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      1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /*
      3  * The contents of this file are subject to the Mozilla Public
      4  * License Version 1.1 (the "License"); you may not use this file
      5  * except in compliance with the License. You may obtain a copy of
      6  * the License at http://www.mozilla.org/MPL/
      7  *
      8  * Software distributed under the License is distributed on an "AS
      9  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
     10  * implied. See the License for the specific language governing
     11  * rights and limitations under the License.
     12  *
     13  * The Original Code is the Netscape Portable Runtime (NSPR).
     14  *
     15  * The Initial Developer of the Original Code is Netscape
     16  * Communications Corporation.  Portions created by Netscape are
     17  * Copyright (C) 1998-2000 Netscape Communications Corporation.  All
     18  * Rights Reserved.
     19  *
     20  * Contributor(s):
     21  *
     22  * Alternatively, the contents of this file may be used under the
     23  * terms of the GNU General Public License Version 2 or later (the
     24  * "GPL"), in which case the provisions of the GPL are applicable
     25  * instead of those above.  If you wish to allow use of your
     26  * version of this file only under the terms of the GPL and not to
     27  * allow others to use your version of this file under the MPL,
     28  * indicate your decision by deleting the provisions above and
     29  * replace them with the notice and other provisions required by
     30  * the GPL.  If you do not delete the provisions above, a recipient
     31  * may use your version of this file under either the MPL or the
     32  * GPL.
     33  */
     34 
     35 /* GLOBAL FUNCTIONS:
     36 ** DESCRIPTION:
     37 **     PR Atomic operations
     38 */
     39 
     40 #ifndef pratom_h___
     41 #define pratom_h___
     42 
     43 #include "prtypes.h"
     44 #include "prlock.h"
     45 
     46 PR_BEGIN_EXTERN_C
     47 
     48 /*
     49 ** FUNCTION: PR_AtomicIncrement
     50 ** DESCRIPTION:
     51 **    Atomically increment a 32 bit value.
     52 ** INPUTS:
     53 **    val:  a pointer to the value to increment
     54 ** RETURN:
     55 **    the returned value is the result of the increment
     56 */
     57 NSPR_API(PRInt32)	PR_AtomicIncrement(PRInt32 *val);
     58 
     59 /*
     60 ** FUNCTION: PR_AtomicDecrement
     61 ** DESCRIPTION:
     62 **    Atomically decrement a 32 bit value.
     63 ** INPUTS:
     64 **    val:  a pointer to the value to decrement
     65 ** RETURN:
     66 **    the returned value is the result of the decrement
     67 */
     68 NSPR_API(PRInt32)	PR_AtomicDecrement(PRInt32 *val);
     69 
     70 /*
     71 ** FUNCTION: PR_AtomicSet
     72 ** DESCRIPTION:
     73 **    Atomically set a 32 bit value.
     74 ** INPUTS:
     75 **    val: A pointer to a 32 bit value to be set
     76 **    newval: The newvalue to assign to val
     77 ** RETURN:
     78 **    Returns the prior value
     79 */
     80 NSPR_API(PRInt32) PR_AtomicSet(PRInt32 *val, PRInt32 newval);
     81 
     82 /*
     83 ** FUNCTION: PR_AtomicAdd
     84 ** DESCRIPTION:
     85 **    Atomically add a 32 bit value.
     86 ** INPUTS:
     87 **    ptr:  a pointer to the value to increment
     88 **	  val:  value to be added
     89 ** RETURN:
     90 **    the returned value is the result of the addition
     91 */
     92 NSPR_API(PRInt32)	PR_AtomicAdd(PRInt32 *ptr, PRInt32 val);
     93 
     94 /*
     95 ** LIFO linked-list (stack)
     96 */
     97 typedef struct PRStackElemStr PRStackElem;
     98 
     99 struct PRStackElemStr {
    100     PRStackElem	*prstk_elem_next;	/* next pointer MUST be at offset 0;
    101 									  assembly language code relies on this */
    102 };
    103 
    104 typedef struct PRStackStr PRStack;
    105 
    106 /*
    107 ** FUNCTION: PR_CreateStack
    108 ** DESCRIPTION:
    109 **    Create a stack, a LIFO linked list
    110 ** INPUTS:
    111 **    stack_name:  a pointer to string containing the name of the stack
    112 ** RETURN:
    113 **    A pointer to the created stack, if successful, else NULL.
    114 */
    115 NSPR_API(PRStack *)	PR_CreateStack(const char *stack_name);
    116 
    117 /*
    118 ** FUNCTION: PR_StackPush
    119 ** DESCRIPTION:
    120 **    Push an element on the top of the stack
    121 ** INPUTS:
    122 **    stack:		pointer to the stack
    123 **    stack_elem:	pointer to the stack element
    124 ** RETURN:
    125 **    None
    126 */
    127 NSPR_API(void)			PR_StackPush(PRStack *stack, PRStackElem *stack_elem);
    128 
    129 /*
    130 ** FUNCTION: PR_StackPop
    131 ** DESCRIPTION:
    132 **    Remove the element on the top of the stack
    133 ** INPUTS:
    134 **    stack:		pointer to the stack
    135 ** RETURN:
    136 **    A pointer to the stack element removed from the top of the stack,
    137 **	  if non-empty,
    138 **    else NULL
    139 */
    140 NSPR_API(PRStackElem *)	PR_StackPop(PRStack *stack);
    141 
    142 /*
    143 ** FUNCTION: PR_DestroyStack
    144 ** DESCRIPTION:
    145 **    Destroy the stack
    146 ** INPUTS:
    147 **    stack:		pointer to the stack
    148 ** RETURN:
    149 **    PR_SUCCESS - if successfully deleted
    150 **	  PR_FAILURE - if the stack is not empty
    151 **					PR_GetError will return
    152 **						PR_INVALID_STATE_ERROR - stack is not empty
    153 */
    154 NSPR_API(PRStatus)		PR_DestroyStack(PRStack *stack);
    155 
    156 PR_END_EXTERN_C
    157 
    158 #endif /* pratom_h___ */
    159