%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2007-2014. 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%
%%
%% @author Richard Carlsson <[email protected]>
%% @author Dan Gudmundsson <[email protected]>
%% @version 1.0
%% @doc Functional, extendible arrays. Arrays can have fixed size, or
%% can grow automatically as needed. A default value is used for entries
%% that have not been explicitly set.
%%
%% Arrays uses <b>zero</b> based indexing. This is a deliberate design
%% choice and differs from other erlang datastructures, e.g. tuples.
%%
%% Unless specified by the user when the array is created, the default
%% value is the atom `undefined'. There is no difference between an
%% unset entry and an entry which has been explicitly set to the same
%% value as the default one (cf. {@link reset/2}). If you need to
%% differentiate between unset and set entries, you must make sure that
%% the default value cannot be confused with the values of set entries.
%%
%% The array never shrinks automatically; if an index `I' has been used
%% successfully to set an entry, all indices in the range [0,`I'] will
%% stay accessible unless the array size is explicitly changed by
%% calling {@link resize/2}.
%%
%% Examples:
%% ```
%% %% Create a fixed-size array with entries 0-9 set to 'undefined'
%% A0 = array:new(10).
%% 10 = array:size(A0).
%%
%% %% Create an extendible array and set entry 17 to 'true',
%% %% causing the array to grow automatically
%% A1 = array:set(17, true, array:new()).
%% 18 = array:size(A1).
%%
%% %% Read back a stored value
%% true = array:get(17, A1).
%%
%% %% Accessing an unset entry returns the default value
%% undefined = array:get(3, A1).
%%
%% %% Accessing an entry beyond the last set entry also returns the
%% %% default value, if the array does not have fixed size
%% undefined = array:get(18, A1).
%%
%% %% "sparse" functions ignore default-valued entries
%% A2 = array:set(4, false, A1).
%% [{4, false}, {17, true}] = array:sparse_to_orddict(A2).
%%
%% %% An extendible array can be made fixed-size later
%% A3 = array:fix(A2).
%%
%% %% A fixed-size array does not grow automatically and does not
%% %% allow accesses beyond the last set entry
%% {'EXIT',{badarg,_}} = (catch array:set(18, true, A3)).
%% {'EXIT',{badarg,_}} = (catch array:get(18, A3)).
%% '''
%% @type array(). A functional, extendible array. The representation is
%% not documented and is subject to change without notice. Note that
%% arrays cannot be directly compared for equality.
-module(array).
-export([new/0, new/1, new/2, is_array/1, set/3, get/2, size/1,
sparse_size/1, default/1, reset/2, to_list/1, sparse_to_list/1,
from_list/1, from_list/2, to_orddict/1, sparse_to_orddict/1,
from_orddict/1, from_orddict/2, map/2, sparse_map/2, foldl/3,
foldr/3, sparse_foldl/3, sparse_foldr/3, fix/1, relax/1, is_fix/1,
resize/1, resize/2]).
-export_type([array/0, array/1]).
%%-define(TEST,1).
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-endif.
%% Developers:
%%
%% For OTP devs: Both tests and documentation is extracted from this
%% file, keep and update this file,
%% test are extracted with array_SUITE:extract_tests().
%% Doc with docb_gen array.erl
%%
%% The key to speed is to minimize the number of tests, on
%% large input. Always make the most probable path as short as possible.
%% In particular, keep in mind that for large trees, the probability of
%% a leaf node is small relative to that of an internal node.
%%
%% If you try to tweak the set_1 and get_1 loops: Measure, look at the
%% generated Beam code, and measure again! The argument order matters!
%% Representation:
%%
%% A tree is either a leaf, with LEAFSIZE elements (the "base"), an
%% internal node with LEAFSIZE+1 elements, or an unexpanded tree,
%% represented by a single integer: the number of elements that may be
%% stored in the tree when it is expanded. The last element of an
%% internal node caches the number of elements that may be stored in
%% each of its subtrees.
%%
%% Note that to update an entry in a tree of height h = log[b] n, the
%% total number of written words is (b+1)+(h-1)*(b+2), since tuples use
%% a header word on the heap. 4 is the optimal base for minimizing the
%% number of words written, but causes higher trees, which takes time.
%% The best compromise between speed and memory usage seems to lie
%% around 8-10. Measurements indicate that the optimum base for speed is
%% 24 - above that, it gets slower again due to the high memory usage.
%% Base 10 is a good choice, giving 2/3 of the possible speedup from
%% base 4, but only using 1/3 more memory. (Base 24 uses 65% more memory
%% per write than base 10, but the speedup is only 21%.)
-define(DEFAULT, undefined).
-define(LEAFSIZE, 10). % the "base"
-define(NODESIZE, ?LEAFSIZE). % (no reason to have a different size)
-define(NODEPATTERN(S), {_,_,_,_,_,_,_,_,_,_,S}). % NODESIZE+1 elements!
-define(NEW_NODE(S), % beware of argument duplication!
setelement((?NODESIZE+1),erlang:make_tuple((?NODESIZE+1),(S)),(S))).
-define(NEW_LEAF(D), erlang:make_tuple(?LEAFSIZE,(D))).
-define(NODELEAFS, ?NODESIZE*?LEAFSIZE).
%% These make the code a little easier to experiment with.
%% It turned out that using shifts (when NODESIZE=2^n) was not faster.
-define(reduce(X), ((X) div (?NODESIZE))).
-define(extend(X), ((X) * (?NODESIZE))).
%%--------------------------------------------------------------------------
-type element_tuple(T) ::
{T, T, T, T, T, T, T, T, T, T}
| {element_tuple(T), element_tuple(T), element_tuple(T),
element_tuple(T), element_tuple(T), element_tuple(T),
element_tuple(T), element_tuple(T), element_tuple(T),
element_tuple(T), non_neg_integer()}.
-type elements(T) :: non_neg_integer()
| element_tuple(T)
| nil(). % kill reference, for GC
-record(array, {size :: non_neg_integer(), %% number of defined entries
max :: non_neg_integer(), %% maximum number of entries
%% in current tree
default, %% the default value (usually 'undefined')
elements :: elements(_) %% the tuple tree
}).
-type array() :: array(term()).
-opaque array(Type) ::
#array{default :: Type, elements :: elements(Type)}.
%%
%% Types
%%
-type array_indx() :: non_neg_integer().
-type array_opt() :: {'fixed', boolean()} | 'fixed'
| {'default', Type :: term()}
| {'size', N :: non_neg_integer()}
| (N :: non_neg_integer()).
-type array_opts() :: array_opt() | [array_opt()].
-type indx_pair(Type) :: {Index :: array_indx(), Type}.
-type indx_pairs(Type) :: [indx_pair(Type)].
%%--------------------------------------------------------------------------
%% @doc Create a new, extendible array with initial size zero.
%% @equiv new([])
%%
%% @see new/1
%% @see new/2
-spec new() -> array().
new() ->
new([]).
%% @doc Create a new array according to the given options. By default,
%% the array is extendible and has initial size zero. Array indices
%% start at 0.
%%
%% `Options' is a single term or a list of terms, selected from the
%% following:
%% <dl>
%% <dt>`N::integer()' or `{size, N::integer()}'</dt>
%% <dd>Specifies the initial size of the array; this also implies
%% `{fixed, true}'. If `N' is not a nonnegative integer, the call
%% fails with reason `badarg'.</dd>
%% <dt>`fixed' or `{fixed, true}'</dt>
%% <dd>Creates a fixed-size array; see also {@link fix/1}.</dd>
%% <dt>`{fixed, false}'</dt>
%% <dd>Creates an extendible (non fixed-size) array.</dd>
%% <dt>`{default, Value}'</dt>
%% <dd>Sets the default value for the array to `Value'.</dd>
%% </dl>
%% Options are processed in the order they occur in the list, i.e.,
%% later options have higher precedence.
%%
%% The default value is used as the value of uninitialized entries, and
%% cannot be changed once the array has been created.
%%
%% Examples:
%% ```array:new(100)''' creates a fixed-size array of size 100.
%% ```array:new({default,0})''' creates an empty, extendible array
%% whose default value is 0.
%% ```array:new([{size,10},{fixed,false},{default,-1}])''' creates an
%% extendible array with initial size 10 whose default value is -1.
%%
%% @see new/0
%% @see new/2
%% @see set/3
%% @see get/2
%% @see from_list/2
%% @see fix/1
-spec new(Options :: array_opts()) -> array().
new(Options) ->
new_0(Options, 0, false).
%% @doc Create a new array according to the given size and options. If
%% `Size' is not a nonnegative integer, the call fails with reason
%% `badarg'. By default, the array has fixed size. Note that any size
%% specifications in `Options' will override the `Size' parameter.
%%
%% If `Options' is a list, this is simply equivalent to `new([{size,
%% Size} | Options]', otherwise it is equivalent to `new([{size, Size} |
%% [Options]]'. However, using this function directly is more efficient.
%%
%% Example:
%% ```array:new(100, {default,0})''' creates a fixed-size array of size
%% 100, whose default value is 0.
