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Ventoy/LinuxGUI/Ventoy2Disk/Lib/fat_io_lib/fat_table.c

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//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// 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"
#ifndef FAT_BUFFERS
#define FAT_BUFFERS 1
#endif
#ifndef FAT_BUFFER_SECTORS
#define FAT_BUFFER_SECTORS 1
#endif
#if FAT_BUFFERS < 1 || FAT_BUFFER_SECTORS < 1
#error "FAT_BUFFERS & FAT_BUFFER_SECTORS must be at least 1"
#endif
//-----------------------------------------------------------------------------
// FAT Sector Buffer
//-----------------------------------------------------------------------------
#define FAT32_GET_32BIT_WORD(pbuf, location) ( GET_32BIT_WORD(pbuf->ptr, location) )
#define FAT32_SET_32BIT_WORD(pbuf, location, value) { SET_32BIT_WORD(pbuf->ptr, location, value); pbuf->dirty = 1; }
#define FAT16_GET_16BIT_WORD(pbuf, location) ( GET_16BIT_WORD(pbuf->ptr, location) )
#define FAT16_SET_16BIT_WORD(pbuf, location, value) { SET_16BIT_WORD(pbuf->ptr, location, value); pbuf->dirty = 1; }
//-----------------------------------------------------------------------------
// fatfs_fat_init:
//-----------------------------------------------------------------------------
void fatfs_fat_init(struct fatfs *fs)
{
int i;
// FAT buffer chain head
fs->fat_buffer_head = NULL;
for (i=0;i<FAT_BUFFERS;i++)
{
// Initialise buffers to invalid
fs->fat_buffers[i].address = FAT32_INVALID_CLUSTER;
fs->fat_buffers[i].dirty = 0;
memset(fs->fat_buffers[i].sector, 0x00, sizeof(fs->fat_buffers[i].sector));
fs->fat_buffers[i].ptr = NULL;
// Add to head of queue
fs->fat_buffers[i].next = fs->fat_buffer_head;
fs->fat_buffer_head = &fs->fat_buffers[i];
}
}
//-----------------------------------------------------------------------------
// fatfs_fat_writeback: Writeback 'dirty' FAT sectors to disk
//-----------------------------------------------------------------------------
static int fatfs_fat_writeback(struct fatfs *fs, struct fat_buffer *pcur)
{
if (pcur)
{
// Writeback sector if changed
if (pcur->dirty)
{
if (fs->disk_io.write_media)
{
uint32 sectors = FAT_BUFFER_SECTORS;
uint32 offset = pcur->address - fs->fat_begin_lba;
// Limit to sectors used for the FAT
if ((offset + FAT_BUFFER_SECTORS) <= fs->fat_sectors)
sectors = FAT_BUFFER_SECTORS;
else
sectors = fs->fat_sectors - offset;
if (!fs->disk_io.write_media(pcur->address, pcur->sector, sectors))
return 0;
}
pcur->dirty = 0;
}
return 1;
}
else
return 0;
}
//-----------------------------------------------------------------------------
// fatfs_fat_read_sector: Read a FAT sector
//-----------------------------------------------------------------------------
static struct fat_buffer *fatfs_fat_read_sector(struct fatfs *fs, uint32 sector)
{
struct fat_buffer *last = NULL;
struct fat_buffer *pcur = fs->fat_buffer_head;
// Itterate through sector buffer list
while (pcur)
{
// Sector within this buffer?
if ((sector >= pcur->address) && (sector < (pcur->address + FAT_BUFFER_SECTORS)))
break;
// End of list?
if (pcur->next == NULL)
{
// Remove buffer from list
if (last)
last->next = NULL;
// We the first and last buffer in the chain?
else
fs->fat_buffer_head = NULL;
}
last = pcur;
pcur = pcur->next;
}
// We found the sector already in FAT buffer chain
if (pcur)
{
pcur->ptr = (uint8 *)(pcur->sector + ((sector - pcur->address) * FAT_SECTOR_SIZE));
return pcur;
}
// Else, we removed the last item from the list
pcur = last;
// Add to start of sector buffer list (now newest sector)
pcur->next = fs->fat_buffer_head;
fs->fat_buffer_head = pcur;
// Writeback sector if changed
if (pcur->dirty)
if (!fatfs_fat_writeback(fs, pcur))
return 0;
// Address is now new sector
pcur->address = sector;
// Read next sector
if (!fs->disk_io.read_media(pcur->address, pcur->sector, FAT_BUFFER_SECTORS))
{
// Read failed, invalidate buffer address
pcur->address = FAT32_INVALID_CLUSTER;
return NULL;
}
pcur->ptr = pcur->sector;
return pcur;
}
//-----------------------------------------------------------------------------
// fatfs_fat_purge: Purge 'dirty' FAT sectors to disk
//-----------------------------------------------------------------------------
int fatfs_fat_purge(struct fatfs *fs)
{
struct fat_buffer *pcur = fs->fat_buffer_head;
// Itterate through sector buffer list
while (pcur)
{
// Writeback sector if changed
if (pcur->dirty)
if (!fatfs_fat_writeback(fs, pcur))
return 0;
pcur = pcur->next;
}
return 1;
}
//-----------------------------------------------------------------------------
// General FAT Table Operations
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// fatfs_find_next_cluster: Return cluster number of next cluster in chain by
// reading FAT table and traversing it. Return 0xffffffff for end of chain.
