utils.c (04.09.09)
exFAT file system implementation library.
- Copyright (C) 2009, 2010 Andrew Nayenko
+ Free exFAT implementation.
+ Copyright (C) 2010-2017 Andrew Nayenko
- This program is free software: you can redistribute it and/or modify
+ This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation, either version 3 of the License, or
+ the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "exfat.h"
#include <string.h>
#include <stdio.h>
#include <inttypes.h>
-#define _XOPEN_SOURCE /* for timezone in Linux */
-#include <time.h>
void exfat_stat(const struct exfat* ef, const struct exfat_node* node,
struct stat* stbuf)
{
memset(stbuf, 0, sizeof(struct stat));
- if (node->flags & EXFAT_ATTRIB_DIR)
+ if (node->attrib & EXFAT_ATTRIB_DIR)
stbuf->st_mode = S_IFDIR | (0777 & ~ef->dmask);
else
stbuf->st_mode = S_IFREG | (0777 & ~ef->fmask);
stbuf->st_uid = ef->uid;
stbuf->st_gid = ef->gid;
stbuf->st_size = node->size;
- stbuf->st_blocks = DIV_ROUND_UP(node->size, CLUSTER_SIZE(*ef->sb)) *
- CLUSTER_SIZE(*ef->sb) / 512;
+ stbuf->st_blocks = ROUND_UP(node->size, CLUSTER_SIZE(*ef->sb)) / 512;
stbuf->st_mtime = node->mtime;
stbuf->st_atime = node->atime;
/* set ctime to mtime to ensure we don't break programs that rely on ctime
stbuf->st_ctime = node->mtime;
}
-#define SEC_IN_MIN 60ll
-#define SEC_IN_HOUR (60 * SEC_IN_MIN)
-#define SEC_IN_DAY (24 * SEC_IN_HOUR)
-#define SEC_IN_YEAR (365 * SEC_IN_DAY) /* not leap year */
-/* Unix epoch started at 0:00:00 UTC 1 January 1970 */
-#define UNIX_EPOCH_YEAR 1970
-/* exFAT epoch started at 0:00:00 UTC 1 January 1980 */
-#define EXFAT_EPOCH_YEAR 1980
-/* number of years from Unix epoch to exFAT epoch */
-#define EPOCH_DIFF_YEAR (EXFAT_EPOCH_YEAR - UNIX_EPOCH_YEAR)
-/* number of days from Unix epoch to exFAT epoch (considering leap days) */
-#define EPOCH_DIFF_DAYS (EPOCH_DIFF_YEAR * 365 + EPOCH_DIFF_YEAR / 4)
-/* number of seconds from Unix epoch to exFAT epoch (considering leap days) */
-#define EPOCH_DIFF_SEC (EPOCH_DIFF_DAYS * SEC_IN_DAY)
-/* number of leap years passed from exFAT epoch to the specified year
- (excluding the specified year itself) */
-#define LEAP_YEARS(year) ((EXFAT_EPOCH_YEAR + (year) - 1) / 4 \
- - (EXFAT_EPOCH_YEAR - 1) / 4)
-/* checks whether the specified year is leap */
-#define IS_LEAP_YEAR(year) ((EXFAT_EPOCH_YEAR + (year)) % 4 == 0)
-
-static const time_t days_in_year[] =
+void exfat_get_name(const struct exfat_node* node,
+ char buffer[EXFAT_UTF8_NAME_BUFFER_MAX])
{
- /* 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
-};
+ if (utf16_to_utf8(buffer, node->name, EXFAT_UTF8_NAME_BUFFER_MAX,
+ EXFAT_NAME_MAX) != 0)
+ exfat_bug("failed to convert name to UTF-8");
+}
-time_t exfat_exfat2unix(le16_t date, le16_t time, uint8_t centisec)
+static uint16_t add_checksum_byte(uint16_t sum, uint8_t byte)
{
- time_t unix_time = EPOCH_DIFF_SEC;
- uint16_t ndate = le16_to_cpu(date);
- uint16_t ntime = le16_to_cpu(time);
-
- uint16_t day = ndate & 0x1f; /* 5 bits, 1-31 */
- uint16_t month = ndate >> 5 & 0xf; /* 4 bits, 1-12 */
- uint16_t year = ndate >> 9; /* 7 bits, 1-127 (+1980) */
-
- uint16_t twosec = ntime & 0x1f; /* 5 bits, 0-29 (2 sec granularity) */
- uint16_t min = ntime >> 5 & 0xf; /* 6 bits, 0-59 */
- uint16_t hour = ntime >> 11; /* 5 bits, 0-23 */
-
- if (day == 0 || month == 0 || month > 12)
- {
- exfat_error("bad date %hu-%02hu-%02hu",
- year + EXFAT_EPOCH_YEAR, month, day);
- return 0;
- }
- if (hour > 23 || min > 59 || twosec > 29)
- {
- exfat_error("bad time %hu:%02hu:%02hu",
- hour, min, twosec * 2);
- return 0;
- }
- if (centisec > 199)
- {
- exfat_error("bad centiseconds count %hhu", centisec);
- return 0;
- }
-
- /* every 4th year between 1904 and 2096 is leap */
- unix_time += year * SEC_IN_YEAR + LEAP_YEARS(year) * SEC_IN_DAY;
- unix_time += days_in_year[month] * SEC_IN_DAY;
- /* if it's leap year and February has passed we should add 1 day */
- if ((EXFAT_EPOCH_YEAR + year) % 4 == 0 && month > 2)
- unix_time += SEC_IN_DAY;
- unix_time += (day - 1) * SEC_IN_DAY;
-
- unix_time += hour * SEC_IN_HOUR;
- unix_time += min * SEC_IN_MIN;
- /* exFAT represents time with 2 sec granularity */
- unix_time += twosec * 2;
