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

with Ada.Streams; use Ada.Streams;
with Interfaces; use Interfaces; -- Integer_n and Unsigned_n
with Ada.Unchecked_Conversion; -- converting int/uint to array of octets

package SMG_comms_types is
  -- basic types with guaranteed lengths
  type Octet_Array is array(Natural range <>) of Unsigned_8;

  subtype Octets_1 is Octet_Array( 1 .. 1 );
  subtype Octets_2 is Octet_Array( 1 .. 2 );
  subtype Octets_4 is Octet_Array( 1 .. 4 );
  subtype Octets_8 is Octet_Array( 1 .. 8 );

  subtype Message is Octet_Array( 1 .. 512 );
  subtype RSAMessage is Octet_Array( 1 .. 245 );

  -- blind, unchecked casts ( memcpy style )
  function Cast is new Ada.Unchecked_Conversion( Integer_8, Octets_1 );
  function Cast is new Ada.Unchecked_Conversion( Octets_1, Integer_8 );

  function Cast is new Ada.Unchecked_Conversion( Integer_16, Octets_2 );
  function Cast is new Ada.Unchecked_Conversion( Octets_2, Integer_16 );

  function Cast is new Ada.Unchecked_Conversion( Integer_32, Octets_4 );
  function Cast is new Ada.Unchecked_Conversion( Octets_4, Integer_32 );

  function Cast is new Ada.Unchecked_Conversion( Integer_64, Octets_8 );
  function Cast is new Ada.Unchecked_Conversion( Octets_8, Integer_64 );

  -- to and from streams for network communications - general
  procedure ToNetworkFormat(
      Item   : in Octet_Array;
      Buffer : out Stream_Element_Array);

  procedure FromNetworkFormat(
      Buffer : in Stream_Element_Array;
      Item   : out Octet_Array);

  -- specific, convenience methods for the basic types
    -- Integer_8 
  procedure ToNetworkFormat(
      Item   : in Integer_8;
      Buffer : out Stream_Element_Array);

  procedure FromNetworkFormat(
      Buffer : in Stream_Element_Array;
      Item   : out Integer_8);

end SMG_comms_types;