utils.c

/*
 * Copyright (C) 2008, OGAWA Hirofumi
 * Released under GPL v2.
 */

#include "exfat.h"

extern struct timezone sys_tz;

#define C_32(s, p)	do {						\
	C(s, (p)[ 0]); C(s, (p)[ 1]); C(s, (p)[ 2]); C(s, (p)[ 3]);	\
	C(s, (p)[ 4]); C(s, (p)[ 5]); C(s, (p)[ 6]); C(s, (p)[ 7]);	\
	C(s, (p)[ 8]); C(s, (p)[ 9]); C(s, (p)[10]); C(s, (p)[11]);	\
	C(s, (p)[12]); C(s, (p)[13]); C(s, (p)[14]); C(s, (p)[15]);	\
	C(s, (p)[16]); C(s, (p)[17]); C(s, (p)[18]); C(s, (p)[19]);	\
	C(s, (p)[20]); C(s, (p)[21]); C(s, (p)[22]); C(s, (p)[23]);	\
	C(s, (p)[24]); C(s, (p)[25]); C(s, (p)[26]); C(s, (p)[27]);	\
	C(s, (p)[28]); C(s, (p)[29]); C(s, (p)[30]); C(s, (p)[31]);	\
} while (0)

u32 exfat_checksum32(u32 sum, const void *__buf, int size)
{
#define C(s, v)		do { s = __exfat_checksum32(s, v); } while (0)
	const u8 *buf = __buf;
	int i;

	for (i = 0; (i + 511) < size; i += 512) {
		C_32(sum, &buf[i + 32 *  0]); C_32(sum, &buf[i + 32 *  1]);
		C_32(sum, &buf[i + 32 *  2]); C_32(sum, &buf[i + 32 *  3]);
		C_32(sum, &buf[i + 32 *  4]); C_32(sum, &buf[i + 32 *  5]);
		C_32(sum, &buf[i + 32 *  6]); C_32(sum, &buf[i + 32 *  7]);
		C_32(sum, &buf[i + 32 *  8]); C_32(sum, &buf[i + 32 *  9]);
		C_32(sum, &buf[i + 32 * 10]); C_32(sum, &buf[i + 32 * 11]);
		C_32(sum, &buf[i + 32 * 12]); C_32(sum, &buf[i + 32 * 13]);
		C_32(sum, &buf[i + 32 * 14]); C_32(sum, &buf[i + 32 * 15]);
	}
	for (; (i + 31) < size; i += 32)
		C_32(sum, &buf[i]);
	for (; i < size; i++)
		C(sum, buf[i]);

	return sum;
#undef C
}

u16 exfat_checksum16(u16 sum, const void *__buf, int size)
{
#define C(s, v)		do { s = __exfat_checksum16(s, v); } while (0)
	const u8 *buf = __buf;
	int i;

	for (i = 0; (i + 31) < size; i += 32)
		C_32(sum, &buf[i]);
	for (; i < size; i++)
		C(sum, buf[i]);

	return sum;
#undef C
}

int exfat_conv_u2c(struct nls_table *nls,
		   const __le16 **uni, unsigned int *uni_left,
		   unsigned char **out, unsigned int *out_left)
{
	wchar_t wc;
	int len;

	while (*uni_left) {
		wc = le16_to_cpu(**uni);
		if (!wc)
			return -EINVAL;

		len = nls->uni2char(wc, *out, *out_left);
		if (len < 0)
			return len;

		(*uni)++;
		(*uni_left)--;
		*out += len;
		*out_left -= len;
	}

	return 0;
}

int exfat_conv_c2u(struct nls_table *nls,
		   const unsigned char **in, unsigned int *in_left,
		   wchar_t **uni, unsigned int *uni_left)
{
	int len;

	while (*in_left) {
		if (!*uni_left)
			return -ENAMETOOLONG;

		len = nls->char2uni(*in, *in_left, *uni);
		if (len < 0)
			return len;

