ref: d2e6790b3ff30aaa4a3a91e80334548155219d81
dir: /date.c/
#include <u.h>
#include <libc.h>
#include "date.h"
int
str2mon(char *s)
{
if(!strcmp(s, "Jan")) return 0;
if(!strcmp(s, "Feb")) return 1;
if(!strcmp(s, "Mar")) return 2;
if(!strcmp(s, "Apr")) return 3;
if(!strcmp(s, "May")) return 4;
if(!strcmp(s, "Jun")) return 5;
if(!strcmp(s, "Jul")) return 6;
if(!strcmp(s, "Aug")) return 7;
if(!strcmp(s, "Sep")) return 8;
if(!strcmp(s, "Oct")) return 9;
if(!strcmp(s, "Nov")) return 10;
if(!strcmp(s, "Dec")) return 11;
return 0;
}
int
str2wday(char *s)
{
if(!strcmp(s, "Sun")) return 0;
if(!strcmp(s, "Mon")) return 1;
if(!strcmp(s, "Tue")) return 2;
if(!strcmp(s, "Wed")) return 3;
if(!strcmp(s, "Thu")) return 4;
if(!strcmp(s, "Fri")) return 5;
if(!strcmp(s, "Sat")) return 6;
return 0;
}
int
doty(int day, int month, int year)
{
int n, i;
n = 0;
for(i = 0; i < month; i++){
if(i == 0) n += 31;
if(i == 1){
if(year%4 == 0 && year%100 == 0 && year%400 != 0)
n += 29;
else
n += 28;
}
if(i == 2) n += 31;
if(i == 3) n += 30;
if(i == 4) n += 31;
if(i == 5) n += 30;
if(i == 6) n += 31;
if(i == 7) n += 31;
if(i == 8) n += 30;
if(i == 9) n += 31;
if(i == 10) n += 30;
if(i == 11) n += 31;
}
n += day;
return n;
}
long
parseatomdate(char *input)
{
/* YYYY-MM-DDTHH:MM:SSZ */
/* YYYY year */
/* MM month */
/* DD day of month */
/* T or space */
/* HH hour */
/* MM minute */
/* SS seconds */
/* .SS seconds (sub, optional) */
/* Z zulu (UTC+0) */
/* +HH:MM tz offset */
/* examples: length */
/* 2020-06-05( |T)13:20:35.44+04:00 28 */
/* 2020-06-05( |T)13:20:35+04:00 25 */
/* 2020-06-05( |T)13:20:35.44Z 23 */
/* 2020-06-05( |T)13:20:35Z 20 */
Tm ret;
char *args[9];
char s[32];
int n;
strcpy(s, input);
switch(strlen(s)){
case 28:
n = getfields(s, args, 9, 1, "- T:.+Z");
if(n != 9)
sysfatal("error parsing atom date: %d", n);
ret.year = atoi(args[0]) - 1900;
ret.mon = atoi(args[1]) - 1;
ret.mday = atoi(args[2]);
ret.tzoff = atoi(args[7]);
ret.hour = atoi(args[3]);
ret.min = atoi(args[4]);
ret.sec = atoi(args[5]);
break;
case 25:
n = getfields(s, args, 8, 1, "- T:.+Z");
if(n != 8)
sysfatal("error parsing atom date: %d", n);
ret.year = atoi(args[0]) - 1900;
ret.mon = atoi(args[1]) - 1;
ret.mday = atoi(args[2]);
ret.tzoff = atoi(args[6]);
ret.hour = atoi(args[3]);
ret.min = atoi(args[4]);
ret.sec = atoi(args[5]);
break;
case 23:
n = getfields(s, args, 7, 1, "- T:.+Z");
if(n != 7)
sysfatal("error parsing atom date: %d", n);
ret.year = atoi(args[0]) - 1900;
ret.mon = atoi(args[1]);
ret.mday = atoi(args[2]);
ret.tzoff = 0;
ret.hour = atoi(args[3]);
ret.min = atoi(args[4]);
ret.sec = atoi(args[5]);
break;
case 20:
n = getfields(s, args, 6, 1, "- T:.+Z");
if(n != 6)
sysfatal("error parsing atom date: %d", n);
ret.year = atoi(args[0]) - 1900;
ret.mon = atoi(args[1]) - 1;
ret.mday = atoi(args[2]);
ret.tzoff = 0;
ret.hour = atoi(args[3]);
ret.min = atoi(args[4]);
ret.sec = atoi(args[5]);
break;
default:
sysfatal("error parsing atom date format: %s", s);
}
ret.yday = doty(ret.mday, ret.mon, ret.year);
return tm2sec(&ret) - ret.tzoff*60*60;
}
long
parsedate(char *s)
{
Tm ret;
char input[64];
char *args[8];
int n, i;
strcpy(input, s);
n = getfields(input, args, 8, 1, ", :");
if(n < 8){
/* try parsing atom date */
return parseatomdate(s);
}
for(i = 0; i < n; i++){
if(!args[i])
sysfatal("error parsing pubDate: %s", s);
switch(i){
case 0: /* day of the week */
ret.wday = str2wday(args[i]);
break;
case 1: /* day of the month */
ret.mday = atoi(args[i]);
break;
case 2: /* month of the year */
ret.mon = str2mon(args[i]);
break;
case 3: /* year */
ret.year = atoi(args[i]) - 1900;
break;
case 4: /* hour */
ret.hour = atoi(args[i]);
break;
case 5: /* minute */
ret.min = atoi(args[i]);
break;
case 6: /* second */
ret.sec = atoi(args[i]);
break;
case 7: /* timezone offset */
ret.tzoff = atoi(args[i])/100;
break;
}
}
ret.yday = doty(ret.mday, ret.mon, ret.year);
return tm2sec(&ret) - ret.tzoff*60*60;
}