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811 | -- --
-- package Copyright (c) Dmitry A. Kazakov --
-- Synchronization.Interprocess. Luebeck --
-- Generic_FIFO Spring, 2018 --
-- Implementation --
-- Last revision : 19:18 30 Apr 2018 --
-- --
-- This library is free software; you can redistribute it and/or --
-- modify it under the terms of the GNU General Public License as --
-- published by the Free Software Foundation; either version 2 of --
-- the License, or (at your option) any later version. This library --
-- is distributed in the hope that it will be useful, but WITHOUT --
-- ANY WARRANTY; without even the implied warranty of --
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU --
-- General Public License for more details. You should have --
-- received a copy of the GNU General Public License along with --
-- this library; if not, write to the Free Software Foundation, --
-- Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from --
-- this unit, or you link this unit with other files to produce an --
-- executable, this unit does not by itself cause the resulting --
-- executable to be covered by the GNU General Public License. This --
-- exception does not however invalidate any other reasons why the --
-- executable file might be covered by the GNU Public License. --
--____________________________________________________________________--
with Ada.Calendar; use Ada.Calendar;
with Ada.Exceptions; use Ada.Exceptions;
with Ada.IO_Exceptions; use Ada.IO_Exceptions;
with Ada.Tags; use Ada.Tags;
package body Synchronization.Interprocess.Generic_FIFO is
In_End_Init : constant String := "The in-end of the queue is " &
"not initialized or already " &
"finalized";
Out_End_Init : constant String := "The out-end of the queue is " &
"not initialized or already " &
"finalized";
Queue_Init : constant String := "The queue is " &
"not initialized or already " &
"finalized";
procedure Delete_Implementation
( Queue : in out FIFO'Class;
Count : Natural := 1;
Timeout : Duration := Duration'Last
) is
begin
if Queue.Data = null then
Raise_Exception (Status_Error'Identity, Out_End_Init);
end if;
if Count > 0 then
declare
Free : Positive renames Queue.Data.Free;
First : Positive renames Queue.Data.First;
Buffer : Element_Array renames Queue.Data.Buffer;
Length : Integer := Free - First;
begin
if Length < 0 then
Length := Length + Queue.Size;
end if;
declare
Next : constant Positive :=
First + Integer'Min (Length, Count);
begin
if Next > Queue.Size then
First := Next - Queue.Size;
else
First := Next;
end if;
end;
if Length = Queue.Size - 1 then
Signal (Queue.Not_Full.all); -- Queue was full
end if;
end;
end if;
end Delete_Implementation;
procedure Delete
( Queue : in out FIFO_Out;
Count : Natural := 1;
Timeout : Duration := Duration'Last
) is
begin
Delete_Implementation (Queue, Count, Timeout);
end Delete;
procedure Delete
( Queue : in out Universal_FIFO;
Count : Natural := 1;
Timeout : Duration := Duration'Last
) is
begin
if Queue.Mode = Out_End then
Delete_Implementation (Queue, Count, Timeout);
else
Raise_Exception
( Mode_Error'Identity,
"An in-end of the queue is expected in Delete"
);
end if;
end Delete;
function Get_Implementation
( Queue : FIFO'Class;
Timeout : Duration := Duration'Last
) return Element_Type is
Started : constant Time := Clock;
begin
if Queue.Data = null then
Raise_Exception (Status_Error'Identity, Out_End_Init);
end if;
declare
Free : Positive renames Queue.Data.Free;
First : Positive renames Queue.Data.First;
