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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 17:47:50 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 17:47:50 +0000
commitbbe35a6e1b54ef5cd7c1c471886c30ba85c0804e (patch)
tree985a31e8c860c690d9f20e6621ce5fcc05ccd244 /lib/malloc
parentInitial commit. (diff)
downloadwget-bbe35a6e1b54ef5cd7c1c471886c30ba85c0804e.tar.xz
wget-bbe35a6e1b54ef5cd7c1c471886c30ba85c0804e.zip
Adding upstream version 1.21.upstream/1.21upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--lib/malloc.c56
-rw-r--r--lib/malloc/scratch_buffer.h151
-rw-r--r--lib/malloc/scratch_buffer_dupfree.c41
-rw-r--r--lib/malloc/scratch_buffer_grow.c56
-rw-r--r--lib/malloc/scratch_buffer_grow_preserve.c67
-rw-r--r--lib/malloc/scratch_buffer_set_array_size.c64
-rw-r--r--lib/malloca.c105
-rw-r--r--lib/malloca.h123
8 files changed, 663 insertions, 0 deletions
diff --git a/lib/malloc.c b/lib/malloc.c
new file mode 100644
index 0000000..7232f1e
--- /dev/null
+++ b/lib/malloc.c
@@ -0,0 +1,56 @@
+/* malloc() function that is glibc compatible.
+
+ Copyright (C) 1997-1998, 2006-2007, 2009-2020 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, 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 <https://www.gnu.org/licenses/>. */
+
+/* written by Jim Meyering and Bruno Haible */
+
+#define _GL_USE_STDLIB_ALLOC 1
+#include <config.h>
+/* Only the AC_FUNC_MALLOC macro defines 'malloc' already in config.h. */
+#ifdef malloc
+# define NEED_MALLOC_GNU 1
+# undef malloc
+/* Whereas the gnulib module 'malloc-gnu' defines HAVE_MALLOC_GNU. */
+#elif GNULIB_MALLOC_GNU && !HAVE_MALLOC_GNU
+# define NEED_MALLOC_GNU 1
+#endif
+
+#include <stdlib.h>
+
+#include <errno.h>
+
+/* Allocate an N-byte block of memory from the heap.
+ If N is zero, allocate a 1-byte block. */
+
+void *
+rpl_malloc (size_t n)
+{
+ void *result;
+
+#if NEED_MALLOC_GNU
+ if (n == 0)
+ n = 1;
+#endif
+
+ result = malloc (n);
+
+#if !HAVE_MALLOC_POSIX
+ if (result == NULL)
+ errno = ENOMEM;
+#endif
+
+ return result;
+}
diff --git a/lib/malloc/scratch_buffer.h b/lib/malloc/scratch_buffer.h
new file mode 100644
index 0000000..6eca220
--- /dev/null
+++ b/lib/malloc/scratch_buffer.h
@@ -0,0 +1,151 @@
+/* Variable-sized buffer with on-stack default allocation.
+ Copyright (C) 2015-2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library 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.
+
+ The GNU C Library 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 the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _SCRATCH_BUFFER_H
+#define _SCRATCH_BUFFER_H
+
+/* Scratch buffers with a default stack allocation and fallback to
+ heap allocation. It is expected that this function is used in this
+ way:
+
+ struct scratch_buffer tmpbuf;
+ scratch_buffer_init (&tmpbuf);
+
+ while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length))
+ if (!scratch_buffer_grow (&tmpbuf))
+ return -1;
+
+ scratch_buffer_free (&tmpbuf);
+ return 0;
+
+ The allocation functions (scratch_buffer_grow,
+ scratch_buffer_grow_preserve, scratch_buffer_set_array_size) make
+ sure that the heap allocation, if any, is freed, so that the code
+ above does not have a memory leak. The buffer still remains in a
+ state that can be deallocated using scratch_buffer_free, so a loop
+ like this is valid as well:
+
+ struct scratch_buffer tmpbuf;
+ scratch_buffer_init (&tmpbuf);
+
+ while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length))
+ if (!scratch_buffer_grow (&tmpbuf))
+ break;
+
+ scratch_buffer_free (&tmpbuf);
+
+ scratch_buffer_grow and scratch_buffer_grow_preserve are guaranteed
+ to grow the buffer by at least 512 bytes. This means that when
+ using the scratch buffer as a backing store for a non-character
+ array whose element size, in bytes, is 512 or smaller, the scratch
+ buffer only has to grow once to make room for at least one more
+ element.
