lots of work towards flattening the records. stalled at ezic_rule:next_event/4

2010-11-07 18:32:37 -08:00
parent c795abf2b6
commit 9ad8f3c826
12 changed files with 479 additions and 115 deletions
--- a/include/ezic.hrl
+++ b/include/ezic.hrl
@@ -17,7 +17,7 @@


 % a flattened zone record, giving specific information for a specific time range.
-record(flatzone, {tzname, tzrule, from, to, gmtoff}).
+-record(flatzone, {tzname, wall_from, wall_to, std_from, std_to, utc_from, utc_to, offset}).



--- a/notes/flattening.svg
+++ b/notes/flattening.svg
@@ -0,0 +1,122 @@
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--- a/src/ezic.erl
+++ b/src/ezic.erl
@@ -49,7 +49,8 @@ utc_to_local(UTCDatetime, TzName) ->
 next_timechange(TzName) ->
    next_timechange(erlang:universaltime(), TzName).

-next_timechange(UtcDatetime, TzName) ->
+next_timechange(UTCDatetime, TzName) ->
+    UTCDatetime, TzName,
    not_done.


@@ -63,7 +64,8 @@ next_timechange(UtcDatetime, TzName) ->


 load(Folder) ->
-    ezic_loader:load(Folder).
+    ezic_loader:load(Folder),
+    ezic_flatten:flatten().


 dev_start() ->
@@ -106,6 +108,6 @@ time_offset(Zone, Rule) ->
 date_add(Datetime, SecDiff) ->
    ?gs2dt(?dt2gs(Datetime) + SecDiff).    

-date_subtract(Datetime, SecDiff) ->
-    ?gs2dt(?dt2gs(Datetime) - SecDiff).
+%% date_subtract(Datetime, SecDiff) ->
+%%     ?gs2dt(?dt2gs(Datetime) - SecDiff).
    
--- a/src/ezic_date.erl
+++ b/src/ezic_date.erl
@@ -8,10 +8,14 @@
 -endif.


+
+
 -export([for/2]).
 -export([month_to_num/1, day_to_num/1]).
 -export([compare_times/2, compare_datetimes/2, normalize/1, overlap/2, date_between/2]).

+-export([add_seconds/2, all_times/3]).
+



@@ -218,3 +222,52 @@ date_between_normal(D1, {D2s, D2e}) ->
 	andalso compare_datetimes_normal(D1, D2e).
    
    
+
+
+add_seconds(Datetime, Seconds) ->
+    calendar:gregorian_seconds_to_datetime(
+      calendar:date_to_gregorian_seconds(Datetime) + Seconds
+     ).
+
+
+
+
+
+% returns {WallTime, StdTime, UtcTime} 
+% where each is a datetime tuple: {{Y,M,D}{HH,MM,SS}}
+
+% universal time given
+all_times(Datetime=#tztime{time=UTCTime, flag=Flag}, Offset, DSTOffset) 
+  when Flag=:=u; Flag=:=g; Flag=:=z ->
+    OSec= calendar:time_to_seconds(Offset),
+    DSTSec= calendar:time_to_seconds(DSTOffset),
+
+    STDTime= add_seconds(UTCTime, OSec),
+    WallTime= add_seconds(STDTime, DSTSec),
+
+    {WallTime, STDTime, UTCTime};
+
+
+% standard time given
+all_times(Datetime=#tztime{time=STDTime, flag=s}, Offset, DSTOffset) ->
+    OSec= calendar:time_to_seconds(Offset),
+    DSTSec= calendar:time_to_seconds(DSTOffset),
+
+    UTCTime= add_seconds(STDTime, -1*OSec),
+    WallTime= add_seconds(STDTime, DSTSec),
+
+    {WallTime, STDTime, UTCTime};
+
+
+% wall time given
+all_times(Datetime=#tztime{time=WallTime, flag=Flag}, Offset, DSTOffset) 
+  when Flag=:=w, Flag=:=undefined ->
+    OSec= calendar:time_to_seconds(Offset),
+    DSTSec= calendar:time_to_seconds(DSTOffset),
+
+    STDTime= add_seconds(WallTime, -1*DSTSec),
+    UTCTime= add_seconds(STDTime, -1*OSec),
+
+    {WallTime, STDTime, UTCTime}.
+
+
--- a/src/ezic_db.erl
+++ b/src/ezic_db.erl
@@ -1,13 +1,28 @@
-
 -module(ezic_db).
 -include("include/ezic.hrl").
 -include_lib("stdlib/include/qlc.hrl").