- unix_time += centisec / 100;
-
- /* exFAT stores timestamps in local time, so we correct it to UTC */
- unix_time += timezone;
-
- return unix_time;
+ return ((sum << 15) | (sum >> 1)) + byte;
}
-void exfat_unix2exfat(time_t unix_time, le16_t* date, le16_t* time,
- uint8_t* centisec)
+static uint16_t add_checksum_bytes(uint16_t sum, const void* buffer, size_t n)
{
- time_t shift = EPOCH_DIFF_SEC + timezone;
- uint16_t day, month, year;
- uint16_t twosec, min, hour;
- int days;
int i;
- /* time before exFAT epoch cannot be represented */
- if (unix_time < shift)
- unix_time = shift;
-
- unix_time -= shift;
-
- days = unix_time / SEC_IN_DAY;
- year = (4 * days) / (4 * 365 + 1);
- days -= year * 365 + LEAP_YEARS(year);
- month = 0;
- for (i = 1; i <= 12; i++)
- {
- int leap_day = (IS_LEAP_YEAR(year) && i == 2);
- int leap_sub = (IS_LEAP_YEAR(year) && i >= 3);
-
- if (i == 12 || days - leap_sub < days_in_year[i + 1] + leap_day)
- {
- month = i;
- days -= days_in_year[i] + leap_sub;
- break;
- }
- }
- day = days + 1;
-
- hour = (unix_time % SEC_IN_DAY) / SEC_IN_HOUR;
- min = (unix_time % SEC_IN_HOUR) / SEC_IN_MIN;
- twosec = (unix_time % SEC_IN_MIN) / 2;
-
- *date = cpu_to_le16(day | (month << 5) | (year << 9));
- *time = cpu_to_le16(twosec | (min << 5) | (hour << 11));
- if (centisec)
- *centisec = (unix_time % 2) * 100;
-}
-
-void exfat_get_name(const struct exfat_node* node, char* buffer, size_t n)
-{
- if (utf16_to_utf8(buffer, node->name, n, EXFAT_NAME_MAX) != 0)
- exfat_bug("failed to convert name to UTF-8");
+ for (i = 0; i < n; i++)
+ sum = add_checksum_byte(sum, ((const uint8_t*) buffer)[i]);
+ return sum;
}
uint16_t exfat_start_checksum(const struct exfat_entry_meta1* entry)
for (i = 0; i < sizeof(struct exfat_entry); i++)
if (i != 2 && i != 3) /* skip checksum field itself */
- sum = ((sum << 15) | (sum >> 1)) + ((const uint8_t*) entry)[i];
+ sum = add_checksum_byte(sum, ((const uint8_t*) entry)[i]);
return sum;
}
uint16_t exfat_add_checksum(const void* entry, uint16_t sum)
{
- int i;
-
- for (i = 0; i < sizeof(struct exfat_entry); i++)
- sum = ((sum << 15) | (sum >> 1)) + ((const uint8_t*) entry)[i];
- return sum;
+ return add_checksum_bytes(sum, entry, sizeof(struct exfat_entry));
}
-le16_t exfat_calc_checksum(const struct exfat_entry_meta1* meta1,
- const struct exfat_entry_meta2* meta2, const le16_t* name)
+le16_t exfat_calc_checksum(const struct exfat_entry* entries, int n)
{
uint16_t checksum;
- const int name_entries = DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX);
int i;
- checksum = exfat_start_checksum(meta1);
- checksum = exfat_add_checksum(meta2, checksum);
- for (i = 0; i < name_entries; i++)
- {
- struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
- memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
- EXFAT_ENAME_MAX * sizeof(le16_t));
- checksum = exfat_add_checksum(&name_entry, checksum);
- }
+ checksum = exfat_start_checksum((const struct exfat_entry_meta1*) entries);
+ for (i = 1; i < n; i++)
+ checksum = exfat_add_checksum(entries + i, checksum);
return cpu_to_le16(checksum);
}
return sum;
}
-
-le16_t exfat_calc_name_hash(const struct exfat* ef, const le16_t* name)
+le16_t exfat_calc_name_hash(const struct exfat* ef, const le16_t* name,
+ size_t length)
{
size_t i;
- size_t length = utf16_length(name);
uint16_t hash = 0;
for (i = 0; i < length; i++)
uint16_t c = le16_to_cpu(name[i]);
/* convert to upper case */
- if (c < ef->upcase_chars)
- c = le16_to_cpu(ef->upcase[c]);
+ c = ef->upcase[c];
hash = ((hash << 15) | (hash >> 1)) + (c & 0xff);
hash = ((hash << 15) | (hash >> 1)) + (c >> 8);
void exfat_humanize_bytes(uint64_t value, struct exfat_human_bytes* hb)
{
size_t i;
- const char* units[] = {"bytes", "KB", "MB", "GB", "TB", "PB"};
+ /* 16 EB (minus 1 byte) is the largest size that can be represented by
+ uint64_t */
+ const char* units[] = {"bytes", "KB", "MB", "GB", "TB", "PB", "EB"};
uint64_t divisor = 1;
uint64_t temp = 0;
- for (i = 0; i < sizeof(units) / sizeof(units[0]) - 1; i++, divisor *= 1024)
+ for (i = 0; ; i++, divisor *= 1024)
{
temp = (value + divisor / 2) / divisor;
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