/*--------------------------------------------------------------------------/
/  FatFs - FAT file system module  R0.04b                    (C)ChaN, 2007
/---------------------------------------------------------------------------/
/ The FatFs module is an experimenal project to implement FAT file system to
/ cheap microcontrollers. This is a free software and is opened for education,
/ research and development under license policy of following trems.
/
/  Copyright (C) 2007, ChaN, all right reserved.
/
/ * The FatFs module is a free software and there is no warranty.
/ * You can use, modify and/or redistribute it for personal, non-profit or
/   profit use without any restriction under your responsibility.
/ * Redistributions of source code must retain the above copyright notice.
/
/---------------------------------------------------------------------------/
/  Feb 26, 2006  R0.00  Prototype.
/  Apr 29, 2006  R0.01  First stable version.
/  Jun 01, 2006  R0.02  Added FAT12 support.
/                       Removed unbuffered mode.
/                       Fixed a problem on small (<32M) patition.
/  Jun 10, 2006  R0.02a Added a configuration option (_FS_MINIMUM).
/  Sep 22, 2006  R0.03  Added f_rename().
/                       Changed option _FS_MINIMUM to _FS_MINIMIZE.
/  Dec 11, 2006  R0.03a Improved cluster scan algolithm to write files fast.
/                       Fixed f_mkdir() creates incorrect directory on FAT32.
/  Feb 04, 2007  R0.04  Supported multiple drive system.
/                       Changed some interfaces for multiple drive system.
/                       Changed f_mountdrv() to f_mount().
/                       Added f_mkfs().
/  Apr 01, 2007  R0.04a Supported multiple partitions on a plysical drive.
/                       Added a capability of extending file size to f_lseek().
/                       Added minimization level 3.
/                       Fixed an endian sensitive code in f_mkfs().
/  May 05, 2007  R0.04b Added a configuration option _USE_NTFLAG.
/                       Added FSInfo support.
/                       Fixed DBCS name can result FR_INVALID_NAME.
/                       Fixed short seek (<= csize) collapses the file object.
/---------------------------------------------------------------------------*/

#include <string.h>
#include "third_party/fatfs/src/ff.h"            /* FatFs declarations */
#include "third_party/fatfs/src/diskio.h"        /* Include file for user provided disk functions */


/*--------------------------------------------------------------------------

   Module Private Functions

---------------------------------------------------------------------------*/

static
FATFS *FatFs[_DRIVES];    /* Pointer to the file system objects (logical drives) */
static
WORD fsid;                /* File system mount ID */



/*-----------------------------------------------------------------------*/
/* Change window offset                                                  */
/*-----------------------------------------------------------------------*/

static
BOOL move_window (        /* TRUE: successful, FALSE: failed */
    FATFS *fs,            /* File system object */
    DWORD sector        /* Sector number to make apperance in the fs->win[] */
)                        /* Move to zero only writes back dirty window */
{
    DWORD wsect;


    wsect = fs->winsect;
    if (wsect != sector) {    /* Changed current window */
#if !_FS_READONLY
        BYTE n;
        if (fs->winflag) {    /* Write back dirty window if needed */
            if (disk_write(fs->drive, fs->win, wsect, 1) != RES_OK)
                return FALSE;
            fs->winflag = 0;
            if (wsect < (fs->fatbase + fs->sects_fat)) {    /* In FAT area */
                for (n = fs->n_fats; n >= 2; n--) {    /* Refrect the change to FAT copy */
                    wsect += fs->sects_fat;
                    disk_write(fs->drive, fs->win, wsect, 1);
                }
            }
        }
#endif
        if (sector) {
            if (disk_read(fs->drive, fs->win, sector, 1) != RES_OK)
                return FALSE;
            fs->winsect = sector;
        }
    }
    return TRUE;
}




/*-----------------------------------------------------------------------*/
/* Clean-up cached data                                                  */
/*-----------------------------------------------------------------------*/

#if !_FS_READONLY
static
FRESULT sync (            /* FR_OK: successful, FR_RW_ERROR: failed */
    FATFS *fs            /* File system object */
)
{
    fs->winflag = 1;
    if (!move_window(fs, 0)) return FR_RW_ERROR;
#if _USE_FSINFO
    if (fs->fs_type == FS_FAT32 && fs->fsi_flag) {        /* Update FSInfo sector if needed */
        fs->winsect = 0;
        memset(fs->win, 0, 512);
        ST_WORD(&fs->win[BS_55AA], 0xAA55);
        ST_DWORD(&fs->win[FSI_LeadSig], 0x41615252);
        ST_DWORD(&fs->win[FSI_StrucSig], 0x61417272);
        ST_DWORD(&fs->win[FSI_Free_Count], fs->free_clust);
        ST_DWORD(&fs->win[FSI_Nxt_Free], fs->last_clust);
        disk_write(0, fs->win, fs->fsi_sector, 1);
        fs->fsi_flag = 0;
    }
#endif
    if (disk_ioctl(fs->drive, CTRL_SYNC, NULL) != RES_OK) return FR_RW_ERROR;
    return FR_OK;
}
#endif




/*-----------------------------------------------------------------------*/
/* Get a cluster status                                                  */
/*-----------------------------------------------------------------------*/

static
DWORD get_cluster (        /* 0,>=2: successful, 1: failed */
    FATFS *fs,            /* File system object */
    DWORD clust            /* Cluster# to get the link information */
)
{
    WORD wc, bc;
    DWORD fatsect;


    if (clust >= 2 && clust < fs->max_clust) {        /* Valid cluster# */
        fatsect = fs->fatbase;
        switch (fs->fs_type) {
        case FS_FAT12 :
            bc = (WORD)clust * 3 / 2;
            if (!move_window(fs, fatsect + (bc / S_SIZ))) break;
            wc = fs->win[bc & (S_SIZ - 1)]; bc++;
            if (!move_window(fs, fatsect + (bc / S_SIZ))) break;
            wc |= (WORD)fs->win[bc & (S_SIZ - 1)] << 8;
            return (clust & 1) ? (wc >> 4) : (wc & 0xFFF);

        case FS_FAT16 :
            if (!move_window(fs, fatsect + (clust / (S_SIZ / 2)))) break;
            return LD_WORD(&fs->win[((WORD)clust * 2) & (S_SIZ - 1)]);

        case FS_FAT32 :
            if (!move_window(fs, fatsect + (clust / (S_SIZ / 4)))) break;
            return LD_DWORD(&fs->win[((WORD)clust * 4) & (S_SIZ - 1)]) & 0x0FFFFFFF;
        }
    }

    return 1;    /* There is no cluster information, or an error occured */
}




/*-----------------------------------------------------------------------*/
/* Change a cluster status                                               */
/*-----------------------------------------------------------------------*/

#if !_FS_READONLY
static
BOOL put_cluster (        /* TRUE: successful, FALSE: failed */
    FATFS *fs,            /* File system object */
    DWORD clust,        /* Cluster# to change */
    DWORD val            /* New value to mark the cluster */
)
{
    WORD bc;
    BYTE *p;
    DWORD fatsect;


    fatsect = fs->fatbase;
    switch (fs->fs_type) {
    case FS_FAT12 :
        bc = (WORD)clust * 3 / 2;
        if (!move_window(fs, fatsect + (bc / S_SIZ))) return FALSE;
        p = &fs->win[bc & (S_SIZ - 1)];
        *p = (clust & 1) ? ((*p & 0x0F) | ((BYTE)val << 4)) : (BYTE)val;
        bc++;
        fs->winflag = 1;
        if (!move_window(fs, fatsect + (bc / S_SIZ))) return FALSE;
        p = &fs->win[bc & (S_SIZ - 1)];
        *p = (clust & 1) ? (BYTE)(val >> 4) : ((*p & 0xF0) | ((BYTE)(val >> 8) & 0x0F));
        break;

    case FS_FAT16 :
        if (!move_window(fs, fatsect + (clust / (S_SIZ / 2)))) return FALSE;
        ST_WORD(&fs->win[((WORD)clust * 2) & (S_SIZ - 1)], (WORD)val);
        break;

    case FS_FAT32 :
        if (!move_window(fs, fatsect + (clust / (S_SIZ / 4)))) return FALSE;
        ST_DWORD(&fs->win[((WORD)clust * 4) & (S_SIZ - 1)], val);
        break;

    default :
        return FALSE;
    }
    fs->winflag = 1;
    return TRUE;
}
#endif /* !_FS_READONLY */




