+struct btr_pool *btr_pool_new(size_t area_size);
+void btr_pool_free(struct btr_pool *btrp);
+size_t btr_pool_get_buffer(struct btr_pool *btrp, char **result);
+void btr_pool_allocate(struct btr_pool *btrp, size_t size);
+void btr_add_output_pool(struct btr_pool *btrp, char *buf, size_t size,
+ struct btr_node *btrn);
+