- /*
- * 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: ExsltMath.java,v 1.12 2004/02/11 17:56:36 minchau Exp $
- */
- package com.sun.org.apache.xalan.internal.lib;
-
- import com.sun.org.apache.xpath.internal.NodeSet;
-
- import org.w3c.dom.Node;
- import org.w3c.dom.NodeList;
-
- /**
- * This class contains EXSLT math extension functions.
- * It is accessed by specifying a namespace URI as follows:
- * <pre>
- * xmlns:math="http://exslt.org/math"
- * </pre>
- *
- * The documentation for each function has been copied from the relevant
- * EXSLT Implementer page.
- *
- * @see <a href="http://www.exslt.org/">EXSLT</a>
-
- * @xsl.usage general
- */
- public class ExsltMath extends ExsltBase
- {
- // Constants
- private static String PI = "3.1415926535897932384626433832795028841971693993751";
- private static String E = "2.71828182845904523536028747135266249775724709369996";
- private static String SQRRT2 = "1.41421356237309504880168872420969807856967187537694";
- private static String LN2 = "0.69314718055994530941723212145817656807550013436025";
- private static String LN10 = "2.302585092994046";
- private static String LOG2E = "1.4426950408889633";
- private static String SQRT1_2 = "0.7071067811865476";
-
- /**
- * The math:max function returns the maximum value of the nodes passed as the argument.
- * The maximum value is defined as follows. The node set passed as an argument is sorted
- * in descending order as it would be by xsl:sort with a data type of number. The maximum
- * is the result of converting the string value of the first node in this sorted list to
- * a number using the number function.
- * <p>
- * If the node set is empty, or if the result of converting the string values of any of the
- * nodes to a number is NaN, then NaN is returned.
- *
- * @param nl The NodeList for the node-set to be evaluated.
- *
- * @return the maximum value found, NaN if any node cannot be converted to a number.
- *
- * @see <a href="http://www.exslt.org/">EXSLT</a>
- */
- public static double max (NodeList nl)
- {
- if (nl == null || nl.getLength() == 0)
- return Double.NaN;
-
- double m = - Double.MAX_VALUE;
- for (int i = 0; i < nl.getLength(); i++)
- {
- Node n = nl.item(i);
- double d = toNumber(n);
- if (Double.isNaN(d))
- return Double.NaN;
- else if (d > m)
- m = d;
- }
-
- return m;
- }
-
- /**
- * The math:min function returns the minimum value of the nodes passed as the argument.
- * The minimum value is defined as follows. The node set passed as an argument is sorted
- * in ascending order as it would be by xsl:sort with a data type of number. The minimum
- * is the result of converting the string value of the first node in this sorted list to
- * a number using the number function.
- * <p>
- * If the node set is empty, or if the result of converting the string values of any of
- * the nodes to a number is NaN, then NaN is returned.
- *
- * @param nl The NodeList for the node-set to be evaluated.
- *
- * @return the minimum value found, NaN if any node cannot be converted to a number.
- *
- * @see <a href="http://www.exslt.org/">EXSLT</a>
- */
- public static double min (NodeList nl)
- {
- if (nl == null || nl.getLength() == 0)
- return Double.NaN;
-
- double m = Double.MAX_VALUE;
- for (int i = 0; i < nl.getLength(); i++)
- {
- Node n = nl.item(i);
- double d = toNumber(n);
- if (Double.isNaN(d))
- return Double.NaN;
- else if (d < m)
- m = d;
- }
-
- return m;
- }
-
- /**
- * The math:highest function returns the nodes in the node set whose value is the maximum
- * value for the node set. The maximum value for the node set is the same as the value as
- * calculated by math:max. A node has this maximum value if the result of converting its
- * string value to a number as if by the number function is equal to the maximum value,
- * where the equality comparison is defined as a numerical comparison using the = operator.
- * <p>
- * If any of the nodes in the node set has a non-numeric value, the math:max function will
- * return NaN. The definition numeric comparisons entails that NaN != NaN. Therefore if any
- * of the nodes in the node set has a non-numeric value, math:highest will return an empty
- * node set.
- *
- * @param nl The NodeList for the node-set to be evaluated.
- *
- * @return node-set with nodes containing the maximum value found, an empty node-set
- * if any node cannot be converted to a number.
- */
- public static NodeList highest (NodeList nl)
- {
- double maxValue = max(nl);
-
- NodeSet highNodes = new NodeSet();
- highNodes.setShouldCacheNodes(true);
-
- if (Double.isNaN(maxValue))
- return highNodes; // empty Nodeset
-
- for (int i = 0; i < nl.getLength(); i++)
- {
- Node n = nl.item(i);
- double d = toNumber(n);
- if (d == maxValue)
- highNodes.addElement(n);
- }
- return highNodes;
- }
-
- /**
- * The math:lowest function returns the nodes in the node set whose value is the minimum value
- * for the node set. The minimum value for the node set is the same as the value as calculated
- * by math:min. A node has this minimum value if the result of converting its string value to
- * a number as if by the number function is equal to the minimum value, where the equality
- * comparison is defined as a numerical comparison using the = operator.
