80 lines
2.5 KiB
Erlang
80 lines
2.5 KiB
Erlang
%%--------------------------------------------------------------------
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%% Copyright (c) 2019-2021 EMQ Technologies Co., Ltd. All Rights Reserved.
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%%
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%% Licensed under the Apache License, Version 2.0 (the "License");
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%% you may not use this file except in compliance with the License.
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%% You may obtain a copy of the License at
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%%
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%% http://www.apache.org/licenses/LICENSE-2.0
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%%
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%% Unless required by applicable law or agreed to in writing, software
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%% distributed under the License is distributed on an "AS IS" BASIS,
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%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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%% See the License for the specific language governing permissions and
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%% limitations under the License.
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%%--------------------------------------------------------------------
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%% a simple decimal module for rate-related calculations
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-module(emqx_limiter_decimal).
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%% API
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-export([ add/2, sub/2, mul/2
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, add_to_counter/3, put_to_counter/3]).
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-export_type([decimal/0, zero_or_float/0]).
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-type decimal() :: infinity | number().
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-type zero_or_float() :: 0 | float().
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%%--------------------------------------------------------------------
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%%% API
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%%--------------------------------------------------------------------
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-spec add(decimal(), decimal()) -> decimal().
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add(A, B) when A =:= infinity
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orelse B =:= infinity ->
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infinity;
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add(A, B) ->
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A + B.
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-spec sub(decimal(), decimal()) -> decimal().
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sub(A, B) when A =:= infinity
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orelse B =:= infinity ->
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infinity;
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sub(A, B) ->
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A - B.
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-spec mul(decimal(), decimal()) -> decimal().
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mul(A, B) when A =:= infinity
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orelse B =:= infinity ->
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infinity;
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mul(A, B) ->
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A * B.
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-spec add_to_counter(counters:counters_ref(), pos_integer(), decimal()) ->
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{zero_or_float(), zero_or_float()}.
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add_to_counter(_, _, infinity) ->
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{0, 0};
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add_to_counter(Counter, Index, Val) when is_float(Val) ->
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IntPart = erlang:floor(Val),
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if IntPart > 0 ->
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counters:add(Counter, Index, IntPart);
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true ->
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ok
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end,
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{IntPart, Val - IntPart};
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add_to_counter(Counter, Index, Val) ->
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counters:add(Counter, Index, Val),
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{Val, 0}.
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-spec put_to_counter(counters:counters_ref(), pos_integer(), decimal()) -> ok.
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put_to_counter(_, _, infinity) ->
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ok;
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put_to_counter(Counter, Index, Val) when is_float(Val) ->
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IntPart = erlang:floor(Val),
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counters:put(Counter, Index, IntPart);
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put_to_counter(Counter, Index, Val) ->
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counters:put(Counter, Index, Val).
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