 -export([zones/1, rules/1]).
-export([wipe/0, init/0, insert_all/1, getall/1]).
+-export([wipe/0, init/0, insert_all/1, get_all/1]).


+-define(create(Record),
+	{atomic, ok} = mnesia:create_table(Record, 
+			   [{type, bag}
+			    , {disc_copies, [node()]}
+			    , {attributes, record_info(fields, Record)}
+			   ])).
+
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% READ - db reading methods
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+
+% retrieve all zones by name
 zones(Name) ->
    F = fun()->
 		Q = qlc:q([Z || Z=#zone{name=N} <- mnesia:table(zone), N=:=Name]),
@@ -16,6 +31,7 @@ zones(Name) ->
    {atomic, Zones}= mnesia:transaction(F),
    Zones.
    
+% retrieve all rules by name
 rules(Name) ->
    F = fun()->
 		Q = qlc:q([R || R=#rule{name=N} <- mnesia:table(rule), N=:=Name]),
@@ -24,46 +40,22 @@ rules(Name) ->
    {atomic, Rules}= mnesia:transaction(F),
    Rules.
    
+% get all records from table
+get_all(Tab) when is_atom(Tab) ->
+    F = fun() ->
+		Q = qlc:q([R || R<- mnesia:table(Tab)]),
+		qlc:e(Q)
+	end,
+    {atomic, Ret}= mnesia:transaction(F),
+    Ret.
    

+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% WRITE - insertion/edit methods
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



-
-define(create(Record),
-	{atomic, ok} = mnesia:create_table(Record, [{type, bag}, {disc_copies, [node()]},{attributes, record_info(fields, Record)}])).
-
-
-init() ->
-    create_tabs(mnesia:create_schema([node()])),
-    mnesia:wait_for_tables([rule, zone, link, leap], 3000).
-
-wipe() ->
-    mnesia:stop(),
-    mnesia:delete_schema([node()]).
-
-
-create_tabs(ok) ->
-    mnesia:start(),
-
-    ?create(rule),
-    ?create(zone),
-    ?create(link),
-    ?create(leap),
-
-    %% {atomic, ok}= mnesia:create_table(rule, [{disc_copies, [node()]},{attributes, record_info(fields, rule)}]),
-    %% {atomic, ok}= mnesia:create_table(zone, [{disc_copies, [node()]},{attributes, record_info(fields, zone)}]),
-    %% {atomic, ok}= mnesia:create_table(leap, [{disc_copies, [node()]},{attributes, record_info(fields, leap)}]),
-    %% {atomic, ok}= mnesia:create_table(link, [{disc_copies, [node()]},{attributes, record_info(fields, link)}]);
-
-    ok;
-create_tabs({error, {_, {already_exists,_}}}) ->
-    mnesia:start(),
-    ok;
-create_tabs(E) ->
-    ?debug(E).
-
-
 insert_all(Records) ->
    mnesia:transaction(
      fun() ->
@@ -74,10 +66,40 @@ insert_all(Records) ->
 			       


-getall(Tab) when is_atom(Tab) ->
-    F = fun() ->
-		Q = qlc:q([R || R<- mnesia:table(Tab)]),
-		qlc:e(Q)
-	end,
-    mnesia:transaction(F).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% ADMIN - initialization and administration methods
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+% initialize the db
+init() ->
+    create_tabs(mnesia:create_schema([node()])),
+    mnesia:wait_for_tables([rule, zone, link, leap], 3000).
+
+
+% WARNING: deletes all db files
+wipe() ->
+    mnesia:stop(),
+    mnesia:delete_schema([node()]).
+
+
+create_tabs(ok) ->
+    mnesia:start(),
+
+    ?create(rule),
+    ?create(zone),
+    ?create(link),
+    ?create(leap),
+    ?create(flatzone),
+
+    ok;
+create_tabs({error, {_, {already_exists,_}}}) ->
+    mnesia:start(),
+    ok;
+create_tabs(E) ->
+    ?debug(E).
+
+
+

