/* 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. */ 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. * Below is a table of date/time type correspondence in the two APIs: * API time since epoch time in components * ANSI C time_t struct tm * NSPR 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___ */