erlang crc32 hash 算法 使用 put get

gistfile1.erl

-module(erichash).
-export([start/2, getTargetInfo/1]).
-define(HOST_LIST_ETS_NAME , hostlist).
-define(PROCESS_LIST_NAME , pl).

start(HostList , Num) when is_list(HostList), is_integer(Num) ->
    erase(?PROCESS_LIST_NAME),
    targets(HostList, Num),
    self().

targets(HostList , Renum) when is_list(HostList) ->
    CrcList = lists:map(fun({Key, Info}) ->
                            NewList = createKey(Renum, Key, []),
                            [{erlang:crc32(NewKey), Key, Info} || NewKey <- NewList]
                            end,
                        HostList),
    setHostCache_processlist(lists:ukeysort(1, lists:merge(CrcList))).

%
% use process list saving HostList
% putkey,Info    get(key)
%

setHostCache_processlist(HostList) when is_list(HostList) ->
    case get(?PROCESS_LIST_NAME) of
        undefined ->
            put(?PROCESS_LIST_NAME, HostList);
        Info ->
            Info
    end.
           
%
% use ets saving HostList
%

%setHostCache_ets(HostList) when is_list(HostList) ->
%   CacheId = ets:new(?HOST_LIST_ETS_NAME, [ordered_set,public,named_table]),
%   [ets:insert(CacheId, Info) || Info <- HostList],
%    ets:tab2list(?HOST_LIST_ETS_NAME).
   

getTargetInfo(UserKey) when is_list(UserKey) ->
    %using ets for geting HostList
    %HostList = ets:tab2list(?HOST_LIST_ETS_NAME),
    %using process list for geting HostList
    HostList = get(?PROCESS_LIST_NAME), 
    try getHostInfo(HostList, UserKey) of  
         NewList ->
            if
                length(NewList) >= 1 ->
                    [H|_] = NewList,
                    {ok, H};
                true ->
                    [H|_] = HostList,
                    {ok, H}
            end
    catch
            _:_ ->
            [H|_] = HostList,
            {ok, H}
    end.

getHostInfo(HostList, UserKey)  ->
    [{Num, Key, Info} || {Num , Key , Info} <- HostList , Num >= erlang:crc32(UserKey) ].

createKey(0, Key, NewList) when is_list(Key), is_list(NewList) ->
    NewList++[Key++"0"];

createKey(Num, Key, NewList) when is_list(Key), is_list(NewList), is_integer(Num) ->
    NumTem = erlang:abs(Num),
    createKey(NumTem-1, Key, NewList++[Key++integer_to_list(NumTem)]).