--- a/src/ezic_flatten.erl
+++ b/src/ezic_flatten.erl
@@ -0,0 +1,145 @@
+-module(ezic_flatten).
+-include("include/ezic.hrl").
+
+-define(FLAT(W,S,U), #flatzone{wall_from=W, std_from=S, utc_from=U}).
+-define(ENDFLAT(F,W,S,U), F#flatzone{wall_to=W, std_to=S, utc_to=U}).
+-define(MINFLAT, ?FLAT(minimum,minimum,minimum)).
+
+
+
+
+-export([flatten/0]).
+
+
+
+
+flatten() ->
+    AllZones= ezic_db:get_all(zone),
+    flatten_zones(AllZones),
+    not_done.
+
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% PRIVATE
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+
+make_next_flat(#flatzone{wall_to=W, std_to=S, utc_to=U, offset=O}) ->
+    make_next_flat({W,S,U}, O);
+make_next_flat(EndTimes) ->
+    make_next_flat(EndTimes, undefined).
+
+
+make_next_flat({W,S,U}, O) ->
+    FW= ezic_date:add_seconds(W,1),
+    FS= ezic_date:add_seconds(S,1),
+    FU= ezic_date:add_seconds(U,1),
+    Flat= ?FLAT(FW, FS, FU),
+    Flat#flatzone{offset=O}.
+
+    
+    
+end_flat(Flat=#flatzone{}, {W,S,U}) ->
+    ?ENDFLAT(Flat,W,S,U).
+
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% INTERNAL
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+
+
+% recursively processes sets of similar zones until they're all done, passing zone sets to flatten_zone_set/1
+flatten_zones(Zones) ->
+    flatten_zones(Zones, []).
+
+flatten_zones([], Flats) ->
+    Flats;
+flatten_zones([Z1|_]= AllZones, Flats) ->
+    {CurrentZones, RestZones}= ezic_zone:split_by_name(Z1, AllZones),
+
+    SortedZones= lists:sort(fun ezic_zone:sort_ascending/2, CurrentZones),
+    NewFlats= lists:merge(Flats, flatten_zone_set(SortedZones)),
+
+    flatten_zones(RestZones, NewFlats).
+
+
+
+
+
+
+
+
+
+
+
+
+% takes zones one-by-one, gathering relevant rules and create flat periods of the same gmt offset (#flatzone)
+flatten_zone_set(Zones) ->
+    flatten_zone_set(?MINFLAT, Zones, []).
+
+
+% flatten_zone_set(FromTime, Zones, Flats) -> [#flatzone{}]
+%    FromTime= #flatzone{*_from =/= undefined}
+%    Zones= [#zone{}]
+%    Flats= [#flatzone{}]
+%
+% assumes a new zone every time it is called
+flatten_zone_set(_, [], Flats) ->
+    Flats;
+flatten_zone_set(FromTimeStub, [Z1=#zone{rule=RuleName, until=UntilTime, gmtoff=Offset} | RestZones] = Zones, Flats) ->
+
+    %% we have a flatzone with start times, we populate the base offset
+    FromTime= FromTimeStub#flatzone{offset=Offset},
+    
+    
+
+    %% we gather all rules that _may_ apply (same year)
+    Rules= ezic_db:rules(RuleName),
+    RelevantRules= ezic_rule:filter(FromTime, UntilTime, Rules),
+    SortedRules= lists:sort(fun ezic_rule:sort_ascending/2, RelevantRules),
+
+    %% Then we plot points, bouncing from rule to rule, ending when the zone ends
+    {ok, NextFromTimeStub, NewFlats}= flatten_zone(FromTime, Z1, SortedRules),
+    
+    
+    not_done.
+
+
+
+
+
+
+
+
+
+
+% flattens a single zone into multiple flatzones.
+% FromTime has its *_from fields and offset field populated. (it should anyway)
+% @todo invalid input checking
+% Rules are sorted
+flatten_zone(BaseFlat, Zone, Rules) ->
+    flatten_zone(BaseFlat, Zone, Rules, []).
+    
+flatten_zone(BaseFlat, Zone=#zone{until=Until, gmtoff=Offset}, Rules, Flats) ->
+    case ezic_rule:next_event(BaseFlat, Until, Offset, Rules) of
+         % is this enough information to compare all times corectly?
+	{end_until, EndTimes} ->
+	    NewFlats= [end_flat(BaseFlat, EndTimes) | Flats],
+	    NewFrom= make_next_flat(EndTimes),
+	    {ok, NewFrom, NewFlats}; % base case
+	
+	{end_rule, EndTimes, NextOffset} ->
+	    NewFlats= [end_flat(BaseFlat, EndTimes) | Flats],
+	    NewFrom= make_next_flat(EndTimes, NextOffset),
+	    flatten_zone(NewFrom, Zone, Rules, NewFlats) % tail recursion
+
+	end.
+
+
+
+
--- a/src/ezic_loader.erl
+++ b/src/ezic_loader.erl
@@ -15,8 +15,6 @@ load(File) ->
 	end,
    {ok, Zones, Rules, Leaps, Links} = ezic_compile:separate(Records),

