%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2010. 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%
%%
-module(lists).
-compile({no_auto_import,[max/2]}).
-compile({no_auto_import,[min/2]}).
-export([append/2, append/1, subtract/2, reverse/1,
nth/2, nthtail/2, prefix/2, suffix/2, last/1,
seq/2, seq/3, sum/1, duplicate/2, min/1, max/1, sublist/2, sublist/3,
delete/2,
unzip/1, unzip3/1, zip/2, zip3/3, zipwith/3, zipwith3/4,
sort/1, merge/1, merge/2, rmerge/2, merge3/3, rmerge3/3,
usort/1, umerge/1, umerge3/3, umerge/2, rumerge3/3, rumerge/2,
concat/1, flatten/1, flatten/2, flatlength/1,
keydelete/3, keyreplace/4, keytake/3, keystore/4,
keysort/2, keymerge/3, rkeymerge/3, rukeymerge/3,
ukeysort/2, ukeymerge/3, keymap/3]).
%% Bifs: member/2, reverse/2
%% Bifs: keymember/3, keysearch/3, keyfind/3
-export([merge/3, rmerge/3, sort/2, umerge/3, rumerge/3, usort/2]).
-export([all/2,any/2,map/2,flatmap/2,foldl/3,foldr/3,filter/2,
partition/2,zf/2,
mapfoldl/3,mapfoldr/3,foreach/2,takewhile/2,dropwhile/2,splitwith/2,
split/2]).
%% member(X, L) -> (true | false)
%% test if X is a member of the list L
%% Now a BIF!
%member(X, [X|_]) -> true;
%member(X, [_|Y]) ->
% member(X, Y);
%member(X, []) -> false.
%% append(X, Y) appends lists X and Y
-spec append([T], [T]) -> [T].
append(L1, L2) -> L1 ++ L2.
%% append(L) appends the list of lists L
-spec append([[T]]) -> [T].
append([E]) -> E;
append([H|T]) -> H ++ append(T);
append([]) -> [].
%% subtract(List1, List2) subtract elements in List2 form List1.
-spec subtract([T], [T]) -> [T].
subtract(L1, L2) -> L1 -- L2.
%% reverse(L) reverse all elements in the list L. Is now a BIF!
-spec reverse([T]) -> [T].
reverse([] = L) ->
L;
reverse([_] = L) ->
L;
reverse([A, B]) ->
[B, A];
reverse([A, B | L]) ->
lists:reverse(L, [B, A]).
%reverse([H|T], Y) ->
% reverse(T, [H|Y]);
%reverse([], X) -> X.
%% nth(N, L) returns the N`th element of the list L
%% nthtail(N, L) returns the N`th tail of the list L
-spec nth(pos_integer(), [T,...]) -> T.
nth(1, [H|_]) -> H;
nth(N, [_|T]) when N > 1 ->
nth(N - 1, T).
-spec nthtail(non_neg_integer(), [T,...]) -> [T].
nthtail(1, [_|T]) -> T;
nthtail(N, [_|T]) when N > 1 ->
nthtail(N - 1, T);
nthtail(0, L) when is_list(L) -> L.
%% prefix(Prefix, List) -> (true | false)
-spec prefix([T], [T]) -> boolean().
prefix([X|PreTail], [X|Tail]) ->
prefix(PreTail, Tail);
prefix([], List) when is_list(List) -> true;
prefix([_|_], List) when is_list(List) -> false.
%% suffix(Suffix, List) -> (true | false)
-spec suffix([T], [T]) -> boolean().
suffix(Suffix, List) ->
Delta = length(List) - length(Suffix),
Delta >= 0 andalso nthtail(Delta, List) =:= Suffix.
%% last(List) returns the last element in a list.
-spec last([T,...]) -> T.
last([E|Es]) -> last(E, Es).
last(_, [E|Es]) -> last(E, Es);
last(E, []) -> E.
%% seq(Min, Max) -> [Min,Min+1, ..., Max]
%% seq(Min, Max, Incr) -> [Min,Min+Incr, ..., Max]
%% returns the sequence Min..Max
%% Min <= Max and Min and Max must be integers
-spec seq(integer(), integer()) -> [integer()].
seq(First, Last)
when is_integer(First), is_integer(Last), First-1 =< Last ->
seq_loop(Last-First+1, Last, []).
seq_loop(N, X, L) when N >= 4 ->
seq_loop(N-4, X-4, [X-3,X-2,X-1,X|L]);
seq_loop(N, X, L) when N >= 2 ->
seq_loop(N-2, X-2, [X-1,X|L]);
seq_loop(1, X, L) ->
[X|L];
seq_loop(0, _, L) ->
L.
-spec seq(integer(), integer(), integer()) -> [integer()].
seq(First, Last, Inc)
when is_integer(First), is_integer(Last), is_integer(Inc) ->
if
Inc > 0, First - Inc =< Last;
Inc < 0, First - Inc >= Last ->
N = (Last - First + Inc) div Inc,
seq_loop(N, Inc*(N-1)+First, Inc, []);
Inc =:= 0, First =:= Last ->
seq_loop(1, First, Inc, [])
end.
seq_loop(N, X, D, L) when N >= 4 ->
Y = X-D, Z = Y-D, W = Z-D,
seq_loop(N-4, W-D, D, [W,Z,Y,X|L]);
seq_loop(N, X, D, L) when N >= 2 ->
Y = X-D,
seq_loop(N-2, Y-D, D, [Y,X|L]);
seq_loop(1, X, _, L) ->
[X|L];
seq_loop(0, _, _, L) ->
L.
%% sum(L) returns the sum of the elements in L
-spec sum([number()]) -> number().
sum(L) -> sum(L, 0).
sum([H|T], Sum) -> sum(T, Sum + H);
sum([], Sum) -> Sum.
%% duplicate(N, X) -> [X,X,X,.....,X] (N times)
%% return N copies of X
-spec duplicate(non_neg_integer(), T) -> [T].
duplicate(N, X) when is_integer(N), N >= 0 -> duplicate(N, X, []).
duplicate(0, _, L) -> L;
duplicate(N, X, L) -> duplicate(N-1, X, [X|L]).
%% min(L) -> returns the minimum element of the list L
-spec min([T,...]) -> T.
min([H|T]) -> min(T, H).
min([H|T], Min) when H < Min -> min(T, H);
min([_|T], Min) -> min(T, Min);
min([], Min) -> Min.
%% max(L) -> returns the maximum element of the list L
-spec max([T,...]) -> T.
max([H|T]) -> max(T, H).
max([H|T], Max) when H > Max -> max(T, H);
max([_|T], Max) -> max(T, Max);
max([], Max) -> Max.
%% sublist(List, Start, Length)
%% Returns the sub-list starting at Start of length Length.
-spec sublist([T], pos_integer(), non_neg_integer()) -> [T].
sublist(List, S, L) when is_integer(L), L >= 0 ->
sublist(nthtail(S-1, List), L).
-spec sublist([T], non_neg_integer()) -> [T].
sublist(List, L) when is_integer(L), is_list(List) ->
sublist_2(List, L).
sublist_2([H|T], L) when L > 0 ->
[H|sublist_2(T, L-1)];
sublist_2(_, 0) ->
[];
sublist_2(List, L) when is_list(List), L > 0 ->
[].
%% delete(Item, List) -> List'
%% Delete the first occurrence of Item from the list L.
-spec delete(T, [T]) -> [T].
delete(Item, [Item|Rest]) -> Rest;
delete(Item, [H|Rest]) ->
[H|delete(Item, Rest)];
delete(_, []) -> [].
%% Return [{X0, Y0}, {X1, Y1}, ..., {Xn, Yn}] for lists [X0, X1, ...,
%% Xn] and [Y0, Y1, ..., Yn].
-spec zip([A], [B]) -> [{A, B}].
zip([X | Xs], [Y | Ys]) -> [{X, Y} | zip(Xs, Ys)];
zip([], []) -> [].
%% Return {[X0, X1, ..., Xn], [Y0, Y1, ..., Yn]}, for a list [{X0, Y0},
%% {X1, Y1}, ..., {Xn, Yn}].
-spec unzip([{A, B}]) -> {[A], [B]}.
unzip(Ts) -> unzip(Ts, [], []).
unzip([{X, Y} | Ts], Xs, Ys) -> unzip(Ts, [X | Xs], [Y | Ys]);
unzip([], Xs, Ys) -> {reverse(Xs), reverse(Ys)}.
%% Return [{X0, Y0, Z0}, {X1, Y1, Z1}, ..., {Xn, Yn, Zn}] for lists [X0,
%% X1, ..., Xn], [Y0, Y1, ..., Yn] and [Z0, Z1, ..., Zn].
-spec zip3([A], [B], [C]) -> [{A, B, C}].
zip3([X | Xs], [Y | Ys], [Z | Zs]) -> [{X, Y, Z} | zip3(Xs, Ys, Zs)];
zip3([], [], []) -> [].
%% Return {[X0, X1, ..., Xn], [Y0, Y1, ..., Yn], [Z0, Z1, ..., Zn]}, for
%% a list [{X0, Y0, Z0}, {X1, Y1, Z1}, ..., {Xn, Yn, Zn}].
-spec unzip3([{A, B, C}]) -> {[A], [B], [C]}.
unzip3(Ts) -> unzip3(Ts, [], [], []).
unzip3([{X, Y, Z} | Ts], Xs, Ys, Zs) ->
unzip3(Ts, [X | Xs], [Y | Ys], [Z | Zs]);
unzip3([], Xs, Ys, Zs) ->
{reverse(Xs), reverse(Ys), reverse(Zs)}.
%% Return [F(X0, Y0), F(X1, Y1), ..., F(Xn, Yn)] for lists [X0, X1, ...,
%% Xn] and [Y0, Y1, ..., Yn].
-spec zipwith(fun((X, Y) -> R), [X], [Y]) -> [R].
zipwith(F, [X | Xs], [Y | Ys]) -> [F(X, Y) | zipwith(F, Xs, Ys)];
zipwith(F, [], []) when is_function(F, 2) -> [].
%% Return [F(X0, Y0, Z0), F(X1, Y1, Z1), ..., F(Xn, Yn, Zn)] for lists
%% [X0, X1, ..., Xn], [Y0, Y1, ..., Yn] and [Z0, Z1, ..., Zn].
-spec zipwith3(fun((X, Y, Z) -> R), [X], [Y], [Z]) -> [R].
zipwith3(F, [X | Xs], [Y | Ys], [Z | Zs]) ->
[F(X, Y, Z) | zipwith3(F, Xs, Ys, Zs)];
zipwith3(F, [], [], []) when is_function(F, 3) -> [].
%% sort(List) -> L
%% sorts the list L
-spec sort([T]) -> [T].
sort([X, Y | L] = L0) when X =< Y ->
case L of
[] ->
L0;
[Z] when Y =< Z ->
L0;
[Z] when X =< Z ->
[X, Z, Y];
[Z] ->
[Z, X, Y];
_ when X == Y ->
sort_1(Y, L, [X]);
_ ->
split_1(X, Y, L, [], [])
end;
sort([X, Y | L]) ->
case L of
[] ->
[Y, X];
[Z] when X =< Z ->
[Y, X | L];
[Z] when Y =< Z ->
[Y, Z, X];
[Z] ->
[Z, Y, X];
_ ->
split_2(X, Y, L, [], [])
end;
sort([_] = L) ->
L;
sort([] = L) ->
L.
sort_1(X, [Y | L], R) when X == Y ->
sort_1(Y, L, [X | R]);
sort_1(X, [Y | L], R) when X < Y ->
split_1(X, Y, L, R, []);
sort_1(X, [Y | L], R) ->
split_2(X, Y, L, R, []);
sort_1(X, [], R) ->
lists:reverse(R, [X]).
%% merge(List) -> L
%% merges a list of sorted lists
-spec merge([[T]]) -> [T].
merge(L) ->
mergel(L, []).
%% merge3(X, Y, Z) -> L
%% merges three sorted lists X, Y and Z
-spec merge3([_], [_], [_]) -> [_].
merge3(L1, [], L3) ->
merge(L1, L3);
merge3(L1, L2, []) ->
merge(L1, L2);
merge3(L1, [H2 | T2], [H3 | T3]) ->
lists:reverse(merge3_1(L1, [], H2, T2, H3, T3), []).
%% rmerge3(X, Y, Z) -> L
%% merges three reversed sorted lists X, Y and Z
-spec rmerge3([_], [_], [_]) -> [_].
rmerge3(L1, [], L3) ->
rmerge(L1, L3);
rmerge3(L1, L2, []) ->
rmerge(L1, L2);
rmerge3(L1, [H2 | T2], [H3 | T3]) ->
lists:reverse(rmerge3_1(L1, [], H2, T2, H3, T3), []).
%% merge(X, Y) -> L
%% merges two sorted lists X and Y
-spec merge([_], [_]) -> [_].
merge(T1, []) ->
T1;
merge(T1, [H2 | T2]) ->
lists:reverse(merge2_1(T1, H2, T2, []), []).
%% rmerge(X, Y) -> L
%% merges two reversed sorted lists X and Y
%% reverse(rmerge(reverse(A),reverse(B))) is equal to merge(I,A,B).
-spec rmerge([_], [_]) -> [_].
rmerge(T1, []) ->
T1;
rmerge(T1, [H2 | T2]) ->
lists:reverse(rmerge2_1(T1, H2, T2, []), []).
%% concat(L) concatenate the list representation of the elements
%% in L - the elements in L can be atoms, numbers of strings.
%% Returns a list of characters.
-type concat_thing() :: atom() | integer() | float() | string().
