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80 lines
3.0 KiB
80 lines
3.0 KiB
/* rm.h - include file for rm and undel facility
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*
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* Revision History:
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* ??-???-???? ?? Created
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* 27-Dec-1989 SB Added new index file header stuff
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*
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* Index file format:
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* The indexed file is composed of records of length RM_RECLEN.
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* The old index file was composed of entries each the size of a record
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* and composed of filename padded by NULs. The hash function mapped the
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* Nth record (i.e. Nth INDEXED entry) to 'deleted.xxx', where, 'xxx' is (N+1)
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* padded by leading zeroes.
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* The new index file has an header record, rm_header, followed by entries
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* of one or more records padded by NULs. Longfilenames occupy multiple
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* records. The hash function maps the entry starting at Nth record to
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* 'deleted.xxx' where xxx is (N+1) padded by leading zeroes. This works out
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* to be basically the same as that for the old format. The differences are :-
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* -No entry is mapped to 'deleted.000'
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* -Entries for filenames longer than (RM_RECLEN-1) bytes cause gaps in
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* mapping.
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*
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* Notes:
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* RM/EXP/UNDEL work as follows:-
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* 'RM foo' saves a copy of 'foo' and places it in an hidden
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* sub-directory of RM_DIR (of foo) as file 'deleted.xxx', where, xxx is
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* determined from the index file RM_IDX in RM_DIR. An entry is made in
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* the index file for this.
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* 'UNDEL foo' reads the index file in RM_DIR and determines xxx for
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* foo and renames 'deleted.xxx' as foo. The entry for foo in the index
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* file is filled with NULLs.
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* 'EXP' picks up the index file from RM_DIR and deletes 'deleted.xxx'
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* for each entry in the index file. It then deletes the index file and
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* RM_DIR.
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*
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* The new index file format can coexist with the old one because :-
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* The header has a starting NULL which causes it to be ignored by
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* the old utilities,
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* When the old utilities attempt to read in a long filename entry they
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* fail without harm as the hashed 'deleted.xx' does not exist.
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*/
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#define RM_DIR "deleted."
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#define RM_IDX "index."
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#define RM_RECLEN 16
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/* The header record in the index file has
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* '\0IXn.nn\0' padded to RM_RECLEN bytes
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*/
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#define RM_SIG (char)0x00
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#define RM_MAGIC "IX" /* IX - IndeXed file */
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#define RM_VER "1.01"
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#define RM_NULL "\0"
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/* Forms header for Index file using RM_MAGIC, RM_VER and RM_NULL */
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extern char rm_header[RM_RECLEN];
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/* Function prototypes */
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// Converts Index file to the new format
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int convertIdxFile (int fhidx, char *dir);
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// Determines if the record is a new index file header
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flagType fIdxHdr (char *rec);
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// Reads an Index file record
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int readIdxRec (int fhIdx, char *rec);
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// Reads index file records and returns INDEXED entry
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int readNewIdxRec (int fhIdx, char *szRec, unsigned int cbMax);
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// Writes an new index file header
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int writeIdxHdr (int fhIdx);
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// Writes an index file record
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int writeIdxRec (int fhIdx, char *rec);
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// Indexes an entry into the Index file
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int writeNewIdxRec (int fhIdx, char *szRec);
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