/* Helper macros for pointer arithmetic. Copyright (C) 2012-2018 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 <http://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)) /* 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))) #endif