-spec concat([concat_thing()]) -> string().
concat(List) ->
flatmap(fun thing_to_list/1, List).
thing_to_list(X) when is_integer(X) -> integer_to_list(X);
thing_to_list(X) when is_float(X) -> float_to_list(X);
thing_to_list(X) when is_atom(X) -> atom_to_list(X);
thing_to_list(X) when is_list(X) -> X. %Assumed to be a string
%% flatten(List)
%% flatten(List, Tail)
%% Flatten a list, adding optional tail.
-spec flatten([_]) -> [_].
flatten(List) when is_list(List) ->
do_flatten(List, []).
-spec flatten([_], [_]) -> [_].
flatten(List, Tail) when is_list(List), is_list(Tail) ->
do_flatten(List, Tail).
do_flatten([H|T], Tail) when is_list(H) ->
do_flatten(H, do_flatten(T, Tail));
do_flatten([H|T], Tail) ->
[H|do_flatten(T, Tail)];
do_flatten([], Tail) ->
Tail.
%% flatlength(List)
%% Calculate the length of a list of lists.
-spec flatlength([_]) -> non_neg_integer().
flatlength(List) ->
flatlength(List, 0).
flatlength([H|T], L) when is_list(H) ->
flatlength(H, flatlength(T, L));
flatlength([_|T], L) ->
flatlength(T, L + 1);
flatlength([], L) -> L.
%% keymember(Key, Index, [Tuple]) Now a BIF!
%% keysearch(Key, Index, [Tuple]) Now a BIF!
%% keydelete(Key, Index, [Tuple])
%% keyreplace(Key, Index, [Tuple], NewTuple)
%% keytake(Key, Index, [Tuple])
%% keystore(Key, Index, [Tuple], NewTuple)
%% keysort(Index, [Tuple])
%% keymerge(Index, [Tuple], [Tuple])
%% ukeysort(Index, [Tuple])
%% ukeymerge(Index, [Tuple], [Tuple])
%% keymap(Function, Index, [Tuple])
%% keymap(Function, ExtraArgs, Index, [Tuple])
%keymember(K,N,L) when is_integer(N), N > 0 ->
% keymember3(K,N,L).
%keymember3(Key, N, [T|Ts]) when element(N, T) == Key -> true;
%keymember3(Key, N, [T|Ts]) ->
% keymember3(Key, N, Ts);
%keymember3(Key, N, []) -> false.
%keysearch(K, N, L) when is_integer(N), N > 0 ->
% keysearch3(K, N, L).
%keysearch3(Key, N, [H|T]) when element(N, H) == Key ->
% {value, H};
%keysearch3(Key, N, [H|T]) ->
% keysearch3(Key, N, T);
%keysearch3(Key, N, []) -> false.
-spec keydelete(_, pos_integer(), [T]) -> [T].
keydelete(K, N, L) when is_integer(N), N > 0 ->
keydelete3(K, N, L).
keydelete3(Key, N, [H|T]) when element(N, H) == Key -> T;
keydelete3(Key, N, [H|T]) ->
[H|keydelete3(Key, N, T)];
keydelete3(_, _, []) -> [].
-spec keyreplace(_, pos_integer(), [_], tuple()) -> [_].
keyreplace(K, N, L, New) when is_integer(N), N > 0, is_tuple(New) ->
keyreplace3(K, N, L, New).
keyreplace3(Key, Pos, [Tup|Tail], New) when element(Pos, Tup) == Key ->
[New|Tail];
keyreplace3(Key, Pos, [H|T], New) ->
[H|keyreplace3(Key, Pos, T, New)];
keyreplace3(_, _, [], _) -> [].
-spec keytake(_, pos_integer(), [_]) -> {'value', tuple(), [_]} | 'false'.
keytake(Key, N, L) when is_integer(N), N > 0 ->
keytake(Key, N, L, []).
keytake(Key, N, [H|T], L) when element(N, H) == Key ->
{value, H, lists:reverse(L, T)};
keytake(Key, N, [H|T], L) ->
keytake(Key, N, T, [H|L]);
keytake(_K, _N, [], _L) -> false.
-spec keystore(_, pos_integer(), [_], tuple()) -> [_].
keystore(K, N, L, New) when is_integer(N), N > 0, is_tuple(New) ->
keystore2(K, N, L, New).
keystore2(Key, N, [H|T], New) when element(N, H) == Key ->
[New|T];
keystore2(Key, N, [H|T], New) ->
[H|keystore2(Key, N, T, New)];
keystore2(_Key, _N, [], New) ->
[New].
-spec keysort(pos_integer(), [T]) -> [T] when is_subtype(T, tuple()).
keysort(I, L) when is_integer(I), I > 0 ->
case L of
[] -> L;
[_] -> L;
[X, Y | T] ->
case {element(I, X), element(I, Y)} of
{EX, EY} when EX =< EY ->
case T of
[] ->
L;
[Z] ->
case element(I, Z) of
EZ when EY =< EZ ->
L;
EZ when EX =< EZ ->
[X, Z, Y];
_EZ ->
[Z, X, Y]
end;
_ when X == Y ->
keysort_1(I, Y, EY, T, [X]);
_ ->
keysplit_1(I, X, EX, Y, EY, T, [], [])
end;
{EX, EY} ->
case T of
[] ->
[Y, X];
[Z] ->
case element(I, Z) of
EZ when EX =< EZ ->
[Y, X | T];
EZ when EY =< EZ ->
[Y, Z, X];
_EZ ->
[Z, Y, X]
end;
_ ->
keysplit_2(I, X, EX, Y, EY, T, [], [])
end
end
end.
keysort_1(I, X, EX, [Y | L], R) when X == Y ->
keysort_1(I, Y, EX, L, [X | R]);
keysort_1(I, X, EX, [Y | L], R) ->
case element(I, Y) of
EY when EX =< EY ->
keysplit_1(I, X, EX, Y, EY, L, R, []);
EY ->
keysplit_2(I, X, EX, Y, EY, L, R, [])
end;
keysort_1(_I, X, _EX, [], R) ->
lists:reverse(R, [X]).
-spec keymerge(pos_integer(), [X], [Y]) ->
[R] when is_subtype(X, tuple()), is_subtype(Y, tuple()), is_subtype(R, tuple()).
keymerge(Index, T1, L2) when is_integer(Index), Index > 0 ->
case L2 of
[] ->
T1;
[H2 | T2] ->
E2 = element(Index, H2),
M = keymerge2_1(Index, T1, E2, H2, T2, []),
lists:reverse(M, [])
end.
%% reverse(rkeymerge(I,reverse(A),reverse(B))) is equal to keymerge(I,A,B).
-spec rkeymerge(pos_integer(), [X], [Y]) ->
[R] when is_subtype(X, tuple()), is_subtype(Y, tuple()), is_subtype(R, tuple()).
rkeymerge(Index, T1, L2) when is_integer(Index), Index > 0 ->
case L2 of
[] ->
T1;
[H2 | T2] ->
E2 = element(Index, H2),
M = rkeymerge2_1(Index, T1, E2, H2, T2, []),
lists:reverse(M, [])
end.
-spec ukeysort(pos_integer(), [T]) -> [T] when is_subtype(T, tuple()).
ukeysort(I, L) when is_integer(I), I > 0 ->
case L of
[] -> L;
[_] -> L;
[X, Y | T] ->
case {element(I, X), element(I, Y)} of
{EX, EY} when EX == EY ->
ukeysort_1(I, X, EX, T);
{EX, EY} when EX < EY ->
case T of
[] ->
L;
[Z] ->
case element(I, Z) of
EZ when EY == EZ ->
[X, Y];
EZ when EY < EZ ->
[X, Y, Z];
EZ when EZ == EX ->
[X, Y];
EZ when EX =< EZ ->
[X, Z, Y];
_EZ ->
[Z, X, Y]
end;
_ ->
ukeysplit_1(I, X, EX, Y, EY, T, [], [])
end;
{EX, EY} ->
case T of
[] ->
[Y, X];
[Z] ->
case element(I, Z) of
EZ when EX == EZ ->
[Y, X];
EZ when EX < EZ ->
[Y, X, Z];
EZ when EY == EZ ->
[Y, X];
EZ when EY =< EZ ->
[Y, Z, X];
_EZ ->
[Z, Y, X]
end;
_ ->
ukeysplit_2(I, Y, EY, T, [X])
end
end
end.
ukeysort_1(I, X, EX, [Y | L]) ->
case element(I, Y) of
EY when EX == EY ->
ukeysort_1(I, X, EX, L);
EY when EX < EY ->
ukeysplit_1(I, X, EX, Y, EY, L, [], []);
EY ->
ukeysplit_2(I, Y, EY, L, [X])
end;
ukeysort_1(_I, X, _EX, []) ->
[X].
-spec ukeymerge(pos_integer(), [X], [Y]) ->
[(X | Y)] when is_subtype(X, tuple()), is_subtype(Y, tuple()).
ukeymerge(Index, L1, T2) when is_integer(Index), Index > 0 ->
case L1 of
[] ->
T2;
[H1 | T1] ->
E1 = element(Index, H1),
M = ukeymerge2_2(Index, T1, E1, H1, T2, []),
lists:reverse(M, [])
end.
%% reverse(rukeymerge(I,reverse(A),reverse(B))) is equal to ukeymerge(I,A,B).
-spec rukeymerge(pos_integer(), [X], [Y]) ->
[(X | Y)] when is_subtype(X, tuple()), is_subtype(Y, tuple()).
rukeymerge(Index, T1, L2) when is_integer(Index), Index > 0 ->
case L2 of
[] ->
T1;
[H2 | T2] ->
E2 = element(Index, H2),
M = rukeymerge2_1(Index, T1, E2, T2, [], H2),
lists:reverse(M, [])
end.
-spec keymap(fun((_) -> _), pos_integer(), [tuple()]) -> [tuple()].
keymap(Fun, Index, [Tup|Tail]) ->
[setelement(Index, Tup, Fun(element(Index, Tup)))|keymap(Fun, Index, Tail)];
keymap(Fun, Index, []) when is_integer(Index), Index >= 1,
is_function(Fun, 1) -> [].
%%% Suggestion from OTP-2948: sort and merge with Fun.
-spec sort(fun((T, T) -> boolean()), [T]) -> [T].
sort(Fun, []) when is_function(Fun, 2) ->
[];
sort(Fun, [_] = L) when is_function(Fun, 2) ->
L;
sort(Fun, [X, Y | T]) ->
case Fun(X, Y) of
true ->
fsplit_1(Y, X, Fun, T, [], []);
false ->
fsplit_2(Y, X, Fun, T, [], [])
end.
-spec merge(fun((X, Y) -> boolean()), [X], [Y]) -> [_].
merge(Fun, T1, [H2 | T2]) when is_function(Fun, 2) ->
lists:reverse(fmerge2_1(T1, H2, Fun, T2, []), []);
merge(Fun, T1, []) when is_function(Fun, 2) ->
T1.
%% reverse(rmerge(F,reverse(A),reverse(B))) is equal to merge(F,A,B).
-spec rmerge(fun((X, Y) -> boolean()), [X], [Y]) -> [_].
rmerge(Fun, T1, [H2 | T2]) when is_function(Fun, 2) ->
lists:reverse(rfmerge2_1(T1, H2, Fun, T2, []), []);
rmerge(Fun, T1, []) when is_function(Fun, 2) ->
T1.
-spec usort(fun((T, T) -> boolean()), [T]) -> [T].
usort(Fun, [_] = L) when is_function(Fun, 2) ->
L;
usort(Fun, [] = L) when is_function(Fun, 2) ->
L;
usort(Fun, [X | L]) when is_function(Fun, 2) ->
usort_1(Fun, X, L).
usort_1(Fun, X, [Y | L]) ->
case Fun(X, Y) of
true ->
case Fun(Y, X) of
true -> % X equal to Y
case L of
[] ->
[X];
_ ->
usort_1(Fun, X, L)
end;
false ->
ufsplit_1(Y, X, Fun, L, [], [])
end;
false ->
ufsplit_2(Y, L, Fun, [X])
end.
-spec umerge(fun((X, Y) -> boolean()), [X], [Y]) -> [_].
umerge(Fun, [], T2) when is_function(Fun, 2) ->
T2;
umerge(Fun, [H1 | T1], T2) when is_function(Fun, 2) ->
lists:reverse(ufmerge2_2(H1, T1, Fun, T2, []), []).
%% reverse(rumerge(F,reverse(A),reverse(B))) is equal to umerge(F,A,B).
-spec rumerge(fun((X, Y) -> boolean()), [X], [Y]) -> [_].
rumerge(Fun, T1, []) when is_function(Fun, 2) ->
T1;
rumerge(Fun, T1, [H2 | T2]) when is_function(Fun, 2) ->
lists:reverse(rufmerge2_1(T1, H2, Fun, T2, []), []).
%% usort(List) -> L
%% sorts the list L, removes duplicates
-spec usort([T]) -> [T].
usort([X, Y | L] = L0) when X < Y ->
case L of
[] ->
L0;
[Z] when Y < Z ->
L0;
[Z] when Y == Z ->
[X, Y];
[Z] when Z < X ->
[Z, X, Y];
[Z] when Z == X ->
[X, Y];
[Z] ->
[X, Z, Y];
_ ->
usplit_1(X, Y, L, [], [])
end;
usort([X, Y | L]) when X > Y ->
case L of
[] ->
[Y, X];
[Z] when X < Z ->
[Y, X | L];
[Z] when X == Z ->
[Y, X];
[Z] when Z < Y ->
[Z, Y, X];
[Z] when Z == Y ->
[Y, X];
[Z] ->
[Y, Z, X];
_ ->
usplit_2(X, Y, L, [], [])
end;
usort([X, _Y | L]) ->
usort_1(X, L);
usort([_] = L) ->
L;
usort([]) ->
[].
usort_1(X, [Y | L]) when X == Y ->
usort_1(X, L);
usort_1(X, [Y | L]) when X < Y ->
usplit_1(X, Y, L, [], []);
usort_1(X, [Y | L]) ->
usplit_2(X, Y, L, [], []);
usort_1(X, []) ->
[X].
