1*1b191cb5SApple OSS Distributions /* 2*1b191cb5SApple OSS Distributions * Copyright (c) 2021 Apple Inc. All rights reserved. 3*1b191cb5SApple OSS Distributions * 4*1b191cb5SApple OSS Distributions * @APPLE_LICENSE_HEADER_START@ 5*1b191cb5SApple OSS Distributions * 6*1b191cb5SApple OSS Distributions * This file contains Original Code and/or Modifications of Original Code 7*1b191cb5SApple OSS Distributions * as defined in and that are subject to the Apple Public Source License 8*1b191cb5SApple OSS Distributions * Version 2.0 (the 'License'). You may not use this file except in 9*1b191cb5SApple OSS Distributions * compliance with the License. Please obtain a copy of the License at 10*1b191cb5SApple OSS Distributions * http://www.opensource.apple.com/apsl/ and read it before using this 11*1b191cb5SApple OSS Distributions * file. 12*1b191cb5SApple OSS Distributions * 13*1b191cb5SApple OSS Distributions * The Original Code and all software distributed under the License are 14*1b191cb5SApple OSS Distributions * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 15*1b191cb5SApple OSS Distributions * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 16*1b191cb5SApple OSS Distributions * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 17*1b191cb5SApple OSS Distributions * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 18*1b191cb5SApple OSS Distributions * Please see the License for the specific language governing rights and 19*1b191cb5SApple OSS Distributions * limitations under the License. 20*1b191cb5SApple OSS Distributions * 21*1b191cb5SApple OSS Distributions * @APPLE_LICENSE_HEADER_END@ 22*1b191cb5SApple OSS Distributions */ 23*1b191cb5SApple OSS Distributions 24*1b191cb5SApple OSS Distributions #ifndef _OS_ALLOC_UTIL_H 25*1b191cb5SApple OSS Distributions #define _OS_ALLOC_UTIL_H 26*1b191cb5SApple OSS Distributions 27*1b191cb5SApple OSS Distributions #include <sys/cdefs.h> 28*1b191cb5SApple OSS Distributions #if defined(__cplusplus) && __cplusplus >= 201103L 29*1b191cb5SApple OSS Distributions extern "C++" { 30*1b191cb5SApple OSS Distributions #include <os/cpp_util.h> 31*1b191cb5SApple OSS Distributions } 32*1b191cb5SApple OSS Distributions #endif 33*1b191cb5SApple OSS Distributions 34*1b191cb5SApple OSS Distributions /*! 35*1b191cb5SApple OSS Distributions * @macro os_is_ptr_like 36*1b191cb5SApple OSS Distributions * 37*1b191cb5SApple OSS Distributions * @abstract 38*1b191cb5SApple OSS Distributions * Tell whether the given expression resembles a pointer. 39*1b191cb5SApple OSS Distributions * 40*1b191cb5SApple OSS Distributions * @discussion 41*1b191cb5SApple OSS Distributions * When pointer bounds are enabled, only types that are actually classified 42*1b191cb5SApple OSS Distributions * as pointers will be considered pointer-like. Otherwise, any pointer-sized 43*1b191cb5SApple OSS Distributions * type will be considered pointer-like. 44*1b191cb5SApple OSS Distributions * 45*1b191cb5SApple OSS Distributions * @param P the expression to be checked 46*1b191cb5SApple OSS Distributions */ 47*1b191cb5SApple OSS Distributions #if __has_ptrcheck 48*1b191cb5SApple OSS Distributions #define os_is_ptr_like(P) (__builtin_classify_type(P) == 5) 49*1b191cb5SApple OSS Distributions #else /* __has_ptrcheck */ 50*1b191cb5SApple OSS Distributions #define os_is_ptr_like(P) (sizeof(P) == sizeof(void *)) 51*1b191cb5SApple OSS Distributions #endif /* __has_ptrcheck */ 52*1b191cb5SApple OSS Distributions 53*1b191cb5SApple OSS Distributions /*! 54*1b191cb5SApple OSS Distributions * @macro os_ptr_load_and_erase 55*1b191cb5SApple OSS Distributions * 56*1b191cb5SApple OSS Distributions * @abstract 57*1b191cb5SApple OSS Distributions * Load the value of @c elem into a temporary, set @c elem to NULL, and 58*1b191cb5SApple OSS Distributions * return the value. 59*1b191cb5SApple OSS Distributions * 60*1b191cb5SApple OSS Distributions * @param elem the pointer whose value will be taken, and which will 61*1b191cb5SApple OSS Distributions * be set to NULL. 62*1b191cb5SApple OSS Distributions */ 63*1b191cb5SApple OSS Distributions #define os_ptr_load_and_erase(elem) ({ \ 64*1b191cb5SApple OSS Distributions _Static_assert(os_is_ptr_like(elem), \ 65*1b191cb5SApple OSS Distributions "elem isn't pointer sized"); \ 66*1b191cb5SApple OSS Distributions __auto_type *__single __eptr = &(elem); \ 67*1b191cb5SApple OSS Distributions __auto_type __elem = *__eptr; \ 68*1b191cb5SApple OSS Distributions _Pragma("clang diagnostic push") \ 69*1b191cb5SApple OSS Distributions _Pragma("clang diagnostic ignored \"-Wold-style-cast\"") \ 70*1b191cb5SApple OSS Distributions *__eptr = (__typeof__(__elem))NULL; \ 71*1b191cb5SApple OSS Distributions _Pragma("clang diagnostic pop") \ 72*1b191cb5SApple OSS Distributions __elem; \ 73*1b191cb5SApple OSS Distributions }) 74*1b191cb5SApple OSS Distributions 75*1b191cb5SApple OSS Distributions #endif /* _OS_ALLOC_UTIL_H */ 76