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diff --git a/gl/xalloc.h b/gl/xalloc.h
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+++ b/gl/xalloc.h
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+/* xalloc.h -- malloc with out-of-memory checking
+
+   Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+   1999, 2000, 2003, 2004, 2006 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 2, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#ifndef XALLOC_H_
+# define XALLOC_H_
+
+# include <stddef.h>
+
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+
+# ifndef __attribute__
+#  if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__
+#   define __attribute__(x)
+#  endif
+# endif
+
+# ifndef ATTRIBUTE_NORETURN
+#  define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+# 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 void xalloc_die (void) ATTRIBUTE_NORETURN;
+
+void *xmalloc (size_t s);
+void *xzalloc (size_t s);
+void *xcalloc (size_t n, size_t s);
+void *xrealloc (void *p, size_t s);
+void *x2realloc (void *p, size_t *pn);
+void *xmemdup (void const *p, size_t s);
+char *xstrdup (char const *str);
+
+/* Return 1 if an array of N objects, each of size S, cannot exist due
+   to size arithmetic overflow.  S must be positive and N must be
+   nonnegative.  This is a macro, not an inline function, so that it
+   works correctly even when SIZE_MAX < N.
+
+   By gnulib convention, SIZE_MAX represents overflow in size
+   calculations, so the conservative dividend to use here is
+   SIZE_MAX - 1, since SIZE_MAX might represent an overflowed value.
+   However, malloc (SIZE_MAX) fails on all known hosts where
+   sizeof (ptrdiff_t) <= sizeof (size_t), so do not bother to test for
+   exactly-SIZE_MAX allocations on such hosts; this avoids a test and
+   branch when S is known to be 1.  */
+# define xalloc_oversized(n, s) \
+    ((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n))
+
+
+/* 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);
+   void *xnrealloc (void *p, size_t n, size_t s);
+   void *x2nrealloc (void *p, size_t *pn, size_t s);
+   char *xcharalloc (size_t n);
+# 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)
+{
+  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)
+{
+  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 doubled so that
+   repeated reallocations have O(N log N) overall cost rather than
+   O(N**2) cost, but the specification for this function does not
+   guarantee that sizes are doubled.
+
+   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.  64 bytes is the largest "small" request for the
+             GNU C library malloc.  */
+          enum { DEFAULT_MXFAST = 64 };
+
+          n = DEFAULT_MXFAST / s;
+          n += !n;
+        }
+    }
+  else
+    {
+      if (((size_t) -1) / 2 / s < n)
+        xalloc_die ();
+      n *= 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)
+{
+  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_ */