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|
------------------------------------------------------------------------------
-- Generic memory stream --
-- --
-- Copyright (C) 2003-2015, Dmitriy Anisimkov --
-- --
-- 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. --
------------------------------------------------------------------------------
pragma Ada_2012;
with Ada.Unchecked_Deallocation;
package body Memory_Streams is
procedure Free (Item : in out Buffer_Access);
procedure Free is
new Ada.Unchecked_Deallocation (Element_Array, Element_Access);
procedure Trim_Last_Block (Stream : in out Stream_Type);
-- Remove unused space from last buffer
function First (Item : in Buffer_Access) return Element_Index with Inline;
function Last (Item : in Buffer_Access) return Element_Index with Inline;
------------
-- Append --
------------
procedure Append
(Stream : in out Stream_Type;
Value : in Element_Array;
Trim : in Boolean := False) is
begin
if Value'Length = 0 then
if Trim then
Trim_Last_Block (Stream);
end if;
return;
end if;
if Stream.First = null then
Stream.First := new Buffer_Type (False);
if Value'Length >= First_Block_Length or else Trim then
Stream.First.Data := new Element_Array (1 .. Value'Length);
else
Stream.First.Data := new Element_Array (1 .. First_Block_Length);
end if;
Stream.First.Data (1 .. Value'Length) := Value;
Stream.Current := Stream.First;
Stream.Last := Stream.First;
Stream.Last_Length := Value'Length;
elsif Stream.Last.Steady
or else Stream.Last_Length = Stream.Last.Data'Length
then
Stream.Last.Next := new Buffer_Type (False);
Stream.Last := Stream.Last.Next;
if Value'Length >= Next_Block_Length or else Trim then
Stream.Last.Data := new Element_Array (1 .. Value'Length);
else
Stream.Last.Data := new Element_Array (1 .. Next_Block_Length);
end if;
Stream.Last.Data (1 .. Value'Length) := Value;
Stream.Last_Length := Value'Length;
else
declare
Block_Length : constant Element_Offset :=
Stream.Last_Length + Value'Length;
begin
if Block_Length <= Stream.Last.Data'Length then
Stream.Last.Data
(Stream.Last_Length + 1 .. Block_Length) := Value;
Stream.Last_Length := Block_Length;
if Trim then
Trim_Last_Block (Stream);
end if;
else
declare
Split_Value : constant Element_Index :=
Value'First
+ Stream.Last.Data'Length
- Stream.Last_Length;
Next_Length : constant Element_Index :=
Value'Last - Split_Value + 1;
begin
Stream.Last.Data
(Stream.Last_Length + 1 .. Stream.Last.Data'Last) :=
Value (Value'First .. Split_Value - 1);
Stream.Last.Next := new Buffer_Type (False);
Stream.Last := Stream.Last.Next;
if Next_Length >= Next_Block_Length or else Trim then
Stream.Last.Data := new Element_Array (1 .. Next_Length);
else
Stream.Last.Data :=
new Element_Array (1 .. Next_Block_Length);
end if;
Stream.Last.Data (1 .. Next_Length) :=
Value (Split_Value .. Value'Last);
Stream.Last_Length := Next_Length;
end;
end if;
end;
end if;
Stream.Length := Stream.Length + Value'Length;
end Append;
------------
-- Append --
------------
procedure Append
(Stream : in out Stream_Type;
Data : in Constant_Access) is
begin
if Data'Length = 0 then
return;
end if;
if Stream.First = null then
Stream.First := new Buffer_Type (True);
Stream.First.Const := Data;
Stream.Current := Stream.First;
Stream.Last := Stream.First;
Stream.Last_Length := Data'Length;
Stream.Current_Offset := Data'First;
else
Trim_Last_Block (Stream);
Stream.Last.Next := new Buffer_Type (True);
Stream.Last := Stream.Last.Next;
Stream.Last.Const := Data;
Stream.Last_Length := Data'Length;
end if;
Stream.Length := Stream.Length + Data'Length;
end Append;
procedure Append
(Stream : in out Stream_Type;
Data : in Element_Access) is
begin
if Data'Length = 0 then
return;
end if;
if Stream.First = null then
Stream.First := new Buffer_Type (False);
Stream.First.Data := Data;
Stream.Current := Stream.First;
Stream.Last := Stream.First;
Stream.Last_Length := Data'Length;
Stream.Current_Offset := Data'First;
else
Trim_Last_Block (Stream);
Stream.Last.Next := new Buffer_Type (False);
Stream.Last := Stream.Last.Next;
Stream.Last.Data := Data;
Stream.Last_Length := Data'Length;
end if;
Stream.Length := Stream.Length + Data'Length;
end Append;
-----------
-- Close --
-----------
procedure Close (Stream : in out Stream_Type) is
First : Buffer_Access;
Length : Element_Offset := 0;
begin
while Stream.First /= null loop
First := Stream.First;
if First.Next = null then
Length := Length + Stream.Last_Length;
else
if First.Steady then
Length := Length + First.Const'Length;
else
Length := Length + First.Data'Length;
end if;
end if;
Stream.First := First.Next;
Free (First);
end loop;
Stream.Current := null;
