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