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1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 : /* This Source Code Form is subject to the terms of the Mozilla Public
3 : * License, v. 2.0. If a copy of the MPL was not distributed with this
4 : * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5 :
6 : /*
7 : *----------------------------------------------------------------------
8 : *
9 : * prtime.h --
10 : *
11 : * NSPR date and time functions
12 : *
13 : *-----------------------------------------------------------------------
14 : */
15 :
16 : #ifndef prtime_h___
17 : #define prtime_h___
18 :
19 : #include "prlong.h"
20 :
21 : PR_BEGIN_EXTERN_C
22 :
23 : /**********************************************************************/
24 : /************************* TYPES AND CONSTANTS ************************/
25 : /**********************************************************************/
26 :
27 : #define PR_MSEC_PER_SEC 1000L
28 : #define PR_USEC_PER_SEC 1000000L
29 : #define PR_NSEC_PER_SEC 1000000000L
30 : #define PR_USEC_PER_MSEC 1000L
31 : #define PR_NSEC_PER_MSEC 1000000L
32 :
33 : /*
34 : * PRTime --
35 : *
36 : * NSPR represents basic time as 64-bit signed integers relative
37 : * to midnight (00:00:00), January 1, 1970 Greenwich Mean Time (GMT).
38 : * (GMT is also known as Coordinated Universal Time, UTC.)
39 : * The units of time are in microseconds. Negative times are allowed
40 : * to represent times prior to the January 1970 epoch. Such values are
41 : * intended to be exported to other systems or converted to human
42 : * readable form.
43 : *
44 : * Notes on porting: PRTime corresponds to time_t in ANSI C. NSPR 1.0
45 : * simply uses PRInt64.
46 : */
47 :
48 : typedef PRInt64 PRTime;
49 :
50 : /*
51 : * Time zone and daylight saving time corrections applied to GMT to
52 : * obtain the local time of some geographic location
53 : */
54 :
55 : typedef struct PRTimeParameters {
56 : PRInt32 tp_gmt_offset; /* the offset from GMT in seconds */
57 : PRInt32 tp_dst_offset; /* contribution of DST in seconds */
58 : } PRTimeParameters;
59 :
60 : /*
61 : * PRExplodedTime --
62 : *
63 : * Time broken down into human-readable components such as year, month,
64 : * day, hour, minute, second, and microsecond. Time zone and daylight
65 : * saving time corrections may be applied. If they are applied, the
66 : * offsets from the GMT must be saved in the 'tm_params' field so that
67 : * all the information is available to reconstruct GMT.
68 : *
69 : * Notes on porting: PRExplodedTime corrresponds to struct tm in
70 : * ANSI C, with the following differences:
71 : * - an additional field tm_usec;
72 : * - replacing tm_isdst by tm_params;
73 : * - the month field is spelled tm_month, not tm_mon;
74 : * - we use absolute year, AD, not the year since 1900.
75 : * The corresponding type in NSPR 1.0 is called PRTime. Below is
76 : * a table of date/time type correspondence in the three APIs:
77 : * API time since epoch time in components
78 : * ANSI C time_t struct tm
79 : * NSPR 1.0 PRInt64 PRTime
80 : * NSPR 2.0 PRTime PRExplodedTime
81 : */
82 :
83 : typedef struct PRExplodedTime {
84 : PRInt32 tm_usec; /* microseconds past tm_sec (0-99999) */
85 : PRInt32 tm_sec; /* seconds past tm_min (0-61, accomodating
86 : up to two leap seconds) */
87 : PRInt32 tm_min; /* minutes past tm_hour (0-59) */
88 : PRInt32 tm_hour; /* hours past tm_day (0-23) */
89 : PRInt32 tm_mday; /* days past tm_mon (1-31, note that it
90 : starts from 1) */
91 : PRInt32 tm_month; /* months past tm_year (0-11, Jan = 0) */
92 : PRInt16 tm_year; /* absolute year, AD (note that we do not
93 : count from 1900) */
94 :
95 : PRInt8 tm_wday; /* calculated day of the week
96 : (0-6, Sun = 0) */
97 : PRInt16 tm_yday; /* calculated day of the year
98 : (0-365, Jan 1 = 0) */
99 :
100 : PRTimeParameters tm_params; /* time parameters used by conversion */
101 : } PRExplodedTime;
102 :
103 : /*
104 : * PRTimeParamFn --
105 : *
106 : * A function of PRTimeParamFn type returns the time zone and
107 : * daylight saving time corrections for some geographic location,
108 : * given the current time in GMT. The input argument gmt should
109 : * point to a PRExplodedTime that is in GMT, i.e., whose
110 : * tm_params contains all 0's.
