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 *----------------------------------------------------------------------
37 *
38 * prtime.h --
39 *
40 *     NSPR date and time functions
41 *
42 *-----------------------------------------------------------------------
43 */
44
45#ifndef prtime_h___
46#define prtime_h___
47
48#include "prlong.h"
49
50PR_BEGIN_EXTERN_C
51
52/**********************************************************************/
53/************************* TYPES AND CONSTANTS ************************/
54/**********************************************************************/
55
56#define PR_MSEC_PER_SEC		1000UL
57#define PR_USEC_PER_SEC		1000000UL
58#define PR_NSEC_PER_SEC		1000000000UL
59#define PR_USEC_PER_MSEC	1000UL
60#define PR_NSEC_PER_MSEC	1000000UL
61
62/*
63 * PRTime --
64 *
65 *     NSPR represents basic time as 64-bit signed integers relative
66 *     to midnight (00:00:00), January 1, 1970 Greenwich Mean Time (GMT).
67 *     (GMT is also known as Coordinated Universal Time, UTC.)
68 *     The units of time are in microseconds. Negative times are allowed
69 *     to represent times prior to the January 1970 epoch. Such values are
70 *     intended to be exported to other systems or converted to human
71 *     readable form.
72 *
73 *     Notes on porting: PRTime corresponds to time_t in ANSI C.  NSPR 1.0
74 *     simply uses PRInt64.
75 */
76
77typedef PRInt64 PRTime;
78
79/*
80 * Time zone and daylight saving time corrections applied to GMT to
81 * obtain the local time of some geographic location
82 */
83
84typedef struct PRTimeParameters {
85    PRInt32 tp_gmt_offset;     /* the offset from GMT in seconds */
86    PRInt32 tp_dst_offset;     /* contribution of DST in seconds */
87} PRTimeParameters;
88
89/*
90 * PRExplodedTime --
91 *
92 *     Time broken down into human-readable components such as year, month,
93 *     day, hour, minute, second, and microsecond.  Time zone and daylight
94 *     saving time corrections may be applied.  If they are applied, the
95 *     offsets from the GMT must be saved in the 'tm_params' field so that
96 *     all the information is available to reconstruct GMT.
97 *
98 *     Notes on porting: PRExplodedTime corrresponds to struct tm in
99 *     ANSI C, with the following differences:
100 *       - an additional field tm_usec;
101 *       - replacing tm_isdst by tm_params;
102 *       - the month field is spelled tm_month, not tm_mon;
103 *       - we use absolute year, AD, not the year since 1900.
104 *     The corresponding type in NSPR 1.0 is called PRTime.  Below is
105 *     a table of date/time type correspondence in the three APIs:
106 *         API          time since epoch          time in components
107 *       ANSI C             time_t                  struct tm
108 *       NSPR 1.0           PRInt64                   PRTime
109 *       NSPR 2.0           PRTime                  PRExplodedTime
110 */
111
112typedef struct PRExplodedTime {
113    PRInt32 tm_usec;		    /* microseconds past tm_sec (0-99999)  */
114    PRInt32 tm_sec;             /* seconds past tm_min (0-61, accomodating
115                                   up to two leap seconds) */
116    PRInt32 tm_min;             /* minutes past tm_hour (0-59) */
117    PRInt32 tm_hour;            /* hours past tm_day (0-23) */
118    PRInt32 tm_mday;            /* days past tm_mon (1-31, note that it
119				                starts from 1) */
120    PRInt32 tm_month;           /* months past tm_year (0-11, Jan = 0) */
121    PRInt16 tm_year;            /* absolute year, AD (note that we do not
122				                count from 1900) */
123
124    PRInt8 tm_wday;		        /* calculated day of the week
125				                (0-6, Sun = 0) */
126    PRInt16 tm_yday;            /* calculated day of the year
127				                (0-365, Jan 1 = 0) */
128
129    PRTimeParameters tm_params;  /* time parameters used by conversion */
130} PRExplodedTime;
131
132/*
133 * PRTimeParamFn --
134 *
135 *     A function of PRTimeParamFn type returns the time zone and
136 *     daylight saving time corrections for some geographic location,
137 *     given the current time in GMT.  The input argument gmt should
138 *     point to a PRExplodedTime that is in GMT, i.e., whose
139 *     tm_params contains all 0's.
140 *
141 *     For any time zone other than GMT, the computation is intended to
142 *     consist of two steps:
143 *       - Figure out the time zone correction, tp_gmt_offset.  This number
144 *         usually depends on the geographic location only.  But it may
145 *         also depend on the current time.  For example, all of China
146 *         is one time zone right now.  But this situation may change
147 *         in the future.
148 *       - Figure out the daylight saving time correction, tp_dst_offset.
149 *         This number depends on both the geographic location and the
150 *         current time.  Most of the DST rules are expressed in local
151 *         current time.  If so, one should apply the time zone correction
152 *         to GMT before applying the DST rules.
153 */
154
155typedef PRTimeParameters (PR_CALLBACK *PRTimeParamFn)(const PRExplodedTime *gmt);
156
157/**********************************************************************/
158/****************************** FUNCTIONS *****************************/
159/**********************************************************************/
160
161/*
162 * The PR_Now routine returns the current time relative to the
163 * epoch, midnight, January 1, 1970 UTC. The units of the returned
164 * value are microseconds since the epoch.