%%
%% @see new/1
-spec new(Size :: non_neg_integer(), Options :: array_opts()) -> array().
new(Size, Options) when is_integer(Size), Size >= 0 ->
new_0(Options, Size, true);
new(_, _) ->
erlang:error(badarg).
new_0(Options, Size, Fixed) when is_list(Options) ->
new_1(Options, Size, Fixed, ?DEFAULT);
new_0(Options, Size, Fixed) ->
new_1([Options], Size, Fixed, ?DEFAULT).
new_1([fixed | Options], Size, _, Default) ->
new_1(Options, Size, true, Default);
new_1([{fixed, Fixed} | Options], Size, _, Default)
when is_boolean(Fixed) ->
new_1(Options, Size, Fixed, Default);
new_1([{default, Default} | Options], Size, Fixed, _) ->
new_1(Options, Size, Fixed, Default);
new_1([{size, Size} | Options], _, _, Default)
when is_integer(Size), Size >= 0 ->
new_1(Options, Size, true, Default);
new_1([Size | Options], _, _, Default)
when is_integer(Size), Size >= 0 ->
new_1(Options, Size, true, Default);
new_1([], Size, Fixed, Default) ->
new(Size, Fixed, Default);
new_1(_Options, _Size, _Fixed, _Default) ->
erlang:error(badarg).
new(0, false, undefined) ->
%% Constant empty array
#array{size=0, max=?LEAFSIZE, elements=?LEAFSIZE};
new(Size, Fixed, Default) ->
E = find_max(Size - 1, ?LEAFSIZE),
M = if Fixed -> 0;
true -> E
end,
#array{size = Size, max = M, default = Default, elements = E}.
-spec find_max(integer(), integer()) -> integer().
find_max(I, M) when I >= M ->
find_max(I, ?extend(M));
find_max(_I, M) ->
M.
%% @doc Returns `true' if `X' appears to be an array, otherwise `false'.
%% Note that the check is only shallow; there is no guarantee that `X'
%% is a well-formed array representation even if this function returns
%% `true'.
-spec is_array(X :: term()) -> boolean().
is_array(#array{size = Size, max = Max})
when is_integer(Size), is_integer(Max) ->
true;
is_array(_) ->
false.
%% @doc Get the number of entries in the array. Entries are numbered
%% from 0 to `size(Array)-1'; hence, this is also the index of the first
%% entry that is guaranteed to not have been previously set.
%% @see set/3
%% @see sparse_size/1
-spec size(Array :: array()) -> non_neg_integer().
size(#array{size = N}) -> N;
size(_) -> erlang:error(badarg).
%% @doc Get the value used for uninitialized entries.
%%
%% @see new/2
-spec default(Array :: array(Type)) -> Value :: Type.
default(#array{default = D}) -> D;
default(_) -> erlang:error(badarg).
-ifdef(EUNIT).
new_test_() ->
N0 = ?LEAFSIZE,
N01 = N0+1,
N1 = ?NODESIZE*N0,
N11 = N1+1,
N2 = ?NODESIZE*N1,
[?_test(new()),
?_test(new([])),
?_test(new(10)),
?_test(new({size,10})),
?_test(new(fixed)),
?_test(new({fixed,true})),
?_test(new({fixed,false})),
?_test(new({default,undefined})),
?_test(new([{size,100},{fixed,false},{default,undefined}])),
?_test(new([100,fixed,{default,0}])),
?_assert(new() =:= new([])),
?_assert(new() =:= new([{size,0},{default,undefined},{fixed,false}])),
?_assert(new() =:= new(0, {fixed,false})),
?_assert(new(fixed) =:= new(0)),
?_assert(new(fixed) =:= new(0, [])),
?_assert(new(10) =:= new([{size,0},{size,5},{size,10}])),
?_assert(new(10) =:= new(0, {size,10})),
?_assert(new(10, []) =:= new(10, [{default,undefined},{fixed,true}])),
?_assertError(badarg, new(-1)),
?_assertError(badarg, new(10.0)),
?_assertError(badarg, new(undefined)),
?_assertError(badarg, new([undefined])),
?_assertError(badarg, new([{default,0} | fixed])),
?_assertError(badarg, new(-1, [])),
?_assertError(badarg, new(10.0, [])),
?_assertError(badarg, new(undefined, [])),
?_assertMatch(#array{size=0,max=N0,default=undefined,elements=N0},
new()),
?_assertMatch(#array{size=0,max=0,default=undefined,elements=N0},
new(fixed)),
?_assertMatch(#array{size=N0,max=N0,elements=N0},
new(N0, {fixed,false})),
?_assertMatch(#array{size=N01,max=N1,elements=N1},
new(N01, {fixed,false})),
?_assertMatch(#array{size=N1,max=N1,elements=N1},
new(N1, {fixed,false})),
?_assertMatch(#array{size=N11,max=N2,elements=N2},
new(N11, {fixed,false})),
?_assertMatch(#array{size=N2, max=N2, default=42,elements=N2},
new(N2, [{fixed,false},{default,42}])),
?_assert(0 =:= array:size(new())),
?_assert(17 =:= array:size(new(17))),
?_assert(100 =:= array:size(array:set(99,0,new()))),
?_assertError(badarg, array:size({bad_data,gives_error})),
?_assert(undefined =:= default(new())),
?_assert(4711 =:= default(new({default,4711}))),
?_assert(0 =:= default(new(10, {default,0}))),
?_assertError(badarg, default({bad_data,gives_error})),
?_assert(is_array(new())),
?_assert(false =:= is_array({foobar, 23, 23})),
?_assert(false =:= is_array(#array{size=bad})),
?_assert(false =:= is_array(#array{max=bad})),
?_assert(is_array(new(10))),
?_assert(is_array(new(10, {fixed,false})))
].
-endif.
%% @doc Fix the size of the array. This prevents it from growing
%% automatically upon insertion; see also {@link set/3}.
%% @see relax/1
-spec fix(Array :: array(Type)) -> array(Type).
fix(#array{}=A) ->
A#array{max = 0}.
%% @doc Check if the array has fixed size.
%% Returns `true' if the array is fixed, otherwise `false'.
%% @see fix/1
-spec is_fix(Array :: array()) -> boolean().
is_fix(#array{max = 0}) -> true;
is_fix(#array{}) -> false.
-ifdef(EUNIT).
fix_test_() ->
[?_assert(is_array(fix(new()))),
?_assert(fix(new()) =:= new(fixed)),
?_assertNot(is_fix(new())),
?_assertNot(is_fix(new([]))),
?_assertNot(is_fix(new({fixed,false}))),
?_assertNot(is_fix(new(10, {fixed,false}))),
?_assert(is_fix(new({fixed,true}))),
?_assert(is_fix(new(fixed))),
?_assert(is_fix(new(10))),
?_assert(is_fix(new(10, []))),
?_assert(is_fix(new(10, {fixed,true}))),
?_assert(is_fix(fix(new()))),
?_assert(is_fix(fix(new({fixed,false})))),
?_test(set(0, 17, new())),
?_assertError(badarg, set(0, 17, new(fixed))),
?_assertError(badarg, set(1, 42, fix(set(0, 17, new())))),
?_test(set(9, 17, new(10))),
?_assertError(badarg, set(10, 17, new(10))),
?_assertError(badarg, set(10, 17, fix(new(10, {fixed,false}))))
].
-endif.
%% @doc Make the array resizable. (Reverses the effects of {@link
%% fix/1}.)
%% @see fix/1
-spec relax(Array :: array(Type)) -> array(Type).
relax(#array{size = N}=A) ->
A#array{max = find_max(N-1, ?LEAFSIZE)}.
-ifdef(EUNIT).
relax_test_() ->
[?_assert(is_array(relax(new(fixed)))),
?_assertNot(is_fix(relax(fix(new())))),
?_assertNot(is_fix(relax(new(fixed)))),
?_assert(new() =:= relax(new(fixed))),
?_assert(new() =:= relax(new(0))),
?_assert(new(17, {fixed,false}) =:= relax(new(17))),
?_assert(new(100, {fixed,false})
=:= relax(fix(new(100, {fixed,false}))))
].
-endif.
%% @doc Change the size of the array. If `Size' is not a nonnegative
%% integer, the call fails with reason `badarg'. If the given array has
%% fixed size, the resulting array will also have fixed size.
-spec resize(Size :: non_neg_integer(), Array :: array(Type)) ->
array(Type).
resize(Size, #array{size = N, max = M, elements = E}=A)
when is_integer(Size), Size >= 0 ->
if Size > N ->
{E1, M1} = grow(Size-1, E,
if M > 0 -> M;
true -> find_max(N-1, ?LEAFSIZE)
end),
A#array{size = Size,
max = if M > 0 -> M1;
true -> M
end,
elements = E1};
Size < N ->
%% TODO: shrink physical representation when shrinking the array
A#array{size = Size};
true ->
A
end;
resize(_Size, _) ->
erlang:error(badarg).
%% @doc Change the size of the array to that reported by {@link
%% sparse_size/1}. If the given array has fixed size, the resulting
%% array will also have fixed size.
%% @equiv resize(sparse_size(Array), Array)
%% @see resize/2
%% @see sparse_size/1
-spec resize(Array :: array(Type)) -> array(Type).
resize(Array) ->
resize(sparse_size(Array), Array).
-ifdef(EUNIT).
resize_test_() ->
[?_assert(resize(0, new()) =:= new()),
?_assert(resize(99, new(99)) =:= new(99)),
?_assert(resize(99, relax(new(99))) =:= relax(new(99))),
?_assert(is_fix(resize(100, new(10)))),
?_assertNot(is_fix(resize(100, relax(new(10))))),
?_assert(array:size(resize(100, new())) =:= 100),
?_assert(array:size(resize(0, new(100))) =:= 0),
?_assert(array:size(resize(99, new(10))) =:= 99),
?_assert(array:size(resize(99, new(1000))) =:= 99),
?_assertError(badarg, set(99, 17, new(10))),
?_test(set(99, 17, resize(100, new(10)))),
?_assertError(badarg, set(100, 17, resize(100, new(10)))),
?_assert(array:size(resize(new())) =:= 0),
?_assert(array:size(resize(new(8))) =:= 0),
?_assert(array:size(resize(array:set(7, 0, new()))) =:= 8),
?_assert(array:size(resize(array:set(7, 0, new(10)))) =:= 8),
?_assert(array:size(resize(array:set(99, 0, new(10,{fixed,false}))))
=:= 100),
?_assert(array:size(resize(array:set(7, undefined, new()))) =:= 0),
?_assert(array:size(resize(array:from_list([1,2,3,undefined])))
=:= 3),
?_assert(array:size(
resize(array:from_orddict([{3,0},{17,0},{99,undefined}])))
=:= 18),
?_assertError(badarg, resize(foo, bad_argument))
].
