File : agpl-streams-memory_arrays.ads


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--  $Id: agpl-streams-memory_arrays.ads,v 1.1 2004/02/24 15:26:10 Jano Exp $


--  Allows reading from an array viewed as an stream:

--  or writing to it.

--  Mixing the two operations is erroneous.


with Ada.Streams;                use Ada.Streams;

package Agpl.Streams.Memory_arrays is

   -- New stream type:

   -- Takes an access to an element array. It should remain allocated

   -- during the life of this stream.

   -- It will not be deallocated

   type Stream_type (
      Data  : access Stream_element_array) is new 
      Ada.Streams.Root_Stream_Type with private;

   type Stream_access is access all Stream_type;

   ------------------------------------------------------------------------

   -- Read                                                               --

   ------------------------------------------------------------------------

   procedure Read (
      Stream : in out Stream_type;
      Item   : out Stream_Element_Array;
      Last   : out Stream_Element_Offset);

   ------------------------------------------------------------------------

   -- Write                                                              --

   ------------------------------------------------------------------------

   -- Can cause constraint_error if the supplied buffer is exhausted.

        procedure Write (
      Stream : in out Stream_type;
      Item   : in Stream_Element_Array);

   ------------------------------------------------------------------------

   -- Index                                                              --

   ------------------------------------------------------------------------

   -- Amount of data written / read.

   function Index (Stream : in Stream_type) return Stream_element_offset;

   ------------------------------------------------------------------------

   -- Set_index                                                          --

   ------------------------------------------------------------------------

   -- Set starting position for read/write (First is 1)

   procedure Set_index (
      Stream : in out Stream_type;
      Index  : in     Stream_element_offset);

   ------------------------------------------------------------------------

   -- End_of_stream                                                      --

   ------------------------------------------------------------------------

   function End_of_stream (Stream : in Stream_type) return boolean;

private

   type Stream_type (
      Data  : access Stream_element_array) is new Ada.Streams.Root_Stream_Type
   with record
      Pos : Stream_element_offset := Data.all'First;
   end record;

end Agpl.Streams.Memory_arrays;