//
// Compiler.cs
//
// Authors:
//	Ben Maurer (bmaurer@users.sourceforge.net)
//	Atsushi Enomoto (ginga@kit.hi-ho.ne.jp)
//	
// (C) 2003 Ben Maurer
// (C) 2003 Atsushi Enomoto
//

//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.Collections;
using System.Security.Policy;
using System.Xml;
using System.Xml.XPath;
using System.Xml.Xsl;
using System.IO;

using Mono.Xml.Xsl.Operations;
using Mono.Xml.XPath;

using QName = System.Xml.XmlQualifiedName;

namespace Mono.Xml.Xsl 
{
	internal class CompiledStylesheet {
		XslStylesheet style;
		Hashtable globalVariables;
		Hashtable attrSets;
		XmlNamespaceManager nsMgr;
		Hashtable keys;
		Hashtable outputs;
		Hashtable decimalFormats;
		MSXslScriptManager msScripts;
		
		public CompiledStylesheet (XslStylesheet style, Hashtable globalVariables, Hashtable attrSets, XmlNamespaceManager nsMgr, Hashtable keys, Hashtable outputs, Hashtable decimalFormats,
			MSXslScriptManager msScripts)
		{
			this.style = style;
			this.globalVariables = globalVariables;
			this.attrSets = attrSets;
			this.nsMgr = nsMgr;
			this.keys = keys;
			this.outputs = outputs;
			this.decimalFormats = decimalFormats;
			this.msScripts = msScripts;
		}
		public Hashtable Variables {get{return globalVariables;}}
		public XslStylesheet Style { get { return style; }}
		public XmlNamespaceManager NamespaceManager {get{return nsMgr;}}
		public Hashtable Keys {get { return keys;}}
		public Hashtable Outputs { get { return outputs; }}
		
		public MSXslScriptManager ScriptManager {
			get { return msScripts; }
		}
		
		
		public XslDecimalFormat LookupDecimalFormat (QName name)
		{
			XslDecimalFormat ret = decimalFormats [name] as XslDecimalFormat;
			if (ret == null && name == QName.Empty)
				return XslDecimalFormat.Default;
			return ret;
		}
		
		public XslGeneralVariable ResolveVariable (QName name)
		{
			return (XslGeneralVariable)globalVariables [name];
		}
		
		public ArrayList ResolveKey (QName name)
		{
			return (ArrayList) keys [name];
		}
		
		public XslAttributeSet ResolveAttributeSet (QName name)
		{
			return (XslAttributeSet)attrSets [name];
		}
	}
	
	internal class Compiler : IStaticXsltContext {
		public const string XsltNamespace = "http://www.w3.org/1999/XSL/Transform";
			
		ArrayList inputStack = new ArrayList ();
		XPathNavigator currentInput;
		
		Stack styleStack = new Stack ();
		XslStylesheet currentStyle;
		
		Hashtable keys = new Hashtable ();
		Hashtable globalVariables = new Hashtable ();
		Hashtable attrSets = new Hashtable ();
	
		XmlNamespaceManager nsMgr = new XmlNamespaceManager (new NameTable ());
				
		XmlResolver res;
		Evidence evidence;

		XslStylesheet rootStyle;
		Hashtable outputs = new Hashtable ();
		bool keyCompilationMode;	
		string stylesheetVersion;
		XsltDebuggerWrapper debugger;

		public Compiler (object debugger)
		{
			if (debugger != null)
				this.debugger = new XsltDebuggerWrapper (debugger);
		}

		public XsltDebuggerWrapper Debugger {
			get { return debugger; }
		}

		public void CheckExtraAttributes (string element, params string [] validNames)
		{
			if (Input.MoveToFirstAttribute ()) {
				do {
					if (Input.NamespaceURI.Length > 0)
						continue;
					bool valid = false;
					foreach (string s in validNames)
						if (Input.LocalName == s) {
							valid = true;
							continue;
						}
					if (!valid)
						throw new XsltCompileException (String.Format ("Invalid attribute '{0}' on element '{1}'", Input.LocalName, element), null, Input);
				} while (Input.MoveToNextAttribute ());
				Input.MoveToParent ();
			}
		}

		public CompiledStylesheet Compile (XPathNavigator nav, XmlResolver res, Evidence evidence)
		{
			this.xpathParser = new XPathParser (this);
			this.patternParser = new XsltPatternParser (this);
			this.res = res;
			if (res == null)
				this.res = new XmlUrlResolver ();
			this.evidence = evidence;

			// reject empty document.
			if (nav.NodeType == XPathNodeType.Root && !nav.MoveToFirstChild ())
				throw new XsltCompileException ("Stylesheet root element must be either \"stylesheet\" or \"transform\" or any literal element", null, nav);
			while (nav.NodeType != XPathNodeType.Element) nav.MoveToNext();
			
			stylesheetVersion = nav.GetAttribute ("version", 
				(nav.NamespaceURI != XsltNamespace) ?
				XsltNamespace : String.Empty);
			outputs [""] = new XslOutput ("", stylesheetVersion);
				