+*/
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+/* Scratch buffer. Must be initialized with scratch_buffer_init
+ before its use. */
+struct scratch_buffer {
+ void *data; /* Pointer to the beginning of the scratch area. */
+ size_t length; /* Allocated space at the data pointer, in bytes. */
+ union { max_align_t __align; char __c[1024]; } __space;
+};
+
+/* Initializes *BUFFER so that BUFFER->data points to BUFFER->__space
+ and BUFFER->length reflects the available space. */
+static inline void
+scratch_buffer_init (struct scratch_buffer *buffer)
+{
+ buffer->data = buffer->__space.__c;
+ buffer->length = sizeof (buffer->__space);
+}
+
+/* Deallocates *BUFFER (if it was heap-allocated). */
+static inline void
+scratch_buffer_free (struct scratch_buffer *buffer)
+{
+ if (buffer->data != buffer->__space.__c)
+ free (buffer->data);
+}
+
+/* Grow *BUFFER by some arbitrary amount. The buffer contents is NOT
+ preserved. Return true on success, false on allocation failure (in
+ which case the old buffer is freed). On success, the new buffer is
+ larger than the previous size. On failure, *BUFFER is deallocated,
+ but remains in a free-able state, and errno is set. */
+bool __libc_scratch_buffer_grow (struct scratch_buffer *buffer);
+libc_hidden_proto (__libc_scratch_buffer_grow)
+
+/* Alias for __libc_scratch_buffer_grow. */
+static __always_inline bool
+scratch_buffer_grow (struct scratch_buffer *buffer)
+{
+ return __glibc_likely (__libc_scratch_buffer_grow (buffer));
+}
+
+/* Like __libc_scratch_buffer_grow, but preserve the old buffer
+ contents on success, as a prefix of the new buffer. */
+bool __libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer);
+libc_hidden_proto (__libc_scratch_buffer_grow_preserve)
+
+/* Alias for __libc_scratch_buffer_grow_preserve. */
+static __always_inline bool
+scratch_buffer_grow_preserve (struct scratch_buffer *buffer)
+{
+ return __glibc_likely (__libc_scratch_buffer_grow_preserve (buffer));
+}
+
+/* Grow *BUFFER so that it can store at least NELEM elements of SIZE
+ bytes. The buffer contents are NOT preserved. Both NELEM and SIZE
+ can be zero. Return true on success, false on allocation failure
+ (in which case the old buffer is freed, but *BUFFER remains in a
+ free-able state, and errno is set). It is unspecified whether this
+ function can reduce the array size. */
+bool __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer,
+ size_t nelem, size_t size);
+libc_hidden_proto (__libc_scratch_buffer_set_array_size)
+
+/* Alias for __libc_scratch_set_array_size. */
+static __always_inline bool
+scratch_buffer_set_array_size (struct scratch_buffer *buffer,
+ size_t nelem, size_t size)
+{
+ return __glibc_likely (__libc_scratch_buffer_set_array_size
+ (buffer, nelem, size));
+}
+
+/* Return a copy of *BUFFER's first SIZE bytes as a heap-allocated block,
+ deallocating *BUFFER if it was heap-allocated. SIZE must be at
+ most *BUFFER's size. Return NULL (setting errno) on memory
+ exhaustion. */
+void *__libc_scratch_buffer_dupfree (struct scratch_buffer *buffer,
+ size_t size);
+libc_hidden_proto (__libc_scratch_buffer_dupfree)
+
+/* Alias for __libc_scratch_dupfree. */
+static __always_inline void *
+scratch_buffer_dupfree (struct scratch_buffer *buffer, size_t size)
+{
+ void *r = __libc_scratch_buffer_dupfree (buffer, size);
+ return __glibc_likely (r != NULL) ? r : NULL;
+}
+
+#endif /* _SCRATCH_BUFFER_H */
diff --git a/lib/malloc/scratch_buffer_dupfree.c b/lib/malloc/scratch_buffer_dupfree.c
new file mode 100644
index 0000000..e34336f
--- /dev/null
+++ b/lib/malloc/scratch_buffer_dupfree.c
@@ -0,0 +1,41 @@
+/* Variable-sized buffer with on-stack default allocation.
+ Copyright (C) 2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library 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.
