4.1cBSD/usr/src/usr.lib/undoc/libpriv/asctotime.c
/* @(#)asctotime.c 4.2 (Melbourne) 82/02/15 */
/*
* Asctotime by Mark Davoren (plus emitl and dcmp from unctime.c)
*
* Routines to take a date string and return the number of seconds
* since the epoch to 0:00 am that day (local time)
* There are 10 allowable formats
* 1 d
* 2 d m
* 3 d m y
* 4 d M y
* 5 d M
* 6 D
* 7 M d
* 8 M d y
* 9 y m d
* 10 y M d
* where d, m and y represent day, month and year respectively.
* small letters mean a number, capitals mean a name.
* With the year either 19xx or xx is allowable.
* Times beyond the end of the 20th century are not handled.
*
* Any of the formats may include a time specification in the
* form hh:mm[:ss]
*
* With format 6;
* D : today <= D < today next week
* An optional '-' may directly precede the day name
* -D : today last week <= D < today
* This may also be suffixed by one of "week" or "fortnight"
*
* Most sensible abbreviations are allowable for day and month names,
* names can be of either upper, lower or mixed case.
* Formats 1-5 may have an optional 'st', 'nd', 'rd', 'th' after the day
* if the day is the first, second, third or later day of the month
* respectively.
* asctotime knows about leap years
*/
#include <time.h>
#include <sys/types.h>
#include <ctype.h>
#include <stdio.h>
#define bufmax 20
#define error(s) { a2terr = s; return(-1); }
char *a2terr;
struct tm *localtime();
time_t time();
time_t emitl();
char *index();
/*
* Structures for days and months.
*/
struct daynum {
char *name;
int num;
};
static struct daynum months[] = {
"jan_uary", 31,
"feb_ruary", 29,
"mar_ch", 31,
"apr_il", 30,
"may", 31,
"jun_e", 30,
"jul_y", 31,
"aug_ust", 31,
"sep_t_ember", 30,
"oct_ober", 31,
"nov_ember", 30,
"dec_ember", 31,
(char *)0
}, days[] = {
"su_n_day", 0,
"mo_n_day", 1,
"tu_e_s_day", 2,
"we_d_nesday", 3,
"th_u_r_s_day", 4,
"fr_i_day", 5,
"sa_t_urday", 6,
"today", 7,
"tomorrow", 8,
"yesterday", 9,
(char *)0
};
/*
* Getday is the main routine, which decodes the date string.
* It checks the values of each field and fills in default fields
*/
time_t
asctotime(p, ww)
char *p;
struct tm *ww;
{
register struct tm *w, *t;
register int i, mflag = 0, flag678 = 0;
int x;
struct tm tm;
char buff[bufmax];
char copy[256];
register char *q;
char *s;
strncpy(copy, p, sizeof copy - 1);
copy[sizeof copy - 1] = 0;
for (q = copy; *q; q++)
if (isupper(*q))
*q = tolower(*q);
p = copy;
a2terr = (char *)0;
if (ww)
w = ww;
else
w = &tm;
x = time((time_t *)0);
t = localtime(&x);
scan(&p);
if (*p == '\0')
return(emitl(t));
w->tm_sec = w->tm_min = w->tm_hour = 0;
if (q = index(p, ':')) { /* a time is specified */
while (isspace(*--q) && q > p)
;
while (isdigit(*q) && q >= p)
q--;
while (q >= p && isspace(*q))
q--;
q++;
s = q;
w->tm_hour = getnum(&s);
s = index(s, ':')+1; /* ':' must exist */
w->tm_min = getnum(&s);
if (index(s, ':')) { /* have seconds */
s = index(s, ':')+1;
w->tm_sec = getnum(&s);
}
scan(&s);
if (s[1] == 'm') {
if (s[0] == 'p')
w->tm_hour += 12;
else if (s[0] != 'a')
s-= 2;
else if (w->tm_hour == 12)
w->tm_hour = 0;
s += 2;
}
if (w->tm_hour == 24) {
if (s[-2] == 'p')
w->tm_hour = 12;
else
w->tm_hour = 0;
}
if (w->tm_hour > 23 || w->tm_min > 59 || w->tm_sec > 59)
error("bad time");
/* now remove the time from the buffer */
*q++ = ' ';
while (*q++ = *s++)
;
scan(&p);
if (*p == '\0') {
strcpy(copy, "today");
p = copy;
}
}
if (strncmp(p, "last", 4) == 0) {
mflag++;
p += 4;
scan(&p);
} else if (strncmp(p, "next", 4) == 0) {
mflag--;
p += 4;
scan(&p);
} else if (*(p-1) == '-')
mflag++;
/* if there is a word here put it into buff */
if (isalpha(*p)) {
for (q = buff; isalpha(*p) && q < &buff[bufmax-1]; )
*q++ = *p++;
*q = '\0';
scan(&p);
flag678++;
}
if (isdigit(*p)) { /* Formats 1-5, 7, 8 */
w->tm_mday = getnum(&p);
getends(w->tm_mday, &p);
if (w->tm_mday > 31) { /* must be a year instead */
w->tm_year = w->tm_mday;
w->tm_mday = 0;
}
if (flag678) { /* Formats 7 or 8 */
if ((w->tm_mon = getname(months, buff) + 1) == 0)
error("Bad month name");
} else if (isalpha(*p)) { /* Formats 4, 5 */
for (q = buff; isalpha(*p) && q < &buff[bufmax-1]; )