-%    ezic_compile:flatten(Zones, Rules).
-
    ezic_db:wipe(),
    ezic_db:init(),

@@ -30,6 +28,7 @@ load(File) ->



+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % INTERNAL
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -38,7 +37,6 @@ load(File) ->

 % returns a list of tzdata records for all files in folder
 % note: assumes every file in the folder is a tzdata file
-% this method does not recurse.
 parse_dir(Folder) ->
    {ok, Files} = file:list_dir(Folder),
    lists:flatten([ parse_file(filename:join(Folder,File)) || File <- Files ]).
@@ -52,24 +50,33 @@ parse_file(File) ->



+
 parse_lines(eof, _, Records) ->
    Records;
 parse_lines({ok, Line}, File, Records) ->
    StrLine= clean_line(Line),
-    case length(StrLine) > 0 of
-	false -> parse_lines(file:read_line(File), File, Records);
-	true -> parse_lines_2(StrLine, File, Records)
-    end.
+    NewRecords= case length(StrLine) > 0 of
+	false -> Records;
+	true -> [parse_to_record(StrLine, File, Records) | Records]
+    end,
+    parse_lines(file:read_line(File), File, NewRecords).


-parse_lines_2(Line, File, Records) ->
-    %?debug("Line: ~p", [Line]),
+
+% the Line has data, so we parse it, build a record, and return it
+parse_to_record(Line, File, Records) ->
    [Type | Data] = string:tokens(Line, " \t"),
    {ok, PrevType, PrevName} = prev_rec_type(Records),
    {ok, Record} = build_record(Type, Data, {PrevType, PrevName}),
-    parse_lines(file:read_line(File), File, [Record|Records]).
+
+%    parse_lines(file:read_line(File), File, [Record|Records]).
+
+    Record.


+
+
+% retrieves the previous record type, in case Zone continuations occur (multiline)
 prev_rec_type([]) ->
    {ok, null, null};
 prev_rec_type([#zone{name=Name}|_]) ->
@@ -77,6 +84,9 @@ prev_rec_type([#zone{name=Name}|_]) ->
 prev_rec_type(List) when is_list(List) ->
    {ok, void, void}.

+
+
+
 clean_line(Line) ->
    Line1= string:strip(Line),
    Line2= string:strip(Line1, both, $\n),
@@ -105,3 +115,6 @@ build_record("Leap", Data,_) ->
 build_record(Type, Data, PT) ->
    {error, {badLine, Type, Data, PT}}.

+
+
+
--- a/src/ezic_record.erl
+++ b/src/ezic_record.erl
@@ -136,6 +136,7 @@ parse_save(X) ->
    parse_save_rev(XRev).


+
 parse_time("-") ->
    #tztime{time={0,0,0}};
 parse_time(TS) ->
--- a/src/ezic_rule.erl
+++ b/src/ezic_rule.erl
@@ -2,62 +2,39 @@
 -include("include/ezic.hrl").


-export([current/2, current_set/2, sort/2]).
-export([from_time/1, dst_sec/1]).
-
-
-
-current(_, []) ->
-    none;
-current(Now, Rules) ->
-    Current_SetRules= lists:filter(fun(R)-> current_set(Now, R) end, Rules),
-%    ?debug("Current_SetRules: ~p", [Current_SetRules]),
-    SRules= lists:sort(fun sort/2, Current_SetRules),
-    CRule= choose_rule(SRules),
-    CRule.
+-export([next_event/4]).




-% newest first
-sort(R1, R2) ->
-    T1= from_time(R1),
-    T2= from_time(R2),
-    ezic_date:compare_datetimes(T2, T1).
+% determines the next zone or dst change event
+% returns the latest possible times the previous period is in effect (`Until -1sec` in most cases)
+% Rules are sorted
+next_event(BaseFlat, ZoneEnd, Offset, []) ->
+    {end_until, make_times(ZoneEnd, Offset)};

+% BaseFlat has offset defined
+% @todo ensure offset defined on BaseFlat
+% Rules are sorted in ascending order (oldest first)
+next_event(BaseFlat=#flatzone{utc_from=#tztime{time={{Year,_,_},_}}}, 
+	   ZoneEnd, ZoneOffset, [Rule|RestRules]) ->

-
-current_set(Now, Rule=#rule{from=F, to=T}) ->
-    {{Y,_,_},_} = Now,
-    case ezic_date:date_between(Y, {F,T}) of
-	false -> false;
-	true -> current_set2(Now, Rule)
-    end.
-
-
-current_set2(Now, #rule{in=Month, on=Day, at=Time}) ->
-    {{Y,_,_},_} = Now,
-    RTime= {{Y, Month, Day}, Time},
-    ezic_date:compare_datetimes(RTime, Now).
-
-
-
-from_time(#rule{from=F, in=M, on=O, at=A}) ->
-    {{F,M,O},A}.
+    not_done.