111 : *
112 : * For any time zone other than GMT, the computation is intended to
113 : * consist of two steps:
114 : * - Figure out the time zone correction, tp_gmt_offset. This number
115 : * usually depends on the geographic location only. But it may
116 : * also depend on the current time. For example, all of China
117 : * is one time zone right now. But this situation may change
118 : * in the future.
119 : * - Figure out the daylight saving time correction, tp_dst_offset.
120 : * This number depends on both the geographic location and the
121 : * current time. Most of the DST rules are expressed in local
122 : * current time. If so, one should apply the time zone correction
123 : * to GMT before applying the DST rules.
124 : */
125 :
126 : typedef PRTimeParameters (PR_CALLBACK *PRTimeParamFn)(const PRExplodedTime *gmt);
127 :
128 : /**********************************************************************/
129 : /****************************** FUNCTIONS *****************************/
130 : /**********************************************************************/
131 :
132 : /*
133 : * The PR_Now routine returns the current time relative to the
134 : * epoch, midnight, January 1, 1970 UTC. The units of the returned
135 : * value are microseconds since the epoch.
136 : *
137 : * The values returned are not guaranteed to advance in a linear fashion
138 : * due to the application of time correction protocols which synchronize
139 : * computer clocks to some external time source. Consequently it should
140 : * not be depended on for interval timing.
141 : *
142 : * The implementation is machine dependent.
143 : * Cf. time_t time(time_t *tp) in ANSI C.
144 : */
145 : NSPR_API(PRTime)
146 4749 : PR_Now(void);
147 :
148 : /*
149 : * Expand time binding it to time parameters provided by PRTimeParamFn.
150 : * The calculation is envisoned to proceed in the following steps:
151 : * - From given PRTime, calculate PRExplodedTime in GMT
152 : * - Apply the given PRTimeParamFn to the GMT that we just calculated
153 : * to obtain PRTimeParameters.
154 : * - Add the PRTimeParameters offsets to GMT to get the local time
155 : * as PRExplodedTime.
156 : */
157 :
158 25 : NSPR_API(void) PR_ExplodeTime(
159 : PRTime usecs, PRTimeParamFn params, PRExplodedTime *exploded);
160 :
161 : /* Reverse operation of PR_ExplodeTime */
162 : NSPR_API(PRTime)
163 35 : PR_ImplodeTime(const PRExplodedTime *exploded);
164 :
165 : /*
166 : * Adjust exploded time to normalize field overflows after manipulation.
167 : * Note that the following fields of PRExplodedTime should not be
168 : * manipulated:
169 : * - tm_month and tm_year: because the number of days in a month and
170 : * number of days in a year are not constant, it is ambiguous to
171 : * manipulate the month and year fields, although one may be tempted
172 : * to. For example, what does "a month from January 31st" mean?
173 : * - tm_wday and tm_yday: these fields are calculated by NSPR. Users
174 : * should treat them as "read-only".
