freebsd-nq/bin/date/vary.c
1997-12-21 12:11:13 +00:00

413 lines
8.9 KiB
C

/*-
* Copyright (c) 1997 Brian Somers <brian@Awfulhak.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
*/
#include <time.h>
#include <string.h>
#include <stdlib.h>
#include "vary.h"
struct trans {
int val;
char *str;
};
static struct trans trans_mon[] = {
{ 1, "january" }, { 2, "february" }, { 3, "march" }, { 4, "april" },
{ 6, "june" }, { 7, "july" }, { 8, "august" }, { 9, "september" },
{ 10, "october" }, { 11, "november" }, { 12, "december" },
{ -1, NULL }
};
static struct trans trans_wday[] = {
{ 0, "sunday" }, { 1, "monday" }, { 2, "tuesday" }, { 3, "wednesday" },
{ 4, "thursday" }, { 5, "friday" }, { 6, "saturday" },
{ -1, NULL }
};
static char digits[] = "0123456789";
static int
trans(const struct trans t[], const char *arg)
{
int f;
for (f = 0; t[f].val != -1; f++)
if (!strncasecmp(t[f].str, arg, 3) ||
!strncasecmp(t[f].str, arg, strlen(t[f].str)))
return t[f].val;
return -1;
}
struct vary *
vary_append(struct vary *v, char *arg)
{
struct vary *result, **nextp;
if (v) {
result = v;
while (v->next)
v = v->next;
nextp = &v->next;
} else
nextp = &result;
*nextp = (struct vary *)malloc(sizeof(struct vary));
(*nextp)->arg = arg;
(*nextp)->next = NULL;
return result;
}
static int mdays[12] = { 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
static int
daysinmonth(const struct tm *t)
{
int year;
year = t->tm_year + 1900;
if (t->tm_mon == 1)
if (!(year % 400))
return 29;
else if (!(year % 100))
return 28;
else if (!(year % 4))
return 29;
else
return 28;
else if (t->tm_mon >= 0 && t->tm_mon < 12)
return mdays[t->tm_mon];
return 0;
}
static int
adjyear(struct tm *t, char type, int val)
{
switch (type) {
case '+':
t->tm_year += val;
break;
case '-':
t->tm_year -= val;
break;
default:
t->tm_year = val;
if (t->tm_year < 69)
t->tm_year += 100; /* as per date.c */
else if (t->tm_year > 1900)
t->tm_year -= 1900; /* struct tm holds years since 1900 */
break;
}
return mktime(t) != -1;
}
static int
adjmon(struct tm *t, char type, int val, int istext)
{
if (val < 0)
return 0;
switch (type) {
case '+':
if (istext)
if (val <= t->tm_mon)
val += 11 - t->tm_mon; /* early next year */
else
val -= t->tm_mon + 1; /* later this year */
if (!adjyear(t, '+', (t->tm_mon + val) / 12))
return 0;
val %= 12;
t->tm_mon += val;
if (t->tm_mon > 11)
t->tm_mon -= 12;
break;
case '-':
if (istext)
if (val-1 > t->tm_mon)
val = 13 - val + t->tm_mon; /* later last year */
else
val = t->tm_mon - val + 1; /* early this year */
if (!adjyear(t, '-', val / 12))
return 0;
val %= 12;
if (val > t->tm_mon) {
if (!adjyear(t, '-', 1))
return 0;
val -= 12;
}
t->tm_mon -= val;
break;
default:
if (val > 12 || val < 1)
return 0;
t->tm_mon = --val;
}
return mktime(t) != -1;
}
static int
adjday(struct tm *t, char type, int val)
{
int mdays;
switch (type) {
case '+':
while (val) {
mdays = daysinmonth(t);
if (val > mdays - t->tm_mday) {
val -= mdays - t->tm_mday + 1;
t->tm_mday = 1;
if (!adjmon(t, '+', 1, 0))
return 0;
} else {
t->tm_mday += val;
val = 0;
