home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
OS/2 Shareware BBS: 10 Tools
/
10-Tools.zip
/
xco212p.zip
/
ISODEF
/
rndfile.def
< prev
next >
Wrap
Text File
|
1996-01-09
|
4KB
|
105 lines
DEFINITION MODULE RndFile;
(* Random access files *)
IMPORT IOChan, ChanConsts, SYSTEM;
TYPE
ChanId = IOChan.ChanId;
FlagSet = ChanConsts.FlagSet;
OpenResults = ChanConsts.OpenResults;
(* Accepted singleton values of FlagSet *)
CONST
read = FlagSet{ChanConsts.readFlag}; (* input operations are requested/available *)
write = FlagSet{ChanConsts.writeFlag}; (* output operations are requested/available *)
old = FlagSet{ChanConsts.oldFlag}; (* a file may/must/did exist before the channel is
opened *)
text = FlagSet{ChanConsts.textFlag}; (* text operations are requested/available *)
raw = FlagSet{ChanConsts.rawFlag}; (* raw operations are requested/available *)
PROCEDURE OpenOld (VAR cid: ChanId; name: ARRAY OF CHAR; flags: FlagSet;
VAR res: OpenResults);
(* Attempts to obtain and open a channel connected to a stored random access file of the
given name.
The old flag is implied; without the write flag, read is implied; without the text
flag, raw is implied.
If successful, assigns to cid the identity of the opened channel, assigns the value
opened to res, and sets the read/write position to the start of the file.
If a channel cannot be opened as required, the value of res indicates the reason, and
cid identifies the invalid channel.
*)
PROCEDURE OpenClean (VAR cid: ChanId; name: ARRAY OF CHAR; flags: FlagSet;
VAR res: OpenResults);
(* Attempts to obtain and open a channel connected to a stored random access file of the
given name.
The write flag is implied; without the text flag, raw is implied.
If successful, assigns to cid the identity of the opened channel, assigns the value
opened to res, and truncates the file to zero length.
If a channel cannot be opened as required, the value of res indicates the reason, and
cid identifies the invalid channel.
*)
PROCEDURE IsRndFile (cid: ChanId): BOOLEAN;
(* Tests if the channel identified by cid is open to a random access file. *)
PROCEDURE IsRndFileException (): BOOLEAN;
(* Returns TRUE if the current coroutine is in the exceptional execution state because
of the raising of a RndFile exception; otherwise returns FALSE.
*)
CONST
FilePosSize = 4;
(*<implementation-defined whole number greater than zero>;*)
TYPE
<*# IF __GEN_386__ THEN *>
(* old front-end does not support array of LOCs *)
FilePos = CARDINAL;
<*# ELSIF __GEN_X86__ & (env_target = "x86os2") THEN *>
FilePos = CARDINAL;
<*# ELSE *>
FilePos = ARRAY [1 .. FilePosSize] OF SYSTEM.LOC;
<*# END *>
PROCEDURE StartPos (cid: ChanId): FilePos;
(* If the channel identified by cid is not open to a random access file, the exception
wrongDevice is raised; otherwise returns the position of the start of the file.
*)
PROCEDURE CurrentPos (cid: ChanId): FilePos;
(* If the channel identified by cid is not open to a random access file, the exception
wrongDevice is raised; otherwise returns the position of the current read/write
position.
*)
PROCEDURE EndPos (cid: ChanId): FilePos;
(* If the channel identified by cid is not open to a random access file, the exception
wrongDevice is raised; otherwise returns the first position after which there have been
no writes.
*)
PROCEDURE NewPos (cid: ChanId; chunks: INTEGER; chunkSize: CARDINAL; from: FilePos): FilePos;
(* If the channel identified by cid is not open to a random access file, the exception
wrongDevice is raised; otherwise returns the position (chunks * chunkSize) relative to
the position given by from, or raises the exception posRange if the required position
cannot be represented as a value of type FilePos.
*)
PROCEDURE SetPos (cid: ChanId; pos: FilePos);
(* If the channel identified by cid is not open to a random access file, the exception
wrongDevice is raised; otherwise sets the read/write position to the value given by
pos.
*)
PROCEDURE Close (VAR cid: ChanId);
(* If the channel identified by cid is not open to a random access file, the exception
wrongDevice is raised; otherwise closes the channel, and assigns the value identifying
the invalid channel to cid.
*)
END RndFile.