Buffer : Element_Array renames Queue.Data.Buffer;
begin
loop
if First /= Free then -- Queue is not empty
declare
Element : constant Element_Type := Buffer (First);
begin
if First = Queue.Size then
First := 1;
else
First := First + 1;
end if;
Signal (Queue.Not_Full.all);
return Element;
end;
end if;
Reset (Queue.Not_Empty.all); -- Prepare to wait
if First = Free then -- Still empty, wait
Wait
( Queue.Not_Empty.all,
Timeout - (Clock - Started)
);
end if;
end loop;
end;
end Get_Implementation;
function Get
( Queue : FIFO_Out;
Timeout : Duration := Duration'Last
) return Element_Type is
begin
return Get_Implementation (Queue, Timeout);
end Get;
function Get
( Queue : Universal_FIFO;
Timeout : Duration := Duration'Last
) return Element_Type is
begin
if Queue.Mode = Out_End then
return Get_Implementation (Queue, Timeout);
else
Raise_Exception
( Mode_Error'Identity,
"An out-end of the queue is expected in Get"
);
end if;
end Get;
function Get_Mode (Queue : Universal_FIFO) return FIFO_End is
begin
return Queue.Mode;
end Get_Mode;
function Get_Signature (Object : FIFO) return Unsigned_16 is
begin
return Get_Signature (External_Tag (FIFO'Tag));
end Get_Signature;
function Get_Size (Queue : FIFO) return Storage_Count is
subtype Data is FIFO_Data (Queue.Size);
begin
return Round (Data'Max_Size_In_Storage_Elements);
end Get_Size;
function Is_Empty (Queue : FIFO) return Boolean is
begin
declare
Data : FIFO_Data renames Queue.Data.all;
begin
return Data.First = Data.Free;
end;
exception
when Constraint_Error =>
if Queue.Data = null then
Raise_Exception (Status_Error'Identity, Queue_Init);
else
raise;
end if;
end Is_Empty;
function Is_Full (Queue : FIFO) return Boolean is
begin
declare
Data : FIFO_Data renames Queue.Data.all;
Count : constant Integer := Data.First - Data.Free;
begin
return Count = 1 or else Count = 1 - Data.Size;
end;
exception
when Constraint_Error =>
if Queue.Data = null then
Raise_Exception (Status_Error'Identity, Queue_Init);
else
raise;
end if;
end Is_Full;
function Is_Preserved (Queue : FIFO; Element : Element_Type)
return Boolean is
begin
return True;
end Is_Preserved;
procedure Map
( Queue : in out FIFO;
Shared : in out Abstract_Shared_Environment'Class;
Location : System.Address;
Size : Storage_Count;
Owner : Boolean
) is
subtype Data is FIFO_Data (Queue.Size);
package Mapper is new Generic_Memory_Mapper (Data);
This : Abstract_Shared_Object_Ptr := Shared.First;
begin
while This /= null and then This /= Queue'Unchecked_Access loop
if This.all in Event'Class then
Queue.Not_Full := Queue.Not_Empty;
Queue.Not_Empty := Event'Class (This.all)'Unchecked_Access;
end if;
This := This.Next;
end loop;
if Queue.Not_Full = null then
Raise_Exception
( Mode_Error'Identity,
( "The environment contains no not-full event "
& "record member appearing before the FIFO object"
) );
end if;
Queue.Data := Mapper.Map (Location, Owner).all'Unchecked_Access;
end Map;
procedure Map
( Queue : in out FIFO_In;
Shared : in out Abstract_Shared_Environment'Class;
Location : System.Address;
Size : Storage_Count;
Owner : Boolean
) is
begin
Map (FIFO (Queue), Shared, Location, Size, Owner);
if not Compare_And_Swap
( Target => Queue.Data.Has_In'Access,
Old_Val => 0,
New_Val => 1
)
then
Raise_Exception
( Mode_Error'Identity,
"The queue already has the in-end"
);
end if;
end Map;
procedure Map
( Queue : in out FIFO_Multiplexed_In;
Shared : in out Abstract_Shared_Environment'Class;
Location : System.Address;
Size : Storage_Count;
Owner : Boolean
) is
This : Abstract_Shared_Object_Ptr := Shared.First;