		*in += len;
		*in_left -= len;
		(*uni)++;
		(*uni_left)--;
	}

	return 0;
}

/*
 * The epoch of exFAT timestamp is 1980.
 *     :  bits :     value
 * date:  0 -  4: day	(1 -  31)
 * date:  5 -  8: month	(1 -  12)
 * date:  9 - 15: year	(0 - 127) from 1980
 * time:  0 -  4: sec	(0 -  29) 2sec counts
 * time:  5 - 10: min	(0 -  59)
 * time: 11 - 15: hour	(0 -  23)
 */
#define SECS_PER_MIN	60
#define SECS_PER_HOUR	(60 * 60)
#define SECS_PER_DAY	(SECS_PER_HOUR * 24)
#define UNIX_SECS_1980	315532800L
#if BITS_PER_LONG == 64
#define UNIX_SECS_2108	4354819200L
#endif
/* days between 1.1.70 and 1.1.80 (2 leap days) */
#define DAYS_DELTA	(365 * 10 + 2)
/* 120 (2100 - 1980) isn't leap year */
#define YEAR_2100	120
#define IS_LEAP_YEAR(y)	(!((y) & 3) && (y) != YEAR_2100)

/* Linear day numbers of the respective 1sts in non-leap years. */
static time_t days_in_year[] = {
	/* Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec */
	0,   0,  31,  59,  90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
};

/* Convert a exFAT time/date pair to a UNIX date (seconds since 1 1 70). */
void exfat_time_exfat2unix(struct timespec *ts, __le16 __time, __le16 __date,
			   u8 time_cs)
{
	u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
	time_t second, day, leap_day, month, year;

	year  = date >> 9;
	month = max(1, (date >> 5) & 0xf);
	day   = max(1, date & 0x1f) - 1;

	leap_day = (year + 3) / 4;
	if (year > YEAR_2100)		/* 2100 isn't leap year */
		leap_day--;
	if (IS_LEAP_YEAR(year) && month > 2)
		leap_day++;

	second =  (time & 0x1f) << 1;
	second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
	second += (time >> 11) * SECS_PER_HOUR;
	second += (year * 365 + leap_day
		   + days_in_year[month] + day
		   + DAYS_DELTA) * SECS_PER_DAY;

	second += sys_tz.tz_minuteswest * SECS_PER_MIN;

	if (time_cs) {
		ts->tv_sec = second + (time_cs / 100);
		ts->tv_nsec = (time_cs % 100) * 10000000;
	} else {
		ts->tv_sec = second;
		ts->tv_nsec = 0;
	}
}

/* Convert linear UNIX date to a exFAT time/date pair. */
void exfat_time_unix2exfat(struct timespec *ts, __le16 *time, __le16 *date,
			   u8 *time_cs)
{
	time_t second = ts->tv_sec;
	time_t day, leap_day, month, year;

	second -= sys_tz.tz_minuteswest * SECS_PER_MIN;

	/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
	if (second < UNIX_SECS_1980) {
		*time = 0;
		*date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
		if (time_cs)
			*time_cs = 0;
		return;
	}
#if BITS_PER_LONG == 64
	if (second >= UNIX_SECS_2108) {
		*time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
		*date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
		if (time_cs)
			*time_cs = 199;
		return;
	}
#endif

	day = second / SECS_PER_DAY - DAYS_DELTA;
	year = day / 365;
	leap_day = (year + 3) / 4;
	if (year > YEAR_2100)		/* 2100 isn't leap year */
		leap_day--;
	if (year * 365 + leap_day > day)
		year--;
	leap_day = (year + 3) / 4;
	if (year > YEAR_2100)		/* 2100 isn't leap year */
		leap_day--;
	day -= year * 365 + leap_day;

	if (IS_LEAP_YEAR(year) && day == days_in_year[3]) {
		month = 2;
	} else {
		if (IS_LEAP_YEAR(year) && day > days_in_year[3])
			day--;
		for (month = 1; month < 12; month++) {
			if (days_in_year[month + 1] > day)
				break;
		}
	}
	day -= days_in_year[month];

	*time = cpu_to_le16(((second / SECS_PER_HOUR) % 24) << 11
			    | ((second / SECS_PER_MIN) % 60) << 5
			    | (second % SECS_PER_MIN) >> 1);
	*date = cpu_to_le16((year << 9) | (month << 5) | (day + 1));
	if (time_cs)
		*time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
}

void exfat_fs_panic(struct super_block *sb, const char *fmt, ...)
{
	va_list args;

	printk(KERN_ERR "exFAT: Filesystem panic (dev %s)\n", sb->s_id);

	printk(KERN_ERR "       ");
	va_start(args, fmt);
	vprintk(fmt, args);
	va_end(args);
	printk("\n");

	if (!(sb->s_flags & MS_RDONLY)) {
		sb->s_flags |= MS_RDONLY;
		printk(KERN_ERR "       File system has been set read-only\n");
	}
}