object: hashmap: implement integer-based hashmap keys

rather than always interpreting a b_hashmap_key as a buffer to be hashed,
b_hashmap can now be told to consider the value of the key_data pointer itself
as the key, treating it as a buffer of size sizeof(void*).

object/include/blue/object/hashmap.h

@@ -7,6 +7,7 @@
 #include <blue/core/status.h>
 #include <blue/object/object.h>
 #include <blue/object/type.h>
+#include <stddef.h>
 
 #define B_HASHMAP(p) ((b_hashmap *)(p))
 
@@ -38,7 +39,12 @@ typedef struct b_hashmap b_hashmap;
 typedef void (*b_hashmap_key_destructor)(void *);
 typedef void (*b_hashmap_value_destructor)(void *);
 
+typedef enum b_hashmap_key_flags {
+	B_HASHMAP_KEY_F_INTVALUE = 0x01u,
+} b_hashmap_key_flags;
+
 typedef struct b_hashmap_key {
+	b_hashmap_key_flags key_flags;
 	const void *key_data;
 	size_t key_size;
 } b_hashmap_key;