//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
//                            FAT16/32 File IO Library
//                                    V2.6
//                              Ultra-Embedded.com
//                            Copyright 2003 - 2012
//
//                         Email: admin@ultra-embedded.com
//
//                                License: GPL
//   If you would like a version with a more permissive license for use in
//   closed source commercial applications please contact me for details.
//-----------------------------------------------------------------------------
//
// This file is part of FAT File IO Library.
//
// FAT File IO Library 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 2 of the License, or
// (at your option) any later version.
//
// FAT File IO Library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// 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 FAT File IO Library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
#include <string.h>
#include "fat_defs.h"
#include "fat_access.h"
#include "fat_table.h"
#include "fat_write.h"
#include "fat_string.h"
#include "fat_misc.h"

//-----------------------------------------------------------------------------
// fatfs_init: Load FAT Parameters
//-----------------------------------------------------------------------------
int fatfs_init(struct fatfs *fs)
{
    uint8 num_of_fats;
    uint16 reserved_sectors;
    uint32 FATSz;
    uint32 root_dir_sectors;
    uint32 total_sectors;
    uint32 data_sectors;
    uint32 count_of_clusters;
    uint8 valid_partition = 0;

    fs->currentsector.address = FAT32_INVALID_CLUSTER;
    fs->currentsector.dirty = 0;

    fs->next_free_cluster = 0; // Invalid

    fatfs_fat_init(fs);

    // Make sure we have a read function (write function is optional)
    if (!fs->disk_io.read_media)
        return FAT_INIT_MEDIA_ACCESS_ERROR;

    // MBR: Sector 0 on the disk
    // NOTE: Some removeable media does not have this.

    // Load MBR (LBA 0) into the 512 byte buffer
    if (!fs->disk_io.read_media(0, fs->currentsector.sector, 1))
        return FAT_INIT_MEDIA_ACCESS_ERROR;

    // Make Sure 0x55 and 0xAA are at end of sector
    // (this should be the case regardless of the MBR or boot sector)
    if (fs->currentsector.sector[SIGNATURE_POSITION] != 0x55 || fs->currentsector.sector[SIGNATURE_POSITION+1] != 0xAA)
        return FAT_INIT_INVALID_SIGNATURE;

    // Now check again using the access function to prove endian conversion function
    if (GET_16BIT_WORD(fs->currentsector.sector, SIGNATURE_POSITION) != SIGNATURE_VALUE)
        return FAT_INIT_ENDIAN_ERROR;

    // Verify packed structures
    if (sizeof(struct fat_dir_entry) != FAT_DIR_ENTRY_SIZE)
        return FAT_INIT_STRUCT_PACKING;

    // Check the partition type code
    switch(fs->currentsector.sector[PARTITION1_TYPECODE_LOCATION])
    {
        case 0x0B:
        case 0x06:
        case 0x0C:
        case 0x0E:
        case 0x0F:
        case 0x05:
            valid_partition = 1;
        break;
        case 0x00:
            valid_partition = 0;
            break;
        default:
            if (fs->currentsector.sector[PARTITION1_TYPECODE_LOCATION] <= 0x06)
                valid_partition = 1;
        break;
    }

    // Read LBA Begin for the file system
    if (valid_partition)
        fs->lba_begin = GET_32BIT_WORD(fs->currentsector.sector, PARTITION1_LBA_BEGIN_LOCATION);
    // Else possibly MBR less disk
    else
        fs->lba_begin = 0;

    // Load Volume 1 table into sector buffer
    // (We may already have this in the buffer if MBR less drive!)
    if (!fs->disk_io.read_media(fs->lba_begin, fs->currentsector.sector, 1))
        return FAT_INIT_MEDIA_ACCESS_ERROR;

    // Make sure there are 512 bytes per cluster
    if (GET_16BIT_WORD(fs->currentsector.sector, 0x0B) != FAT_SECTOR_SIZE)
        return FAT_INIT_INVALID_SECTOR_SIZE;

