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64 lines
1.9 KiB
C
64 lines
1.9 KiB
C
/* fat.h - Read/write access to the FAT */
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/* Written 1993 by Werner Almesberger */
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#ifndef _FAT_H
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#define _FAT_H
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void read_fat(DOS_FS *fs);
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/* Loads the FAT of the file system described by FS. Initializes the FAT,
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replaces broken FATs and rejects invalid cluster entries. */
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void set_fat(DOS_FS *fs,unsigned long cluster,unsigned long new);
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/* Changes the value of the CLUSTERth cluster of the FAT of FS to NEW. Special
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values of NEW are -1 (EOF, 0xff8 or 0xfff8) and -2 (bad sector, 0xff7 or
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0xfff7) */
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int bad_cluster(DOS_FS *fs,unsigned long cluster);
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/* Returns a non-zero integer if the CLUSTERth cluster is marked as bad or zero
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otherwise. */
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unsigned long next_cluster(DOS_FS *fs,unsigned long cluster);
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/* Returns the number of the cluster following CLUSTER, or -1 if this is the
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last cluster of the respective cluster chain. CLUSTER must not be a bad
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cluster. */
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loff_t cluster_start(DOS_FS *fs,unsigned long cluster);
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/* Returns the byte offset of CLUSTER, relative to the respective device. */
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void set_owner(DOS_FS *fs,unsigned long cluster,DOS_FILE *owner);
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/* Sets the owner pointer of the respective cluster to OWNER. If OWNER was NULL
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before, it can be set to NULL or any non-NULL value. Otherwise, only NULL is
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accepted as the new value. */
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DOS_FILE *get_owner(DOS_FS *fs,unsigned long cluster);
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/* Returns the owner of the repective cluster or NULL if the cluster has no
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owner. */
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void fix_bad(DOS_FS *fs);
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/* Scans the disk for currently unused bad clusters and marks them as bad. */
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void reclaim_free(DOS_FS *fs);
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/* Marks all allocated, but unused clusters as free. */
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void reclaim_file(DOS_FS *fs);
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/* Scans the FAT for chains of allocated, but unused clusters and creates files
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for them in the root directory. Also tries to fix all inconsistencies (e.g.
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loops, shared clusters, etc.) in the process. */
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unsigned long update_free(DOS_FS *fs);
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/* Updates free cluster count in FSINFO sector. */
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#endif
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