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The XPath engine used by HtmlUnit.
There is a newer version: 4.7.0
/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.htmlunit.xpath.objects;

import org.htmlunit.xpath.XPathContext;
import org.htmlunit.xpath.XPathVisitor;

/**
 * This class represents an XPath number, and is capable of converting the number to other types,
 * such as a string.
 */
public class XNumber extends XObject {

  /**
   * Value of the XNumber object.
   *
   * @serial
   */
  final double m_val;

  /**
   * Construct a XNodeSet object.
   *
   * @param d Value of the object
   */
  public XNumber(final double d) {
    super();

    m_val = d;
  }

  /** {@inheritDoc} */
  @Override
  public int getType() {
    return CLASS_NUMBER;
  }

  /** {@inheritDoc} */
  @Override
  public String getTypeString() {
    return "#NUMBER";
  }

  /** {@inheritDoc} */
  @Override
  public double num() {
    return m_val;
  }

  /** {@inheritDoc} */
  @Override
  public double num(final XPathContext xctxt) throws javax.xml.transform.TransformerException {

    return m_val;
  }

  /** {@inheritDoc} */
  @Override
  public boolean bool() {
    return !Double.isNaN(m_val) && (m_val != 0.0);
  }

  /** {@inheritDoc} */
  @Override
  public String str() {

    if (Double.isNaN(m_val)) {
      return "NaN";
    }
    else if (Double.isInfinite(m_val)) {
      if (m_val > 0) {
        return "Infinity";
      }
      return "-Infinity";
    }

    String s = Double.toString(m_val);
    final int len = s.length();

    if (s.charAt(len - 2) == '.' && s.charAt(len - 1) == '0') {
      s = s.substring(0, len - 2);

      if ("-0".equals(s)) {
          return "0";
      }

      return s;
    }

    int e = s.indexOf('E');

    if (e < 0) {
      if (s.charAt(len - 1) == '0') {
        return s.substring(0, len - 1);
      }
      return s;
    }

    final int exp = Integer.parseInt(s.substring(e + 1));
    final String sign;

    if (s.charAt(0) == '-') {
      sign = "-";
      s = s.substring(1);

      --e;
    }
    else {
        sign = "";
    }

    final int nDigits = e - 2;

    if (exp >= nDigits) {
        return sign + s.substring(0, 1) + s.substring(2, e) + zeros(exp - nDigits);
    }

    // Eliminate trailing 0's - bugzilla 14241
    while (s.charAt(e - 1) == '0') {
        e--;
    }

    if (exp > 0) {
      return sign + s.substring(0, 1) + s.substring(2, 2 + exp) + "." + s.substring(2 + exp, e);
    }

    return sign + "0." + zeros(-1 - exp) + s.substring(0, 1) + s.substring(2, e);
  }

  /**
   * Return a string of '0' of the given length
   *
   * @param n Length of the string to be returned
   * @return a string of '0' with the given length
   */
  private static String zeros(final int n) {
    if (n < 1) {
        return "";
    }

    final char[] buf = new char[n];

    for (int i = 0; i < n; i++) {
      buf[i] = '0';
    }

    return new String(buf);
  }

  /** {@inheritDoc} */
  @Override
  public Object object() {
    if (null == m_obj) {
        setObject(new Double(m_val));
    }
    return m_obj;
  }

  /** {@inheritDoc} */
  @Override
  public boolean equals(final XObject obj2) {

    // In order to handle the 'all' semantics of
    // nodeset comparisons, we always call the
    // nodeset function.
    final int t = obj2.getType();
    try {
      if (t == XObject.CLASS_NODESET) {
          return obj2.equals(this);
      }
      else if (t == XObject.CLASS_BOOLEAN) {
          return obj2.bool() == bool();
      }
      else {
          return m_val == obj2.num();
      }
    }
    catch (final javax.xml.transform.TransformerException te) {
      throw new org.htmlunit.xpath.xml.utils.WrappedRuntimeException(te);
    }
  }

  /** {@inheritDoc} */
  @Override
  public boolean isStableNumber() {
    return true;
  }

  /** {@inheritDoc} */
  @Override
  public void callVisitors(final XPathVisitor visitor) {
    visitor.visitNumberLiteral();
  }
}