PR target/16201
[official-gcc.git] / gcc / ada / i-cstrin.adb
blob6adb48ad94e81078b71ab3044cda6273b89a8b8c
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- I N T E R F A C E S . C . S T R I N G S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2004 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, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, 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 ------------------------------------------------------------------------------
34 with System; use System;
35 with System.Storage_Elements; use System.Storage_Elements;
37 with Unchecked_Conversion;
39 package body Interfaces.C.Strings is
41 -- Note that the type chars_ptr has a pragma No_Strict_Aliasing in
42 -- the spec, to prevent any assumptions about aliasing for values
43 -- of this type, since arbitrary addresses can be converted, and it
44 -- is quite likely that this type will in fact be used for aliasing
45 -- values of other types.
47 function To_chars_ptr is
48 new Unchecked_Conversion (Address, chars_ptr);
50 function To_Address is
51 new Unchecked_Conversion (chars_ptr, Address);
53 -----------------------
54 -- Local Subprograms --
55 -----------------------
57 function Peek (From : chars_ptr) return char;
58 pragma Inline (Peek);
59 -- Given a chars_ptr value, obtain referenced character
61 procedure Poke (Value : char; Into : chars_ptr);
62 pragma Inline (Poke);
63 -- Given a chars_ptr, modify referenced Character value
65 function "+" (Left : chars_ptr; Right : size_t) return chars_ptr;
66 pragma Inline ("+");
67 -- Address arithmetic on chars_ptr value
69 function Position_Of_Nul (Into : char_array) return size_t;
70 -- Returns position of the first Nul in Into or Into'Last + 1 if none
72 -- We can't use directly System.Memory because the categorization is not
73 -- compatible, so we directly import here the malloc and free routines.
75 function Memory_Alloc (Size : size_t) return chars_ptr;
76 pragma Import (C, Memory_Alloc, "__gnat_malloc");
78 procedure Memory_Free (Address : chars_ptr);
79 pragma Import (C, Memory_Free, "__gnat_free");
81 ---------
82 -- "+" --
83 ---------
85 function "+" (Left : chars_ptr; Right : size_t) return chars_ptr is
86 begin
87 return To_chars_ptr (To_Address (Left) + Storage_Offset (Right));
88 end "+";
90 ----------
91 -- Free --
92 ----------
94 procedure Free (Item : in out chars_ptr) is
95 begin
96 if Item = Null_Ptr then
97 return;
98 end if;
100 Memory_Free (Item);
101 Item := Null_Ptr;
102 end Free;
104 --------------------
105 -- New_Char_Array --
106 --------------------
108 function New_Char_Array (Chars : char_array) return chars_ptr is
109 Index : size_t;
110 Pointer : chars_ptr;
112 begin
113 -- Get index of position of null. If Index > Chars'last,
114 -- nul is absent and must be added explicitly.
116 Index := Position_Of_Nul (Into => Chars);
117 Pointer := Memory_Alloc ((Index - Chars'First + 1));
119 -- If nul is present, transfer string up to and including it.
121 if Index <= Chars'Last then
122 Update (Item => Pointer,
123 Offset => 0,
124 Chars => Chars (Chars'First .. Index),
125 Check => False);
126 else
127 -- If original string has no nul, transfer whole string and add
128 -- terminator explicitly.