%% umerge(List) -> L
%% merges a list of sorted lists without duplicates, removes duplicates
-spec umerge([[T]]) -> [T].
umerge(L) ->
umergel(L).
%% umerge3(X, Y, Z) -> L
%% merges three sorted lists X, Y and Z without duplicates,
%% removes duplicates
-spec umerge3([_], [_], [_]) -> [_].
umerge3(L1, [], L3) ->
umerge(L1, L3);
umerge3(L1, L2, []) ->
umerge(L1, L2);
umerge3(L1, [H2 | T2], [H3 | T3]) ->
lists:reverse(umerge3_1(L1, [H2 | H3], T2, H2, [], T3, H3), []).
%% rumerge3(X, Y, Z) -> L
%% merges three reversed sorted lists X, Y and Z without duplicates,
%% removes duplicates
-spec rumerge3([_], [_], [_]) -> [_].
rumerge3(L1, [], L3) ->
rumerge(L1, L3);
rumerge3(L1, L2, []) ->
rumerge(L1, L2);
rumerge3(L1, [H2 | T2], [H3 | T3]) ->
lists:reverse(rumerge3_1(L1, T2, H2, [], T3, H3),[]).
%% umerge(X, Y) -> L
%% merges two sorted lists X and Y without duplicates, removes duplicates
-spec umerge([_], [_]) -> [_].
umerge([], T2) ->
T2;
umerge([H1 | T1], T2) ->
lists:reverse(umerge2_2(T1, T2, [], H1), []).
%% rumerge(X, Y) -> L
%% merges two reversed sorted lists X and Y without duplicates,
%% removes duplicates
%% reverse(rumerge(reverse(A),reverse(B))) is equal to umerge(I,A,B).
-spec rumerge([_], [_]) -> [_].
rumerge(T1, []) ->
T1;
rumerge(T1, [H2 | T2]) ->
lists:reverse(rumerge2_1(T1, T2, [], H2), []).
%% all(Predicate, List)
%% any(Predicate, List)
%% map(Function, List)
%% flatmap(Function, List)
%% foldl(Function, First, List)
%% foldr(Function, Last, List)
%% filter(Predicate, List)
%% zf(Function, List)
%% mapfoldl(Function, First, List)
%% mapfoldr(Function, Last, List)
%% foreach(Function, List)
%% takewhile(Predicate, List)
%% dropwhile(Predicate, List)
%% splitwith(Predicate, List)
%% for list programming. Function here is a 'fun'. For backward compatibility,
%% {Module,Function} is still accepted.
%%
%% The name zf is a joke!
%%
%% N.B. Unless where the functions actually needs it only foreach/2/3,
%% which is meant to be used for its side effects, has a defined order
%% of evaluation.
%%
%% There are also versions with an extra argument, ExtraArgs, which is a
%% list of extra arguments to each call.
-spec all(fun((T) -> boolean()), [T]) -> boolean().
all(Pred, [Hd|Tail]) ->
case Pred(Hd) of
true -> all(Pred, Tail);
false -> false
end;
all(Pred, []) when is_function(Pred, 1) -> true.
-spec any(fun((T) -> boolean()), [T]) -> boolean().
any(Pred, [Hd|Tail]) ->
case Pred(Hd) of
true -> true;
false -> any(Pred, Tail)
end;
any(Pred, []) when is_function(Pred, 1) -> false.
-spec map(fun((D) -> R), [D]) -> [R].
map(F, [H|T]) ->
[F(H)|map(F, T)];
map(F, []) when is_function(F, 1) -> [].
-spec flatmap(fun((D) -> [R]), [D]) -> [R].
flatmap(F, [Hd|Tail]) ->
F(Hd) ++ flatmap(F, Tail);
flatmap(F, []) when is_function(F, 1) -> [].
-spec foldl(fun((T, _) -> _), _, [T]) -> _.
foldl(F, Accu, [Hd|Tail]) ->
foldl(F, F(Hd, Accu), Tail);
foldl(F, Accu, []) when is_function(F, 2) -> Accu.
-spec foldr(fun((T, _) -> _), _, [T]) -> _.
foldr(F, Accu, [Hd|Tail]) ->
F(Hd, foldr(F, Accu, Tail));
foldr(F, Accu, []) when is_function(F, 2) -> Accu.
-spec filter(Pred :: fun((T) -> boolean()), List :: [T]) -> [T].
filter(Pred, List) when is_function(Pred, 1) ->
[ E || E <- List, Pred(E) ].
%% Equivalent to {filter(F, L), filter(NotF, L)}, if NotF = 'fun(X) ->
%% not F(X) end'.
-spec partition(Pred :: fun((T) -> boolean()), List :: [T]) -> {[T], [T]}.
partition(Pred, L) ->
partition(Pred, L, [], []).
partition(Pred, [H | T], As, Bs) ->
case Pred(H) of
true -> partition(Pred, T, [H | As], Bs);
false -> partition(Pred, T, As, [H | Bs])
end;
partition(Pred, [], As, Bs) when is_function(Pred, 1) ->
{reverse(As), reverse(Bs)}.
-spec zf(fun((T) -> boolean() | {'true', X}), [T]) -> [(T | X)].
zf(F, [Hd|Tail]) ->
case F(Hd) of
true ->
[Hd|zf(F, Tail)];
{true,Val} ->
[Val|zf(F, Tail)];
false ->
zf(F, Tail)
end;
zf(F, []) when is_function(F, 1) -> [].
-spec foreach(F :: fun((T) -> _), List :: [T]) -> 'ok'.
foreach(F, [Hd|Tail]) ->
F(Hd),
foreach(F, Tail);
foreach(F, []) when is_function(F, 1) -> ok.
-spec mapfoldl(fun((T, _) -> {_, _}), _, [T]) -> {[_], _}.
mapfoldl(F, Accu0, [Hd|Tail]) ->
{R,Accu1} = F(Hd, Accu0),
{Rs,Accu2} = mapfoldl(F, Accu1, Tail),
{[R|Rs],Accu2};
mapfoldl(F, Accu, []) when is_function(F, 2) -> {[],Accu}.
-spec mapfoldr(fun((T, _) -> {_, _}), _, [T]) -> {[_], _}.
mapfoldr(F, Accu0, [Hd|Tail]) ->
{Rs,Accu1} = mapfoldr(F, Accu0, Tail),
{R,Accu2} = F(Hd, Accu1),
{[R|Rs],Accu2};
mapfoldr(F, Accu, []) when is_function(F, 2) -> {[],Accu}.
-spec takewhile(fun((T) -> boolean()), [T]) -> [T].
takewhile(Pred, [Hd|Tail]) ->
case Pred(Hd) of
true -> [Hd|takewhile(Pred, Tail)];
false -> []
end;
takewhile(Pred, []) when is_function(Pred, 1) -> [].
-spec dropwhile(fun((T) -> boolean()), [T]) -> [T].
dropwhile(Pred, [Hd|Tail]=Rest) ->
case Pred(Hd) of
true -> dropwhile(Pred, Tail);
false -> Rest
end;
dropwhile(Pred, []) when is_function(Pred, 1) -> [].
-spec splitwith(fun((T) -> boolean()), [T]) -> {[T], [T]}.
splitwith(Pred, List) when is_function(Pred, 1) ->
splitwith(Pred, List, []).
splitwith(Pred, [Hd|Tail], Taken) ->
case Pred(Hd) of
true -> splitwith(Pred, Tail, [Hd|Taken]);
false -> {reverse(Taken), [Hd|Tail]}
end;
splitwith(Pred, [], Taken) when is_function(Pred, 1) ->
{reverse(Taken),[]}.
-spec split(non_neg_integer(), [T]) -> {[T], [T]}.
split(N, List) when is_integer(N), N >= 0, is_list(List) ->
case split(N, List, []) of
{_, _} = Result -> Result;
Fault when is_atom(Fault) ->
erlang:error(Fault, [N,List])
end;
split(N, List) ->
erlang:error(badarg, [N,List]).
split(0, L, R) ->
{lists:reverse(R, []), L};
split(N, [H|T], R) ->
split(N-1, T, [H|R]);
split(_, [], _) ->
badarg.
%%% =================================================================
%%% Here follows the implementation of the sort functions.
%%%
%%% These functions used to be in their own module (lists_sort),
%%% but have now been placed here to allow Dialyzer to produce better
%%% type information.
%%% =================================================================
-compile({inline,
[{merge3_12,7}, {merge3_21,7}, {rmerge3_12,7}, {rmerge3_21,7}]}).
-compile({inline,
[{umerge3_12,8}, {umerge3_21,8},
{rumerge3_12a,7}, {rumerge3_12b,8}]}).
-compile({inline,
[{keymerge3_12,12}, {keymerge3_21,12},
{rkeymerge3_12,12}, {rkeymerge3_21,12}]}).
-compile({inline,
[{ukeymerge3_12,13}, {ukeymerge3_21,13},
{rukeymerge3_12a,11}, {rukeymerge3_21a,13},
{rukeymerge3_12b,12}, {rukeymerge3_21b,12}]}).
%% sort/1
%% Ascending.
split_1(X, Y, [Z | L], R, Rs) when Z >= Y ->
split_1(Y, Z, L, [X | R], Rs);
split_1(X, Y, [Z | L], R, Rs) when Z >= X ->
split_1(Z, Y, L, [X | R], Rs);
split_1(X, Y, [Z | L], [], Rs) ->
split_1(X, Y, L, [Z], Rs);
split_1(X, Y, [Z | L], R, Rs) ->
split_1_1(X, Y, L, R, Rs, Z);
split_1(X, Y, [], R, Rs) ->
rmergel([[Y, X | R] | Rs], []).
split_1_1(X, Y, [Z | L], R, Rs, S) when Z >= Y ->
split_1_1(Y, Z, L, [X | R], Rs, S);
split_1_1(X, Y, [Z | L], R, Rs, S) when Z >= X ->
split_1_1(Z, Y, L, [X | R], Rs, S);
split_1_1(X, Y, [Z | L], R, Rs, S) when S =< Z ->
split_1(S, Z, L, [], [[Y, X | R] | Rs]);
split_1_1(X, Y, [Z | L], R, Rs, S) ->
split_1(Z, S, L, [], [[Y, X | R] | Rs]);
split_1_1(X, Y, [], R, Rs, S) ->
rmergel([[S], [Y, X | R] | Rs], []).
%% Descending.
split_2(X, Y, [Z | L], R, Rs) when Z =< Y ->
split_2(Y, Z, L, [X | R], Rs);
split_2(X, Y, [Z | L], R, Rs) when Z =< X ->
split_2(Z, Y, L, [X | R], Rs);
split_2(X, Y, [Z | L], [], Rs) ->
split_2(X, Y, L, [Z], Rs);
split_2(X, Y, [Z | L], R, Rs) ->
split_2_1(X, Y, L, R, Rs, Z);
split_2(X, Y, [], R, Rs) ->
mergel([[Y, X | R] | Rs], []).
split_2_1(X, Y, [Z | L], R, Rs, S) when Z =< Y ->
split_2_1(Y, Z, L, [X | R], Rs, S);
split_2_1(X, Y, [Z | L], R, Rs, S) when Z =< X ->
split_2_1(Z, Y, L, [X | R], Rs, S);
split_2_1(X, Y, [Z | L], R, Rs, S) when S > Z ->
split_2(S, Z, L, [], [[Y, X | R] | Rs]);
split_2_1(X, Y, [Z | L], R, Rs, S) ->
split_2(Z, S, L, [], [[Y, X | R] | Rs]);
split_2_1(X, Y, [], R, Rs, S) ->
mergel([[S], [Y, X | R] | Rs], []).
%% merge/1
mergel([[] | L], Acc) ->
mergel(L, Acc);
mergel([T1, [H2 | T2], [H3 | T3] | L], Acc) ->
mergel(L, [merge3_1(T1, [], H2, T2, H3, T3) | Acc]);
mergel([T1, [H2 | T2]], Acc) ->
rmergel([merge2_1(T1, H2, T2, []) | Acc], []);
mergel([L], []) ->
L;
mergel([L], Acc) ->
rmergel([lists:reverse(L, []) | Acc], []);
mergel([], []) ->
[];
mergel([], Acc) ->
rmergel(Acc, []);
mergel([A, [] | L], Acc) ->
mergel([A | L], Acc);
mergel([A, B, [] | L], Acc) ->
mergel([A, B | L], Acc).
rmergel([[H3 | T3], [H2 | T2], T1 | L], Acc) ->
rmergel(L, [rmerge3_1(T1, [], H2, T2, H3, T3) | Acc]);
rmergel([[H2 | T2], T1], Acc) ->
mergel([rmerge2_1(T1, H2, T2, []) | Acc], []);
rmergel([L], Acc) ->
mergel([lists:reverse(L, []) | Acc], []);
rmergel([], Acc) ->
mergel(Acc, []).
%% merge3/3
%% Take L1 apart.
merge3_1([H1 | T1], M, H2, T2, H3, T3) when H1 =< H2 ->
merge3_12(T1, H1, H2, T2, H3, T3, M);
merge3_1([H1 | T1], M, H2, T2, H3, T3) ->
merge3_21(T1, H1, H2, T2, H3, T3, M);
merge3_1([], M, H2, T2, H3, T3) when H2 =< H3 ->
merge2_1(T2, H3, T3, [H2 | M]);
merge3_1([], M, H2, T2, H3, T3) ->
merge2_2(T2, H3, T3, M, H2).
