| bigbiff bigbiff | 9c75405 | 2013-01-09 09:09:08 -0500 | [diff] [blame] | 1 | /* fat.h - Read/write access to the FAT |
| 2 | |
| 3 | Copyright (C) 1993 Werner Almesberger <werner.almesberger@lrc.di.epfl.ch> |
| 4 | |
| 5 | This program is free software: you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation, either version 3 of the License, or |
| 8 | (at your option) any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 17 | |
| 18 | On Debian systems, the complete text of the GNU General Public License |
| 19 | can be found in /usr/share/common-licenses/GPL-3 file. |
| 20 | */ |
| 21 | |
| 22 | #ifndef _FAT_H |
| 23 | #define _FAT_H |
| 24 | |
| 25 | void read_fat(DOS_FS * fs); |
| 26 | |
| 27 | /* Loads the FAT of the file system described by FS. Initializes the FAT, |
| 28 | replaces broken FATs and rejects invalid cluster entries. */ |
| 29 | |
| 30 | void get_fat(FAT_ENTRY * entry, void *fat, unsigned long cluster, DOS_FS * fs); |
| 31 | |
| 32 | /* Retrieve the FAT entry (next chained cluster) for CLUSTER. */ |
| 33 | |
| 34 | void set_fat(DOS_FS * fs, unsigned long cluster, unsigned long new); |
| 35 | |
| 36 | /* Changes the value of the CLUSTERth cluster of the FAT of FS to NEW. Special |
| 37 | values of NEW are -1 (EOF, 0xff8 or 0xfff8) and -2 (bad sector, 0xff7 or |
| 38 | 0xfff7) */ |
| 39 | |
| 40 | int bad_cluster(DOS_FS * fs, unsigned long cluster); |
| 41 | |
| 42 | /* Returns a non-zero integer if the CLUSTERth cluster is marked as bad or zero |
| 43 | otherwise. */ |
| 44 | |
| 45 | unsigned long next_cluster(DOS_FS * fs, unsigned long cluster); |
| 46 | |
| 47 | /* Returns the number of the cluster following CLUSTER, or -1 if this is the |
| 48 | last cluster of the respective cluster chain. CLUSTER must not be a bad |
| 49 | cluster. */ |
| 50 | |
| 51 | loff_t cluster_start(DOS_FS * fs, unsigned long cluster); |
| 52 | |
| 53 | /* Returns the byte offset of CLUSTER, relative to the respective device. */ |
| 54 | |
| 55 | void set_owner(DOS_FS * fs, unsigned long cluster, DOS_FILE * owner); |
| 56 | |
| 57 | /* Sets the owner pointer of the respective cluster to OWNER. If OWNER was NULL |
| 58 | before, it can be set to NULL or any non-NULL value. Otherwise, only NULL is |
| 59 | accepted as the new value. */ |
| 60 | |
| 61 | DOS_FILE *get_owner(DOS_FS * fs, unsigned long cluster); |
| 62 | |
| 63 | /* Returns the owner of the repective cluster or NULL if the cluster has no |
| 64 | owner. */ |
| 65 | |
| 66 | void fix_bad(DOS_FS * fs); |
| 67 | |
| 68 | /* Scans the disk for currently unused bad clusters and marks them as bad. */ |
| 69 | |
| 70 | void reclaim_free(DOS_FS * fs); |
| 71 | |
| 72 | /* Marks all allocated, but unused clusters as free. */ |
| 73 | |
| 74 | void reclaim_file(DOS_FS * fs); |
| 75 | |
| 76 | /* Scans the FAT for chains of allocated, but unused clusters and creates files |
| 77 | for them in the root directory. Also tries to fix all inconsistencies (e.g. |
| 78 | loops, shared clusters, etc.) in the process. */ |
| 79 | |
| 80 | unsigned long update_free(DOS_FS * fs); |
| 81 | |
| 82 | /* Updates free cluster count in FSINFO sector. */ |
| 83 | |
| 84 | #endif |