    // Load Parameters of FAT partition
    fs->sectors_per_cluster = fs->currentsector.sector[BPB_SECPERCLUS];
    reserved_sectors = GET_16BIT_WORD(fs->currentsector.sector, BPB_RSVDSECCNT);
    num_of_fats = fs->currentsector.sector[BPB_NUMFATS];
    fs->root_entry_count = GET_16BIT_WORD(fs->currentsector.sector, BPB_ROOTENTCNT);

    if(GET_16BIT_WORD(fs->currentsector.sector, BPB_FATSZ16) != 0)
        fs->fat_sectors = GET_16BIT_WORD(fs->currentsector.sector, BPB_FATSZ16);
    else
        fs->fat_sectors = GET_32BIT_WORD(fs->currentsector.sector, BPB_FAT32_FATSZ32);

    // For FAT32 (which this may be)
    fs->rootdir_first_cluster = GET_32BIT_WORD(fs->currentsector.sector, BPB_FAT32_ROOTCLUS);
    fs->fs_info_sector = GET_16BIT_WORD(fs->currentsector.sector, BPB_FAT32_FSINFO);

    // For FAT16 (which this may be), rootdir_first_cluster is actuall rootdir_first_sector
    fs->rootdir_first_sector = reserved_sectors + (num_of_fats * fs->fat_sectors);
    fs->rootdir_sectors = ((fs->root_entry_count * 32) + (FAT_SECTOR_SIZE - 1)) / FAT_SECTOR_SIZE;

    // First FAT LBA address
    fs->fat_begin_lba = fs->lba_begin + reserved_sectors;

    // The address of the first data cluster on this volume
    fs->cluster_begin_lba = fs->fat_begin_lba + (num_of_fats * fs->fat_sectors);

    if (GET_16BIT_WORD(fs->currentsector.sector, 0x1FE) != 0xAA55) // This signature should be AA55
        return FAT_INIT_INVALID_SIGNATURE;

    // Calculate the root dir sectors
    root_dir_sectors = ((GET_16BIT_WORD(fs->currentsector.sector, BPB_ROOTENTCNT) * 32) + (GET_16BIT_WORD(fs->currentsector.sector, BPB_BYTSPERSEC) - 1)) / GET_16BIT_WORD(fs->currentsector.sector, BPB_BYTSPERSEC);

    if(GET_16BIT_WORD(fs->currentsector.sector, BPB_FATSZ16) != 0)
        FATSz = GET_16BIT_WORD(fs->currentsector.sector, BPB_FATSZ16);
    else
        FATSz = GET_32BIT_WORD(fs->currentsector.sector, BPB_FAT32_FATSZ32);

    if(GET_16BIT_WORD(fs->currentsector.sector, BPB_TOTSEC16) != 0)
        total_sectors = GET_16BIT_WORD(fs->currentsector.sector, BPB_TOTSEC16);
    else
        total_sectors = GET_32BIT_WORD(fs->currentsector.sector, BPB_TOTSEC32);

    data_sectors = total_sectors - (GET_16BIT_WORD(fs->currentsector.sector, BPB_RSVDSECCNT) + (fs->currentsector.sector[BPB_NUMFATS] * FATSz) + root_dir_sectors);

    // Find out which version of FAT this is...
    if (fs->sectors_per_cluster != 0)
    {
        count_of_clusters = data_sectors / fs->sectors_per_cluster;

        if(count_of_clusters < 4085)
            // Volume is FAT12
            return FAT_INIT_WRONG_FILESYS_TYPE;
        else if(count_of_clusters < 65525)
        {
            // Clear this FAT32 specific param
            fs->rootdir_first_cluster = 0;