165 *
166 * The values returned are not guaranteed to advance in a linear fashion
167 * due to the application of time correction protocols which synchronize
168 * computer clocks to some external time source. Consequently it should
169 * not be depended on for interval timing.
170 *
171 * The implementation is machine dependent.
172 * Cf. time_t time(time_t *tp) in ANSI C.
173 */
174#if defined(HAVE_WATCOM_BUG_2)
175PRTime __pascal __export __loadds
176#else
177NSPR_API(PRTime)
178#endif
179PR_Now(void);
180
181/*
182 * Expand time binding it to time parameters provided by PRTimeParamFn.
183 * The calculation is envisoned to proceed in the following steps:
184 *   - From given PRTime, calculate PRExplodedTime in GMT
185 *   - Apply the given PRTimeParamFn to the GMT that we just calculated
186 *     to obtain PRTimeParameters.
187 *   - Add the PRTimeParameters offsets to GMT to get the local time
188 *     as PRExplodedTime.
189 */
190
191NSPR_API(void) PR_ExplodeTime(
192    PRTime usecs, PRTimeParamFn params, PRExplodedTime *exploded);
193
194/* Reverse operation of PR_ExplodeTime */
195#if defined(HAVE_WATCOM_BUG_2)
196PRTime __pascal __export __loadds
197#else
198NSPR_API(PRTime)
199#endif
200PR_ImplodeTime(const PRExplodedTime *exploded);
201
202/*
203 * Adjust exploded time to normalize field overflows after manipulation.
204 * Note that the following fields of PRExplodedTime should not be
205 * manipulated:
206 *   - tm_month and tm_year: because the number of days in a month and
207 *     number of days in a year are not constant, it is ambiguous to
208 *     manipulate the month and year fields, although one may be tempted
209 *     to.  For example, what does "a month from January 31st" mean?
210 *   - tm_wday and tm_yday: these fields are calculated by NSPR.  Users
211 *     should treat them as "read-only".
212 */
213
214NSPR_API(void) PR_NormalizeTime(
215    PRExplodedTime *exploded, PRTimeParamFn params);
216
217/**********************************************************************/
218/*********************** TIME PARAMETER FUNCTIONS *********************/
219/**********************************************************************/
220
221/* Time parameters that suit current host machine */
222NSPR_API(PRTimeParameters) PR_LocalTimeParameters(const PRExplodedTime *gmt);
223
224/* Time parameters that represent Greenwich Mean Time */
225NSPR_API(PRTimeParameters) PR_GMTParameters(const PRExplodedTime *gmt);
226
227/*
228 * Time parameters that represent the US Pacific Time Zone, with the
229 * current daylight saving time rules (for testing only)
230 */
231NSPR_API(PRTimeParameters) PR_USPacificTimeParameters(const PRExplodedTime *gmt);
232
233/*
234 * This parses a time/date string into a PRTime
235 * (microseconds after "1-Jan-1970 00:00:00 GMT").
236 * It returns PR_SUCCESS on success, and PR_FAILURE
237 * if the time/date string can't be parsed.
238 *
239 * Many formats are handled, including:
240 *
241 *   14 Apr 89 03:20:12
242 *   14 Apr 89 03:20 GMT
243 *   Fri, 17 Mar 89 4:01:33
244 *   Fri, 17 Mar 89 4:01 GMT
245 *   Mon Jan 16 16:12 PDT 1989
246 *   Mon Jan 16 16:12 +0130 1989
247 *   6 May 1992 16:41-JST (Wednesday)
248 *   22-AUG-1993 10:59:12.82
249 *   22-AUG-1993 10:59pm
250 *   22-AUG-1993 12:59am
251 *   22-AUG-1993 12:59 PM
252 *   Friday, August 04, 1995 3:54 PM
253 *   06/21/95 04:24:34 PM
254 *   20/06/95 21:07
255 *   95-06-08 19:32:48 EDT
256 *
257 * If the input string doesn't contain a description of the timezone,
258 * we consult the `default_to_gmt' to decide whether the string should
259 * be interpreted relative to the local time zone (PR_FALSE) or GMT (PR_TRUE).
260 * The correct value for this argument depends on what standard specified
261 * the time string which you are parsing.
262 */
263
264NSPR_API(PRStatus) PR_ParseTimeString (
265	const char *string,
266	PRBool default_to_gmt,
267	PRTime *result);
268
269/*
270 * FIXME: should we also have a formatting function, such as asctime, ctime,
271 * and strftime in standard C library?  But this would involve
272 * internationalization issues.  Might want to provide a US English version.
273 */
274
275/**********************************************************************/
276/*********************** OLD COMPATIBILITYFUNCTIONS *******************/
277/**********************************************************************/
278#ifndef NO_NSPR_10_SUPPORT
279
280/* Format a time value into a buffer. Same semantics as strftime() */
281NSPR_API(PRUint32) PR_FormatTime(char *buf, int buflen, const char *fmt,
282                                           const PRExplodedTime *tm);
283
284/* Format a time value into a buffer. Time is always in US English format, regardless
285 * of locale setting.
286 */
287NSPR_API(PRUint32)
288PR_FormatTimeUSEnglish( char* buf, PRUint32 bufSize,
289                        const char* format, const PRExplodedTime* tm );
290
291#endif /* NO_NSPR_10_SUPPORT */
292
293PR_END_EXTERN_C
294
295#endif /* prtime_h___ */
296