nsprpub/pr/include/pratom.h@6474c204b198
nsprpub/pr/include/pratom.h
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 /* GLOBAL FUNCTIONS:
7 ** DESCRIPTION:
8 ** PR Atomic operations
9 */
11 #ifndef pratom_h___
12 #define pratom_h___
14 #include "prtypes.h"
15 #include "prlock.h"
17 PR_BEGIN_EXTERN_C
19 /*
20 ** FUNCTION: PR_AtomicIncrement
21 ** DESCRIPTION:
22 ** Atomically increment a 32 bit value.
23 ** INPUTS:
24 ** val: a pointer to the value to increment
25 ** RETURN:
26 ** the returned value is the result of the increment
27 */
28 NSPR_API(PRInt32) PR_AtomicIncrement(PRInt32 *val);
30 /*
31 ** FUNCTION: PR_AtomicDecrement
32 ** DESCRIPTION:
33 ** Atomically decrement a 32 bit value.
34 ** INPUTS:
35 ** val: a pointer to the value to decrement
36 ** RETURN:
37 ** the returned value is the result of the decrement
38 */
39 NSPR_API(PRInt32) PR_AtomicDecrement(PRInt32 *val);
41 /*
42 ** FUNCTION: PR_AtomicSet
43 ** DESCRIPTION:
44 ** Atomically set a 32 bit value.
45 ** INPUTS:
46 ** val: A pointer to a 32 bit value to be set
47 ** newval: The newvalue to assign to val
48 ** RETURN:
49 ** Returns the prior value
50 */
51 NSPR_API(PRInt32) PR_AtomicSet(PRInt32 *val, PRInt32 newval);
53 /*
54 ** FUNCTION: PR_AtomicAdd
55 ** DESCRIPTION:
56 ** Atomically add a 32 bit value.
57 ** INPUTS:
58 ** ptr: a pointer to the value to increment
59 ** val: value to be added
60 ** RETURN:
61 ** the returned value is the result of the addition
62 */
63 NSPR_API(PRInt32) PR_AtomicAdd(PRInt32 *ptr, PRInt32 val);
65 /*
66 ** MACRO: PR_ATOMIC_INCREMENT
67 ** MACRO: PR_ATOMIC_DECREMENT
68 ** MACRO: PR_ATOMIC_SET
69 ** MACRO: PR_ATOMIC_ADD
70 ** DESCRIPTION:
71 ** Macro versions of the atomic operations. They may be implemented
72 ** as compiler intrinsics.
73 **
74 ** IMPORTANT NOTE TO NSPR MAINTAINERS:
75 ** Implement these macros with compiler intrinsics only on platforms
76 ** where the PR_AtomicXXX functions are truly atomic (i.e., where the
77 ** configuration macro _PR_HAVE_ATOMIC_OPS is defined). Otherwise,
78 ** the macros and functions won't be compatible and can't be used
79 ** interchangeably.
80 */
81 #if defined(_WIN32) && !defined(_WIN32_WCE) && \
82 (!defined(_MSC_VER) || (_MSC_VER >= 1310))
84 long __cdecl _InterlockedIncrement(long volatile *Addend);
85 long __cdecl _InterlockedDecrement(long volatile *Addend);
86 long __cdecl _InterlockedExchange(long volatile *Target, long Value);
87 long __cdecl _InterlockedExchangeAdd(long volatile *Addend, long Value);
89 #ifdef _MSC_VER
90 #pragma intrinsic(_InterlockedIncrement)
91 #pragma intrinsic(_InterlockedDecrement)
92 #pragma intrinsic(_InterlockedExchange)
93 #pragma intrinsic(_InterlockedExchangeAdd)
94 #endif
96 #define PR_ATOMIC_INCREMENT(val) _InterlockedIncrement((long volatile *)(val))
97 #define PR_ATOMIC_DECREMENT(val) _InterlockedDecrement((long volatile *)(val))
98 #define PR_ATOMIC_SET(val, newval) \
99 _InterlockedExchange((long volatile *)(val), (long)(newval))
100 #define PR_ATOMIC_ADD(ptr, val) \
101 (_InterlockedExchangeAdd((long volatile *)(ptr), (long)(val)) + (val))
103 #elif ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) && \
104 ((defined(__APPLE__) && \
105 (defined(__ppc__) || defined(__i386__) || defined(__x86_64__))) || \
106 (defined(__linux__) && \
107 ((defined(__i386__) && \
108 defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || \
109 defined(__ia64__) || defined(__x86_64__) || \
110 defined(__powerpc__) || \
111 (defined(__arm__) && \
112 defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || \
113 defined(__aarch64__) || defined(__alpha))))
115 /*
116 * Because the GCC manual warns that some processors may support
117 * reduced functionality of __sync_lock_test_and_set, we test for the
118 * processors that we believe support a full atomic exchange operation.