-endif.
%% @doc Set entry `I' of the array to `Value'. If `I' is not a
%% nonnegative integer, or if the array has fixed size and `I' is larger
%% than the maximum index, the call fails with reason `badarg'.
%%
%% If the array does not have fixed size, and `I' is greater than
%% `size(Array)-1', the array will grow to size `I+1'.
%%
%% @see get/2
%% @see reset/2
-spec set(I :: array_indx(), Value :: Type, Array :: array(Type)) -> array(Type).
set(I, Value, #array{size = N, max = M, default = D, elements = E}=A)
when is_integer(I), I >= 0 ->
if I < N ->
A#array{elements = set_1(I, E, Value, D)};
I < M ->
%% (note that this cannot happen if M == 0, since N >= 0)
A#array{size = I+1, elements = set_1(I, E, Value, D)};
M > 0 ->
{E1, M1} = grow(I, E, M),
A#array{size = I+1, max = M1,
elements = set_1(I, E1, Value, D)};
true ->
erlang:error(badarg)
end;
set(_I, _V, _A) ->
erlang:error(badarg).
%% See get_1/3 for details about switching and the NODEPATTERN macro.
set_1(I, E=?NODEPATTERN(S), X, D) ->
I1 = I div S + 1,
setelement(I1, E, set_1(I rem S, element(I1, E), X, D));
set_1(I, E, X, D) when is_integer(E) ->
expand(I, E, X, D);
set_1(I, E, X, _D) ->
setelement(I+1, E, X).
%% Enlarging the array upwards to accommodate an index `I'
grow(I, E, _M) when is_integer(E) ->
M1 = find_max(I, E),
{M1, M1};
grow(I, E, M) ->
grow_1(I, E, M).
grow_1(I, E, M) when I >= M ->
grow(I, setelement(1, ?NEW_NODE(M), E), ?extend(M));
grow_1(_I, E, M) ->
{E, M}.
%% Insert an element in an unexpanded node, expanding it as necessary.
expand(I, S, X, D) when S > ?LEAFSIZE ->
S1 = ?reduce(S),
setelement(I div S1 + 1, ?NEW_NODE(S1),
expand(I rem S1, S1, X, D));
expand(I, _S, X, D) ->
setelement(I+1, ?NEW_LEAF(D), X).
%% @doc Get the value of entry `I'. If `I' is not a nonnegative
%% integer, or if the array has fixed size and `I' is larger than the
%% maximum index, the call fails with reason `badarg'.
%%
%% If the array does not have fixed size, this function will return the
%% default value for any index `I' greater than `size(Array)-1'.
%% @see set/3
-spec get(I :: array_indx(), Array :: array(Type)) -> Value :: Type.
get(I, #array{size = N, max = M, elements = E, default = D})
when is_integer(I), I >= 0 ->
if I < N ->
get_1(I, E, D);
M > 0 ->
D;
true ->
erlang:error(badarg)
end;
get(_I, _A) ->
erlang:error(badarg).
%% The use of NODEPATTERN(S) to select the right clause is just a hack,
%% but it is the only way to get the maximum speed out of this loop
%% (using the Beam compiler in OTP 11).
get_1(I, E=?NODEPATTERN(S), D) ->
get_1(I rem S, element(I div S + 1, E), D);
get_1(_I, E, D) when is_integer(E) ->
D;
get_1(I, E, _D) ->
element(I+1, E).
%% @doc Reset entry `I' to the default value for the array.
%% If the value of entry `I' is the default value the array will be
%% returned unchanged. Reset will never change size of the array.
%% Shrinking can be done explicitly by calling {@link resize/2}.
%%
%% If `I' is not a nonnegative integer, or if the array has fixed size
%% and `I' is larger than the maximum index, the call fails with reason
%% `badarg'; cf. {@link set/3}
%%
%% @see new/2
%% @see set/3
%% TODO: a reset_range function
-spec reset(I :: array_indx(), Array :: array(Type)) -> array(Type).
reset(I, #array{size = N, max = M, default = D, elements = E}=A)
when is_integer(I), I >= 0 ->
if I < N ->
try A#array{elements = reset_1(I, E, D)}
catch throw:default -> A
end;
M > 0 ->
A;
true ->
erlang:error(badarg)
end;
reset(_I, _A) ->
erlang:error(badarg).
reset_1(I, E=?NODEPATTERN(S), D) ->
I1 = I div S + 1,
setelement(I1, E, reset_1(I rem S, element(I1, E), D));
reset_1(_I, E, _D) when is_integer(E) ->
throw(default);
reset_1(I, E, D) ->
Indx = I+1,
case element(Indx, E) of
D -> throw(default);
_ -> setelement(I+1, E, D)
end.
-ifdef(EUNIT).
set_get_test_() ->
N0 = ?LEAFSIZE,
N1 = ?NODESIZE*N0,
[?_assert(array:get(0, new()) =:= undefined),
?_assert(array:get(1, new()) =:= undefined),
?_assert(array:get(99999, new()) =:= undefined),
?_assert(array:get(0, new(1)) =:= undefined),
?_assert(array:get(0, new(1,{default,0})) =:= 0),
?_assert(array:get(9, new(10)) =:= undefined),
?_assertError(badarg, array:get(0, new(fixed))),
?_assertError(badarg, array:get(1, new(1))),
?_assertError(badarg, array:get(-1, new(1))),
?_assertError(badarg, array:get(10, new(10))),
?_assertError(badarg, array:set(-1, foo, new(10))),
?_assertError(badarg, array:set(10, foo, no_array)),
?_assert(array:size(set(0, 17, new())) =:= 1),
?_assert(array:size(set(N1-1, 17, new())) =:= N1),
?_assert(array:size(set(0, 42, set(0, 17, new()))) =:= 1),
?_assert(array:size(set(9, 42, set(0, 17, new()))) =:= 10),
?_assert(array:get(0, set(0, 17, new())) =:= 17),
?_assert(array:get(0, set(1, 17, new())) =:= undefined),
?_assert(array:get(1, set(1, 17, new())) =:= 17),
?_assert(array:get(0, fix(set(0, 17, new()))) =:= 17),
?_assertError(badarg, array:get(1, fix(set(0, 17, new())))),
?_assert(array:get(N1-2, set(N1-1, 17, new())) =:= undefined),
?_assert(array:get(N1-1, set(N1-1, 17, new())) =:= 17),
?_assertError(badarg, array:get(N1, fix(set(N1-1, 17, new())))),
?_assert(array:get(0, set(0, 42, set(0, 17, new()))) =:= 42),
?_assertError(badarg, array:get(0, reset(11, new([{size,10}])))),
?_assertError(badarg, array:get(0, reset(-1, new([{size,10}])))),
?_assert(array:get(0, reset(0, new())) =:= undefined),
?_assert(array:get(0, reset(0, set(0, 17, new()))) =:= undefined),
?_assert(array:get(0, reset(9, set(9, 17, new()))) =:= undefined),
?_assert(array:get(0, reset(11, set(11, 17, new()))) =:= undefined),
?_assert(array:get(0, reset(11, set(12, 17, new()))) =:= undefined),
?_assert(array:get(0, reset(1, set(12, 17, new()))) =:= undefined),
?_assert(array:get(0, reset(11, new())) =:= undefined),
?_assert(array:get(0, reset(0, set(0, 17, new({default,42})))) =:= 42),
?_assert(array:get(0, reset(0, new({default,42}))) =:= 42)
].
-endif.
%% @doc Converts the array to a list.
%%
%% @see from_list/2
%% @see sparse_to_list/1
-spec to_list(Array :: array(Type)) -> list(Value :: Type).
to_list(#array{size = 0}) ->
[];
to_list(#array{size = N, elements = E, default = D}) ->
to_list_1(E, D, N - 1);
to_list(_) ->
erlang:error(badarg).
%% this part handles the rightmost subtrees
to_list_1(E=?NODEPATTERN(S), D, I) ->
N = I div S,
to_list_3(N, D, to_list_1(element(N+1, E), D, I rem S), E);
to_list_1(E, D, I) when is_integer(E) ->
push(I+1, D, []);
to_list_1(E, _D, I) ->
push_tuple(I+1, E, []).
%% this part handles full trees only
to_list_2(E=?NODEPATTERN(_S), D, L) ->
to_list_3(?NODESIZE, D, L, E);
to_list_2(E, D, L) when is_integer(E) ->
push(E, D, L);
to_list_2(E, _D, L) ->
push_tuple(?LEAFSIZE, E, L).
to_list_3(0, _D, L, _E) ->
L;
to_list_3(N, D, L, E) ->
to_list_3(N-1, D, to_list_2(element(N, E), D, L), E).
push(0, _E, L) ->
L;
push(N, E, L) ->
push(N - 1, E, [E | L]).
push_tuple(0, _T, L) ->
L;
push_tuple(N, T, L) ->
push_tuple(N - 1, T, [element(N, T) | L]).
