1 /* xalloc.h -- malloc with out-of-memory checking
2
3 Copyright (C) 1990-2000, 2003-2004, 2006-2014 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 #ifndef _GL_INLINE_HEADER_BEGIN
26 #error "Please include config.h first."
27 #endif
28 _GL_INLINE_HEADER_BEGIN
29 #ifndef XALLOC_INLINE
30 # define XALLOC_INLINE _GL_INLINE
31 #endif
32
33 #ifdef __cplusplus
34 extern "C" {
35 #endif
36
37
38 #if __GNUC__ >= 3
39 # define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
40 #else
41 # define _GL_ATTRIBUTE_MALLOC
42 #endif
43
44 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
45 # define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
46 #else
47 # define _GL_ATTRIBUTE_ALLOC_SIZE(args)
48 #endif
49
50 /* This function is always triggered when memory is exhausted.
51 It must be defined by the application, either explicitly
52 or by using gnulib's xalloc-die module. This is the
53 function to call when one wants the program to die because of a
54 memory allocation failure. */
55 extern _Noreturn void xalloc_die (void);
56
57 void *xmalloc (size_t s)
58 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
59 void *xzalloc (size_t s)
60 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
61 void *xcalloc (size_t n, size_t s)
62 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
63 void *xrealloc (void *p, size_t s)
64 _GL_ATTRIBUTE_ALLOC_SIZE ((2));
65 void *x2realloc (void *p, size_t *pn);
66 void *xmemdup (void const *p, size_t s)
67 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2));
68 char *xstrdup (char const *str)
69 _GL_ATTRIBUTE_MALLOC;
70
71 /* In the following macros, T must be an elementary or structure/union or
72 typedef'ed type, or a pointer to such a type. To apply one of the
73 following macros to a function pointer or array type, you need to typedef
74 it first and use the typedef name. */
75
76 /* Allocate an object of type T dynamically, with error checking. */
77 /* extern t *XMALLOC (typename t); */
78 #define XMALLOC(t) ((t *) xmalloc (sizeof (t)))
79
80 /* Allocate memory for N elements of type T, with error checking. */
81 /* extern t *XNMALLOC (size_t n, typename t); */
82 #define XNMALLOC(n, t) \
83 ((t *) (sizeof (t) == 1 ? xmalloc (n) : xnmalloc (n, sizeof (t))))
84
85 /* Allocate an object of type T dynamically, with error checking,
86 and zero it. */
87 /* extern t *XZALLOC (typename t); */
88 #define XZALLOC(t) ((t *) xzalloc (sizeof (t)))
89
90 /* Allocate memory for N elements of type T, with error checking,
91 and zero it. */
92 /* extern t *XCALLOC (size_t n, typename t); */
93 #define XCALLOC(n, t) \
94 ((t *) (sizeof (t) == 1 ? xzalloc (n) : xcalloc (n, sizeof (t))))
95
96
97 /* Allocate an array of N objects, each with S bytes of memory,
98 dynamically, with error checking. S must be nonzero. */
99
100 XALLOC_INLINE void *xnmalloc (size_t n, size_t s)
101 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
102 XALLOC_INLINE void *
xnmalloc(size_t n,size_t s)103 xnmalloc (size_t n, size_t s)
104 {
105 if (xalloc_oversized (n, s))
106 xalloc_die ();
107 return xmalloc (n * s);
108 }
109
110 /* Change the size of an allocated block of memory P to an array of N
111 objects each of S bytes, with error checking. S must be nonzero. */
112
113 XALLOC_INLINE void *xnrealloc (void *p, size_t n, size_t s)
114 _GL_ATTRIBUTE_ALLOC_SIZE ((2, 3));
115 XALLOC_INLINE void *
xnrealloc(void * p,size_t n,size_t s)116 xnrealloc (void *p, size_t n, size_t s)
117 {
118 if (xalloc_oversized (n, s))
119 xalloc_die ();
120 return xrealloc (p, n * s);
121 }
122
123 /* If P is null, allocate a block of at least *PN such objects;
124 otherwise, reallocate P so that it contains more than *PN objects
125 each of S bytes. *PN must be nonzero unless P is null, and S must
126 be nonzero. Set *PN to the new number of objects, and return the
127 pointer to the new block. *PN is never set to zero, and the
128 returned pointer is never null.
