward-list
 - [x] hash-table
    - [x] builtin hash functions e.g. djb2
-   - [ ] resizing hash table
+   - [x] resizing hash table
 - [ ] octree
 - [ ] quadtree
 

src/hash_table.c

@@ -120,15 +120,16 @@ hash_insert(HTable     *htable,
     return;
   }
 
-  if (!found) {
+  if (!prev) {
     item->next         = htable->table[idx];
     htable->table[idx] = item;
   }
 
   /* there is no need to access array (read + write),
    just append it */
   else {
-    found->next = item;
+    prev->next = item;
+    item->next = NULL;
   }
 
   htable->count++;
@@ -148,6 +149,7 @@ hash_set(HTable *htable,
   }
 
   if (hash_finditem(htable, key, &idx, &found, &prev)) {
+    found->key  = key;
     found->data = value;
     return;
   }
@@ -156,15 +158,15 @@ hash_set(HTable *htable,
   item->key          = key;
   item->data         = value;
 
-  if (!found) {
+  if (!prev) {
     item->next         = htable->table[idx];
     htable->table[idx] = item;
   }
 
   /* there is no need to access array (read + write),
      just append it */
   else {
-    found->next = item;
+    prev->next = item;
   }
 
   htable->count++;

test/src/test_htable.c

@@ -19,17 +19,38 @@ test_htable(void **state) {
   uint32_t count, i, k;
   uint32_t capacity;
 
-  capacity = ds_prime_num(25);
+  capacity = ds_prime_num(3);
   htable   = hash_new_str(capacity);
 
   /* 25 is not a prime number */
-  assert_true(htable->capacity > 25);
+  assert_true(htable->capacity > 3);
 
   count = 1000;
 
   srand((unsigned int)time(NULL));
 
-  /* make sure it is samll size: max 32 */
+  for (i = 0; i < 2; i++) {
+    /* random key length */
+    k = rand() % (sizeof(keybuf) / 8 - 1);
+
+    rand_str(keybuf, k);
+    key = strdup(keybuf);
+
+    hash_set(htable, key, key);
+
+    /* test find value */
+    found = hash_get(htable, key);
+    assert_non_null(found);
+
+    /* found values must be same */
+    assert_ptr_equal(key, found);
+    inserted_items[i] = key;
+  }
+
+  /* increase size */
+  hash_resize(htable, 9);
+  assert_true(htable->count == 2);
+
   for (i = 0; i < count; i++) {
     /* random key length */
     k = rand() % (sizeof(keybuf) / 8 - 1);
@@ -47,8 +68,23 @@ test_htable(void **state) {
     assert_ptr_equal(key, found);
     inserted_items[i] = key;
 
-    if (i == 10 || i == 50) {
+    if (i == 0 || i == 10 || i == 50) {
+      hash_unset(htable, key);
+
+      /* try to unset again */
       hash_unset(htable, key);
+
+      found = hash_get(htable, key);
+      assert_null(found);
+
+      /* allow only once */
+      hash_set(htable, key, key);
+      hash_set(htable, key, key);
+      hash_set(htable, key, key);
+
+      /* test remove by NULL */
+      hash_set(htable, key, NULL);
+
       found = hash_get(htable, key);
       assert_null(found);
     }
@@ -66,7 +102,6 @@ test_htable(void **state) {
   hash_resize(htable, 15);
   assert_true(htable->count == count);
 
-  /* some extra test after resizing table */
   for (i = 0; i < 10; i++) {
     /* random key length */
     k = rand() % (sizeof(keybuf) / 8 - 1);