-ifdef(EUNIT).
to_list_test_() ->
N0 = ?LEAFSIZE,
[?_assert([] =:= to_list(new())),
?_assert([undefined] =:= to_list(new(1))),
?_assert([undefined,undefined] =:= to_list(new(2))),
?_assert(lists:duplicate(N0,0) =:= to_list(new(N0,{default,0}))),
?_assert(lists:duplicate(N0+1,1) =:= to_list(new(N0+1,{default,1}))),
?_assert(lists:duplicate(N0+2,2) =:= to_list(new(N0+2,{default,2}))),
?_assert(lists:duplicate(666,6) =:= to_list(new(666,{default,6}))),
?_assert([1,2,3] =:= to_list(set(2,3,set(1,2,set(0,1,new()))))),
?_assert([3,2,1] =:= to_list(set(0,3,set(1,2,set(2,1,new()))))),
?_assert([1|lists:duplicate(N0-2,0)++[1]] =:=
to_list(set(N0-1,1,set(0,1,new({default,0}))))),
?_assert([1|lists:duplicate(N0-1,0)++[1]] =:=
to_list(set(N0,1,set(0,1,new({default,0}))))),
?_assert([1|lists:duplicate(N0,0)++[1]] =:=
to_list(set(N0+1,1,set(0,1,new({default,0}))))),
?_assert([1|lists:duplicate(N0*3,0)++[1]] =:=
to_list(set((N0*3)+1,1,set(0,1,new({default,0}))))),
?_assertError(badarg, to_list(no_array))
].
-endif.
%% @doc Converts the array to a list, skipping default-valued entries.
%%
%% @see to_list/1
-spec sparse_to_list(Array :: array(Type)) -> list(Value :: Type).
sparse_to_list(#array{size = 0}) ->
[];
sparse_to_list(#array{size = N, elements = E, default = D}) ->
sparse_to_list_1(E, D, N - 1);
sparse_to_list(_) ->
erlang:error(badarg).
%% see to_list/1 for details
sparse_to_list_1(E=?NODEPATTERN(S), D, I) ->
N = I div S,
sparse_to_list_3(N, D,
sparse_to_list_1(element(N+1, E), D, I rem S),
E);
sparse_to_list_1(E, _D, _I) when is_integer(E) ->
[];
sparse_to_list_1(E, D, I) ->
sparse_push_tuple(I+1, D, E, []).
sparse_to_list_2(E=?NODEPATTERN(_S), D, L) ->
sparse_to_list_3(?NODESIZE, D, L, E);
sparse_to_list_2(E, _D, L) when is_integer(E) ->
L;
sparse_to_list_2(E, D, L) ->
sparse_push_tuple(?LEAFSIZE, D, E, L).
sparse_to_list_3(0, _D, L, _E) ->
L;
sparse_to_list_3(N, D, L, E) ->
sparse_to_list_3(N-1, D, sparse_to_list_2(element(N, E), D, L), E).
sparse_push_tuple(0, _D, _T, L) ->
L;
sparse_push_tuple(N, D, T, L) ->
case element(N, T) of
D -> sparse_push_tuple(N - 1, D, T, L);
E -> sparse_push_tuple(N - 1, D, T, [E | L])
end.
-ifdef(EUNIT).
sparse_to_list_test_() ->
N0 = ?LEAFSIZE,
[?_assert([] =:= sparse_to_list(new())),
?_assert([] =:= sparse_to_list(new(1))),
?_assert([] =:= sparse_to_list(new(1,{default,0}))),
?_assert([] =:= sparse_to_list(new(2))),
?_assert([] =:= sparse_to_list(new(2,{default,0}))),
?_assert([] =:= sparse_to_list(new(N0,{default,0}))),
?_assert([] =:= sparse_to_list(new(N0+1,{default,1}))),
?_assert([] =:= sparse_to_list(new(N0+2,{default,2}))),
?_assert([] =:= sparse_to_list(new(666,{default,6}))),
?_assert([1,2,3] =:= sparse_to_list(set(2,3,set(1,2,set(0,1,new()))))),
?_assert([3,2,1] =:= sparse_to_list(set(0,3,set(1,2,set(2,1,new()))))),
?_assert([0,1] =:= sparse_to_list(set(N0-1,1,set(0,0,new())))),
?_assert([0,1] =:= sparse_to_list(set(N0,1,set(0,0,new())))),
?_assert([0,1] =:= sparse_to_list(set(N0+1,1,set(0,0,new())))),
?_assert([0,1,2] =:= sparse_to_list(set(N0*10+1,2,set(N0*2+1,1,set(0,0,new()))))),
?_assertError(badarg, sparse_to_list(no_array))
].
-endif.
%% @equiv from_list(List, undefined)
-spec from_list(List :: list(Value :: Type)) -> array(Type).
from_list(List) ->
from_list(List, undefined).
%% @doc Convert a list to an extendible array. `Default' is used as the value
%% for uninitialized entries of the array. If `List' is not a proper list,
%% the call fails with reason `badarg'.
%%
%% @see new/2
%% @see to_list/1
-spec from_list(List :: list(Value :: Type), Default :: term()) -> array(Type).
from_list([], Default) ->
new({default,Default});
from_list(List, Default) when is_list(List) ->
{E, N, M} = from_list_1(?LEAFSIZE, List, Default, 0, [], []),
#array{size = N, max = M, default = Default, elements = E};
from_list(_, _) ->
erlang:error(badarg).
%% Note: A cleaner but slower algorithm is to first take the length of
%% the list and compute the max size of the final tree, and then
%% decompose the list. The below algorithm is almost twice as fast,
%% however.
%% Building the leaf nodes (padding the last one as necessary) and
%% counting the total number of elements.
from_list_1(0, Xs, D, N, As, Es) ->
E = list_to_tuple(lists:reverse(As)),
case Xs of
[] ->
case Es of
[] ->
{E, N, ?LEAFSIZE};
_ ->
from_list_2_0(N, [E | Es], ?LEAFSIZE)
end;
[_|_] ->
from_list_1(?LEAFSIZE, Xs, D, N, [], [E | Es]);
_ ->
erlang:error(badarg)
end;
from_list_1(I, Xs, D, N, As, Es) ->
case Xs of
[X | Xs1] ->
from_list_1(I-1, Xs1, D, N+1, [X | As], Es);
_ ->
from_list_1(I-1, Xs, D, N, [D | As], Es)
end.
%% Building the internal nodes (note that the input is reversed).
from_list_2_0(N, Es, S) ->
from_list_2(?NODESIZE, pad((N-1) div S + 1, ?NODESIZE, S, Es),
S, N, [S], []).
from_list_2(0, Xs, S, N, As, Es) ->
E = list_to_tuple(As),
case Xs of
[] ->
case Es of
[] ->
{E, N, ?extend(S)};
_ ->
from_list_2_0(N, lists:reverse([E | Es]),
?extend(S))
end;
_ ->
from_list_2(?NODESIZE, Xs, S, N, [S], [E | Es])
end;
from_list_2(I, [X | Xs], S, N, As, Es) ->
from_list_2(I-1, Xs, S, N, [X | As], Es).
%% left-padding a list Es with elements P to the nearest multiple of K
%% elements from N (adding 0 to K-1 elements).
pad(N, K, P, Es) ->
push((K - (N rem K)) rem K, P, Es).
-ifdef(EUNIT).
from_list_test_() ->
N0 = ?LEAFSIZE,
N1 = ?NODESIZE*N0,
N2 = ?NODESIZE*N1,
N3 = ?NODESIZE*N2,
N4 = ?NODESIZE*N3,
[?_assert(array:size(from_list([])) =:= 0),
?_assert(array:is_fix(from_list([])) =:= false),
?_assert(array:size(from_list([undefined])) =:= 1),
?_assert(array:is_fix(from_list([undefined])) =:= false),
?_assert(array:size(from_list(lists:seq(1,N1))) =:= N1),
?_assert(to_list(from_list(lists:seq(1,N0))) =:= lists:seq(1,N0)),
?_assert(to_list(from_list(lists:seq(1,N0+1))) =:= lists:seq(1,N0+1)),
?_assert(to_list(from_list(lists:seq(1,N0+2))) =:= lists:seq(1,N0+2)),
?_assert(to_list(from_list(lists:seq(1,N2))) =:= lists:seq(1,N2)),
?_assert(to_list(from_list(lists:seq(1,N2+1))) =:= lists:seq(1,N2+1)),
?_assert(to_list(from_list(lists:seq(0,N3))) =:= lists:seq(0,N3)),
?_assert(to_list(from_list(lists:seq(0,N4))) =:= lists:seq(0,N4)),
?_assertError(badarg, from_list([a,b,a,c|d])),
?_assertError(badarg, from_list(no_array))
].
-endif.
%% @doc Convert the array to an ordered list of pairs `{Index, Value}'.
%%
%% @see from_orddict/2
%% @see sparse_to_orddict/1
-spec to_orddict(Array :: array(Type)) -> indx_pairs(Value :: Type).
to_orddict(#array{size = 0}) ->
[];
to_orddict(#array{size = N, elements = E, default = D}) ->
I = N - 1,
to_orddict_1(E, I, D, I);
to_orddict(_) ->
erlang:error(badarg).
