230 lines
5.6 KiB
C
230 lines
5.6 KiB
C
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/* xmalloc.c -- malloc with out of memory checking
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Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
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1999, 2000, 2002, 2003, 2004 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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#if HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include "xalloc.h"
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#include <stdlib.h>
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#include <string.h>
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#ifndef SIZE_MAX
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# define SIZE_MAX ((size_t) -1)
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#endif
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/* Allocate an array of N objects, each with S bytes of memory,
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dynamically, with error checking. S must be nonzero. */
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static inline void *
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xnmalloc_inline (size_t n, size_t s)
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{
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void *p;
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if (xalloc_oversized (n, s) || (! (p = malloc (n * s)) && n != 0))
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xalloc_die ();
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return p;
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}
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void *
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xnmalloc (size_t n, size_t s)
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{
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return xnmalloc_inline (n, s);
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}
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/* Allocate N bytes of memory dynamically, with error checking. */
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void *
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xmalloc (size_t n)
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{
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return xnmalloc_inline (n, 1);
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}
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/* Change the size of an allocated block of memory P to an array of N
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objects each of S bytes, with error checking. S must be nonzero. */
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static inline void *
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xnrealloc_inline (void *p, size_t n, size_t s)
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{
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if (xalloc_oversized (n, s) || (! (p = realloc (p, n * s)) && n != 0))
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xalloc_die ();
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return p;
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}
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void *
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xnrealloc (void *p, size_t n, size_t s)
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{
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return xnrealloc_inline (p, n, s);
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}
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/* Change the size of an allocated block of memory P to N bytes,
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with error checking. */
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void *
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xrealloc (void *p, size_t n)
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{
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return xnrealloc_inline (p, n, 1);
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}
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/* If P is null, allocate a block of at least *PN such objects;
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otherwise, reallocate P so that it contains more than *PN objects
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each of S bytes. *PN must be nonzero unless P is null, and S must
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be nonzero. Set *PN to the new number of objects, and return the
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pointer to the new block. *PN is never set to zero, and the
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returned pointer is never null.
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Repeated reallocations are guaranteed to make progress, either by
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allocating an initial block with a nonzero size, or by allocating a
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larger block.
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In the following implementation, nonzero sizes are doubled so that
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repeated reallocations have O(N log N) overall cost rather than
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O(N**2) cost, but the specification for this function does not
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guarantee that sizes are doubled.
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Here is an example of use:
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int *p = NULL;
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size_t used = 0;
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size_t allocated = 0;
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void
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append_int (int value)
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{
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if (used == allocated)
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p = x2nrealloc (p, &allocated, sizeof *p);
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p[used++] = value;
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}
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This causes x2nrealloc to allocate a block of some nonzero size the
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first time it is called.
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To have finer-grained control over the initial size, set *PN to a
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nonzero value before calling this function with P == NULL. For
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example:
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int *p = NULL;
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size_t used = 0;
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size_t allocated = 0;
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size_t allocated1 = 1000;
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void
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append_int (int value)
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{
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if (used == allocated)
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{
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p = x2nrealloc (p, &allocated1, sizeof *p);
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allocated = allocated1;
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}
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p[used++] = value;
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}
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*/
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static inline void *
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x2nrealloc_inline (void *p, size_t *pn, size_t s)
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{
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size_t n = *pn;
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if (! p)
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{
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if (! n)
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{
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/* The approximate size to use for initial small allocation
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requests, when the invoking code specifies an old size of
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zero. 64 bytes is the largest "small" request for the
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GNU C library malloc. */
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enum { DEFAULT_MXFAST = 64 };
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n = DEFAULT_MXFAST / s;
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n += !n;
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}
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}
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else
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{
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if (SIZE_MAX / 2 / s < n)
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xalloc_die ();
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n *= 2;
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}
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*pn = n;
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return xrealloc (p, n * s);
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}
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void *
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x2nrealloc (void *p, size_t *pn, size_t s)
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{
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return x2nrealloc_inline (p, pn, s);
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}
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/* If P is null, allocate a block of at least *PN bytes; otherwise,
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reallocate P so that it contains more than *PN bytes. *PN must be
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nonzero unless P is null. Set *PN to the new block's size, and
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return the pointer to the new block. *PN is never set to zero, and
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the returned pointer is never null. */
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void *
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x2realloc (void *p, size_t *pn)
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{
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return x2nrealloc_inline (p, pn, 1);
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}
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/* Allocate S bytes of zeroed memory dynamically, with error checking.
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There's no need for xnzalloc (N, S), since it would be equivalent
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to xcalloc (N, S). */
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void *
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xzalloc (size_t s)
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{
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return memset (xmalloc (s), 0, s);
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}
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/* Allocate zeroed memory for N elements of S bytes, with error
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checking. S must be nonzero. */
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void *
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xcalloc (size_t n, size_t s)
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{
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void *p;
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/* Test for overflow, since some calloc implementations don't have
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proper overflow checks. */
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if (xalloc_oversized (n, s) || (! (p = calloc (n, s)) && n != 0))
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xalloc_die ();
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return p;
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}
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/* Clone an object P of size S, with error checking. There's no need
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for xnmemdup (P, N, S), since xmemdup (P, N * S) works without any
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need for an arithmetic overflow check. */
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void *
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xmemdup (void const *p, size_t s)
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{
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return memcpy (xmalloc (s), p, s);
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}
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/* Clone STRING. */
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char *
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xstrdup (char const *string)
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{
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return xmemdup (string, strlen (string) + 1);
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}
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