            // Volume is FAT16
            fs->fat_type = FAT_TYPE_16;
            return FAT_INIT_OK;
        }
        else
        {
            // Volume is FAT32
            fs->fat_type = FAT_TYPE_32;
            return FAT_INIT_OK;
        }
    }
    else
        return FAT_INIT_WRONG_FILESYS_TYPE;
}
//-----------------------------------------------------------------------------
// fatfs_lba_of_cluster: This function converts a cluster number into a sector /
// LBA number.
//-----------------------------------------------------------------------------
uint32 fatfs_lba_of_cluster(struct fatfs *fs, uint32 Cluster_Number)
{
    if (fs->fat_type == FAT_TYPE_16)
        return (fs->cluster_begin_lba + (fs->root_entry_count * 32 / FAT_SECTOR_SIZE) + ((Cluster_Number-2) * fs->sectors_per_cluster));
    else
        return ((fs->cluster_begin_lba + ((Cluster_Number-2)*fs->sectors_per_cluster)));
}
//-----------------------------------------------------------------------------
// fatfs_sector_read:
//-----------------------------------------------------------------------------
int fatfs_sector_read(struct fatfs *fs, uint32 lba, uint8 *target, uint32 count)
{
    return fs->disk_io.read_media(lba, target, count);
}
//-----------------------------------------------------------------------------
// fatfs_sector_write:
//-----------------------------------------------------------------------------
int fatfs_sector_write(struct fatfs *fs, uint32 lba, uint8 *target, uint32 count)
{
    return fs->disk_io.write_media(lba, target, count);
}
//-----------------------------------------------------------------------------
// fatfs_sector_reader: From the provided startcluster and sector offset
// Returns True if success, returns False if not (including if read out of range)
//-----------------------------------------------------------------------------
int fatfs_sector_reader(struct fatfs *fs, uint32 start_cluster, uint32 offset, uint8 *target)
{
    uint32 sector_to_read = 0;
    uint32 cluster_to_read = 0;
    uint32 cluster_chain = 0;
    uint32 i;
    uint32 lba;

    // FAT16 Root directory
    if (fs->fat_type == FAT_TYPE_16 && start_cluster == 0)
    {
        if (offset < fs->rootdir_sectors)
            lba = fs->lba_begin + fs->rootdir_first_sector + offset;
        else
            return 0;
    }
    // FAT16/32 Other
    else
    {
        // Set start of cluster chain to initial value
        cluster_chain = start_cluster;

        // Find parameters
        cluster_to_read = offset / fs->sectors_per_cluster;
        sector_to_read = offset - (cluster_to_read*fs->sectors_per_cluster);

        // Follow chain to find cluster to read
        for (i=0; i<cluster_to_read; i++)
            cluster_chain = fatfs_find_next_cluster(fs, cluster_chain);

        // If end of cluster chain then return false
        if (cluster_chain == FAT32_LAST_CLUSTER)
            return 0;

        // Calculate sector address
        lba = fatfs_lba_of_cluster(fs, cluster_chain)+sector_to_read;
    }

    // User provided target array
    if (target)
        return fs->disk_io.read_media(lba, target, 1);
    // Else read sector if not already loaded
    else if (lba != fs->currentsector.address)
    {
        fs->currentsector.address = lba;
        return fs->disk_io.read_media(fs->currentsector.address, fs->currentsector.sector, 1);
    }
    else
        return 1;
}
//-----------------------------------------------------------------------------
// fatfs_read_sector: Read from the provided cluster and sector offset
// Returns True if success, returns False if not
//-----------------------------------------------------------------------------
int fatfs_read_sector(struct fatfs *fs, uint32 cluster, uint32 sector, uint8 *target)
{
    // FAT16 Root directory
    if (fs->fat_type == FAT_TYPE_16 && cluster == 0)
    {
        uint32 lba;

        // In FAT16, there are a limited amount of sectors in root dir!
        if (sector < fs->rootdir_sectors)
            lba = fs->lba_begin + fs->rootdir_first_sector + sector;
        else
            return 0;

        // User target buffer passed in
        if (target)
        {
            // Read from disk
            return fs->disk_io.read_media(lba, target, 1);
        }
        else
        {
            // Calculate read address
            fs->currentsector.address = lba;

            // Read from disk
            return fs->disk_io.read_media(fs->currentsector.address, fs->currentsector.sector, 1);
        }
    }
    // FAT16/32 Other
    else
    {
        // User target buffer passed in
        if (target)
        {
            // Calculate read address
            uint32 lba = fatfs_lba_of_cluster(fs, cluster) + sector;

            // Read from disk
            return fs->disk_io.read_media(lba, target, 1);
        }
        else
        {
            // Calculate write address
            fs->currentsector.address = fatfs_lba_of_cluster(fs, cluster)+sector;