%% see to_list/1 for comparison
to_orddict_1(E=?NODEPATTERN(S), R, D, I) ->
N = I div S,
I1 = I rem S,
to_orddict_3(N, R - I1 - 1, D,
to_orddict_1(element(N+1, E), R, D, I1),
E, S);
to_orddict_1(E, R, D, I) when is_integer(E) ->
push_pairs(I+1, R, D, []);
to_orddict_1(E, R, _D, I) ->
push_tuple_pairs(I+1, R, E, []).
to_orddict_2(E=?NODEPATTERN(S), R, D, L) ->
to_orddict_3(?NODESIZE, R, D, L, E, S);
to_orddict_2(E, R, D, L) when is_integer(E) ->
push_pairs(E, R, D, L);
to_orddict_2(E, R, _D, L) ->
push_tuple_pairs(?LEAFSIZE, R, E, L).
to_orddict_3(0, _R, _D, L, _E, _S) -> %% when is_integer(R) ->
L;
to_orddict_3(N, R, D, L, E, S) ->
to_orddict_3(N-1, R - S, D,
to_orddict_2(element(N, E), R, D, L),
E, S).
-spec push_pairs(non_neg_integer(), array_indx(), term(), indx_pairs(Type)) ->
indx_pairs(Type).
push_pairs(0, _I, _E, L) ->
L;
push_pairs(N, I, E, L) ->
push_pairs(N-1, I-1, E, [{I, E} | L]).
-spec push_tuple_pairs(non_neg_integer(), array_indx(), term(), indx_pairs(Type)) ->
indx_pairs(Type).
push_tuple_pairs(0, _I, _T, L) ->
L;
push_tuple_pairs(N, I, T, L) ->
push_tuple_pairs(N-1, I-1, T, [{I, element(N, T)} | L]).
-ifdef(EUNIT).
to_orddict_test_() ->
N0 = ?LEAFSIZE,
[?_assert([] =:= to_orddict(new())),
?_assert([{0,undefined}] =:= to_orddict(new(1))),
?_assert([{0,undefined},{1,undefined}] =:= to_orddict(new(2))),
?_assert([{N,0}||N<-lists:seq(0,N0-1)]
=:= to_orddict(new(N0,{default,0}))),
?_assert([{N,1}||N<-lists:seq(0,N0)]
=:= to_orddict(new(N0+1,{default,1}))),
?_assert([{N,2}||N<-lists:seq(0,N0+1)]
=:= to_orddict(new(N0+2,{default,2}))),
?_assert([{N,6}||N<-lists:seq(0,665)]
=:= to_orddict(new(666,{default,6}))),
?_assert([{0,1},{1,2},{2,3}] =:=
to_orddict(set(2,3,set(1,2,set(0,1,new()))))),
?_assert([{0,3},{1,2},{2,1}] =:=
to_orddict(set(0,3,set(1,2,set(2,1,new()))))),
?_assert([{0,1}|[{N,0}||N<-lists:seq(1,N0-2)]++[{N0-1,1}]]
=:= to_orddict(set(N0-1,1,set(0,1,new({default,0}))))),
?_assert([{0,1}|[{N,0}||N<-lists:seq(1,N0-1)]++[{N0,1}]]
=:= to_orddict(set(N0,1,set(0,1,new({default,0}))))),
?_assert([{0,1}|[{N,0}||N<-lists:seq(1,N0)]++[{N0+1,1}]]
=:= to_orddict(set(N0+1,1,set(0,1,new({default,0}))))),
?_assert([{0,0} | [{N,undefined}||N<-lists:seq(1,N0*2)]] ++
[{N0*2+1,1} | [{N,undefined}||N<-lists:seq(N0*2+2,N0*10)]] ++
[{N0*10+1,2}] =:=
to_orddict(set(N0*10+1,2,set(N0*2+1,1,set(0,0,new()))))),
?_assertError(badarg, to_orddict(no_array))
].
-endif.
%% @doc Convert the array to an ordered list of pairs `{Index, Value}',
%% skipping default-valued entries.
%%
%% @see to_orddict/1
-spec sparse_to_orddict(Array :: array(Type)) -> indx_pairs(Value :: Type).
sparse_to_orddict(#array{size = 0}) ->
[];
sparse_to_orddict(#array{size = N, elements = E, default = D}) ->
I = N - 1,
sparse_to_orddict_1(E, I, D, I);
sparse_to_orddict(_) ->
erlang:error(badarg).
%% see to_orddict/1 for details
sparse_to_orddict_1(E=?NODEPATTERN(S), R, D, I) ->
N = I div S,
I1 = I rem S,
sparse_to_orddict_3(N, R - I1 - 1, D,
sparse_to_orddict_1(element(N+1, E), R, D, I1),
E, S);
sparse_to_orddict_1(E, _R, _D, _I) when is_integer(E) ->
[];
sparse_to_orddict_1(E, R, D, I) ->
sparse_push_tuple_pairs(I+1, R, D, E, []).
sparse_to_orddict_2(E=?NODEPATTERN(S), R, D, L) ->
sparse_to_orddict_3(?NODESIZE, R, D, L, E, S);
sparse_to_orddict_2(E, _R, _D, L) when is_integer(E) ->
L;
sparse_to_orddict_2(E, R, D, L) ->
sparse_push_tuple_pairs(?LEAFSIZE, R, D, E, L).
sparse_to_orddict_3(0, _R, _D, L, _E, _S) -> % when is_integer(R) ->
L;
sparse_to_orddict_3(N, R, D, L, E, S) ->
sparse_to_orddict_3(N-1, R - S, D,
sparse_to_orddict_2(element(N, E), R, D, L),
E, S).
-spec sparse_push_tuple_pairs(non_neg_integer(), array_indx(),
_, _, indx_pairs(Type)) -> indx_pairs(Type).
sparse_push_tuple_pairs(0, _I, _D, _T, L) ->
L;
sparse_push_tuple_pairs(N, I, D, T, L) ->
case element(N, T) of
D -> sparse_push_tuple_pairs(N-1, I-1, D, T, L);
E -> sparse_push_tuple_pairs(N-1, I-1, D, T, [{I, E} | L])
end.
-ifdef(EUNIT).
sparse_to_orddict_test_() ->
N0 = ?LEAFSIZE,
[?_assert([] =:= sparse_to_orddict(new())),
?_assert([] =:= sparse_to_orddict(new(1))),
?_assert([] =:= sparse_to_orddict(new(1,{default,0}))),
?_assert([] =:= sparse_to_orddict(new(2))),
?_assert([] =:= sparse_to_orddict(new(2,{default,0}))),
?_assert([] =:= sparse_to_orddict(new(N0,{default,0}))),
?_assert([] =:= sparse_to_orddict(new(N0+1,{default,1}))),
?_assert([] =:= sparse_to_orddict(new(N0+2,{default,2}))),
?_assert([] =:= sparse_to_orddict(new(666,{default,6}))),
?_assert([{0,1},{1,2},{2,3}] =:=
sparse_to_orddict(set(2,3,set(1,2,set(0,1,new()))))),
?_assert([{0,3},{1,2},{2,1}] =:=
sparse_to_orddict(set(0,3,set(1,2,set(2,1,new()))))),
?_assert([{0,1},{N0-1,1}] =:=
sparse_to_orddict(set(N0-1,1,set(0,1,new({default,0}))))),
?_assert([{0,1},{N0,1}] =:=
sparse_to_orddict(set(N0,1,set(0,1,new({default,0}))))),
?_assert([{0,1},{N0+1,1}] =:=
sparse_to_orddict(set(N0+1,1,set(0,1,new({default,0}))))),
?_assert([{0,0},{N0*2+1,1},{N0*10+1,2}] =:=
sparse_to_orddict(set(N0*10+1,2,set(N0*2+1,1,set(0,0,new()))))),
?_assertError(badarg, sparse_to_orddict(no_array))
].
-endif.
%% @equiv from_orddict(Orddict, undefined)
-spec from_orddict(Orddict :: indx_pairs(Value :: Type)) -> array(Type).
from_orddict(Orddict) ->
from_orddict(Orddict, undefined).
%% @doc Convert an ordered list of pairs `{Index, Value}' to a
%% corresponding extendible array. `Default' is used as the value for
%% uninitialized entries of the array. If `List' is not a proper,
%% ordered list of pairs whose first elements are nonnegative
%% integers, the call fails with reason `badarg'.
%%
%% @see new/2
%% @see to_orddict/1
-spec from_orddict(Orddict :: indx_pairs(Value :: Type), Default :: Type) ->
array(Type).
from_orddict([], Default) ->
new({default,Default});
from_orddict(List, Default) when is_list(List) ->
{E, N, M} = from_orddict_0(List, 0, ?LEAFSIZE, Default, []),
#array{size = N, max = M, default = Default, elements = E};
from_orddict(_, _) ->
erlang:error(badarg).
%% 2 pass implementation, first pass builds the needed leaf nodes
%% and adds hole sizes.
%% (inserts default elements for missing list entries in the leafs
%% and pads the last tuple if necessary).
%% Second pass builds the tree from the leafs and the holes.
