gcc/ada/s-sopco3.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --           S Y S T E M . S T R I N G _ O P S _ C O N C A T _ 3            --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-1998, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 package body System.String_Ops_Concat_3 is
  35
  36    ------------------
  37    -- Str_Concat_3 --
  38    ------------------
  39
  40    function Str_Concat_3 (S1, S2, S3 : String) return String is
  41    begin
  42       if S1'Length <= 0 then
  43          return S2 & S3;
  44
  45       else
  46          declare
  47             L12 : constant Natural := S1'Length + S2'Length;
  48             L13 : constant Natural := L12 + S3'Length;
  49             R : String (S1'First .. S1'First + L13 - 1);
  50
  51          begin
  52             R (S1'First       .. S1'Last)            := S1;
  53             R (S1'Last + 1    .. S1'First + L12 - 1) := S2;
  54             R (S1'First + L12 .. R'Last)             := S3;
  55             return R;
  56          end;
  57       end if;
  58    end Str_Concat_3;
  59
  60 end System.String_Ops_Concat_3;