File : 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) 1992-2011, 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 -- --
19 -- --
20 -- --
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 -- This procedure returns the internal string pointer used in the
60 -- representation of an unbounded string as well as the actual current
61 -- length (which may be less than S.all'Length because in general there
62 -- can be extra space assigned). The characters of this string may be
63 -- not be modified via the returned pointer, and are valid only as
64 -- long as the original unbounded string is 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 (UP : in out Unbounded_String; S : String_Access);
72 pragma Inline (Set_String);
73 -- This version of Set_Unbounded_String takes a string access value, rather
74 -- than a string. The lower bound of the string value is required to be
75 -- one, and this requirement is not checked.
76
77 end Ada.Strings.Unbounded.Aux;