+
+ The GNU C Library 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 the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
+#include <scratch_buffer.h>
+#include <string.h>
+
+void *
+__libc_scratch_buffer_dupfree (struct scratch_buffer *buffer, size_t size)
+{
+ void *data = buffer->data;
+ if (data == buffer->__space.__c)
+ {
+ void *copy = malloc (size);
+ return copy != NULL ? memcpy (copy, data, size) : NULL;
+ }
+ else
+ {
+ void *copy = realloc (data, size);
+ return copy != NULL ? copy : data;
+ }
+}
+libc_hidden_def (__libc_scratch_buffer_dupfree)
diff --git a/lib/malloc/scratch_buffer_grow.c b/lib/malloc/scratch_buffer_grow.c
new file mode 100644
index 0000000..41befe3
--- /dev/null
+++ b/lib/malloc/scratch_buffer_grow.c
@@ -0,0 +1,56 @@
+/* Variable-sized buffer with on-stack default allocation.
+ Copyright (C) 2015-2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library 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.
+
+ The GNU C Library 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 the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
+#include <scratch_buffer.h>
+#include <errno.h>
+
+bool
+__libc_scratch_buffer_grow (struct scratch_buffer *buffer)
+{
+ void *new_ptr;
+ size_t new_length = buffer->length * 2;
+
+ /* Discard old buffer. */
+ scratch_buffer_free (buffer);
+
+ /* Check for overflow. */
+ if (__glibc_likely (new_length >= buffer->length))
+ new_ptr = malloc (new_length);
+ else
+ {
+ __set_errno (ENOMEM);
+ new_ptr = NULL;
+ }
+
+ if (__glibc_unlikely (new_ptr == NULL))
+ {
+ /* Buffer must remain valid to free. */
+ scratch_buffer_init (buffer);
+ return false;
+ }
+
+ /* Install new heap-based buffer. */
+ buffer->data = new_ptr;
+ buffer->length = new_length;
+ return true;
+}
+libc_hidden_def (__libc_scratch_buffer_grow)
diff --git a/lib/malloc/scratch_buffer_grow_preserve.c b/lib/malloc/scratch_buffer_grow_preserve.c
new file mode 100644
index 0000000..aef2329
--- /dev/null
+++ b/lib/malloc/scratch_buffer_grow_preserve.c
@@ -0,0 +1,67 @@
+/* Variable-sized buffer with on-stack default allocation.
+ Copyright (C) 2015-2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library 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.
+
+ The GNU C Library 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 the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
+#include <scratch_buffer.h>
+#include <errno.h>
+#include <string.h>
+
+bool
+__libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer)
+{
+ size_t new_length = 2 * buffer->length;
+ void *new_ptr;
+
+ if (buffer->data == buffer->__space.__c)
+ {
+ /* Move buffer to the heap. No overflow is possible because
+ buffer->length describes a small buffer on the stack. */
+ new_ptr = malloc (new_length);
+ if (new_ptr == NULL)
+ return false;
+ memcpy (new_ptr, buffer->__space.__c, buffer->length);
+ }
+ else
+ {
+ /* Buffer was already on the heap. Check for overflow. */
+ if (__glibc_likely (new_length >= buffer->length))
+ new_ptr = realloc (buffer->data, new_length);
+ else
+ {
+ __set_errno (ENOMEM);
+ new_ptr = NULL;
+ }
+
+ if (__glibc_unlikely (new_ptr == NULL))
+ {
+ /* Deallocate, but buffer must remain valid to free. */
+ free (buffer->data);
+ scratch_buffer_init (buffer);
+ return false;
+ }
+ }
+
+ /* Install new heap-based buffer. */
+ buffer->data = new_ptr;
+ buffer->length = new_length;
+ return true;
+}
+libc_hidden_def (__libc_scratch_buffer_grow_preserve)
diff --git a/lib/malloc/scratch_buffer_set_array_size.c b/lib/malloc/scratch_buffer_set_array_size.c
new file mode 100644
index 0000000..5f5e4c2
--- /dev/null
+++ b/lib/malloc/scratch_buffer_set_array_size.c
@@ -0,0 +1,64 @@
+/* Variable-sized buffer with on-stack default allocation.
+ Copyright (C) 2015-2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library 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.