begin
Map (FIFO (Queue), Shared, Location, Size, Owner);
while This /= null and then This /= Queue'Unchecked_Access loop
if This.all in Mutex'Class then
Queue.Lock := Mutex'Class (This.all)'Unchecked_Access;
end if;
This := This.Next;
end loop;
if Queue.Lock = null then
Raise_Exception
( Data_Error'Identity,
( "The environment contains no mutex "
& "record member appearing before the FIFO object"
) );
end if;
if ( not Compare_And_Swap
( Target => Queue.Data.Has_In'Access,
Old_Val => 0,
New_Val => 2
)
and then
not Compare_And_Swap
( Target => Queue.Data.Has_In'Access,
Old_Val => 2,
New_Val => 2
) )
then
Raise_Exception
( Mode_Error'Identity,
"The queue already has an non-multiplexed in-end"
);
end if;
end Map;
procedure Map
( Queue : in out FIFO_Out;
Shared : in out Abstract_Shared_Environment'Class;
Location : System.Address;
Size : Storage_Count;
Owner : Boolean
) is
begin
Map (FIFO (Queue), Shared, Location, Size, Owner);
if not Compare_And_Swap
( Target => Queue.Data.Has_Out'Access,
Old_Val => 0,
New_Val => 1
)
then
Raise_Exception
( Mode_Error'Identity,
"The queue already has the out-end"
);
end if;
end Map;
procedure Map
( Queue : in out Universal_FIFO;
Shared : in out Abstract_Shared_Environment'Class;
Location : System.Address;
Size : Storage_Count;
Owner : Boolean
) is
begin
Map (FIFO (Queue), Shared, Location, Size, Owner);
case Queue.Mode is
when In_End =>
if not Compare_And_Swap
( Target => Queue.Data.Has_In'Access,
Old_Val => 0,
New_Val => 1
)
then
Raise_Exception
( Mode_Error'Identity,
"The queue already has an in-end"
);
end if;
when Multiplexed_In_End =>
declare
This : Abstract_Shared_Object_Ptr := Shared.First;
begin
while ( This /= null
and then
This /= Queue'Unchecked_Access
) loop
if This.all in Mutex'Class then
Queue.Lock :=
Mutex'Class (This.all)'Unchecked_Access;
end if;
This := This.Next;
end loop;
if Queue.Lock = null then
Raise_Exception
( Data_Error'Identity,
( "The environment contains no mutex "
& "record member appearing before the FIFO object"
) );
end if;
if ( not Compare_And_Swap
( Target => Queue.Data.Has_In'Access,
Old_Val => 0,
New_Val => 2
)
and then
not Compare_And_Swap
( Target => Queue.Data.Has_In'Access,
Old_Val => 2,
New_Val => 2
) )
then
Raise_Exception
( Mode_Error'Identity,
"The queue already has a non-multiplexed in-end"
);
end if;
end;
when Out_End =>
if not Compare_And_Swap
( Target => Queue.Data.Has_Out'Access,
Old_Val => 0,
New_Val => 1
)
then
Raise_Exception
( Mode_Error'Identity,
"The queue already has an out-end"
);
end if;
end case;
end Map;
procedure Peek_Implementation
( Queue : FIFO'Class;
Element : out Element_Type;
Empty : out Boolean;
Timeout : Duration := Duration'Last
) is
begin
if Queue.Data = null then
Raise_Exception (Status_Error'Identity, Out_End_Init);
end if;
declare
Data : FIFO_Data renames Queue.Data.all;
begin
Empty := Data.First = Data.Free;
if not Empty then
Element := Data.Buffer (Data.First);
end if;
end;
end Peek_Implementation;
procedure Peek
( Queue : FIFO_Out;
Element : out Element_Type;
Empty : out Boolean;
Timeout : Duration := Duration'Last
) is
begin
Peek_Implementation (Queue, Element, Empty, Timeout);
end Peek;
procedure Peek
( Queue : Universal_FIFO;
Element : out Element_Type;
Empty : out Boolean;
Timeout : Duration := Duration'Last
) is
begin
if Queue.Mode = Out_End then
Peek_Implementation (Queue, Element, Empty, Timeout);
else
Raise_Exception
( Mode_Error'Identity,
"An out-end of the queue is expected in Peek"
);
end if;
end Peek;
