File : adagio-memory_stream_constrained.adb
------------------------------------------------------------------------------
-- ADAGIO - ADALID - AENEA. --
-- --
-- Copyright (C) 2003 --
-- A. Mosteo. --
-- --
-- Authors: A. Mosteo. (adagio@mosteo.com) --
-- --
-- If you have any questions in regard to this software, please address --
-- them to the above email. --
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-- This program 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 program 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. --
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-- 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. --
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-- You are not allowed to use any part of this code to develop a program --
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------------------------------------------------------------------------------
-- $Id: adagio-memory_stream_constrained.adb,v 1.3 2004/01/21 21:05:41 Jano Exp $
with System.Address_to_access_conversions;
package body Adagio.Memory_stream_constrained is
package Convert is new System.Address_to_access_conversions (Big_array);
------------------------------------------------------------------------
-- Create --
------------------------------------------------------------------------
procedure Create (
Stream : out Stream_type;
Data : System.Address;
Length : Natural) is
begin
Stream.Buffer := Array_access (Convert.To_pointer (Data));
Stream.Length := Stream_element_offset (Length);
end Create;
------------------------------------------------------------------------
-- Read --
------------------------------------------------------------------------
procedure Read (
Stream : in out Stream_type;
Item : out Stream_Element_Array;
Last : out Stream_Element_Offset) is
begin
if Item'Length > Stream.Length - Stream.Pos + 1 then
Item (Item'First .. Item'First + Stream.Length - Stream.Pos) :=
Stream.Buffer (Stream.Pos .. Stream.Length);
Last := Item'First + Stream.Length - Stream.Pos;
Stream.Pos := Stream.Length + 1;
else
Item := Stream.Buffer (Stream.Pos .. Stream.Pos + Item'Length - 1);
Last := Item'Last;
Stream.Pos := Stream.Pos + Item'Length;
end if;
end Read;
------------------------------------------------------------------------
-- Write --
------------------------------------------------------------------------
procedure Write (
Stream : in out Stream_type;
Item : in Stream_Element_Array) is
Pos : Stream_element_offset renames Stream.Pos;
begin
if Pos + Item'Length - 1 > Stream.Length then
raise Constraint_error;
end if;
Stream.Buffer (Pos .. Pos + Item'Length - 1) := Item;
Pos := Pos + Item'Length;
end Write;
------------------------------------------------------------------------
-- Index --
------------------------------------------------------------------------
function Index (Stream : in Stream_type) return Stream_element_offset is
begin
return Stream.Pos - 1;
end Index;
------------------------------------------------------------------------
-- End_of_stream --
------------------------------------------------------------------------
function End_of_stream (Stream : in Stream_type) return boolean is
begin
return Stream.Pos > Stream.Length;
end End_of_stream;
end Adagio.Memory_stream_constrained;