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% Licensed under the Apache License, Version 2.0 (the "License"); you may not
% use this file except in compliance with the License. You may obtain a copy of
% the License at
%
% http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
% License for the specific language governing permissions and limitations under
% the License.
-module(couch_ejson_size).
-export([encoded_size/1]).
%% Compound objects
encoded_size({[]}) ->
% opening { and closing }
2;
encoded_size({KVs}) ->
% Would add 2 because opening { and closing }, but then inside the LC
% would accumulate an extra , at the end so subtract 2 - 1
1 + lists:sum([encoded_size(K) + encoded_size(V) + 2 || {K, V} <- KVs]);
encoded_size([]) ->
% opening [ and closing ]
2;
encoded_size(List) when is_list(List) ->
% 2 is for [ and ] but inside LC would accumulate an extra , so subtract
% 2 - 1
1 + lists:sum([encoded_size(V) + 1 || V <- List]);
%% Floats.
encoded_size(0.0) ->
3;
encoded_size(1.0) ->
3;
encoded_size(Float) when is_float(Float), Float < 0.0 ->
encoded_size(-Float) + 1;
encoded_size(Float) when is_float(Float), Float < 1.0 ->
if
% close enough to 0.0
Float =< 1.0e-300 -> 3;
% Xe-YYY
Float =< 1.0e-100 -> 6;
% Xe-YY
Float =< 1.0e-10 -> 5;
% Xe-Y, 0.0X
Float =< 0.01 -> 4;
% 0.X
true -> 3
end;
encoded_size(Float) when is_float(Float) ->
if
% XeYYY
Float >= 1.0e100 -> 5;
% XeYY
Float >= 1.0e10 -> 4;
% XeY, X.Y
true -> 3
end;
%% Integers
encoded_size(0) ->
1;
encoded_size(Integer) when is_integer(Integer), Integer < 0 ->
encoded_size(-Integer) + 1;
encoded_size(Integer) when is_integer(Integer) ->
if
Integer < 10 -> 1;
Integer < 100 -> 2;
Integer < 1000 -> 3;
Integer < 10000 -> 4;
true -> trunc(math:log10(Integer)) + 1
end;
%% Strings
encoded_size(Binary) when is_binary(Binary) ->
2 + byte_size(Binary);
%% Special terminal symbols as atoms
encoded_size(null) ->
4;
encoded_size(true) ->
4;
encoded_size(false) ->
5;
%% Other atoms
encoded_size(Atom) when is_atom(Atom) ->
encoded_size(atom_to_binary(Atom, utf8)).
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