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MODULE MyFiles;
IMPORT Files;
TYPE File* =
POINTER TO RECORD
native: Files.File;
current: INTEGER;
END;
TYPE Rider* =
RECORD
base: File;
id: INTEGER;
eof-: BOOLEAN;
END;
VAR stamp: INTEGER;
PROCEDURE Open(name, mode: ARRAY OF CHAR): File;
VAR f: File; g: Files.File;
BEGIN
g := Files.Open(name, mode);
IF g = NIL THEN
RETURN NIL
ELSE
NEW(f);
f.native := g; f.current := 0;
RETURN f
END
END Open;
PROCEDURE New*(name: ARRAY OF CHAR): File;
BEGIN
RETURN Open(name, "w+")
END New;
PROCEDURE Old*(name: ARRAY OF CHAR): File;
BEGIN
RETURN Open(name, "r")
END Old;
(* End of file behaviour: EOF is initially false; trying to read beyond the
end of the file returns a CHR(0) and sets the EOF flag. *)
PROCEDURE Set*(VAR r: Rider; f: File; off: INTEGER);
BEGIN
Files.Seek(f.native, off, Files.SeekSet);
r.base := f;
r.eof := FALSE;
stamp := stamp+1;
r.id := stamp;
f.current := stamp;
END Set;
PROCEDURE Read*(VAR r: Rider; VAR ch: CHAR);
VAR f: File;
BEGIN
f := r.base;
ASSERT(f.current = r.id);
IF Files.Eof(f.native) THEN
ch := CHR(0); r.eof := TRUE
ELSE
Files.ReadChar(f.native, ch)
END
END Read;
PROCEDURE Write*(VAR r: Rider; ch: CHAR);
BEGIN
ASSERT(r.base.current = r.id);
Files.WriteChar(r.base.native, ch)
END Write;
PROCEDURE WriteBytes*(VAR r: Rider; buf: ARRAY OF CHAR; len: INTEGER);
VAR i: INTEGER;
BEGIN
ASSERT(r.base.current = r.id);
FOR i := 0 TO len-1 DO
Files.WriteChar(r.base.native, buf[i])
END
END WriteBytes;
PROCEDURE WriteLongReal*(VAR r: Rider; x: LONGREAL);
BEGIN
ASSERT(r.base.current = r.id);
IF x = 0.0 THEN
Files.WriteString(r.base.native, "0")
ELSE
Files.WriteLongReal(r.base.native, x)
END
END WriteLongReal;
PROCEDURE Close*(f: File);
BEGIN
Files.Close(f.native)
END Close;
PROCEDURE Register*(f: File);
BEGIN
END Register;
(* Unix system call *)
PROCEDURE unlink(name: ARRAY OF CHAR): INTEGER IS "=unlink";
PROCEDURE Delete*(name: ARRAY OF CHAR; VAR res: INTEGER);
BEGIN
res := unlink(name)
END Delete;
END MyFiles.
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