130 Update (Item => Pointer,
131 Offset => 0,
132 Chars => Chars,
133 Check => False);
134 Poke (nul, into => Pointer + size_t'(Chars'Length));
135 end if;
137 return Pointer;
138 end New_Char_Array;
140 ----------------
141 -- New_String --
142 ----------------
144 function New_String (Str : String) return chars_ptr is
145 begin
146 return New_Char_Array (To_C (Str));
147 end New_String;
149 ----------
150 -- Peek --
151 ----------
153 function Peek (From : chars_ptr) return char is
154 begin
155 return char (From.all);
156 end Peek;
158 ----------
159 -- Poke --
160 ----------
162 procedure Poke (Value : char; Into : chars_ptr) is
163 begin
164 Into.all := Character (Value);
165 end Poke;
167 ---------------------
168 -- Position_Of_Nul --
169 ---------------------
171 function Position_Of_Nul (Into : char_array) return size_t is
172 begin
173 for J in Into'Range loop
174 if Into (J) = nul then
175 return J;
176 end if;
177 end loop;
179 return Into'Last + 1;
180 end Position_Of_Nul;
182 ------------
183 -- Strlen --
184 ------------
186 function Strlen (Item : chars_ptr) return size_t is
187 Item_Index : size_t := 0;
189 begin
190 if Item = Null_Ptr then
191 raise Dereference_Error;
192 end if;
194 loop
195 if Peek (Item + Item_Index) = nul then
196 return Item_Index;
197 end if;
199 Item_Index := Item_Index + 1;
200 end loop;
201 end Strlen;
203 ------------------
204 -- To_Chars_Ptr --
205 ------------------
207 function To_Chars_Ptr
208 (Item : char_array_access;
209 Nul_Check : Boolean := False) return chars_ptr
211 begin
212 if Item = null then
213 return Null_Ptr;
214 elsif Nul_Check
215 and then Position_Of_Nul (Into => Item.all) > Item'Last
216 then
217 raise Terminator_Error;
218 else
219 return To_chars_ptr (Item (Item'First)'Address);
220 end if;
221 end To_Chars_Ptr;
223 ------------
224 -- Update --
225 ------------
227 procedure Update
228 (Item : chars_ptr;
229 Offset : size_t;
230 Chars : char_array;
231 Check : Boolean := True)
233 Index : chars_ptr := Item + Offset;
235 begin
236 if Check and then Offset + Chars'Length > Strlen (Item) then
237 raise Update_Error;
238 end if;
240 for J in Chars'Range loop
241 Poke (Chars (J), Into => Index);
242 Index := Index + size_t'(1);
243 end loop;
244 end Update;
246 procedure Update
247 (Item : chars_ptr;
248 Offset : size_t;
249 Str : String;
250 Check : Boolean := True)
252 begin
253 -- Note: in RM 95, the Append_Nul => False parameter is omitted. But
254 -- this has the unintended consequence of truncating the string after
255 -- an update. As discussed in Ada 2005 AI-242, this was unintended,
256 -- and should be corrected. Since this is a clear error, it seems
257 -- appropriate to apply the correction in Ada 95 mode as well.
259 Update (Item, Offset, To_C (Str, Append_Nul => False), Check);
260 end Update;
262 -----------
263 -- Value --
264 -----------
266 function Value (Item : chars_ptr) return char_array is
267 Result : char_array (0 .. Strlen (Item));
269 begin
270 if Item = Null_Ptr then
271 raise Dereference_Error;
272 end if;
274 -- Note that the following loop will also copy the terminating Nul
276 for J in Result'Range loop
277 Result (J) := Peek (Item + J);
278 end loop;
280 return Result;
281 end Value;
283 function Value
284 (Item : chars_ptr;
285 Length : size_t) return char_array
287 begin
288 if Item = Null_Ptr then
289 raise Dereference_Error;
290 end if;
292 -- ACATS cxb3010 checks that Constraint_Error gets raised when Length
293 -- is 0. Seems better to check that Length is not null before declaring
294 -- an array with size_t bounds of 0 .. Length - 1 anyway.
296 if Length = 0 then
297 raise Constraint_Error;
298 end if;
300 declare
301 Result : char_array (0 .. Length - 1);
303 begin
304 for J in Result'Range loop
305 Result (J) := Peek (Item + J);
307 if Result (J) = nul then
308 return Result (0 .. J);
309 end if;
310 end loop;
312 return Result;
313 end;
314 end Value;
316 function Value (Item : chars_ptr) return String is
317 begin
318 return To_Ada (Value (Item));
319 end Value;
321 function Value (Item : chars_ptr; Length : size_t) return String is
322 Result : char_array (0 .. Length);
324 begin
325 -- As per AI-00177, this is equivalent to
326 -- To_Ada (Value (Item, Length) & nul);
328 if Item = Null_Ptr then
329 raise Dereference_Error;
330 end if;
332 for J in 0 .. Length - 1 loop
333 Result (J) := Peek (Item + J);
335 if Result (J) = nul then
336 return To_Ada (Result (0 .. J));
337 end if;
338 end loop;
340 Result (Length) := nul;
341 return To_Ada (Result);
342 end Value;
344 end Interfaces.C.Strings;