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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___ */