StackOperator.java

// Copyright 2001, FreeHEP.
package org.freehep.postscript;

/**
 * Stack Operators for PostScript Processor
 *
 * @author Mark Donszelmann
 * @version $Id: StackOperator.java 8958 2006-09-12 23:37:43Z duns $
 */
public class StackOperator extends PSOperator {
    
    public static Class[] operators = {
        Pop.class, Exch.class, Dup.class, Index.class,
        Roll.class, Clear.class, Count.class,
        Mark.class, ClearToMark.class, CountToMark.class
    };

    public boolean execute(OperandStack os) {
        throw new RuntimeException("Cannot execute class: "+getClass());
    }
}

class Pop extends StackOperator {
    { operandTypes = new Class[] {PSObject.class}; }

    public boolean execute(OperandStack os) {
        os.pop();
        return true;
    }
}

class Exch extends StackOperator {
    { operandTypes = new Class[] {PSObject.class, PSObject.class}; }

    public boolean execute(OperandStack os) {
        os.exch();
        return true;
    }
}

class Dup extends StackOperator {
    { operandTypes = new Class[] {PSObject.class}; }

    public boolean execute(OperandStack os) {
        os.dup();
        return true;
    }
}

class Index extends StackOperator {
    { operandTypes = new Class[] {PSInteger.class}; }

    public boolean execute(OperandStack os) {
        int n = os.popInteger().getValue();
        if ((n < 0) || (n > os.size())) {
            error(os, new RangeCheck());
        } else {
            os.index(n);
        }
        return true;
    }
}

class Roll extends StackOperator {
    { operandTypes = new Class[] {PSInteger.class, PSInteger.class}; }

    public boolean execute(OperandStack os) {
        PSInteger j = os.popInteger();
        PSInteger n = os.popInteger();
        
        if (n.getValue() == 0) {
            // ignore
            return true;
        } else if ((n.getValue() < 0) || (Math.abs(j.getValue()) > n.getValue())) {
            error(os, new RangeCheck());
        } else if (n.getValue() > os.size()) {
            error(os, new StackUnderflow());
        } else {    
            os.roll(n.getValue(), j.getValue());
        }
        return true;
    }
}

class Clear extends StackOperator {

    public boolean execute(OperandStack os) {
        os.clear();
        return true;
    }
}

class Count extends StackOperator {

    public boolean execute(OperandStack os) {
        os.push(os.size());
        return true;
    }
}

class Mark extends StackOperator {

    public boolean execute(OperandStack os) {
        os.push(new PSMark());
        return true;
    }
}

class ClearToMark extends StackOperator {

    public boolean execute(OperandStack os) {
        if (!os.clearToMark()) {
            error(os, new UnmatchedMark());
        }
        return true;
    }
}

class CountToMark extends StackOperator {

    public boolean execute(OperandStack os) {
        int n = os.countToMark();
        if (n < 0) {
            error(os, new UnmatchedMark());
        } else {
            os.push(n);
        }
        return true;
    }
}