net.sf.saxon.functions.Compare Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of saxon-he Show documentation
Show all versions of saxon-he Show documentation
An OSGi bundle for Saxon-HE
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 Saxonica Limited.
// 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.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.functions;
import net.sf.saxon.expr.Callable;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.expr.parser.ExpressionVisitor;
import net.sf.saxon.expr.sort.AtomicComparer;
import net.sf.saxon.expr.sort.GenericAtomicComparer;
import net.sf.saxon.lib.StringCollator;
import net.sf.saxon.om.Sequence;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.AtomicType;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.type.TypeHierarchy;
import net.sf.saxon.value.Int64Value;
import net.sf.saxon.value.IntegerValue;
import net.sf.saxon.value.StringValue;
/**
* This class implements the XPath 2.0 fn:compare() function
*/
// Supports string comparison using a collation
public class Compare extends CollatingFunction implements Callable {
/**
* Get the argument position (0-based) containing the collation name
* @return the position of the argument containing the collation URI
*/
@Override
protected int getCollationArgument() {
return 2;
}
/**
* For an expression that returns an integer or a sequence of integers, get
* a lower and upper bound on the values of the integers that may be returned, from
* static analysis. The default implementation returns null, meaning "unknown" or
* "not applicable". Other implementations return an array of two IntegerValue objects,
* representing the lower and upper bounds respectively. The values
* UNBOUNDED_LOWER and UNBOUNDED_UPPER are used by convention to indicate that
* the value may be arbitrarily large. The values MAX_STRING_LENGTH and MAX_SEQUENCE_LENGTH
* are used to indicate values limited by the size of a string or the size of a sequence.
*
* @return the lower and upper bounds of integer values in the result, or null to indicate
* unknown or not applicable.
*/
@Override
public IntegerValue[] getIntegerBounds() {
return new IntegerValue[] {Int64Value.MINUS_ONE, Int64Value.PLUS_ONE};
}
@Override
public void checkArguments(ExpressionVisitor visitor) throws XPathException {
super.checkArguments(visitor);
TypeHierarchy th = visitor.getConfiguration().getTypeHierarchy();
ItemType type0 = argument[0].getItemType(th);
ItemType type1 = argument[1].getItemType(th);
if (type0 instanceof AtomicType && type1 instanceof AtomicType) {
preAllocateComparer((AtomicType)type0, (AtomicType)type1, visitor.getStaticContext(), false);
}
}
/**
* Evaluate the expression
*/
/*@Nullable*/ public Int64Value evaluateItem(XPathContext context) throws XPathException {
StringValue arg0 = (StringValue)argument[0].evaluateItem(context);
StringValue arg1 = (StringValue)argument[1].evaluateItem(context);
AtomicComparer comparer = getPreAllocatedAtomicComparer();
if (comparer == null) {
comparer = getAtomicComparer(getCollator(context), context);
}
return compare(arg0, arg1, comparer);
}
private static Int64Value compare(StringValue s1, StringValue s2, AtomicComparer comparer) throws XPathException {
if (s1==null || s2==null) {
return null;
}
int result = comparer.compareAtomicValues(s1, s2);
if (result < 0) {
return Int64Value.MINUS_ONE;
} else if (result > 0) {
return Int64Value.PLUS_ONE;
} else {
return Int64Value.ZERO;
}
}
public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException {
StringValue arg0 = (StringValue)arguments[0].head();
StringValue arg1 = (StringValue)arguments[1].head();
StringCollator collator = getCollatorFromLastArgument(arguments, 2, context);
GenericAtomicComparer comparer = new GenericAtomicComparer(collator, context);
return compare(arg0, arg1, comparer);
}
}