-unsigned string_hash_func(const void *p);
-int string_compare_func(const void *a, const void *b);
-
-unsigned trivial_hash_func(const void *p);
-int trivial_compare_func(const void *a, const void *b);
-
-unsigned uint64_hash_func(const void *p);
-int uint64_compare_func(const void *a, const void *b);
-
-Hashmap *hashmap_new(hash_func_t hash_func, compare_func_t compare_func);
+struct hash_ops {
+ hash_func_t hash;
+ compare_func_t compare;
+};
+
+unsigned long string_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
+int string_compare_func(const void *a, const void *b) _pure_;
+extern const struct hash_ops string_hash_ops;
+
+/* This will compare the passed pointers directly, and will not
+ * dereference them. This is hence not useful for strings or
+ * suchlike. */
+unsigned long trivial_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
+int trivial_compare_func(const void *a, const void *b) _const_;
+extern const struct hash_ops trivial_hash_ops;
+
+/* 32bit values we can always just embedd in the pointer itself, but
+ * in order to support 32bit archs we need store 64bit values
+ * indirectly, since they don't fit in a pointer. */
+unsigned long uint64_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
+int uint64_compare_func(const void *a, const void *b) _pure_;
+extern const struct hash_ops uint64_hash_ops;
+
+/* On some archs dev_t is 32bit, and on others 64bit. And sometimes
+ * it's 64bit on 32bit archs, and sometimes 32bit on 64bit archs. Yuck! */
+#if SIZEOF_DEV_T != 8
+unsigned long devt_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
+int devt_compare_func(const void *a, const void *b) _pure_;
+extern const struct hash_ops devt_hash_ops = {
+ .hash = devt_hash_func,
+ .compare = devt_compare_func
+};
+#else
+#define devt_hash_func uint64_hash_func
+#define devt_compare_func uint64_compare_func
+#define devt_hash_ops uint64_hash_ops
+#endif
+
+Hashmap *hashmap_new(const struct hash_ops *hash_ops);