- * <p>
- * If any of the nodes in the node set has a non-numeric value, the math:min function will return
- * NaN. The definition numeric comparisons entails that NaN != NaN. Therefore if any of the nodes
- * in the node set has a non-numeric value, math:lowest will return an empty node set.
- *
- * @param nl The NodeList for the node-set to be evaluated.
- *
- * @return node-set with nodes containing the minimum value found, an empty node-set
- * if any node cannot be converted to a number.
- *
- */
- public static NodeList lowest (NodeList nl)
- {
- double minValue = min(nl);
-
- NodeSet lowNodes = new NodeSet();
- lowNodes.setShouldCacheNodes(true);
-
- if (Double.isNaN(minValue))
- return lowNodes; // empty Nodeset
-
- for (int i = 0; i < nl.getLength(); i++)
- {
- Node n = nl.item(i);
- double d = toNumber(n);
- if (d == minValue)
- lowNodes.addElement(n);
- }
- return lowNodes;
- }
-
- /**
- * The math:abs function returns the absolute value of a number.
- *
- * @param num A number
- * @return The absolute value of the number
- */
- public static double abs(double num)
- {
- return Math.abs(num);
- }
-
- /**
- * The math:acos function returns the arccosine value of a number.
- *
- * @param num A number
- * @return The arccosine value of the number
- */
- public static double acos(double num)
- {
- return Math.acos(num);
- }
-
- /**
- * The math:asin function returns the arcsine value of a number.
- *
- * @param num A number
- * @return The arcsine value of the number
- */
- public static double asin(double num)
- {
- return Math.asin(num);
- }
-
- /**
- * The math:atan function returns the arctangent value of a number.
- *
- * @param num A number
- * @return The arctangent value of the number
- */
- public static double atan(double num)
- {
- return Math.atan(num);
- }
-
- /**
- * The math:atan2 function returns the angle ( in radians ) from the X axis to a point (y,x).
- *
- * @param num1 The X axis value
- * @param num2 The Y axis value
- * @return The angle (in radians) from the X axis to a point (y,x)
- */
- public static double atan2(double num1, double num2)
- {
- return Math.atan2(num1, num2);
- }
-
- /**
- * The math:cos function returns cosine of the passed argument.
- *
- * @param num A number
- * @return The cosine value of the number
- */
- public static double cos(double num)
- {
- return Math.cos(num);
- }
-
- /**
- * The math:exp function returns e (the base of natural logarithms) raised to a power.
- *
- * @param num A number
- * @return The value of e raised to the given power
- */
- public static double exp(double num)
- {
- return Math.exp(num);
- }
-
- /**
- * The math:log function returns the natural logarithm of a number.
- *
- * @param num A number
- * @return The natural logarithm of the number
- */
- public static double log(double num)
- {
- return Math.log(num);
- }
-
- /**
- * The math:power function returns the value of a base expression taken to a specified power.
- *
- * @param num1 The base
- * @param num2 The power
- * @return The value of the base expression taken to the specified power
- */
- public static double power(double num1, double num2)
- {
- return Math.pow(num1, num2);
- }
-
- /**
- * The math:random function returns a random number from 0 to 1.
- *
- * @return A random double from 0 to 1
- */
- public static double random()
- {
- return Math.random();
- }
-
- /**
- * The math:sin function returns the sine of the number.
- *
- * @param num A number
- * @return The sine value of the number
- */
- public static double sin(double num)
- {
- return Math.sin(num);
- }
-
- /**
- * The math:sqrt function returns the square root of a number.
- *
- * @param num A number
- * @return The square root of the number
- */
- public static double sqrt(double num)
- {
- return Math.sqrt(num);
- }
-
- /**
- * The math:tan function returns the tangent of the number passed as an argument.
- *
- * @param num A number
- * @return The tangent value of the number
- */
- public static double tan(double num)
- {
- return Math.tan(num);
- }
-
- /**
- * The math:constant function returns the specified constant to a set precision.
- * The possible constants are:
- * <pre>
- * PI
- * E
- * SQRRT2
- * LN2
- * LN10
- * LOG2E
- * SQRT1_2
- * </pre>
- * @param name The name of the constant
- * @param precision The precision
- * @return The value of the specified constant to the given precision
- */
- public static double constant(String name, double precision)
- {
- String value = null;
- if (name.equals("PI"))
- value = PI;
- else if (name.equals("E"))
- value = E;
- else if (name.equals("SQRRT2"))
- value = SQRRT2;
- else if (name.equals("LN2"))
- value = LN2;
- else if (name.equals("LN10"))
- value = LN10;
- else if (name.equals("LOG2E"))
- value = LOG2E;
- else if (name.equals("SQRT1_2"))
- value = SQRT1_2;
-
- if (value != null)
- {
- int bits = new Double(precision).intValue();
-
- if (bits <= value.length())
- value = value.substring(0, bits);
-
- return new Double(value).doubleValue();
- }
- else
- return Double.NaN;
-
- }
-
- }