%% Take L2 apart.
merge3_2(T1, H1, M, [H2 | T2], H3, T3) when H1 =< H2 ->
merge3_12(T1, H1, H2, T2, H3, T3, M);
merge3_2(T1, H1, M, [H2 | T2], H3, T3) ->
merge3_21(T1, H1, H2, T2, H3, T3, M);
merge3_2(T1, H1, M, [], H3, T3) when H1 =< H3 ->
merge2_1(T1, H3, T3, [H1 | M]);
merge3_2(T1, H1, M, [], H3, T3) ->
merge2_2(T1, H3, T3, M, H1).
% H1 =< H2. Inlined.
merge3_12(T1, H1, H2, T2, H3, T3, M) when H1 =< H3 ->
merge3_1(T1, [H1 | M], H2, T2, H3, T3);
merge3_12(T1, H1, H2, T2, H3, T3, M) ->
merge3_12_3(T1, H1, H2, T2, [H3 | M], T3).
% H1 =< H2, take L3 apart.
merge3_12_3(T1, H1, H2, T2, M, [H3 | T3]) when H1 =< H3 ->
merge3_1(T1, [H1 | M], H2, T2, H3, T3);
merge3_12_3(T1, H1, H2, T2, M, [H3 | T3]) ->
merge3_12_3(T1, H1, H2, T2, [H3 | M], T3);
merge3_12_3(T1, H1, H2, T2, M, []) ->
merge2_1(T1, H2, T2, [H1 | M]).
% H1 > H2. Inlined.
merge3_21(T1, H1, H2, T2, H3, T3, M) when H2 =< H3 ->
merge3_2(T1, H1, [H2 | M], T2, H3, T3);
merge3_21(T1, H1, H2, T2, H3, T3, M) ->
merge3_21_3(T1, H1, H2, T2, [H3 | M], T3).
% H1 > H2, take L3 apart.
merge3_21_3(T1, H1, H2, T2, M, [H3 | T3]) when H2 =< H3 ->
merge3_2(T1, H1, [H2 | M], T2, H3, T3);
merge3_21_3(T1, H1, H2, T2, M, [H3 | T3]) ->
merge3_21_3(T1, H1, H2, T2, [H3 | M], T3);
merge3_21_3(T1, H1, H2, T2, M, []) ->
merge2_2(T1, H2, T2, M, H1).
%% rmerge/3
%% Take L1 apart.
rmerge3_1([H1 | T1], M, H2, T2, H3, T3) when H1 =< H2 ->
rmerge3_12(T1, H1, H2, T2, H3, T3, M);
rmerge3_1([H1 | T1], M, H2, T2, H3, T3) ->
rmerge3_21(T1, H1, H2, T2, H3, T3, M);
rmerge3_1([], M, H2, T2, H3, T3) when H2 =< H3 ->
rmerge2_2(T2, H3, T3, M, H2);
rmerge3_1([], M, H2, T2, H3, T3) ->
rmerge2_1(T2, H3, T3, [H2 | M]).
%% Take L2 apart.
rmerge3_2(T1, H1, M, [H2 | T2], H3, T3) when H1 =< H2 ->
rmerge3_12(T1, H1, H2, T2, H3, T3, M);
rmerge3_2(T1, H1, M, [H2 | T2], H3, T3) ->
rmerge3_21(T1, H1, H2, T2, H3, T3, M);
rmerge3_2(T1, H1, M, [], H3, T3) when H1 =< H3 ->
rmerge2_2(T1, H3, T3, M, H1);
rmerge3_2(T1, H1, M, [], H3, T3) ->
rmerge2_1(T1, H3, T3, [H1 | M]).
% H1 =< H2. Inlined.
rmerge3_12(T1, H1, H2, T2, H3, T3, M) when H2 =< H3 ->
rmerge3_12_3(T1, H1, H2, T2, [H3 | M], T3);
rmerge3_12(T1, H1, H2, T2, H3, T3, M) ->
rmerge3_2(T1, H1, [H2 | M], T2, H3, T3).
% H1 =< H2, take L3 apart.
rmerge3_12_3(T1, H1, H2, T2, M, [H3 | T3]) when H2 =< H3 ->
rmerge3_12_3(T1, H1, H2, T2, [H3 | M], T3);
rmerge3_12_3(T1, H1, H2, T2, M, [H3 | T3]) ->
rmerge3_2(T1, H1, [H2 | M], T2, H3, T3);
rmerge3_12_3(T1, H1, H2, T2, M, []) ->
rmerge2_2(T1, H2, T2, M, H1).
% H1 > H2. Inlined.
rmerge3_21(T1, H1, H2, T2, H3, T3, M) when H1 =< H3 ->
rmerge3_21_3(T1, H1, H2, T2, [H3 | M], T3);
rmerge3_21(T1, H1, H2, T2, H3, T3, M) ->
rmerge3_1(T1, [H1 | M], H2, T2, H3, T3).
% H1 > H2, take L3 apart.
rmerge3_21_3(T1, H1, H2, T2, M, [H3 | T3]) when H1 =< H3 ->
rmerge3_21_3(T1, H1, H2, T2, [H3 | M], T3);
rmerge3_21_3(T1, H1, H2, T2, M, [H3 | T3]) ->
rmerge3_1(T1, [H1 | M], H2, T2, H3, T3);
rmerge3_21_3(T1, H1, H2, T2, M, []) ->
rmerge2_1(T1, H2, T2, [H1 | M]).
%% merge/2
merge2_1([H1 | T1], H2, T2, M) when H1 =< H2 ->
merge2_1(T1, H2, T2, [H1 | M]);
merge2_1([H1 | T1], H2, T2, M) ->
merge2_2(T1, H2, T2, M, H1);
merge2_1([], H2, T2, M) ->
lists:reverse(T2, [H2 | M]).
merge2_2(T1, HdM, [H2 | T2], M, H1) when H1 =< H2 ->
merge2_1(T1, H2, T2, [H1, HdM | M]);
merge2_2(T1, HdM, [H2 | T2], M, H1) ->
merge2_2(T1, H2, T2, [HdM | M], H1);
merge2_2(T1, HdM, [], M, H1) ->
lists:reverse(T1, [H1, HdM | M]).
%% rmerge/2
rmerge2_1([H1 | T1], H2, T2, M) when H1 =< H2 ->
rmerge2_2(T1, H2, T2, M, H1);
rmerge2_1([H1 | T1], H2, T2, M) ->
rmerge2_1(T1, H2, T2, [H1 | M]);
rmerge2_1([], H2, T2, M) ->
lists:reverse(T2, [H2 | M]).
rmerge2_2(T1, HdM, [H2 | T2], M, H1) when H1 =< H2 ->
rmerge2_2(T1, H2, T2, [HdM | M], H1);
rmerge2_2(T1, HdM, [H2 | T2], M, H1) ->
rmerge2_1(T1, H2, T2, [H1, HdM | M]);
rmerge2_2(T1, HdM, [], M, H1) ->
lists:reverse(T1, [H1, HdM | M]).
%% usort/1
%% Ascending.
usplit_1(X, Y, [Z | L], R, Rs) when Z > Y ->
usplit_1(Y, Z, L, [X | R], Rs);
usplit_1(X, Y, [Z | L], R, Rs) when Z == Y ->
usplit_1(X, Y, L, R, Rs);
usplit_1(X, Y, [Z | L], R, Rs) when Z > X ->
usplit_1(Z, Y, L, [X | R], Rs);
usplit_1(X, Y, [Z | L], R, Rs) when Z == X ->
usplit_1(X, Y, L, R, Rs);
usplit_1(X, Y, [Z | L], [], Rs) ->
usplit_1(X, Y, L, [Z], Rs);
usplit_1(X, Y, [Z | L], R, Rs) ->
usplit_1_1(X, Y, L, R, Rs, Z);
usplit_1(X, Y, [], R, Rs) ->
rumergel([[Y, X | R] | Rs], [], asc).
usplit_1_1(X, Y, [Z | L], R, Rs, S) when Z > Y ->
usplit_1_1(Y, Z, L, [X | R], Rs, S);
usplit_1_1(X, Y, [Z | L], R, Rs, S) when Z == Y ->
usplit_1_1(X, Y, L, R, Rs, S);
usplit_1_1(X, Y, [Z | L], R, Rs, S) when Z > X ->
usplit_1_1(Z, Y, L, [X | R], Rs, S);
usplit_1_1(X, Y, [Z | L], R, Rs, S) when Z == X ->
usplit_1_1(X, Y, L, R, Rs, S);
usplit_1_1(X, Y, [Z | L], R, Rs, S) when Z > S ->
usplit_1(S, Z, L, [], [[Y, X | R] | Rs]);
usplit_1_1(X, Y, [Z | L], R, Rs, S) when Z == S ->
usplit_1_1(X, Y, L, R, Rs, S);
usplit_1_1(X, Y, [Z | L], R, Rs, S) ->
usplit_1(Z, S, L, [], [[Y, X | R] | Rs]);
usplit_1_1(X, Y, [], R, Rs, S) ->
rumergel([[S], [Y, X | R] | Rs], [], asc).
%% Descending.
usplit_2(X, Y, [Z | L], R, Rs) when Z < Y ->
usplit_2(Y, Z, L, [X | R], Rs);
usplit_2(X, Y, [Z | L], R, Rs) when Z == Y ->
usplit_2(X, Y, L, R, Rs);
usplit_2(X, Y, [Z | L], R, Rs) when Z < X ->
usplit_2(Z, Y, L, [X | R], Rs);
usplit_2(X, Y, [Z | L], R, Rs) when Z == X ->
usplit_2(X, Y, L, R, Rs);
usplit_2(X, Y, [Z | L], [], Rs) ->
usplit_2(X, Y, L, [Z], Rs);
usplit_2(X, Y, [Z | L], R, Rs) ->
usplit_2_1(X, Y, L, R, Rs, Z);
usplit_2(X, Y, [], R, Rs) ->
umergel([[Y, X | R] | Rs], [], desc).
usplit_2_1(X, Y, [Z | L], R, Rs, S) when Z < Y ->
usplit_2_1(Y, Z, L, [X | R], Rs, S);
usplit_2_1(X, Y, [Z | L], R, Rs, S) when Z == Y ->
usplit_2_1(X, Y, L, R, Rs, S);
usplit_2_1(X, Y, [Z | L], R, Rs, S) when Z < X ->
usplit_2_1(Z, Y, L, [X | R], Rs, S);
usplit_2_1(X, Y, [Z | L], R, Rs, S) when Z == X ->
usplit_2_1(X, Y, L, R, Rs, S);
usplit_2_1(X, Y, [Z | L], R, Rs, S) when Z < S ->
usplit_2(S, Z, L, [], [[Y, X | R] | Rs]);
usplit_2_1(X, Y, [Z | L], R, Rs, S) when Z == S ->
usplit_2_1(X, Y, L, R, Rs, S);
usplit_2_1(X, Y, [Z | L], R, Rs, S) ->
usplit_2(Z, S, L, [], [[Y, X | R] | Rs]);
usplit_2_1(X, Y, [], R, Rs, S) ->
umergel([[S], [Y, X | R] | Rs], [], desc).
%% umerge/1
umergel(L) ->
umergel(L, [], asc).
umergel([[] | L], Acc, O) ->
umergel(L, Acc, O);
umergel([T1, [H2 | T2], [H3 | T3] | L], Acc, asc) ->
umergel(L, [umerge3_1(T1, [H2 | H3], T2, H2, [], T3, H3) | Acc], asc);
umergel([[H3 | T3], [H2 | T2], T1 | L], Acc, desc) ->
umergel(L, [umerge3_1(T1, [H2 | H3], T2, H2, [], T3, H3) | Acc], desc);
umergel([A, [] | L], Acc, O) ->
umergel([A | L], Acc, O);
umergel([A, B, [] | L], Acc, O) ->
umergel([A, B | L], Acc, O);
umergel([[H1 | T1], T2 | L], Acc, asc) ->
umergel(L, [umerge2_2(T1, T2, [], H1) | Acc], asc);
umergel([T2, [H1 | T1] | L], Acc, desc) ->
umergel(L, [umerge2_2(T1, T2, [], H1) | Acc], desc);
umergel([L], [], _O) ->
L;
umergel([L], Acc, O) ->
rumergel([lists:reverse(L, []) | Acc], [], O);
umergel([], [], _O) ->
[];
umergel([], Acc, O) ->
rumergel(Acc, [], O).
rumergel([[H3 | T3], [H2 | T2], T1 | L], Acc, asc) ->
rumergel(L, [rumerge3_1(T1, T2, H2, [], T3, H3) | Acc], asc);
rumergel([T1, [H2 | T2], [H3 | T3] | L], Acc, desc) ->
rumergel(L, [rumerge3_1(T1, T2, H2, [], T3, H3) | Acc], desc);
rumergel([[H2 | T2], T1 | L], Acc, asc) ->
rumergel(L, [rumerge2_1(T1, T2, [], H2) | Acc], asc);
rumergel([T1, [H2 | T2] | L], Acc, desc) ->
rumergel(L, [rumerge2_1(T1, T2, [], H2) | Acc], desc);
rumergel([L], Acc, O) ->
umergel([lists:reverse(L, []) | Acc], [], O);
rumergel([], Acc, O) ->
umergel(Acc, [], O).
