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/* Helper macros for pointer arithmetic.
Copyright (C) 2012-2024 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 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.
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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _LIBC_POINTER_ARITH_H
#define _LIBC_POINTER_ARITH_H 1
#include <stdint.h>
/* 1 if 'type' is a pointer type, 0 otherwise. */
# define __pointer_type(type) (__builtin_classify_type ((type) 0) == 5)
/* intptr_t if P is true, or T if P is false. */
# define __integer_if_pointer_type_sub(T, P) \
__typeof__ (*(0 ? (__typeof__ (0 ? (T *) 0 : (void *) (P))) 0 \
: (__typeof__ (0 ? (intptr_t *) 0 : (void *) (!(P)))) 0))
/* intptr_t if EXPR has a pointer type, or the type of EXPR otherwise. */
# define __integer_if_pointer_type(expr) \
__integer_if_pointer_type_sub(__typeof__ ((__typeof__ (expr)) 0), \
__pointer_type (__typeof__ (expr)))
/* Cast an integer or a pointer VAL to integer with proper type. */
# define cast_to_integer(val) ((__integer_if_pointer_type (val)) (val))
/* Cast an integer VAL to void * pointer. */
# define cast_to_pointer(val) ((void *) (uintptr_t) (val))
/* Align a value by rounding down to closest size.
e.g. Using size of 4096, we get this behavior:
{4095, 4096, 4097} = {0, 4096, 4096}. */
#define ALIGN_DOWN(base, size) ((base) & -((__typeof__ (base)) (size)))
/* Align a value by rounding up to closest size.
e.g. Using size of 4096, we get this behavior:
{4095, 4096, 4097} = {4096, 4096, 8192}.
Note: The size argument has side effects (expanded multiple times). */
#define ALIGN_UP(base, size) ALIGN_DOWN ((base) + (size) - 1, (size))
/* Same as ALIGN_DOWN(), but automatically casts when base is a pointer. */
#define PTR_ALIGN_DOWN(base, size) \
((__typeof__ (base)) ALIGN_DOWN ((uintptr_t) (base), (size)))
/* Same as ALIGN_UP(), but automatically casts when base is a pointer. */
#define PTR_ALIGN_UP(base, size) \
((__typeof__ (base)) ALIGN_UP ((uintptr_t) (base), (size)))
/* Check if BASE is aligned on SIZE */
#define PTR_IS_ALIGNED(base, size) \
((((uintptr_t) (base)) & (size - 1)) == 0)
/* Returns the ptrdiff_t difference between P1 and P2. */
#define PTR_DIFF(p1, p2) \
((ptrdiff_t)((uintptr_t)(p1) - (uintptr_t)(p2)))
#endif
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