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+/* -*- 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___ */