%% umerge3/3
%% Take L1 apart.
umerge3_1([H1 | T1], HdM, T2, H2, M, T3, H3) when H1 =< H2 ->
umerge3_12(T1, H1, T2, H2, M, T3, H3, HdM);
umerge3_1([H1 | T1], HdM, T2, H2, M, T3, H3) when H2 == HdM ->
umerge3_2(T1, H1, T2, H2, M, T3, H3);
umerge3_1([H1 | T1], HdM, T2, H2, M, T3, H3) ->
umerge3_21(T1, H1, T2, H2, M, T3, H3, HdM);
umerge3_1([], HdM, T2, H2, M, T3, H3) when H2 == HdM ->
umerge2_1(T2, T3, M, HdM, H3);
umerge3_1([], _HdM, T2, H2, M, T3, H3) when H2 =< H3 ->
umerge2_1(T2, T3, [H2 | M], H2, H3);
umerge3_1([], HdM, T2, H2, M, T3, H3) when H3 == HdM ->
umerge2_2(T2, T3, M, H2);
umerge3_1([], _HdM, T2, H2, M, T3, H3) ->
umerge2_2(T2, T3, [H3 | M], H2).
%% Take L2 apart.
umerge3_2(T1, H1, [H2 | T2], HdM, M, T3, H3) when H1 =< H2 ->
umerge3_12(T1, H1, T2, H2, M, T3, H3, HdM);
umerge3_2(T1, H1, [H2 | T2], HdM, M, T3, H3) ->
umerge3_21(T1, H1, T2, H2, M, T3, H3, HdM);
umerge3_2(T1, H1, [], _HdM, M, T3, H3) when H1 =< H3 ->
umerge2_1(T1, T3, [H1 | M], H1, H3);
umerge3_2(T1, H1, [], HdM, M, T3, H3) when H3 == HdM ->
umerge2_2(T1, T3, M, H1);
umerge3_2(T1, H1, [], _HdM, M, T3, H3) ->
umerge2_2(T1, T3, [H3 | M], H1).
% H1 =< H2. Inlined.
umerge3_12(T1, H1, T2, H2, M, T3, H3, _HdM) when H1 =< H3 ->
umerge3_1(T1, H1, T2, H2, [H1 | M], T3, H3);
umerge3_12(T1, H1, T2, H2, M, T3, H3, HdM) when H3 == HdM ->
umerge3_12_3(T1, H1, T2, H2, M, T3);
umerge3_12(T1, H1, T2, H2, M, T3, H3, _HdM) ->
umerge3_12_3(T1, H1, T2, H2, [H3 | M], T3).
% H1 =< H2, take L3 apart.
umerge3_12_3(T1, H1, T2, H2, M, [H3 | T3]) when H1 =< H3 ->
umerge3_1(T1, H1, T2, H2, [H1 | M], T3, H3);
umerge3_12_3(T1, H1, T2, H2, M, [H3 | T3]) ->
umerge3_12_3(T1, H1, T2, H2, [H3 | M], T3);
umerge3_12_3(T1, H1, T2, H2, M, []) ->
umerge2_1(T1, T2, [H1 | M], H1, H2).
% H1 > H2. Inlined.
umerge3_21(T1, H1, T2, H2, M, T3, H3, _HdM) when H2 =< H3 ->
umerge3_2(T1, H1, T2, H2, [H2 | M], T3, H3);
umerge3_21(T1, H1, T2, H2, M, T3, H3, HdM) when H3 == HdM ->
umerge3_21_3(T1, H1, T2, H2, M, T3);
umerge3_21(T1, H1, T2, H2, M, T3, H3, _HdM) ->
umerge3_21_3(T1, H1, T2, H2, [H3 | M], T3).
% H1 > H2, take L3 apart.
umerge3_21_3(T1, H1, T2, H2, M, [H3 | T3]) when H2 =< H3 ->
umerge3_2(T1, H1, T2, H2, [H2 | M], T3, H3);
umerge3_21_3(T1, H1, T2, H2, M, [H3 | T3]) ->
umerge3_21_3(T1, H1, T2, H2, [H3 | M], T3);
umerge3_21_3(T1, H1, T2, H2, M, []) ->
umerge2_2(T1, T2, [H2 | M], H1).
%% Take L1 apart.
rumerge3_1([H1 | T1], T2, H2, M, T3, H3) when H1 =< H2 ->
rumerge3_12a(T1, H1, T2, H2, M, T3, H3);
rumerge3_1([H1 | T1], T2, H2, M, T3, H3) when H1 =< H3 ->
rumerge3_21_3(T1, T2, H2, M, T3, H3, H1);
rumerge3_1([H1 | T1], T2, H2, M, T3, H3) ->
rumerge3_1(T1, T2, H2, [H1 | M], T3, H3);
rumerge3_1([], T2, H2, M, T3, H3) when H2 =< H3 ->
rumerge2_2(T2, T3, M, H3, H2);
rumerge3_1([], T2, H2, M, T3, H3) ->
rumerge2_1(T2, T3, [H2 | M], H3).
% H1 =< H2. Inlined.
rumerge3_12a(T1, H1, T2, H2, M, T3, H3) when H2 =< H3 ->
rumerge3_12_3(T1, T2, H2, M, T3, H3, H1);
rumerge3_12a(T1, H1, T2, H2, M, T3, H3) ->
rumerge3_2(T1, T2, H2, M, T3, H3, H1).
%% Take L2 apart. H2M > H3. H2M > H2.
rumerge3_2(T1, [H2 | T2], H2M, M, T3, H3, H1) when H1 =< H2 ->
% H2M > H1.
rumerge3_12b(T1, H1, T2, H2, M, T3, H3, H2M);
rumerge3_2(T1, [H2 | T2], H2M, M, T3, H3, H1) when H1 == H2M ->
rumerge3_1(T1, T2, H2, [H1 | M], T3, H3);
rumerge3_2(T1, [H2 | T2], H2M, M, T3, H3, H1) when H1 =< H3 ->
% H2M > H1.
rumerge3_21_3(T1, T2, H2, [H2M | M], T3, H3, H1);
rumerge3_2(T1, [H2 | T2], H2M, M, T3, H3, H1) ->
% H2M > H1.
rumerge3_1(T1, T2, H2, [H1, H2M | M], T3, H3);
rumerge3_2(T1, [], H2M, M, T3, H3, H1) when H1 == H2M ->
rumerge2_1(T1, T3, [H1 | M], H3);
rumerge3_2(T1, [], H2M, M, T3, H3, H1) when H1 =< H3 ->
rumerge2_2(T1, T3, [H2M | M], H3, H1);
rumerge3_2(T1, [], H2M, M, T3, H3, H1) ->
rumerge2_1(T1, T3, [H1, H2M | M], H3).
% H1 =< H2. Inlined.
rumerge3_12b(T1, H1, T2, H2, M, T3, H3, H2M) when H2 =< H3 ->
rumerge3_12_3(T1, T2, H2, [H2M | M], T3, H3, H1);
rumerge3_12b(T1, H1, T2, H2, M, T3, H3, H2M) ->
rumerge3_2(T1, T2, H2, [H2M | M], T3, H3, H1).
% H1 =< H2, take L3 apart.
rumerge3_12_3(T1, T2, H2, M, [H3 | T3], H3M, H1) when H2 =< H3 ->
rumerge3_12_3(T1, T2, H2, [H3M | M], T3, H3, H1);
rumerge3_12_3(T1, T2, H2, M, [H3 | T3], H3M, H1) when H2 == H3M ->
rumerge3_2(T1, T2, H2, M, T3, H3, H1);
rumerge3_12_3(T1, T2, H2, M, [H3 | T3], H3M, H1) ->
rumerge3_2(T1, T2, H2, [H3M | M], T3, H3, H1);
rumerge3_12_3(T1, T2, H2, M, [], H3M, H1) when H2 == H3M ->
rumerge2_2(T1, T2, M, H2, H1);
rumerge3_12_3(T1, T2, H2, M, [], H3M, H1) ->
rumerge2_2(T1, T2, [H3M | M], H2, H1).
% H1 > H2, take L3 apart.
rumerge3_21_3(T1, T2, H2, M, [H3 | T3], H3M, H1) when H1 =< H3 ->
rumerge3_21_3(T1, T2, H2, [H3M | M], T3, H3, H1);
rumerge3_21_3(T1, T2, H2, M, [H3 | T3], H3M, H1) when H1 == H3M ->
rumerge3_1(T1, T2, H2, [H1 | M], T3, H3);
rumerge3_21_3(T1, T2, H2, M, [H3 | T3], H3M, H1) ->
rumerge3_1(T1, T2, H2, [H1, H3M | M], T3, H3);
rumerge3_21_3(T1, T2, H2, M, [], H3M, H1) when H1 == H3M ->
rumerge2_1(T1, T2, [H1 | M], H2);
rumerge3_21_3(T1, T2, H2, M, [], H3M, H1) ->
rumerge2_1(T1, T2, [H1, H3M | M], H2).
%% umerge/2
%% Elements from the first list are kept and prioritized.
umerge2_1([H1 | T1], T2, M, _HdM, H2) when H1 =< H2 ->
umerge2_1(T1, T2, [H1 | M], H1, H2);
umerge2_1([H1 | T1], T2, M, HdM, H2) when H2 == HdM ->
umerge2_2(T1, T2, M, H1);
umerge2_1([H1 | T1], T2, M, _HdM, H2) ->
umerge2_2(T1, T2, [H2 | M], H1);
umerge2_1([], T2, M, HdM, H2) when H2 == HdM ->
lists:reverse(T2, M);
umerge2_1([], T2, M, _HdM, H2) ->
lists:reverse(T2, [H2 | M]).
umerge2_2(T1, [H2 | T2], M, H1) when H1 =< H2 ->
umerge2_1(T1, T2, [H1 | M], H1, H2);
umerge2_2(T1, [H2 | T2], M, H1) ->
umerge2_2(T1, T2, [H2 | M], H1);
umerge2_2(T1, [], M, H1) ->
lists:reverse(T1, [H1 | M]).
%% rumerge/2
%% Elements from the first list are kept and prioritized.
rumerge2_1([H1 | T1], T2, M, H2) when H1 =< H2 ->
rumerge2_2(T1, T2, M, H2, H1);
rumerge2_1([H1 | T1], T2, M, H2) ->
rumerge2_1(T1, T2, [H1 | M], H2);
rumerge2_1([], T2, M, H2) ->
lists:reverse(T2, [H2 | M]).
% H1 =< H2M.
rumerge2_2(T1, [H2 | T2], M, H2M, H1) when H1 =< H2 ->
rumerge2_2(T1, T2, [H2M | M], H2, H1);
rumerge2_2(T1, [H2 | T2], M, H2M, H1) when H1 == H2M ->
rumerge2_1(T1, T2, [H1 | M], H2);
rumerge2_2(T1, [H2 | T2], M, H2M, H1) ->
rumerge2_1(T1, T2, [H1, H2M | M], H2);
rumerge2_2(T1, [], M, H2M, H1) when H1 == H2M ->
lists:reverse(T1, [H1 | M]);
rumerge2_2(T1, [], M, H2M, H1) ->
lists:reverse(T1, [H1, H2M | M]).
%% keysort/2
%% Ascending.
keysplit_1(I, X, EX, Y, EY, [Z | L], R, Rs) ->
case element(I, Z) of
EZ when EY =< EZ ->
keysplit_1(I, Y, EY, Z, EZ, L, [X | R], Rs);
EZ when EX =< EZ ->
keysplit_1(I, Z, EZ, Y, EY, L, [X | R], Rs);
_EZ when R == [] ->
keysplit_1(I, X, EX, Y, EY, L, [Z], Rs);
EZ ->
keysplit_1_1(I, X, EX, Y, EY, EZ, R, Rs, Z, L)
end;
keysplit_1(I, X, _EX, Y, _EY, [], R, Rs) ->
rkeymergel(I, [[Y, X | R] | Rs], [], asc).
keysplit_1_1(I, X, EX, Y, EY, ES, R, Rs, S, [Z | L]) ->
case element(I, Z) of
EZ when EY =< EZ ->
keysplit_1_1(I, Y, EY, Z, EZ, ES, [X | R], Rs, S, L);
EZ when EX =< EZ ->
keysplit_1_1(I, Z, EZ, Y, EY, ES, [X | R], Rs, S, L);
EZ when ES =< EZ ->
keysplit_1(I, S, ES, Z, EZ, L, [], [[Y, X | R] | Rs]);
EZ ->
keysplit_1(I, Z, EZ, S, ES, L, [], [[Y, X | R] | Rs])
end;
keysplit_1_1(I, X, _EX, Y, _EY, _ES, R, Rs, S, []) ->
rkeymergel(I, [[S], [Y, X | R] | Rs], [], asc).
