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vfs/fatfs: use structures with bit fields for FAT date/time

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Replace explicit masks and shifts with bit fields when working with FATFS date and time representations. Also zero-initialize remaining members of struct tm.

Fixes https://github.com/espressif/esp-idf/issues/1369.
This commit is contained in:
Ivan Grokhotkov 2017-12-08 20:03:24 +08:00
parent a63ace15bd
commit dfee6e825a
1 changed files with 29 additions and 13 deletions
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42
components/fatfs/src/vfs_fat.c
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@ -43,6 +43,25 @@ typedef struct {
struct dirent cur_dirent;
} vfs_fat_dir_t;
/* Date and time storage formats in FAT */
typedef union {
struct {
uint16_t mday : 5; /* Day of month, 1 - 31 */
uint16_t mon : 4; /* Month, 1 - 12 */
uint16_t year : 7; /* Year, counting from 1980. E.g. 37 for 2017 */
};
uint16_t as_int;
} fat_date_t;
typedef union {
struct {
uint16_t sec : 5; /* Seconds divided by 2. E.g. 21 for 42 seconds */
uint16_t min : 6; /* Minutes, 0 - 59 */
uint16_t hour : 5; /* Hour, 0 - 23 */
};
uint16_t as_int;
} fat_time_t;
static const char* TAG = "vfs_fat";
static ssize_t vfs_fat_write(void* p, int fd, const void * data, size_t size);
@ -424,19 +443,16 @@ static int vfs_fat_stat(void* ctx, const char * path, struct stat * st)
memset(st, 0, sizeof(*st));
st->st_size = info.fsize;
st->st_mode = get_stat_mode((info.fattrib & AM_DIR) != 0);
struct tm tm;
uint16_t fdate = info.fdate;
tm.tm_mday = fdate & 0x1f;
fdate >>= 5;
tm.tm_mon = (fdate & 0xf) - 1;
fdate >>=4;
tm.tm_year = fdate + 80;
uint16_t ftime = info.ftime;
tm.tm_sec = (ftime & 0x1f) * 2;
ftime >>= 5;
tm.tm_min = (ftime & 0x3f);
ftime >>= 6;
tm.tm_hour = (ftime & 0x1f);
fat_date_t fdate = { .as_int = info.fdate };
fat_time_t ftime = { .as_int = info.ftime };
struct tm tm = {
.tm_mday = fdate.mday,
.tm_mon = fdate.mon - 1, /* unlike tm_mday, tm_mon is zero-based */
.tm_year = fdate.year + 80,
.tm_sec = ftime.sec * 2,
.tm_min = ftime.min,
.tm_hour = ftime.hour
};
st->st_mtime = mktime(&tm);
return 0;
}