1*fdd8201dSApple OSS Distributions /* 2*fdd8201dSApple OSS Distributions * Copyright (c) 2021 Apple Inc. All rights reserved. 3*fdd8201dSApple OSS Distributions * 4*fdd8201dSApple OSS Distributions * @APPLE_LICENSE_HEADER_START@ 5*fdd8201dSApple OSS Distributions * 6*fdd8201dSApple OSS Distributions * This file contains Original Code and/or Modifications of Original Code 7*fdd8201dSApple OSS Distributions * as defined in and that are subject to the Apple Public Source License 8*fdd8201dSApple OSS Distributions * Version 2.0 (the 'License'). You may not use this file except in 9*fdd8201dSApple OSS Distributions * compliance with the License. Please obtain a copy of the License at 10*fdd8201dSApple OSS Distributions * http://www.opensource.apple.com/apsl/ and read it before using this 11*fdd8201dSApple OSS Distributions * file. 12*fdd8201dSApple OSS Distributions * 13*fdd8201dSApple OSS Distributions * The Original Code and all software distributed under the License are 14*fdd8201dSApple OSS Distributions * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 15*fdd8201dSApple OSS Distributions * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 16*fdd8201dSApple OSS Distributions * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 17*fdd8201dSApple OSS Distributions * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 18*fdd8201dSApple OSS Distributions * Please see the License for the specific language governing rights and 19*fdd8201dSApple OSS Distributions * limitations under the License. 20*fdd8201dSApple OSS Distributions * 21*fdd8201dSApple OSS Distributions * @APPLE_LICENSE_HEADER_END@ 22*fdd8201dSApple OSS Distributions */ 23*fdd8201dSApple OSS Distributions 24*fdd8201dSApple OSS Distributions #ifndef _OS_ALLOC_UTIL_H 25*fdd8201dSApple OSS Distributions #define _OS_ALLOC_UTIL_H 26*fdd8201dSApple OSS Distributions 27*fdd8201dSApple OSS Distributions #include <sys/cdefs.h> 28*fdd8201dSApple OSS Distributions #if defined(__cplusplus) && __cplusplus >= 201103L 29*fdd8201dSApple OSS Distributions extern "C++" { 30*fdd8201dSApple OSS Distributions #include <os/cpp_util.h> 31*fdd8201dSApple OSS Distributions } 32*fdd8201dSApple OSS Distributions #endif 33*fdd8201dSApple OSS Distributions 34*fdd8201dSApple OSS Distributions /*! 35*fdd8201dSApple OSS Distributions * @macro os_is_ptr_like 36*fdd8201dSApple OSS Distributions * 37*fdd8201dSApple OSS Distributions * @abstract 38*fdd8201dSApple OSS Distributions * Tell whether the given expression resembles a pointer. 39*fdd8201dSApple OSS Distributions * 40*fdd8201dSApple OSS Distributions * @discussion 41*fdd8201dSApple OSS Distributions * When pointer bounds are enabled, only types that are actually classified 42*fdd8201dSApple OSS Distributions * as pointers will be considered pointer-like. Otherwise, any pointer-sized 43*fdd8201dSApple OSS Distributions * type will be considered pointer-like. 44*fdd8201dSApple OSS Distributions * 45*fdd8201dSApple OSS Distributions * @param P the expression to be checked 46*fdd8201dSApple OSS Distributions */ 47*fdd8201dSApple OSS Distributions #if __has_ptrcheck 48*fdd8201dSApple OSS Distributions #define os_is_ptr_like(P) (__builtin_classify_type(P) == 5) 49*fdd8201dSApple OSS Distributions #else /* __has_ptrcheck */ 50*fdd8201dSApple OSS Distributions #define os_is_ptr_like(P) (sizeof(P) == sizeof(void *)) 51*fdd8201dSApple OSS Distributions #endif /* __has_ptrcheck */ 52*fdd8201dSApple OSS Distributions 53*fdd8201dSApple OSS Distributions /*! 54*fdd8201dSApple OSS Distributions * @macro os_ptr_load_and_erase 55*fdd8201dSApple OSS Distributions * 56*fdd8201dSApple OSS Distributions * @abstract 57*fdd8201dSApple OSS Distributions * Load the value of @c elem into a temporary, set @c elem to NULL, and 58*fdd8201dSApple OSS Distributions * return the value. 59*fdd8201dSApple OSS Distributions * 60*fdd8201dSApple OSS Distributions * @param elem the pointer whose value will be taken, and which will 61*fdd8201dSApple OSS Distributions * be set to NULL. 62*fdd8201dSApple OSS Distributions */ 63*fdd8201dSApple OSS Distributions #define os_ptr_load_and_erase(elem) ({ \ 64*fdd8201dSApple OSS Distributions _Static_assert(os_is_ptr_like(elem), \ 65*fdd8201dSApple OSS Distributions "elem isn't pointer sized"); \ 66*fdd8201dSApple OSS Distributions __auto_type __eptr = &(elem); \ 67*fdd8201dSApple OSS Distributions __auto_type __elem = *__eptr; \ 68*fdd8201dSApple OSS Distributions _Pragma("clang diagnostic push") \ 69*fdd8201dSApple OSS Distributions _Pragma("clang diagnostic ignored \"-Wold-style-cast\"") \ 70*fdd8201dSApple OSS Distributions *__eptr = (__typeof__(__elem))NULL; \ 71*fdd8201dSApple OSS Distributions _Pragma("clang diagnostic pop") \ 72*fdd8201dSApple OSS Distributions __elem; \ 73*fdd8201dSApple OSS Distributions }) 74*fdd8201dSApple OSS Distributions 75*fdd8201dSApple OSS Distributions #endif /* _OS_ALLOC_UTIL_H */ 76