Re: Command line parameters

["Craig Garrett" <cgarrett@siscom.net>]

Here is some code that does exactly what you want: ( I apologize about the
indentation, cut and paste dont work that well)
- Craig

--  CreateOTP.ADA
--  Author: Craig Garrett
--  Ver 1.2
--  28 MAY 1998

--
****************************************************************************
**
-- Creates a OneTimePad to encrypt ANY file.

-- CREATEOTP [filename] [size]
        
--   [filename]    Specifies the name of the OneTimePad to be created.
--   [size]        Specifies the size of the OneTimePad in bytes.
        
-- NOTE: The OneTimePad MUST be as large or larger than the file to be
encrypted.
-- After this OneTimePad has been used once, delete it.  Do not use it
twice.

-- Also see ENCRYPT and DECRYPT for related commands.
--
****************************************************************************
**

with Ada.Command_Line;
with TEXT_IO;
use  TEXT_IO;
with RANDOM;
with Interfaces;
with SEQUENTIAL_IO;

procedure CreateOTP is

    package INT_IO is new TEXT_IO.INTEGER_IO (INTEGER);
    use INT_IO;
    package BYTE_FILE_IO is new SEQUENTIAL_IO(Interfaces.UNSIGNED_8);
    use BYTE_FILE_IO;
    
    procedure PRINT_HELP_INSTRUCTIONS is
    begin
        PUT("Creates a OneTimePad to encrypt ANY file."); NEW_LINE(2);
        
        PUT("CREATEOTP [filename] [size]");NEW_LINE(2);
        
        PUT("  [filename]    Specifies the name of the OneTimePad to be
created.");NEW_LINE;
        PUT("  [size]        Specifies the size of the OneTimePad in
bytes."); NEW_LINE(2);
        
        PUT("NOTE: The OneTimePad MUST be as large or larger than the file
to be encrypted.");NEW_LINE;
        PUT("After this OneTimePad has been used once, delete it.  Do not
use it twice.");NEW_LINE(2);
        
        PUT("Also see ENCRYPT and DECRYPT for related
commands.");NEW_LINE(2);
    end PRINT_HELP_INSTRUCTIONS;
    
    Command_Length  : NATURAL := 0; -- Used to specify a max length in the
GET call
    I               : INTEGER := 0;  -- Index for the for loop when writing
the OneTimePad
    OTPLength       : INTEGER := 0;-- Length in bytes of the OneTimePad to
be created
    OTP_FILE        : BYTE_FILE_IO.FILE_TYPE; -- File Pointer to the
OneTimePad
    OTP_NAME        : STRING(1..50) := "                                   
              ";
                      -- OneTimePad filename, 50 chars long just in case.
	OTP_BYTE        : Interfaces.UNSIGNED_8 := 0; -- Unsigned 8-bit Integer,
the byte written
    											  -- to the OneTimePad.
    
begin
    if Ada.Command_Line.Argument_Count = 2 then
        OTP_NAME(1..Ada.Command_Line.Argument(1)'Last) :=
Ada.Command_Line.Argument(1);
        Command_Length := Ada.Command_Line.Argument(2)'Last;
        GET(Ada.Command_Line.Argument(2), OTPLength, Command_Length);

    	CREATE(OTP_FILE, OUT_FILE, OTP_NAME);

       	PUT("CREATING ONE-TIME-PAD:  "); PUT(OTP_NAME);

    	RANDOM.GET_TIME_SEED;--Generates a new seed based on the system clock
for better randomness
    	for I in 1..OTPLength loop
            --Generate a random unsigned, 8-bit integer, and write it to
the file
    	    OTP_BYTE := Interfaces.Unsigned_8(RANDOM.NUMBER * 255.0);
    	    WRITE(OTP_FILE, OTP_BYTE);
   		end loop;

       	CLOSE(OTP_FILE);
    else
        -- Classic command line behavior, if no or incorrect command line
parameters...
        PRINT_HELP_INSTRUCTIONS;
    end if;
exception  -- This is in case the given command line parameters are
incorrect.
    when OTHERS =>
        PRINT_HELP_INSTRUCTIONS;
end CreateOTP;