%%
%% Doesn't build/expand unnecessary leaf nodes which costs memory
%% and time for sparse arrays.
from_orddict_0([], N, _Max, _D, Es) ->
%% Finished, build the resulting tree
case Es of
[E] ->
{E, N, ?LEAFSIZE};
_ ->
collect_leafs(N, Es, ?LEAFSIZE)
end;
from_orddict_0(Xs=[{Ix1, _}|_], Ix, Max0, D, Es0)
when Ix1 > Max0, is_integer(Ix1) ->
%% We have a hole larger than a leaf
Hole = Ix1-Ix,
Step = Hole - (Hole rem ?LEAFSIZE),
Next = Ix+Step,
from_orddict_0(Xs, Next, Next+?LEAFSIZE, D, [Step|Es0]);
from_orddict_0(Xs0=[{_, _}|_], Ix0, Max, D, Es) ->
%% Fill a leaf
{Xs,E,Ix} = from_orddict_1(Ix0, Max, Xs0, Ix0, D, []),
from_orddict_0(Xs, Ix, Ix+?LEAFSIZE, D, [E|Es]);
from_orddict_0(Xs, _, _, _,_) ->
erlang:error({badarg, Xs}).
from_orddict_1(Ix, Ix, Xs, N, _D, As) ->
%% Leaf is full
E = list_to_tuple(lists:reverse(As)),
{Xs, E, N};
from_orddict_1(Ix, Max, Xs, N0, D, As) ->
case Xs of
[{Ix, Val} | Xs1] ->
N = Ix+1,
from_orddict_1(N, Max, Xs1, N, D, [Val | As]);
[{Ix1, _} | _] when is_integer(Ix1), Ix1 > Ix ->
N = Ix+1,
from_orddict_1(N, Max, Xs, N, D, [D | As]);
[_ | _] ->
erlang:error({badarg, Xs});
_ ->
from_orddict_1(Ix+1, Max, Xs, N0, D, [D | As])
end.
%% Es is reversed i.e. starting from the largest leafs
collect_leafs(N, Es, S) ->
I = (N-1) div S + 1,
Pad = ((?NODESIZE - (I rem ?NODESIZE)) rem ?NODESIZE) * S,
case Pad of
0 ->
collect_leafs(?NODESIZE, Es, S, N, [S], []);
_ -> %% Pad the end
collect_leafs(?NODESIZE, [Pad|Es], S, N, [S], [])
end.
collect_leafs(0, Xs, S, N, As, Es) ->
E = list_to_tuple(As),
case Xs of
[] ->
case Es of
[] ->
{E, N, ?extend(S)};
_ ->
collect_leafs(N, lists:reverse([E | Es]),
?extend(S))
end;
_ ->
collect_leafs(?NODESIZE, Xs, S, N, [S], [E | Es])
end;
collect_leafs(I, [X | Xs], S, N, As0, Es0)
when is_integer(X) ->
%% A hole, pad accordingly.
Step0 = (X div S),
if
Step0 < I ->
As = push(Step0, S, As0),
collect_leafs(I-Step0, Xs, S, N, As, Es0);
I =:= ?NODESIZE ->
Step = Step0 rem ?NODESIZE,
As = push(Step, S, As0),
collect_leafs(I-Step, Xs, S, N, As, [X|Es0]);
I =:= Step0 ->
As = push(I, S, As0),
collect_leafs(0, Xs, S, N, As, Es0);
true ->
As = push(I, S, As0),
Step = Step0 - I,
collect_leafs(0, [Step*S|Xs], S, N, As, Es0)
end;
collect_leafs(I, [X | Xs], S, N, As, Es) ->
collect_leafs(I-1, Xs, S, N, [X | As], Es);
collect_leafs(?NODESIZE, [], S, N, [_], Es) ->
collect_leafs(N, lists:reverse(Es), ?extend(S)).
-ifdef(EUNIT).
from_orddict_test_() ->
N0 = ?LEAFSIZE,
N1 = ?NODESIZE*N0,
N2 = ?NODESIZE*N1,
N3 = ?NODESIZE*N2,
N4 = ?NODESIZE*N3,
[?_assert(array:size(from_orddict([])) =:= 0),
?_assert(array:is_fix(from_orddict([])) =:= false),
?_assert(array:size(from_orddict([{0,undefined}])) =:= 1),
?_assert(array:is_fix(from_orddict([{0,undefined}])) =:= false),
?_assert(array:size(from_orddict([{N0-1,undefined}])) =:= N0),
?_assert(array:size(from_orddict([{N,0}||N<-lists:seq(0,N1-1)]))
=:= N1),
?_assertError({badarg,_}, from_orddict([foo])),
?_assertError({badarg,_}, from_orddict([{200,foo},{1,bar}])),
?_assertError({badarg,_}, from_orddict([{N,0}||N<-lists:seq(0,N0-1)] ++ not_a_list)),
?_assertError(badarg, from_orddict(no_array)),
?_assert(?LET(L, [{N,0}||N<-lists:seq(0,N0-1)],
L =:= to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N,0}||N<-lists:seq(0,N0)],
L =:= to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N,0}||N<-lists:seq(0,N2-1)],
L =:= to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N,0}||N<-lists:seq(0,N2)],
L =:= to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N,0}||N<-lists:seq(0,N3-1)],
L =:= to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N,0}||N<-lists:seq(0,N4-1)],
L =:= to_orddict(from_orddict(L)))),
%% Hole in the begining
?_assert(?LET(L, [{0,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N0,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N1,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N3,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N4,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N0-1,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N1-1,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N3-1,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{N4-1,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
%% Hole in middle
?_assert(?LET(L, [{0,0},{N0,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{0,0},{N1,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{0,0},{N3,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{0,0},{N4,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{0,0},{N0-1,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{0,0},{N1-1,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{0,0},{N3-1,0}],
L =:= sparse_to_orddict(from_orddict(L)))),
?_assert(?LET(L, [{0,0},{N4-1,0}],
L =:= sparse_to_orddict(from_orddict(L))))
].
-endif.
%% Function = (Index::integer(), Value::term()) -> term()
%% @doc Map the given function onto each element of the array. The
%% elements are visited in order from the lowest index to the highest.
%% If `Function' is not a function, the call fails with reason `badarg'.
%%
%% @see foldl/3
%% @see foldr/3
%% @see sparse_map/2
-spec map(Function, Array :: array(Type1)) -> array(Type2) when
Function :: fun((Index :: array_indx(), Type1) -> Type2).
map(Function, Array=#array{size = N, elements = E, default = D})
when is_function(Function, 2) ->
if N > 0 ->
A = Array#array{elements = []}, % kill reference, for GC
A#array{elements = map_1(N-1, E, 0, Function, D)};
true ->
Array
end;
map(_, _) ->
erlang:error(badarg).
%% It might be simpler to traverse the array right-to-left, as done e.g.
%% in the to_orddict/1 function, but it is better to guarantee
%% left-to-right application over the elements - that is more likely to
%% be a generally useful property.
map_1(N, E=?NODEPATTERN(S), Ix, F, D) ->
list_to_tuple(lists:reverse([S | map_2(1, E, Ix, F, D, [],
N div S + 1, N rem S, S)]));
map_1(N, E, Ix, F, D) when is_integer(E) ->
map_1(N, unfold(E, D), Ix, F, D);
map_1(N, E, Ix, F, D) ->
list_to_tuple(lists:reverse(map_3(1, E, Ix, F, D, N+1, []))).
map_2(I, E, Ix, F, D, L, I, R, _S) ->
map_2_1(I+1, E, [map_1(R, element(I, E), Ix, F, D) | L]);
map_2(I, E, Ix, F, D, L, N, R, S) ->
map_2(I+1, E, Ix + S, F, D,
[map_1(S-1, element(I, E), Ix, F, D) | L],
N, R, S).
map_2_1(I, E, L) when I =< ?NODESIZE ->
map_2_1(I+1, E, [element(I, E) | L]);
map_2_1(_I, _E, L) ->
L.
-spec map_3(pos_integer(), _, array_indx(),
fun((array_indx(),_) -> _), _, non_neg_integer(), [X]) -> [X].
map_3(I, E, Ix, F, D, N, L) when I =< N ->
map_3(I+1, E, Ix+1, F, D, N, [F(Ix, element(I, E)) | L]);
map_3(I, E, Ix, F, D, N, L) when I =< ?LEAFSIZE ->
map_3(I+1, E, Ix+1, F, D, N, [D | L]);
map_3(_I, _E, _Ix, _F, _D, _N, L) ->
L.
unfold(S, _D) when S > ?LEAFSIZE ->
?NEW_NODE(?reduce(S));
unfold(_S, D) ->
?NEW_LEAF(D).
-ifdef(EUNIT).
map_test_() ->
N0 = ?LEAFSIZE,
Id = fun (_,X) -> X end,
Plus = fun(N) -> fun (_,X) -> X+N end end,
Default = fun(_K,undefined) -> no_value;
(K,V) -> K+V
end,
[?_assertError(badarg, map([], new())),
?_assertError(badarg, map([], new(10))),
?_assert(to_list(map(Id, new())) =:= []),
?_assert(to_list(map(Id, new(1))) =:= [undefined]),
?_assert(to_list(map(Id, new(5,{default,0}))) =:= [0,0,0,0,0]),
?_assert(to_list(map(Id, from_list([1,2,3,4]))) =:= [1,2,3,4]),
?_assert(to_list(map(Plus(1), from_list([0,1,2,3]))) =:= [1,2,3,4]),
?_assert(to_list(map(Plus(-1), from_list(lists:seq(1,11))))
=:= lists:seq(0,10)),
?_assert(to_list(map(Plus(11), from_list(lists:seq(0,99999))))
=:= lists:seq(11,100010)),
?_assert([{0,0},{N0*2+1,N0*2+1+1},{N0*100+1,N0*100+1+2}] =:=
sparse_to_orddict((map(Default,
set(N0*100+1,2,
set(N0*2+1,1,
set(0,0,new())))))#array{default = no_value}))
].
-endif.
%% Function = (Index::integer(), Value::term()) -> term()
%% @doc Map the given function onto each element of the array, skipping
%% default-valued entries. The elements are visited in order from the
%% lowest index to the highest. If `Function' is not a function, the
%% call fails with reason `badarg'.