129
130 Repeated reallocations are guaranteed to make progress, either by
131 allocating an initial block with a nonzero size, or by allocating a
132 larger block.
133
134 In the following implementation, nonzero sizes are increased by a
135 factor of approximately 1.5 so that repeated reallocations have
136 O(N) overall cost rather than O(N**2) cost, but the
137 specification for this function does not guarantee that rate.
138
139 Here is an example of use:
140
141 int *p = NULL;
142 size_t used = 0;
143 size_t allocated = 0;
144
145 void
146 append_int (int value)
147 {
148 if (used == allocated)
149 p = x2nrealloc (p, &allocated, sizeof *p);
150 p[used++] = value;
151 }
152
153 This causes x2nrealloc to allocate a block of some nonzero size the
154 first time it is called.
155
156 To have finer-grained control over the initial size, set *PN to a
157 nonzero value before calling this function with P == NULL. For
158 example:
159
160 int *p = NULL;
161 size_t used = 0;
162 size_t allocated = 0;
163 size_t allocated1 = 1000;
164
165 void
166 append_int (int value)
167 {
168 if (used == allocated)
169 {
170 p = x2nrealloc (p, &allocated1, sizeof *p);
171 allocated = allocated1;
172 }
173 p[used++] = value;
174 }
175
176 */
177
178 XALLOC_INLINE void *
x2nrealloc(void * p,size_t * pn,size_t s)179 x2nrealloc (void *p, size_t *pn, size_t s)
180 {
181 size_t n = *pn;
182
183 if (! p)
184 {
185 if (! n)
186 {
187 /* The approximate size to use for initial small allocation
188 requests, when the invoking code specifies an old size of
189 zero. This is the largest "small" request for the GNU C
190 library malloc. */
191 enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };
192
193 n = DEFAULT_MXFAST / s;
194 n += !n;
195 }
196 }
197 else
198 {
199 /* Set N = ceil (1.5 * N) so that progress is made if N == 1.
200 Check for overflow, so that N * S stays in size_t range.
201 The check is slightly conservative, but an exact check isn't
202 worth the trouble. */
203 if ((size_t) -1 / 3 * 2 / s <= n)
204 xalloc_die ();
205 n += (n + 1) / 2;
206 }
207
208 *pn = n;
209 return xrealloc (p, n * s);
210 }
211
212 /* Return a pointer to a new buffer of N bytes. This is like xmalloc,
213 except it returns char *. */
214
215 XALLOC_INLINE char *xcharalloc (size_t n)
216 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
217 XALLOC_INLINE char *
xcharalloc(size_t n)218 xcharalloc (size_t n)
219 {
220 return XNMALLOC (n, char);
221 }
222
223 #ifdef __cplusplus
224 }
225
226 /* C++ does not allow conversions from void * to other pointer types
227 without a cast. Use templates to work around the problem when
228 possible. */
229
230 template <typename T> inline T *
xrealloc(T * p,size_t s)231 xrealloc (T *p, size_t s)
232 {
233 return (T *) xrealloc ((void *) p, s);
234 }
235
236 template <typename T> inline T *
xnrealloc(T * p,size_t n,size_t s)237 xnrealloc (T *p, size_t n, size_t s)
238 {
239 return (T *) xnrealloc ((void *) p, n, s);
240 }
241
242 template <typename T> inline T *
x2realloc(T * p,size_t * pn)243 x2realloc (T *p, size_t *pn)
244 {
245 return (T *) x2realloc ((void *) p, pn);
246 }
247
248 template <typename T> inline T *
x2nrealloc(T * p,size_t * pn,size_t s)249 x2nrealloc (T *p, size_t *pn, size_t s)
250 {
251 return (T *) x2nrealloc ((void *) p, pn, s);
252 }
253
254 template <typename T> inline T *
xmemdup(T const * p,size_t s)255 xmemdup (T const *p, size_t s)
256 {
257 return (T *) xmemdup ((void const *) p, s);
258 }
259
260 #endif
261
262
263 #endif /* !XALLOC_H_ */
264