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From-SVN: r102074

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diff --git a/libjava/classpath/gnu/xml/xpath/LangFunction.java b/libjava/classpath/gnu/xml/xpath/LangFunction.java
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+/* LangFunction.java -- 
+   Copyright (C) 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package gnu.xml.xpath;
+
+import java.util.List;
+import javax.xml.namespace.QName;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+
+/**
+ * The <code>lang</code> function returns true or false depending on whether
+ * the language of the context node as specified by xml:lang attributes is
+ * the same as or is a sublanguage of the language specified by the argument
+ * string. The language of the context node is determined by the value of
+ * the xml:lang attribute on the context node, or, if the context node has
+ * no xml:lang attribute, by the value of the xml:lang attribute on the
+ * nearest ancestor of the context node that has an xml:lang attribute. If
+ * there is no such attribute, then lang returns false. If there is such an
+ * attribute, then lang returns true if the attribute value is equal to the
+ * argument ignoring case, or if there is some suffix starting with - such
+ * that the attribute value is equal to the argument ignoring that suffix of
+ * the attribute value and ignoring case.
+ *
+ * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
+ */
+final class LangFunction
+  extends Expr
+{
+
+  final Expr arg;
+
+  LangFunction(List args)
+  {
+    this((Expr) args.get(0));
+  }
+
+  LangFunction(Expr arg)
+  {
+    this.arg = arg;
+  }
+
+  public Object evaluate(Node context, int pos, int len)
+  {
+    Object val = arg.evaluate(context, pos, len);
+    String lang = _string(context, val);
+    String clang = getLang(context);
+    while (clang == null && context != null)
+      {
+        context = context.getParentNode();
+        clang = getLang(context);
+      }
+    boolean ret = (clang == null) ? false :
+      clang.toLowerCase().startsWith(lang.toLowerCase());
+    return ret ? Boolean.TRUE : Boolean.FALSE;
+  }
+
+  String getLang(Node node)
+  {
+    if (node.getNodeType() == Node.ELEMENT_NODE)
+      {
+        return ((Element) node).getAttribute("xml:lang");
+      }
+    return null;
+  }
+  
+  public Expr clone(Object context)
+  {
+    return new IdFunction(arg.clone(context));
+  }
+
+  public boolean references(QName var)
+  {
+    return arg.references(var);
+  }
+
+  public String toString()
+  {
+    return "lang(" + arg + ")";
+  }
+  
+}