56 static date	*date2idt(date *idt, date *dt);
57 static date	*idt2date(date *dt, date *idt);
58 static int	 ndaysji(date *idt);
59 static int	 ndaysgi(date *idt);
69 	date    idt;		/* Internal date representation */  in jdate()  local
77 	idt.y = ndays / 365;  in jdate()
78 	idt.m = 0;  in jdate()
79 	idt.d = 0;  in jdate()
80 	while ((r = ndaysji(&idt)) > ndays)  in jdate()
81 		idt.y--;  in jdate()
89 	for (idt.m = 11; month1[idt.m] > r; idt.m--)  in jdate()
93 	idt.d = r - month1[idt.m];  in jdate()
96 	return (idt2date(dt, &idt));  in jdate()
106 	date    idt;		/* Internal date representation */  in ndaysj()  local
108 	if (date2idt(&idt, dt) == NULL)  in ndaysj()
111 		return (ndaysji(&idt));  in ndaysj()
119 ndaysji(date * idt)  in ndaysji()  argument
122 	return (idt->d + month1[idt->m] + idt->y * 365 + idt->y / 4);  in ndaysji()
134 	date    idt;		/* for internal date representation */  in gdate()  local
142 	idt.y = ndays / 365;  in gdate()
143 	idt.m = 0;  in gdate()
144 	idt.d = 0;  in gdate()
145 	while ((r = ndaysgi(&idt)) > ndays)  in gdate()
146 		idt.y--;  in gdate()
159 	if (idt.y == 1582)  in gdate()
164 	for (idt.m = 11; montht[idt.m] > ndays; idt.m--)  in gdate()
167 	idt.d = ndays - montht[idt.m]; /* the rest is the day in month */  in gdate()
170 	if (idt.y == jiswitch.y && idt.m == jiswitch.m && jiswitch.d < idt.d)  in gdate()
171 		idt.d += 10;  in gdate()
174 	return (idt2date(dt, &idt));  in gdate()
185 	date    idt;		/* Internal date representation */  in ndaysg()  local
187 	if (date2idt(&idt, dt) == NULL)  in ndaysg()
189 	return (ndaysgi(&idt));  in ndaysg()
197 ndaysgi(date *idt)  in ndaysgi()  argument
218 	if ((nd = ndaysji(idt)) == -1)  in ndaysgi()
220 	if (idt->y >= 1600)  in ndaysgi()
221 		nd = (nd - 10 - (idt->y - 1600) / 100 + (idt->y - 1600) / 400);  in ndaysgi()
251 	date idt;  in firstweek()  local
254 	idt.y = y - 1;   /* internal representation of y-1-1 */  in firstweek()
255 	idt.m = 10;  in firstweek()
256 	idt.d = 0;  in firstweek()
258 	nd = ndaysgi(&idt);  in firstweek()
296 date2idt(date *idt, date *dt)  in date2idt()  argument
299 	idt->d = dt->d - 1;  in date2idt()
301 		idt->m = dt->m - 3;  in date2idt()
302 		idt->y = dt->y;  in date2idt()
304 		idt->m = dt->m + 9;  in date2idt()
305 		idt->y = dt->y - 1;  in date2idt()
307 	if (idt->m < 0 || idt->m > 11 || idt->y < 0)  in date2idt()
310 		return idt;  in date2idt()
315 idt2date(date *dt, date *idt)  in idt2date()  argument
318 	dt->d = idt->d + 1;  in idt2date()
319 	if (idt->m < 10) {  in idt2date()
320 		dt->m = idt->m + 3;  in idt2date()
321 		dt->y = idt->y;  in idt2date()
323 		dt->m = idt->m - 9;  in idt2date()
324 		dt->y = idt->y + 1;  in idt2date()