1/* realloc() function that is glibc compatible.
2
3   Copyright (C) 1997, 2003, 2004, 2006, 2007, 2009 Free Software
4   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 3 of the License, or
9   (at your option) 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, see <http://www.gnu.org/licenses/>.  */
18
19/* written by Jim Meyering and Bruno Haible */
20
21#include <config.h>
22
23/* Only the AC_FUNC_REALLOC macro defines 'realloc' already in config.h.  */
24#ifdef realloc
25# define NEED_REALLOC_GNU 1
26#endif
27
28/* Infer the properties of the system's malloc function.
29   Only the AC_FUNC_MALLOC macro defines 'malloc' already in config.h.  */
30#if GNULIB_MALLOC_GNU && !defined malloc
31# define SYSTEM_MALLOC_GLIBC_COMPATIBLE 1
32#endif
33
34/* Below we want to call the system's malloc and realloc.
35   Undefine the symbols here so that including <stdlib.h> provides a
36   declaration of malloc(), not of rpl_malloc(), and likewise for realloc.  */
37#undef malloc
38#undef realloc
39
40/* Specification.  */
41#include <stdlib.h>
42
43#include <errno.h>
44
45/* Below we want to call the system's malloc and realloc.
46   Undefine the symbols, if they were defined by gnulib's <stdlib.h>
47   replacement.  */
48#undef malloc
49#undef realloc
50
51/* Change the size of an allocated block of memory P to N bytes,
52   with error checking.  If N is zero, change it to 1.  If P is NULL,
53   use malloc.  */
54
55void *
56rpl_realloc (void *p, size_t n)
57{
58  void *result;
59
60#if NEED_REALLOC_GNU
61  if (n == 0)
62    {
63      n = 1;
64
65      /* In theory realloc might fail, so don't rely on it to free.  */
66      free (p);
67      p = NULL;
68    }
69#endif
70
71  if (p == NULL)
72    {
73#if GNULIB_REALLOC_GNU && !NEED_REALLOC_GNU && !SYSTEM_MALLOC_GLIBC_COMPATIBLE
74      if (n == 0)
75	n = 1;
76#endif
77      result = malloc (n);
78    }
79  else
80    result = realloc (p, n);
81
82#if !HAVE_REALLOC_POSIX
83  if (result == NULL)
84    errno = ENOMEM;
85#endif
86
87  return result;
88}
89