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Contents
-module(example).
-export( [create/1, read/1, size/1, write/2, write_attempt/2, test_version/0] ).
create( Size ) -> erlang:spawn( fun() -> loop( 0, Size, queue:new() ) end ).
read( Pid ) -> request( Pid, read ).
size( Pid ) -> request( Pid, size ).
write( Pid, Item ) -> Pid ! {write, Item}.
write_attempt( Pid, Item ) ->
Pid ! {write_attempt, Item, erlang:self()},
receive
{write_attempt, true, Pid} -> ok;
{write_attempt, false, Pid} -> {error, full}
end.
loop( Current_size, Max_size, Queue ) ->
receive
{read, Pid} ->
{Result, New_queue} = queue:out( Queue ),
Pid ! {read, Result, erlang:self()},
loop( Current_size - 1, Max_size, New_queue );
{size, Pid} ->
Pid ! {size, Max_size, erlang:self()},
loop( Current_size, Max_size, Queue );
{write, Item} ->
{New_size, New_queue} = write( Current_size, Max_size, Item, Queue ),
loop( New_size, Max_size, New_queue );
{write_attempt, Item, Pid} ->
Pid ! {write_attempt, Current_size < Max_size, erlang:self()},
{New_size, New_queue} = write_attempt( Current_size, Max_size, Item, Queue ),
loop( New_size, Max_size, New_queue )
end.
request( Pid, Request ) ->
Pid ! {Request, erlang:self()},
receive
{Request, empty, Pid} -> {error, empty};
{Request, {value, Answer}, Pid} -> {ok, Answer};
{Request, Answer, Pid} -> {ok, Answer}
end.
write( Current, Max, Item, Queue ) when Current < Max ->
{Current + 1, queue:in( Item, Queue )};
write( Max, Max, Item, Queue ) ->
{_Old, New_queue} = queue:out( Queue ),
{Max, queue:in( Item, New_queue )}.
write_attempt( Max, Max, _Item, Queue ) -> {Max, Queue};
write_attempt( Current, Max, Item, Queue ) -> write( Current, Max, Item, Queue ).
test_version() ->
1.
Version data entries
310 entries across 310 versions & 1 rubygems