#include <alef.h>#include <bio.h>#include "httpd.h" /* * print dates in the format * Wkd, DD Mon YYYY HH:MM:SS GMT * parse dates of formats * Wkd, DD Mon YYYY HH:MM:SS GMT * Weekday, DD-Mon-YY HH:MM:SS GMT * Wkd Mon ( D|DD) HH:MM:SS YYYY * plus anything similar */byte *weekdayname[7] ={	"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};byte *wdayname[7] ={	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"}; byte *monname[12] ={	"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}; intern	int	dateindex(byte*, byte**, int); intern inttolower(int c){	if(c >= 'A' && c <= 'Z')		return c - 'A' + 'a';	return c;} intern intisalpha(int c){	return c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z';} intern intisdig(int c){	return c >= '0' && c <= '9';} intdateconv(Printspec *p){	Tm *tm;	byte buf[128];	int t; 	t = *(int*)p->o;	tm = gmtime(t);	snprint(buf, sizeof(buf), "%s, %.2d %s %.4d %.2d:%.2d:%.2d GMT",		wdayname[tm->wday], tm->mday, monname[tm->mon], tm->year+1900,		tm->hour, tm->min, tm->sec);	strconv(p, buf);	return sizeof(int);} intern byte*dateword(byte *date, byte *buf){	byte *p;	int c; 	p = buf;	while(!isalpha(c = *date) && !isdig(c) && c)		date++;	while(isalpha(c = *date)){		if(p - buf < 30)			*p++ = tolower(c);		date++;	}	*p = 0;	return date;} intern (byte*, int)datenum(byte *date){	int c, n; 	while(!isdig(c = *date) && c)		date++;	if(c == 0)		return (date, -1);	n = 0;	while(isdig(c = *date)){		n = n * 10 + c - '0';		date++;	}	return (date, n);} /* * parse a date and return the seconds since the epoch * return 0 for a failure */uintdate2sec(byte *date){	Tm tm;	byte buf[32]; 	/*	 * Weekday|Wday	 */	date = dateword(date, buf);	tm.wday = dateindex(buf, wdayname, 7);	if(tm.wday < 0)		tm.wday = dateindex(buf, weekdayname, 7);	if(tm.wday < 0)		return 0; 	/*	 * check for the two major formats	 */	date = dateword(date, buf);	tm.mon = dateindex(buf, monname, 12);	if(tm.mon >= 0){		/*		 * MM		 */		(date, tm.mday) = datenum(date);		if(tm.mday < 1 || tm.mday > 31)			return 0; 		/*		 * HH:MM:SS		 */		(date, tm.hour) = datenum(date);		if(tm.hour < 0 || tm.hour >= 24)			return 0;		(date, tm.min) = datenum(date);		if(tm.min < 0 || tm.min >= 60)			return 0;		(date, tm.sec) = datenum(date);		if(tm.sec < 0 || tm.sec >= 60)			return 0; 		/*		 * YYYY		 */		(nil, tm.year) = datenum(date);		if(tm.year < 70 || tm.year > 99 && tm.year < 1970)			return 0;		if(tm.year >= 1970)			tm.year -= 1900;	}else{		/*		 * MM-Mon-(YY|YYYY)		 */		(date, tm.mday) = datenum(date);		if(tm.mday < 1 || tm.mday > 31)			return 0;		date = dateword(date, buf);		tm.mon = dateindex(buf, monname, 12);		if(tm.mon < 0 || tm.mon >= 12)			return 0;		(date, tm.year) = datenum(date);		if(tm.year < 70 || tm.year > 99 && tm.year < 1970)			return 0;		if(tm.year >= 1970)			tm.year -= 1900; 		/*		 * HH:MM:SS		 */		(date, tm.hour) = datenum(date);		if(tm.hour < 0 || tm.hour >= 24)			return 0;		(date, tm.min) = datenum(date);		if(tm.min < 0 || tm.min >= 60)			return 0;		(date, tm.sec) = datenum(date);		if(tm.sec < 0 || tm.sec >= 60)			return 0; 		/*		 * timezone		 */		dateword(date, buf);		if(strncmp(buf, "gmt", 3) != 0)			return 0;	} 	strcpy(tm.zone, "GMT");	return gmtm2sec(tm);} intern intdateindex(byte *d, byte **tab, int n){	byte *s, *t;	int i; 	for(i = 0; i < n; i++){		t = tab[i];		for(s = d; *s && tolower(*s) == tolower(*t); s++)			t++;		if(*s == 0 && *t == 0)			return i;	}	return -1;}