From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,16016085da246cdf
X-Google-Attributes: gid103376,public
From: Stephen & Tammy House <house@ro.com>
Subject: Re: Looking for generic hash function
Date: 1996/08/16
Message-ID: <3215244B.4BBF@ro.com>#1/1
X-Deja-AN: 174648449
references: <4v23jd$mg9@News.Dal.Ca>
to: Robert Grandy <grandyre@newton.ccs.tuns.ca>
content-type: text/plain; charset=us-ascii
organization: RENAISSANCE INTERNET SERVICES
mime-version: 1.0
newsgroups: comp.lang.ada
x-mailer: Mozilla 3.0b6 (Win95; I)
Date: 1996-08-16T00:00:00+00:00
List-Id: <comp.lang.ada>


Robert Grandy wrote:
> 
> Hello,
> 
> I am looking for a function that will return a random-type integer based
> on a generic parameter. What I have in mind is:
> 
> generic
>   type data_type is private;
> function get_data_id return Integer;

You could try taking in one step further with:
generic
  type data_type is private;
  type id is (<>);
function data_id (d : data_type) return id;

function data_id (d : data_type) return id is
  type integers is array (integer range <>) of integer;
  local_d : constant data_type := d;
  --alias I integer array to same location as local_d, basically
begin
  return --normalize sum of all I into id'range
end data_id;

I don't remember all the syntax of alises, and I'd have to work out the
conversion into the id'range, but this should work for big or small
data_type structures.  Of course, if data_type'size < integer'size,
you'll need to have an alternate plan going.  You might make a local
integer type based upon min(data_type'size, standard.integer'size) to
avoid this problem.