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comparison: nsprpub/pr/include/prtime.h
nsprpub/pr/include/prtime.h
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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 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 NSPR_API(void) PR_ExplodeTime( | |
| 159 PRTime usecs, PRTimeParamFn params, PRExplodedTime *exploded); | |
| 160 | |
| 161 /* Reverse operation of PR_ExplodeTime */ | |
| 162 NSPR_API(PRTime) | |
| 163 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 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 NSPR_API(PRTimeParameters) PR_LocalTimeParameters(const PRExplodedTime *gmt); | |
| 186 | |
| 187 /* Time parameters that represent Greenwich Mean Time */ | |
| 188 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 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 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 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 NSPR_API(PRUint32) PR_FormatTime(char *buf, int buflen, const char *fmt, | |
| 251 const PRExplodedTime *tm); | |
| 252 | |
| 253 /* Format a time value into a buffer. Time is always in US English format, regardless | |
| 254 * of locale setting. | |
| 255 */ | |
| 256 NSPR_API(PRUint32) | |
| 257 PR_FormatTimeUSEnglish( char* buf, PRUint32 bufSize, | |
| 258 const char* format, const PRExplodedTime* tm ); | |
| 259 | |
| 260 PR_END_EXTERN_C | |
| 261 | |
| 262 #endif /* prtime_h___ */ |