procedure Purge_Implementation
( Queue : in out FIFO'Class;
Is_Preserved : Is_Preserved_Ptr;
Purged : out Natural;
Timeout : Duration := Duration'Last
) is
begin
if Queue.Data = null then
Raise_Exception (Status_Error'Identity, Out_End_Init);
end if;
declare
Free : Positive renames Queue.Data.Free;
First : Positive renames Queue.Data.First;
Buffer : Element_Array renames Queue.Data.Buffer;
From : Positive := Free;
To : Positive := From;
begin
Purged := 0;
while From /= First loop
if From = 1 then
From := Queue.Size;
else
From := From - 1;
end if;
if Is_Preserved (Buffer (From)) then
-- Preserve this element
if To = 1 then
To := Queue.Size;
else
To := To - 1;
end if;
if To /= From then
Buffer (To) := Buffer (From);
end if;
else
-- Remove this one
Purged := Purged + 1;
end if;
end loop;
if Purged > 0 then
First := To;
Signal (Queue.Not_Full.all);
end if;
end;
end Purge_Implementation;
procedure Purge
( Queue : in out FIFO_Out;
Is_Preserved : Is_Preserved_Ptr;
Purged : out Natural;
Timeout : Duration := Duration'Last
) is
begin
Purge_Implementation (Queue, Is_Preserved, Purged, Timeout);
end Purge;
procedure Purge
( Queue : in out Universal_FIFO;
Is_Preserved : Is_Preserved_Ptr;
Purged : out Natural;
Timeout : Duration := Duration'Last
) is
begin
if Queue.Mode = Out_End then
Purge_Implementation (Queue, Is_Preserved, Purged, Timeout);
else
Raise_Exception
( Mode_Error'Identity,
"An out-end of the queue is expected in Purge"
);
end if;
end Purge;
procedure Purge_Implementation
( Queue : in out FIFO'Class;
Purged : out Natural;
Timeout : Duration := Duration'Last
) is
begin
if Queue.Data = null then
Raise_Exception (Status_Error'Identity, Out_End_Init);
end if;
declare
Free : Positive renames Queue.Data.Free;
First : Positive renames Queue.Data.First;
Buffer : Element_Array renames Queue.Data.Buffer;
From : Positive := Free;
To : Positive := From;
begin
Purged := 0;
while From /= First loop
if From = 1 then
From := Queue.Size;
else
From := From - 1;
end if;
if Is_Preserved
( Queue => FIFO_Out'Class (Queue),
Element => Buffer (From)
)
then
-- Preserve this element
if To = 1 then
To := Queue.Size;
else
To := To - 1;
end if;
if To /= From then
Buffer (To) := Buffer (From);
end if;
else
-- Remove this one
Purged := Purged + 1;
end if;
end loop;
if Purged > 0 then
First := To;
Signal (Queue.Not_Full.all);
end if;
end;
end Purge_Implementation;
procedure Purge
( Queue : in out FIFO_Out;
Purged : out Natural;
Timeout : Duration := Duration'Last
) is
begin
Purge_Implementation (Queue, Purged, Timeout);
end Purge;
procedure Purge
( Queue : in out Universal_FIFO;
Purged : out Natural;
Timeout : Duration := Duration'Last
) is
begin
if Queue.Mode = Out_End then
Purge_Implementation (Queue, Purged, Timeout);
else
Raise_Exception
( Mode_Error'Identity,
"An out-end of the queue is expected in Purge"
);
end if;
end Purge;
procedure Put_Lock_Free
( Queue : in out FIFO'Class;
Element : Element_Type;
Timeout : Duration := Duration'Last
) is
Started : constant Time := Clock;
begin
if Queue.Data = null then
Raise_Exception (Status_Error'Identity, In_End_Init);
end if;
declare
Free : Positive renames Queue.Data.Free;
First : Positive renames Queue.Data.First;
Buffer : Element_Array renames Queue.Data.Buffer;
begin
loop
declare
Count : Integer := First - Free;
begin
if Count /= 1 and then Count /= 1 - Queue.Size then
Buffer (Free) := Element;
if Free = Queue.Size then
Free := 1;
else
Free := Free + 1;
end if;
Signal (Queue.Not_Empty.all);
return;
end if;
