1/*	$NetBSD$	*/
2
3/*
4 * Copyright (c) 1997 Kungliga Tekniska H��gskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "der_locl.h"
37
38__RCSID("$NetBSD$");
39
40static int
41is_leap(unsigned y)
42{
43    y += 1900;
44    return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0);
45}
46
47static const unsigned ndays[2][12] ={
48    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
49    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
50
51/*
52 * This is a simplifed version of timegm(3) that doesn't accept out of
53 * bound values that timegm(3) normally accepts but those are not
54 * valid in asn1 encodings.
55 */
56
57time_t
58_der_timegm (struct tm *tm)
59{
60  time_t res = 0;
61  unsigned i;
62
63  if (tm->tm_year < 0)
64      return -1;
65  if (tm->tm_mon < 0 || tm->tm_mon > 11)
66      return -1;
67  if (tm->tm_mday < 1 || tm->tm_mday > ndays[is_leap(tm->tm_year)][tm->tm_mon])
68      return -1;
69  if (tm->tm_hour < 0 || tm->tm_hour > 23)
70      return -1;
71  if (tm->tm_min < 0 || tm->tm_min > 59)
72      return -1;
73  if (tm->tm_sec < 0 || tm->tm_sec > 59)
74      return -1;
75
76  for (i = 70; i < tm->tm_year; ++i)
77    res += is_leap(i) ? 366 : 365;
78
79  for (i = 0; i < tm->tm_mon; ++i)
80    res += ndays[is_leap(tm->tm_year)][i];
81  res += tm->tm_mday - 1;
82  res *= 24;
83  res += tm->tm_hour;
84  res *= 60;
85  res += tm->tm_min;
86  res *= 60;
87  res += tm->tm_sec;
88  return res;
89}
90
91struct tm *
92_der_gmtime(time_t t, struct tm *tm)
93{
94    time_t secday = t % (3600 * 24);
95    time_t days = t / (3600 * 24);
96
97    memset(tm, 0, sizeof(*tm));
98
99    tm->tm_sec = secday % 60;
100    tm->tm_min = (secday % 3600) / 60;
101    tm->tm_hour = secday / 3600;
102
103    tm->tm_year = 70;
104    while(1) {
105	unsigned dayinyear = (is_leap(tm->tm_year) ? 366 : 365);
106	if (days < dayinyear)
107	    break;
108	tm->tm_year += 1;
109	days -= dayinyear;
110    }
111    tm->tm_mon = 0;
112
113    while (1) {
114	unsigned daysinmonth = ndays[is_leap(tm->tm_year)][tm->tm_mon];
115	if (days < daysinmonth)
116	    break;
117	days -= daysinmonth;
118	tm->tm_mon++;
119    }
120    tm->tm_mday = days + 1;
121
122    return tm;
123}
124