/*-----------------------------------------------------------------------*/
/* Remove a cluster chain                                                */
/*-----------------------------------------------------------------------*/

#if !_FS_READONLY
static
BOOL remove_chain (        /* TRUE: successful, FALSE: failed */
    FATFS *fs,            /* File system object */
    DWORD clust            /* Cluster# to remove chain from */
)
{
    DWORD nxt;


    while (clust >= 2 && clust < fs->max_clust) {
        nxt = get_cluster(fs, clust);
        if (nxt == 1) return FALSE;
        if (!put_cluster(fs, clust, 0)) return FALSE;
        if (fs->free_clust != 0xFFFFFFFF) {
            fs->free_clust++;
#if _USE_FSINFO
            fs->fsi_flag = 1;
#endif
        }
        clust = nxt;
    }
    return TRUE;
}
#endif




/*-----------------------------------------------------------------------*/
/* Stretch or create a cluster chain                                     */
/*-----------------------------------------------------------------------*/

#if !_FS_READONLY
static
DWORD create_chain (    /* 0: no free cluster, 1: error, >=2: new cluster number */
    FATFS *fs,            /* File system object */
    DWORD clust            /* Cluster# to stretch, 0 means create new */
)
{
    DWORD cstat, ncl, scl, mcl = fs->max_clust;


    if (clust == 0) {        /* Create new chain */
        scl = fs->last_clust;            /* Get suggested start point */
        if (scl == 0 || scl >= mcl) scl = 1;
    }
    else {                    /* Stretch existing chain */
        cstat = get_cluster(fs, clust);    /* Check the cluster status */
        if (cstat < 2) return 1;        /* It is an invalid cluster */
        if (cstat < mcl) return cstat;    /* It is already followed by next cluster */
        scl = clust;
    }

    ncl = scl;                /* Start cluster */
    for (;;) {
        ncl++;                            /* Next cluster */
        if (ncl >= mcl) {                /* Wrap around */
            ncl = 2;
            if (ncl > scl) return 0;    /* No free custer */
        }
        cstat = get_cluster(fs, ncl);    /* Get the cluster status */
        if (cstat == 0) break;            /* Found a free cluster */
        if (cstat == 1) return 1;        /* Any error occured */
        if (ncl == scl) return 0;        /* No free custer */
    }

    if (!put_cluster(fs, ncl, 0x0FFFFFFF)) return 1;        /* Mark the new cluster "in use" */
    if (clust && !put_cluster(fs, clust, ncl)) return 1;    /* Link it to previous one if needed */

    fs->last_clust = ncl;                /* Update fsinfo */
    if (fs->free_clust != 0xFFFFFFFF) {
        fs->free_clust--;
#if _USE_FSINFO
        fs->fsi_flag = 1;
#endif
    }

    return ncl;        /* Return new cluster number */
}
#endif /* !_FS_READONLY */




/*-----------------------------------------------------------------------*/
/* Get sector# from cluster#                                             */
/*-----------------------------------------------------------------------*/

static
DWORD clust2sect (    /* !=0: sector number, 0: failed - invalid cluster# */
    FATFS *fs,        /* File system object */
    DWORD clust        /* Cluster# to be converted */
)
{
    clust -= 2;
    if (clust >= (fs->max_clust - 2)) return 0;        /* Invalid cluster# */
    return clust * fs->sects_clust + fs->database;
}




/*-----------------------------------------------------------------------*/
/* Move directory pointer to next                                        */
/*-----------------------------------------------------------------------*/

static
BOOL next_dir_entry (    /* TRUE: successful, FALSE: could not move next */
    DIR *dirobj            /* Pointer to directory object */
)
{
    DWORD clust;
    WORD idx;
    FATFS *fs = dirobj->fs;


    idx = dirobj->index + 1;
    if ((idx & ((S_SIZ - 1) / 32)) == 0) {        /* Table sector changed? */
        dirobj->sect++;            /* Next sector */
        if (!dirobj->clust) {        /* In static table */
            if (idx >= fs->n_rootdir) return FALSE;    /* Reached to end of table */
        } else {                    /* In dynamic table */
            if (((idx / (S_SIZ / 32)) & (fs->sects_clust - 1)) == 0) {    /* Cluster changed? */
                clust = get_cluster(fs, dirobj->clust);        /* Get next cluster */
                if (clust < 2 || clust >= fs->max_clust)    /* Reached to end of table */
                    return FALSE;
                dirobj->clust = clust;                /* Initialize for new cluster */
                dirobj->sect = clust2sect(fs, clust);
            }
        }
    }
    dirobj->index = idx;    /* Lower 4 bit of dirobj->index indicates offset in dirobj->sect */
    return TRUE;
}




/*-----------------------------------------------------------------------*/
/* Get file status from directory entry                                  */
/*-----------------------------------------------------------------------*/

#if _FS_MINIMIZE <= 1
static
void get_fileinfo (        /* No return code */
    FILINFO *finfo,     /* Ptr to store the file information */
    const BYTE *dir        /* Ptr to the directory entry */
)
{
    BYTE n, c, a;
    char *p;


    p = &finfo->fname[0];
    a = _USE_NTFLAG ? dir[DIR_NTres] : 0;        /* NT flag */
    for (n = 0; n < 8; n++) {    /* Convert file name (body) */
        c = dir[n];
        if (c == ' ') break;
        if (c == 0x05) c = 0xE5;
        if (a & 0x08 && c >= 'A' && c <= 'Z') c += 0x20;
        *p++ = c;
    }
    if (dir[8] != ' ') {        /* Convert file name (extension) */
        *p++ = '.';
        for (n = 8; n < 11; n++) {
            c = dir[n];
            if (c == ' ') break;
            if (a & 0x10 && c >= 'A' && c <= 'Z') c += 0x20;
            *p++ = c;
        }
    }
    *p = '\0';

    finfo->fattrib = dir[DIR_Attr];                    /* Attribute */
    finfo->fsize = LD_DWORD(&dir[DIR_FileSize]);    /* Size */
    finfo->fdate = LD_WORD(&dir[DIR_WrtDate]);        /* Date */
    finfo->ftime = LD_WORD(&dir[DIR_WrtTime]);        /* Time */
}
#endif /* _FS_MINIMIZE <= 1 */




