-- S.MG, 2018
  -- prototype implementation of S.MG communication protocol

with SMG_comms_types; use SMG_comms_types;
with System; use System; -- endianness
with Ada.Exceptions;
with Ada.Streams; use Ada.Streams; 

package body SMG_comms_types is

  -- to and from network format (i.e. big endian, stream_element_array)
  procedure ToNetworkFormat(
      Item   : in Octet_Array;
      Buffer : out Stream_Element_Array) is
  begin
    if Item'Length /= Buffer'Length then
      raise Constraint_Error with "Item and Buffer lengths do NOT match!";
    end if;

    if Default_Bit_Order = Low_Order_First then
      for I in 0 .. Item'Length - 1 loop
        Buffer( Buffer'Last - Stream_Element_Offset(I) ) := Stream_Element(Item(Item'First + I));
      end loop;
    else
      for I in 0 .. Item'Length - 1 loop
        Buffer( Buffer'First + Stream_Element_Offset(I) ) := Stream_Element(Item(Item'First + I));
      end loop;
    end if;
  end ToNetworkFormat;

  procedure FromNetworkFormat(
      Buffer : in Stream_Element_Array;
      Item   : out Octet_Array) is
  begin
    if Item'Length /= Buffer'Length then
      raise Constraint_Error with "Buffer and Item length do NOT match!";
    end if;

    if Default_Bit_Order = Low_Order_First then
      for I in 0 .. Buffer'Length - 1 loop
        Item( Item'Last - I ) := 
          Unsigned_8( Buffer( Buffer'First + Stream_Element_Offset( I ) ) );
      end loop;
    else
      for I in 0 .. Buffer'Length - 1 loop
        Item( Item'First + I ) := 
          Unsigned_8( Buffer( Buffer'First + Stream_Element_Offset( I ) ) );
      end loop;
    end if;    
  end FromNetworkFormat;

  -- Integer_8
  procedure ToNetworkFormat(
      Item   : in Integer_8;
      Buffer : out Stream_Element_Array) is
  begin
    ToNetworkFormat( Cast( Item ), Buffer );
  end ToNetworkFormat;

  procedure FromNetworkFormat(
      Buffer : in Stream_Element_Array;
      Item   : out Integer_8) is
    octets: Octets_1;
  begin
    FromNetworkFormat(Buffer, octets);
    Item := Cast( octets );
  end FromNetworkFormat;

end SMG_comms_types;