Added date and password entry; still needs lots of work.

arena_allocator.h

@@ -0,0 +1,25 @@
+#ifndef ARENA_ALLOCATOR_SENTRY
+#define ARENA_ALLOCATOR_SENTRY
+
+#ifndef ARENA_ALIGNMENT
+#define ARENA_ALIGNMENT 2*sizeof(void *)
+#endif
+
+#define ARENA_ALLOC(a, t) (t *)arena_alloc(a, sizeof(t))
+#define ARENA_DEALLOC(a, t) arena_dealloc(a, sizeof(t))
+
+struct arena {
+    unsigned long long size;
+    unsigned long long used;
+    void *memory;
+};
+
+struct arena arena_init(void *backing_store, unsigned long long size);
+void arena_reset(struct arena *arena);
+void arena_tidy(struct arena *arena);
+void *arena_alloc(struct arena *arena, unsigned long long size);
+void arena_dealloc(struct arena *arena, unsigned long long size);
+struct arena temp_arena_begin(struct arena *arena);
+void temp_arena_end(struct arena *arena);
+
+#endif