1 /* $OpenBSD: ctime.c,v 1.6 2018/05/23 16:23:48 cheloha Exp $ */ 2 3 /* 4 * Copyright (c) 1998 Michael Shalayeff 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <sys/time.h> 29 #include "stand.h" 30 31 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0) 32 33 char * 34 ctime(const time_t *clock) 35 { 36 static const char wdays[][4] = { 37 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" 38 }; 39 static const char months[][4] = { 40 "Jan", "Feb", "Mar", "Apr", "May", "Jun", 41 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" 42 }; 43 static const u_int monthcnt[] = { 44 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 45 }; 46 static char buf[64]; 47 int ss, mm, hh, wday, month, year; 48 time_t tt = *clock; 49 50 ss = tt % 60; 51 tt /= 60; /* minutes */ 52 mm = tt % 60; 53 tt /= 60; /* hours */ 54 hh = tt % 24; 55 tt /= 24; /* days */ 56 wday = (4 + tt) % 7; /* weekday, 'twas thursday when time started */ 57 58 for (year = 1970; tt >= 365; year++) 59 tt -= isleap(year)? 366: 365; 60 61 tt++; /* days are 1-based */ 62 63 for (month = 0; tt > monthcnt[month]; month++) 64 tt -= monthcnt[month]; 65 66 if (month > 2 && isleap(year)) 67 tt--; 68 69 snprintf(buf, sizeof buf, "%s %s%3d %02d:%02d:%02d %d\n", 70 ((wday < 0 || wday >= 7)? "???": wdays[wday]), 71 ((month < 0 || month >= 12)? "???": months[month]), 72 (int)tt, hh, mm, ss, year); 73 return buf; 74 } 75