*q++ = *p++;
*q = '\0';
if ((w->tm_mon = getname(months, buff) + 1) == 0)
error("Bad month name");
} else { /* Formats 1-3 */
w->tm_mon = getnum(&p);
getends(w->tm_mon, &p);
}
/* check for format 1 */
if (w->tm_mon == 0)
w->tm_mon = t->tm_mon;
else
w->tm_mon--;
/* get year */
scan(&p);
if (w->tm_mday == 0)
getends(w->tm_mday = getnum(&p), &p);
else
getends(w->tm_year = getnum(&p), &p);
/* validate month */
if (w->tm_mon > 11)
error("month field too large");
/* validate day */
if (w->tm_mday == 0 || w->tm_mday > months[w->tm_mon].num)
error("day field too large");
/* check for formats 1,2 and 5 */
if (w->tm_year == 0) {
w->tm_year = t->tm_year;
if (w->tm_mon + 8 < t->tm_mon && mflag <= 0)
w->tm_year++;
}
/* check for 29th of feb in a non leap year */
if ( w->tm_mon == 1
&& w->tm_mday == 29
&& !( w->tm_year % 4 == 0
&& w->tm_year % 100 != 0
|| w->tm_year % 400 == 0))
error("not a leap year");
if (w->tm_year >= 1970)
w->tm_year -= 1900;
else if (w->tm_year > 100 || w->tm_year < 70)
error("year field too small");
} else { /* format 6 */
i = getname(days, buff);
if (i == -1)
error("error in day name");
/* check for today & tomorrow & yesterday */
if (i == 7) {
i = t->tm_wday;
mflag = 0;
} else if (i == 8) {
i = t->tm_wday+1 % 7;
mflag = -1;
} else if (i == 9) {
i = t->tm_wday+6 % 7;
mflag = 1;
}
w->tm_year = t->tm_year;
w->tm_mon = t->tm_mon;
w->tm_mday = t->tm_mday - (t->tm_wday - i);
if (mflag > 0 && t->tm_wday <= i)
w->tm_mday -= 7;
if (mflag == 0 && t->tm_wday > i)
w->tm_mday += 7;
if (mflag < 0 && t->tm_wday == i)
w->tm_mday += 7;
scan(&p);
if (strcmp(p, "week") == 0)
i = 7;
else if (strcmp(p, "fortnight") == 0)
i = 14;
else
i = 0;
if (mflag > 0)
w->tm_mday -= i;
else
w->tm_mday += i;
/* allow for wrap around */
if (w->tm_mday < 1) {
/* last month */
w->tm_mon--;
w->tm_mday += months[w->tm_mon].num;
if (w->tm_mon < 0) {
/* last year */
w->tm_year--;
w->tm_mon = 11;
}
} else if (w->tm_mday > months [w->tm_mon].num) {
/* next month */
w->tm_mday -= months[w->tm_mon].num;
w->tm_mon++;
if (w->tm_mon > 11) {
/* next year */
w->tm_year++;
w->tm_mon = 0;
}
}
}
return(emitl(w));
}
static
scan(pp)
register char **pp;
{
while(**pp && !isalpha(**pp) && !isdigit(**pp))
++*pp;
}
static
getends(i, pp)
register int i;
char **pp;
{
register char *p;
register c0, c1;
p = *pp;
c0 = p[0];
if (c0 == '\0')
return;
c1 = p[1];
switch (i % 10) {
case 1:
if (c0 == 's' && c1 == 't')
p += 2;
break;
case 2:
if (c0 == 'n' && c1 == 'd')
p += 2;
break;
case 3:
if (c0 == 'r' && c1 == 'd')
p += 2;
break;
default:
if (c0 == 't' && c1 == 'h')
p += 2;
break;
}
*pp = p;
scan(pp);
}
static
getnum(q)
char **q;
{
register int sum;
register char *p;
p = *q;
while (*p && !isdigit(*p))
p++;
sum = 0;
while (isdigit(*p))
sum = sum * 10 + *p++ - '0';
*q = p;
return(sum);
}
/*
* Getname searches arr an array of daynum structures for a name matching
* the name passed as an argument. The entries in the array consist
* of words with '_' delimiting abbreviations;
* eg 'mon_day' will match 'mon' or 'monday'
* Getname returns the index into arr which matches name or -1 if no match
*/
static
getname(arr, name)
struct daynum arr[];
register char *name;
{
register struct daynum *i;
register char *p, *q;
for(i = arr; i->name; i++) {
for (p = name, q = i->name; *p; p++, q++) {
if (*p == *q)
continue;
if (*q != '_')
break;
p--;
}
if (*p == '\0' && (*q == '\0' || *q == '_'))
return(i - arr);
}
return(-1);
}
/*
* Routine to convert a localtime(3) format date back into
* a system format date.
*
* Use a binary search.
*/
time_t
emitl(dp)
struct tm *dp;
{
time_t conv;
register int i, bit;
struct tm dcopy;
dcopy = *dp;
dp = &dcopy;
conv = 0;
for (i = 30; i >= 0; i--) {
bit = 1 << i;
conv |= bit;
if (dcmp(localtime(&conv), dp) > 0)
conv &= ~bit;
}
return(conv);
};
/*
* Compare two localtime dates, return result.
*/
#define DECIDE(a) \
if (dp->a > dp2->a) \
return(1); \
if (dp->a < dp2->a) \
return(-1)
static
dcmp(dp, dp2)
register struct tm *dp, *dp2;
{
DECIDE(tm_year);
DECIDE(tm_mon);
DECIDE(tm_mday);
DECIDE(tm_hour);
DECIDE(tm_min);
DECIDE(tm_sec);
return(0);
}