1/*	$NetBSD$	*/
2
3/*
4 * Copyright (C) 2004-2009  Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (C) 1998-2001  Internet Software Consortium.
6 *
7 * Permission to use, copy, modify, and/or distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
12 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
13 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
14 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
16 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
17 * PERFORMANCE OF THIS SOFTWARE.
18 */
19
20/* Id: time.h,v 1.38.56.2 2009/01/05 23:47:23 tbox Exp */
21
22#ifndef ISC_TIME_H
23#define ISC_TIME_H 1
24
25/*! \file */
26
27#include <isc/lang.h>
28#include <isc/types.h>
29
30/***
31 *** Intervals
32 ***/
33
34/*!
35 *  \brief
36 * The contents of this structure are private, and MUST NOT be accessed
37 * directly by callers.
38 *
39 * The contents are exposed only to allow callers to avoid dynamic allocation.
40 */
41struct isc_interval {
42	unsigned int seconds;
43	unsigned int nanoseconds;
44};
45
46extern isc_interval_t *isc_interval_zero;
47
48ISC_LANG_BEGINDECLS
49
50void
51isc_interval_set(isc_interval_t *i,
52		 unsigned int seconds, unsigned int nanoseconds);
53/*%<
54 * Set 'i' to a value representing an interval of 'seconds' seconds and
55 * 'nanoseconds' nanoseconds, suitable for use in isc_time_add() and
56 * isc_time_subtract().
57 *
58 * Requires:
59 *
60 *\li	't' is a valid pointer.
61 *\li	nanoseconds < 1000000000.
62 */
63
64isc_boolean_t
65isc_interval_iszero(const isc_interval_t *i);
66/*%<
67 * Returns ISC_TRUE iff. 'i' is the zero interval.
68 *
69 * Requires:
70 *
71 *\li	'i' is a valid pointer.
72 */
73
74/***
75 *** Absolute Times
76 ***/
77
78/*%
79 * The contents of this structure are private, and MUST NOT be accessed
80 * directly by callers.
81 *
82 * The contents are exposed only to allow callers to avoid dynamic allocation.
83 */
84
85struct isc_time {
86	unsigned int	seconds;
87	unsigned int	nanoseconds;
88};
89
90extern isc_time_t *isc_time_epoch;
91
92void
93isc_time_set(isc_time_t *t, unsigned int seconds, unsigned int nanoseconds);
94/*%<
95 * Set 't' to a value which represents the given number of seconds and
96 * nanoseconds since 00:00:00 January 1, 1970, UTC.
97 *
98 * Notes:
99 *\li	The Unix version of this call is equivalent to:
100 *\code
101 *	isc_time_settoepoch(t);
102 *	isc_interval_set(i, seconds, nanoseconds);
103 *	isc_time_add(t, i, t);
104 *\endcode
105 *
106 * Requires:
107 *\li	't' is a valid pointer.
108 *\li	nanoseconds < 1000000000.
109 */
110
111void
112isc_time_settoepoch(isc_time_t *t);
113/*%<
114 * Set 't' to the time of the epoch.
115 *
116 * Notes:
117 *\li	The date of the epoch is platform-dependent.
118 *
119 * Requires:
120 *
121 *\li	't' is a valid pointer.
122 */
123
124isc_boolean_t
125isc_time_isepoch(const isc_time_t *t);
126/*%<
127 * Returns ISC_TRUE iff. 't' is the epoch ("time zero").
128 *
129 * Requires:
130 *
131 *\li	't' is a valid pointer.
132 */
133
134isc_result_t
135isc_time_now(isc_time_t *t);
136/*%<
137 * Set 't' to the current absolute time.
138 *
139 * Requires:
140 *
141 *\li	't' is a valid pointer.
142 *
143 * Returns:
144 *
145 *\li	Success
146 *\li	Unexpected error
147 *		Getting the time from the system failed.
148 *\li	Out of range
149 *		The time from the system is too large to be represented
150 *		in the current definition of isc_time_t.
151 */
152
153isc_result_t
154isc_time_nowplusinterval(isc_time_t *t, const isc_interval_t *i);
155/*%<
156 * Set *t to the current absolute time + i.
157 *
158 * Note:
159 *\li	This call is equivalent to:
160 *
161 *\code
162 *		isc_time_now(t);
163 *		isc_time_add(t, i, t);
164 *\endcode
165 *
166 * Requires:
167 *
168 *\li	't' and 'i' are valid pointers.
169 *
170 * Returns:
171 *
172 *\li	Success
173 *\li	Unexpected error
174 *		Getting the time from the system failed.
175 *\li	Out of range
176 *		The interval added to the time from the system is too large to
177 *		be represented in the current definition of isc_time_t.
178 */
179
180int
181isc_time_compare(const isc_time_t *t1, const isc_time_t *t2);
182/*%<
183 * Compare the times referenced by 't1' and 't2'
184 *
185 * Requires:
186 *
187 *\li	't1' and 't2' are valid pointers.
