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/* aligned memory allocation
Copyright 2022-2025 Free Software Foundation, Inc.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This file 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Paul Eggert. */
#ifndef ALIGNALLOC_H_
#define ALIGNALLOC_H_
/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE, _GL_ATTRIBUTE_ALLOC_SIZE,
_GL_ATTRIBUTE_MALLOC, _GL_ATTRIBUTE_RETURNS_NONNULL, HAVE_POSIX_MEMALIGN. */
#if !_GL_CONFIG_H_INCLUDED
#error "Please include config.h first."
#endif
#include <errno.h>
#include <stdlib.h>
#include "idx.h"
#if defined __CHERI_PURE_CAPABILITY__
# include <cheri.h>
#endif
_GL_INLINE_HEADER_BEGIN
#ifndef ALIGNALLOC_INLINE
# define ALIGNALLOC_INLINE _GL_INLINE
#endif
#ifdef __cplusplus
extern "C" {
#endif
/* Whether aligned_alloc supports any power-of-two alignment,
returns a nonnull pointer for size-zero allocations,
and sets errno on failure. */
#if 2 < __GLIBC__ + (16 <= __GLIBC_MINOR__)
# define ALIGNALLOC_VIA_ALIGNED_ALLOC 1
#else
# define ALIGNALLOC_VIA_ALIGNED_ALLOC 0
#endif
/* Work around AddressSanitizer bug.
https://gcc.gnu.org/PR104262
https://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20220124/1001910.html
*/
#ifdef __SANITIZE_ADDRESS__
# undef ALIGNALLOC_VIA_ALIGNED_ALLOC
# define ALIGNALLOC_VIA_ALIGNED_ALLOC 0
#endif
#ifdef __has_feature
# if __has_feature (address_sanitizer)
# undef ALIGNALLOC_VIA_ALIGNED_ALLOC
# define ALIGNALLOC_VIA_ALIGNED_ALLOC 0
# endif
#endif
#if ALIGNALLOC_VIA_ALIGNED_ALLOC || HAVE_POSIX_MEMALIGN
/* Free storage allocated via alignalloc. Do nothing if PTR is null. */
ALIGNALLOC_INLINE void
alignfree (void *ptr)
{
free (ptr);
}
/* Return an ALIGNMENT-aligned pointer to new storage of size SIZE,
or a null pointer (setting errno) if memory is exhausted.
ALIGNMENT must be a power of two.
If SIZE is zero, on success return a unique pointer each time.
To free storage later, call alignfree. */
ALIGNALLOC_INLINE
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2))
/* _GL_ATTRIBUTE_DEALLOC (alignfree, 1) */
void *
alignalloc (idx_t alignment, idx_t size)
{
if ((size_t) -1 < alignment)
alignment = (size_t) -1;
if ((size_t) -1 < size)
size = (size_t) -1;
# if ALIGNALLOC_VIA_ALIGNED_ALLOC
return aligned_alloc (alignment, size);
# else
void *ptr = NULL;
if (alignment < sizeof (void *))
alignment = sizeof (void *);
/* Work around posix_memalign glitch by treating a 0 size as if it were 1,
so that returning NULL is equivalent to failing. */
errno = posix_memalign (&ptr, alignment, size ? size : 1);
# if defined __CHERI_PURE_CAPABILITY__
if (ptr != NULL)
ptr = cheri_bounds_set (ptr, size);
# endif
return ptr;
# endif
}
#else /* ! (ALIGNALLOC_VIA_ALIGNED_ALLOC || HAVE_POSIX_MEMALIGN) */
void alignfree (void *);
void *alignalloc (idx_t, idx_t)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2))
_GL_ATTRIBUTE_DEALLOC (alignfree, 1);
#endif
/* Like alignalloc, but die instead of returning a null pointer. */
void *xalignalloc (idx_t, idx_t)
_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2))
_GL_ATTRIBUTE_RETURNS_NONNULL /* _GL_ATTRIBUTE_DEALLOC (alignfree, 1) */;
#ifdef __cplusplus
}
#endif
_GL_INLINE_HEADER_END
#endif /* !ALIGNALLOC_H_ */