?? tff.c
字號:
/*-----------------------------------------------------------------------*/
/* Open or Create a File */
/*-----------------------------------------------------------------------*/
FRESULT f_open (
FIL *fp, /* Pointer to the blank file object */
const char *path, /* Pointer to the file name */
BYTE mode /* Access mode and file open mode flags */
)
{
FRESULT res;
BYTE *dir;
DIR dirobj;
char fn[8+3+1];
FATFS *fs = FatFs;
fp->fs = NULL;
#if !_FS_READONLY
mode &= (FA_READ|FA_WRITE|FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW);
res = auto_mount(&path, (BYTE)(mode & (FA_WRITE|FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW)));
#else
mode &= FA_READ;
res = auto_mount(&path, 0);
#endif
if (res != FR_OK) return res;
/* Trace the file path */
res = trace_path(&dirobj, fn, path, &dir); /* Trace the file path */
#if !_FS_READONLY
/* Create or Open a File */
if (mode & (FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW)) {
CLUST rs;
DWORD dw;
if (res != FR_OK) { /* No file, create new */
if (res != FR_NO_FILE) return res;
res = reserve_direntry(&dirobj, &dir);
if (res != FR_OK) return res;
memset(dir, 0, 32); /* Initialize the new entry */
memcpy(&dir[DIR_Name], fn, 8+3);
dir[DIR_NTres] = fn[11];
mode |= FA_CREATE_ALWAYS;
} else { /* Any object is already existing */
if (mode & FA_CREATE_NEW) /* Cannot create new */
return FR_EXIST;
if (dir == NULL || (dir[DIR_Attr] & (AM_RDO|AM_DIR))) /* Cannot overwrite (R/O or DIR) */
return FR_DENIED;
if (mode & FA_CREATE_ALWAYS) { /* Resize it to zero */
#if _FAT32
rs = ((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) | LD_WORD(&dir[DIR_FstClusLO]);
ST_WORD(&dir[DIR_FstClusHI], 0);
#else
rs = LD_WORD(&dir[DIR_FstClusLO]);
#endif
ST_WORD(&dir[DIR_FstClusLO], 0); /* cluster = 0 */
ST_DWORD(&dir[DIR_FileSize], 0); /* size = 0 */
fs->winflag = 1;
dw = fs->winsect; /* Remove the cluster chain */
if (!remove_chain(rs) || !move_window(dw))
return FR_RW_ERROR;
fs->last_clust = rs - 1; /* Reuse the cluster hole */
}
}
if (mode & FA_CREATE_ALWAYS) {
dir[DIR_Attr] = AM_ARC; /* New attribute */
dw = get_fattime();
ST_DWORD(&dir[DIR_WrtTime], dw); /* Updated time */
ST_DWORD(&dir[DIR_CrtTime], dw); /* Created time */
fs->winflag = 1;
}
}
/* Open a File */
else {
#endif /* !_FS_READONLY */
if (res != FR_OK) return res; /* Trace failed */
if (dir == NULL || (dir[DIR_Attr] & AM_DIR)) /* It is a directory */
return FR_NO_FILE;
#if !_FS_READONLY
if ((mode & FA_WRITE) && (dir[DIR_Attr] & AM_RDO)) /* R/O violation */
return FR_DENIED;
}
fp->dir_sect = fs->winsect; /* Pointer to the directory entry */
fp->dir_ptr = dir;
#endif
fp->flag = mode; /* File access mode */
fp->org_clust = /* File start cluster */
#if _FAT32
((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) |
#endif
LD_WORD(&dir[DIR_FstClusLO]);
fp->fsize = LD_DWORD(&dir[DIR_FileSize]); /* File size */
fp->fptr = 0; /* File ptr */
fp->sect_clust = 1; /* Sector counter */
fp->fs = fs; fp->id = fs->id; /* Owner file system object of the file */
return FR_OK;
}
/*-----------------------------------------------------------------------*/
/* Read File */
/*-----------------------------------------------------------------------*/
FRESULT f_read (
FIL *fp, /* Pointer to the file object */
void *buff, /* Pointer to data buffer */
WORD btr, /* Number of bytes to read */
WORD *br /* Pointer to number of bytes read */
)
{
DWORD sect, remain;
WORD rcnt;
CLUST clust;
BYTE cc, *rbuff = buff;
FRESULT res;
FATFS *fs = fp->fs;
*br = 0;
res = validate(fs, fp->id); /* Check validity of the object */
if (res) return res;
if (fp->flag & FA__ERROR) return FR_RW_ERROR; /* Check error flag */
if (!(fp->flag & FA_READ)) return FR_DENIED; /* Check access mode */
remain = fp->fsize - fp->fptr;
if (btr > remain) btr = (WORD)remain; /* Truncate read count by number of bytes left */
for ( ; btr; /* Repeat until all data transferred */
rbuff += rcnt, fp->fptr += rcnt, *br += rcnt, btr -= rcnt) {
if ((fp->fptr % 512) == 0) { /* On the sector boundary */
if (--fp->sect_clust) { /* Decrement left sector counter */
sect = fp->curr_sect + 1; /* Get current sector */
} else { /* On the cluster boundary, get next cluster */
clust = (fp->fptr == 0) ?