+
+ The GNU C Library 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 the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
+#include <scratch_buffer.h>
+#include <errno.h>
+#include <limits.h>
+
+bool
+__libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer,
+ size_t nelem, size_t size)
+{
+ size_t new_length = nelem * size;
+
+ /* Avoid overflow check if both values are small. */
+ if ((nelem | size) >> (sizeof (size_t) * CHAR_BIT / 2) != 0
+ && nelem != 0 && size != new_length / nelem)
+ {
+ /* Overflow. Discard the old buffer, but it must remain valid
+ to free. */
+ scratch_buffer_free (buffer);
+ scratch_buffer_init (buffer);
+ __set_errno (ENOMEM);
+ return false;
+ }
+
+ if (new_length <= buffer->length)
+ return true;
+
+ /* Discard old buffer. */
+ scratch_buffer_free (buffer);
+
+ char *new_ptr = malloc (new_length);
+ if (new_ptr == NULL)
+ {
+ /* Buffer must remain valid to free. */
+ scratch_buffer_init (buffer);
+ return false;
+ }
+
+ /* Install new heap-based buffer. */
+ buffer->data = new_ptr;
+ buffer->length = new_length;
+ return true;
+}
+libc_hidden_def (__libc_scratch_buffer_set_array_size)
diff --git a/lib/malloca.c b/lib/malloca.c
new file mode 100644
index 0000000..975b166
--- /dev/null
+++ b/lib/malloca.c
@@ -0,0 +1,105 @@
+/* Safe automatic memory allocation.
+ Copyright (C) 2003, 2006-2007, 2009-2020 Free Software Foundation, Inc.
+ Written by Bruno Haible <bruno@clisp.org>, 2003, 2018.
+
+ 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, 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 <https://www.gnu.org/licenses/>. */
+
+#define _GL_USE_STDLIB_ALLOC 1
+#include <config.h>
+
+/* Specification. */
+#include "malloca.h"
+
+#include "verify.h"
+
+/* The speed critical point in this file is freea() applied to an alloca()
+ result: it must be fast, to match the speed of alloca(). The speed of
+ mmalloca() and freea() in the other case are not critical, because they
+ are only invoked for big memory sizes.
+ Here we use a bit in the address as an indicator, an idea by Ondřej Bílka.
+ malloca() can return three types of pointers:
+ - Pointers ≡ 0 mod 2*sa_alignment_max come from stack allocation.
+ - Pointers ≡ sa_alignment_max mod 2*sa_alignment_max come from heap
+ allocation.
+ - NULL comes from a failed heap allocation. */
+
+/* Type for holding very small pointer differences. */
+typedef unsigned char small_t;
+/* Verify that it is wide enough. */
+verify (2 * sa_alignment_max - 1 <= (small_t) -1);
+
+void *
+mmalloca (size_t n)
+{
+#if HAVE_ALLOCA
+ /* Allocate one more word, used to determine the address to pass to freea(),
+ and room for the alignment ≡ sa_alignment_max mod 2*sa_alignment_max. */
+ size_t nplus = n + sizeof (small_t) + 2 * sa_alignment_max - 1;
+
+ if (nplus >= n)
+ {
+ char *mem = (char *) malloc (nplus);
+
+ if (mem != NULL)
+ {
+ char *p =
+ (char *)((((uintptr_t)mem + sizeof (small_t) + sa_alignment_max - 1)
+ & ~(uintptr_t)(2 * sa_alignment_max - 1))
+ + sa_alignment_max);
+ /* Here p >= mem + sizeof (small_t),
+ and p <= mem + sizeof (small_t) + 2 * sa_alignment_max - 1
+ hence p + n <= mem + nplus.
+ So, the memory range [p, p+n) lies in the allocated memory range
+ [mem, mem + nplus). */
+ ((small_t *) p)[-1] = p - mem;
+ /* p ≡ sa_alignment_max mod 2*sa_alignment_max. */
+ return p;
+ }
+ }
+ /* Out of memory. */
+ return NULL;
+#else
+# if !MALLOC_0_IS_NONNULL
+ if (n == 0)
+ n = 1;
+# endif
+ return malloc (n);
+#endif
+}
+
+#if HAVE_ALLOCA
+void
+freea (void *p)
+{
+ /* Check argument. */
+ if ((uintptr_t) p & (sa_alignment_max - 1))
+ {
+ /* p was not the result of a malloca() call. Invalid argument. */
+ abort ();
+ }
+ /* Determine whether p was a non-NULL pointer returned by mmalloca(). */
+ if ((uintptr_t) p & sa_alignment_max)
+ {
+ void *mem = (char *) p - ((small_t *) p)[-1];
+ free (mem);
+ }
+}
+#endif
+
+/*
+ * Hey Emacs!
