// EBML enum definitions and utils shared by the encoder and decoder

const tag_paths: uint = 0x01u;

const tag_items: uint = 0x02u;

const tag_paths_data: uint = 0x03u;

const tag_paths_data_name: uint = 0x04u;

const tag_paths_data_item: uint = 0x05u;

const tag_paths_data_mod: uint = 0x06u;

const tag_def_id: uint = 0x07u;

const tag_items_data: uint = 0x08u;

const tag_items_data_item: uint = 0x09u;

const tag_items_data_item_family: uint = 0x0au;

const tag_items_data_item_ty_param_bounds: uint = 0x0bu;

const tag_items_data_item_type: uint = 0x0cu;

const tag_items_data_item_symbol: uint = 0x0du;

const tag_items_data_item_variant: uint = 0x0eu;

const tag_items_data_parent_item: uint = 0x0fu;

const tag_index: uint = 0x11u;

const tag_index_buckets: uint = 0x12u;

const tag_index_buckets_bucket: uint = 0x13u;

const tag_index_buckets_bucket_elt: uint = 0x14u;

const tag_index_table: uint = 0x15u;

const tag_meta_item_name_value: uint = 0x18u;

const tag_meta_item_name: uint = 0x19u;

const tag_meta_item_value: uint = 0x20u;

const tag_attributes: uint = 0x21u;

const tag_attribute: uint = 0x22u;

const tag_meta_item_word: uint = 0x23u;

const tag_meta_item_list: uint = 0x24u;

// The list of crates that this crate depends on
const tag_crate_deps: uint = 0x25u;

// A single crate dependency
const tag_crate_dep: uint = 0x26u;

const tag_crate_hash: uint = 0x28u;

const tag_parent_item: uint = 0x29u;

const tag_crate_dep_name: uint = 0x2au;
const tag_crate_dep_hash: uint = 0x2bu;
const tag_crate_dep_vers: uint = 0x2cu;

const tag_mod_impl: uint = 0x30u;

const tag_item_iface_method: uint = 0x31u;
const tag_impl_iface: uint = 0x32u;

// discriminator value for variants
const tag_disr_val: uint = 0x34u;

// used to encode ast_map::path and ast_map::path_elt
const tag_path: uint = 0x40u;
const tag_path_len: uint = 0x41u;
const tag_path_elt_mod: uint = 0x42u;
const tag_path_elt_name: uint = 0x43u;
const tag_item_field: uint = 0x44u;
const tag_class_mut: uint = 0x45u;

const tag_region_param: uint = 0x46u;
const tag_mod_impl_iface: uint = 0x47u;
/*
  iface items contain tag_item_iface_method elements,
  impl items contain tag_item_impl_method elements, and classes
  have both. That's because some code treats classes like ifaces,
  and other code treats them like impls. Because classes can contain
  both, tag_item_iface_method and tag_item_impl_method have to be two
  different tags.
 */
const tag_item_impl_method: uint = 0x48u;
const tag_item_dtor: uint = 0x49u;

// used to encode crate_ctxt side tables
enum astencode_tag { // Reserves 0x50 -- 0x6f
    tag_ast = 0x50,

    tag_tree = 0x51,

    tag_id_range = 0x52,

    tag_table = 0x53,
    tag_table_id = 0x54,
    tag_table_val = 0x55,
    tag_table_def = 0x56,
    tag_table_node_type = 0x57,
    tag_table_node_type_subst = 0x58,
    tag_table_freevars = 0x59,
    tag_table_tcache,
    tag_table_param_bounds,
    tag_table_inferred_modes,
    tag_table_mutbl,
    tag_table_copy,
    tag_table_last_use,
    tag_table_spill,
    tag_table_method_map,
    tag_table_vtable_map,
    tag_table_borrowings
}

// djb's cdb hashes.
fn hash_node_id(&&node_id: int) -> uint { ret 177573u ^ (node_id as uint); }

fn hash_path(&&s: str) -> uint {
    let mut h = 5381u;
    for str::each(s) {|ch| h = (h << 5u) + h ^ (ch as uint); }
    ret h;
}