Ada.Strings.Fixed.Overwrite(), functionality & performance

["Markus Schöpflin" <no.spam@spam.spam>]

Hello,

I'm wondering if there is an efficient way to implement

    procedure OVERWRITE (SOURCE   : in out STRING;
                         POSITION : in out POSITIVE;
                         NEW_ITEM : in     STRING;
                         DROP     : in     TRUNCATION := RIGHT);

which should behave as

    procedure OVERWRITE (SOURCE   : in out STRING;
                         POSITION : in out POSITIVE;
                         NEW_ITEM : in     STRING;
                         DROP     : in     TRUNCATION := RIGHT)
    is begin
       ADA.STRINGS.FIXED.OVERWRITE (SOURCE, POSITION, NEW_ITEM, DROP);
       POSITION := POSITION + NATURAL'Min (NEW_ITEM'Length,
                                           SOURCE'Last - POSITION + 1);
    end;

using primitives from Ada.Strings.Fixed.

Currently I'm using a self-rolled version which turns out to be more than four 
times faster than the naive implementation above; but I'm wondering whether 
there isn't a better way to implement it just using primitives from 
Ada.Strings.Fixed.

Markus