xmalloc.c revision 05436638acc7c010349a69c3395f1a57c642dc62 
1/* xmalloc.c -- malloc with out of memory checking
2
3   Copyright (C) 1990-2000, 2002-2006, 2008-2012 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#include <config.h>
19
20#define XALLOC_INLINE _GL_EXTERN_INLINE
21
22#include "xalloc.h"
23
24#include <stdlib.h>
25#include <string.h>
26
27/* 1 if calloc is known to be compatible with GNU calloc.  This
28   matters if we are not also using the calloc module, which defines
29   HAVE_CALLOC_GNU and supports the GNU API even on non-GNU platforms.  */
30#if defined HAVE_CALLOC_GNU || (defined __GLIBC__ && !defined __UCLIBC__)
31enum { HAVE_GNU_CALLOC = 1 };
32#else
33enum { HAVE_GNU_CALLOC = 0 };
34#endif
35
36/* Allocate N bytes of memory dynamically, with error checking.  */
37
38void *
39xmalloc (size_t n)
40{
41  void *p = malloc (n);
42  if (!p && n != 0)
43    xalloc_die ();
44  return p;
45}
46
47/* Change the size of an allocated block of memory P to N bytes,
48   with error checking.  */
49
50void *
51xrealloc (void *p, size_t n)
52{
53  if (!n && p)
54    {
55      /* The GNU and C99 realloc behaviors disagree here.  Act like
56         GNU, even if the underlying realloc is C99.  */
57      free (p);
58      return NULL;
59    }
60
61  p = realloc (p, n);
62  if (!p && n)
63    xalloc_die ();
64  return p;
65}
66
67/* If P is null, allocate a block of at least *PN bytes; otherwise,
68   reallocate P so that it contains more than *PN bytes.  *PN must be
69   nonzero unless P is null.  Set *PN to the new block's size, and
70   return the pointer to the new block.  *PN is never set to zero, and
71   the returned pointer is never null.  */
72
73void *
74x2realloc (void *p, size_t *pn)
75{
76  return x2nrealloc (p, pn, 1);
77}
78
79/* Allocate S bytes of zeroed memory dynamically, with error checking.
80   There's no need for xnzalloc (N, S), since it would be equivalent
81   to xcalloc (N, S).  */
82
83void *
84xzalloc (size_t s)
85{
86  return memset (xmalloc (s), 0, s);
87}
88
89/* Allocate zeroed memory for N elements of S bytes, with error
90   checking.  S must be nonzero.  */
91
92void *
93xcalloc (size_t n, size_t s)
94{
95  void *p;
96  /* Test for overflow, since some calloc implementations don't have
97     proper overflow checks.  But omit overflow and size-zero tests if
98     HAVE_GNU_CALLOC, since GNU calloc catches overflow and never
99     returns NULL if successful.  */
100  if ((! HAVE_GNU_CALLOC && xalloc_oversized (n, s))
101      || (! (p = calloc (n, s)) && (HAVE_GNU_CALLOC || n != 0)))
102    xalloc_die ();
103  return p;
104}
105
106/* Clone an object P of size S, with error checking.  There's no need
107   for xnmemdup (P, N, S), since xmemdup (P, N * S) works without any
108   need for an arithmetic overflow check.  */
109
110void *
111xmemdup (void const *p, size_t s)
112{
113  return memcpy (xmalloc (s), p, s);
114}
115
116/* Clone STRING.  */
117
118char *
119xstrdup (char const *string)
120{
121  return xmemdup (string, strlen (string) + 1);
122}
123