}
}
break;
case '-':
while (val)
if (val >= t->tm_mday) {
val -= t->tm_mday;
t->tm_mday = 1;
if (!adjmon(t, '-', 1, 0))
return 0;
t->tm_mday = daysinmonth(t);
} else {
t->tm_mday -= val;
val = 0;
}
break;
default:
if (val > 0 && val <= daysinmonth(t))
t->tm_mday = val;
else
return 0;
break;
}
return mktime(t) != -1;
}
static int
adjwday(struct tm *t, char type, int val, int istext)
{
if (val < 0)
return 0;
switch (type) {
case '+':
if (istext)
if (val < t->tm_wday)
val = 7 - t->tm_wday + val; /* early next week */
else
val -= t->tm_wday; /* later this week */
else
val *= 7; /* "-W +5" == "5 weeks in the future" */
return adjday(t, '+', val);
case '-':
if (istext)
if (val > t->tm_wday)
val = 7 - val + t->tm_wday; /* later last week */
else
val = t->tm_wday - val; /* early this week */
else
val *= 7; /* "-W -5" == "5 weeks ago" */
return adjday(t, '-', val);
default:
if (val < t->tm_wday)
return adjday(t, '-', t->tm_wday - val);
else if (val > 6)
return 0;
else if (val > t->tm_wday)
return adjday(t, '+', val - t->tm_wday);
}
return 1;
}
static int
adjhour(struct tm *t, char type, int val)
{
if (val < 0)
return 0;
switch (type) {
case '+':
if (!adjday(t, '+', (t->tm_hour + val) / 24))
return 0;
val %= 24;
t->tm_hour += val;
if (t->tm_hour > 23)
t->tm_hour -= 24;
break;
case '-':
if (!adjday(t, '-', val / 24))
return 0;
val %= 24;
if (val > t->tm_hour) {
if (!adjday(t, '-', 1))
return 0;
val -= 24;
}
t->tm_hour -= val;
break;
default:
if (val > 23)
return 0;
t->tm_hour = val;
}
return mktime(t) != -1;
}
static int
adjmin(struct tm *t, char type, int val)
{
if (val < 0)
return 0;
switch (type) {
case '+':
if (!adjhour(t, '+', (t->tm_min + val) / 60))
return 0;
val %= 60;
t->tm_min += val;
if (t->tm_min > 59)
t->tm_min -= 60;
break;
case '-':
if (!adjhour(t, '-', val / 60))
return 0;
val %= 60;
if (val > t->tm_min) {
if (!adjhour(t, '-', 1))
return 0;
val -= 60;
}
t->tm_min -= val;
break;
default:
if (val > 59)
return 0;
t->tm_min = val;
}
return mktime(t) != -1;
}
const struct vary *
vary_apply(const struct vary *v, struct tm *t)
{
char type;
char which;
char *arg;
int len;
int val;
for (; v; v = v->next) {
type = *v->arg;
arg = v->arg;
if (type == '+' || type == '-')
arg++;
else
type = '\0';
len = strlen(arg);
if (len < 2)
return v;
if (strspn(arg, digits) != len-1) {
val = trans(trans_wday, arg);
if (val != -1) {
if (!adjwday(t, type, val, 1))
return v;
} else {
val = trans(trans_mon, arg);
if (val != -1) {
if (!adjmon(t, type, val, 1))
return v;
} else
return v;
}
} else {
val = atoi(arg);
which = arg[len-1];
switch (which) {
case 'M':
if (!adjmin(t, type, val))
return v;
break;
case 'H':
if (!adjhour(t, type, val))
return v;
break;
case 'd':
if (!adjday(t, type, val))
return v;
break;
case 'w':
if (!adjwday(t, type, val, 0))
return v;
break;
case 'm':
if (!adjmon(t, type, val, 0))
return v;
break;
case 'y':
if (!adjyear(t, type, val))
return v;
break;
default:
return v;
}
}
}
return 0;
}
void
vary_destroy(struct vary *v)
{
struct vary *n;
while (v) {
n = v->next;
free(v);
v = n;
}
}