1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2023 Google LLC. All rights reserved.
3 //
4 // Use of this source code is governed by a BSD-style
5 // license that can be found in the LICENSE file or at
6 // https://developers.google.com/open-source/licenses/bsd
7
8 #ifndef UPB_PORT_ATOMIC_H_
9 #define UPB_PORT_ATOMIC_H_
10
11 #include "upb/port/def.inc"
12
13 #ifdef UPB_USE_C11_ATOMICS
14
15 // IWYU pragma: begin_exports
16 #include <stdatomic.h>
17 #include <stdbool.h>
18 // IWYU pragma: end_exports
19
20 #define upb_Atomic_Init(addr, val) atomic_init(addr, val)
21 #define upb_Atomic_Load(addr, order) atomic_load_explicit(addr, order)
22 #define upb_Atomic_Store(addr, val, order) \
23 atomic_store_explicit(addr, val, order)
24 #define upb_Atomic_Add(addr, val, order) \
25 atomic_fetch_add_explicit(addr, val, order)
26 #define upb_Atomic_Sub(addr, val, order) \
27 atomic_fetch_sub_explicit(addr, val, order)
28 #define upb_Atomic_Exchange(addr, val, order) \
29 atomic_exchange_explicit(addr, val, order)
30 #define upb_Atomic_CompareExchangeStrong(addr, expected, desired, \
31 success_order, failure_order) \
32 atomic_compare_exchange_strong_explicit(addr, expected, desired, \
33 success_order, failure_order)
34 #define upb_Atomic_CompareExchangeWeak(addr, expected, desired, success_order, \
35 failure_order) \
36 atomic_compare_exchange_weak_explicit(addr, expected, desired, \
37 success_order, failure_order)
38
39 #else // !UPB_USE_C11_ATOMICS
40
41 #include <string.h>
42
43 #define upb_Atomic_Init(addr, val) (*addr = val)
44 #define upb_Atomic_Load(addr, order) (*addr)
45 #define upb_Atomic_Store(addr, val, order) (*(addr) = val)
46 #define upb_Atomic_Add(addr, val, order) (*(addr) += val)
47 #define upb_Atomic_Sub(addr, val, order) (*(addr) -= val)
48
_upb_NonAtomic_Exchange(void * addr,void * value)49 UPB_INLINE void* _upb_NonAtomic_Exchange(void* addr, void* value) {
50 void* old;
51 memcpy(&old, addr, sizeof(value));
52 memcpy(addr, &value, sizeof(value));
53 return old;
54 }
55
56 #define upb_Atomic_Exchange(addr, val, order) _upb_NonAtomic_Exchange(addr, val)
57
58 // `addr` and `expected` are logically double pointers.
_upb_NonAtomic_CompareExchangeStrongP(void * addr,void * expected,void * desired)59 UPB_INLINE bool _upb_NonAtomic_CompareExchangeStrongP(void* addr,
60 void* expected,
61 void* desired) {
62 if (memcmp(addr, expected, sizeof(desired)) == 0) {
63 memcpy(addr, &desired, sizeof(desired));
64 return true;
65 } else {
66 memcpy(expected, addr, sizeof(desired));
67 return false;
68 }
69 }
70
71 #define upb_Atomic_CompareExchangeStrong(addr, expected, desired, \
72 success_order, failure_order) \
73 _upb_NonAtomic_CompareExchangeStrongP((void*)addr, (void*)expected, \
74 (void*)desired)
75 #define upb_Atomic_CompareExchangeWeak(addr, expected, desired, success_order, \
76 failure_order) \
77 upb_Atomic_CompareExchangeStrong(addr, expected, desired, 0, 0)
78
79 #endif
80
81 #include "upb/port/undef.inc"
82
83 #endif // UPB_PORT_ATOMIC_H_
84