+ * Local Variables:
+ * coding: utf-8
+ * End:
+ */
diff --git a/lib/malloca.h b/lib/malloca.h
new file mode 100644
index 0000000..ccc485a
--- /dev/null
+++ b/lib/malloca.h
@@ -0,0 +1,123 @@
+/* Safe automatic memory allocation.
+ Copyright (C) 2003-2007, 2009-2020 Free Software Foundation, Inc.
+ Written by Bruno Haible <bruno@clisp.org>, 2003.
+
+ 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, 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 <https://www.gnu.org/licenses/>. */
+
+#ifndef _MALLOCA_H
+#define _MALLOCA_H
+
+#include <alloca.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+#include "xalloc-oversized.h"
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/* safe_alloca(N) is equivalent to alloca(N) when it is safe to call
+ alloca(N); otherwise it returns NULL. It either returns N bytes of
+ memory allocated on the stack, that lasts until the function returns,
+ or NULL.
+ Use of safe_alloca should be avoided:
+ - inside arguments of function calls - undefined behaviour,
+ - in inline functions - the allocation may actually last until the
+ calling function returns.
+*/
+#if HAVE_ALLOCA
+/* The OS usually guarantees only one guard page at the bottom of the stack,
+ and a page size can be as small as 4096 bytes. So we cannot safely
+ allocate anything larger than 4096 bytes. Also care for the possibility
+ of a few compiler-allocated temporary stack slots.
+ This must be a macro, not a function. */
+# define safe_alloca(N) ((N) < 4032 ? alloca (N) : NULL)
+#else
+# define safe_alloca(N) ((void) (N), NULL)
+#endif
+
+/* malloca(N) is a safe variant of alloca(N). It allocates N bytes of
+ memory allocated on the stack, that must be freed using freea() before
+ the function returns. Upon failure, it returns NULL. */
+#if HAVE_ALLOCA
+# define malloca(N) \
+ ((N) < 4032 - (2 * sa_alignment_max - 1) \
+ ? (void *) (((uintptr_t) (char *) alloca ((N) + 2 * sa_alignment_max - 1) \
+ + (2 * sa_alignment_max - 1)) \
+ & ~(uintptr_t)(2 * sa_alignment_max - 1)) \
+ : mmalloca (N))
+#else
+# define malloca(N) \
+ mmalloca (N)
+#endif
+extern void * mmalloca (size_t n);
+
+/* Free a block of memory allocated through malloca(). */
+#if HAVE_ALLOCA
+extern void freea (void *p);
+#else
+# define freea free
+#endif
+
+/* nmalloca(N,S) is an overflow-safe variant of malloca (N * S).
+ It allocates an array of N objects, each with S bytes of memory,
+ on the stack. S must be positive and N must be nonnegative.
+ The array must be freed using freea() before the function returns. */
+#define nmalloca(n, s) (xalloc_oversized (n, s) ? NULL : malloca ((n) * (s)))
+
+
+#ifdef __cplusplus
+}
+#endif
+
+
+/* ------------------- Auxiliary, non-public definitions ------------------- */
+
+/* Determine the alignment of a type at compile time. */
+#if defined __GNUC__ || defined __clang__ || defined __IBM__ALIGNOF__
+# define sa_alignof __alignof__
+#elif defined __cplusplus
+ template <class type> struct sa_alignof_helper { char __slot1; type __slot2; };
+# define sa_alignof(type) offsetof (sa_alignof_helper<type>, __slot2)
+#elif defined __hpux
+ /* Work around a HP-UX 10.20 cc bug with enums constants defined as offsetof
+ values. */
+# define sa_alignof(type) (sizeof (type) <= 4 ? 4 : 8)
+#elif defined _AIX
+ /* Work around an AIX 3.2.5 xlc bug with enums constants defined as offsetof
+ values. */
+# define sa_alignof(type) (sizeof (type) <= 4 ? 4 : 8)
+#else
+# define sa_alignof(type) offsetof (struct { char __slot1; type __slot2; }, __slot2)
+#endif
+
+enum
+{
+/* The desired alignment of memory allocations is the maximum alignment
+ among all elementary types. */
+ sa_alignment_long = sa_alignof (long),
+ sa_alignment_double = sa_alignof (double),
+ sa_alignment_longlong = sa_alignof (long long),
+ sa_alignment_longdouble = sa_alignof (long double),
+ sa_alignment_max = ((sa_alignment_long - 1) | (sa_alignment_double - 1)
+ | (sa_alignment_longlong - 1)
+ | (sa_alignment_longdouble - 1)
+ ) + 1
+};
+
+#endif /* _MALLOCA_H */