/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 1999-2004 The Apache Software Foundation.

 *

 * Licensed 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.

 */

/*

 * $Id: XNumber.java,v 1.2.4.2 2005/09/14 20:34:46 jeffsuttor Exp $

 */

package com.sun.org.apache.xpath.internal.objects;

import com.sun.org.apache.xpath.internal.ExpressionOwner;

import com.sun.org.apache.xpath.internal.XPathContext;

import com.sun.org.apache.xpath.internal.XPathVisitor;

/**

 * This class represents an XPath number, and is capable of

 * converting the number to other types, such as a string.

 * @xsl.usage general

 */

public class XNumber extends XObject

{

    static final long serialVersionUID = -2720400709619020193L;

  /** Value of the XNumber object.

   *  @serial         */

  double m_val;

  /**

   * Construct a XNodeSet object.

   *

   * @param d Value of the object

   */

  public XNumber(double d)

  {

    super();

    m_val = d;

  }

  /**

   * Construct a XNodeSet object.

   *

   * @param num Value of the object

   */

  public XNumber(Number num)

  {

    super();

    m_val = num.doubleValue();

    setObject(num);

  }

  /**

   * Tell that this is a CLASS_NUMBER.

   *

   * @return node type CLASS_NUMBER

   */

  public int getType()

  {

    return CLASS_NUMBER;

  }

  /**

   * Given a request type, return the equivalent string.

   * For diagnostic purposes.

   *

   * @return type string "#NUMBER"

   */

  public String getTypeString()

  {

    return "#NUMBER";

  }

  /**

   * Cast result object to a number.

   *

   * @return the value of the XNumber object

   */

  public double num()

  {

    return m_val;

  }

  /**

   * Evaluate expression to a number.

   *

   * @return 0.0

   *

   * @throws javax.xml.transform.TransformerException

   */

  public double num(XPathContext xctxt)

    throws javax.xml.transform.TransformerException

  {

    return m_val;

  }

  /**

   * Cast result object to a boolean.

   *

   * @return false if the value is NaN or equal to 0.0

   */

  public boolean bool()

  {

    return (Double.isNaN(m_val) || (m_val == 0.0)) ? false : true;

  }

//  /**

//   * Cast result object to a string.

//   *

//   * @return "NaN" if the number is NaN, Infinity or -Infinity if

//   * the number is infinite or the string value of the number.

//   */

//  private static final int PRECISION = 16;

//  public String str()

//  {

//

//    if (Double.isNaN(m_val))

//    {

//      return "NaN";

//    }

//    else if (Double.isInfinite(m_val))

//    {

//      if (m_val > 0)

//        return "Infinity";

//      else

//        return "-Infinity";

//    }

//

//    long longVal = (long)m_val;

//    if ((double)longVal == m_val)

//      return Long.toString(longVal);

//

//

//    String s = Double.toString(m_val);

//    int len = s.length();

//

//    if (s.charAt(len - 2) == '.' && s.charAt(len - 1) == '0')

//    {

//      return s.substring(0, len - 2);

//    }

//

//    int exp = 0;

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

//    if (e != -1)

//    {

//      exp = Integer.parseInt(s.substring(e + 1));

//      s = s.substring(0,e);

//      len = e;

//    }

//

//    // Calculate Significant Digits:

//    // look from start of string for first digit

//    // look from end for last digit

//    // significant digits = end - start + (0 or 1 depending on decimal location)

//

//    int decimalPos = -1;

//    int start = (s.charAt(0) == '-') ? 1 : 0;

//    findStart: for( ; start < len; start++ )

//    {

//      switch (s.charAt(start))

//      {

//      case '0':

//        break;

//      case '.':

//        decimalPos = start;

//        break;

//      default:

//        break findStart;

//      }

//    }

//    int end = s.length() - 1;

//    findEnd: for( ; end > start; end-- )

//    {

//      switch (s.charAt(end))

//      {

//      case '0':

//        break;

//      case '.':

//        decimalPos = end;

//        break;

//      default:

//        break findEnd;

//      }

//    }

//

//    int sigDig = end - start;

//

//    // clarify decimal location if it has not yet been found

//    if (decimalPos == -1)

//      decimalPos = s.indexOf('.');

//

//    // if decimal is not between start and end, add one to sigDig

//    if (decimalPos < start || decimalPos > end)