175 : */
176 :
177 45 : NSPR_API(void) PR_NormalizeTime(
178 : PRExplodedTime *exploded, PRTimeParamFn params);
179 :
180 : /**********************************************************************/
181 : /*********************** TIME PARAMETER FUNCTIONS *********************/
182 : /**********************************************************************/
183 :
184 : /* Time parameters that suit current host machine */
185 25 : NSPR_API(PRTimeParameters) PR_LocalTimeParameters(const PRExplodedTime *gmt);
186 :
187 : /* Time parameters that represent Greenwich Mean Time */
188 45 : NSPR_API(PRTimeParameters) PR_GMTParameters(const PRExplodedTime *gmt);
189 :
190 : /*
191 : * Time parameters that represent the US Pacific Time Zone, with the
192 : * current daylight saving time rules (for testing only)
193 : */
194 0 : NSPR_API(PRTimeParameters) PR_USPacificTimeParameters(const PRExplodedTime *gmt);
195 :
196 : /*
197 : * This parses a time/date string into a PRExplodedTime
198 : * struct. It populates all fields but it can't split
199 : * the offset from UTC into tp_gmt_offset and tp_dst_offset in
200 : * most cases (exceptions: PST/PDT, MST/MDT, CST/CDT, EST/EDT, GMT/BST).
201 : * In those cases tp_gmt_offset will be the sum of these two and
202 : * tp_dst_offset will be 0.
203 : * It returns PR_SUCCESS on success, and PR_FAILURE
204 : * if the time/date string can't be parsed.
205 : *
206 : * Many formats are handled, including:
207 : *
208 : * 14 Apr 89 03:20:12
209 : * 14 Apr 89 03:20 GMT
210 : * Fri, 17 Mar 89 4:01:33
211 : * Fri, 17 Mar 89 4:01 GMT
212 : * Mon Jan 16 16:12 PDT 1989
213 : * Mon Jan 16 16:12 +0130 1989
214 : * 6 May 1992 16:41-JST (Wednesday)
215 : * 22-AUG-1993 10:59:12.82
216 : * 22-AUG-1993 10:59pm
217 : * 22-AUG-1993 12:59am
218 : * 22-AUG-1993 12:59 PM
219 : * Friday, August 04, 1995 3:54 PM
220 : * 06/21/95 04:24:34 PM
221 : * 20/06/95 21:07
222 : * 95-06-08 19:32:48 EDT
223 : *
224 : * If the input string doesn't contain a description of the timezone,
225 : * we consult the `default_to_gmt' to decide whether the string should
226 : * be interpreted relative to the local time zone (PR_FALSE) or GMT (PR_TRUE).
227 : * The correct value for this argument depends on what standard specified
228 : * the time string which you are parsing.
229 : */
230 :
231 10 : NSPR_API(PRStatus) PR_ParseTimeStringToExplodedTime (
232 : const char *string,
233 : PRBool default_to_gmt,
234 : PRExplodedTime *result);
235 :
236 : /*
237 : * This uses PR_ParseTimeStringToExplodedTime to parse
238 : * a time/date string and PR_ImplodeTime to transform it into
239 : * a PRTime (microseconds after "1-Jan-1970 00:00:00 GMT").
240 : * It returns PR_SUCCESS on success, and PR_FAILURE
241 : * if the time/date string can't be parsed.
242 : */
243 :
244 10 : NSPR_API(PRStatus) PR_ParseTimeString (
245 : const char *string,
246 : PRBool default_to_gmt,
247 : PRTime *result);
248 :
249 : /* Format a time value into a buffer. Same semantics as strftime() */
250 0 : NSPR_API(PRUint32) PR_FormatTime(char *buf, int buflen, const char *fmt,
251 : const PRExplodedTime *time);
252 :
253 : /* Format a time value into a buffer. Time is always in US English format,
254 : * regardless of locale setting.
255 : */
256 : NSPR_API(PRUint32)
257 0 : PR_FormatTimeUSEnglish(char *buf, PRUint32 bufSize,
258 : const char *format, const PRExplodedTime *time);
259 :
260 : PR_END_EXTERN_C
261 :
262 : #endif /* prtime_h___ */
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