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/*
36** File:		prinrval.h
37** Description:	API to interval timing functions of NSPR.
38**
39**
40** NSPR provides interval times that are independent of network time
41** of day values. Interval times are (in theory) accurate regardless
42** of host processing requirements and also very cheap to acquire. It
43** is expected that getting an interval time while in a synchronized
44** function (holding one's lock).
45**/
46
47#if !defined(prinrval_h)
48#define prinrval_h
49
50#include "prtypes.h"
51
52PR_BEGIN_EXTERN_C
53
54/**********************************************************************/
55/************************* TYPES AND CONSTANTS ************************/
56/**********************************************************************/
57
58typedef PRUint32 PRIntervalTime;
59
60/***********************************************************************
61** DEFINES:     PR_INTERVAL_MIN
62**              PR_INTERVAL_MAX
63** DESCRIPTION:
64**  These two constants define the range (in ticks / second) of the
65**  platform dependent type, PRIntervalTime. These constants bound both
66**  the period and the resolution of a PRIntervalTime.
67***********************************************************************/
68#define PR_INTERVAL_MIN 1000UL
69#define PR_INTERVAL_MAX 100000UL
70
71/***********************************************************************
72** DEFINES:     PR_INTERVAL_NO_WAIT
73**              PR_INTERVAL_NO_TIMEOUT
74** DESCRIPTION:
75**  Two reserved constants are defined in the PRIntervalTime namespace.
76**  They are used to indicate that the process should wait no time (return
77**  immediately) or wait forever (never time out), respectively.
78***********************************************************************/
79#define PR_INTERVAL_NO_WAIT 0UL
80#define PR_INTERVAL_NO_TIMEOUT 0xffffffffUL
81
82/**********************************************************************/
83/****************************** FUNCTIONS *****************************/
84/**********************************************************************/
85
86/***********************************************************************
87** FUNCTION:    PR_IntervalNow
88** DESCRIPTION:
89**  Return the value of NSPR's free running interval timer. That timer
90**  can be used to establish epochs and determine intervals (be computing
91**  the difference between two times).
92** INPUTS:      void
93** OUTPUTS:     void
94** RETURN:      PRIntervalTime
95**
96** SIDE EFFECTS:
97**  None
98** RESTRICTIONS:
99**  The units of PRIntervalTime are platform dependent. They are chosen
100**  such that they are appropriate for the host OS, yet provide sufficient
101**  resolution and period to be useful to clients.
102** MEMORY:      N/A
103** ALGORITHM:   Platform dependent
104***********************************************************************/
105NSPR_API(PRIntervalTime) PR_IntervalNow(void);
106
107/***********************************************************************
108** FUNCTION:    PR_TicksPerSecond
109** DESCRIPTION:
110**  Return the number of ticks per second for PR_IntervalNow's clock.
111**  The value will be in the range [PR_INTERVAL_MIN..PR_INTERVAL_MAX].
112** INPUTS:      void
113** OUTPUTS:     void
114** RETURN:      PRUint32
115**
116** SIDE EFFECTS:
117**  None
118** RESTRICTIONS:
119**  None
120** MEMORY:      N/A
121** ALGORITHM:   N/A
122***********************************************************************/
123NSPR_API(PRUint32) PR_TicksPerSecond(void);
124
125/***********************************************************************
126** FUNCTION:    PR_SecondsToInterval
127**              PR_MillisecondsToInterval
128**              PR_MicrosecondsToInterval
129** DESCRIPTION:
130**  Convert standard clock units to platform dependent intervals.
131** INPUTS:      PRUint32
132** OUTPUTS:     void
133** RETURN:      PRIntervalTime
134**
135** SIDE EFFECTS:
136**  None
137** RESTRICTIONS:
138**  Conversion may cause overflow, which is not reported.
139** MEMORY:      N/A
140** ALGORITHM:   N/A
141***********************************************************************/
142NSPR_API(PRIntervalTime) PR_SecondsToInterval(PRUint32 seconds);
143NSPR_API(PRIntervalTime) PR_MillisecondsToInterval(PRUint32 milli);
144NSPR_API(PRIntervalTime) PR_MicrosecondsToInterval(PRUint32 micro);
145
146/***********************************************************************
147** FUNCTION:    PR_IntervalToSeconds
148**              PR_IntervalToMilliseconds
149**              PR_IntervalToMicroseconds
150** DESCRIPTION:
151**  Convert platform dependent intervals to standard clock units.
152** INPUTS:      PRIntervalTime
153** OUTPUTS:     void
154** RETURN:      PRUint32
155**
156** SIDE EFFECTS:
157**  None
158** RESTRICTIONS:
159**  Conversion may cause overflow, which is not reported.
160** MEMORY:      N/A
161** ALGORITHM:   N/A
162***********************************************************************/
163NSPR_API(PRUint32) PR_IntervalToSeconds(PRIntervalTime ticks);
164NSPR_API(PRUint32) PR_IntervalToMilliseconds(PRIntervalTime ticks);
165NSPR_API(PRUint32) PR_IntervalToMicroseconds(PRIntervalTime ticks);
166
167PR_END_EXTERN_C
168
169
170#endif /* !defined(prinrval_h) */
171
172/* prinrval.h */
173