/*-----------------------------------------------------------------------*/
/* Pick a paragraph and create the name in format of directory entry     */
/*-----------------------------------------------------------------------*/

static
char make_dirfile (            /* 1: error - detected an invalid format, '\0'or'/': next character */
    const char **path,        /* Pointer to the file path pointer */
    char *dirname            /* Pointer to directory name buffer {Name(8), Ext(3), NT flag(1)} */
)
{
    BYTE n, t, c, a, b;


    memset(dirname, ' ', 8+3);    /* Fill buffer with spaces */
    a = 0; b = 0x18;    /* NT flag */
    n = 0; t = 8;
    for (;;) {
        c = *(*path)++;
        if (c == '\0' || c == '/') {        /* Reached to end of str or directory separator */
            if (n == 0) break;
            dirname[11] = _USE_NTFLAG ? (a & b) : 0;
            return c;
        }
        if (c <= ' ' || c == 0x7F) break;        /* Reject invisible chars */
        if (c == '.') {
            if (!(a & 1) && n >= 1 && n <= 8) {    /* Enter extension part */
                n = 8; t = 11; continue;
            }
            break;
        }
        if (_USE_SJIS &&
            ((c >= 0x81 && c <= 0x9F) ||    /* Accept S-JIS code */
            (c >= 0xE0 && c <= 0xFC))) {
            if (n == 0 && c == 0xE5)        /* Change heading \xE5 to \x05 */
                c = 0x05;
            a ^= 1; goto md_l2;
        }
        if (c == '"') break;                /* Reject " */
        if (c <= ')') goto md_l1;            /* Accept ! # $ % & ' ( ) */
        if (c <= ',') break;                /* Reject * + , */
        if (c <= '9') goto md_l1;            /* Accept - 0-9 */
        if (c <= '?') break;                /* Reject : ; < = > ? */
        if (!(a & 1)) {    /* These checks are not applied to S-JIS 2nd byte */
            if (c == '|') break;            /* Reject | */
            if (c >= '[' && c <= ']') break;/* Reject [ \ ] */
            if (_USE_NTFLAG && c >= 'A' && c <= 'Z')
                (t == 8) ? (b &= ~0x08) : (b &= ~0x10);
            if (c >= 'a' && c <= 'z') {        /* Convert to upper case */
                c -= 0x20;
                if (_USE_NTFLAG) (t == 8) ? (a |= 0x08) : (a |= 0x10);
            }
        }
    md_l1:
        a &= ~1;
    md_l2:
        if (n >= t) break;
        dirname[n++] = c;
    }
    return 1;
}




/*-----------------------------------------------------------------------*/
/* Trace a file path                                                     */
/*-----------------------------------------------------------------------*/

static
FRESULT trace_path (    /* FR_OK(0): successful, !=0: error code */
    DIR *dirobj,        /* Pointer to directory object to return last directory */
    char *fn,            /* Pointer to last segment name to return {file(8),ext(3),attr(1)} */
    const char *path,    /* Full-path string to trace a file or directory */
    BYTE **dir            /* Directory pointer in Win[] to retutn */
)
{
    DWORD clust;
    char ds;
    BYTE *dptr = NULL;
    FATFS *fs = dirobj->fs;    /* Get logical drive from the given DIR structure */


    /* Initialize directory object */
    clust = fs->dirbase;
    if (fs->fs_type == FS_FAT32) {
        dirobj->clust = dirobj->sclust = clust;
        dirobj->sect = clust2sect(fs, clust);
    } else {
        dirobj->clust = dirobj->sclust = 0;
        dirobj->sect = clust;
    }
    dirobj->index = 0;

    if (*path == '\0') {                    /* Null path means the root directory */
        *dir = NULL; return FR_OK;
    }

    for (;;) {
        ds = make_dirfile(&path, fn);            /* Get a paragraph into fn[] */
        if (ds == 1) return FR_INVALID_NAME;
        for (;;) {
            if (!move_window(fs, dirobj->sect)) return FR_RW_ERROR;
            dptr = &fs->win[(dirobj->index & ((S_SIZ - 1) / 32)) * 32];    /* Pointer to the directory entry */
            if (dptr[DIR_Name] == 0)                        /* Has it reached to end of dir? */
                return !ds ? FR_NO_FILE : FR_NO_PATH;
            if (dptr[DIR_Name] != 0xE5                        /* Matched? */
                && !(dptr[DIR_Attr] & AM_VOL)
                && !memcmp(&dptr[DIR_Name], fn, 8+3) ) break;
            if (!next_dir_entry(dirobj))                    /* Next directory pointer */
                return !ds ? FR_NO_FILE : FR_NO_PATH;
        }
        if (!ds) { *dir = dptr; return FR_OK; }                /* Matched with end of path */
        if (!(dptr[DIR_Attr] & AM_DIR)) return FR_NO_PATH;    /* Cannot trace because it is a file */
        clust = ((DWORD)LD_WORD(&dptr[DIR_FstClusHI]) << 16) | LD_WORD(&dptr[DIR_FstClusLO]); /* Get cluster# of the directory */
        dirobj->clust = dirobj->sclust = clust;                /* Restart scanning at the new directory */
        dirobj->sect = clust2sect(fs, clust);
        dirobj->index = 2;
    }
}




/*-----------------------------------------------------------------------*/
/* Reserve a directory entry                                             */
/*-----------------------------------------------------------------------*/

#if !_FS_READONLY
static
FRESULT reserve_direntry (    /* FR_OK: successful, FR_DENIED: no free entry, FR_RW_ERROR: a disk error occured */
    DIR *dirobj,            /* Target directory to create new entry */
    BYTE **dir                /* Pointer to pointer to created entry to retutn */
)
{
    DWORD clust, sector;
    BYTE c, n, *dptr;
    FATFS *fs = dirobj->fs;


    /* Re-initialize directory object */
    clust = dirobj->sclust;
    if (clust) {    /* Dyanmic directory table */
        dirobj->clust = clust;
        dirobj->sect = clust2sect(fs, clust);
    } else {        /* Static directory table */
        dirobj->sect = fs->dirbase;
    }
    dirobj->index = 0;

    do {
        if (!move_window(fs, dirobj->sect)) return FR_RW_ERROR;
        dptr = &fs->win[(dirobj->index & ((S_SIZ - 1) / 32)) * 32];    /* Pointer to the directory entry */
        c = dptr[DIR_Name];
        if (c == 0 || c == 0xE5) {            /* Found an empty entry! */
            *dir = dptr; return FR_OK;
        }
    } while (next_dir_entry(dirobj));                /* Next directory pointer */
    /* Reached to end of the directory table */

    /* Abort when static table or could not stretch dynamic table */
    if (!clust || !(clust = create_chain(fs, dirobj->clust))) return FR_DENIED;
    if (clust == 1 || !move_window(fs, 0)) return FR_RW_ERROR;

    fs->winsect = sector = clust2sect(fs, clust);        /* Cleanup the expanded table */
    memset(fs->win, 0, S_SIZ);
    for (n = fs->sects_clust; n; n--) {
        if (disk_write(fs->drive, fs->win, sector, 1) != RES_OK)
            return FR_RW_ERROR;
        sector++;
    }
    fs->winflag = 1;
    *dir = fs->win;
    return FR_OK;
}
#endif /* !_FS_READONLY */




/*-----------------------------------------------------------------------*/
/* Load boot record and check if it is a FAT boot record                 */
/*-----------------------------------------------------------------------*/

static
BYTE check_fs (        /* 0:The FAT boot record, 1:Valid boot record but not an FAT, 2:Not a boot record or error */
    FATFS *fs,        /* File system object */
    DWORD sect        /* Sector# (lba) to check if it is a FAT boot record or not */
)
{
    if (disk_read(fs->drive, fs->win, sect, 1) != RES_OK)    /* Load boot record */
        return 2;
    if (LD_WORD(&fs->win[BS_55AA]) != 0xAA55)                /* Check record signature (always offset 510) */
        return 2;

    if (!memcmp(&fs->win[BS_FilSysType], "FAT", 3))            /* Check FAT signature */
        return 0;
    if (!memcmp(&fs->win[BS_FilSysType32], "FAT32", 5) && !(fs->win[BPB_ExtFlags] & 0x80))
        return 0;

    return 1;
}




/*-----------------------------------------------------------------------*/
/* Make sure that the file system is valid                               */
/*-----------------------------------------------------------------------*/

static
FRESULT auto_mount (        /* FR_OK(0): successful, !=0: any error occured */
    const char **path,        /* Pointer to pointer to the path name (drive number) */
    FATFS **rfs,            /* Pointer to pointer to the found file system object */
    BYTE chk_wp                /* !=0: Check media write protection for wrinting fuctions */
)
{
    BYTE drv, fmt, *tbl;
    DSTATUS stat;
    DWORD bootsect, fatsize, totalsect, maxclust;
    const char *p = *path;
    FATFS *fs;


