ft: 模板添加

src/template/utDBLoad.erl

@@ -0,0 +1,47 @@
+-module(utDBLoad).
+
+-export([loadData/1]).
+
+%%-----------------------------------------------------------------
+%% load_data/1
+%% @doc 起服的时候 加载数据
+%% ```
+%%
+%% '''
+%% @end
+%% -----------------------------------------------------------------
+-spec loadData(non_neg_integer()) -> no_return().
+%% -----------------------------------------------------------------
+% #方式4 仅仅使用 id<max and limit size;
+% #每次查询前获取上一页最小id作为下一页的最大id使用
+% ##20万-40万:82959503-82620566  60万-80万:82334851   260万-280万:80106996-79887685 660万-680万:76010656-75810657 1660万-1680万:53482458-53240959 3660万-3680万:32532145-32332146
+% #首页查询
+% select * from order_table order by id desc limit 200000;
+% #非首页查询
+% #平均耗时：1.539s
+% select * from order_table where id <=82543981 order by id desc limit 200000;
+loadData(Limit) ->
+   ValueList = db:reads_mysql(dbTableName, [], [{key_id, desc}], [Limit]),
+   NextId = dealValueList(ValueList, Limit, 0, 0),
+   loadLeft(NextId, Limit).
+
+loadLeft(0, _Limit) ->
+   ok;
+loadLeft(NextId, Limit) ->
+   ValueList = db:reads_mysql(dbTableName, [{key_id, "<", NextId}], [{key_id, desc}], [Limit]),
+   NewNextId = dealValueList(ValueList, Limit, 0, 0),
+   loadLeft(NewNextId, Limit).
+
+dealValueList([], Limit, SumCnt, NextId) ->
+   case SumCnt >= Limit of
+      true ->
+         NextId;
+      _ ->
+         0
+   end;
+dealValueList([OneInfo | AllyList], Limit, SumCnt, _NextId) ->
+   NewNextId = parseData(OneInfo),
+   dealValueList(AllyList, Limit, SumCnt + 1, NewNextId).
+
+parseData(OneInfo) ->
+   _NewNextId = element(1, OneInfo).

src/template/utEtsFold.erl

@@ -0,0 +1,91 @@
+-module(utEtsFold).
+
+%% 请注意，对于表类型ordered_set和由单个 ETS 函数调用(如select/2)完成的遍历(一次调用就返回了全部结果没有Next 迭代器了)，不需要 safe_fixtable/ 2 。
+
+-export([rank/5, fold/2]).
+
+rank(TabId, PageInfo, Page, Limit, TotalCnt) ->
+   %% 遍历所有tab
+   MS =
+      case PageInfo == 0 orelse PageInfo of
+         true ->
+            ets:fun2ms(fun(T) -> T end);
+         "" ->
+            ets:fun2ms(fun(T) -> T end);
+         _ ->
+            try binary_to_term(list_to_binary(PageInfo)) of
+               KeyTerm when KeyTerm == <<"">>; KeyTerm == "" ->
+                  ets:fun2ms(fun(T) -> T end);
+               KeyTerm ->
+                  ets:fun2ms(fun({K, _V} = T) when K < KeyTerm -> T end)
+            catch _C:_R ->
+               ets:fun2ms(fun(T) -> T end)
+            end
+      end,
+
+   case ets:select_reverse(TabId, MS, Limit) of
+      '$end_of_table' ->
+         {true, {<<"">>, []}};
+      {AllyIds, '$end_of_table'} ->
+         {true, makeRankData(AllyIds)};
+      {AllyIds, _NextKey} ->
+         Length = length(AllyIds),
+         if
+            Length < Limit ->
+               {true, makeRankData(AllyIds)};
+            true ->
+               NewCurCnt = Page * Limit + Length,
+               case NewCurCnt >= TotalCnt of
+                  true ->
+                     {true, makeRankData(AllyIds)};
+                  _ ->
+                     {false, makeRankData(AllyIds)}
+               end
+         end
+   end.
+
+makeRankData(AllyIds) ->
+   makeRankData(AllyIds, <<"">>, []).
+
+makeRankData([], LastKey, Acc) ->
+   case LastKey of
+      <<"">> ->
+         {LastKey, lists:reverse(Acc)};
+      _ ->
+         {erlang:term_to_binary(LastKey), lists:reverse(Acc)}
+   end;
+makeRankData([{CurKey, Uuid} | AllyIds], LastKey, Acc) ->
+   case ets:lookup(ets_pub_rank_info, Uuid) of
+      [OneData] ->
+         makeRankData(AllyIds, CurKey, [OneData | Acc]);
+      _ ->
+         makeRankData(AllyIds, LastKey, Acc)
+   end.
+
+
+fold(TabId, Limit) ->
+   ets:safe_fixtable(TabId, true),
+   try
+      case ets:match_object(TabId, '$1', Limit) of
+         '$end_of_table' ->
+            ok;
+         {ValueList, NextKey} ->
+            matchDoFun(ValueList),
+            continueNext(NextKey)
+      end
+   after
+      ets:safe_fixtable(TabId, false)
+   end.
+
+continueNext(NextKey) ->
+   case ets:match_object(NextKey) of
+      '$end_of_table' ->
+         ok;
+      {ValueList, NewNextKey} ->
+         matchDoFun(ValueList),
+         continueNext(NewNextKey)
+   end.
+
+matchDoFun(_ValueList) ->
+   %% do something
+   ok.

src/template/utMapsFold.erl

@@ -0,0 +1,14 @@
+-module(utMapsFold).
+
+-export([fold/1]).
+
+fold(Map) ->
+   fold(maps:iterator(Map), []).
+
+fold(Iterator, AccList) ->
+   case maps:next(Iterator) of
+      {Key, Value, NextIter} ->
+         fold(NextIter, [{Key, Value} | AccList]);
+      none ->
+         AccList
+   end.