#include <u.h>#include <libc.h>#include <bio.h>#include <regexp.h>#include <ctype.h> typedef struct Date	Date;struct Date {	Reprog *p;	/* an RE to match this date */	Date *next;	/* pointer to next in list */}; enum{	Secondsperday = 24*60*60}; Biobuf in;int debug, matchyear; Date *dates(Date**, Tm*);void upper2lower(char*, char*, int);void *alloc(unsigned int); voidmain(int argc, char *argv[]){	int i, fd;	long now;	char *line;	Tm *tm;	Date *first, *last, *d;	char buf[1024]; 	ARGBEGIN{	case 'y':		matchyear = 1;		break;	case 'd':		debug = 1;		break;	default:		fprint(2, "usage: calendar [-d] [files ...]\n");		exits("usage");	}ARGEND; 	/* make a list of dates */	now = time(0);	tm = localtime(now);	first = dates(&last, tm);	now += Secondsperday;	tm = localtime(now);	dates(&last, tm);	if(tm->wday == 6){		now += Secondsperday;		tm = localtime(now);		dates(&last, tm);	}	if(tm->wday == 0){		now += Secondsperday;		tm = localtime(now);		dates(&last, tm);	} 	for(i=0; i<argc || (i==0 && argc==0); i++){		if(i==0 && argc==0)			snprint(buf, sizeof(buf),				"/usr/%s/lib/calendar", getuser());		else			strcpy(buf, argv[i]);		fd = open(buf, OREAD);		if(fd<0 || Binit(&in, fd, OREAD)<0){			fprint(2, "calendar: can't open %s: %r\n", buf);			exits("open");		} 		/* go through the file */		while(line = Brdline(&in, '\n')){			line[Blinelen(&in) - 1] = 0;			upper2lower(buf, line, sizeof buf);			for(d=first; d; d=d->next)				if(regexec(d->p, buf, 0, 0)){					print("%s\n", line);					break;				}		}		close(fd);	}	exits("");} char *months[] = {	"january",	"february",	"march",	"april",	"may",	"june",	"july",	"august",	"september",	"october",	"november",	"december"}; /* * Generate two Date structures.  First has month followed by day; * second has day followed by month.  Link them into list after * last, and return the first. */Date*dates(Date **last, Tm *tm){	Date *first;	Date *nd;	char mo[128], buf[128]; 	if(utflen(months[tm->mon]) > 3)		snprint(mo, sizeof mo, "%3.3s(%s)?",			months[tm->mon], months[tm->mon]+3);	else		snprint(mo, sizeof mo, "%3.3s", months[tm->mon]);	if (matchyear)		snprint(buf, sizeof buf,			"(^| |\t)((%s( |\t)+)|(%d/))%d( |\t|$)(((%d|%d)( |\t|$))|[^0-9]|([0-9]+[^0-9 \t]))",			mo, tm->mon+1, tm->mday, tm->year+1900, tm->year%100);	else		snprint(buf, sizeof buf,			"(^| |\t)((%s( |\t)+)|(%d/))%d( |\t|$)",			mo, tm->mon+1, tm->mday);	if(debug)		print("%s\n", buf); 	first = alloc(sizeof(Date));	if(*last)		(*last)->next = first;	first->p = regcomp(buf);	 	if (matchyear)		snprint(buf, sizeof buf,			"(^| |\t)%d( |\t)+(%s)( |\t|$)(((%d|%d)( |\t|$))|[^0-9]|([0-9]+[^0-9 \t]))",			tm->mday, mo, tm->year+1900, tm->year%100);	else		snprint(buf, sizeof buf,			"(^| |\t)%d( |\t)+(%s)( |\t|$)",			tm->mday, mo);	if(debug)		print("%s\n", buf);	nd = alloc(sizeof(Date));	nd->p = regcomp(buf);		nd->next = 0;	first->next = nd;	*last = nd; 	return first;} /* * Copy 'from' to 'to', converting to lower case */voidupper2lower(char *to, char *from, int len){	while(--len>0 && *from!='\0')		*to++ = tolower(*from++);	*to = 0;} /* * Call malloc and check for errors */void*alloc(unsigned int n){	void *p; 	p = malloc(n);	if(p == 0){		fprint(2, "calendar: malloc failed: %r\n");		exits("malloc");	}	return p;}