1*c54f35caSApple OSS Distributions /* 2*c54f35caSApple OSS Distributions * Copyright (c) 2021 Apple Inc. All rights reserved. 3*c54f35caSApple OSS Distributions * 4*c54f35caSApple OSS Distributions * @APPLE_LICENSE_HEADER_START@ 5*c54f35caSApple OSS Distributions * 6*c54f35caSApple OSS Distributions * This file contains Original Code and/or Modifications of Original Code 7*c54f35caSApple OSS Distributions * as defined in and that are subject to the Apple Public Source License 8*c54f35caSApple OSS Distributions * Version 2.0 (the 'License'). You may not use this file except in 9*c54f35caSApple OSS Distributions * compliance with the License. Please obtain a copy of the License at 10*c54f35caSApple OSS Distributions * http://www.opensource.apple.com/apsl/ and read it before using this 11*c54f35caSApple OSS Distributions * file. 12*c54f35caSApple OSS Distributions * 13*c54f35caSApple OSS Distributions * The Original Code and all software distributed under the License are 14*c54f35caSApple OSS Distributions * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 15*c54f35caSApple OSS Distributions * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 16*c54f35caSApple OSS Distributions * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 17*c54f35caSApple OSS Distributions * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 18*c54f35caSApple OSS Distributions * Please see the License for the specific language governing rights and 19*c54f35caSApple OSS Distributions * limitations under the License. 20*c54f35caSApple OSS Distributions * 21*c54f35caSApple OSS Distributions * @APPLE_LICENSE_HEADER_END@ 22*c54f35caSApple OSS Distributions */ 23*c54f35caSApple OSS Distributions 24*c54f35caSApple OSS Distributions #ifndef _OS_ALLOC_UTIL_H 25*c54f35caSApple OSS Distributions #define _OS_ALLOC_UTIL_H 26*c54f35caSApple OSS Distributions 27*c54f35caSApple OSS Distributions #include <sys/cdefs.h> 28*c54f35caSApple OSS Distributions #if defined(__cplusplus) && __cplusplus >= 201103L 29*c54f35caSApple OSS Distributions extern "C++" { 30*c54f35caSApple OSS Distributions #include <os/cpp_util.h> 31*c54f35caSApple OSS Distributions } 32*c54f35caSApple OSS Distributions #endif 33*c54f35caSApple OSS Distributions 34*c54f35caSApple OSS Distributions /*! 35*c54f35caSApple OSS Distributions * @macro os_is_ptr_like 36*c54f35caSApple OSS Distributions * 37*c54f35caSApple OSS Distributions * @abstract 38*c54f35caSApple OSS Distributions * Tell whether the given expression resembles a pointer. 39*c54f35caSApple OSS Distributions * 40*c54f35caSApple OSS Distributions * @discussion 41*c54f35caSApple OSS Distributions * When pointer bounds are enabled, only types that are actually classified 42*c54f35caSApple OSS Distributions * as pointers will be considered pointer-like. Otherwise, any pointer-sized 43*c54f35caSApple OSS Distributions * type will be considered pointer-like. 44*c54f35caSApple OSS Distributions * 45*c54f35caSApple OSS Distributions * @param P the expression to be checked 46*c54f35caSApple OSS Distributions */ 47*c54f35caSApple OSS Distributions #if __has_ptrcheck 48*c54f35caSApple OSS Distributions #define os_is_ptr_like(P) (__builtin_classify_type(P) == 5) 49*c54f35caSApple OSS Distributions #else /* __has_ptrcheck */ 50*c54f35caSApple OSS Distributions #define os_is_ptr_like(P) (sizeof(P) == sizeof(void *)) 51*c54f35caSApple OSS Distributions #endif /* __has_ptrcheck */ 52*c54f35caSApple OSS Distributions 53*c54f35caSApple OSS Distributions /*! 54*c54f35caSApple OSS Distributions * @macro os_ptr_load_and_erase 55*c54f35caSApple OSS Distributions * 56*c54f35caSApple OSS Distributions * @abstract 57*c54f35caSApple OSS Distributions * Load the value of @c elem into a temporary, set @c elem to NULL, and 58*c54f35caSApple OSS Distributions * return the value. 59*c54f35caSApple OSS Distributions * 60*c54f35caSApple OSS Distributions * @param elem the pointer whose value will be taken, and which will 61*c54f35caSApple OSS Distributions * be set to NULL. 62*c54f35caSApple OSS Distributions */ 63*c54f35caSApple OSS Distributions #define os_ptr_load_and_erase(elem) ({ \ 64*c54f35caSApple OSS Distributions _Static_assert(os_is_ptr_like(elem), \ 65*c54f35caSApple OSS Distributions "elem isn't pointer sized"); \ 66*c54f35caSApple OSS Distributions __auto_type *__single __eptr = &(elem); \ 67*c54f35caSApple OSS Distributions __auto_type __elem = *__eptr; \ 68*c54f35caSApple OSS Distributions _Pragma("clang diagnostic push") \ 69*c54f35caSApple OSS Distributions _Pragma("clang diagnostic ignored \"-Wold-style-cast\"") \ 70*c54f35caSApple OSS Distributions *__eptr = (__typeof__(__elem))NULL; \ 71*c54f35caSApple OSS Distributions _Pragma("clang diagnostic pop") \ 72*c54f35caSApple OSS Distributions __elem; \ 73*c54f35caSApple OSS Distributions }) 74*c54f35caSApple OSS Distributions 75*c54f35caSApple OSS Distributions #endif /* _OS_ALLOC_UTIL_H */ 76