gcc/ada/libgnat/a-stunau.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                          GNAT RUN-TIME COMPONENTS                        --
   4 --                                                                          --
   5 --            A D A . S T R I N G S . U N B O U N D E D . A U X             --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2024, 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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This child package of Ada.Strings.Unbounded provides some specialized
  33 --  access functions which are intended to allow more efficient use of the
  34 --  facilities of Ada.Strings.Unbounded, particularly by other layered
  35 --  utilities (such as GNAT.SPITBOL.Patterns).
  36
  37 package Ada.Strings.Unbounded.Aux is
  38    pragma Preelaborate;
  39
  40    subtype Big_String is String (1 .. Positive'Last);
  41    pragma Suppress_Initialization (Big_String);
  42    --  Type used to obtain string access to given address. Initialization is
  43    --  suppressed, since we never want to have variables of this type, and
  44    --  we never want to attempt initialiazation of virtual variables of this
  45    --  type (e.g. when pragma Normalize_Scalars is used).
  46
  47    type Big_String_Access is access all Big_String;
  48    for Big_String_Access'Storage_Size use 0;
  49    --  We use this access type to pass a pointer to an area of storage to be
  50    --  accessed as a string. Of course when this pointer is used, it is the
  51    --  responsibility of the accessor to ensure proper bounds. The storage
  52    --  size clause ensures we do not allocate variables of this type.
  53
  54    procedure Get_String
  55      (U : Unbounded_String;
  56       S : out Big_String_Access;
  57       L : out Natural);
  58    pragma Inline (Get_String);
  59    --  Return the internal string pointer used in the representation of an
  60    --  unbounded string as well as the actual current length (which may be less
  61    --  than S.all'Length because in general there can be extra space assigned).
  62    --  The characters of this string may be not be modified via the returned
  63    --  pointer, and are valid only as long as the original unbounded string is
  64    --  not accessed or modified.
  65    --
  66    --  This procedure is much more efficient than the use of To_String
  67    --  since it avoids the need to copy the string. The lower bound of the
  68    --  referenced string returned by this call is always one, so the actual
  69    --  string data is always accessible as S (1 .. L).
  70
  71    procedure Set_String
  72      (U      : out Unbounded_String;
  73       Length : Positive;
  74       Set    : not null access procedure (S : out String));
  75    pragma Inline (Set_String);
  76    --  Create an unbounded string U with the given Length, using Set to fill
  77    --  the contents of U.
  78
  79 end Ada.Strings.Unbounded.Aux;