%% Descending.
keysplit_2(I, X, EX, Y, EY, [Z | L], R, Rs) ->
case element(I, Z) of
EZ when EY > EZ ->
keysplit_2(I, Y, EY, Z, EZ, L, [X | R], Rs);
EZ when EX > EZ ->
keysplit_2(I, Z, EZ, Y, EY, L, [X | R], Rs);
_EZ when R == [] ->
keysplit_2(I, X, EX, Y, EY, L, [Z], Rs);
EZ ->
keysplit_2_1(I, X, EX, Y, EY, EZ, R, Rs, Z, L)
end;
keysplit_2(I, X, _EX, Y, _EY, [], R, Rs) ->
keymergel(I, [[Y, X | R] | Rs], [], desc).
keysplit_2_1(I, X, EX, Y, EY, ES, R, Rs, S, [Z | L]) ->
case element(I, Z) of
EZ when EY > EZ ->
keysplit_2_1(I, Y, EY, Z, EZ, ES, [X | R], Rs, S, L);
EZ when EX > EZ ->
keysplit_2_1(I, Z, EZ, Y, EY, ES, [X | R], Rs, S, L);
EZ when ES > EZ ->
keysplit_2(I, S, ES, Z, EZ, L, [], [[Y, X | R] | Rs]);
EZ ->
keysplit_2(I, Z, EZ, S, ES, L, [], [[Y, X | R] | Rs])
end;
keysplit_2_1(I, X, _EX, Y, _EY, _ES, R, Rs, S, []) ->
keymergel(I, [[S], [Y, X | R] | Rs], [], desc).
keymergel(I, [T1, [H2 | T2], [H3 | T3] | L], Acc, O) when O == asc ->
M = keymerge3_1(I, T1, [],O,element(I,H2), H2, T2, element(I,H3), H3, T3),
keymergel(I, L, [M | Acc], O);
keymergel(I, [[H3 | T3], [H2 | T2], T1 | L], Acc, O) when O == desc ->
M = keymerge3_1(I, T1, [],O,element(I,H2), H2, T2, element(I,H3), H3, T3),
keymergel(I, L, [M | Acc], O);
keymergel(I, [T1, [H2 | T2] | L], Acc, asc) ->
keymergel(I, L, [keymerge2_1(I, T1, element(I,H2),H2,T2,[]) | Acc], asc);
keymergel(I, [[H2 | T2], T1 | L], Acc, desc) ->
keymergel(I, L, [keymerge2_1(I, T1, element(I,H2),H2,T2,[]) | Acc], desc);
keymergel(_I, [L], [], _O) ->
L;
keymergel(I, [L], Acc, O) ->
rkeymergel(I, [lists:reverse(L, []) | Acc], [], O);
keymergel(I, [], Acc, O) ->
rkeymergel(I, Acc, [], O).
rkeymergel(I, [[H3 | T3], [H2 | T2], T1 | L], Acc, O) when O == asc ->
M = rkeymerge3_1(I, T1, [],O,element(I,H2), H2, T2, element(I,H3), H3,T3),
rkeymergel(I, L, [M | Acc], O);
rkeymergel(I, [T1, [H2 | T2], [H3 | T3] | L], Acc, O) when O == desc ->
M = rkeymerge3_1(I, T1, [],O,element(I,H2), H2, T2, element(I,H3), H3,T3),
rkeymergel(I, L, [M | Acc], O);
rkeymergel(I, [[H2 | T2], T1 | L], Acc, asc) ->
rkeymergel(I, L, [rkeymerge2_1(I, T1, element(I,H2),H2,T2,[]) | Acc],asc);
rkeymergel(I, [T1, [H2 | T2] | L], Acc, desc) ->
rkeymergel(I, L, [rkeymerge2_1(I,T1, element(I,H2),H2,T2,[]) | Acc],desc);
rkeymergel(I, [L], Acc, O) ->
keymergel(I, [lists:reverse(L, []) | Acc], [], O);
rkeymergel(I, [], Acc, O) ->
keymergel(I, Acc, [], O).
%%% An extra argument, D, just to avoid some move instructions.
%% Take L1 apart.
keymerge3_1(I, [H1 | T1], M, D, E2, H2, T2, E3, H3, T3) ->
case element(I, H1) of
E1 when E1 =< E2 ->
keymerge3_12(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, D);
E1 ->
keymerge3_21(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, T2)
end;
keymerge3_1(I, [], M, _D, E2, H2, T2, E3, H3, T3) when E2 =< E3 ->
keymerge2_1(I, T2, E3, H3, T3, [H2 | M]);
keymerge3_1(I, [], M, _D, E2, H2, T2, _E3, H3, T3) ->
keymerge2_2(I, T2, E2, H3, T3, M, H2).
%% Take L2 apart.
keymerge3_2(I, E1, H1, T1, [H2 | T2], M, D, E3, H3, T3) ->
case element(I, H2) of
E2 when E1 =< E2 ->
keymerge3_12(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, T1);
E2 ->
keymerge3_21(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, D)
end;
keymerge3_2(I, E1, H1, T1, [], M, _D, E3, H3, T3) when E1 =< E3 ->
keymerge2_1(I, T1, E3, H3, T3, [H1 | M]);
keymerge3_2(I, E1, H1, T1, [], M, _D, _E3, H3, T3) ->
keymerge2_2(I, T1, E1, H3, T3, M, H1).
% E1 =< E2. Inlined.
keymerge3_12(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, D) when E1 =< E3 ->
keymerge3_1(I, T1, [H1 | M], D, E2, H2, T2, E3, H3, T3);
keymerge3_12(I, E1, H1, T1, E2, H2, T2, _E3, H3, T3, M, _D) ->
keymerge3_12_3(I, E1, H1, T1, E2, H2, T2, T3, [H3 | M]).
% E1 =< E2, take L3 apart.
keymerge3_12_3(I, E1, H1, T1, E2, H2, T2, [H3 | T3], M) ->
case element(I, H3) of
E3 when E1 =< E3 ->
keymerge3_1(I, T1, [H1 | M], T1, E2, H2, T2, E3, H3, T3);
_E3 ->
keymerge3_12_3(I, E1, H1, T1, E2, H2, T2, T3, [H3 | M])
end;
keymerge3_12_3(I, _E1, H1, T1, E2, H2, T2, [], M) ->
keymerge2_1(I, T1, E2, H2, T2, [H1 | M]).
% E1 > E2. Inlined.
keymerge3_21(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, D) when E2 =< E3 ->
keymerge3_2(I, E1, H1, T1, T2, [H2 | M], D, E3, H3, T3);
keymerge3_21(I, E1, H1, T1, E2, H2, T2, _E3, H3, T3, M, _D) ->
keymerge3_21_3(I, E1, H1, T1, E2, H2, T2, T3, [H3 | M]).
% E1 > E2, take L3 apart.
keymerge3_21_3(I, E1, H1, T1, E2, H2, T2, [H3 | T3], M) ->
case element(I, H3) of
E3 when E2 =< E3 ->
keymerge3_2(I, E1, H1, T1, T2, [H2 | M], T2, E3, H3, T3);
_E3 ->
keymerge3_21_3(I, E1, H1, T1, E2, H2, T2, T3, [H3 | M])
end;
keymerge3_21_3(I, E1, H1, T1, _E2, H2, T2, [], M) ->
keymerge2_2(I, T1, E1, H2, T2, M, H1).
%% Take L1 apart.
rkeymerge3_1(I, [H1 | T1], M, D, E2, H2, T2, E3, H3, T3) ->
case element(I, H1) of
E1 when E1 =< E2 ->
rkeymerge3_12(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, T2);
E1 ->
rkeymerge3_21(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, D)
end;
rkeymerge3_1(I, [], M, _D, E2, H2, T2, E3, H3, T3) when E2 =< E3 ->
rkeymerge2_2(I, E2, T2, H3, T3, M, H2);
rkeymerge3_1(I, [], M, _D, _E2, H2, T2, E3, H3, T3) ->
rkeymerge2_1(I, T2, E3, H3, T3, [H2 | M]).
%% Take L2 apart.
rkeymerge3_2(I, E1, H1, T1, [H2 | T2], M, D, E3, H3, T3) ->
case element(I, H2) of
E2 when E1 =< E2 ->
rkeymerge3_12(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, D);
E2 ->
rkeymerge3_21(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, T1)
end;
rkeymerge3_2(I, E1, H1, T1, [], M, _D, E3, H3, T3) when E1 =< E3 ->
rkeymerge2_2(I, E1, T1, H3, T3, M, H1);
rkeymerge3_2(I, _E1, H1, T1, [], M, _D, E3, H3, T3) ->
rkeymerge2_1(I, T1, E3, H3, T3, [H1 | M]).
% E1 =< E2. Inlined.
rkeymerge3_12(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, _D) when E2 =< E3 ->
rkeymerge3_12_3(I, E1, H1, T1, E2, H2, T2, T3, [H3 | M]);
rkeymerge3_12(I, E1, H1, T1, _E2, H2, T2, E3, H3, T3, M, D) ->
rkeymerge3_2(I, E1, H1, T1, T2, [H2 | M], D, E3, H3, T3).
% E1 =< E2, take L3 apart.
rkeymerge3_12_3(I, E1, H1, T1, E2, H2, T2, [H3 | T3], M) ->
case element(I, H3) of
E3 when E2 =< E3 ->
rkeymerge3_12_3(I, E1, H1, T1, E2, H2, T2, T3, [H3 | M]);
E3 ->
rkeymerge3_2(I, E1, H1, T1, T2, [H2 | M], T2, E3, H3, T3)
end;
rkeymerge3_12_3(I, E1, H1, T1, _E2, H2, T2, [], M) ->
rkeymerge2_2(I, E1, T1, H2, T2, M, H1).
% E1 > E2. Inlined.
rkeymerge3_21(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, _D) when E1 =< E3 ->
rkeymerge3_21_3(I, E1, H1, T1, E2, H2, T2, T3, [H3 | M]);
rkeymerge3_21(I, _E1, H1, T1, E2, H2, T2, E3, H3, T3, M, D) ->
rkeymerge3_1(I, T1, [H1 | M], D, E2, H2, T2, E3, H3, T3).
% E1 > E2, take L3 apart.
rkeymerge3_21_3(I, E1, H1, T1, E2, H2, T2, [H3 | T3], M) ->
case element(I, H3) of
E3 when E1 =< E3 ->
rkeymerge3_21_3(I, E1, H1, T1, E2, H2, T2, T3, [H3 | M]);
E3 ->
rkeymerge3_1(I, T1, [H1 | M], T1, E2, H2, T2, E3, H3, T3)
end;
rkeymerge3_21_3(I, _E1, H1, T1, E2, H2, T2, [], M) ->
rkeymerge2_1(I, T1, E2, H2, T2, [H1 | M]).
%% keymerge/3
%% Elements from the first list are prioritized.
keymerge2_1(I, [H1 | T1], E2, H2, T2, M) ->
case element(I, H1) of
E1 when E1 =< E2 ->
keymerge2_1(I, T1, E2, H2, T2, [H1 | M]);
E1 ->
keymerge2_2(I, T1, E1, H2, T2, M, H1)
end;
keymerge2_1(_I, [], _E2, H2, T2, M) ->
lists:reverse(T2, [H2 | M]).
keymerge2_2(I, T1, E1, HdM, [H2 | T2], M, H1) ->
case element(I, H2) of
E2 when E1 =< E2 ->
keymerge2_1(I, T1, E2, H2, T2, [H1, HdM | M]);
_E2 ->
keymerge2_2(I, T1, E1, H2, T2, [HdM | M], H1)
end;
keymerge2_2(_I, T1, _E1, HdM, [], M, H1) ->
lists:reverse(T1, [H1, HdM | M]).
%% rkeymerge/3
rkeymerge2_1(I, [H1 | T1], E2, H2, T2, M) ->
case element(I, H1) of
E1 when E1 =< E2 ->
rkeymerge2_2(I, E1, T1, H2, T2, M, H1);
_E1 ->
rkeymerge2_1(I, T1, E2, H2, T2, [H1 | M])
end;
rkeymerge2_1(_I, [], _E2, H2, T2, M) ->
lists:reverse(T2, [H2 | M]).
rkeymerge2_2(I, E1, T1, HdM, [H2 | T2], M, H1) ->
case element(I, H2) of
E2 when E1 =< E2 ->
rkeymerge2_2(I, E1, T1, H2, T2, [HdM | M], H1);
E2 ->
rkeymerge2_1(I, T1, E2, H2, T2, [H1, HdM | M])
end;
rkeymerge2_2(_I, _E1, T1, HdM, [], M, H1) ->
lists:reverse(T1, [H1, HdM | M]).
%% ukeysort/2
%% Ascending.
ukeysplit_1(I, X, EX, Y, EY, [Z | L], R, Rs) ->
case element(I, Z) of
EZ when EY == EZ ->
ukeysplit_1(I, X, EX, Y, EY, L, R, Rs);
EZ when EY < EZ ->
ukeysplit_1(I, Y, EY, Z, EZ, L, [X | R], Rs);
EZ when EX == EZ ->
ukeysplit_1(I, X, EX, Y, EY, L, R, Rs);
EZ when EX < EZ ->
ukeysplit_1(I, Z, EZ, Y, EY, L, [X | R], Rs);
_EZ when R == [] ->
ukeysplit_1(I, X, EX, Y, EY, L, [Z], Rs);
EZ ->
ukeysplit_1_1(I, X, EX, Y, EY, L, R, Rs, Z, EZ)
end;
ukeysplit_1(I, X, _EX, Y, _EY, [], R, Rs) ->
rukeymergel(I, [[Y, X | R] | Rs], []).
ukeysplit_1_1(I, X, EX, Y, EY, [Z | L], R, Rs, S, ES) ->
case element(I, Z) of
EZ when EY == EZ ->
ukeysplit_1_1(I, X, EX, Y, EY, L, R, Rs, S, ES);
EZ when EY < EZ ->
ukeysplit_1_1(I, Y, EY, Z, EZ, L, [X | R], Rs, S, ES);
EZ when EX == EZ ->
ukeysplit_1_1(I, X, EX, Y, EY, L, R, Rs, S, ES);
EZ when EX < EZ ->
ukeysplit_1_1(I, Z, EZ, Y, EY, L, [X | R], Rs, S, ES);
EZ when ES == EZ ->
ukeysplit_1_1(I, X, EX, Y, EY, L, R, Rs, S, ES);
EZ when ES < EZ ->
ukeysplit_1(I, S, ES, Z, EZ, L, [], [[Y, X | R] | Rs]);
EZ ->
ukeysplit_1(I, Z, EZ, S, ES, L, [], [[Y, X | R] | Rs])
end;
ukeysplit_1_1(I, X, _EX, Y, _EY, [], R, Rs, S, _ES) ->
rukeymergel(I, [[S], [Y, X | R] | Rs], []).