//-----------------------------------------------------------------------------
uint32 fatfs_find_next_cluster(struct fatfs *fs, uint32 current_cluster)
{
uint32 fat_sector_offset, position;
uint32 nextcluster;
struct fat_buffer *pbuf;
// Why is '..' labelled with cluster 0 when it should be 2 ??
if (current_cluster == 0)
current_cluster = 2;
// Find which sector of FAT table to read
if (fs->fat_type == FAT_TYPE_16)
fat_sector_offset = current_cluster / 256;
else
fat_sector_offset = current_cluster / 128;
// Read FAT sector into buffer
pbuf = fatfs_fat_read_sector(fs, fs->fat_begin_lba+fat_sector_offset);
if (!pbuf)
return (FAT32_LAST_CLUSTER);
if (fs->fat_type == FAT_TYPE_16)
{
// Find 32 bit entry of current sector relating to cluster number
position = (current_cluster - (fat_sector_offset * 256)) * 2;
// Read Next Clusters value from Sector Buffer
nextcluster = FAT16_GET_16BIT_WORD(pbuf, (uint16)position);
// If end of chain found
if (nextcluster >= 0xFFF8 && nextcluster <= 0xFFFF)
return (FAT32_LAST_CLUSTER);
}
else
{
// Find 32 bit entry of current sector relating to cluster number
position = (current_cluster - (fat_sector_offset * 128)) * 4;
// Read Next Clusters value from Sector Buffer
nextcluster = FAT32_GET_32BIT_WORD(pbuf, (uint16)position);
// Mask out MS 4 bits (its 28bit addressing)
nextcluster = nextcluster & 0x0FFFFFFF;
// If end of chain found
if (nextcluster >= 0x0FFFFFF8 && nextcluster <= 0x0FFFFFFF)
return (FAT32_LAST_CLUSTER);
}
// Else return next cluster
return (nextcluster);
}
//-----------------------------------------------------------------------------
// fatfs_set_fs_info_next_free_cluster: Write the next free cluster to the FSINFO table
//-----------------------------------------------------------------------------
void fatfs_set_fs_info_next_free_cluster(struct fatfs *fs, uint32 newValue)
{
if (fs->fat_type == FAT_TYPE_16)
;
else
{
// Load sector to change it
struct fat_buffer *pbuf = fatfs_fat_read_sector(fs, fs->lba_begin+fs->fs_info_sector);
if (!pbuf)
return ;
// Change
FAT32_SET_32BIT_WORD(pbuf, 492, newValue);
fs->next_free_cluster = newValue;
// Write back FSINFO sector to disk
if (fs->disk_io.write_media)
fs->disk_io.write_media(pbuf->address, pbuf->sector, 1);
// Invalidate cache entry
pbuf->address = FAT32_INVALID_CLUSTER;
pbuf->dirty = 0;
}
}
//-----------------------------------------------------------------------------
// fatfs_find_blank_cluster: Find a free cluster entry by reading the FAT
//-----------------------------------------------------------------------------
#if FATFS_INC_WRITE_SUPPORT
int fatfs_find_blank_cluster(struct fatfs *fs, uint32 start_cluster, uint32 *free_cluster)
{
uint32 fat_sector_offset, position;
uint32 nextcluster;
uint32 current_cluster = start_cluster;
struct fat_buffer *pbuf;
do
{
// Find which sector of FAT table to read
if (fs->fat_type == FAT_TYPE_16)
fat_sector_offset = current_cluster / 256;
else
fat_sector_offset = current_cluster / 128;
if ( fat_sector_offset < fs->fat_sectors)
{
// Read FAT sector into buffer
pbuf = fatfs_fat_read_sector(fs, fs->fat_begin_lba+fat_sector_offset);
if (!pbuf)
return 0;
if (fs->fat_type == FAT_TYPE_16)
{
// Find 32 bit entry of current sector relating to cluster number
position = (current_cluster - (fat_sector_offset * 256)) * 2;
// Read Next Clusters value from Sector Buffer
nextcluster = FAT16_GET_16BIT_WORD(pbuf, (uint16)position);
}
else
{
// Find 32 bit entry of current sector relating to cluster number
position = (current_cluster - (fat_sector_offset * 128)) * 4;
// Read Next Clusters value from Sector Buffer
nextcluster = FAT32_GET_32BIT_WORD(pbuf, (uint16)position);
// Mask out MS 4 bits (its 28bit addressing)
nextcluster = nextcluster & 0x0FFFFFFF;
}
if (nextcluster !=0 )
current_cluster++;
}
else
// Otherwise, run out of FAT sectors to check...
