1 /* xalloc.h -- malloc with out-of-memory checking
3 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4 2000, 2003, 2004, 2006, 2007, 2008, 2009, 2010 Free Software Foundation,
7 This program is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
31 # ifndef __attribute__
32 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
33 # define __attribute__(x)
37 # ifndef ATTRIBUTE_NORETURN
38 # define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
41 # ifndef ATTRIBUTE_MALLOC
43 # define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
45 # define ATTRIBUTE_MALLOC
49 /* This function is always triggered when memory is exhausted.
50 It must be defined by the application, either explicitly
51 or by using gnulib's xalloc-die module. This is the
52 function to call when one wants the program to die because of a
53 memory allocation failure. */
54 extern void xalloc_die (void) ATTRIBUTE_NORETURN;
56 void *xmalloc (size_t s) ATTRIBUTE_MALLOC;
57 void *xzalloc (size_t s) ATTRIBUTE_MALLOC;
58 void *xcalloc (size_t n, size_t s) ATTRIBUTE_MALLOC;
59 void *xrealloc (void *p, size_t s);
60 void *x2realloc (void *p, size_t *pn);
61 void *xmemdup (void const *p, size_t s) ATTRIBUTE_MALLOC;
62 char *xstrdup (char const *str) ATTRIBUTE_MALLOC;
64 /* Return 1 if an array of N objects, each of size S, cannot exist due
65 to size arithmetic overflow. S must be positive and N must be
66 nonnegative. This is a macro, not an inline function, so that it
67 works correctly even when SIZE_MAX < N.
69 By gnulib convention, SIZE_MAX represents overflow in size
70 calculations, so the conservative dividend to use here is
71 SIZE_MAX - 1, since SIZE_MAX might represent an overflowed value.
72 However, malloc (SIZE_MAX) fails on all known hosts where
73 sizeof (ptrdiff_t) <= sizeof (size_t), so do not bother to test for
74 exactly-SIZE_MAX allocations on such hosts; this avoids a test and
75 branch when S is known to be 1. */
76 # define xalloc_oversized(n, s) \
77 ((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n))
80 /* In the following macros, T must be an elementary or structure/union or
81 typedef'ed type, or a pointer to such a type. To apply one of the
82 following macros to a function pointer or array type, you need to typedef
83 it first and use the typedef name. */
85 /* Allocate an object of type T dynamically, with error checking. */
86 /* extern t *XMALLOC (typename t); */
87 # define XMALLOC(t) ((t *) xmalloc (sizeof (t)))
89 /* Allocate memory for N elements of type T, with error checking. */
90 /* extern t *XNMALLOC (size_t n, typename t); */
91 # define XNMALLOC(n, t) \
92 ((t *) (sizeof (t) == 1 ? xmalloc (n) : xnmalloc (n, sizeof (t))))
94 /* Allocate an object of type T dynamically, with error checking,
96 /* extern t *XZALLOC (typename t); */
97 # define XZALLOC(t) ((t *) xzalloc (sizeof (t)))
99 /* Allocate memory for N elements of type T, with error checking,
101 /* extern t *XCALLOC (size_t n, typename t); */
102 # define XCALLOC(n, t) \
103 ((t *) (sizeof (t) == 1 ? xzalloc (n) : xcalloc (n, sizeof (t))))
106 * Gawk uses this file only to keep dfa.c happy.
107 * We're therefore safe in manually defining HAVE_INLINE to
108 * make the !@#$%^&*() thing just work.
111 #define HAVE_INLINE 1 /* so there. nyah, nyah, nyah. */
115 # define static_inline static inline
117 void *xnmalloc (size_t n, size_t s) ATTRIBUTE_MALLOC;
118 void *xnrealloc (void *p, size_t n, size_t s);
119 void *x2nrealloc (void *p, size_t *pn, size_t s);
120 char *xcharalloc (size_t n) ATTRIBUTE_MALLOC;
123 # ifdef static_inline
125 /* Allocate an array of N objects, each with S bytes of memory,
126 dynamically, with error checking. S must be nonzero. */
128 static_inline void *xnmalloc (size_t n, size_t s) ATTRIBUTE_MALLOC;
130 xnmalloc (size_t n, size_t s)
132 if (xalloc_oversized (n, s))
134 return xmalloc (n * s);
139 /* Allocate an array of N objects, each with S bytes of memory,
140 dynamically, with error checking. S must be nonzero.
