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Java/clang/flowing/StackFrame.java

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+/*   
+StackFrame.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.flowing;
+import org.gzigzag.*;
+
+/** A stack frame for Flowing Clang.
+ */
+
+public abstract class StackFrame {
+String rcsid = "$Id: StackFrame.java,v 1.5 2000/11/16 20:33:13 bfallenstein Exp $";
+    public static boolean dbg = true;
+    static final void p(String s) { if(dbg) ZZLogger.log(s); }
+
+    // METHODS TO BE IMPLEMENTED BY SUBCLASSES
+
+    /** Get the value associated with a cell. */
+    public abstract Object getSingle(ZZCell c);
+
+    /** Set the value associated with a cell.
+     *  @param d	The Data object in which the value to be set is found.
+     *  @param at	The value's position in the Data object.
+     */
+    public abstract void setSingle(ZZCell c, Data d, int at);
+
+    /** Get position of instruction pointer. */
+    public abstract ZZCell getPos();
+    /** Set position of instruction pointer. */
+    public abstract void setPos(ZZCell c);
+
+    /** Create a lower-level stackframe. */
+    public abstract StackFrame call();
+
+    /** Return true if this stack frame is parent of given stack frame. */
+    public abstract boolean parentof(StackFrame sf);
+
+    /** Return to the next higher stackframe (disconnects this (lower) frame).
+     *  Also sets instruction pointer to null, but keeps the values associated
+     *  with cells, so that the returned data can be read. Call delete() when
+     *  you're done with the values.
+     */
+    public abstract StackFrame ret();
+
+    /** Delete the cells associated with the stackframe, if any.
+     *  This renders the values of a structural stackframe inaccessible.
+     */
+    public void delete() {}
+
+    // METHODS StackFrame PROVIDES
+
+    private static final ZZCell[] reverse(ZZCell[] arr) {
+	ZZCell[] res = new ZZCell[arr.length];
+	for(int i=0; i<arr.length; i++) res[arr.length-i-1] = arr[i];
+	return res;
+    }
+
+    public Data get(ZZCell c, int dir) {
+	p("Start getting for "+c.getText()+" ("+c.getID()+")");
+	ZZCell[] cells = c.readRank("d.1", dir, false);
+	if(dir<0) cells = reverse(cells);
+	Object[] result = new Object[cells.length];
+	p("Getting "+cells.length+" values");
+	for(int i=0; i<cells.length; i++) {
+	    if(cells[i].s("d.clone", -1) != null) {
+		p("Getting: " + cells[i].getText());
+		result[i] = getSingle(cells[i].getRootclone());
+		if(result[i] == null)
+		    throw new ZZError("Value for " + cells[i].getText() +
+				      " not yet set");
+	    } else {
+		p("Getting literal");
+		result[i] = cells[i];
+	    }
+	    p("Got "+result[i]);
+	}
+	p("Finish getting");
+	return new Data(result);
+    }
+		
+    public void put(ZZCell c, Data params, int dir) {
+	p("Start putting for "+c.getText()+" ("+c.getID()+")");
+	Data pars = params != null ? params : new Data();
+	ZZCell[] cells = c.readRank("d.1", dir, false);
+	if(dir<0) cells = reverse(cells);
+	p("Putting "+cells.length+" values");
+	if(pars.len() < cells.length)
+	    throw new ZZError("Pars: " + pars.len() +
+			      " < cells: " + cells.length);
+	for(int i=0; i<cells.length; i++) {
+	    p("Putting: "+pars.s(i)+" into: "+cells[i].getText());
+	    setSingle(cells[i].getRootclone(), pars, i);
+	}
+	p("Finish putting");
+    }
+
+}
+
+