            // Read from disk
            return fs->disk_io.read_media(fs->currentsector.address, fs->currentsector.sector, 1);
        }
    }
}
//-----------------------------------------------------------------------------
// fatfs_write_sector: Write to the provided cluster and sector offset
// Returns True if success, returns False if not
//-----------------------------------------------------------------------------
#if FATFS_INC_WRITE_SUPPORT
int fatfs_write_sector(struct fatfs *fs, uint32 cluster, uint32 sector, uint8 *target)
{
    // No write access?
    if (!fs->disk_io.write_media)
        return 0;

    // FAT16 Root directory
    if (fs->fat_type == FAT_TYPE_16 && cluster == 0)
    {
        uint32 lba;

        // In FAT16 we cannot extend the root dir!
        if (sector < fs->rootdir_sectors)
            lba = fs->lba_begin + fs->rootdir_first_sector + sector;
        else
            return 0;

        // User target buffer passed in
        if (target)
        {
            // Write to disk
            return fs->disk_io.write_media(lba, target, 1);
        }
        else
        {
            // Calculate write address
            fs->currentsector.address = lba;

            // Write to disk
            return fs->disk_io.write_media(fs->currentsector.address, fs->currentsector.sector, 1);
        }
    }
    // FAT16/32 Other
    else
    {
        // User target buffer passed in
        if (target)
        {
            // Calculate write address
            uint32 lba = fatfs_lba_of_cluster(fs, cluster) + sector;

            // Write to disk
            return fs->disk_io.write_media(lba, target, 1);
        }
        else
        {
            // Calculate write address
            fs->currentsector.address = fatfs_lba_of_cluster(fs, cluster)+sector;

            // Write to disk
            return fs->disk_io.write_media(fs->currentsector.address, fs->currentsector.sector, 1);
        }
    }
}
#endif
//-----------------------------------------------------------------------------
// fatfs_show_details: Show the details about the filesystem
//-----------------------------------------------------------------------------
void fatfs_show_details(struct fatfs *fs)
{
    FAT_PRINTF(("FAT details:\r\n"));
    FAT_PRINTF((" Type =%s", (fs->fat_type == FAT_TYPE_32) ? "FAT32": "FAT16"));
    FAT_PRINTF((" Root Dir First Cluster = %x\r\n", fs->rootdir_first_cluster));
    FAT_PRINTF((" FAT Begin LBA = 0x%x\r\n",fs->fat_begin_lba));
    FAT_PRINTF((" Cluster Begin LBA = 0x%x\r\n",fs->cluster_begin_lba));
    FAT_PRINTF((" Sectors Per Cluster = %d\r\n", fs->sectors_per_cluster));
}
//-----------------------------------------------------------------------------
// fatfs_get_root_cluster: Get the root dir cluster
//-----------------------------------------------------------------------------
uint32 fatfs_get_root_cluster(struct fatfs *fs)
{
    // NOTE: On FAT16 this will be 0 which has a special meaning...
    return fs->rootdir_first_cluster;
}
//-------------------------------------------------------------
// fatfs_get_file_entry: Find the file entry for a filename
//-------------------------------------------------------------
uint32 fatfs_get_file_entry(struct fatfs *fs, uint32 Cluster, char *name_to_find, struct fat_dir_entry *sfEntry)
{
    uint8 item=0;
    uint16 recordoffset = 0;
    uint8 i=0;
    int x=0;
    char *long_filename = NULL;
    char short_filename[13];
    struct lfn_cache lfn;
    int dotRequired = 0;
    struct fat_dir_entry *directoryEntry;

    fatfs_lfn_cache_init(&lfn, 1);

    // Main cluster following loop
    while (1)
    {
        // Read sector
        if (fatfs_sector_reader(fs, Cluster, x++, 0)) // If sector read was successfull
        {
            // Analyse Sector
            for (item = 0; item < FAT_DIR_ENTRIES_PER_SECTOR; item++)
            {
                // Create the multiplier for sector access
                recordoffset = FAT_DIR_ENTRY_SIZE * item;

                // Overlay directory entry over buffer
                directoryEntry = (struct fat_dir_entry*)(fs->currentsector.sector+recordoffset);