119 */
121 #define PR_ATOMIC_INCREMENT(val) __sync_add_and_fetch(val, 1)
122 #define PR_ATOMIC_DECREMENT(val) __sync_sub_and_fetch(val, 1)
123 #define PR_ATOMIC_SET(val, newval) __sync_lock_test_and_set(val, newval)
124 #define PR_ATOMIC_ADD(ptr, val) __sync_add_and_fetch(ptr, val)
126 #else
128 #define PR_ATOMIC_INCREMENT(val) PR_AtomicIncrement(val)
129 #define PR_ATOMIC_DECREMENT(val) PR_AtomicDecrement(val)
130 #define PR_ATOMIC_SET(val, newval) PR_AtomicSet(val, newval)
131 #define PR_ATOMIC_ADD(ptr, val) PR_AtomicAdd(ptr, val)
133 #endif
135 /*
136 ** LIFO linked-list (stack)
137 */
138 typedef struct PRStackElemStr PRStackElem;
140 struct PRStackElemStr {
141 PRStackElem *prstk_elem_next; /* next pointer MUST be at offset 0;
142 assembly language code relies on this */
143 };
145 typedef struct PRStackStr PRStack;
147 /*
148 ** FUNCTION: PR_CreateStack
149 ** DESCRIPTION:
150 ** Create a stack, a LIFO linked list
151 ** INPUTS:
152 ** stack_name: a pointer to string containing the name of the stack
153 ** RETURN:
154 ** A pointer to the created stack, if successful, else NULL.
155 */
156 NSPR_API(PRStack *) PR_CreateStack(const char *stack_name);
158 /*
159 ** FUNCTION: PR_StackPush
160 ** DESCRIPTION:
161 ** Push an element on the top of the stack
162 ** INPUTS:
163 ** stack: pointer to the stack
164 ** stack_elem: pointer to the stack element
165 ** RETURN:
166 ** None
167 */
168 NSPR_API(void) PR_StackPush(PRStack *stack, PRStackElem *stack_elem);
170 /*
171 ** FUNCTION: PR_StackPop
172 ** DESCRIPTION:
173 ** Remove the element on the top of the stack
174 ** INPUTS:
175 ** stack: pointer to the stack
176 ** RETURN:
177 ** A pointer to the stack element removed from the top of the stack,
178 ** if non-empty,
179 ** else NULL
180 */
181 NSPR_API(PRStackElem *) PR_StackPop(PRStack *stack);
183 /*
184 ** FUNCTION: PR_DestroyStack
185 ** DESCRIPTION:
186 ** Destroy the stack
187 ** INPUTS:
188 ** stack: pointer to the stack
189 ** RETURN:
190 ** PR_SUCCESS - if successfully deleted
191 ** PR_FAILURE - if the stack is not empty
192 ** PR_GetError will return
193 ** PR_INVALID_STATE_ERROR - stack is not empty
194 */
195 NSPR_API(PRStatus) PR_DestroyStack(PRStack *stack);
197 PR_END_EXTERN_C
199 #endif /* pratom_h___ */