-choose_rule([]) ->
-    none;
-choose_rule([H|_]) ->
-    H.
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% PRIVATE
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% create endtimes for a #flatzone, with no dst offset
+make_times(Until, Offset) ->
+    make_times(Until, Offset, 0).
+
+make_times(Until, Offset, DSTOffset) ->
+    ezic_date:all_times(Until, Offset, DSTOffset).


-dst_sec(none) ->
-    0;
-dst_sec(Rule) ->
-    calendar:time_to_seconds((Rule#rule.save)#tztime.time).
-

--- a/src/ezic_zone.erl
+++ b/src/ezic_zone.erl
@@ -1,11 +1,13 @@
 -module(ezic_zone).
 -include("include/ezic.hrl").
+-include_lib("eunit/include/eunit.hrl").

 -export([
 	 current/1
 	 , current_as_of_utc/2
-	 , sort/2
-	 , revsort/2
+	 , split_by_name/2
+	 , sort_ascending/2
+	 , sort_descending/2
 	 , offset_sec/1
 	]).

@@ -28,8 +30,8 @@ current_as_of_utc(UTCDatetime, TzName) ->

 get_zone_utc(_, []) ->
    erlang:error(no_current);
-get_zone_utc(UTCDatetime, Zones) ->
-    SortedZones= lists:sort(fun revsort/2, Zones),
+get_zone_utc(_UTCDatetime, Zones) ->
+    _SortedZones= lists:sort(fun sort_descending/2, Zones),
 %%    [CZone|_]= lists:dropwhile(fun(SZ)-> older_zone_utc(SZ, UTCDatetime) end, SortedZones),
 %%    CZone.

@@ -43,17 +45,29 @@ get_zone_utc(UTCDatetime, Zones) ->
 			       


-sort(#zone{until=U1}, #zone{until=U2}) ->
+
+% returns {[SimilarZone], [DifferentZone]} 
+%   where Similar Zones are those with the same name as Zone
+%   and DifferentZones are all the rest
+split_by_name(#zone{name=N}, Zones) ->
+    lists:partition(
+      fun(#zone{name=NI}) ->
+	      N =:= NI
+      end
+      , Zones).
+
+
+sort_descending(#zone{until=U1}, #zone{until=U2}) ->
    ezic_date:compare_datetimes(U2, U1).

-revsort(Z1=#zone{}, Z2=#zone{}) ->
-    not sort(Z1, Z2).
+sort_ascending(Z1=#zone{}, Z2=#zone{}) ->
+    not sort_descending(Z1, Z2).



 % @bug doesn't normalize times. Times are self-relative (to standard time), and Now may come from any timezone unless we're careful about that.
-older_zone(#zone{until=Until}, UTCDatetime) ->
-    ezic_date:compare_datetimes(Until, UTCDatetime).
+%% older_zone(#zone{until=Until}, UTCDatetime) ->
+%%     ezic_date:compare_datetimes(Until, UTCDatetime).



--- a/test/ezic_zone_tests.erl
+++ b/test/ezic_zone_tests.erl
@@ -0,0 +1,14 @@
+-module(ezic_zone_tests).
+-include("include/ezic.hrl").
+-include_lib("eunit/include/eunit.hrl").
+
+split_by_name_test_() ->
+    AZones= [A=#zone{name=a}, #zone{name=a}, #zone{name=a}],
+    BZones= [B=#zone{name=b}, #zone{name=b}, #zone{name=b}],
+    AllZones= lists:merge(AZones, BZones),
+
+    [
+     ?_assertEqual({AZones, BZones}, ezic_zone:split_by_name(A, AllZones))
+     , ?_assertEqual({BZones, AZones}, ezic_zone:split_by_name(B, AllZones))
+     , ?_assertEqual({[], AllZones}, ezic_zone:split_by_name(#zone{name=c}, AllZones))
+    ].
--- a/test/test.erl
+++ b/test/test.erl
@@ -4,4 +4,5 @@

 all() ->
    eunit:test(ezic_record),
-    eunit:test(ezic_date).
+    eunit:test(ezic_date),
+    eunit:test(ezic_zone).