#if FATFS_INC_LFN_SUPPORT
                // Long File Name Text Found
                if (fatfs_entry_lfn_text(directoryEntry) )
                    fatfs_lfn_cache_entry(&lfn, fs->currentsector.sector+recordoffset);

                // If Invalid record found delete any long file name information collated
                else if (fatfs_entry_lfn_invalid(directoryEntry) )
                    fatfs_lfn_cache_init(&lfn, 0);

                // Normal SFN Entry and Long text exists
                else if (fatfs_entry_lfn_exists(&lfn, directoryEntry) )
                {
                    long_filename = fatfs_lfn_cache_get(&lfn);

                    // Compare names to see if they match
                    if (fatfs_compare_names(long_filename, name_to_find))
                    {
                        memcpy(sfEntry,directoryEntry,sizeof(struct fat_dir_entry));
                        return 1;
                    }

                    fatfs_lfn_cache_init(&lfn, 0);
                }
                else
#endif
                // Normal Entry, only 8.3 Text
                if (fatfs_entry_sfn_only(directoryEntry) )
                {
                    memset(short_filename, 0, sizeof(short_filename));

                    // Copy name to string
                    for (i=0; i<8; i++)
                        short_filename[i] = directoryEntry->Name[i];

                    // Extension
                    dotRequired = 0;
                    for (i=8; i<11; i++)
                    {
                        short_filename[i+1] = directoryEntry->Name[i];
                        if (directoryEntry->Name[i] != ' ')
                            dotRequired = 1;
                    }

                    // Dot only required if extension present
                    if (dotRequired)
                    {
                        // If not . or .. entry
                        if (short_filename[0]!='.')
                            short_filename[8] = '.';
                        else
                            short_filename[8] = ' ';
                    }
                    else
                        short_filename[8] = ' ';

                    // Compare names to see if they match
                    if (fatfs_compare_names(short_filename, name_to_find))
                    {
                        memcpy(sfEntry,directoryEntry,sizeof(struct fat_dir_entry));
                        return 1;
                    }

                    fatfs_lfn_cache_init(&lfn, 0);
                }
            } // End of if
        }
        else
            break;
    } // End of while loop

    return 0;
}
//-------------------------------------------------------------
// fatfs_sfn_exists: Check if a short filename exists.
// NOTE: shortname is XXXXXXXXYYY not XXXXXXXX.YYY
//-------------------------------------------------------------
#if FATFS_INC_WRITE_SUPPORT
int fatfs_sfn_exists(struct fatfs *fs, uint32 Cluster, char *shortname)
{
    uint8 item=0;
    uint16 recordoffset = 0;
    int x=0;
    struct fat_dir_entry *directoryEntry;

    // Main cluster following loop
    while (1)
    {
        // Read sector
        if (fatfs_sector_reader(fs, Cluster, x++, 0)) // If sector read was successfull
        {
            // Analyse Sector
            for (item = 0; item < FAT_DIR_ENTRIES_PER_SECTOR; item++)
            {
                // Create the multiplier for sector access
                recordoffset = FAT_DIR_ENTRY_SIZE * item;

                // Overlay directory entry over buffer
                directoryEntry = (struct fat_dir_entry*)(fs->currentsector.sector+recordoffset);

#if FATFS_INC_LFN_SUPPORT
                // Long File Name Text Found
                if (fatfs_entry_lfn_text(directoryEntry) )
                    ;

                // If Invalid record found delete any long file name information collated
                else if (fatfs_entry_lfn_invalid(directoryEntry) )
                    ;
                else
#endif
                // Normal Entry, only 8.3 Text
                if (fatfs_entry_sfn_only(directoryEntry) )
                {
                    if (strncmp((const char*)directoryEntry->Name, shortname, 11)==0)
                        return 1;
                }
            } // End of if
        }
        else
            break;
    } // End of while loop

    return 0;
}
#endif
//-------------------------------------------------------------
// fatfs_update_timestamps: Update date/time details
//-------------------------------------------------------------
#if FATFS_INC_TIME_DATE_SUPPORT
int fatfs_update_timestamps(struct fat_dir_entry *directoryEntry, int create, int modify, int access)
{
    time_t time_now;
    struct tm * time_info;
    uint16 fat_time;
    uint16 fat_date;

