1 /* xalloc.h -- malloc with out-of-memory checking
2
3 Copyright (C) 1990-2000, 2003-2004, 2006-2012 Free Software Foundation, Inc.
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17
18 #ifndef XALLOC_H_
19 #define XALLOC_H_
20
21 #include <stddef.h>
22
23 #include "xalloc-oversized.h"
24
25 _GL_INLINE_HEADER_BEGIN
26 #ifndef XALLOC_INLINE
27 # define XALLOC_INLINE _GL_INLINE
28 #endif
29
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33
34
35 #if __GNUC__ >= 3
36 # define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
37 #else
38 # define _GL_ATTRIBUTE_MALLOC
39 #endif
40
41 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
42 # define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
43 #else
44 # define _GL_ATTRIBUTE_ALLOC_SIZE(args)
45 #endif
46
47 /* This function is always triggered when memory is exhausted.
48 It must be defined by the application, either explicitly
49 or by using gnulib's xalloc-die module. This is the
50 function to call when one wants the program to die because of a
51 memory allocation failure. */
52 extern _Noreturn void xalloc_die (void);
53
54 void *xmalloc (size_t s)
55 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
56 void *xzalloc (size_t s)
57 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
58 void *xcalloc (size_t n, size_t s)
59 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
60 void *xrealloc (void *p, size_t s)
61 _GL_ATTRIBUTE_ALLOC_SIZE ((2));
62 void *x2realloc (void *p, size_t *pn);
63 void *xmemdup (void const *p, size_t s)
64 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2));
65 char *xstrdup (char const *str)
66 _GL_ATTRIBUTE_MALLOC;
67
68 /* In the following macros, T must be an elementary or structure/union or
69 typedef'ed type, or a pointer to such a type. To apply one of the
70 following macros to a function pointer or array type, you need to typedef
71 it first and use the typedef name. */
72
73 /* Allocate an object of type T dynamically, with error checking. */
74 /* extern t *XMALLOC (typename t); */
75 #define XMALLOC(t) ((t *) xmalloc (sizeof (t)))
76
77 /* Allocate memory for N elements of type T, with error checking. */
78 /* extern t *XNMALLOC (size_t n, typename t); */
79 #define XNMALLOC(n, t) \
80 ((t *) (sizeof (t) == 1 ? xmalloc (n) : xnmalloc (n, sizeof (t))))
81
82 /* Allocate an object of type T dynamically, with error checking,
83 and zero it. */
84 /* extern t *XZALLOC (typename t); */
85 #define XZALLOC(t) ((t *) xzalloc (sizeof (t)))
86
87 /* Allocate memory for N elements of type T, with error checking,
88 and zero it. */
89 /* extern t *XCALLOC (size_t n, typename t); */
90 #define XCALLOC(n, t) \
91 ((t *) (sizeof (t) == 1 ? xzalloc (n) : xcalloc (n, sizeof (t))))
92
93
94 /* Allocate an array of N objects, each with S bytes of memory,
95 dynamically, with error checking. S must be nonzero. */
96
97 XALLOC_INLINE void *xnmalloc (size_t n, size_t s)
98 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
99 XALLOC_INLINE void *
xnmalloc(size_t n,size_t s)100 xnmalloc (size_t n, size_t s)
101 {
102 if (xalloc_oversized (n, s))
103 xalloc_die ();
104 return xmalloc (n * s);
105 }
106
107 /* Change the size of an allocated block of memory P to an array of N
108 objects each of S bytes, with error checking. S must be nonzero. */
109
110 XALLOC_INLINE void *xnrealloc (void *p, size_t n, size_t s)
111 _GL_ATTRIBUTE_ALLOC_SIZE ((2, 3));
112 XALLOC_INLINE void *
xnrealloc(void * p,size_t n,size_t s)113 xnrealloc (void *p, size_t n, size_t s)
114 {
115 if (xalloc_oversized (n, s))
116 xalloc_die ();
117 return xrealloc (p, n * s);
118 }
119
120 /* If P is null, allocate a block of at least *PN such objects;
121 otherwise, reallocate P so that it contains more than *PN objects
122 each of S bytes. *PN must be nonzero unless P is null, and S must
123 be nonzero. Set *PN to the new number of objects, and return the
124 pointer to the new block. *PN is never set to zero, and the
125 returned pointer is never null.