%%
%% @see map/2
-spec sparse_map(Function, Array :: array(Type1)) -> array(Type2) when
Function :: fun((Index :: array_indx(), Type1) -> Type2).
sparse_map(Function, Array=#array{size = N, elements = E, default = D})
when is_function(Function, 2) ->
if N > 0 ->
A = Array#array{elements = []}, % kill reference, for GC
A#array{elements = sparse_map_1(N-1, E, 0, Function, D)};
true ->
Array
end;
sparse_map(_, _) ->
erlang:error(badarg).
%% see map/2 for details
%% TODO: we can probably optimize away the use of div/rem here
sparse_map_1(N, E=?NODEPATTERN(S), Ix, F, D) ->
list_to_tuple(lists:reverse([S | sparse_map_2(1, E, Ix, F, D, [],
N div S + 1,
N rem S, S)]));
sparse_map_1(_N, E, _Ix, _F, _D) when is_integer(E) ->
E;
sparse_map_1(_N, E, Ix, F, D) ->
list_to_tuple(lists:reverse(sparse_map_3(1, E, Ix, F, D, []))).
sparse_map_2(I, E, Ix, F, D, L, I, R, _S) ->
sparse_map_2_1(I+1, E,
[sparse_map_1(R, element(I, E), Ix, F, D) | L]);
sparse_map_2(I, E, Ix, F, D, L, N, R, S) ->
sparse_map_2(I+1, E, Ix + S, F, D,
[sparse_map_1(S-1, element(I, E), Ix, F, D) | L],
N, R, S).
sparse_map_2_1(I, E, L) when I =< ?NODESIZE ->
sparse_map_2_1(I+1, E, [element(I, E) | L]);
sparse_map_2_1(_I, _E, L) ->
L.
-spec sparse_map_3(pos_integer(), _, array_indx(),
fun((array_indx(),_) -> _), _, [X]) -> [X].
sparse_map_3(I, T, Ix, F, D, L) when I =< ?LEAFSIZE ->
case element(I, T) of
D -> sparse_map_3(I+1, T, Ix+1, F, D, [D | L]);
E -> sparse_map_3(I+1, T, Ix+1, F, D, [F(Ix, E) | L])
end;
sparse_map_3(_I, _E, _Ix, _F, _D, L) ->
L.
-ifdef(EUNIT).
sparse_map_test_() ->
N0 = ?LEAFSIZE,
Id = fun (_,X) -> X end,
Plus = fun(N) -> fun (_,X) -> X+N end end,
KeyPlus = fun (K,X) -> K+X end,
[?_assertError(badarg, sparse_map([], new())),
?_assertError(badarg, sparse_map([], new(10))),
?_assert(to_list(sparse_map(Id, new())) =:= []),
?_assert(to_list(sparse_map(Id, new(1))) =:= [undefined]),
?_assert(to_list(sparse_map(Id, new(5,{default,0}))) =:= [0,0,0,0,0]),
?_assert(to_list(sparse_map(Id, from_list([1,2,3,4]))) =:= [1,2,3,4]),
?_assert(to_list(sparse_map(Plus(1), from_list([0,1,2,3])))
=:= [1,2,3,4]),
?_assert(to_list(sparse_map(Plus(-1), from_list(lists:seq(1,11))))
=:= lists:seq(0,10)),
?_assert(to_list(sparse_map(Plus(11), from_list(lists:seq(0,99999))))
=:= lists:seq(11,100010)),
?_assert(to_list(sparse_map(Plus(1), set(1,1,new({default,0}))))
=:= [0,2]),
?_assert(to_list(sparse_map(Plus(1),
set(3,4,set(0,1,new({default,0})))))
=:= [2,0,0,5]),
?_assert(to_list(sparse_map(Plus(1),
set(9,9,set(1,1,new({default,0})))))
=:= [0,2,0,0,0,0,0,0,0,10]),
?_assert([{0,0},{N0*2+1,N0*2+1+1},{N0*100+1,N0*100+1+2}] =:=
sparse_to_orddict(sparse_map(KeyPlus,
set(N0*100+1,2,
set(N0*2+1,1,
set(0,0,new()))))))
].
-endif.
%% @doc Fold the elements of the array using the given function and
%% initial accumulator value. The elements are visited in order from the
%% lowest index to the highest. If `Function' is not a function, the
%% call fails with reason `badarg'.
%%
%% @see foldr/3
%% @see map/2
%% @see sparse_foldl/3
-spec foldl(Function, InitialAcc :: A, Array :: array(Type)) -> B when
Function :: fun((Index :: array_indx(), Value :: Type, Acc :: A) -> B).
foldl(Function, A, #array{size = N, elements = E, default = D})
when is_function(Function, 3) ->
if N > 0 ->
foldl_1(N-1, E, A, 0, Function, D);
true ->
A
end;
foldl(_, _, _) ->
erlang:error(badarg).
foldl_1(N, E=?NODEPATTERN(S), A, Ix, F, D) ->
foldl_2(1, E, A, Ix, F, D, N div S + 1, N rem S, S);
foldl_1(N, E, A, Ix, F, D) when is_integer(E) ->
foldl_1(N, unfold(E, D), A, Ix, F, D);
foldl_1(N, E, A, Ix, F, _D) ->
foldl_3(1, E, A, Ix, F, N+1).
foldl_2(I, E, A, Ix, F, D, I, R, _S) ->
foldl_1(R, element(I, E), A, Ix, F, D);
foldl_2(I, E, A, Ix, F, D, N, R, S) ->
foldl_2(I+1, E, foldl_1(S-1, element(I, E), A, Ix, F, D),
Ix + S, F, D, N, R, S).
-spec foldl_3(pos_integer(), _, A, array_indx(),
fun((array_indx, _, A) -> B), integer()) -> B.
foldl_3(I, E, A, Ix, F, N) when I =< N ->
foldl_3(I+1, E, F(Ix, element(I, E), A), Ix+1, F, N);
foldl_3(_I, _E, A, _Ix, _F, _N) ->
A.
-ifdef(EUNIT).
foldl_test_() ->
N0 = ?LEAFSIZE,
Count = fun (_,_,N) -> N+1 end,
Sum = fun (_,X,N) -> N+X end,
Reverse = fun (_,X,L) -> [X|L] end,
Vals = fun(_K,undefined,{C,L}) -> {C+1,L};
(K,X,{C,L}) -> {C,[K+X|L]}
end,
[?_assertError(badarg, foldl([], 0, new())),
?_assertError(badarg, foldl([], 0, new(10))),
?_assert(foldl(Count, 0, new()) =:= 0),
?_assert(foldl(Count, 0, new(1)) =:= 1),
?_assert(foldl(Count, 0, new(10)) =:= 10),
?_assert(foldl(Count, 0, from_list([1,2,3,4])) =:= 4),
?_assert(foldl(Count, 10, from_list([0,1,2,3,4,5,6,7,8,9])) =:= 20),
?_assert(foldl(Count, 1000, from_list(lists:seq(0,999))) =:= 2000),
?_assert(foldl(Sum, 0, from_list(lists:seq(0,10))) =:= 55),
?_assert(foldl(Reverse, [], from_list(lists:seq(0,1000)))
=:= lists:reverse(lists:seq(0,1000))),
?_assert({999,[N0*100+1+2,N0*2+1+1,0]} =:=
foldl(Vals, {0,[]},
set(N0*100+1,2,
set(N0*2+1,1,
set(0,0,new())))))
].
-endif.
%% @doc Fold the elements of the array using the given function and
%% initial accumulator value, skipping default-valued entries. The
%% elements are visited in order from the lowest index to the highest.
%% If `Function' is not a function, the call fails with reason `badarg'.
%%
%% @see foldl/3
%% @see sparse_foldr/3
-spec sparse_foldl(Function, InitialAcc :: A, Array :: array(Type)) -> B when
Function :: fun((Index :: array_indx(), Value :: Type, Acc :: A) -> B).
sparse_foldl(Function, A, #array{size = N, elements = E, default = D})
when is_function(Function, 3) ->
if N > 0 ->
sparse_foldl_1(N-1, E, A, 0, Function, D);
true ->
A
end;
sparse_foldl(_, _, _) ->
erlang:error(badarg).
%% see foldl/3 for details
%% TODO: this can be optimized
sparse_foldl_1(N, E=?NODEPATTERN(S), A, Ix, F, D) ->
sparse_foldl_2(1, E, A, Ix, F, D, N div S + 1, N rem S, S);
sparse_foldl_1(_N, E, A, _Ix, _F, _D) when is_integer(E) ->
A;
sparse_foldl_1(N, E, A, Ix, F, D) ->
sparse_foldl_3(1, E, A, Ix, F, D, N+1).
sparse_foldl_2(I, E, A, Ix, F, D, I, R, _S) ->
sparse_foldl_1(R, element(I, E), A, Ix, F, D);
sparse_foldl_2(I, E, A, Ix, F, D, N, R, S) ->
sparse_foldl_2(I+1, E, sparse_foldl_1(S-1, element(I, E), A, Ix, F, D),
Ix + S, F, D, N, R, S).
sparse_foldl_3(I, T, A, Ix, F, D, N) when I =< N ->
case element(I, T) of
D -> sparse_foldl_3(I+1, T, A, Ix+1, F, D, N);
E -> sparse_foldl_3(I+1, T, F(Ix, E, A), Ix+1, F, D, N)
end;
sparse_foldl_3(_I, _T, A, _Ix, _F, _D, _N) ->
A.