    // Get system time
    time(&time_now);

    // Convert to local time
    time_info = localtime(&time_now);

    // Convert time to FAT format
    fat_time = fatfs_convert_to_fat_time(time_info->tm_hour, time_info->tm_min, time_info->tm_sec);

    // Convert date to FAT format
    fat_date = fatfs_convert_to_fat_date(time_info->tm_mday, time_info->tm_mon + 1, time_info->tm_year + 1900);

    // Update requested fields
    if (create)
    {
        directoryEntry->CrtTime[1] = fat_time >> 8;
        directoryEntry->CrtTime[0] = fat_time >> 0;
        directoryEntry->CrtDate[1] = fat_date >> 8;
        directoryEntry->CrtDate[0] = fat_date >> 0;
    }

    if (modify)
    {
        directoryEntry->WrtTime[1] = fat_time >> 8;
        directoryEntry->WrtTime[0] = fat_time >> 0;
        directoryEntry->WrtDate[1] = fat_date >> 8;
        directoryEntry->WrtDate[0] = fat_date >> 0;
    }

    if (access)
    {
        directoryEntry->LstAccDate[1] = fat_time >> 8;
        directoryEntry->LstAccDate[0] = fat_time >> 0;
        directoryEntry->LstAccDate[1] = fat_date >> 8;
        directoryEntry->LstAccDate[0] = fat_date >> 0;
    }

    return 1;
}
#endif
//-------------------------------------------------------------
// fatfs_update_file_length: Find a SFN entry and update it
// NOTE: shortname is XXXXXXXXYYY not XXXXXXXX.YYY
//-------------------------------------------------------------
#if FATFS_INC_WRITE_SUPPORT
int fatfs_update_file_length(struct fatfs *fs, uint32 Cluster, char *shortname, uint32 fileLength)
{
    uint8 item=0;
    uint16 recordoffset = 0;
    int x=0;
    struct fat_dir_entry *directoryEntry;

    // No write access?
    if (!fs->disk_io.write_media)
        return 0;

    // Main cluster following loop
    while (1)
    {
        // Read sector
        if (fatfs_sector_reader(fs, Cluster, x++, 0)) // If sector read was successfull
        {
            // Analyse Sector
            for (item = 0; item < FAT_DIR_ENTRIES_PER_SECTOR; item++)
            {
                // Create the multiplier for sector access
                recordoffset = FAT_DIR_ENTRY_SIZE * item;

                // Overlay directory entry over buffer
                directoryEntry = (struct fat_dir_entry*)(fs->currentsector.sector+recordoffset);

#if FATFS_INC_LFN_SUPPORT
                // Long File Name Text Found
                if (fatfs_entry_lfn_text(directoryEntry) )
                    ;

                // If Invalid record found delete any long file name information collated
                else if (fatfs_entry_lfn_invalid(directoryEntry) )
                    ;

                // Normal Entry, only 8.3 Text
                else
#endif
                if (fatfs_entry_sfn_only(directoryEntry) )
                {
                    if (strncmp((const char*)directoryEntry->Name, shortname, 11)==0)
                    {
                        directoryEntry->FileSize = FAT_HTONL(fileLength);

#if FATFS_INC_TIME_DATE_SUPPORT
                        // Update access / modify time & date
                        fatfs_update_timestamps(directoryEntry, 0, 1, 1);
#endif

                        // Update sfn entry
                        memcpy((uint8*)(fs->currentsector.sector+recordoffset), (uint8*)directoryEntry, sizeof(struct fat_dir_entry));

                        // Write sector back
                        return fs->disk_io.write_media(fs->currentsector.address, fs->currentsector.sector, 1);
                    }
                }
            } // End of if
        }
        else
            break;
    } // End of while loop

    return 0;
}
#endif
//-------------------------------------------------------------
// fatfs_mark_file_deleted: Find a SFN entry and mark if as deleted
// NOTE: shortname is XXXXXXXXYYY not XXXXXXXX.YYY
//-------------------------------------------------------------
#if FATFS_INC_WRITE_SUPPORT
int fatfs_mark_file_deleted(struct fatfs *fs, uint32 Cluster, char *shortname)
{
    uint8 item=0;
    uint16 recordoffset = 0;
    int x=0;
    struct fat_dir_entry *directoryEntry;