    /* Get drive number from the path name */
    while (*p == ' ') p++;        /* Strip leading spaces */
    drv = p[0] - '0';            /* Is there a drive number? */
    if (drv <= 9 && p[1] == ':')
        p += 2;            /* Found a drive number, get and strip it */
    else
        drv = 0;        /* No drive number is given, select drive 0 in default */
    if (*p == '/') p++;    /* Strip heading slash */
    *path = p;            /* Return pointer to the path name */

    /* Check if the drive number is valid or not */
    if (drv >= _DRIVES) return FR_INVALID_DRIVE;    /* Is the drive number valid? */
    if (!(fs = FatFs[drv])) return FR_NOT_ENABLED;    /* Is the file system object registered? */
    *rfs = fs;            /* Returen pointer to the corresponding file system object */

    /* Check if the logical drive has been mounted or not */
    if (fs->fs_type) {
        stat = disk_status(fs->drive);
        if (!(stat & STA_NOINIT)) {                /* If the physical drive is kept initialized */
#if !_FS_READONLY
            if (chk_wp && (stat & STA_PROTECT))    /* Check write protection if needed */
                return FR_WRITE_PROTECTED;
#endif
            return FR_OK;                        /* The file system object is valid */
        }
    }

    /* The logical drive has not been mounted, following code attempts to mount the logical drive */

    memset(fs, 0, sizeof(FATFS));        /* Clean-up the file system object */
    fs->drive = LD2PD(drv);                /* Bind the logical drive and a physical drive */
    stat = disk_initialize(fs->drive);    /* Initialize low level disk I/O layer */
    if (stat & STA_NOINIT)                /* Check if the drive is ready */
        return FR_NOT_READY;
#if S_MAX_SIZ > 512                        /* Check disk sector size */
    if (disk_ioctl(drv, GET_SECTOR_SIZE, &S_SIZ) != RES_OK || S_SIZ > S_MAX_SIZ)
        return FR_NO_FILESYSTEM;
#endif
#if !_FS_READONLY
    if (chk_wp && (stat & STA_PROTECT))    /* Check write protection if needed */
        return FR_WRITE_PROTECTED;
#endif
    /* Search FAT partition on the drive */
    fmt = check_fs(fs, bootsect = 0);    /* Check sector 0 as an SFD format */
    if (fmt == 1) {                        /* Not a FAT boot record, it may be patitioned */
        /* Check a partition listed in top of the partition table */
        tbl = &fs->win[MBR_Table + LD2PT(drv) * 16];    /* Partition table */
        if (tbl[4]) {                                /* Is the partition existing? */
            bootsect = LD_DWORD(&tbl[8]);            /* Partition offset in LBA */
            fmt = check_fs(fs, bootsect);            /* Check the partition */
        }
    }
    if (fmt || LD_WORD(&fs->win[BPB_BytsPerSec]) != S_SIZ)    /* No valid FAT patition is found */
        return FR_NO_FILESYSTEM;

    /* Initialize the file system object */
    fatsize = LD_WORD(&fs->win[BPB_FATSz16]);            /* Number of sectors per FAT */
    if (!fatsize) fatsize = LD_DWORD(&fs->win[BPB_FATSz32]);
    fs->sects_fat = fatsize;
    fs->n_fats = fs->win[BPB_NumFATs];                    /* Number of FAT copies */
    fatsize *= fs->n_fats;                                /* (Number of sectors in FAT area) */
    fs->fatbase = bootsect + LD_WORD(&fs->win[BPB_RsvdSecCnt]); /* FAT start sector (lba) */
    fs->sects_clust = fs->win[BPB_SecPerClus];            /* Number of sectors per cluster */
    fs->n_rootdir = LD_WORD(&fs->win[BPB_RootEntCnt]);    /* Nmuber of root directory entries */
    totalsect = LD_WORD(&fs->win[BPB_TotSec16]);        /* Number of sectors on the file system */
    if (!totalsect) totalsect = LD_DWORD(&fs->win[BPB_TotSec32]);
    fs->max_clust = maxclust = (totalsect                /* Last cluster# + 1 */
        - LD_WORD(&fs->win[BPB_RsvdSecCnt]) - fatsize - fs->n_rootdir / (S_SIZ/32)
        ) / fs->sects_clust + 2;

    fmt = FS_FAT12;                                        /* Determine the FAT sub type */
    if (maxclust > 0xFF7) fmt = FS_FAT16;
    if (maxclust > 0xFFF7) fmt = FS_FAT32;
    fs->fs_type = fmt;

    if (fmt == FS_FAT32)
        fs->dirbase = LD_DWORD(&fs->win[BPB_RootClus]);    /* Root directory start cluster */
    else
        fs->dirbase = fs->fatbase + fatsize;            /* Root directory start sector (lba) */
    fs->database = fs->fatbase + fatsize + fs->n_rootdir / (S_SIZ/32);    /* Data start sector (lba) */

#if !_FS_READONLY
    fs->free_clust = 0xFFFFFFFF;
#if _USE_FSINFO
    /* Load fsinfo sector if needed */
    if (fmt == FS_FAT32) {
        fs->fsi_sector = bootsect + LD_WORD(&fs->win[BPB_FSInfo]);
        if (disk_read(0, fs->win, fs->fsi_sector, 1) == RES_OK &&
            LD_WORD(&fs->win[BS_55AA]) == 0xAA55 &&
            LD_DWORD(&fs->win[FSI_LeadSig]) == 0x41615252 &&
            LD_DWORD(&fs->win[FSI_StrucSig]) == 0x61417272) {
            fs->last_clust = LD_DWORD(&fs->win[FSI_Nxt_Free]);
            fs->free_clust = LD_DWORD(&fs->win[FSI_Free_Count]);
        }
    }
#endif
#endif
    fs->id = ++fsid;                                    /* File system mount ID */
    return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* Check if the file/dir object is valid or not                          */
/*-----------------------------------------------------------------------*/

static
FRESULT validate (        /* FR_OK(0): The object is valid, !=0: Not valid */
    const FATFS *fs,    /* Pointer to the file system object */
    WORD id                /* id member of the target object to be checked */
)
{
    if (!fs || fs->id != id)
        return FR_INVALID_OBJECT;
    if (disk_status(fs->drive) & STA_NOINIT)
        return FR_NOT_READY;

    return FR_OK;
}




/*--------------------------------------------------------------------------

   Public Functions

--------------------------------------------------------------------------*/



/*-----------------------------------------------------------------------*/
/* Mount/Unmount a Locical Drive                                         */
/*-----------------------------------------------------------------------*/

