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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* GLOBAL FUNCTIONS:
** DESCRIPTION:
** PR Atomic operations
*/
#ifndef pratom_h___
#define pratom_h___
#include "prtypes.h"
#include "prlock.h"
PR_BEGIN_EXTERN_C
/*
** FUNCTION: PR_AtomicIncrement
** DESCRIPTION:
** Atomically increment a 32 bit value.
** INPUTS:
** val: a pointer to the value to increment
** RETURN:
** the returned value is the result of the increment
*/
NSPR_API(PRInt32) PR_AtomicIncrement(PRInt32 *val);
/*
** FUNCTION: PR_AtomicDecrement
** DESCRIPTION:
** Atomically decrement a 32 bit value.
** INPUTS:
** val: a pointer to the value to decrement
** RETURN:
** the returned value is the result of the decrement
*/
NSPR_API(PRInt32) PR_AtomicDecrement(PRInt32 *val);
/*
** FUNCTION: PR_AtomicSet
** DESCRIPTION:
** Atomically set a 32 bit value.
** INPUTS:
** val: A pointer to a 32 bit value to be set
** newval: The newvalue to assign to val
** RETURN:
** Returns the prior value
*/
NSPR_API(PRInt32) PR_AtomicSet(PRInt32 *val, PRInt32 newval);
/*
** FUNCTION: PR_AtomicAdd
** DESCRIPTION:
** Atomically add a 32 bit value.
** INPUTS:
** ptr: a pointer to the value to increment
** val: value to be added
** RETURN:
** the returned value is the result of the addition
*/
NSPR_API(PRInt32) PR_AtomicAdd(PRInt32 *ptr, PRInt32 val);
/*
** MACRO: PR_ATOMIC_INCREMENT
** MACRO: PR_ATOMIC_DECREMENT
** MACRO: PR_ATOMIC_SET
** MACRO: PR_ATOMIC_ADD
** DESCRIPTION:
** Macro versions of the atomic operations. They may be implemented
** as compiler intrinsics.
**
** IMPORTANT NOTE TO NSPR MAINTAINERS:
** Implement these macros with compiler intrinsics only on platforms
** where the PR_AtomicXXX functions are truly atomic (i.e., where the
** configuration macro _PR_HAVE_ATOMIC_OPS is defined). Otherwise,
** the macros and functions won't be compatible and can't be used
** interchangeably.
*/
#if defined(_WIN32) && !defined(_WIN32_WCE) && \
(!defined(_MSC_VER) || (_MSC_VER >= 1310))
#include <intrin.h>
#ifdef _MSC_VER
#pragma intrinsic(_InterlockedIncrement)
#pragma intrinsic(_InterlockedDecrement)
#pragma intrinsic(_InterlockedExchange)
#pragma intrinsic(_InterlockedExchangeAdd)
#endif
#define PR_ATOMIC_INCREMENT(val) _InterlockedIncrement((long volatile *)(val))
#define PR_ATOMIC_DECREMENT(val) _InterlockedDecrement((long volatile *)(val))
#define PR_ATOMIC_SET(val, newval) \
_InterlockedExchange((long volatile *)(val), (long)(newval))
#define PR_ATOMIC_ADD(ptr, val) \
(_InterlockedExchangeAdd((long volatile *)(ptr), (long)(val)) + (val))
#elif ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) && \
((defined(__APPLE__) && \
(defined(__ppc__) || defined(__i386__) || defined(__x86_64__))) || \
(defined(__linux__) && \
((defined(__i386__) && \
defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || \
defined(__ia64__) || defined(__x86_64__) || \
defined(__powerpc__) || \
(defined(__arm__) && \
defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || \
defined(__aarch64__) || defined(__alpha) || \
(defined(__mips__) && \
defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)))))
/*
* Because the GCC manual warns that some processors may support
* reduced functionality of __sync_lock_test_and_set, we test for the
* processors that we believe support a full atomic exchange operation.
*/
#define PR_ATOMIC_INCREMENT(val) __sync_add_and_fetch(val, 1)
#define PR_ATOMIC_DECREMENT(val) __sync_sub_and_fetch(val, 1)
#define PR_ATOMIC_SET(val, newval) __sync_lock_test_and_set(val, newval)
#define PR_ATOMIC_ADD(ptr, val) __sync_add_and_fetch(ptr, val)
#else
#define PR_ATOMIC_INCREMENT(val) PR_AtomicIncrement(val)
#define PR_ATOMIC_DECREMENT(val) PR_AtomicDecrement(val)
#define PR_ATOMIC_SET(val, newval) PR_AtomicSet(val, newval)
#define PR_ATOMIC_ADD(ptr, val) PR_AtomicAdd(ptr, val)
#endif
/*
** LIFO linked-list (stack)
*/
typedef struct PRStackElemStr PRStackElem;
struct PRStackElemStr {
PRStackElem *prstk_elem_next; /* next pointer MUST be at offset 0;
assembly language code relies on this */
};
typedef struct PRStackStr PRStack;
/*
** FUNCTION: PR_CreateStack
** DESCRIPTION:
** Create a stack, a LIFO linked list
** INPUTS:
** stack_name: a pointer to string containing the name of the stack
** RETURN:
** A pointer to the created stack, if successful, else NULL.
*/
NSPR_API(PRStack *) PR_CreateStack(const char *stack_name);
/*
** FUNCTION: PR_StackPush
** DESCRIPTION:
** Push an element on the top of the stack
** INPUTS:
** stack: pointer to the stack
** stack_elem: pointer to the stack element
** RETURN:
** None
*/
NSPR_API(void) PR_StackPush(PRStack *stack, PRStackElem *stack_elem);
/*
** FUNCTION: PR_StackPop
** DESCRIPTION:
** Remove the element on the top of the stack
** INPUTS:
** stack: pointer to the stack
** RETURN:
** A pointer to the stack element removed from the top of the stack,
** if non-empty,
** else NULL
*/
NSPR_API(PRStackElem *) PR_StackPop(PRStack *stack);
/*
** FUNCTION: PR_DestroyStack
** DESCRIPTION:
** Destroy the stack
** INPUTS:
** stack: pointer to the stack
** RETURN:
** PR_SUCCESS - if successfully deleted
** PR_FAILURE - if the stack is not empty
** PR_GetError will return
** PR_INVALID_STATE_ERROR - stack is not empty
*/
NSPR_API(PRStatus) PR_DestroyStack(PRStack *stack);
PR_END_EXTERN_C
#endif /* pratom_h___ */
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