prtime.h
上传用户:goldcmy89
上传日期:2017-12-03
资源大小:2246k
文件大小:11k
- /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
- /* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is the Netscape Portable Runtime (NSPR).
- *
- * The Initial Developer of the Original Code is
- * Netscape Communications Corporation.
- * Portions created by the Initial Developer are Copyright (C) 1998-2000
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
- /*
- *----------------------------------------------------------------------
- *
- * 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 1000UL
- #define PR_USEC_PER_SEC 1000000UL
- #define PR_NSEC_PER_SEC 1000000000UL
- #define PR_USEC_PER_MSEC 1000UL
- #define PR_NSEC_PER_MSEC 1000000UL
- /*
- * 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.
- */
- #if defined(HAVE_WATCOM_BUG_2)
- PRTime __pascal __export __loadds
- #else
- NSPR_API(PRTime)
- #endif
- 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 */
- #if defined(HAVE_WATCOM_BUG_2)
- PRTime __pascal __export __loadds
- #else
- NSPR_API(PRTime)
- #endif
- 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 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.
- *
- * 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_ParseTimeString (
- const char *string,
- PRBool default_to_gmt,
- PRTime *result);
- /*
- * FIXME: should we also have a formatting function, such as asctime, ctime,
- * and strftime in standard C library? But this would involve
- * internationalization issues. Might want to provide a US English version.
- */
- /**********************************************************************/
- /*********************** OLD COMPATIBILITYFUNCTIONS *******************/
- /**********************************************************************/
- #ifndef NO_NSPR_10_SUPPORT
- /* 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 *tm);
- /* 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* tm );
- #endif /* NO_NSPR_10_SUPPORT */
- PR_END_EXTERN_C
- #endif /* prtime_h___ */