%% -*- erlang-indent-level: 2 -*-
%%
%% %CopyrightBegin%
%% 
%% Copyright Ericsson AB 2001-2009. All Rights Reserved.
%% 
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%% 
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%% 
%% %CopyrightEnd%
%%
%% ===========================================================================
%% Copyright (c) 2001 by Erik Johansson.  All Rights Reserved 
%% Time-stamp: <2008-04-20 14:54:00 richard>
%% ===========================================================================
%%  Module   :	hipe_temp_map
%%  Purpose  :  
%%  Notes    : 
%%  History  :	* 2001-07-24 Erik Johansson (happi@it.uu.se): Created.
%% ===========================================================================
%%  Exports  :
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

-module(hipe_temp_map).

-export([cols2tuple/2, is_spilled/2, to_substlist/1]).

-include("../main/hipe.hrl").

%%----------------------------------------------------------------------------
%% Convert a list of [{R0, C1}, {R1, C2}, ...] to a temp_map
%% (Currently implemented as a tuple) tuple {C1, C2, ...}.
%%
%% The indices (Ri) must be unique but do not have to be sorted and 
%% they can be sparse.
%% Note that the first allowed index is 0 -- this will be mapped to 
%% element 1
%%----------------------------------------------------------------------------

-spec cols2tuple(hipe_map(), atom()) -> hipe_temp_map().

cols2tuple(Map, Target) ->
  ?ASSERT(check_list(Map)),
  SortedMap = lists:keysort(1, Map), 
  cols2tuple(0, SortedMap, [], Target). 

%% sorted_cols2tuple(Map, Target) ->
%%   ?ASSERT(check_list(Map)),
%%   ?ASSERT(Map =:= lists:keysort(1, Map)),
%%   cols2tuple(0, Map, [], Target). 

%% Build a dense mapping 
cols2tuple(_, [], Vs, _) ->
  %% Done reverse the list and convert to tuple.
  list_to_tuple(lists:reverse(Vs));
cols2tuple(N, [{R, C}|Ms], Vs, Target) when N =:= R ->
  %% N makes sure the mapping is dense. N is he next key.
  cols2tuple(N+1, Ms, [C|Vs], Target);
cols2tuple(N, SourceMapping, Vs, Target) ->
  %% The source was sparse, make up some placeholders...
  Val = 	      
    case Target:is_precoloured(N) of
      %% If it is precoloured, we know what to map it to.
      true -> {reg, N};
      false -> unknown
    end,
  cols2tuple(N+1, SourceMapping, [Val|Vs], Target).

%%
%% True if temp Temp is spilled.
%%
-spec is_spilled(non_neg_integer(), hipe_temp_map()) -> boolean().

is_spilled(Temp, Map) ->
  case element(Temp+1, Map) of
    {reg, _R} -> false;
    {fp_reg, _R}-> false;
    {spill, _N} -> true;
    unknown -> false
  end.
    
%% %% True if temp Temp is allocated to a reg.
%% in_reg(Temp, Map) ->
%%   case element(Temp+1, Map) of
%%     {reg, _R} -> true;
%%     {fp_reg, _R}-> false;
%%     {spill, _N} -> false;
%%     unknown -> false
%%   end.
%%
%% %% True if temp Temp is allocated to a fp_reg.
%% in_fp_reg(Temp, Map) ->
%%   case element(Temp+1, Map) of
%%     {fp_reg, _R} -> true;
%%     {reg, _R} -> false;
%%     {spill, _N} -> false;
%%     unknown -> false
%%   end.
%% 
%% %% Returns the inf temp Temp is mapped to.
%% find(Temp, Map) -> element(Temp+1, Map).


%%
%% Converts a temp_map tuple back to a (sorted) key-list.
%%
-spec to_substlist(hipe_temp_map()) -> hipe_map().

to_substlist(Map) ->
  T = tuple_to_list(Map),
  mapping(T, 0).

mapping([R|Rs], Temp) ->
  [{Temp, R}| mapping(Rs, Temp+1)];
mapping([], _) ->
  [].