1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
4  * Copyright (c) 2006 Poul-Henning Kamp
7  * Redistribution and use in source and binary forms, with or without
12  * 2. Redistributions in binary form must reproduce the above copyright
28  * Convert MS-DOS FAT format timestamps to and from unix timespecs
33  *	yyyyyyymmmmddddd (year - 1980, month, day)
54  * The conversion functions below cut time into four-year leap-year
64  * they can represent up to 2107 which means that the non-leap-year
80 #define LYC	(4 * YEAR + 1)	/* Length of 4 year leap-year cycle */
98 /* Table of months in a 4 year leap-year cycle */
104 	uint16_t	coded;	/* encoded year + month information */  member
144 	t1 = tsp->tv_sec;  in timespec2fattime()
146 		t1 -= utc_offset();  in timespec2fattime()
149 		*dhp = (tsp->tv_sec & 1) * 100 + tsp->tv_nsec / 10000000;  in timespec2fattime()
158 			/* Impossible date, truncate to 1980-01-01 */  in timespec2fattime()
161 			t2 -= T1980;  in timespec2fattime()
164 			if (t2 >= ((2100 - 1980) / 4 * LYC + FEB))  in timespec2fattime()
170 			t2 -= l * LYC;  in timespec2fattime()
180 			*ddp += mtab[m].coded;  in timespec2fattime()
183 			t2 -= mtab[m].days - 1;  in timespec2fattime()
192  * leap-year cycle
222 	tsp->tv_sec = (dt & 0x1f) << 1;  in fattime2timespec()
223 	tsp->tv_sec += ((dt & 0x7e0) >> 5) * 60;  in fattime2timespec()
224 	tsp->tv_sec += ((dt & 0xf800) >> 11) * 3600;  in fattime2timespec()
225 	tsp->tv_sec += dh / 100;  in fattime2timespec()
226 	tsp->tv_nsec = (dh % 100) * 10000000;  in fattime2timespec()
229 	day = (dd & 0x1f) - 1;  in fattime2timespec()
231 	/* Full leap-year cycles */  in fattime2timespec()
234 	/* Month offset from leap-year cycle */  in fattime2timespec()
238 	if (day >= ((2100 - 1980) / 4 * LYC + FEB))  in fattime2timespec()
239 		day--;  in fattime2timespec()
244 	tsp->tv_sec += (time_t) DAY * day;  in fattime2timespec()
246 		tsp->tv_sec += utc_offset();  in fattime2timespec()
269 			 * 32-bits gets us to 2106-02-07 06:28:15, but we  in main()
271 			 * a 36-bit second count to get us way past 2106.  in main()
278 		printf("%10jd.%03ld -- ", (intmax_t) ts.tv_sec, ts.tv_nsec / 1000000);  in main()
282 		printf("%s -- ", buf);  in main()
284 		a = ts.tv_sec + ts.tv_nsec * 1e-9;  in main()
287 		printf("%04x %04x %02x -- ", d, t, p);  in main()
288 		printf("%3d %02d %02d %02d %02d %02d -- ",  in main()
301 		printf("%s -- ", buf);  in main()
302 		a -= ts.tv_sec + ts.tv_nsec * 1e-9;  in main()