FRESULT f_mount (
    BYTE drv,        /* Logical drive number to be mounted/unmounted */
    FATFS *fs        /* Pointer to new file system object (NULL for unmount)*/
)
{
    FATFS *fsobj;


    if (drv >= _DRIVES) return FR_INVALID_DRIVE;
    fsobj = FatFs[drv];
    FatFs[drv] = fs;
    if (fsobj) memset(fsobj, 0, sizeof(FATFS));
    if (fs) memset(fs, 0, sizeof(FATFS));

    return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* 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;


    fp->fs = NULL;
#if !_FS_READONLY
    mode &= (FA_READ|FA_WRITE|FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW);
    res = auto_mount(&path, &fs, (BYTE)(mode & (FA_WRITE|FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW)));
#else
    mode &= FA_READ;
    res = auto_mount(&path, &fs, 0);
#endif
    if (res != FR_OK) return res;
    dirobj.fs = fs;

    /* Trace the file path */
    res = trace_path(&dirobj, fn, path, &dir);
#if !_FS_READONLY
    /* Create or Open a file */
    if (mode & (FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW)) {
        DWORD ps, rs;
        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 with open name */
            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 it (R/O or DIR) */
                return FR_DENIED;
            if (mode & FA_CREATE_ALWAYS) {        /* Resize it to zero if needed */
                rs = ((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) | LD_WORD(&dir[DIR_FstClusLO]);    /* Get start cluster */
                ST_WORD(&dir[DIR_FstClusHI], 0);    /* cluster = 0 */
                ST_WORD(&dir[DIR_FstClusLO], 0);
                ST_DWORD(&dir[DIR_FileSize], 0);    /* size = 0 */
                fs->winflag = 1;
                ps = fs->winsect;                /* Remove the cluster chain */
                if (!remove_chain(fs, rs) || !move_window(fs, ps))
                    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 */
            ps = get_fattime();
            ST_DWORD(&dir[DIR_WrtTime], ps);    /* Updated time */
            ST_DWORD(&dir[DIR_CrtTime], ps);    /* Created time */
            fs->winflag = 1;
        }
    }
    /* Open an existing 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 */
        ((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) | 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 clust, sect, remain;
    WORD rcnt;
    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 & (S_SIZ - 1)) == 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(fs, fp->curr_clust);
                if (clust < 2 || clust >= fs->max_clust)
                    goto fr_error;
                fp->curr_clust = clust;                /* Current cluster */
                sect = clust2sect(fs, clust);        /* Get current sector */
                fp->sect_clust = fs->sects_clust;    /* Re-initialize the left sector counter */
            }
#if !_FS_READONLY
            if (fp->flag & FA__DIRTY) {                /* Flush file I/O buffer if needed */
                if (disk_write(fs->drive, fp->buffer, fp->curr_sect, 1) != RES_OK)
                    goto fr_error;
                fp->flag &= ~FA__DIRTY;
            }
#endif
            fp->curr_sect = sect;                    /* Update current sector */
            cc = btr / S_SIZ;                        /* When left bytes >= S_SIZ, */
            if (cc) {                                /* Read maximum contiguous sectors directly */
                if (cc > fp->sect_clust) cc = fp->sect_clust;
                if (disk_read(fs->drive, rbuff, sect, cc) != RES_OK)
                    goto fr_error;
                fp->sect_clust -= cc - 1;
                fp->curr_sect += cc - 1;
                rcnt = cc * S_SIZ; continue;
            }
            if (disk_read(fs->drive, fp->buffer, sect, 1) != RES_OK)    /* Load the sector into file I/O buffer */
                goto fr_error;
        }
        rcnt = S_SIZ - ((WORD)fp->fptr & (S_SIZ - 1));                /* Copy fractional bytes from file I/O buffer */
        if (rcnt > btr) rcnt = btr;
        memcpy(rbuff, &fp->buffer[fp->fptr & (S_SIZ - 1)], rcnt);
    }

    return FR_OK;

fr_error:    /* Abort this file 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 clust, sect;
    WORD wcnt;
    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 & (S_SIZ - 1)) == 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(fs, 0);    /* Create a new cluster chain */
                } else {                            /* Middle or end of file */
                    clust = create_chain(fs, 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(fs, clust);        /* Get current sector */
                fp->sect_clust = fs->sects_clust;    /* Re-initialize the left sector counter */
            }
            if (fp->flag & FA__DIRTY) {                /* Flush file I/O buffer if needed */
                if (disk_write(fs->drive, fp->buffer, fp->curr_sect, 1) != RES_OK)
                    goto fw_error;
                fp->flag &= ~FA__DIRTY;
            }
            fp->curr_sect = sect;                    /* Update current sector */
            cc = btw / S_SIZ;                        /* When left bytes >= S_SIZ, */
            if (cc) {                                /* Write maximum contiguous sectors directly */
                if (cc > fp->sect_clust) cc = fp->sect_clust;
                if (disk_write(fs->drive, wbuff, sect, cc) != RES_OK)
                    goto fw_error;
                fp->sect_clust -= cc - 1;
                fp->curr_sect += cc - 1;
                wcnt = cc * S_SIZ; continue;
            }
            if (fp->fptr < fp->fsize &&              /* Fill sector buffer with file data if needed */
                disk_read(fs->drive, fp->buffer, sect, 1) != RES_OK)
                    goto fw_error;
        }
        wcnt = S_SIZ - ((WORD)fp->fptr & (S_SIZ - 1));    /* Copy fractional bytes to file I/O buffer */
        if (wcnt > btw) wcnt = btw;
        memcpy(&fp->buffer[fp->fptr & (S_SIZ - 1)], wbuff, wcnt);
        fp->flag |= FA__DIRTY;
    }

    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 file 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? */
            /* Write back data buffer if needed */
            if (fp->flag & FA__DIRTY) {
                if (disk_write(fs->drive, fp->buffer, fp->curr_sect, 1) != RES_OK)
                    return FR_RW_ERROR;
                fp->flag &= ~FA__DIRTY;
            }
            /* Update the directory entry */
            if (!move_window(fs, 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 */
            ST_WORD(&dir[DIR_FstClusHI], fp->org_clust >> 16);
            tim = get_fattime();                    /* Updated time */
            ST_DWORD(&dir[DIR_WrtTime], tim);
            fp->flag &= ~FA__WRITTEN;
            res = sync(fs);
        }
    }
    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 R/W Pointer                                                 */
/*-----------------------------------------------------------------------*/

FRESULT f_lseek (
    FIL *fp,        /* Pointer to the file object */
    DWORD ofs        /* File pointer from top of file */
)
{
    DWORD clust, 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 (fp->flag & FA__DIRTY) {            /* Write-back dirty buffer if needed */
        if (disk_write(fs->drive, fp->buffer, fp->curr_sect, 1) != RES_OK)
            goto fk_error;
        fp->flag &= ~FA__DIRTY;
    }
    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(fs, 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 * S_SIZ;        /* 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(fs, clust);    /* Force streached if in write mode */
                else
#endif
                    clust = get_cluster(fs, 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) / S_SIZ);            /* Sector offset in the cluster */
            fp->curr_sect = clust2sect(fs, clust) + csect;    /* Current sector */
            if ((ofs & (S_SIZ - 1)) &&                    /* Load current sector if needed */
                disk_read(fs->drive, fp->buffer, fp->curr_sect, 1) != RES_OK)
                goto fk_error;
            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 file due to an unrecoverable error */
    fp->flag |= FA__ERROR;
    return FR_RW_ERROR;
}




#if _FS_MINIMIZE <= 1
/*-----------------------------------------------------------------------*/
/* Create a directroy object                                             */
/*-----------------------------------------------------------------------*/

