source: vbox/trunk/src/libs/xpcom18a4/nsprpub/pr/include/pratom.h@ 4634

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 * for the specific language governing rights and limitations under the
 * License.
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 * The Original Code is the Netscape Portable Runtime (NSPR).
 *
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 *
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/* 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);

/*
** 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___ */