Reset (Queue.Not_Full.all); -- Prepare to wait
Count := First - Free;
if Count = 1 or else Count = 1 - Queue.Size then
Wait
( Queue.Not_Full.all,
Timeout - (Clock - Started)
);
end if;
end;
end loop;
end;
end Put_Lock_Free;
procedure Put
( Queue : in out FIFO_In;
Element : Element_Type;
Timeout : Duration := Duration'Last
) is
begin
Put_Lock_Free (Queue, Element, Timeout);
end Put;
procedure Put_Interlocked
( Queue : in out FIFO'Class;
Element : Element_Type;
Lock : in out Mutex'Class;
Timeout : Duration := Duration'Last
) is
Started : constant Time := Clock;
begin
if Queue.Data = null then
Raise_Exception (Status_Error'Identity, In_End_Init);
end if;
declare
Free : Positive renames Queue.Data.Free;
First : Positive renames Queue.Data.First;
Buffer : Element_Array renames Queue.Data.Buffer;
begin
Seize (Lock, Timeout);
loop
declare
Count : Integer := First - Free;
begin
if Count /= 1 and then Count /= 1 - Queue.Size then
Buffer (Free) := Element;
if Free = Queue.Size then
Free := 1;
else
Free := Free + 1;
end if;
Release (Lock);
Signal (Queue.Not_Empty.all);
return;
end if;
Reset (Queue.Not_Full.all); -- Prepare to wait
Count := First - Free;
if Count = 1 or else Count = 1 - Queue.Size then
Wait
( Queue.Not_Full.all,
Timeout - (Clock - Started)
);
end if;
end;
end loop;
exception
when others =>
Release (Lock);
raise;
end;
end Put_Interlocked;
procedure Put
( Queue : in out FIFO_Multiplexed_In;
Element : Element_Type;
Timeout : Duration := Duration'Last
) is
begin
Put_Interlocked (Queue, Element, Queue.Lock.all, Timeout);
end Put;
procedure Put
( Queue : in out Universal_FIFO;
Element : Element_Type;
Timeout : Duration := Duration'Last
) is
begin
case Queue.Mode is
when In_End =>
Put_Lock_Free (Queue, Element, Timeout);
when Multiplexed_In_End =>
Put_Interlocked (Queue, Element, Queue.Lock.all, Timeout);
when Out_End =>
Raise_Exception
( Mode_Error'Identity,
"An in-end of the queue is expected in Put"
);
end case;
end Put;
procedure Set_Mode
( Queue : in out Universal_FIFO;
Mode : FIFO_End
) is
begin
if Queue.Data /= null then
Raise_Exception
( Status_Error'Identity,
"The queue is already initialized"
);
end if;
Queue.Mode := Mode;
end Set_Mode;
procedure Wait_For_Not_Empty
( Queue : in out FIFO;
Timeout : Duration
) is
begin
if Is_Empty (Queue) then
Reset (Queue.Not_Empty.all);
if Is_Empty (Queue) then -- Still empty, enter wait
Wait (Queue.Not_Empty.all, Timeout);
end if;
end if;
end Wait_For_Not_Empty;
procedure Wait_For_Not_Empty
( Queue : in out FIFO;
Timeout : Duration;
Empty : out Boolean
) is
Signaled : Boolean;
begin
if Is_Empty (Queue) then
Reset (Queue.Not_Empty.all);
if Is_Empty (Queue) then -- Still empty, enter wait
Wait (Queue.Not_Empty.all, Timeout, Signaled);
end if;
Empty := Is_Empty (Queue);
else
Empty := False;
end if;
end Wait_For_Not_Empty;
procedure Wait_For_Not_Full
( Queue : in out FIFO;
Timeout : Duration
) is
begin
if Is_Full (Queue) then
Reset (Queue.Not_Full.all);
if Is_Full (Queue) then -- Still full, enter wait
Wait (Queue.Not_Full.all, Timeout);
end if;
end if;
end Wait_For_Not_Full;
procedure Wait_For_Not_Full
( Queue : in out FIFO;
Timeout : Duration;
Full : out Boolean
) is
Signaled : Boolean;
begin
if Is_Full (Queue) then
Reset (Queue.Not_Full.all);
if Is_Full (Queue) then -- Still full, enter wait
Wait (Queue.Not_Full.all, Timeout, Signaled);
end if;
Full := Is_Full (Queue);
else
Full := False;
end if;
end Wait_For_Not_Full;
end Synchronization.Interprocess.Generic_FIFO;
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