libfat/source/file_allocation_table.h

75 lines
2.8 KiB
C

/*
file_allocation_table.h
Reading, writing and manipulation of the FAT structure on
a FAT partition
Copyright (c) 2006 Michael "Chishm" Chisholm
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
2006-07-11 - Chishm
* Original release
2006-10-01 - Chishm
* Added _FAT_fat_linkFreeClusterCleared to clear a cluster when it is allocated
2007-10-25 - Chishm
* Use CLUSTER_ERROR when an error occurs with the FAT, not CLUSTER_FREE
*/
#ifndef _FAT_H
#define _FAT_H
#include "common.h"
#include "partition.h"
#define CLUSTER_EOF_16 0xFFFF
#define CLUSTER_EOF 0x0FFFFFFF
#define CLUSTER_FREE 0x00000000
#define CLUSTER_FIRST 0x00000002
#define CLUSTER_ERROR 0xFFFFFFFF
#define CLUSTERS_PER_FAT12 4085
#define CLUSTERS_PER_FAT16 65525
u32 _FAT_fat_nextCluster(PARTITION* partition, u32 cluster);
u32 _FAT_fat_linkFreeCluster(PARTITION* partition, u32 cluster);
u32 _FAT_fat_linkFreeClusterCleared (PARTITION* partition, u32 cluster);
bool _FAT_fat_clearLinks (PARTITION* partition, u32 cluster);
u32 _FAT_fat_lastCluster (PARTITION* partition, u32 cluster);
u32 _FAT_fat_freeClusterCount (PARTITION* partition);
static inline u32 _FAT_fat_clusterToSector (PARTITION* partition, u32 cluster) {
return (cluster >= CLUSTER_FIRST) ? ((cluster - CLUSTER_FIRST) * partition->sectorsPerCluster) + partition->dataStart : partition->rootDirStart;
}
static inline bool _FAT_fat_isValidCluster (PARTITION* partition, u32 cluster) {
return (cluster >= CLUSTER_FIRST) && (cluster <= partition->fat.lastCluster /* This will catch CLUSTER_ERROR */);
}
#endif // _FAT_H