57 lines
2.0 KiB
Erlang
57 lines
2.0 KiB
Erlang
%% Copyright (C) 2026 Fluxer Contributors
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%%
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%% This file is part of Fluxer.
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%%
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%% Fluxer is free software: you can redistribute it and/or modify
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%% it under the terms of the GNU Affero General Public License as published by
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%% the Free Software Foundation, either version 3 of the License, or
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%% (at your option) any later version.
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%%
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%% Fluxer is distributed in the hope that it will be useful,
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%% but WITHOUT ANY WARRANTY; without even the implied warranty of
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%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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%% GNU Affero General Public License for more details.
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%%
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%% You should have received a copy of the GNU Affero General Public License
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%% along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
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-module(snowflake_util).
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-export([extract_timestamp/1]).
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-define(FLUXER_EPOCH, 1420070400000).
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-define(TIMESTAMP_SHIFT, 22).
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-spec extract_timestamp(binary() | integer()) -> integer().
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extract_timestamp(SnowflakeBin) when is_binary(SnowflakeBin) ->
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Snowflake = binary_to_integer(SnowflakeBin),
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extract_timestamp(Snowflake);
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extract_timestamp(Snowflake) when is_integer(Snowflake) ->
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(Snowflake bsr ?TIMESTAMP_SHIFT) + ?FLUXER_EPOCH.
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-ifdef(TEST).
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-include_lib("eunit/include/eunit.hrl").
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extract_timestamp_from_integer_test() ->
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Timestamp = 1704067200000,
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RelativeTs = Timestamp - ?FLUXER_EPOCH,
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Snowflake = RelativeTs bsl ?TIMESTAMP_SHIFT,
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?assertEqual(Timestamp, extract_timestamp(Snowflake)).
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extract_timestamp_from_binary_test() ->
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Timestamp = 1704067200000,
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RelativeTs = Timestamp - ?FLUXER_EPOCH,
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Snowflake = RelativeTs bsl ?TIMESTAMP_SHIFT,
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SnowflakeBin = integer_to_binary(Snowflake),
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?assertEqual(Timestamp, extract_timestamp(SnowflakeBin)).
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extract_timestamp_with_worker_and_sequence_test() ->
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Timestamp = 1704067200000,
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RelativeTs = Timestamp - ?FLUXER_EPOCH,
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WorkerId = 5,
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Sequence = 100,
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Snowflake = (RelativeTs bsl ?TIMESTAMP_SHIFT) bor (WorkerId bsl 12) bor Sequence,
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?assertEqual(Timestamp, extract_timestamp(Snowflake)).
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-endif.
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