-ifdef(EUNIT).
sparse_foldl_test_() ->
N0 = ?LEAFSIZE,
Count = fun (_,_,N) -> N+1 end,
Sum = fun (_,X,N) -> N+X end,
Reverse = fun (_,X,L) -> [X|L] end,
Vals = fun(_K,undefined,{C,L}) -> {C+1,L};
(K,X,{C,L}) -> {C,[K+X|L]}
end,
[?_assertError(badarg, sparse_foldl([], 0, new())),
?_assertError(badarg, sparse_foldl([], 0, new(10))),
?_assert(sparse_foldl(Count, 0, new()) =:= 0),
?_assert(sparse_foldl(Count, 0, new(1)) =:= 0),
?_assert(sparse_foldl(Count, 0, new(10,{default,1})) =:= 0),
?_assert(sparse_foldl(Count, 0, from_list([0,1,2,3,4],0)) =:= 4),
?_assert(sparse_foldl(Count, 0, from_list([0,1,2,3,4,5,6,7,8,9,0],0))
=:= 9),
?_assert(sparse_foldl(Count, 0, from_list(lists:seq(0,999),0))
=:= 999),
?_assert(sparse_foldl(Sum, 0, from_list(lists:seq(0,10), 5)) =:= 50),
?_assert(sparse_foldl(Reverse, [], from_list(lists:seq(0,1000), 0))
=:= lists:reverse(lists:seq(1,1000))),
?_assert({0,[N0*100+1+2,N0*2+1+1,0]} =:=
sparse_foldl(Vals, {0,[]},
set(N0*100+1,2,
set(N0*2+1,1,
set(0,0,new())))))
].
-endif.
%% @doc Fold the elements of the array right-to-left using the given
%% function and initial accumulator value. The elements are visited in
%% order from the highest index to the lowest. If `Function' is not a
%% function, the call fails with reason `badarg'.
%%
%% @see foldl/3
%% @see map/2
-spec foldr(Function, InitialAcc :: A, Array :: array(Type)) -> B when
Function :: fun((Index :: array_indx(), Value :: Type, Acc :: A) -> B).
foldr(Function, A, #array{size = N, elements = E, default = D})
when is_function(Function, 3) ->
if N > 0 ->
I = N - 1,
foldr_1(I, E, I, A, Function, D);
true ->
A
end;
foldr(_, _, _) ->
erlang:error(badarg).
%% this is based on to_orddict/1
foldr_1(I, E=?NODEPATTERN(S), Ix, A, F, D) ->
foldr_2(I div S + 1, E, Ix, A, F, D, I rem S, S-1);
foldr_1(I, E, Ix, A, F, D) when is_integer(E) ->
foldr_1(I, unfold(E, D), Ix, A, F, D);
foldr_1(I, E, Ix, A, F, _D) ->
I1 = I+1,
foldr_3(I1, E, Ix-I1, A, F).
foldr_2(0, _E, _Ix, A, _F, _D, _R, _R0) ->
A;
foldr_2(I, E, Ix, A, F, D, R, R0) ->
foldr_2(I-1, E, Ix - R - 1,
foldr_1(R, element(I, E), Ix, A, F, D),
F, D, R0, R0).
-spec foldr_3(array_indx(), term(), integer(), A,
fun((array_indx(), _, A) -> B)) -> B.
foldr_3(0, _E, _Ix, A, _F) ->
A;
foldr_3(I, E, Ix, A, F) ->
foldr_3(I-1, E, Ix, F(Ix+I, element(I, E), A), F).
-ifdef(EUNIT).
foldr_test_() ->
N0 = ?LEAFSIZE,
Count = fun (_,_,N) -> N+1 end,
Sum = fun (_,X,N) -> N+X end,
List = fun (_,X,L) -> [X|L] end,
Vals = fun(_K,undefined,{C,L}) -> {C+1,L};
(K,X,{C,L}) -> {C,[K+X|L]}
end,
[?_assertError(badarg, foldr([], 0, new())),
?_assertError(badarg, foldr([], 0, new(10))),
?_assert(foldr(Count, 0, new()) =:= 0),
?_assert(foldr(Count, 0, new(1)) =:= 1),
?_assert(foldr(Count, 0, new(10)) =:= 10),
?_assert(foldr(Count, 0, from_list([1,2,3,4])) =:= 4),
?_assert(foldr(Count, 10, from_list([0,1,2,3,4,5,6,7,8,9])) =:= 20),
?_assert(foldr(Count, 1000, from_list(lists:seq(0,999))) =:= 2000),
?_assert(foldr(Sum, 0, from_list(lists:seq(0,10))) =:= 55),
?_assert(foldr(List, [], from_list(lists:seq(0,1000)))
=:= lists:seq(0,1000)),
?_assert({999,[0,N0*2+1+1,N0*100+1+2]} =:=
foldr(Vals, {0,[]},
set(N0*100+1,2,
set(N0*2+1,1,
set(0,0,new())))))
].
-endif.
%% @doc Fold the elements of the array right-to-left using the given
%% function and initial accumulator value, skipping default-valued
%% entries. The elements are visited in order from the highest index to
%% the lowest. If `Function' is not a function, the call fails with
%% reason `badarg'.
%%
%% @see foldr/3
%% @see sparse_foldl/3
-spec sparse_foldr(Function, InitialAcc :: A, Array :: array(Type)) -> B when
Function :: fun((Index :: array_indx(), Value :: Type, Acc :: A) -> B).
sparse_foldr(Function, A, #array{size = N, elements = E, default = D})
when is_function(Function, 3) ->
if N > 0 ->
I = N - 1,
sparse_foldr_1(I, E, I, A, Function, D);
true ->
A
end;
sparse_foldr(_, _, _) ->
erlang:error(badarg).
%% see foldr/3 for details
%% TODO: this can be optimized
sparse_foldr_1(I, E=?NODEPATTERN(S), Ix, A, F, D) ->
sparse_foldr_2(I div S + 1, E, Ix, A, F, D, I rem S, S-1);
sparse_foldr_1(_I, E, _Ix, A, _F, _D) when is_integer(E) ->
A;
sparse_foldr_1(I, E, Ix, A, F, D) ->
I1 = I+1,
sparse_foldr_3(I1, E, Ix-I1, A, F, D).
sparse_foldr_2(0, _E, _Ix, A, _F, _D, _R, _R0) ->
A;
sparse_foldr_2(I, E, Ix, A, F, D, R, R0) ->
sparse_foldr_2(I-1, E, Ix - R - 1,
sparse_foldr_1(R, element(I, E), Ix, A, F, D),
F, D, R0, R0).
-spec sparse_foldr_3(array_indx(), _, array_indx(), A,
fun((array_indx(), _, A) -> B), _) -> B.
sparse_foldr_3(0, _T, _Ix, A, _F, _D) ->
A;
sparse_foldr_3(I, T, Ix, A, F, D) ->
case element(I, T) of
D -> sparse_foldr_3(I-1, T, Ix, A, F, D);
E -> sparse_foldr_3(I-1, T, Ix, F(Ix+I, E, A), F, D)
end.
%% @doc Get the number of entries in the array up until the last
%% non-default valued entry. In other words, returns `I+1' if `I' is the
%% last non-default valued entry in the array, or zero if no such entry
%% exists.
%% @see size/1
%% @see resize/1
-spec sparse_size(Array :: array()) -> non_neg_integer().
sparse_size(A) ->
F = fun (I, _V, _A) -> throw({value, I}) end,
try sparse_foldr(F, [], A) of
[] -> 0
catch
{value, I} ->
I + 1
end.
-ifdef(EUNIT).
sparse_foldr_test_() ->
N0 = ?LEAFSIZE,
Count = fun (_,_,N) -> N+1 end,
Sum = fun (_,X,N) -> N+X end,
List = fun (_,X,L) -> [X|L] end,
Vals = fun(_K,undefined,{C,L}) -> {C+1,L};
(K,X,{C,L}) -> {C,[K+X|L]}
end,
[?_assertError(badarg, sparse_foldr([], 0, new())),
?_assertError(badarg, sparse_foldr([], 0, new(10))),
?_assert(sparse_foldr(Count, 0, new()) =:= 0),
?_assert(sparse_foldr(Count, 0, new(1)) =:= 0),
?_assert(sparse_foldr(Count, 0, new(10,{default,1})) =:= 0),
?_assert(sparse_foldr(Count, 0, from_list([0,1,2,3,4],0)) =:= 4),
?_assert(sparse_foldr(Count, 0, from_list([0,1,2,3,4,5,6,7,8,9,0],0))
=:= 9),
?_assert(sparse_foldr(Count, 0, from_list(lists:seq(0,999),0))
=:= 999),
?_assert(sparse_foldr(Sum, 0, from_list(lists:seq(0,10),5)) =:= 50),
?_assert(sparse_foldr(List, [], from_list(lists:seq(0,1000),0))
=:= lists:seq(1,1000)),
?_assert(sparse_size(new()) =:= 0),
?_assert(sparse_size(new(8)) =:= 0),
?_assert(sparse_size(array:set(7, 0, new())) =:= 8),
?_assert(sparse_size(array:set(7, 0, new(10))) =:= 8),
?_assert(sparse_size(array:set(99, 0, new(10,{fixed,false})))
=:= 100),
?_assert(sparse_size(array:set(7, undefined, new())) =:= 0),
?_assert(sparse_size(array:from_list([1,2,3,undefined])) =:= 3),
?_assert(sparse_size(array:from_orddict([{3,0},{17,0},{99,undefined}]))
=:= 18),
?_assert({0,[0,N0*2+1+1,N0*100+1+2]} =:=
sparse_foldr(Vals, {0,[]},
set(N0*100+1,2,
set(N0*2+1,1,
set(0,0,new())))))
].
-endif.