141 Clear the contents afterwards. */
144 xcalloc(size_t nmemb, size_t size)
146 void *p = xmalloc (nmemb * size);
147 memset(p, '\0', nmemb * size);
151 /* Reallocate a pointer to a new size, with error checking. */
154 xrealloc(void *p, size_t size)
156 void *new_p = realloc(p, size);
163 /* xalloc_die --- fatal error message when malloc fails, needed by dfa.c */
168 extern void r_fatal(const char *msg, ...) ATTRIBUTE_NORETURN ;
170 r_fatal(_("xalloc: malloc failed: %s"), strerror(errno));
174 /* Change the size of an allocated block of memory P to an array of N
175 objects each of S bytes, with error checking. S must be nonzero. */
178 xnrealloc (void *p, size_t n, size_t s)
180 if (xalloc_oversized (n, s))
182 return xrealloc (p, n * s);
185 /* If P is null, allocate a block of at least *PN such objects;
186 otherwise, reallocate P so that it contains more than *PN objects
187 each of S bytes. *PN must be nonzero unless P is null, and S must
188 be nonzero. Set *PN to the new number of objects, and return the
189 pointer to the new block. *PN is never set to zero, and the
190 returned pointer is never null.
192 Repeated reallocations are guaranteed to make progress, either by
193 allocating an initial block with a nonzero size, or by allocating a
196 In the following implementation, nonzero sizes are increased by a
197 factor of approximately 1.5 so that repeated reallocations have
198 O(N) overall cost rather than O(N**2) cost, but the
199 specification for this function does not guarantee that rate.
201 Here is an example of use:
205 size_t allocated = 0;
208 append_int (int value)
210 if (used == allocated)
211 p = x2nrealloc (p, &allocated, sizeof *p);
215 This causes x2nrealloc to allocate a block of some nonzero size the
216 first time it is called.
218 To have finer-grained control over the initial size, set *PN to a
219 nonzero value before calling this function with P == NULL. For
224 size_t allocated = 0;
225 size_t allocated1 = 1000;
228 append_int (int value)
230 if (used == allocated)
232 p = x2nrealloc (p, &allocated1, sizeof *p);
233 allocated = allocated1;
241 x2nrealloc (void *p, size_t *pn, size_t s)
249 /* The approximate size to use for initial small allocation
250 requests, when the invoking code specifies an old size of
251 zero. 64 bytes is the largest "small" request for the
252 GNU C library malloc. */
253 enum { DEFAULT_MXFAST = 64 };
255 n = DEFAULT_MXFAST / s;
261 /* Set N = ceil (1.5 * N) so that progress is made if N == 1.
262 Check for overflow, so that N * S stays in size_t range.
263 The check is slightly conservative, but an exact check isn't
264 worth the trouble. */
265 if ((size_t) -1 / 3 * 2 / s <= n)
271 return xrealloc (p, n * s);
274 /* Return a pointer to a new buffer of N bytes. This is like xmalloc,
275 except it returns char *. */
277 static_inline char *xcharalloc (size_t n) ATTRIBUTE_MALLOC;
279 xcharalloc (size_t n)
281 return XNMALLOC (n, char);
284 /* Allocate S bytes of zeroed memory dynamically, with error checking.
285 There's no need for xnzalloc (N, S), since it would be equivalent
286 to xcalloc (N, S). */
291 return memset (xmalloc (s), 0, s);
299 /* C++ does not allow conversions from void * to other pointer types
300 without a cast. Use templates to work around the problem when
303 template <typename T> inline T *
304 xrealloc (T *p, size_t s)
306 return (T *) xrealloc ((void *) p, s);
309 template <typename T> inline T *
310 xnrealloc (T *p, size_t n, size_t s)
312 return (T *) xnrealloc ((void *) p, n, s);
315 template <typename T> inline T *
316 x2realloc (T *p, size_t *pn)
318 return (T *) x2realloc ((void *) p, pn);
321 template <typename T> inline T *
322 x2nrealloc (T *p, size_t *pn, size_t s)
324 return (T *) x2nrealloc ((void *) p, pn, s);
327 template <typename T> inline T *
328 xmemdup (T const *p, size_t s)
330 return (T *) xmemdup ((void const *) p, s);
336 #endif /* !XALLOC_H_ */