1 /* xmalloc.c -- malloc with out of memory checking
3 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 2003,
4 1999, 2000, 2002, 2003 Free Software Foundation, Inc.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software Foundation,
18 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
31 #define _(msgid) gettext (msgid)
32 #define N_(msgid) msgid
38 # define SIZE_MAX ((size_t) -1)
42 "you must run the autoconf test for a GNU libc compatible malloc"
46 "you must run the autoconf test for a GNU libc compatible realloc"
49 /* If non NULL, call this function when memory is exhausted. */
50 void (*xalloc_fail_func) (void) = 0;
52 /* Return true if array of N objects, each of size S, cannot exist due
53 to arithmetic overflow. S must be nonzero. */
56 array_size_overflow (size_t n, size_t s)
58 return SIZE_MAX / s < n;
61 /* If XALLOC_FAIL_FUNC is NULL, or does return, display this message
62 before exiting when memory is exhausted. Goes through gettext. */
63 char const xalloc_msg_memory_exhausted[] = N_("memory exhausted");
69 (*xalloc_fail_func) ();
70 error (exit_failure, 0, "%s", _(xalloc_msg_memory_exhausted));
71 /* The `noreturn' cannot be given to error, since it may return if
72 its first argument is 0. To help compilers understand the
73 xalloc_die does terminate, call abort. */
77 /* Allocate an array of N objects, each with S bytes of memory,
78 dynamically, with error checking. S must be nonzero. */
81 xnmalloc_inline (size_t n, size_t s)
84 if (array_size_overflow (n, s) || ! (p = malloc (n * s)))
90 xnmalloc (size_t n, size_t s)
92 return xnmalloc_inline (n, s);
95 /* Allocate N bytes of memory dynamically, with error checking. */
100 return xnmalloc_inline (n, 1);
103 /* Change the size of an allocated block of memory P to an array of N
104 objects each of S bytes, with error checking. S must be nonzero. */
107 xnrealloc_inline (void *p, size_t n, size_t s)
109 if (array_size_overflow (n, s) || ! (p = realloc (p, n * s)))
115 xnrealloc (void *p, size_t n, size_t s)
117 return xnrealloc_inline (p, n, s);
120 /* Change the size of an allocated block of memory P to N bytes,
121 with error checking. */
124 xrealloc (void *p, size_t n)
126 return xnrealloc_inline (p, n, 1);
130 /* If P is null, allocate a block of at least *PN such objects;
131 otherwise, reallocate P so that it contains more than *PN objects
132 each of S bytes. *PN must be nonzero unless P is null, and S must
133 be nonzero. Set *PN to the new number of objects, and return the
134 pointer to the new block. *PN is never set to zero, and the
135 returned pointer is never null.
137 Repeated reallocations are guaranteed to make progress, either by
138 allocating an initial block with a nonzero size, or by allocating a
141 In the following implementation, nonzero sizes are doubled so that
142 repeated reallocations have O(N log N) overall cost rather than
143 O(N**2) cost, but the specification for this function does not
144 guarantee that sizes are doubled.
146 Here is an example of use:
153 append_int (int value)
155 if (used == allocated)
156 p = x2nrealloc (p, &allocated, sizeof *p);
160 This causes x2nrealloc to allocate a block of some nonzero size the
161 first time it is called.
163 To have finer-grained control over the initial size, set *PN to a
164 nonzero value before calling this function with P == NULL. For
170 size allocated1 = 1000;
173 append_int (int value)
175 if (used == allocated)
177 p = x2nrealloc (p, &allocated1, sizeof *p);
178 allocated = allocated1;
186 x2nrealloc_inline (void *p, size_t *pn, size_t s)
194 /* The approximate size to use for initial small allocation
195 requests, when the invoking code specifies an old size of
196 zero. 64 bytes is the largest "small" request for the
197 GNU C library malloc. */
198 enum { DEFAULT_MXFAST = 64 };
200 n = DEFAULT_MXFAST / s;
206 if (SIZE_MAX / 2 / s < n)
212 return xrealloc (p, n * s);
216 x2nrealloc (void *p, size_t *pn, size_t s)
218 return x2nrealloc_inline (p, pn, s);
221 /* If P is null, allocate a block of at least *PN bytes; otherwise,
222 reallocate P so that it contains more than *PN bytes. *PN must be
223 nonzero unless P is null. Set *PN to the new block's size, and
224 return the pointer to the new block. *PN is never set to zero, and
225 the returned pointer is never null. */
228 x2realloc (void *p, size_t *pn)
230 return x2nrealloc_inline (p, pn, 1);
233 /* Allocate S bytes of zeroed memory dynamically, with error checking.
234 There's no need for xnzalloc (N, S), since it would be equivalent
235 to xcalloc (N, S). */
240 return memset (xmalloc (s), 0, s);
243 /* Allocate zeroed memory for N elements of S bytes, with error
244 checking. S must be nonzero. */
247 xcalloc (size_t n, size_t s)
250 /* Test for overflow, since some calloc implementations don't have
251 proper overflow checks. */
252 if (array_size_overflow (n, s) || ! (p = calloc (n, s)))
257 /* Clone an object P of size S, with error checking. There's no need
258 for xnclone (P, N, S), since xclone (P, N * S) works without any
259 need for an arithmetic overflow check. */
262 xclone (void const *p, size_t s)
264 return memcpy (xmalloc (s), p, s);