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Modules/nile/draft/Nile3Part.java

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+/*   
+Nile3Part.java
+ *    
+ *    Copyright (c) 2000, Ted Nelson and Tuomas Lukka
+ *
+ *    You may use and distribute under the terms of either the GNU Lesser
+ *    General Public License, either version 2 of the license or,
+ *    at your choice, any later version. Alternatively, you may use and
+ *    distribute under the terms of the XPL.
+ *
+ *    See the LICENSE.lgpl and LICENSE.xpl files for the specific terms of 
+ *    the licenses.
+ *
+ *    This software is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the README
+ *    file for more details.
+ *
+ */
+/*
+ * Written by Benjamin Fallenstein
+ */
+
+package org.gzigzag.module;
+import org.gzigzag.*;
+
+/** A Nile span, with a start and an end.
+ * This object explicitly assumes no modifications to the 
+ * stream while it is working.
+ */
+
+public final class Nile3Part implements Cloneable {
+public static final String rcsid = "$Id: Nile3Part.java,v 1.1 2001/01/07 18:59:06 bfallenstein Exp $";
+    public static boolean dbg = true;
+    static final void p(String s) { if(dbg) System.out.println(s); }
+    static final void pa(String s) { System.out.println(s); }
+
+    public final Nile3Pos start = new Nile3Pos();
+    public final Nile3Pos end = new Nile3Pos();
+
+    public Nile3Part(Nile3Pos start, Nile3Pos end) {
+	this.start.set(start); this.end.set(end);
+	check();
+    }
+    public Nile3Part(ZZCursor start, ZZCursor end) {
+	p(start + " " + end);
+	this.start.set(start); this.end.set(end);
+	check();
+    }
+
+    public Nile3Pos side(int dir) {
+	if(dir < 0) return start;
+	else return end;
+    }
+
+    public Nile3Pos cut() {
+	if(isStream())
+	    return null; // XXX should this throw an error?
+	check();
+	start.split(false, 1);
+	end.split(false, -1);
+	Nile3Pos before = (Nile3Pos)start.clone();
+	Nile3Pos after = (Nile3Pos)end.clone();
+	if(!before.bias(-1) || !after.bias(1))
+	    throw new ZZError("HELP! End of stream after split! XXX");
+	start.c.disconnect("d.nile", -1);
+	end.c.disconnect("d.nile", 1);
+	before.c.connect("d.nile", 1, after.c);
+	return before;
+    }
+
+    /** Make a cell's content into a span. */
+    static public Span spanify(ZZCell c0) {
+	Span sp = c0.getSpan();
+	if(sp != null) return sp;
+	
+        StringScroll sc = c0.getSpace().getStringScroll();
+	String s = c0.getText();
+        long soffs = sc.append(s);
+        sp = Span.create(
+            Address.scrollOffs(sc, soffs),
+            Address.scrollOffs(sc, soffs + s.length() - 1)
+        );
+        c0.setSpan(sp);
+	return sp;
+    }
+
+    public Nile3Part copy() {
+	check();
+	start.split(false, 1);
+	end.split(false, -1);
+	ZZCell c = start.c;
+	ZZCell first = c.N(), last = first;
+	while(true) {
+	    last.setSpan(spanify(c));
+	    if(c.equals(end.c)) break;
+	    c = c.s("d.nile");
+	    last = last.N("d.nile");
+	}
+	return new Nile3Part(
+	    new ZZCursorVirtual(first, 0),
+	    new ZZCursorVirtual(last, last.getText().length()));
+    }
+    
+    /** Return true if there's nothing before or after this. */
+    public boolean isStream() {
+	return start.end(-1) && end.end(1);
+    }
+
+    /** Check the integrity of this Nile3Part: start &lt;= end? */
+    public void check() {
+	boolean good = true;
+	if(start.c.equals(end.c)) {
+	    good = start.offs <= end.offs;
+	    p(start.offs + " " + end.offs);
+	} else {
+	    good = start.c.findCell("d.nile", 1, end.c);
+	    p(start.c + " " + end.c);
+	}
+	if(!good)
+	    throw new ZZError("Malformed Nile3Part stream! XXX");
+    }
+
+    public Object clone() { 
+	try {
+	    return super.clone(); 
+	} catch(CloneNotSupportedException e) {
+	    ZZLogger.exc(e);
+	    return null;
+	}
+    }
+}