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Diffstat (limited to 'nsprpub/pr/include/prtime.h')
| -rw-r--r-- | nsprpub/pr/include/prtime.h | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/nsprpub/pr/include/prtime.h b/nsprpub/pr/include/prtime.h new file mode 100644 index 0000000000..917a16159d --- /dev/null +++ b/nsprpub/pr/include/prtime.h @@ -0,0 +1,262 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* + *---------------------------------------------------------------------- + * + * prtime.h -- + * + * NSPR date and time functions + * + *----------------------------------------------------------------------- + */ + +#ifndef prtime_h___ +#define prtime_h___ + +#include "prlong.h" + +PR_BEGIN_EXTERN_C + +/**********************************************************************/ +/************************* TYPES AND CONSTANTS ************************/ +/**********************************************************************/ + +#define PR_MSEC_PER_SEC 1000L +#define PR_USEC_PER_SEC 1000000L +#define PR_NSEC_PER_SEC 1000000000L +#define PR_USEC_PER_MSEC 1000L +#define PR_NSEC_PER_MSEC 1000000L + +/* + * PRTime -- + * + * NSPR represents basic time as 64-bit signed integers relative + * to midnight (00:00:00), January 1, 1970 Greenwich Mean Time (GMT). + * (GMT is also known as Coordinated Universal Time, UTC.) + * The units of time are in microseconds. Negative times are allowed + * to represent times prior to the January 1970 epoch. Such values are + * intended to be exported to other systems or converted to human + * readable form. + * + * Notes on porting: PRTime corresponds to time_t in ANSI C. NSPR 1.0 + * simply uses PRInt64. + */ + +typedef PRInt64 PRTime; + +/* + * Time zone and daylight saving time corrections applied to GMT to + * obtain the local time of some geographic location + */ + +typedef struct PRTimeParameters { + PRInt32 tp_gmt_offset; /* the offset from GMT in seconds */ + PRInt32 tp_dst_offset; /* contribution of DST in seconds */ +} PRTimeParameters; + +/* + * PRExplodedTime -- + * + * Time broken down into human-readable components such as year, month, + * day, hour, minute, second, and microsecond. Time zone and daylight + * saving time corrections may be applied. If they are applied, the + * offsets from the GMT must be saved in the 'tm_params' field so that + * all the information is available to reconstruct GMT. + * + * Notes on porting: PRExplodedTime corrresponds to struct tm in + * ANSI C, with the following differences: + * - an additional field tm_usec; + * - replacing tm_isdst by tm_params; + * - the month field is spelled tm_month, not tm_mon; + * - we use absolute year, AD, not the year since 1900. + * The corresponding type in NSPR 1.0 is called PRTime. Below is + * a table of date/time type correspondence in the three APIs: + * API time since epoch time in components + * ANSI C time_t struct tm + * NSPR 1.0 PRInt64 PRTime + * NSPR 2.0 PRTime PRExplodedTime + */ + +typedef struct PRExplodedTime { + PRInt32 tm_usec; /* microseconds past tm_sec (0-99999) */ + PRInt32 tm_sec; /* seconds past tm_min (0-61, accomodating + up to two leap seconds) */ + PRInt32 tm_min; /* minutes past tm_hour (0-59) */ + PRInt32 tm_hour; /* hours past tm_day (0-23) */ + PRInt32 tm_mday; /* days past tm_mon (1-31, note that it + starts from 1) */ + PRInt32 tm_month; /* months past tm_year (0-11, Jan = 0) */ + PRInt16 tm_year; /* absolute year, AD (note that we do not + count from 1900) */ + + PRInt8 tm_wday; /* calculated day of the week + (0-6, Sun = 0) */ + PRInt16 tm_yday; /* calculated day of the year + (0-365, Jan 1 = 0) */ + + PRTimeParameters tm_params; /* time parameters used by conversion */ +} PRExplodedTime; + +/* + * PRTimeParamFn -- + * + * A function of PRTimeParamFn type returns the time zone and + * daylight saving time corrections for some geographic location, + * given the current time in GMT. The input argument gmt should + * point to a PRExplodedTime that is in GMT, i.e., whose + * tm_params contains all 0's. + * + * For any time zone other than GMT, the computation is intended to + * consist of two steps: + * - Figure out the time zone correction, tp_gmt_offset. This number + * usually depends on the geographic location only. But it may + * also depend on the current time. For example, all of China + * is one time zone right now. But this situation may change + * in the future. + * - Figure out the daylight saving time correction, tp_dst_offset. + * This number depends on both the geographic location and the + * current time. Most of the DST rules are expressed in local + * current time. If so, one should apply the time zone correction + * to GMT before applying the DST rules. + */ + +typedef PRTimeParameters (PR_CALLBACK *PRTimeParamFn)(const PRExplodedTime *gmt); + +/**********************************************************************/ +/****************************** FUNCTIONS *****************************/ +/**********************************************************************/ + +/* + * The PR_Now routine returns the current time relative to the + * epoch, midnight, January 1, 1970 UTC. The units of the returned + * value are microseconds since the epoch. + * + * The values returned are not guaranteed to advance in a linear fashion + * due to the application of time correction protocols which synchronize + * computer clocks to some external time source. Consequently it should + * not be depended on for interval timing. + * + * The implementation is machine dependent. + * Cf. time_t time(time_t *tp) in ANSI C. + */ +NSPR_API(PRTime) +PR_Now(void); + +/* + * Expand time binding it to time parameters provided by PRTimeParamFn. + * The calculation is envisoned to proceed in the following steps: + * - From given PRTime, calculate PRExplodedTime in GMT + * - Apply the given PRTimeParamFn to the GMT that we just calculated + * to obtain PRTimeParameters. + * - Add the PRTimeParameters offsets to GMT to get the local time + * as PRExplodedTime. + */ + +NSPR_API(void) PR_ExplodeTime( + PRTime usecs, PRTimeParamFn params, PRExplodedTime *exploded); + +/* Reverse operation of PR_ExplodeTime */ +NSPR_API(PRTime) +PR_ImplodeTime(const PRExplodedTime *exploded); + +/* + * Adjust exploded time to normalize field overflows after manipulation. + * Note that the following fields of PRExplodedTime should not be + * manipulated: + * - tm_month and tm_year: because the number of days in a month and + * number of days in a year are not constant, it is ambiguous to + * manipulate the month and year fields, although one may be tempted + * to. For example, what does "a month from January 31st" mean? + * - tm_wday and tm_yday: these fields are calculated by NSPR. Users + * should treat them as "read-only". + */ + +NSPR_API(void) PR_NormalizeTime( + PRExplodedTime *exploded, PRTimeParamFn params); + +/**********************************************************************/ +/*********************** TIME PARAMETER FUNCTIONS *********************/ +/**********************************************************************/ + +/* Time parameters that suit current host machine */ +NSPR_API(PRTimeParameters) PR_LocalTimeParameters(const PRExplodedTime *gmt); + +/* Time parameters that represent Greenwich Mean Time */ +NSPR_API(PRTimeParameters) PR_GMTParameters(const PRExplodedTime *gmt); + +/* + * Time parameters that represent the US Pacific Time Zone, with the + * current daylight saving time rules (for testing only) + */ +NSPR_API(PRTimeParameters) PR_USPacificTimeParameters(const PRExplodedTime *gmt); + +/* + * This parses a time/date string into a PRExplodedTime + * struct. It populates all fields but it can't split + * the offset from UTC into tp_gmt_offset and tp_dst_offset in + * most cases (exceptions: PST/PDT, MST/MDT, CST/CDT, EST/EDT, GMT/BST). + * In those cases tp_gmt_offset will be the sum of these two and + * tp_dst_offset will be 0. + * It returns PR_SUCCESS on success, and PR_FAILURE + * if the time/date string can't be parsed. + * + * Many formats are handled, including: + * + * 14 Apr 89 03:20:12 + * 14 Apr 89 03:20 GMT + * Fri, 17 Mar 89 4:01:33 + * Fri, 17 Mar 89 4:01 GMT + * Mon Jan 16 16:12 PDT 1989 + * Mon Jan 16 16:12 +0130 1989 + * 6 May 1992 16:41-JST (Wednesday) + * 22-AUG-1993 10:59:12.82 + * 22-AUG-1993 10:59pm + * 22-AUG-1993 12:59am + * 22-AUG-1993 12:59 PM + * Friday, August 04, 1995 3:54 PM + * 06/21/95 04:24:34 PM + * 20/06/95 21:07 + * 95-06-08 19:32:48 EDT + * + * If the input string doesn't contain a description of the timezone, + * we consult the `default_to_gmt' to decide whether the string should + * be interpreted relative to the local time zone (PR_FALSE) or GMT (PR_TRUE). + * The correct value for this argument depends on what standard specified + * the time string which you are parsing. + */ + +NSPR_API(PRStatus) PR_ParseTimeStringToExplodedTime ( + const char *string, + PRBool default_to_gmt, + PRExplodedTime *result); + +/* + * This uses PR_ParseTimeStringToExplodedTime to parse + * a time/date string and PR_ImplodeTime to transform it into + * a PRTime (microseconds after "1-Jan-1970 00:00:00 GMT"). + * It returns PR_SUCCESS on success, and PR_FAILURE + * if the time/date string can't be parsed. + */ + +NSPR_API(PRStatus) PR_ParseTimeString ( + const char *string, + PRBool default_to_gmt, + PRTime *result); + +/* Format a time value into a buffer. Same semantics as strftime() */ +NSPR_API(PRUint32) PR_FormatTime(char *buf, int buflen, const char *fmt, + const PRExplodedTime *time); + +/* Format a time value into a buffer. Time is always in US English format, + * regardless of locale setting. + */ +NSPR_API(PRUint32) +PR_FormatTimeUSEnglish(char *buf, PRUint32 bufSize, + const char *format, const PRExplodedTime *time); + +PR_END_EXTERN_C + +#endif /* prtime_h___ */ |