//      ++sigDig;

//

//    // reduce significant digits to PRECISION if necessary

//    if (sigDig > PRECISION)

//    {

//      // re-scale BigDecimal in order to get significant digits = PRECISION

//      BigDecimal num = new BigDecimal(s);

//      int newScale = num.scale() - (sigDig - PRECISION);

//      if (newScale < 0)

//        newScale = 0;

//      s = num.setScale(newScale, BigDecimal.ROUND_HALF_UP).toString();

//

//      // remove trailing '0's; keep track of decimalPos

//      int truncatePoint = s.length();

//      while (s.charAt(--truncatePoint) == '0')

//        ;

//

//      if (s.charAt(truncatePoint) == '.')

//      {

//        decimalPos = truncatePoint;

//      }

//      else

//      {

//        decimalPos = s.indexOf('.');

//        truncatePoint += 1;

//      }

//

//      s = s.substring(0, truncatePoint);

//      len = s.length();

//    }

//

//    // Account for exponent by adding zeros as needed

//    // and moving the decimal place

//

//    if (exp == 0)

//       return s;

//

//    start = 0;

//    String sign;

//    if (s.charAt(0) == '-')

//    {

//      sign = "-";

//      start++;

//    }

//    else

//      sign = "";

//

//    String wholePart = s.substring(start, decimalPos);

//    String decimalPart = s.substring(decimalPos + 1);

//

//    // get the number of digits right of the decimal

//    int decimalLen = decimalPart.length();

//

//    if (exp >= decimalLen)

//      return sign + wholePart + decimalPart + zeros(exp - decimalLen);

//

//    if (exp > 0)

//      return sign + wholePart + decimalPart.substring(0, exp) + "."

//             + decimalPart.substring(exp);

//

//    return sign + "0." + zeros(-1 - exp) + wholePart + decimalPart;

//  }

  /**

   * Cast result object to a string.

   *

   * @return "NaN" if the number is NaN, Infinity or -Infinity if

   * the number is infinite or the string value of the number.

   */

  public String str()

  {

    if (Double.isNaN(m_val))

    {

      return "NaN";

    }

    else if (Double.isInfinite(m_val))

    {

      if (m_val > 0)

        return "Infinity";

      else

        return "-Infinity";

    }

    double num = m_val;

    String s = Double.toString(num);

    int len = s.length();

    if (s.charAt(len - 2) == '.' && s.charAt(len - 1) == '0')

    {

      s = s.substring(0, len - 2);

      if (s.equals("-0"))

        return "0";

      return s;

    }

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

    if (e < 0)

    {

      if (s.charAt(len - 1) == '0')

        return s.substring(0, len - 1);

      else

        return s;

    }

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

    String sign;

    if (s.charAt(0) == '-')

    {

      sign = "-";

      s = s.substring(1);

      --e;

    }

    else

      sign = "";

    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

   */

  static private String zeros(int n)

  {

    if (n < 1)

      return "";

    char[] buf = new char[n];

    for (int i = 0; i < n; i++)

    {

      buf[i] = '0';

    }

    return new String(buf);

  }

  /**

   * Return a java object that's closest to the representation

   * that should be handed to an extension.

   *

   * @return The value of this XNumber as a Double object

   */

  public Object object()

  {

    if(null == m_obj)

      setObject(new Double(m_val));

    return m_obj;

  }

  /**

   * Tell if two objects are functionally equal.

   *

   * @param obj2 Object to compare this to

   *

   * @return true if the two objects are equal

   *

   * @throws javax.xml.transform.TransformerException

   */

  public boolean equals(XObject obj2)

  {

    // In order to handle the 'all' semantics of

    // nodeset comparisons, we always call the

    // nodeset function.

    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(javax.xml.transform.TransformerException te)

    {

      throw new com.sun.org.apache.xml.internal.utils.WrappedRuntimeException(te);

    }

  }

  /**

   * Tell if this expression returns a stable number that will not change during

   * iterations within the expression.  This is used to determine if a proximity

   * position predicate can indicate that no more searching has to occur.

   *

   *

   * @return true if the expression represents a stable number.

   */

  public boolean isStableNumber()

  {

    return true;

  }

  /**

   * @see com.sun.org.apache.xpath.internal.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)

   */

  public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)

  {

        visitor.visitNumberLiteral(owner, this);

  }

}