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));
173 /* Clone an object P of size S, with error checking. There's no need
174 for xnmemdup (P, N, S), since xmemdup (P, N * S) works without any
175 need for an arithmetic overflow check. */
178 xmemdup (void const *p, size_t s)
180 return memcpy (xmalloc (s), p, s);
184 /* Change the size of an allocated block of memory P to an array of N
185 objects each of S bytes, with error checking. S must be nonzero. */
188 xnrealloc (void *p, size_t n, size_t s)
190 if (xalloc_oversized (n, s))
192 return xrealloc (p, n * s);
195 /* If P is null, allocate a block of at least *PN such objects;
196 otherwise, reallocate P so that it contains more than *PN objects
197 each of S bytes. *PN must be nonzero unless P is null, and S must
198 be nonzero. Set *PN to the new number of objects, and return the
199 pointer to the new block. *PN is never set to zero, and the
200 returned pointer is never null.
202 Repeated reallocations are guaranteed to make progress, either by
203 allocating an initial block with a nonzero size, or by allocating a
206 In the following implementation, nonzero sizes are increased by a
207 factor of approximately 1.5 so that repeated reallocations have
208 O(N) overall cost rather than O(N**2) cost, but the
209 specification for this function does not guarantee that rate.
211 Here is an example of use:
215 size_t allocated = 0;
218 append_int (int value)
220 if (used == allocated)
221 p = x2nrealloc (p, &allocated, sizeof *p);
225 This causes x2nrealloc to allocate a block of some nonzero size the
226 first time it is called.
228 To have finer-grained control over the initial size, set *PN to a
229 nonzero value before calling this function with P == NULL. For
234 size_t allocated = 0;
235 size_t allocated1 = 1000;
238 append_int (int value)
240 if (used == allocated)
242 p = x2nrealloc (p, &allocated1, sizeof *p);
243 allocated = allocated1;
251 x2nrealloc (void *p, size_t *pn, size_t s)
259 /* The approximate size to use for initial small allocation
260 requests, when the invoking code specifies an old size of
261 zero. 64 bytes is the largest "small" request for the
262 GNU C library malloc. */
263 enum { DEFAULT_MXFAST = 64 };
265 n = DEFAULT_MXFAST / s;
271 /* Set N = ceil (1.5 * N) so that progress is made if N == 1.
272 Check for overflow, so that N * S stays in size_t range.
273 The check is slightly conservative, but an exact check isn't
274 worth the trouble. */
275 if ((size_t) -1 / 3 * 2 / s <= n)
281 return xrealloc (p, n * s);
284 /* Return a pointer to a new buffer of N bytes. This is like xmalloc,
285 except it returns char *. */
287 static_inline char *xcharalloc (size_t n) ATTRIBUTE_MALLOC;
289 xcharalloc (size_t n)
291 return XNMALLOC (n, char);
294 /* Allocate S bytes of zeroed memory dynamically, with error checking.
295 There's no need for xnzalloc (N, S), since it would be equivalent
296 to xcalloc (N, S). */
301 return memset (xmalloc (s), 0, s);
309 /* C++ does not allow conversions from void * to other pointer types
310 without a cast. Use templates to work around the problem when
313 template <typename T> inline T *
314 xrealloc (T *p, size_t s)
316 return (T *) xrealloc ((void *) p, s);
319 template <typename T> inline T *
320 xnrealloc (T *p, size_t n, size_t s)
322 return (T *) xnrealloc ((void *) p, n, s);
325 template <typename T> inline T *
326 x2realloc (T *p, size_t *pn)
328 return (T *) x2realloc ((void *) p, pn);
331 template <typename T> inline T *
332 x2nrealloc (T *p, size_t *pn, size_t s)
334 return (T *) x2nrealloc ((void *) p, pn, s);
337 template <typename T> inline T *
338 xmemdup (T const *p, size_t s)
340 return (T *) xmemdup ((void const *) p, s);
346 #endif /* !XALLOC_H_ */