fp->org_clust : get_cluster(fp->curr_clust);
if (clust < 2 || clust >= fs->max_clust)
goto fr_error;
fp->curr_clust = clust; /* Current cluster */
sect = clust2sect(clust); /* Get current sector */
fp->sect_clust = fs->sects_clust; /* Re-initialize the left sector counter */
}
fp->curr_sect = sect; /* Update current sector */
cc = btr / 512; /* When left bytes >= 512, */
if (cc) { /* Read maximum contiguous sectors directly */
if (cc > fp->sect_clust) cc = fp->sect_clust;
if (disk_read(0, rbuff, sect, cc) != RES_OK)
goto fr_error;
fp->sect_clust -= cc - 1;
fp->curr_sect += cc - 1;
rcnt = cc * 512; continue;
}
}
if (!move_window(fp->curr_sect)) goto fr_error; /* Move sector window */
rcnt = 512 - (WORD)(fp->fptr % 512); /* Copy fractional bytes from sector window */
if (rcnt > btr) rcnt = btr;
memcpy(rbuff, &fs->win[(WORD)fp->fptr % 512], rcnt);
}
return FR_OK;
fr_error: /* Abort this function due to an unrecoverable error */
fp->flag |= FA__ERROR;
return FR_RW_ERROR;
}
#if !_FS_READONLY
/*-----------------------------------------------------------------------*/
/* Write File */
/*-----------------------------------------------------------------------*/
FRESULT f_write (
FIL *fp, /* Pointer to the file object */
const void *buff, /* Pointer to the data to be written */
WORD btw, /* Number of bytes to write */
WORD *bw /* Pointer to number of bytes written */
)
{
DWORD sect;
WORD wcnt;
CLUST clust;
BYTE cc;
FRESULT res;
const BYTE *wbuff = buff;
FATFS *fs = fp->fs;
*bw = 0;
res = validate(fs, fp->id); /* Check validity of the object */
if (res) return res;
if (fp->flag & FA__ERROR) return FR_RW_ERROR; /* Check error flag */
if (!(fp->flag & FA_WRITE)) return FR_DENIED; /* Check access mode */
if (fp->fsize + btw < fp->fsize) return FR_OK; /* File size cannot reach 4GB */
for ( ; btw; /* Repeat until all data transferred */
wbuff += wcnt, fp->fptr += wcnt, *bw += wcnt, btw -= wcnt) {
if ((fp->fptr % 512) == 0) { /* On the sector boundary */
if (--(fp->sect_clust)) { /* Decrement left sector counter */
sect = fp->curr_sect + 1; /* Get current sector */
} else { /* On the cluster boundary, get next cluster */
if (fp->fptr == 0) { /* Is top of the file */
clust = fp->org_clust;
if (clust == 0) /* No cluster is created yet */
fp->org_clust = clust = create_chain(0); /* Create a new cluster chain */
} else { /* Middle or end of file */
clust = create_chain(fp->curr_clust); /* Trace or streach cluster chain */
}
if (clust == 0) break; /* Disk full */
if (clust == 1 || clust >= fs->max_clust) goto fw_error;
fp->curr_clust = clust; /* Current cluster */
sect = clust2sect(clust); /* Get current sector */
fp->sect_clust = fs->sects_clust; /* Re-initialize the left sector counter */
}
fp->curr_sect = sect; /* Update current sector */
cc = btw / 512; /* When left bytes >= 512, */
if (cc) { /* Write maximum contiguous sectors directly */
if (cc > fp->sect_clust) cc = fp->sect_clust;
if (disk_write(0, wbuff, sect, cc) != RES_OK)
goto fw_error;
fp->sect_clust -= cc - 1;
fp->curr_sect += cc - 1;
wcnt = cc * 512; continue;
}
if (fp->fptr >= fp->fsize) { /* Flush R/W window if needed */
if (!move_window(0)) goto fw_error;
fs->winsect = fp->curr_sect;
}
}
if (!move_window(fp->curr_sect)) /* Move sector window */
goto fw_error;
wcnt = 512 - (WORD)(fp->fptr % 512); /* Copy fractional bytes bytes to sector window */
if (wcnt > btw) wcnt = btw;
memcpy(&fs->win[(WORD)fp->fptr % 512], wbuff, wcnt);
fs->winflag = 1;
}
if (fp->fptr > fp->fsize) fp->fsize = fp->fptr; /* Update file size if needed */
fp->flag |= FA__WRITTEN; /* Set file changed flag */
return FR_OK;
fw_error: /* Abort this function due to an unrecoverable error */
fp->flag |= FA__ERROR;
