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------------------------------------------------------------------------------
-- Generic memory stream --
-- --
-- Copyright (C) 2003-2005 --
-- 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. --
-- --
------------------------------------------------------------------------------
generic
type Element is private;
type Element_Index is range <>;
type Element_Array is array (Element_Index range <>) of Element;
type Element_Access is access Element_Array;
type Constant_Access is access constant Element_Array;
First_Block_Length : in Element_Index := 256;
Next_Block_Length : in Element_Index := 1_024;
package Memory_Streams is
type Stream_Type is limited private;
subtype Element_Offset is Element_Index'Base range 0 .. Element_Index'Last;
procedure Append
(Stream : in out Stream_Type;
Value : in Element_Array;
Trim : in Boolean := False);
-- Append the data to the resource.
-- Set Trim to true disable remaining free spaces at the end of stream,
-- Set Trim to true for every call to stream would decrease performance.
procedure Append
(Stream : in out Stream_Type;
Data : in Element_Access);
-- Append dynamically allocated data or access to the static data
-- to the stream. Application must not use Data after send it to the
-- Stream. Stream would care about it, and free when necessary.
procedure Append
(Stream : in out Stream_Type;
Data : in Constant_Access);
-- Append dynamically allocated data or access to the static data
-- to the stream. Application could use Data after send it to the
-- Stream.
function Size (Stream : in Stream_Type) return Element_Offset;
-- Returns the size of the stream in bytes
procedure Reset (Stream : in out Stream_Type);
-- Set read index at the start of the stream
procedure Set_Index
(Stream : in out Stream_Type;
To : in Element_Offset);
-- Set the position in the stream, next Read will start at the position
-- whose index is To. If To is outside the content the index is set to
-- Last + 1 to ensure that next End_Of_File will return True.
function End_Of_File (Stream : in Stream_Type) return Boolean;
-- Returns true if there is no more data to read on the stream
procedure Read
(Stream : in out Stream_Type;
Buffer : out Element_Array;
Last : out Element_Offset);
-- Read a chunk of data from File and put them into Buffer. Last is the
-- index of the last item returned in Buffer.
procedure Close (Stream : in out Stream_Type);
-- Close File.
procedure Clear (Stream : in out Stream_Type) renames Close;
private
type Buffer_Type;
type Buffer_Access is access all Buffer_Type;
type Buffer_Type (Steady : Boolean) is record
Next : Buffer_Access;
case Steady is
when True => Const : Constant_Access;
when False => Data : Element_Access;
end case;
end record;
type Stream_Type is limited record
First : Buffer_Access;
Current : Buffer_Access;
Last : Buffer_Access;
Last_Length : Element_Offset := 0;
Length : Element_Offset := 0;
Current_Offset : Element_Index := 1;
end record;
end Memory_Streams;
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