Add and implement a hash table.

include/ht.h

@@ -0,0 +1,39 @@
+#ifndef LIBDS_HT_HEADER
+#define LIBDS_HT_HEADER
+
+#define LIBDS_HT_SIZE 32
+
+#include "libds.h"
+
+struct ht_node_s {
+    void* key;
+    void* data;
+    struct ht_node_s*  next;
+};
+
+struct ht_s {
+    struct ht_node_s* data[LIBDS_HT_SIZE];
+    unsigned int (*hash_func)(void*);
+    int (*cmp_func)(void*, void*);
+    void* (*copy_func)(void*);
+    void (*free_func)(void*);
+};
+
+typedef struct ht_node_s ht_node;
+typedef struct ht_s ht;
+
+unsigned int ht_default_hash_func(void*);
+int  ht_default_cmp_func(void*, void*);
+void*  ht_default_copy_func(void*);
+void ht_default_free_func(void*);
+
+void ht_init(ht*);
+void ht_free(ht*);
+
+libds_result ht_put(ht*, void*, void*);
+void* ht_get(ht*, void*);
+void ht_remove(ht*, void*);
+
+int ht_foreach(ht*, void*, compare_func, foreach_func, ...);
+
+#endif