added initial lightweight heap allocator

evhtp_heap.h

@@ -1,5 +1,46 @@
 #ifndef __EVHTP_HEAP_H__
 #define __EVHTP_HEAP_H__
 
-#endif /* ____ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct evhtp_heap_s;
+
+typedef struct evhtp_heap_s evhtp_heap;
+
+/**
+ * @brief creates a new heap context
+ *
+ * @param size the size of the data to be allocated
+ * @param nelem the number of elements allocated with the size
+ *
+ * @return NULL on error
+ */
+EVHTP_EXPORT evhtp_heap * evhtp_heap_new(size_t size, size_t elts);
+
+/**
+ * @brief returns a single pre-allocated segment of memory from the heap list,
+ *        if there happens to be no entries left, one will be allocated, added to the
+ *        heap and returned.
+ *
+ * @param heap
+ *
+ * @return a block of data
+ */
+EVHTP_EXPORT void * evhtp_heap_alloc(evhtp_heap * heap);
+
+/**
+ * @brief removes the data entry, and places it back into a unused queue.
+ *
+ * @param heap
+ * @param d data that was returned from evhtp_heap_alloc()
+ */
+EVHTP_EXPORT void evhtp_heap_free(evhtp_heap * heap, void * data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif