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The Apache Commons Codec package contains simple encoder and decoders for various formats such as Base64 and Hexadecimal. In addition to these widely used encoders and decoders, the codec package also maintains a collection of phonetic encoding utilities.

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/*
* Copyright (c) 2005, Graph Builder
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * 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.
*
* * Neither the name of Graph Builder nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.

* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/

package com.graphbuilder.math;

import com.graphbuilder.struc.Bag;

/**
A node of an expression tree that represents a function.  A FuncNode can have 0 or more children.
*/
public class FuncNode extends TermNode {

	private Bag bag = new Bag(1);
	private double[] of = new double[1];

	public FuncNode(String name, boolean negate) {
		super(name, negate);
	}

	/**
	Adds the expression as a child.
	*/
	public void add(Expression x) {
		insert(x, bag.size());
	}

	/**
	Adds the expression as a child at the specified index.
	*/
	public void insert(Expression x, int i) {
		checkBeforeAccept(x);
		int oldCap = bag.getCapacity();
		bag.insert(x, i);
		int newCap = bag.getCapacity();

		if (oldCap != newCap)
			of = new double[newCap];

		x.parent = this;
	}

	/**
	Removes the specified expression as a child.  Does nothing if the expression was not a child.
	*/
	public void remove(Expression x) {
		int size = bag.size();
		bag.remove(x);
		if (size != bag.size())
			x.parent = null;
	}

	/**
	Returns the number of child expressions.
	*/
	public int numChildren() {
		return bag.size();
	}

	/**
	Returns the child expression at the specified index.
	*/
	public Expression child(int i) {
		return (Expression) bag.get(i);
	}

	/**
	Evaluates each of the children, storing the result in an internal double array.  The FuncMap is
	used to obtain a Function object based on the name of this FuncNode.  The function is passed
	the double array and returns a result.  If negate is true, the result is negated.  The result
	is then returned.  The numParam passed to the function is the number of children of this FuncNode.
	*/
	public double eval(VarMap v, FuncMap f) {
		int numParam = bag.size();

		for (int i = 0; i < numParam; i++)
			of[i] = child(i).eval(v, f);

		double result = f.getFunction(name, numParam).of(of, numParam);

		if (negate) result = -result;

		return result;
	}
}