FRESULT f_opendir (
    DIR *dirobj,        /* Pointer to directory object to create */
    const char *path    /* Pointer to the directory path */
)
{
    BYTE *dir;
    char fn[8+3+1];
    FRESULT res;
    FATFS *fs;


    res = auto_mount(&path, &fs, 0);
    if (res != FR_OK) return res;
    dirobj->fs = fs;

    res = trace_path(dirobj, fn, path, &dir);    /* Trace the directory path */
    if (res == FR_OK) {                        /* Trace completed */
        if (dir != NULL) {                    /* It is not the root dir */
            if (dir[DIR_Attr] & AM_DIR) {        /* The entry is a directory */
                dirobj->clust = ((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) | LD_WORD(&dir[DIR_FstClusLO]);
                dirobj->sect = clust2sect(fs, dirobj->clust);
                dirobj->index = 2;
            } else {                        /* The entry is not a directory */
                res = FR_NO_FILE;
            }
        }
        dirobj->id = fs->id;
    }
    return res;
}




/*-----------------------------------------------------------------------*/
/* Read Directory Entry in Sequense                                      */
/*-----------------------------------------------------------------------*/

FRESULT f_readdir (
    DIR *dirobj,        /* Pointer to the directory object */
    FILINFO *finfo        /* Pointer to file information to return */
)
{
    BYTE *dir, c, res;
    FATFS *fs = dirobj->fs;


    res = validate(fs, dirobj->id);            /* Check validity of the object */
    if (res) return res;

    finfo->fname[0] = 0;
    while (dirobj->sect) {
        if (!move_window(fs, dirobj->sect))
            return FR_RW_ERROR;
        dir = &fs->win[(dirobj->index & ((S_SIZ - 1) >> 5)) * 32];    /* pointer to the directory entry */
        c = *dir;
        if (c == 0) break;                                /* Has it reached to end of dir? */
        if (c != 0xE5 && !(dir[DIR_Attr] & AM_VOL))        /* Is it a valid entry? */
            get_fileinfo(finfo, dir);
        if (!next_dir_entry(dirobj)) dirobj->sect = 0;    /* Next entry */
        if (finfo->fname[0]) break;                        /* Found valid entry */
    }

    return FR_OK;
}




#if _FS_MINIMIZE == 0
/*-----------------------------------------------------------------------*/
/* Get File Status                                                       */
/*-----------------------------------------------------------------------*/

FRESULT f_stat (
    const char *path,    /* Pointer to the file path */
    FILINFO *finfo        /* Pointer to file information to return */
)
{
    BYTE *dir;
    char fn[8+3+1];
    FRESULT res;
    DIR dirobj;
    FATFS *fs;


    res = auto_mount(&path, &fs, 0);
    if (res != FR_OK) return res;
    dirobj.fs = fs;

    res = trace_path(&dirobj, fn, path, &dir);    /* Trace the file path */
    if (res == FR_OK) {                            /* Trace completed */
        if (dir)    /* Found an object */
            get_fileinfo(finfo, dir);
        else        /* It is root dir */
            res = FR_INVALID_NAME;
    }

    return res;
}



#if !_FS_READONLY
/*-----------------------------------------------------------------------*/
/* Get Number of Free Clusters                                           */
/*-----------------------------------------------------------------------*/

FRESULT f_getfree (
    const char *drv,    /* Logical drive number */
    DWORD *nclust,        /* Pointer to the double word to return number of free clusters */
    FATFS **fatfs        /* Pointer to pointer to the file system object to return */
)
{
    DWORD n, clust, sect;
    BYTE fat, f, *p;
    FRESULT res;
    FATFS *fs;


    /* Get drive number */
    res = auto_mount(&drv, &fs, 0);
    if (res != FR_OK) return res;
    *fatfs = fs;

    /* If number of free cluster is valid, return it without cluster scan. */
    if (fs->free_clust <= fs->max_clust - 2) {
        *nclust = fs->free_clust;
        return FR_OK;
    }

    /* Count number of free clusters */
    fat = fs->fs_type;
    n = 0;
    if (fat == FS_FAT12) {
        clust = 2;
        do {
            if ((WORD)get_cluster(fs, clust) == 0) n++;
        } while (++clust < fs->max_clust);
    } else {
        clust = fs->max_clust;
        sect = fs->fatbase;
        f = 0; p = 0;
        do {
            if (!f) {
                if (!move_window(fs, sect++)) return FR_RW_ERROR;
                p = fs->win;
            }
            if (fat == FS_FAT16) {
                if (LD_WORD(p) == 0) n++;
                p += 2; f += 1;
            } else {
                if (LD_DWORD(p) == 0) n++;
                p += 4; f += 2;
            }
        } while (--clust);
    }
    fs->free_clust = n;
#if _USE_FSINFO
    if (fat == FS_FAT32) fs->fsi_flag = 1;
#endif

    *nclust = n;
    return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* Delete a File or a Directory                                          */
/*-----------------------------------------------------------------------*/

FRESULT f_unlink (
    const char *path            /* Pointer to the file or directory path */
)
{
    BYTE *dir, *sdir;
    DWORD dclust, dsect;
    char fn[8+3+1];
    FRESULT res;
    DIR dirobj;
    FATFS *fs;


    res = auto_mount(&path, &fs, 1);
    if (res != FR_OK) return res;
    dirobj.fs = fs;

    res = trace_path(&dirobj, fn, path, &dir);    /* Trace the file path */
    if (res != FR_OK) return res;                /* Trace failed */
    if (dir == NULL) return FR_INVALID_NAME;    /* It is the root directory */
    if (dir[DIR_Attr] & AM_RDO) return FR_DENIED;    /* It is a R/O object */
    dsect = fs->winsect;
    dclust = ((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) | LD_WORD(&dir[DIR_FstClusLO]);

    if (dir[DIR_Attr] & AM_DIR) {                /* It is a sub-directory */
        dirobj.clust = dclust;                    /* Check if the sub-dir is empty or not */
        dirobj.sect = clust2sect(fs, dclust);
        dirobj.index = 2;
        do {
            if (!move_window(fs, dirobj.sect)) return FR_RW_ERROR;
            sdir = &fs->win[(dirobj.index & ((S_SIZ - 1) >> 5)) * 32];
            if (sdir[DIR_Name] == 0) break;
            if (sdir[DIR_Name] != 0xE5 && !(sdir[DIR_Attr] & AM_VOL))
                return FR_DENIED;    /* The directory is not empty */
        } while (next_dir_entry(&dirobj));
    }

    if (!move_window(fs, dsect)) return FR_RW_ERROR;    /* Mark the directory entry 'deleted' */
    dir[DIR_Name] = 0xE5;
    fs->winflag = 1;
    if (!remove_chain(fs, dclust)) return FR_RW_ERROR;    /* Remove the cluster chain */

    return sync(fs);
}




/*-----------------------------------------------------------------------*/
/* Create a Directory                                                    */
/*-----------------------------------------------------------------------*/