    // No write access?
    if (!fs->disk_io.write_media)
        return 0;

    // Main cluster following loop
    while (1)
    {
        // Read sector
        if (fatfs_sector_reader(fs, Cluster, x++, 0)) // If sector read was successfull
        {
            // Analyse Sector
            for (item = 0; item < FAT_DIR_ENTRIES_PER_SECTOR; item++)
            {
                // Create the multiplier for sector access
                recordoffset = FAT_DIR_ENTRY_SIZE * item;

                // Overlay directory entry over buffer
                directoryEntry = (struct fat_dir_entry*)(fs->currentsector.sector+recordoffset);

#if FATFS_INC_LFN_SUPPORT
                // Long File Name Text Found
                if (fatfs_entry_lfn_text(directoryEntry) )
                    ;

                // If Invalid record found delete any long file name information collated
                else if (fatfs_entry_lfn_invalid(directoryEntry) )
                    ;

                // Normal Entry, only 8.3 Text
                else
#endif
                if (fatfs_entry_sfn_only(directoryEntry) )
                {
                    if (strncmp((const char *)directoryEntry->Name, shortname, 11)==0)
                    {
                        // Mark as deleted
                        directoryEntry->Name[0] = FILE_HEADER_DELETED;

#if FATFS_INC_TIME_DATE_SUPPORT
                        // Update access / modify time & date
                        fatfs_update_timestamps(directoryEntry, 0, 1, 1);
#endif

                        // Update sfn entry
                        memcpy((uint8*)(fs->currentsector.sector+recordoffset), (uint8*)directoryEntry, sizeof(struct fat_dir_entry));

                        // Write sector back
                        return fs->disk_io.write_media(fs->currentsector.address, fs->currentsector.sector, 1);
                    }
                }
            } // End of if
        }
        else
            break;
    } // End of while loop

    return 0;
}
#endif
//-----------------------------------------------------------------------------
// fatfs_list_directory_start: Initialise a directory listing procedure
//-----------------------------------------------------------------------------
#if FATFS_DIR_LIST_SUPPORT
void fatfs_list_directory_start(struct fatfs *fs, struct fs_dir_list_status *dirls, uint32 StartCluster)
{
    dirls->cluster = StartCluster;
    dirls->sector = 0;
    dirls->offset = 0;
}
#endif
//-----------------------------------------------------------------------------
// fatfs_list_directory_next: Get the next entry in the directory.
// Returns: 1 = found, 0 = end of listing
//-----------------------------------------------------------------------------
#if FATFS_DIR_LIST_SUPPORT
int fatfs_list_directory_next(struct fatfs *fs, struct fs_dir_list_status *dirls, struct fs_dir_ent *entry)
{
    uint8 i,item;
    uint16 recordoffset;
    struct fat_dir_entry *directoryEntry;
    char *long_filename = NULL;
    char short_filename[13];
    struct lfn_cache lfn;
    int dotRequired = 0;
    int result = 0;

    // Initialise LFN cache first
    fatfs_lfn_cache_init(&lfn, 0);

    while (1)
    {
        // If data read OK
        if (fatfs_sector_reader(fs, dirls->cluster, dirls->sector, 0))
        {
            // Maximum of 16 directory entries
            for (item = dirls->offset; item < FAT_DIR_ENTRIES_PER_SECTOR; item++)
            {
                // Increase directory offset
                recordoffset = FAT_DIR_ENTRY_SIZE * item;

                // Overlay directory entry over buffer
                directoryEntry = (struct fat_dir_entry*)(fs->currentsector.sector+recordoffset);

#if FATFS_INC_LFN_SUPPORT
                // Long File Name Text Found
                if ( fatfs_entry_lfn_text(directoryEntry) )
                    fatfs_lfn_cache_entry(&lfn, fs->currentsector.sector+recordoffset);

