xref: /freebsd/crypto/heimdal/lib/roken/timegm.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*
2  * Copyright (c) 1997, 2006 Kungliga Tekniska Högskolan
3  * (Royal Institute of Technology, Stockholm, Sweden).
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  *
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * 3. Neither the name of the Institute nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <config.h>
35 
36 #include "roken.h"
37 
38 static int
39 is_leap(unsigned y)
40 {
41     y += 1900;
42     return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0);
43 }
44 
45 /*
46  * XXX This is a simplifed version of timegm, it needs to support out of
47  * bounds values.
48  */
49 
50 time_t
51 rk_timegm (struct tm *tm)
52 {
53   static const unsigned ndays[2][12] ={
54     {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
55     {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
56   time_t res = 0;
57   unsigned i;
58 
59   if (tm->tm_year < 0)
60       return -1;
61   if (tm->tm_mon < 0 || tm->tm_mon > 11)
62       return -1;
63   if (tm->tm_mday < 1 || tm->tm_mday > ndays[is_leap(tm->tm_year)][tm->tm_mon])
64       return -1;
65   if (tm->tm_hour < 0 || tm->tm_hour > 23)
66       return -1;
67   if (tm->tm_min < 0 || tm->tm_min > 59)
68       return -1;
69   if (tm->tm_sec < 0 || tm->tm_sec > 59)
70       return -1;
71 
72   for (i = 70; i < tm->tm_year; ++i)
73     res += is_leap(i) ? 366 : 365;
74 
75   for (i = 0; i < tm->tm_mon; ++i)
76     res += ndays[is_leap(tm->tm_year)][i];
77   res += tm->tm_mday - 1;
78   res *= 24;
79   res += tm->tm_hour;
80   res *= 60;
81   res += tm->tm_min;
82   res *= 60;
83   res += tm->tm_sec;
84   return res;
85 }
86