%% Descending.
ukeysplit_2(I, Y, EY, [Z | L], R) ->
case element(I, Z) of
EZ when EY == EZ ->
ukeysplit_2(I, Y, EY, L, R);
EZ when EY < EZ ->
ukeysplit_1(I, Y, EY, Z, EZ, L, [], [lists:reverse(R, [])]);
EZ ->
ukeysplit_2(I, Z, EZ, L, [Y | R])
end;
ukeysplit_2(_I, Y, _EY, [], R) ->
[Y | R].
ukeymergel(I, [T1, [H2 | T2], [H3 | T3] | L], Acc) ->
%% The fourth argument, [H2 | H3] (=HdM), may confuse type
%% checkers. Its purpose is to ensure that the tests H2 == HdM
%% and H3 == HdM in ukeymerge3_1 will always fail as long as M == [].
M = ukeymerge3_1(I, T1, Acc, [H2 | H3], element(I, H2), H2, T2, [],
element(I, H3), H3, T3),
ukeymergel(I, L, [M | Acc]);
ukeymergel(I, [[H1 | T1], T2 | L], Acc) ->
ukeymergel(I, L, [ukeymerge2_2(I, T1, element(I, H1), H1, T2, []) | Acc]);
ukeymergel(_I, [L], []) ->
L;
ukeymergel(I, [L], Acc) ->
rukeymergel(I, [lists:reverse(L, []) | Acc], []);
ukeymergel(I, [], Acc) ->
rukeymergel(I, Acc, []).
rukeymergel(I, [[H3 | T3], [H2 | T2], T1 | L], Acc) ->
M = rukeymerge3_1(I, T1, Acc, [], element(I, H2), H2, T2, [],
element(I, H3), H3, T3),
rukeymergel(I, L, [M | Acc]);
rukeymergel(I, [[H2 | T2], T1 | L], Acc) ->
rukeymergel(I, L, [rukeymerge2_1(I, T1, element(I,H2), T2, [], H2)|Acc]);
rukeymergel(I, [L], Acc) ->
ukeymergel(I, [lists:reverse(L, []) | Acc], []);
rukeymergel(I, [], Acc) ->
ukeymergel(I, Acc, []).
%%% An extra argument, D, just to avoid some move instructions.
%% Take L1 apart.
ukeymerge3_1(I, [H1 | T1], D, HdM, E2, H2, T2, M, E3, H3, T3) ->
case element(I, H1) of
E1 when E1 =< E2 ->
ukeymerge3_12(I, E1, T1, H1, E2, H2, T2, E3, H3, T3, M, HdM, D);
E1 when E2 == HdM ->
ukeymerge3_2(I, E1, T1, H1, T2, HdM, T2, M, E3, H3, T3);
E1 ->
ukeymerge3_21(I, E1, T1, H1, E2, H2, T2, E3, H3, T3, M, HdM, T2)
end;
ukeymerge3_1(I, [], _D, HdM, E2, _H2, T2, M, E3, H3, T3) when E2 == HdM ->
ukeymerge2_1(I, T2, E3, HdM, T3, M, H3);
ukeymerge3_1(I, [], _D, _HdM, E2, H2, T2, M, E3, H3, T3) when E2 =< E3 ->
ukeymerge2_1(I, T2, E3, E2, T3, [H2 | M], H3);
ukeymerge3_1(I, [], _D, HdM, E2, H2, T2, M, E3, _H3, T3) when E3 == HdM ->
ukeymerge2_2(I, T2, E2, H2, T3, M);
ukeymerge3_1(I, [], _D, _HdM, E2, H2, T2, M, _E3, H3, T3) ->
ukeymerge2_2(I, T2, E2, H2, T3, [H3 | M]).
%% Take L2 apart.
ukeymerge3_2(I, E1, T1, H1, [H2 | T2], HdM, D, M, E3, H3, T3) ->
case element(I, H2) of
E2 when E1 =< E2 ->
ukeymerge3_12(I, E1, T1, H1, E2, H2, T2, E3, H3, T3, M, HdM, T1);
E2 ->
ukeymerge3_21(I, E1, T1, H1, E2, H2, T2, E3, H3, T3, M, HdM, D)
end;
ukeymerge3_2(I, E1, T1, H1, [], _HdM, _D, M, E3, H3, T3) when E1 =< E3 ->
ukeymerge2_1(I, T1, E3, E1, T3, [H1 | M], H3);
ukeymerge3_2(I, E1, T1, H1, [], HdM, _D, M, E3, _H3, T3) when E3 == HdM ->
ukeymerge2_2(I, T1, E1, H1, T3, M);
ukeymerge3_2(I, E1, T1, H1, [], _HdM, _D, M, _E3, H3, T3) ->
ukeymerge2_2(I, T1, E1, H1, T3, [H3 | M]).
% E1 =< E2. Inlined.
ukeymerge3_12(I, E1, T1, H1, E2, H2, T2, E3, H3, T3, M, _HdM, D)
when E1 =< E3 ->
ukeymerge3_1(I, T1, D, E1, E2, H2, T2, [H1 | M], E3, H3, T3);
ukeymerge3_12(I, E1, T1, H1, E2, H2, T2, E3, _H3, T3, M, HdM, _D)
when E3 == HdM ->
ukeymerge3_12_3(I, E1, T1, H1, E2, H2, T2, M, T3);
ukeymerge3_12(I, E1, T1, H1, E2, H2, T2, _E3, H3, T3, M, _HdM, _D) ->
ukeymerge3_12_3(I, E1, T1, H1, E2, H2, T2, [H3 | M], T3).
% E1 =< E2, take L3 apart.
ukeymerge3_12_3(I, E1, T1, H1, E2, H2, T2, M, [H3 | T3]) ->
case element(I, H3) of
E3 when E1 =< E3 ->
ukeymerge3_1(I, T1, T1, E1, E2, H2, T2, [H1 | M], E3, H3, T3);
_E3 ->
ukeymerge3_12_3(I, E1, T1, H1, E2, H2, T2, [H3 | M], T3)
end;
ukeymerge3_12_3(I, E1, T1, H1, E2, H2, T2, M, []) ->
ukeymerge2_1(I, T1, E2, E1, T2, [H1 | M], H2).
% E1 > E2. Inlined.
ukeymerge3_21(I, E1, T1, H1, E2, H2, T2, E3, H3, T3, M, _HdM, D)
when E2 =< E3 ->
ukeymerge3_2(I, E1, T1, H1, T2, E2, D, [H2 | M], E3, H3, T3);
ukeymerge3_21(I, E1, T1, H1, E2, H2, T2, E3, _H3, T3, M, HdM, _D)
when E3 == HdM ->
ukeymerge3_21_3(I, E1, T1, H1, E2, H2, T2, M, T3);
ukeymerge3_21(I, E1, T1, H1, E2, H2, T2, _E3, H3, T3, M, _HdM, _D) ->
ukeymerge3_21_3(I, E1, T1, H1, E2, H2, T2, [H3 | M], T3).
% E1 > E2, take L3 apart.
ukeymerge3_21_3(I, E1, T1, H1, E2, H2, T2, M, [H3 | T3]) ->
case element(I, H3) of
E3 when E2 =< E3 ->
ukeymerge3_2(I, E1, T1, H1, T2, E2, T2, [H2 | M], E3, H3, T3);
_E3 ->
ukeymerge3_21_3(I, E1, T1, H1, E2, H2, T2, [H3 | M], T3)
end;
ukeymerge3_21_3(I, E1, T1, H1, _E2, H2, T2, M, []) ->
ukeymerge2_2(I, T1, E1, H1, T2, [H2 | M]).
%%% Two extra arguments, D1 and D2, just to avoid some move instructions.
%% Take L1 apart.
rukeymerge3_1(I, [H1 | T1], D1, D2, E2, H2, T2, M, E3, H3, T3) ->
case element(I, H1) of
E1 when E1 =< E2 ->
rukeymerge3_12a(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M);
E1 ->
rukeymerge3_21a(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, D1, D2)
end;
rukeymerge3_1(I, [], _D1, _D2, E2, H2, T2, M, E3, H3, T3) when E2 =< E3 ->
rukeymerge2_2(I, T2, E2, T3, M, E3, H3, H2);
rukeymerge3_1(I, [], _D1, _D2, _E2, H2, T2, M, E3, H3, T3) ->
rukeymerge2_1(I, T2, E3, T3, [H2 | M], H3).
% E1 =< E2. Inlined.
rukeymerge3_12a(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M) when E2 =< E3 ->
rukeymerge3_12_3(I, E1, H1, T1, E2, H2, T2, M, E3, H3, T3);
rukeymerge3_12a(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M) ->
rukeymerge3_2(I, E1, H1, T1, T2, H2, E2, M, E3, H3, T3).
% E1 > E2. Inlined
rukeymerge3_21a(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, _D1, _D2)
when E1 =< E3 ->
rukeymerge3_21_3(I, E1, H1, T1, E2, H2, T2, M, E3, H3, T3);
rukeymerge3_21a(I, _E1, H1, T1, E2, H2, T2, E3, H3, T3, M, D1, D2) ->
rukeymerge3_1(I, T1, D1, D2, E2, H2, T2, [H1 | M], E3, H3, T3).
%% Take L2 apart. E2M > E3. E2M > E2.
rukeymerge3_2(I, E1, H1, T1, [H2 | T2], H2M, E2M, M, E3, H3, T3) ->
case element(I, H2) of
E2 when E1 =< E2 ->
% E2M > E1.
rukeymerge3_12b(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, H2M);
E2 when E1 == E2M ->
rukeymerge3_1(I, T1, H1, T1, E2, H2, T2, [H1 | M], E3, H3, T3);
E2 ->
% E2M > E1.
rukeymerge3_21b(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, H2M)
end;
rukeymerge3_2(I, E1, H1, T1, [], _H2M, E2M, M, E3, H3, T3) when E1 == E2M ->
rukeymerge2_1(I, T1, E3, T3, [H1 | M], H3);
rukeymerge3_2(I, E1, H1, T1, [], H2M, _E2M, M, E3, H3, T3) when E1 =< E3 ->
rukeymerge2_2(I, T1, E1, T3, [H2M | M], E3, H3, H1);
rukeymerge3_2(I, _E1, H1, T1, [], H2M, _E2M, M, E3, H3, T3) ->
rukeymerge2_1(I, T1, E3, T3, [H1, H2M | M], H3).
% E1 =< E2. Inlined.
rukeymerge3_12b(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, H2M)
when E2 =< E3 ->
rukeymerge3_12_3(I, E1, H1, T1, E2, H2, T2, [H2M | M], E3, H3, T3);
rukeymerge3_12b(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M, H2M) ->
rukeymerge3_2(I, E1, H1, T1, T2, H2, E2, [H2M | M], E3, H3, T3).
% E1 > E2. Inlined
rukeymerge3_21b(I, E1, H1, T1, E2, H2, T2, E3, H3, T3, M,H2M) when E1 =< E3 ->
rukeymerge3_21_3(I, E1, H1, T1, E2, H2, T2, [H2M | M], E3, H3, T3);
rukeymerge3_21b(I, _E1, H1, T1, E2, H2, T2, E3, H3, T3, M, H2M) ->
rukeymerge3_1(I, T1, H1, T1, E2, H2, T2, [H1, H2M | M], E3, H3, T3).
% E1 =< E2, take L3 apart.
rukeymerge3_12_3(I, E1, H1, T1, E2, H2, T2, M, E3M, H3M, [H3 | T3]) ->
case element(I, H3) of
E3 when E2 =< E3 ->
rukeymerge3_12_3(I, E1, H1, T1, E2, H2, T2, [H3M | M], E3, H3, T3);
E3 when E2 == E3M ->
rukeymerge3_2(I, E1, H1, T1, T2, H2, E2, M, E3, H3, T3);
E3 ->
rukeymerge3_2(I, E1, H1, T1, T2, H2, E2, [H3M | M], E3, H3, T3)
end;
rukeymerge3_12_3(I, E1, H1, T1, E2, H2, T2, M, E3M, _H3M, []) when E2 == E3M ->
rukeymerge2_2(I, T1, E1, T2, M, E2, H2, H1);
rukeymerge3_12_3(I, E1, H1, T1, E2, H2, T2, M, _E3M, H3M, []) ->
rukeymerge2_2(I, T1, E1, T2, [H3M | M], E2, H2, H1).
% E1 > E2, take L3 apart.
rukeymerge3_21_3(I, E1, H1, T1, E2, H2, T2, M, E3M, H3M, [H3 | T3]) ->
case element(I, H3) of
E3 when E1 =< E3 ->
rukeymerge3_21_3(I, E1, H1, T1, E2, H2, T2, [H3M | M], E3, H3, T3);
E3 when E1 == E3M ->
rukeymerge3_1(I, T1, H1, T1, E2, H2, T2, [H1 | M], E3, H3, T3);
E3 ->
rukeymerge3_1(I, T1, H1, T1, E2, H2, T2, [H1,H3M | M], E3, H3, T3)
end;
rukeymerge3_21_3(I, E1, H1, T1, E2, H2, T2, M, E3M, _H3M, []) when E1 == E3M ->
rukeymerge2_1(I, T1, E2, T2, [H1 | M], H2);
rukeymerge3_21_3(I, _E1, H1, T1, E2, H2, T2, M, _E3M, H3M, []) ->
rukeymerge2_1(I, T1, E2, T2, [H1, H3M | M], H2).
