+char *base64encode(char *data, size_t datalen);
+char *base64decode(char *data, size_t *datalen);
+int bbtreedel(struct btree **tree, void *item, int (*cmp)(void *, void *));
+void freebtree(struct btree **tree, void (*ffunc)(void *));
+int bbtreeput(struct btree **tree, void *item, int (*cmp)(void *, void *));
+void *btreeget(struct btree *tree, void *key, int (*cmp)(void *, void *));