xref: /freebsd/contrib/diff/lib/xalloc.h (revision 3bdf775801b218aa5a89564839405b122f4b233e)
1 /* xalloc.h -- malloc with out-of-memory checking
2 
3    Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
4    1999, 2000, 2003 Free Software Foundation, Inc.
5 
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)
9    any later version.
10 
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.
15 
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.  */
19 
20 #ifndef XALLOC_H_
21 # define XALLOC_H_
22 
23 # include <stddef.h>
24 
25 # ifndef __attribute__
26 #  if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__
27 #   define __attribute__(x)
28 #  endif
29 # endif
30 
31 # ifndef ATTRIBUTE_NORETURN
32 #  define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
33 # endif
34 
35 /* If this pointer is non-zero, run the specified function upon each
36    allocation failure.  It is initialized to zero. */
37 extern void (*xalloc_fail_func) (void);
38 
39 /* If XALLOC_FAIL_FUNC is undefined or a function that returns, this
40    message is output.  It is translated via gettext.
41    Its value is "memory exhausted".  */
42 extern char const xalloc_msg_memory_exhausted[];
43 
44 /* This function is always triggered when memory is exhausted.  It is
45    in charge of honoring the two previous items.  It exits with status
46    exit_failure (defined in exitfail.h).  This is the
47    function to call when one wants the program to die because of a
48    memory allocation failure.  */
49 extern void xalloc_die (void) ATTRIBUTE_NORETURN;
50 
51 void *xmalloc (size_t s);
52 void *xnmalloc (size_t n, size_t s);
53 void *xzalloc (size_t s);
54 void *xcalloc (size_t n, size_t s);
55 void *xrealloc (void *p, size_t s);
56 void *xnrealloc (void *p, size_t n, size_t s);
57 void *x2realloc (void *p, size_t *pn);
58 void *x2nrealloc (void *p, size_t *pn, size_t s);
59 void *xclone (void const *p, size_t s);
60 char *xstrdup (const char *str);
61 
62 /* Return 1 if an array of N objects, each of size S, cannot exist due
63    to size arithmetic overflow.  S must be positive and N must be
64    nonnegative.  This is a macro, not an inline function, so that it
65    works correctly even when SIZE_MAX < N.
66 
67    By gnulib convention, SIZE_MAX represents overflow in size
68    calculations, so the conservative dividend to use here is
69    SIZE_MAX - 1, since SIZE_MAX might represent an overflowed value.
70    However, malloc (SIZE_MAX) fails on all known hosts where
71    sizeof (ptrdiff_t) <= sizeof (size_t), so do not bother to test for
72    exactly-SIZE_MAX allocations on such hosts; this avoids a test and
73    branch when S is known to be 1.  */
74 # define xalloc_oversized(n, s) \
75     ((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n))
76 
77 /* These macros are deprecated; they will go away soon, and are retained
78    temporarily only to ease conversion to the functions described above.  */
79 # define CCLONE(p, n) xclone (p, (n) * sizeof *(p))
80 # define CLONE(p) xclone (p, sizeof *(p))
81 # define NEW(type, var) type *var = xmalloc (sizeof (type))
82 # define XCALLOC(type, n) xcalloc (n, sizeof (type))
83 # define XMALLOC(type, n) xnmalloc (n, sizeof (type))
84 # define XREALLOC(p, type, n) xnrealloc (p, n, sizeof (type))
85 # define XFREE(p) free (p)
86 
87 #endif /* !XALLOC_H_ */
88