%% ukeymerge/3
%% Elements from the first list are kept and prioritized.
ukeymerge2_1(I, [H1 | T1], E2, HdM, T2, M, H2) ->
case element(I, H1) of
E1 when E1 =< E2 ->
ukeymerge2_1(I, T1, E2, E1, T2, [H1 | M], H2);
E1 when E2 == HdM ->
ukeymerge2_2(I, T1, E1, H1, T2, M);
E1 ->
ukeymerge2_2(I, T1, E1, H1, T2, [H2 | M])
end;
ukeymerge2_1(_I, [], E2, HdM, T2, M, _H2) when E2 == HdM ->
lists:reverse(T2, M);
ukeymerge2_1(_I, [], _E2, _HdM, T2, M, H2) ->
lists:reverse(T2, [H2 | M]).
ukeymerge2_2(I, T1, E1, H1, [H2 | T2], M) ->
case element(I, H2) of
E2 when E1 =< E2 ->
ukeymerge2_1(I, T1, E2, E1, T2, [H1 | M], H2);
_E2 ->
ukeymerge2_2(I, T1, E1, H1, T2, [H2 | M])
end;
ukeymerge2_2(_I, T1, _E1, H1, [], M) ->
lists:reverse(T1, [H1 | M]).
%% rukeymerge/3
rukeymerge2_1(I, [H1 | T1], E2, T2, M, H2) ->
case element(I, H1) of
E1 when E1 =< E2 ->
rukeymerge2_2(I, T1, E1, T2, M, E2, H2, H1);
_E1 ->
rukeymerge2_1(I, T1, E2, T2, [H1 | M], H2)
end;
rukeymerge2_1(_I, [], _E2, T2, M, H2) ->
lists:reverse(T2, [H2 | M]).
rukeymerge2_2(I, T1, E1, [H2 | T2], M, E2M, H2M, H1) ->
case element(I, H2) of
E2 when E1 =< E2 ->
rukeymerge2_2(I, T1, E1, T2, [H2M | M], E2, H2, H1);
E2 when E1 == E2M ->
rukeymerge2_1(I, T1, E2, T2, [H1 | M], H2);
E2 ->
rukeymerge2_1(I, T1, E2, T2, [H1, H2M | M], H2)
end;
rukeymerge2_2(_I, T1, E1, [], M, E2M, _H2M, H1) when E1 == E2M ->
lists:reverse(T1, [H1 | M]);
rukeymerge2_2(_I, T1, _E1, [], M, _E2M, H2M, H1) ->
lists:reverse(T1, [H1, H2M | M]).
%% sort/2
%% Ascending.
fsplit_1(Y, X, Fun, [Z | L], R, Rs) ->
case Fun(Y, Z) of
true ->
fsplit_1(Z, Y, Fun, L, [X | R], Rs);
false ->
case Fun(X, Z) of
true ->
fsplit_1(Y, Z, Fun, L, [X | R], Rs);
false when R == [] ->
fsplit_1(Y, X, Fun, L, [Z], Rs);
false ->
fsplit_1_1(Y, X, Fun, L, R, Rs, Z)
end
end;
fsplit_1(Y, X, Fun, [], R, Rs) ->
rfmergel([[Y, X | R] | Rs], [], Fun, asc).
fsplit_1_1(Y, X, Fun, [Z | L], R, Rs, S) ->
case Fun(Y, Z) of
true ->
fsplit_1_1(Z, Y, Fun, L, [X | R], Rs, S);
false ->
case Fun(X, Z) of
true ->
fsplit_1_1(Y, Z, Fun, L, [X | R], Rs, S);
false ->
case Fun(S, Z) of
true ->
fsplit_1(Z, S, Fun, L, [], [[Y, X | R] | Rs]);
false ->
fsplit_1(S, Z, Fun, L, [], [[Y, X | R] | Rs])
end
end
end;
fsplit_1_1(Y, X, Fun, [], R, Rs, S) ->
rfmergel([[S], [Y, X | R] | Rs], [], Fun, asc).
%% Descending.
fsplit_2(Y, X, Fun, [Z | L], R, Rs) ->
case Fun(Y, Z) of
false ->
fsplit_2(Z, Y, Fun, L, [X | R], Rs);
true ->
case Fun(X, Z) of
false ->
fsplit_2(Y, Z, Fun, L, [X | R], Rs);
true when R == [] ->
fsplit_2(Y, X, Fun, L, [Z], Rs);
true ->
fsplit_2_1(Y, X, Fun, L, R, Rs, Z)
end
end;
fsplit_2(Y, X, Fun, [], R, Rs) ->
fmergel([[Y, X | R] | Rs], [], Fun, desc).
fsplit_2_1(Y, X, Fun, [Z | L], R, Rs, S) ->
case Fun(Y, Z) of
false ->
fsplit_2_1(Z, Y, Fun, L, [X | R], Rs, S);
true ->
case Fun(X, Z) of
false ->
fsplit_2_1(Y, Z, Fun, L, [X | R], Rs, S);
true ->
case Fun(S, Z) of
false ->
fsplit_2(Z, S, Fun, L, [], [[Y, X | R] | Rs]);
true ->
fsplit_2(S, Z, Fun, L, [], [[Y, X | R] | Rs])
end
end
end;
fsplit_2_1(Y, X, Fun, [], R, Rs, S) ->
fmergel([[S], [Y, X | R] | Rs], [], Fun, desc).
fmergel([T1, [H2 | T2] | L], Acc, Fun, asc) ->
fmergel(L, [fmerge2_1(T1, H2, Fun, T2, []) | Acc], Fun, asc);
fmergel([[H2 | T2], T1 | L], Acc, Fun, desc) ->
fmergel(L, [fmerge2_1(T1, H2, Fun, T2, []) | Acc], Fun, desc);
fmergel([L], [], _Fun, _O) ->
L;
fmergel([L], Acc, Fun, O) ->
rfmergel([lists:reverse(L, []) | Acc], [], Fun, O);
fmergel([], Acc, Fun, O) ->
rfmergel(Acc, [], Fun, O).
rfmergel([[H2 | T2], T1 | L], Acc, Fun, asc) ->
rfmergel(L, [rfmerge2_1(T1, H2, Fun, T2, []) | Acc], Fun, asc);
rfmergel([T1, [H2 | T2] | L], Acc, Fun, desc) ->
rfmergel(L, [rfmerge2_1(T1, H2, Fun, T2, []) | Acc], Fun, desc);
rfmergel([L], Acc, Fun, O) ->
fmergel([lists:reverse(L, []) | Acc], [], Fun, O);
rfmergel([], Acc, Fun, O) ->
fmergel(Acc, [], Fun, O).
%% merge/3
%% Elements from the first list are prioritized.
fmerge2_1([H1 | T1], H2, Fun, T2, M) ->
case Fun(H1, H2) of
true ->
fmerge2_1(T1, H2, Fun, T2, [H1 | M]);
false ->
fmerge2_2(H1, T1, Fun, T2, [H2 | M])
end;
fmerge2_1([], H2, _Fun, T2, M) ->
lists:reverse(T2, [H2 | M]).
fmerge2_2(H1, T1, Fun, [H2 | T2], M) ->
case Fun(H1, H2) of
true ->
fmerge2_1(T1, H2, Fun, T2, [H1 | M]);
false ->
fmerge2_2(H1, T1, Fun, T2, [H2 | M])
end;
fmerge2_2(H1, T1, _Fun, [], M) ->
lists:reverse(T1, [H1 | M]).
%% rmerge/3
rfmerge2_1([H1 | T1], H2, Fun, T2, M) ->
case Fun(H1, H2) of
true ->
rfmerge2_2(H1, T1, Fun, T2, [H2 | M]);
false ->
rfmerge2_1(T1, H2, Fun, T2, [H1 | M])
end;
rfmerge2_1([], H2, _Fun, T2, M) ->
lists:reverse(T2, [H2 | M]).
rfmerge2_2(H1, T1, Fun, [H2 | T2], M) ->
case Fun(H1, H2) of
true ->
rfmerge2_2(H1, T1, Fun, T2, [H2 | M]);
false ->
rfmerge2_1(T1, H2, Fun, T2, [H1 | M])
end;
rfmerge2_2(H1, T1, _Fun, [], M) ->
lists:reverse(T1, [H1 | M]).
%% usort/2
%% Ascending. X < Y
ufsplit_1(Y, X, Fun, [Z | L], R, Rs) ->
case Fun(Y, Z) of
true ->
case Fun(Z, Y) of
true -> % Z equal to Y
ufsplit_1(Y, X, Fun, L, R, Rs);
false ->
ufsplit_1(Z, Y, Fun, L, [X | R], Rs)
end;
false ->
case Fun(X, Z) of
true ->
case Fun(Z, X) of
true -> % Z equal to X
ufsplit_1(Y, X, Fun, L, R, Rs);
false ->
ufsplit_1(Y, Z, Fun, L, [X | R], Rs)
end;
false when R == [] ->
ufsplit_1(Y, X, Fun, L, [Z], Rs);
false ->
ufsplit_1_1(Y, X, Fun, L, R, Rs, Z)
end
end;
ufsplit_1(Y, X, Fun, [], R, Rs) ->
rufmergel([[Y, X | R] | Rs], [], Fun).
%% X < Y
ufsplit_1_1(Y, X, Fun, [Z | L], R, Rs, S) ->
case Fun(Y, Z) of
true ->
case Fun(Z, Y) of
true -> % Z equal to Y
ufsplit_1_1(Y, X, Fun, L, R, Rs, S);
false ->
ufsplit_1_1(Z, Y, Fun, L, [X | R], Rs, S)
end;
false ->
case Fun(X, Z) of
true ->
case Fun(Z, X) of
true -> % Z equal to X
ufsplit_1_1(Y, X, Fun, L, R, Rs, S);
false ->
ufsplit_1_1(Y, Z, Fun, L, [X | R], Rs, S)
end;
false ->
case Fun(S, Z) of
true ->
case Fun(Z, S) of
true -> % Z equal to S
ufsplit_1_1(Y, X, Fun, L, R, Rs, S);
false ->
ufsplit_1(Z, S, Fun, L, [], [[Y, X | R] | Rs])
end;
false ->
ufsplit_1(S, Z, Fun, L, [], [[Y, X | R] | Rs])
end
end
end;
ufsplit_1_1(Y, X, Fun, [], R, Rs, S) ->
rufmergel([[S], [Y, X | R] | Rs], [], Fun).
%% Descending.
ufsplit_2(Y, [Z | L], Fun, R) ->
case Fun(Y, Z) of
true ->
case Fun(Z, Y) of
true -> % Z equal to Y
ufsplit_2(Y, L, Fun, R);
false ->
ufsplit_1(Z, Y, Fun, L, [], [lists:reverse(R, [])])
end;
false ->
ufsplit_2(Z, L, Fun, [Y | R])
end;
ufsplit_2(Y, [], _Fun, R) ->
[Y | R].
ufmergel([[H1 | T1], T2 | L], Acc, Fun) ->
ufmergel(L, [ufmerge2_2(H1, T1, Fun, T2, []) | Acc], Fun);
ufmergel([L], [], _Fun) ->
L;
ufmergel([L], Acc, Fun) ->
rufmergel([lists:reverse(L, []) | Acc], [], Fun);
ufmergel([], Acc, Fun) ->
rufmergel(Acc, [], Fun).
rufmergel([[H2 | T2], T1 | L], Acc, Fun) ->
rufmergel(L, [rufmerge2_1(T1, H2, Fun, T2, []) | Acc], Fun);
rufmergel([L], Acc, Fun) ->
ufmergel([lists:reverse(L, []) | Acc], [], Fun);
rufmergel([], Acc, Fun) ->
ufmergel(Acc, [], Fun).
%% umerge/3
%% Elements from the first list are kept and prioritized.
%% HdM before H2.
ufmerge2_1([H1 | T1], H2, Fun, T2, M, HdM) ->
case Fun(H1, H2) of
true ->
ufmerge2_1(T1, H2, Fun, T2, [H1 | M], H1);
false ->
case Fun(H2, HdM) of
true -> % HdM equal to H2
ufmerge2_2(H1, T1, Fun, T2, M);
false ->
ufmerge2_2(H1, T1, Fun, T2, [H2 | M])
end
end;
ufmerge2_1([], H2, Fun, T2, M, HdM) ->
case Fun(H2, HdM) of
true -> % HdM equal to H2
lists:reverse(T2, M);
false ->
lists:reverse(T2, [H2 | M])
end.
ufmerge2_2(H1, T1, Fun, [H2 | T2], M) ->
case Fun(H1, H2) of
true ->
ufmerge2_1(T1, H2, Fun, T2, [H1 | M], H1);
false ->
ufmerge2_2(H1, T1, Fun, T2, [H2 | M])
end;
ufmerge2_2(H1, T1, _Fun, [], M) ->
lists:reverse(T1, [H1 | M]).
%% rumerge/3
rufmerge2_1([H1 | T1], H2, Fun, T2, M) ->
case Fun(H1, H2) of
true ->
rufmerge2_2(H1, T1, Fun, T2, M, H2);
false ->
rufmerge2_1(T1, H2, Fun, T2, [H1 | M])
end;
rufmerge2_1([], H2, _Fun, T2, M) ->
lists:reverse(T2, [H2 | M]).
%% H1 before H2M
rufmerge2_2(H1, T1, Fun, [H2 | T2], M, H2M) ->
case Fun(H1, H2) of
true ->
rufmerge2_2(H1, T1, Fun, T2, [H2M | M], H2);
false ->
case Fun(H2M, H1) of
true -> % H2M equal to H1
rufmerge2_1(T1, H2, Fun, T2, [H1 | M]);
false ->
rufmerge2_1(T1, H2, Fun, T2, [H1, H2M | M])
end
end;
rufmerge2_2(H1, T1, Fun, [], M, H2M) ->
case Fun(H2M, H1) of
true ->
lists:reverse(T1, [H1 | M]);
false ->
lists:reverse(T1, [H1, H2M | M])
end.