188 *
189 * Returns:
190 *
191 *\li	-1		t1 < t2		(comparing times, not pointers)
192 *\li	0		t1 = t2
193 *\li	1		t1 > t2
194 */
195
196isc_result_t
197isc_time_add(const isc_time_t *t, const isc_interval_t *i, isc_time_t *result);
198/*%<
199 * Add 'i' to 't', storing the result in 'result'.
200 *
201 * Requires:
202 *
203 *\li	't', 'i', and 'result' are valid pointers.
204 *
205 * Returns:
206 *\li	Success
207 *\li	Out of range
208 * 		The interval added to the time is too large to
209 *		be represented in the current definition of isc_time_t.
210 */
211
212isc_result_t
213isc_time_subtract(const isc_time_t *t, const isc_interval_t *i,
214		  isc_time_t *result);
215/*%<
216 * Subtract 'i' from 't', storing the result in 'result'.
217 *
218 * Requires:
219 *
220 *\li	't', 'i', and 'result' are valid pointers.
221 *
222 * Returns:
223 *\li	Success
224 *\li	Out of range
225 *		The interval is larger than the time since the epoch.
226 */
227
228isc_uint64_t
229isc_time_microdiff(const isc_time_t *t1, const isc_time_t *t2);
230/*%<
231 * Find the difference in microseconds between time t1 and time t2.
232 * t2 is the subtrahend of t1; ie, difference = t1 - t2.
233 *
234 * Requires:
235 *
236 *\li	't1' and 't2' are valid pointers.
237 *
238 * Returns:
239 *\li	The difference of t1 - t2, or 0 if t1 <= t2.
240 */
241
242isc_uint32_t
243isc_time_seconds(const isc_time_t *t);
244/*%<
245 * Return the number of seconds since the epoch stored in a time structure.
246 *
247 * Requires:
248 *
249 *\li	't' is a valid pointer.
250 */
251
252isc_result_t
253isc_time_secondsastimet(const isc_time_t *t, time_t *secondsp);
254/*%<
255 * Ensure the number of seconds in an isc_time_t is representable by a time_t.
256 *
257 * Notes:
258 *\li	The number of seconds stored in an isc_time_t might be larger
259 *	than the number of seconds a time_t is able to handle.  Since
260 *	time_t is mostly opaque according to the ANSI/ISO standard
261 *	(essentially, all you can be sure of is that it is an arithmetic type,
262 *	not even necessarily integral), it can be tricky to ensure that
263 *	the isc_time_t is in the range a time_t can handle.  Use this
264 *	function in place of isc_time_seconds() any time you need to set a
265 *	time_t from an isc_time_t.
266 *
267 * Requires:
268 *\li	't' is a valid pointer.
269 *
270 * Returns:
271 *\li	Success
272 *\li	Out of range
273 */
274
275isc_uint32_t
276isc_time_nanoseconds(const isc_time_t *t);
277/*%<
278 * Return the number of nanoseconds stored in a time structure.
279 *
280 * Notes:
281 *\li	This is the number of nanoseconds in excess of the number
282 *	of seconds since the epoch; it will always be less than one
283 *	full second.
284 *
285 * Requires:
286 *\li	't' is a valid pointer.
287 *
288 * Ensures:
289 *\li	The returned value is less than 1*10^9.
290 */
291
292void
293isc_time_formattimestamp(const isc_time_t *t, char *buf, unsigned int len);
294/*%<
295 * Format the time 't' into the buffer 'buf' of length 'len',
296 * using a format like "30-Aug-2000 04:06:47.997" and the local time zone.
297 * If the text does not fit in the buffer, the result is indeterminate,
298 * but is always guaranteed to be null terminated.
299 *
300 *  Requires:
301 *\li      'len' > 0
302 *\li      'buf' points to an array of at least len chars
303 *
304 */
305
306void
307isc_time_formathttptimestamp(const isc_time_t *t, char *buf, unsigned int len);
308/*%<
309 * Format the time 't' into the buffer 'buf' of length 'len',
310 * using a format like "Mon, 30 Aug 2000 04:06:47 GMT"
311 * If the text does not fit in the buffer, the result is indeterminate,
312 * but is always guaranteed to be null terminated.
313 *
314 *  Requires:
315 *\li      'len' > 0
316 *\li      'buf' points to an array of at least len chars
317 *
318 */
319
320void
321isc_time_formatISO8601(const isc_time_t *t, char *buf, unsigned int len);
322/*%<
323 * Format the time 't' into the buffer 'buf' of length 'len',
324 * using the ISO8601 format: "yyyy-mm-ddThh:mm:ssZ"
325 * If the text does not fit in the buffer, the result is indeterminate,
326 * but is always guaranteed to be null terminated.
327 *
328 *  Requires:
329 *\li      'len' > 0
330 *\li      'buf' points to an array of at least len chars
331 *
332 */
333
334ISC_LANG_ENDDECLS
335
336#endif /* ISC_TIME_H */
337