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DEFINITIONS
This source file includes following definitions.
- xrealloc
- xnrealloc
- x2realloc
- x2nrealloc
- xmemdup
/* xalloc.h -- malloc with out-of-memory checking
Copyright (C) 1990-2000, 2003-2004, 2006-2011 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef XALLOC_H_
# define XALLOC_H_
# include <stddef.h>
# include "xalloc-oversized.h"
# ifdef __cplusplus
extern "C" {
# endif
# if __GNUC__ >= 3
# define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
# else
# define _GL_ATTRIBUTE_MALLOC
# endif
# if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
# define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
# else
# define _GL_ATTRIBUTE_ALLOC_SIZE(args)
# endif
/* This function is always triggered when memory is exhausted.
It must be defined by the application, either explicitly
or by using gnulib's xalloc-die module. This is the
function to call when one wants the program to die because of a
memory allocation failure. */
extern _Noreturn void xalloc_die (void);
void *xmalloc (size_t s)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
void *xzalloc (size_t s)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
void *xcalloc (size_t n, size_t s)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
void *xrealloc (void *p, size_t s)
_GL_ATTRIBUTE_ALLOC_SIZE ((2));
void *x2realloc (void *p, size_t *pn);
void *xmemdup (void const *p, size_t s)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2));
char *xstrdup (char const *str)
_GL_ATTRIBUTE_MALLOC;
/* In the following macros, T must be an elementary or structure/union or
typedef'ed type, or a pointer to such a type. To apply one of the
following macros to a function pointer or array type, you need to typedef
it first and use the typedef name. */
/* Allocate an object of type T dynamically, with error checking. */
/* extern t *XMALLOC (typename t); */
# define XMALLOC(t) ((t *) xmalloc (sizeof (t)))
/* Allocate memory for N elements of type T, with error checking. */
/* extern t *XNMALLOC (size_t n, typename t); */
# define XNMALLOC(n, t) \
((t *) (sizeof (t) == 1 ? xmalloc (n) : xnmalloc (n, sizeof (t))))
/* Allocate an object of type T dynamically, with error checking,
and zero it. */
/* extern t *XZALLOC (typename t); */
# define XZALLOC(t) ((t *) xzalloc (sizeof (t)))
/* Allocate memory for N elements of type T, with error checking,
and zero it. */
/* extern t *XCALLOC (size_t n, typename t); */
# define XCALLOC(n, t) \
((t *) (sizeof (t) == 1 ? xzalloc (n) : xcalloc (n, sizeof (t))))
# if HAVE_INLINE
# define static_inline static inline
# else
void *xnmalloc (size_t n, size_t s)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
void *xnrealloc (void *p, size_t n, size_t s)
_GL_ATTRIBUTE_ALLOC_SIZE ((2, 3));
void *x2nrealloc (void *p, size_t *pn, size_t s);
char *xcharalloc (size_t n)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
# endif
# ifdef static_inline
/* Allocate an array of N objects, each with S bytes of memory,
dynamically, with error checking. S must be nonzero. */
static_inline void *xnmalloc (size_t n, size_t s)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
static_inline void *
xnmalloc (size_t n, size_t s)
{
if (xalloc_oversized (n, s))
xalloc_die ();
return xmalloc (n * s);
}
/* Change the size of an allocated block of memory P to an array of N
objects each of S bytes, with error checking. S must be nonzero. */
static_inline void *xnrealloc (void *p, size_t n, size_t s)
_GL_ATTRIBUTE_ALLOC_SIZE ((2, 3));
static_inline void *
xnrealloc (void *p, size_t n, size_t s)
{
if (xalloc_oversized (n, s))
xalloc_die ();
return xrealloc (p, n * s);
}
/* If P is null, allocate a block of at least *PN such objects;
otherwise, reallocate P so that it contains more than *PN objects
each of S bytes. *PN must be nonzero unless P is null, and S must
be nonzero. Set *PN to the new number of objects, and return the
pointer to the new block. *PN is never set to zero, and the
returned pointer is never null.
Repeated reallocations are guaranteed to make progress, either by
allocating an initial block with a nonzero size, or by allocating a
larger block.
In the following implementation, nonzero sizes are increased by a
factor of approximately 1.5 so that repeated reallocations have
O(N) overall cost rather than O(N**2) cost, but the
specification for this function does not guarantee that rate.
Here is an example of use:
int *p = NULL;
size_t used = 0;
size_t allocated = 0;
void
append_int (int value)
{
if (used == allocated)
p = x2nrealloc (p, &allocated, sizeof *p);
p[used++] = value;
}
This causes x2nrealloc to allocate a block of some nonzero size the
first time it is called.
To have finer-grained control over the initial size, set *PN to a
nonzero value before calling this function with P == NULL. For
example:
int *p = NULL;
size_t used = 0;
size_t allocated = 0;
size_t allocated1 = 1000;
void
append_int (int value)
{
if (used == allocated)
{
p = x2nrealloc (p, &allocated1, sizeof *p);
allocated = allocated1;
}
p[used++] = value;
}
*/
static_inline void *
x2nrealloc (void *p, size_t *pn, size_t s)
{
size_t n = *pn;
if (! p)
{
if (! n)
{
/* The approximate size to use for initial small allocation
requests, when the invoking code specifies an old size of
zero. This is the largest "small" request for the GNU C
library malloc. */
enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };
n = DEFAULT_MXFAST / s;
n += !n;
}
}
else
{
/* Set N = ceil (1.5 * N) so that progress is made if N == 1.
Check for overflow, so that N * S stays in size_t range.
The check is slightly conservative, but an exact check isn't
worth the trouble. */
if ((size_t) -1 / 3 * 2 / s <= n)
xalloc_die ();
n += (n + 1) / 2;
}
*pn = n;
return xrealloc (p, n * s);
}
/* Return a pointer to a new buffer of N bytes. This is like xmalloc,
except it returns char *. */
static_inline char *xcharalloc (size_t n)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
static_inline char *
xcharalloc (size_t n)
{
return XNMALLOC (n, char);
}
# endif
# ifdef __cplusplus
}
/* C++ does not allow conversions from void * to other pointer types
without a cast. Use templates to work around the problem when
possible. */
template <typename T> inline T *
xrealloc (T *p, size_t s)
{
return (T *) xrealloc ((void *) p, s);
}
template <typename T> inline T *
xnrealloc (T *p, size_t n, size_t s)
{
return (T *) xnrealloc ((void *) p, n, s);
}
template <typename T> inline T *
x2realloc (T *p, size_t *pn)
{
return (T *) x2realloc ((void *) p, pn);
}
template <typename T> inline T *
x2nrealloc (T *p, size_t *pn, size_t s)
{
return (T *) x2nrealloc ((void *) p, pn, s);
}
template <typename T> inline T *
xmemdup (T const *p, size_t s)
{
return (T *) xmemdup ((void const *) p, s);
}
# endif
#endif /* !XALLOC_H_ */