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Java > Open Source Codes > net > sf > saxon > functions > Rounding


1 package net.sf.saxon.functions;
2 import net.sf.saxon.expr.Token;
3 import net.sf.saxon.expr.XPathContext;
4 import net.sf.saxon.om.Item;
5 import net.sf.saxon.trans.XPathException;
6 import net.sf.saxon.value.AtomicValue;
7 import net.sf.saxon.value.IntegerValue;
8 import net.sf.saxon.value.NumericValue;
9
10 /**
11 * This class supports the ceiling(), floor(), round(), and round-to-half-even() functions,
12  * and also the abs() function
13 */
14
15 public final class Rounding extends SystemFunction {
16
17     public static final int FLOOR = 0;
18     public static final int CEILING = 1;
19     public static final int ROUND = 2;
20     public static final int HALF_EVEN = 3;
21     public static final int ABS = 4;
22
23     /**
24     * Evaluate the function
25     */
26
27     public Item evaluateItem(XPathContext context) throws XPathException {
28
29         AtomicValue val0 = (AtomicValue)argument[0].evaluateItem(context);
30         if (val0==null) return null;
31         NumericValue val = (NumericValue)val0.getPrimitiveValue();
32
33         switch (operation) {
34             case FLOOR:
35                 return val.floor();
36             case CEILING:
37                 return val.ceiling();
38             case ROUND:
39                 return val.round();
40             case HALF_EVEN:
41                 int scale = 0;
42                 if (argument.length==2) {
43                     AtomicValue scaleVal0 = (AtomicValue)argument[1].evaluateItem(context);
44                     NumericValue scaleVal = (NumericValue)scaleVal0.getPrimitiveValue();
45                     scale = (int)scaleVal.longValue();
46                 }
47                 return val.roundToHalfEven(scale);
48             case ABS:
49                 double sign = val.signum();
50                 if (sign < 0) {
51                     return val.negate();
52                 } else if (sign == 0) {
53                     // ensure that the result is positive zero
54 return val.arithmetic(Token.PLUS, IntegerValue.ZERO, context);
55                 } else {
56                     return val;
57                 }
58             default:
59                 throw new UnsupportedOperationException JavaDoc("Unknown rounding function");
60         }
61     }
62
63 }
64
65
66 //
67 // The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
68 // you may not use this file except in compliance with the License. You may obtain a copy of the
69 // License at http://www.mozilla.org/MPL/
70 //
71 // Software distributed under the License is distributed on an "AS IS" basis,
72 // WITHOUT WARRANTY OF ANY KIND, either express or implied.
73 // See the License for the specific language governing rights and limitations under the License.
74 //
75 // The Original Code is: all this file.
76 //
77 // The Initial Developer of the Original Code is Michael H. Kay.
78 //
79 // Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
80 //
81 // Contributor(s): none.
82 //
83
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