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smg_comms_skeys_s...    1  -- Data structures for SMG Communication Protocol
smg_comms_skeys_s...    2  -- S.MG, 2018
smg_comms_skeys_s...    3 
smg_comms_skeys_s...    4 with Interfaces; -- for fixed-size types
smg_comms_skeys_s...    5 with Raw_Types;  -- for protocol raw types
smg_comms_skeys_s...    6 with System;     -- for Bit_Order
smg_comms_skeys_s...    7 with Serpent;    -- for Serpent.Key type
smg_comms_keymgm        8 with Ada.Unchecked_Conversion; -- for counter_8bits to/from octet
smg_comms_skeys_s...    9 
smg_comms_skeys_s...   10 package Data_Structs is
smg_comms_skeys_s...   11   Pragma Pure(Data_Structs);
smg_comms_skeys_s...   12 
smg_comms_skeys_s...   13   -- an object in the world, with record layout fully specified
smg_comms_skeys_s...   14   -- a storage element is 8-bit aka 1 octet
smg_comms_skeys_s...   15   -- "at" gives number of storage element
smg_comms_skeys_s...   16   -- "range" gives bits inside storage element
smg_comms_skeys_s...   17 
smg_comms_skeys_s...   18   type SMG_Object is
smg_comms_skeys_s...   19     record
smg_comms_skeys_s...   20       -- ID of the object
smg_comms_skeys_s...   21       ID         : Interfaces.Unsigned_32;
smg_comms_skeys_s...   22 
smg_comms_skeys_s...   23       -- Position of the object in the world.
smg_comms_skeys_s...   24       -- For a world with map coordinates (MC) between -500 and +500,
smg_comms_skeys_s...   25       -- the relationship with given figure (GF) is:
smg_comms_skeys_s...   26       -- MC = GF / 65.535 - 500
smg_comms_skeys_s...   27       -- where 65.535 comes from the mapping 65535 / (500 - - 500)
smg_comms_skeys_s...   28       X, Y, Z    : Interfaces.Integer_16;
smg_comms_skeys_s...   29 
smg_comms_skeys_s...   30       -- Rotation of the object (RO) linked to GF by:
smg_comms_skeys_s...   31       -- RO = GF / 128*pi
smg_comms_skeys_s...   32       RX, RY, RZ : Interfaces.Unsigned_8;
smg_comms_skeys_s...   33     end record;
smg_comms_skeys_s...   34   for SMG_Object'Size use 104; -- in bits!
smg_comms_skeys_s...   35   for SMG_Object'Bit_Order use System.Low_Order_First;
smg_comms_skeys_s...   36   for SMG_Object use
smg_comms_skeys_s...   37     record
smg_comms_skeys_s...   38       ID at 0  range 0 .. 31;
smg_comms_skeys_s...   39       X  at 4  range 0 .. 15;
smg_comms_skeys_s...   40       Y  at 6  range 0 .. 15;
smg_comms_skeys_s...   41       Z  at 8  range 0 .. 15;
smg_comms_skeys_s...   42       RX at 10 range 0 .. 7;
smg_comms_skeys_s...   43       RY at 11 range 0 .. 7;
smg_comms_skeys_s...   44       RZ at 12 range 0 .. 7;
smg_comms_skeys_s...   45     end record;
smg_comms_skeys_s...   46 
smg_comms_skeys_s...   47   -------------------------
smg_comms_skeys_s...   48   -- A set of Serpent Keys
smg_comms_skeys_s...   49   -- parametrized record for a Serpent Keyset 
smg_comms_skeys_s...   50   -- parameters: 
smg_comms_skeys_s...   51   --   N is number of Serpent Keys contained
smg_comms_skeys_s...   52   -- this can be the content of messages 4.1 or 5.2 in protocol spec.
smg_comms_skeys_s...   53 
smg_comms_skeys_s...   54   -- an array of Serpent Keys
smg_comms_skeys_s...   55   -- MAXIMUM 40 keys allowed in a message, hence subtype for key count
smg_comms_skeys_s...   56   subtype Keys_Count is Interfaces.Unsigned_8 range 1..40;
smg_comms_skeys_s...   57   type SKeys_Array is array( Keys_Count range <>) of Serpent.Key;
smg_comms_skeys_s...   58 
smg_comms_skeys_s...   59   type Serpent_Keyset( N : Keys_Count := Keys_Count'Last) is
smg_comms_skeys_s...   60     record
smg_comms_skeys_s...   61       -- actual Serpent Keys
smg_comms_skeys_s...   62       Keys      : SKeys_Array( 1..N );
smg_comms_skeys_s...   63       -- whether for talking to client (LSB set) or talking to server (MSB set)
smg_comms_skeys_s...   64       Flag      : Interfaces.Unsigned_8;
smg_comms_skeys_s...   65     end record;
smg_comms_skeys_s...   66 
smg_comms_skeys_s...   67   ------------------------------
smg_comms_skeys_s...   68   -- Serpent Keys Management
smg_comms_keymgm       69   subtype Counter_8bits is Natural range 0..255;
smg_comms_keymgm       70   function Cast is new Ada.Unchecked_Conversion( Counter_8bits, 
smg_comms_keymgm       71                                                  Raw_Types.Octets_1 );  
smg_comms_keymgm       72   function Cast is new Ada.Unchecked_Conversion( Raw_Types.Octets_1, 
smg_comms_keymgm       73                                                  Counter_8bits );
smg_comms_keymgm       74   type Keys_Mgm (N_Burnt: Counter_8bits := 0) is
smg_comms_skeys_s...   75     record
smg_comms_skeys_s...   76       -- count of server keys requested
smg_comms_skeys_s...   77       N_Server: Interfaces.Unsigned_8; 
smg_comms_skeys_s...   78       -- count of client keys requested
smg_comms_skeys_s...   79       N_Client: Interfaces.Unsigned_8;
smg_comms_skeys_s...   80       -- ID of Serpent key preferred for further inbound Serpent msgs.
smg_comms_skeys_s...   81       Key_ID  : Interfaces.Unsigned_8;
smg_comms_skeys_s...   82       -- IDs of Serpent keys burnt by this message
smg_comms_keymgm       83       case N_Burnt is
smg_comms_keymgm       84         when 0 =>
smg_comms_keymgm       85           null;
smg_comms_keymgm       86         when others =>
smg_comms_keymgm       87           Burnt   : Raw_Types.Octets( 1..N_Burnt );
smg_comms_keymgm       88       end case;
smg_comms_skeys_s...   89     end record;
smg_comms_skeys_s...   90 
smg_comms_skeys_s...   91 end Data_Structs;