return FR_RW_ERROR;
}
/*-----------------------------------------------------------------------*/
/* Synchronize between File and Disk */
/*-----------------------------------------------------------------------*/
FRESULT f_sync (
FIL *fp /* Pointer to the file object */
)
{
DWORD tim;
BYTE *dir;
FRESULT res;
FATFS *fs = fp->fs;
res = validate(fs, fp->id); /* Check validity of the object */
if (res == FR_OK) {
if (fp->flag & FA__WRITTEN) { /* Has the file been written? */
/* Update the directory entry */
if (!move_window(fp->dir_sect))
return FR_RW_ERROR;
dir = fp->dir_ptr;
dir[DIR_Attr] |= AM_ARC; /* Set archive bit */
ST_DWORD(&dir[DIR_FileSize], fp->fsize); /* Update file size */
ST_WORD(&dir[DIR_FstClusLO], fp->org_clust); /* Update start cluster */
#if _FAT32
ST_WORD(&dir[DIR_FstClusHI], fp->org_clust >> 16);
#endif
tim = get_fattime(); /* Updated time */
ST_DWORD(&dir[DIR_WrtTime], tim);
fp->flag &= ~FA__WRITTEN;
res = sync();
}
}
return res;
}
#endif /* !_FS_READONLY */
/*-----------------------------------------------------------------------*/
/* Close File */
/*-----------------------------------------------------------------------*/
FRESULT f_close (
FIL *fp /* Pointer to the file object to be closed */
)
{
FRESULT res;
#if !_FS_READONLY
res = f_sync(fp);
#else
res = validate(fp->fs, fp->id);
#endif
if (res == FR_OK)
fp->fs = NULL;
return res;
}
#if _FS_MINIMIZE <= 2
/*-----------------------------------------------------------------------*/
/* Seek File Pointer */
/*-----------------------------------------------------------------------*/
FRESULT f_lseek (
FIL *fp, /* Pointer to the file object */
DWORD ofs /* File pointer from top of file */
)
{
CLUST clust;
DWORD csize;
BYTE csect;
FRESULT res;
FATFS *fs = fp->fs;
res = validate(fs, fp->id); /* Check validity of the object */
if (res) return res;
if (fp->flag & FA__ERROR) return FR_RW_ERROR;
#if !_FS_READONLY
if (ofs > fp->fsize && !(fp->flag & FA_WRITE))
#else
if (ofs > fp->fsize)
#endif
ofs = fp->fsize;
fp->fptr = 0; fp->sect_clust = 1; /* Set file R/W pointer to top of the file */
/* Move file R/W pointer if needed */
if (ofs) {
clust = fp->org_clust; /* Get start cluster */
#if !_FS_READONLY
if (!clust) { /* If the file does not have a cluster chain, create new cluster chain */
clust = create_chain(0);
if (clust == 1) goto fk_error;
fp->org_clust = clust;
}
#endif
if (clust) { /* If the file has a cluster chain, it can be followed */
csize = (DWORD)fs->sects_clust * 512; /* Cluster size in unit of byte */
for (;;) { /* Loop to skip leading clusters */
fp->curr_clust = clust; /* Update current cluster */
if (ofs <= csize) break;
#if !_FS_READONLY
if (fp->flag & FA_WRITE) /* Check if in write mode or not */
clust = create_chain(clust); /* Force streached if in write mode */
else
#endif
clust = get_cluster(clust); /* Only follow cluster chain if not in write mode */
if (clust == 0) { /* Stop if could not follow the cluster chain */
ofs = csize; break;
}
if (clust == 1 || clust >= fs->max_clust) goto fk_error;
fp->fptr += csize; /* Update R/W pointer */
ofs -= csize;
}
csect = (BYTE)((ofs - 1) / 512); /* Sector offset in the cluster */
fp->curr_sect = clust2sect(clust) + csect; /* Current sector */
fp->sect_clust = fs->sects_clust - csect; /* Left sector counter in the cluster */
fp->fptr += ofs; /* Update file R/W pointer */
}
}
#if !_FS_READONLY
if ((fp->flag & FA_WRITE) && fp->fptr > fp->fsize) { /* Set updated flag if in write mode */
fp->fsize = fp->fptr;
fp->flag |= FA__WRITTEN;
}
#endif
return FR_OK;
fk_error: /* Abort this function due to an unrecoverable error */
fp->flag |= FA__ERROR;
return FR_RW_ERROR;
}
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