FRESULT f_mkdir (
    const char *path        /* Pointer to the directory path */
)
{
    BYTE *dir, *fw, n;
    char fn[8+3+1];
    DWORD sect, dsect, dclust, pclust, tim;
    FRESULT res;
    DIR dirobj;
    FATFS *fs;


    res = auto_mount(&path, &fs, 1);
    if (res != FR_OK) return res;
    dirobj.fs = fs;

    res = trace_path(&dirobj, fn, path, &dir);    /* Trace the file path */
    if (res == FR_OK) return FR_EXIST;            /* Any file or directory is already existing */
    if (res != FR_NO_FILE) return res;

    res = reserve_direntry(&dirobj, &dir);         /* Reserve a directory entry */
    if (res != FR_OK) return res;
    sect = fs->winsect;
    dclust = create_chain(fs, 0);                /* Allocate a cluster for new directory table */
    if (dclust == 1) return FR_RW_ERROR;
    dsect = clust2sect(fs, dclust);
    if (!dsect) return FR_DENIED;
    if (!move_window(fs, dsect)) return FR_RW_ERROR;

    fw = fs->win;
    memset(fw, 0, S_SIZ);                        /* Clear the new directory table */
    for (n = 1; n < fs->sects_clust; n++) {
        if (disk_write(fs->drive, fw, ++dsect, 1) != RES_OK)
            return FR_RW_ERROR;
    }
    memset(&fw[DIR_Name], ' ', 8+3);            /* Create "." entry */
    fw[DIR_Name] = '.';
    fw[DIR_Attr] = AM_DIR;
    tim = get_fattime();
    ST_DWORD(&fw[DIR_WrtTime], tim);
    memcpy(&fw[32], &fw[0], 32); fw[33] = '.';    /* Create ".." entry */
    pclust = dirobj.sclust;
#if _FAT32
    ST_WORD(&fw[   DIR_FstClusHI], dclust >> 16);
    if (fs->fs_type == FS_FAT32 && pclust == fs->dirbase) pclust = 0;
    ST_WORD(&fw[32+DIR_FstClusHI], pclust >> 16);
#endif
    ST_WORD(&fw[   DIR_FstClusLO], dclust);
    ST_WORD(&fw[32+DIR_FstClusLO], pclust);
    fs->winflag = 1;

    if (!move_window(fs, sect)) return FR_RW_ERROR;
    memset(&dir[0], 0, 32);                        /* Initialize the new entry */
    memcpy(&dir[DIR_Name], fn, 8+3);            /* Name */
    dir[DIR_NTres] = fn[11];
    dir[DIR_Attr] = AM_DIR;                        /* Attribute */
    ST_DWORD(&dir[DIR_WrtTime], tim);            /* Crated time */
    ST_WORD(&dir[DIR_FstClusLO], dclust);        /* Table start cluster */
    ST_WORD(&dir[DIR_FstClusHI], dclust >> 16);

    return sync(fs);
}




/*-----------------------------------------------------------------------*/
/* Change File Attribute                                                 */
/*-----------------------------------------------------------------------*/

FRESULT f_chmod (
    const char *path,    /* Pointer to the file path */
    BYTE value,            /* Attribute bits */
    BYTE mask            /* Attribute mask to change */
)
{
    FRESULT res;
    BYTE *dir;
    DIR dirobj;
    char fn[8+3+1];
    FATFS *fs;


    res = auto_mount(&path, &fs, 1);
    if (res == FR_OK) {
        dirobj.fs = fs;
        res = trace_path(&dirobj, fn, path, &dir);    /* Trace the file path */
        if (res == FR_OK) {            /* Trace completed */
            if (dir == NULL) {
                res = FR_INVALID_NAME;
            } else {
                mask &= AM_RDO|AM_HID|AM_SYS|AM_ARC;    /* Valid attribute mask */
                dir[DIR_Attr] = (value & mask) | (dir[DIR_Attr] & (BYTE)~mask);    /* Apply attribute change */
                res = sync(fs);
            }
        }
    }
    return res;
}




/*-----------------------------------------------------------------------*/
/* Rename File/Directory                                                 */
/*-----------------------------------------------------------------------*/

FRESULT f_rename (
    const char *path_old,    /* Pointer to the old name */
    const char *path_new    /* Pointer to the new name */
)
{
    FRESULT res;
    DWORD sect_old;
    BYTE *dir_old, *dir_new, direntry[32-11];
    DIR dirobj;
    char fn[8+3+1];
    FATFS *fs;


    res = auto_mount(&path_old, &fs, 1);
    if (res != FR_OK) return res;
    dirobj.fs = fs;

    res = trace_path(&dirobj, fn, path_old, &dir_old);    /* Check old object */
    if (res != FR_OK) return res;            /* The old object is not found */
    if (!dir_old) return FR_NO_FILE;
    sect_old = fs->winsect;                    /* Save the object information */
    memcpy(direntry, &dir_old[DIR_Attr], 32-11);

    res = trace_path(&dirobj, fn, path_new, &dir_new);    /* Check new object */
    if (res == FR_OK) return FR_EXIST;            /* The new object name is already existing */
    if (res != FR_NO_FILE) return res;            /* Is there no old name? */
    res = reserve_direntry(&dirobj, &dir_new);     /* Reserve a directory entry */
    if (res != FR_OK) return res;

    memcpy(&dir_new[DIR_Attr], direntry, 32-11);    /* Create new entry */
    memcpy(&dir_new[DIR_Name], fn, 8+3);
    dir_new[DIR_NTres] = fn[11];
    fs->winflag = 1;

    if (!move_window(fs, sect_old)) return FR_RW_ERROR;    /* Remove old entry */
    dir_old[DIR_Name] = 0xE5;

    return sync(fs);
}



#if _USE_MKFS
/*-----------------------------------------------------------------------*/
/* Create File System on the Drive                                       */
/*-----------------------------------------------------------------------*/

#define N_ROOTDIR 512
#define N_FATS 1
#define MAX_SECTOR 64000000UL
#define MIN_SECTOR 2000UL
#define ERASE_BLK 32


FRESULT f_mkfs (
    BYTE drv,            /* Logical drive number */
    BYTE partition,        /* Partitioning rule 0:FDISK, 1:SFD */
    BYTE allocsize        /* Allocation unit size [sectors] */
)
{
    BYTE fmt, m, *tbl;
    DWORD b_part, b_fat, b_dir, b_data;        /* Area offset (LBA) */
    DWORD n_part, n_rsv, n_fat, n_dir;        /* Area size */
    DWORD n_clust, n;
    FATFS *fs;
    DSTATUS stat;


    /* Check and mounted drive and clear work area */
    if (drv >= _DRIVES) return FR_INVALID_DRIVE;
    fs = FatFs[drv];
    if (!fs) return FR_NOT_ENABLED;
    memset(fs, 0, sizeof(FATFS));
    drv = LD2PD(drv);

    /* Check validity of the parameters */
    for (n = 1; n <= 64 && allocsize != n; n <<= 1);
    if (n > 64 || partition >= 2) return FR_MKFS_ABORTED;

    /* Get disk statics */
    stat = disk_initialize(drv);
    if (stat & STA_NOINIT) return FR_NOT_READY;
    if (stat & STA_PROTECT) return FR_WRITE_PROTECTED;
    if (disk_ioctl(drv, GET_SECTOR_COUNT, &n_part) != RES_OK || n_part < MIN_SECTOR)
        return FR_MKFS_ABORTED;
    if (n_part > MAX_SECTOR) n_part = MAX_SECTOR;
    b_part = (!partition) ? 63 : 0;
    n_part -= b_part;
#if S_MAX_SIZ > 512                        /* Check disk sector size */
    if (disk_ioctl(drv, GET_SECTOR_SIZE, &S_SIZ) != RES_OK
        || S_SIZ > S_MAX_SIZ
        || (DWORD)S_SIZ * allocsize > 32768U)
        return FR_MKFS_ABORTED;
#endif

