raw
smg_comms_raw_types     1  -- raw types for the communication protocol
smg_comms_raw_types     2  -- these are used throughout at the lowest level of the protocol
smg_comms_raw_types     3  -- essentially they are the units of packets and of messages
smg_comms_raw_types     4  -- SMG.Comms has only 2 types of packets: RSA and Serpent
smg_comms_raw_types     5  -- a message is the decrypted content of a packet
smg_comms_raw_types     6  -- S.MG, 2018
smg_comms_raw_types     7 
smg_comms_raw_types     8 with Interfaces; use Interfaces; -- Unsigned_n and Integer_n
smg_comms_raw_types     9 with Ada.Unchecked_Conversion;
smg_comms_raw_types    10 
smg_comms_raw_types    11 package Raw_Types is
smg_comms_packing...   12   -- no side effects or internal state
smg_comms_packing...   13   Pragma Pure(Raw_Types);
smg_comms_raw_types    14 
smg_comms_raw_types    15   -- constants from SMG.COMMS standard specification
smg_comms_raw_types    16     -- size of a serpent-encrypted packet and message, in octets
smg_comms_raw_types    17     -- note that this corresponds to 1472/16 = 92 Serpent blocks
smg_comms_packing...   18     -- NB: lengths are the same!
smg_comms_packing...   19   SERPENT_OCTETS : constant Positive := 1472;
smg_comms_raw_types    20 
smg_comms_raw_types    21     -- size of a RSA-encrypted packet and message in octets and bits
smg_comms_raw_types    22   RSA_PKT_OCTETS     : constant Positive := 1470;
smg_comms_raw_types    23   RSA_MSG_OCTETS     : constant Positive := 234;
smg_comms_raw_types    24   RSA_MSG_BITS       : constant Positive := RSA_MSG_OCTETS * 8; --1872
smg_comms_raw_types    25 
smg_comms_raw_types    26   -- raw, low-level types
smg_comms_raw_types    27   -- all messages and packets are simply arrays of octets at low level/raw
smg_comms_raw_types    28   type Octets is array( Natural range <> ) of Interfaces.Unsigned_8;
smg_comms_raw_types    29 
smg_comms_raw_types    30   -- raw representations of basic types (with fixed, well-defined sizes)
smg_comms_raw_types    31   subtype Octets_1 is Octets( 1 .. 1 );
smg_comms_raw_types    32   subtype Octets_2 is Octets( 1 .. 2 );
smg_comms_raw_types    33   subtype Octets_4 is Octets( 1 .. 4 );
smg_comms_raw_types    34   subtype Octets_8 is Octets( 1 .. 8 );
smg_comms_raw_types    35 
smg_comms_raw_types    36   -- RSA packets and contained raw messages
smg_comms_raw_types    37   subtype RSA_Pkt is Octets( 1 .. RSA_PKT_OCTETS );
smg_comms_raw_types    38   subtype RSA_Msg is Octets( 1 .. RSA_MSG_OCTETS );
smg_comms_raw_types    39 
smg_comms_raw_types    40   -- Serpent packets and contained raw messages
smg_comms_raw_types    41   -- NB: length is the same but the distinction makes the code clearer
smg_comms_packing...   42   subtype Serpent_Pkt is Octets( 1 .. SERPENT_OCTETS );
smg_comms_packing...   43   subtype Serpent_Msg is Octets( 1 .. SERPENT_OCTETS );
smg_comms_raw_types    44 
smg_comms_raw_types    45   -- blind, unchecked casts ( memcpy style )
smg_comms_raw_types    46   function Cast is new Ada.Unchecked_Conversion( Integer_8  , Octets_1 );
smg_comms_raw_types    47   function Cast is new Ada.Unchecked_Conversion( Octets_1   , Integer_8 );
smg_comms_raw_types    48   function Cast is new Ada.Unchecked_Conversion( Unsigned_8 , Octets_1 );
smg_comms_raw_types    49   function Cast is new Ada.Unchecked_Conversion( Octets_1   , Unsigned_8 );
smg_comms_raw_types    50 
smg_comms_raw_types    51   function Cast is new Ada.Unchecked_Conversion( Integer_16 , Octets_2 );
smg_comms_raw_types    52   function Cast is new Ada.Unchecked_Conversion( Octets_2   , Integer_16 );
smg_comms_raw_types    53   function Cast is new Ada.Unchecked_Conversion( Unsigned_16, Octets_2 );
smg_comms_raw_types    54   function Cast is new Ada.Unchecked_Conversion( Octets_2   , Unsigned_16 );
smg_comms_raw_types    55 
smg_comms_raw_types    56   function Cast is new Ada.Unchecked_Conversion( Integer_32 , Octets_4 );
smg_comms_raw_types    57   function Cast is new Ada.Unchecked_Conversion( Octets_4   , Integer_32 );
smg_comms_raw_types    58   function Cast is new Ada.Unchecked_Conversion( Unsigned_32, Octets_4 );
smg_comms_raw_types    59   function Cast is new Ada.Unchecked_Conversion( Octets_4   , Unsigned_32 );
smg_comms_raw_types    60 
smg_comms_raw_types    61   -- Gnat's Float has 32 bits but this might be different with other compilers
smg_comms_raw_types    62   function Cast is new Ada.Unchecked_Conversion( Float, Octets_4 );
smg_comms_raw_types    63   function Cast is new Ada.Unchecked_Conversion( Octets_4, Float );
smg_comms_raw_types    64 
smg_comms_raw_types    65   function Cast is new Ada.Unchecked_Conversion( Integer_64, Octets_8 );
smg_comms_raw_types    66   function Cast is new Ada.Unchecked_Conversion( Octets_8, Integer_64 );
smg_comms_raw_types    67   function Cast is new Ada.Unchecked_Conversion( Unsigned_64, Octets_8 );
smg_comms_raw_types    68   function Cast is new Ada.Unchecked_Conversion( Octets_8, Unsigned_64 );
smg_comms_raw_types    69 
smg_comms_raw_types    70 end Raw_Types;