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146 | -- --
-- package Copyright (c) Dmitry A. Kazakov --
-- Strings_Edit.Streams. Luebeck --
-- Generic_Modular Autumn, 2014 --
-- Implementation --
-- Last revision : 16:33 18 Nov 2016 --
-- --
-- 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.Exceptions; use Ada.Exceptions;
with Ada.IO_Exceptions; use Ada.IO_Exceptions;
package body Strings_Edit.Streams.Generic_Modular is
procedure Get
( Data : Stream_Element_Array;
Pointer : in out Stream_Element_Offset;
Value : out Number
) is
Result : Number := 0;
Old : Number := 0;
Power : Natural := 0;
begin
if ( Pointer < Data'First
or else
( Pointer > Data'Last
and then
Pointer - 1 > Data'Last
) )
then
Raise_Exception
( Layout_Error'Identity,
"Pointer is out of bounds"
);
end if;
while Pointer <= Data'Last loop
Result :=
Result + 2 ** Power * Number (Data (Pointer) and 16#7F#);
if Old > Result then
Raise_Exception
( Data_Error'Identity,
"Number is too large"
);
end if;
if 0 = (Data (Pointer) and 16#80#) then
Pointer := Pointer + 1;
Value := Result;
return;
end if;
Old := Result;
Power := Power + 7;
Pointer := Pointer + 1;
end loop;
Raise_Exception
( End_Error'Identity,
"Non-terminated chain sequence"
);
end Get;
function Input
( Stream : access Root_Stream_Type'Class
) return Number is
Result : Number := 0;
Old : Number := 0;
Power : Natural := 0;
Buffer : Stream_Element_Array (1..1);
Last : Stream_Element_Offset;
begin
loop
Read (Stream.all, Buffer, Last);
exit when Last /= 1;
Result :=
Result + 2 ** Power * Number (Buffer (1) and 16#7F#);
if Old > Result then
Raise_Exception
( Data_Error'Identity,
"Number is too large"
);
end if;
if 0 = (Buffer (1) and 16#80#) then
return Result;
end if;
Old := Result;
Power := Power + 7;
end loop;
Raise_Exception
( End_Error'Identity,
"Non-terminated chain sequence"
);
end Input;
procedure Output
( Stream : access Root_Stream_Type'Class;
Value : Number
) is
Buffer : Stream_Element_Array (1..Number'Size + 6 / 7);
Pointer : Stream_Element_Offset := 1;
begin
Put (Buffer, Pointer, Value);
Write (Stream.all, Buffer (1..Pointer - 1));
end Output;
procedure Put
( Data : in out Stream_Element_Array;
Pointer : in out Stream_Element_Offset;
Value : Number
) is
Item : Number := Value;
begin
if Pointer not in Data'Range then
Raise_Exception
( Layout_Error'Identity,
"Pointer is out of bounds"
);
end if;
while Pointer <= Data'Last loop
Data (Pointer) := Stream_Element (Item mod 16#80#) or 16#80#;
Pointer := Pointer + 1;
Item := Item / 16#80#;
if Item = 0 then
Data (Pointer - 1) := Data (Pointer - 1) and 16#7F#;
return;
end if;
end loop;
Raise_Exception (Layout_Error'Identity, "No room for output");
end Put;
end Strings_Edit.Streams.Generic_Modular;
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