return 0;
}
while (nextcluster != 0x0);
// Found blank entry
*free_cluster = current_cluster;
return 1;
}
#endif
//-----------------------------------------------------------------------------
// fatfs_fat_set_cluster: Set a cluster link in the chain. NOTE: Immediate
// write (slow).
//-----------------------------------------------------------------------------
#if FATFS_INC_WRITE_SUPPORT
int fatfs_fat_set_cluster(struct fatfs *fs, uint32 cluster, uint32 next_cluster)
{
struct fat_buffer *pbuf;
uint32 fat_sector_offset, position;
// Find which sector of FAT table to read
if (fs->fat_type == FAT_TYPE_16)
fat_sector_offset = cluster / 256;
else
fat_sector_offset = cluster / 128;
// Read FAT sector into buffer
pbuf = fatfs_fat_read_sector(fs, fs->fat_begin_lba+fat_sector_offset);
if (!pbuf)
return 0;
if (fs->fat_type == FAT_TYPE_16)
{
// Find 16 bit entry of current sector relating to cluster number
position = (cluster - (fat_sector_offset * 256)) * 2;
// Write Next Clusters value to Sector Buffer
FAT16_SET_16BIT_WORD(pbuf, (uint16)position, ((uint16)next_cluster));
}
else
{
// Find 32 bit entry of current sector relating to cluster number
position = (cluster - (fat_sector_offset * 128)) * 4;
// Write Next Clusters value to Sector Buffer
FAT32_SET_32BIT_WORD(pbuf, (uint16)position, next_cluster);
}
return 1;
}
#endif
//-----------------------------------------------------------------------------
// fatfs_free_cluster_chain: Follow a chain marking each element as free
//-----------------------------------------------------------------------------
#if FATFS_INC_WRITE_SUPPORT
int fatfs_free_cluster_chain(struct fatfs *fs, uint32 start_cluster)
{
uint32 last_cluster;
uint32 next_cluster = start_cluster;
// Loop until end of chain
while ( (next_cluster != FAT32_LAST_CLUSTER) && (next_cluster != 0x00000000) )
{
last_cluster = next_cluster;
// Find next link
next_cluster = fatfs_find_next_cluster(fs, next_cluster);
// Clear last link
fatfs_fat_set_cluster(fs, last_cluster, 0x00000000);
}
return 1;
}
#endif
//-----------------------------------------------------------------------------
// fatfs_fat_add_cluster_to_chain: Follow a chain marking and then add a new entry
// to the current tail.
//-----------------------------------------------------------------------------
#if FATFS_INC_WRITE_SUPPORT
int fatfs_fat_add_cluster_to_chain(struct fatfs *fs, uint32 start_cluster, uint32 newEntry)
{
uint32 last_cluster = FAT32_LAST_CLUSTER;
uint32 next_cluster = start_cluster;
if (start_cluster == FAT32_LAST_CLUSTER)
return 0;
// Loop until end of chain
while ( next_cluster != FAT32_LAST_CLUSTER )
{
last_cluster = next_cluster;
// Find next link
next_cluster = fatfs_find_next_cluster(fs, next_cluster);
if (!next_cluster)
return 0;
}
// Add link in for new cluster
fatfs_fat_set_cluster(fs, last_cluster, newEntry);
// Mark new cluster as end of chain
fatfs_fat_set_cluster(fs, newEntry, FAT32_LAST_CLUSTER);
return 1;
}
#endif
//-----------------------------------------------------------------------------
// fatfs_count_free_clusters:
//-----------------------------------------------------------------------------
uint32 fatfs_count_free_clusters(struct fatfs *fs)
{
uint32 i,j;
uint32 count = 0;
struct fat_buffer *pbuf;
for (i = 0; i < fs->fat_sectors; i++)
{
// Read FAT sector into buffer
pbuf = fatfs_fat_read_sector(fs, fs->fat_begin_lba + i);
if (!pbuf)
break;
for (j = 0; j < FAT_SECTOR_SIZE; )
{
if (fs->fat_type == FAT_TYPE_16)
{
if (FAT16_GET_16BIT_WORD(pbuf, (uint16)j) == 0)
count++;
j += 2;
}
else
{
if (FAT32_GET_32BIT_WORD(pbuf, (uint16)j) == 0)
count++;
j += 4;
}
}
}
return count;
}
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