Copyright 1996-2003 John D. Polstra.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgment:
* This product includes software developed by John D. Polstra.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $Id: EscapedRd.m3.html,v 1.3 2010-04-29 17:20:02 wagner Exp $
MODULE EscapedRd;
IMPORT Atom, AtomList, Rd, RdClass, Thread;
REVEAL
T = Public BRANDED OBJECT
rd: Rd.T;
maxChildRead: CARDINAL;
closeChild: BOOLEAN;
eof := FALSE;
atBOL := TRUE;
newlinePending := FALSE;
OVERRIDES
init := Init;
seek := Seek;
length := Length;
close := Close;
END;
PROCEDURE Close(self: T)
RAISES {Rd.Failure, Thread.Alerted} =
BEGIN
IF self.closeChild THEN
Rd.Close(self.rd);
END;
END Close;
PROCEDURE Init(self: T;
rd: Rd.T;
maxChildRead: CARDINAL := LAST(CARDINAL);
closeChild: BOOLEAN := TRUE): T =
BEGIN
RdClass.Lock(self);
TRY
self.rd := rd;
self.maxChildRead := maxChildRead;
self.closeChild := closeChild;
self.buff := NEW(REF ARRAY OF CHAR, MIN(maxChildRead, 8192));
self.st := 0; (* Always. *)
self.seekable := FALSE;
self.intermittent := TRUE; (* Because we do not know the length. *)
self.closed := FALSE;
FINALLY
RdClass.Unlock(self);
END;
RETURN self;
END Init;
PROCEDURE Length(<*UNUSED*> self: T): INTEGER =
BEGIN
RETURN -1;
END Length;
PROCEDURE Raise(a: Atom.T)
RAISES {Rd.Failure} =
BEGIN
RAISE Rd.Failure(AtomList.List1(a));
END Raise;
PROCEDURE Seek(self: T; n: CARDINAL; dontBlock: BOOLEAN): RdClass.SeekResult
RAISES {Rd.Failure, Thread.Alerted} =
VAR
pos, lim, len: CARDINAL;
BEGIN
<* ASSERT n = self.cur *>
<* ASSERT self.cur = self.hi *>
self.lo := self.cur;
IF self.eof THEN (* End of stream already reached on previous call. *)
RETURN RdClass.SeekResult.Eof;
END;
IF dontBlock AND Rd.CharsReady(self.rd) = 0 THEN
RETURN RdClass.SeekResult.WouldBlock;
END;
pos := 0;
lim := NUMBER(self.buff^);
WHILE pos <= lim - 4 DO (* Note we leave room for at least "\n.+\n" *)
IF self.newlinePending THEN (* Insert pending newline from last time. *)
self.buff[pos] := '\n';
INC(pos);
END;
len := Rd.GetSubLine(self.rd, SUBARRAY(self.buff^, pos, lim-pos));
IF len = 0 THEN
Raise(PrematureEOF);
END;
IF self.atBOL AND self.buff[pos] = '.' THEN (* Escape sequence. *)
IF len < 2 THEN Raise(PrematureEOF) END;
CASE self.buff[pos+1] OF
| '.' =>
SUBARRAY(self.buff^, pos, len-1) :=
SUBARRAY(self.buff^, pos+1, len-1);
DEC(len);
| '\n' =>
self.eof := TRUE;
EXIT;
| '+' =>
IF len < 3 THEN Raise(PrematureEOF) END;
IF self.buff[pos+2] # '\n' THEN Raise(InvalidEscape) END;
IF pos > 0 THEN (* Erase the previous newline *)
<* ASSERT self.buff[pos-1] = '\n' *>
DEC(pos);
END;
self.eof := TRUE;
EXIT;
ELSE
Raise(InvalidEscape);
END;
END;
INC(pos, len);
IF self.buff[pos-1] = '\n' THEN
DEC(pos);
self.newlinePending := TRUE;
ELSE
self.newlinePending := FALSE;
END;
self.atBOL := self.newlinePending;
END;
self.hi := self.lo + pos;
IF pos = 0 THEN
<* ASSERT self.eof *>
RETURN RdClass.SeekResult.Eof;
END;
RETURN RdClass.SeekResult.Ready;
END Seek;
BEGIN
PrematureEOF := Atom.FromText("EscapedRd.PrematureEOF");
InvalidEscape := Atom.FromText("EscapedRd.InvalidEscape");
END EscapedRd.