    /* Pre-compute number of clusters and FAT type */
    n_clust = n_part / allocsize;
    fmt = FS_FAT12;
    if (n_clust >= 0xFF7) fmt = FS_FAT16;
    if (n_clust >= 0xFFF7) fmt = FS_FAT32;
    switch (fmt) {
    case FS_FAT12:
        n_fat = ((n_clust * 3 + 1) / 2 + 3 + S_SIZ - 1) / S_SIZ;
        n_rsv = 1 + partition;
        n_dir = N_ROOTDIR * 32 / S_SIZ;
        break;
    case FS_FAT16:
        n_fat = ((n_clust * 2) + 4 + S_SIZ - 1) / S_SIZ;
        n_rsv = 1 + partition;
        n_dir = N_ROOTDIR * 32 / S_SIZ;
        break;
    default:
        n_fat = ((n_clust * 4) + 8 + S_SIZ - 1) / S_SIZ;
        n_rsv = 33 - partition;
        n_dir = 0;
    }
    b_fat = b_part + n_rsv;            /* FATs start sector */
    b_dir = b_fat + n_fat * N_FATS;    /* Directory start sector */
    b_data = b_dir + n_dir;            /* Data start sector */

#ifdef ERASE_BLK
    /* Round up data start sector to erase block boundary */
    n = (b_data + ERASE_BLK - 1) & ~(ERASE_BLK - 1);
    b_dir += n - b_data;
    n_fat += (n - b_data) / N_FATS;
#endif
    /* Determine number of cluster and final check of validity of the FAT type */
    n_clust = (n_part - n_rsv - n_fat * 2 - n_dir) / allocsize;
    if (   (fmt == FS_FAT16 && n_clust < 0xFF7)
        || (fmt == FS_FAT32 && n_clust < 0xFFF7))
        return FR_MKFS_ABORTED;

    /* Create partition table if needed */
    if (!partition) {
        DWORD n_disk = b_part + n_part;

        tbl = &fs->win[MBR_Table];
        ST_DWORD(&tbl[0], 0x00010180);    /* Partition start in CHS */
        if (n_disk < 63UL * 255 * 1024) {    /* Partition end in CHS */
            n_disk = n_disk / 63 / 255;
            tbl[7] = (BYTE)n_disk;
            tbl[6] = (BYTE)((n_disk >> 2) | 63);
        } else {
            ST_WORD(&tbl[6], 0xFFFF);
        }
        tbl[5] = 254;
        if (fmt != FS_FAT32)            /* System ID */
            tbl[4] = (n_part < 0x10000) ? 0x04 : 0x06;
        else
            tbl[4] = 0x0c;
        ST_DWORD(&tbl[8], 63);            /* Partition start in LBA */
        ST_DWORD(&tbl[12], n_part);        /* Partition size in LBA */
        ST_WORD(&tbl[64], 0xAA55);        /* Signature */
        if (disk_write(drv, fs->win, 0, 1) != RES_OK)
            return FR_RW_ERROR;
    }

    /* Create boot record */
    memset(tbl = fs->win, 0, S_SIZ);
    ST_DWORD(&tbl[BS_jmpBoot], 0x90FEEB);        /* Boot code (jmp $, nop) */
    ST_WORD(&tbl[BPB_BytsPerSec], S_SIZ);        /* Sector size */
    tbl[BPB_SecPerClus] = (BYTE)allocsize;        /* Sectors per cluster */
    ST_WORD(&tbl[BPB_RsvdSecCnt], n_rsv);        /* Reserved sectors */
    tbl[BPB_NumFATs] = N_FATS;                    /* Number of FATs */
    ST_WORD(&tbl[BPB_RootEntCnt], S_SIZ / 32 * n_dir); /* Number of rootdir entries */
    if (n_part < 0x10000) {                        /* Number of total sectors */
        ST_WORD(&tbl[BPB_TotSec16], n_part);
    } else {
        ST_DWORD(&tbl[BPB_TotSec32], n_part);
    }
    tbl[BPB_Media] = 0xF8;                        /* Media descripter */
    ST_WORD(&tbl[BPB_SecPerTrk], 63);            /* Number of sectors per track */
    ST_WORD(&tbl[BPB_NumHeads], 255);            /* Number of heads */
    ST_DWORD(&tbl[BPB_HiddSec], b_part);        /* Hidden sectors */
    if (fmt != FS_FAT32) {
        ST_WORD(&tbl[BPB_FATSz16], n_fat);        /* Number of secters per FAT */
        tbl[BS_DrvNum] = 0x80;                    /* Drive number */
        tbl[BS_BootSig] = 0x29;                    /* Extended boot signature */
        memcpy(&tbl[BS_VolLab], "NO NAME    FAT     ", 19);    /* Volume lavel, FAT signature */
    } else {
        ST_DWORD(&tbl[BPB_FATSz32], n_fat);        /* Number of secters per FAT */
        ST_DWORD(&tbl[BPB_RootClus], 2);        /* Root directory cluster (2) */
        ST_WORD(&tbl[BPB_FSInfo], 1);            /* FSInfo record (bs+1) */
        ST_WORD(&tbl[BPB_BkBootSec], 6);        /* Backup boot record (bs+6) */
        tbl[BS_DrvNum32] = 0x80;                /* Drive number */
        tbl[BS_BootSig32] = 0x29;                /* Extended boot signature */
        memcpy(&tbl[BS_VolLab32], "NO NAME    FAT32   ", 19);    /* Volume lavel, FAT signature */
    }
    ST_WORD(&tbl[BS_55AA], 0xAA55);            /* Signature */
    if (disk_write(drv, tbl, b_part+0, 1) != RES_OK)
        return FR_RW_ERROR;
    if (fmt == FS_FAT32)
        disk_write(drv, tbl, b_part+6, 1);

    /* Initialize FAT area */
    for (m = 0; m < N_FATS; m++) {
        memset(tbl, 0, S_SIZ);        /* 1st sector of the FAT  */
        if (fmt != FS_FAT32) {
            n = (fmt == FS_FAT12) ? 0x00FFFFF8 : 0xFFFFFFF8;
            ST_DWORD(&tbl[0], n);            /* Reserve cluster #0-1 (FAT12/16) */
        } else {
            ST_DWORD(&tbl[0], 0xFFFFFFF8);    /* Reserve cluster #0-1 (FAT32) */
            ST_DWORD(&tbl[4], 0xFFFFFFFF);
            ST_DWORD(&tbl[8], 0x0FFFFFFF);    /* Reserve cluster #2 for root dir */
        }
        if (disk_write(drv, tbl, b_fat++, 1) != RES_OK)
            return FR_RW_ERROR;
        memset(tbl, 0, S_SIZ);        /* Following FAT entries are filled by zero */
        for (n = 1; n < n_fat; n++) {
            if (disk_write(drv, tbl, b_fat++, 1) != RES_OK)
                return FR_RW_ERROR;
        }
    }

    /* Initialize Root directory */
    for (m = 0; m < 64; m++) {
        if (disk_write(drv, tbl, b_fat++, 1) != RES_OK)
            return FR_RW_ERROR;
    }

    /* Create FSInfo record if needed */
    if (fmt == FS_FAT32) {
        ST_WORD(&tbl[BS_55AA], 0xAA55);
        ST_DWORD(&tbl[FSI_LeadSig], 0x41615252);
        ST_DWORD(&tbl[FSI_StrucSig], 0x61417272);
        ST_DWORD(&tbl[FSI_Free_Count], n_clust - 1);
        ST_DWORD(&tbl[FSI_Nxt_Free], 0xFFFFFFFF);
        disk_write(drv, tbl, b_part+1, 1);
        disk_write(drv, tbl, b_part+7, 1);
    }

    return (disk_ioctl(drv, CTRL_SYNC, NULL) == RES_OK) ? FR_OK : FR_RW_ERROR;
}

#endif /* _USE_MKFS */
#endif /* !_FS_READONLY */
#endif /* _FS_MINIMIZE == 0 */
#endif /* _FS_MINIMIZE <= 1 */
#endif /* _FS_MINIMIZE <= 2 */