126
127 Repeated reallocations are guaranteed to make progress, either by
128 allocating an initial block with a nonzero size, or by allocating a
129 larger block.
130
131 In the following implementation, nonzero sizes are increased by a
132 factor of approximately 1.5 so that repeated reallocations have
133 O(N) overall cost rather than O(N**2) cost, but the
134 specification for this function does not guarantee that rate.
135
136 Here is an example of use:
137
138 int *p = NULL;
139 size_t used = 0;
140 size_t allocated = 0;
141
142 void
143 append_int (int value)
144 {
145 if (used == allocated)
146 p = x2nrealloc (p, &allocated, sizeof *p);
147 p[used++] = value;
148 }
149
150 This causes x2nrealloc to allocate a block of some nonzero size the
151 first time it is called.
152
153 To have finer-grained control over the initial size, set *PN to a
154 nonzero value before calling this function with P == NULL. For
155 example:
156
157 int *p = NULL;
158 size_t used = 0;
159 size_t allocated = 0;
160 size_t allocated1 = 1000;
161
162 void
163 append_int (int value)
164 {
165 if (used == allocated)
166 {
167 p = x2nrealloc (p, &allocated1, sizeof *p);
168 allocated = allocated1;
169 }
170 p[used++] = value;
171 }
172
173 */
174
175 XALLOC_INLINE void *
x2nrealloc(void * p,size_t * pn,size_t s)176 x2nrealloc (void *p, size_t *pn, size_t s)
177 {
178 size_t n = *pn;
179
180 if (! p)
181 {
182 if (! n)
183 {
184 /* The approximate size to use for initial small allocation
185 requests, when the invoking code specifies an old size of
186 zero. This is the largest "small" request for the GNU C
187 library malloc. */
188 enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };
189
190 n = DEFAULT_MXFAST / s;
191 n += !n;
192 }
193 }
194 else
195 {
196 /* Set N = ceil (1.5 * N) so that progress is made if N == 1.
197 Check for overflow, so that N * S stays in size_t range.
198 The check is slightly conservative, but an exact check isn't
199 worth the trouble. */
200 if ((size_t) -1 / 3 * 2 / s <= n)
201 xalloc_die ();
202 n += (n + 1) / 2;
203 }
204
205 *pn = n;
206 return xrealloc (p, n * s);
207 }
208
209 /* Return a pointer to a new buffer of N bytes. This is like xmalloc,
210 except it returns char *. */
211
212 XALLOC_INLINE char *xcharalloc (size_t n)
213 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
214 XALLOC_INLINE char *
xcharalloc(size_t n)215 xcharalloc (size_t n)
216 {
217 return XNMALLOC (n, char);
218 }
219
220 #ifdef __cplusplus
221 }
222
223 /* C++ does not allow conversions from void * to other pointer types
224 without a cast. Use templates to work around the problem when
225 possible. */
226
227 template <typename T> inline T *
xrealloc(T * p,size_t s)228 xrealloc (T *p, size_t s)
229 {
230 return (T *) xrealloc ((void *) p, s);
231 }
232
233 template <typename T> inline T *
xnrealloc(T * p,size_t n,size_t s)234 xnrealloc (T *p, size_t n, size_t s)
235 {
236 return (T *) xnrealloc ((void *) p, n, s);
237 }
238
239 template <typename T> inline T *
x2realloc(T * p,size_t * pn)240 x2realloc (T *p, size_t *pn)
241 {
242 return (T *) x2realloc ((void *) p, pn);
243 }
244
245 template <typename T> inline T *
x2nrealloc(T * p,size_t * pn,size_t s)246 x2nrealloc (T *p, size_t *pn, size_t s)
247 {
248 return (T *) x2nrealloc ((void *) p, pn, s);
249 }
250
251 template <typename T> inline T *
xmemdup(T const * p,size_t s)252 xmemdup (T const *p, size_t s)
253 {
254 return (T *) xmemdup ((void const *) p, s);
255 }
256
257 #endif
258
259
260 #endif /* !XALLOC_H_ */
261