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262 lines
7.5 KiB
C++
262 lines
7.5 KiB
C++
/* xalloc.h -- malloc with out-of-memory checking
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Copyright (C) 1990-2000, 2003-2004, 2006-2020 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 3 of the License, or
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(at your option) 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, see <https://www.gnu.org/licenses/>. */
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#ifndef XALLOC_H_
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#define XALLOC_H_
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#include <stddef.h>
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#include <stdint.h>
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#include "xalloc-oversized.h"
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#ifndef _GL_INLINE_HEADER_BEGIN
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#error "Please include config.h first."
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#endif
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_GL_INLINE_HEADER_BEGIN
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#ifndef XALLOC_INLINE
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# define XALLOC_INLINE _GL_INLINE
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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#if ! defined __clang__ && \
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(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
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# define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
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#else
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# define _GL_ATTRIBUTE_ALLOC_SIZE(args)
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#endif
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/* This function is always triggered when memory is exhausted.
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It must be defined by the application, either explicitly
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or by using gnulib's xalloc-die module. This is the
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function to call when one wants the program to die because of a
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memory allocation failure. */
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extern _Noreturn void xalloc_die (void);
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void *xmalloc (size_t s)
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_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
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void *xzalloc (size_t s)
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_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
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void *xcalloc (size_t n, size_t s)
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_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
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void *xrealloc (void *p, size_t s)
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_GL_ATTRIBUTE_ALLOC_SIZE ((2));
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void *x2realloc (void *p, size_t *pn);
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void *xmemdup (void const *p, size_t s)
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_GL_ATTRIBUTE_ALLOC_SIZE ((2));
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char *xstrdup (char const *str)
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_GL_ATTRIBUTE_MALLOC;
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/* In the following macros, T must be an elementary or structure/union or
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typedef'ed type, or a pointer to such a type. To apply one of the
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following macros to a function pointer or array type, you need to typedef
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it first and use the typedef name. */
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/* Allocate an object of type T dynamically, with error checking. */
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/* extern t *XMALLOC (typename t); */
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#define XMALLOC(t) ((t *) xmalloc (sizeof (t)))
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/* Allocate memory for N elements of type T, with error checking. */
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/* extern t *XNMALLOC (size_t n, typename t); */
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#define XNMALLOC(n, t) \
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((t *) (sizeof (t) == 1 ? xmalloc (n) : xnmalloc (n, sizeof (t))))
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/* Allocate an object of type T dynamically, with error checking,
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and zero it. */
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/* extern t *XZALLOC (typename t); */
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#define XZALLOC(t) ((t *) xzalloc (sizeof (t)))
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/* Allocate memory for N elements of type T, with error checking,
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and zero it. */
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/* extern t *XCALLOC (size_t n, typename t); */
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#define XCALLOC(n, t) \
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((t *) (sizeof (t) == 1 ? xzalloc (n) : xcalloc (n, sizeof (t))))
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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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XALLOC_INLINE void *xnmalloc (size_t n, size_t s)
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_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
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XALLOC_INLINE void *
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xnmalloc (size_t n, size_t s)
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{
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if (xalloc_oversized (n, s))
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xalloc_die ();
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return xmalloc (n * s);
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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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XALLOC_INLINE void *xnrealloc (void *p, size_t n, size_t s)
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_GL_ATTRIBUTE_ALLOC_SIZE ((2, 3));
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XALLOC_INLINE void *
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xnrealloc (void *p, size_t n, size_t s)
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{
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if (xalloc_oversized (n, s))
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xalloc_die ();
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return xrealloc (p, n * s);
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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. S must be nonzero. Set *PN to the new number of
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objects, and return the pointer to the new block. *PN is never set
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to zero, and the 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 increased by a
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factor of approximately 1.5 so that repeated reallocations have
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O(N) overall cost rather than O(N**2) cost, but the
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specification for this function does not guarantee that rate.
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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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XALLOC_INLINE void *
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x2nrealloc (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. This is the largest "small" request for the GNU C
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library malloc. */
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enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };
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n = DEFAULT_MXFAST / s;
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n += !n;
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}
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if (xalloc_oversized (n, s))
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xalloc_die ();
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}
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else
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{
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/* Set N = floor (1.5 * N) + 1 so that progress is made even if N == 0.
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Check for overflow, so that N * S stays in both ptrdiff_t and
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size_t range. The check may be slightly conservative, but an
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exact check isn't worth the trouble. */
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if ((PTRDIFF_MAX < SIZE_MAX ? PTRDIFF_MAX : SIZE_MAX) / 3 * 2 / s
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<= n)
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xalloc_die ();
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n += n / 2 + 1;
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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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/* Return a pointer to a new buffer of N bytes. This is like xmalloc,
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except it returns char *. */
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XALLOC_INLINE char *xcharalloc (size_t n)
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_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
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XALLOC_INLINE char *
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xcharalloc (size_t n)
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{
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return XNMALLOC (n, char);
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}
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#ifdef __cplusplus
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}
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/* C++ does not allow conversions from void * to other pointer types
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without a cast. Use templates to work around the problem when
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possible. */
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template <typename T> inline T *
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xrealloc (T *p, size_t s)
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{
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return (T *) xrealloc ((void *) p, s);
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}
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template <typename T> inline T *
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xnrealloc (T *p, size_t n, size_t s)
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{
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return (T *) xnrealloc ((void *) p, n, s);
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}
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template <typename T> inline T *
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x2realloc (T *p, size_t *pn)
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{
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return (T *) x2realloc ((void *) p, pn);
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}
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template <typename T> inline T *
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x2nrealloc (T *p, size_t *pn, size_t s)
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{
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return (T *) x2nrealloc ((void *) p, pn, s);
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}
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template <typename T> inline T *
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xmemdup (T const *p, size_t s)
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{
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return (T *) xmemdup ((void const *) p, s);
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}
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#endif
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_GL_INLINE_HEADER_END
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#endif /* !XALLOC_H_ */
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