                // If Invalid record found delete any long file name information collated
                else if ( fatfs_entry_lfn_invalid(directoryEntry) )
                    fatfs_lfn_cache_init(&lfn, 0);

                // Normal SFN Entry and Long text exists
                else if (fatfs_entry_lfn_exists(&lfn, directoryEntry) )
                {
                    // Get text
                    long_filename = fatfs_lfn_cache_get(&lfn);
                    strcpy_s(entry->filename, FATFS_MAX_LONG_FILENAME - 1, long_filename);

                    if (fatfs_entry_is_dir(directoryEntry))
                        entry->is_dir = 1;
                    else
                        entry->is_dir = 0;

#if FATFS_INC_TIME_DATE_SUPPORT
                    // Get time / dates
                    entry->create_time = ((uint16)directoryEntry->CrtTime[1] << 8) | directoryEntry->CrtTime[0];
                    entry->create_date = ((uint16)directoryEntry->CrtDate[1] << 8) | directoryEntry->CrtDate[0];
                    entry->access_date = ((uint16)directoryEntry->LstAccDate[1] << 8) | directoryEntry->LstAccDate[0];
                    entry->write_time  = ((uint16)directoryEntry->WrtTime[1] << 8) | directoryEntry->WrtTime[0];
                    entry->write_date  = ((uint16)directoryEntry->WrtDate[1] << 8) | directoryEntry->WrtDate[0];
#endif

                    entry->size = FAT_HTONL(directoryEntry->FileSize);
                    entry->cluster = (FAT_HTONS(directoryEntry->FstClusHI)<<16) | FAT_HTONS(directoryEntry->FstClusLO);

                    // Next starting position
                    dirls->offset = item + 1;
                    result = 1;
                    return 1;
                }
                // Normal Entry, only 8.3 Text
                else
#endif
                if ( fatfs_entry_sfn_only(directoryEntry) )
                {
                    fatfs_lfn_cache_init(&lfn, 0);

                    memset(short_filename, 0, sizeof(short_filename));

                    // Copy name to string
                    for (i=0; i<8; i++)
                        short_filename[i] = directoryEntry->Name[i];

                    // Extension
                    dotRequired = 0;
                    for (i=8; i<11; i++)
                    {
                        short_filename[i+1] = directoryEntry->Name[i];
                        if (directoryEntry->Name[i] != ' ')
                            dotRequired = 1;
                    }

                    // Dot only required if extension present
                    if (dotRequired)
                    {
                        // If not . or .. entry
                        if (short_filename[0]!='.')
                            short_filename[8] = '.';
                        else
                            short_filename[8] = ' ';
                    }
                    else
                        short_filename[8] = ' ';

                    fatfs_get_sfn_display_name(entry->filename, short_filename);

                    if (fatfs_entry_is_dir(directoryEntry))
                        entry->is_dir = 1;
                    else
                        entry->is_dir = 0;

#if FATFS_INC_TIME_DATE_SUPPORT
                    // Get time / dates
                    entry->create_time = ((uint16)directoryEntry->CrtTime[1] << 8) | directoryEntry->CrtTime[0];
                    entry->create_date = ((uint16)directoryEntry->CrtDate[1] << 8) | directoryEntry->CrtDate[0];
                    entry->access_date = ((uint16)directoryEntry->LstAccDate[1] << 8) | directoryEntry->LstAccDate[0];
                    entry->write_time  = ((uint16)directoryEntry->WrtTime[1] << 8) | directoryEntry->WrtTime[0];
                    entry->write_date  = ((uint16)directoryEntry->WrtDate[1] << 8) | directoryEntry->WrtDate[0];
#endif

                    entry->size = FAT_HTONL(directoryEntry->FileSize);
                    entry->cluster = (FAT_HTONS(directoryEntry->FstClusHI)<<16) | FAT_HTONS(directoryEntry->FstClusLO);

                    // Next starting position
                    dirls->offset = item + 1;
                    result = 1;
                    return 1;
                }
            }// end of for

            // If reached end of the dir move onto next sector
            dirls->sector++;
            dirls->offset = 0;
        }
        else
            break;
    }

    return result;
}
#endif