Stream.Last := null;
Reset (Stream);
if Stream.Length /= Length then
raise Program_Error;
end if;
Stream.Length := 0;
end Close;
-----------------
-- End_Of_File --
-----------------
function End_Of_File (Stream : in Stream_Type) return Boolean is
begin
return Stream.Current = null
or else (Stream.Current.Next = null
and then Stream.Current_Offset > Last (Stream.Current));
end End_Of_File;
-----------
-- First --
-----------
function First (Item : in Buffer_Access) return Element_Index is
begin
if Item.Steady then
return Item.Const'First;
else
return Item.Data'First;
end if;
end First;
----------
-- Free --
----------
procedure Free (Item : in out Buffer_Access) is
procedure Deallocate is
new Ada.Unchecked_Deallocation (Buffer_Type, Buffer_Access);
begin
if not Item.Steady then
Free (Item.Data);
end if;
Deallocate (Item);
end Free;
----------
-- Last --
----------
function Last (Item : in Buffer_Access) return Element_Index is
begin
if Item.Steady then
return Item.Const'Last;
else
return Item.Data'Last;
end if;
end Last;
-------------
-- Pending --
-------------
function Pending (Stream : in Stream_Type) return Element_Offset is
begin
if Stream.Current = null then
return 0;
else
declare
B : Buffer_Access := Stream.Current;
S : Element_Offset := 0;
begin
while B /= null loop
if B.Next = null then
if B.Steady then
S := S + Last (B);
else
S := S + Stream.Last_Length - Stream.Current_Offset + 1;
end if;
else
S := S + Last (B);
end if;
B := B.Next;
end loop;
return S;
end;
end if;
end Pending;
----------
-- Read --
----------
procedure Read
(Stream : in out Stream_Type;
Buffer : out Element_Array;
Last : out Element_Offset)
is
Buffer_Offset : Element_Offset := Buffer'First;
Block_Over : Boolean;
procedure Append (Data : in Element_Array);
-- Add the Data to the Buffer till necessary from the
-- Resource.Current_Offset and move it.
------------
-- Append --
------------
procedure Append (Data : in Element_Array) is
Buffer_Len_1 : constant Element_Offset :=
Buffer'Last - Buffer_Offset;
-- Buffer remain length minus 1
Current_Len_1 : constant Element_Offset :=
Data'Last - Stream.Current_Offset;
-- Data remain length minus 1
Current_Last : Element_Index;
begin
Block_Over := Buffer_Len_1 >= Current_Len_1;
if Block_Over then
Last := Buffer_Offset + Current_Len_1;
Buffer (Buffer_Offset .. Last) :=
Data (Stream.Current_Offset .. Data'Last);
Buffer_Offset := Last + 1;
Stream.Current_Offset := Data'Last + 1;
else
Last := Buffer'Last;
Current_Last := Stream.Current_Offset + Buffer_Len_1;
Buffer (Buffer_Offset .. Last) :=
Data (Stream.Current_Offset .. Current_Last);
Stream.Current_Offset := Current_Last + 1;
end if;
end Append;
begin
Last := Buffer'First - 1;
if Stream.Current = null then
return;
end if;
loop
if Stream.Current.Next = null then
-- Last block
if Stream.Current.Steady then
Append (Stream.Current.Const.all);
else
Append (Stream.Current.Data
(Stream.Current.Data'First
.. Stream.Last_Length + Stream.Current.Data'First
- 1));
end if;
if Block_Over then
Stream.Current := null;
exit;
end if;
else
if Stream.Current.Steady then
Append (Stream.Current.Const.all);
else
Append (Stream.Current.Data.all);
end if;
if Block_Over then
Stream.Current := Stream.Current.Next;
Stream.Current_Offset := First (Stream.Current);
end if;
end if;
exit when Last = Buffer'Last;
end loop;
end Read;
-----------
-- Reset --
-----------
procedure Reset (Stream : in out Stream_Type) is
begin
Stream.Current := Stream.First;
Stream.Current_Offset := 1;
end Reset;
---------------
-- Set_Index --
---------------
procedure Set_Index
(Stream : in out Stream_Type;
To : in Element_Offset)
is
Idx : Element_Offset := Last (Stream.First);
begin
if To < 1 or else To > Size (Stream) then
Stream.Current := Stream.Last;
Stream.Current_Offset := Last (Stream.Current) + 1;
else
Stream.Current := Stream.First;
while Idx < To loop
Stream.Current := Stream.Current.Next;
Idx := Idx + Last (Stream.Current);
end loop;
Stream.Current_Offset := Last (Stream.Current) - Idx + To;
end if;
end Set_Index;
----------
-- Size --
----------
function Size (Stream : in Stream_Type) return Element_Offset is
begin
return Stream.Length;
end Size;
----------------------
-- Trim_Last_Buffer --
----------------------
procedure Trim_Last_Block (Stream : in out Stream_Type) is
begin
if Stream.Last = null
or else Stream.Last.Steady
or else Stream.Last.Data'Length = Stream.Last_Length
then
return;
end if;
declare
Ptr : constant Element_Access :=
new Element_Array'
(Stream.Last.Data (1 .. Stream.Last_Length));
begin
Free (Stream.Last.Data);
Stream.Last.Data := Ptr;
Stream.Last_Length := Ptr'Length;
end;
end Trim_Last_Block;
end Memory_Streams;
|
