package client.net.sf.saxon.ce.functions;
import client.net.sf.saxon.ce.expr.Expression;
import client.net.sf.saxon.ce.expr.ExpressionVisitor;
import client.net.sf.saxon.ce.expr.XPathContext;
import client.net.sf.saxon.ce.om.Item;
import client.net.sf.saxon.ce.trans.XPathException;
import client.net.sf.saxon.ce.type.*;
import client.net.sf.saxon.ce.value.*;
import client.net.sf.saxon.ce.value.StringValue;
/**
* Implements the XPath number() function.
*/
public class NumberFn extends SystemFunction {
public NumberFn newInstance() {
return new NumberFn();
}
/**
* Simplify and validate.
* This is a pure function so it can be simplified in advance if the arguments are known
* @param visitor an expression visitor
*/
public Expression simplify(ExpressionVisitor visitor) throws XPathException {
useContextItemAsDefault();
argument[0].setFlattened(true);
return simplifyArguments(visitor);
}
/**
* Type-check the expression. This also calls preEvaluate() to evaluate the function
* if all the arguments are constant; functions that do not require this behavior
* can override the preEvaluate method.
*/
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException {
Expression e2 = super.typeCheck(visitor, contextItemType);
if (e2 != this) {
return e2;
}
if (argument[0] instanceof NumberFn) {
// happens through repeated rewriting
argument[0] = ((NumberFn)argument[0]).argument[0];
}
return this;
}
/**
* Evaluate in a general context
*/
public Item evaluateItem(XPathContext context) throws XPathException {
Item arg0 = argument[0].evaluateItem(context);
if (arg0==null) {
return DoubleValue.NaN;
}
if (arg0 instanceof BooleanValue || arg0 instanceof NumericValue) {
ConversionResult result = ((AtomicValue)arg0).convert(BuiltInAtomicType.DOUBLE, true);
if (result instanceof ValidationFailure) {
return DoubleValue.NaN;
} else {
return (AtomicValue)result;
}
}
if (arg0 instanceof StringValue && !(arg0 instanceof AnyURIValue)) {
CharSequence s = arg0.getStringValueCS();
try {
return new DoubleValue(StringToDouble.stringToNumber(s));
} catch (NumberFormatException e) {
return DoubleValue.NaN;
}
}
return DoubleValue.NaN;
}
/**
* Static method to perform the same conversion as the number() function. This is different from the
* convert(Type.DOUBLE) in that it produces NaN rather than an error for non-numeric operands.
* @param value the value to be converted
* @return the result of the conversion
*/
public static DoubleValue convert(AtomicValue value) {
try {
if (value==null) {
return DoubleValue.NaN;
}
if (value instanceof BooleanValue || value instanceof NumericValue) {
ConversionResult result = value.convert(BuiltInAtomicType.DOUBLE, true);
if (result instanceof ValidationFailure) {
return DoubleValue.NaN;
} else {
return (DoubleValue)result;
}
}
if (value instanceof StringValue && !(value instanceof AnyURIValue)) {
double d = StringToDouble.stringToNumber(value.getStringValueCS());
return new DoubleValue(d);
}
return DoubleValue.NaN;
} catch (NumberFormatException e) {
return DoubleValue.NaN;
}
}
}
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is “Incompatible With Secondary Licenses”, as defined by the Mozilla Public License, v. 2.0.