			PushInputDocument (nav);
			if (nav.MoveToFirstNamespace (XPathNamespaceScope.ExcludeXml))
			{
				do {
					nsMgr.AddNamespace (nav.LocalName, nav.Value);
				} while (nav.MoveToNextNamespace (XPathNamespaceScope.ExcludeXml));
				nav.MoveToParent ();
			}
			try {
				rootStyle = new XslStylesheet ();
				rootStyle.Compile (this);
			} catch (XsltCompileException) {
				throw;
			} catch (Exception x) {
				throw new XsltCompileException ("XSLT compile error. " + x.Message, x,  Input);
			}
			
			return new CompiledStylesheet (rootStyle, globalVariables, attrSets, nsMgr, keys, outputs, decimalFormats, msScripts);
		}
		
		MSXslScriptManager msScripts = new MSXslScriptManager ();
		public MSXslScriptManager ScriptManager {
			get { return msScripts; }
		}

		public bool KeyCompilationMode {
			get { return keyCompilationMode; }
			set { keyCompilationMode = value; }
		}

		internal Evidence Evidence {
			get { return evidence; }
		}
		
#region Input
		public XPathNavigator Input {
			get { return currentInput; }
		}
		
		public XslStylesheet CurrentStylesheet {
			get { return currentStyle; }
		}

		public void PushStylesheet (XslStylesheet style)
		{
			if (currentStyle != null) styleStack.Push (currentStyle);
			currentStyle = style;
		}
		
		public void PopStylesheet ()
		{
			if (styleStack.Count == 0)
				currentStyle = null;
			else
				currentStyle = (XslStylesheet)styleStack.Pop ();
		}
		
		public void PushInputDocument (string url)
		{
			// todo: detect recursion
			Uri baseUriObj = (Input.BaseURI == String.Empty) ? null : new Uri (Input.BaseURI);
			Uri absUri = res.ResolveUri (baseUriObj, url);
			string absUriString = absUri != null ? absUri.ToString () : String.Empty;
			using (Stream s = (Stream)res.GetEntity (absUri, null, typeof(Stream)))
			{
				if (s == null)
					throw new XsltCompileException ("Can not access URI " + absUri.ToString (), null, Input);
				XmlValidatingReader vr = new XmlValidatingReader (new XmlTextReader (absUriString, s, nsMgr.NameTable));
				vr.ValidationType = ValidationType.None;
				XPathNavigator n = new XPathDocument (vr, XmlSpace.Preserve).CreateNavigator ();
				vr.Close ();
				n.MoveToFirstChild ();
				do {
					if (n.NodeType == XPathNodeType.Element)
						break;
				} while (n.MoveToNext ());
				PushInputDocument (n);
			}
		}
		
		public void PushInputDocument (XPathNavigator nav)
		{
			// Inclusion nest check
			IXmlLineInfo li = currentInput as IXmlLineInfo;
			bool hasLineInfo = (li != null && !li.HasLineInfo ());
			for (int i = 0; i < inputStack.Count; i++) {
				XPathNavigator cur = (XPathNavigator) inputStack [i];
				if (cur.BaseURI == nav.BaseURI) {
					throw new XsltCompileException (null,
						currentInput.BaseURI, 
						hasLineInfo ? li.LineNumber : 0,
						hasLineInfo ? li.LinePosition : 0);
				}
			}
			if (currentInput != null)
				inputStack.Add (currentInput);
			currentInput = nav;
		}
		
		public void PopInputDocument ()
		{
			int last = inputStack.Count - 1;
			currentInput = (XPathNavigator) inputStack [last];
			inputStack.RemoveAt (last);
		}
		
		public QName ParseQNameAttribute (string localName)
		{
			return ParseQNameAttribute (localName, String.Empty);
		}
		public QName ParseQNameAttribute (string localName, string ns)
		{
			return XslNameUtil.FromString (Input.GetAttribute (localName, ns), Input);
		}
		
		public QName [] ParseQNameListAttribute (string localName)
		{
			return ParseQNameListAttribute (localName, String.Empty);
		}
		
		public QName [] ParseQNameListAttribute (string localName, string ns)
		{
			string s = GetAttribute (localName, ns);
			if (s == null) return null;
				
			string [] names = s.Split (new char [] {' ', '\r', '\n', '\t'});
			int count=0;
			for (int i=0; i<names.Length; i++)
				if (names[i].Length != 0)
					count ++;

			QName [] ret = new QName [count];
			
			for (int i = 0, j=0; i < names.Length; i++)
				if (names[i].Length != 0)
					ret [j++] = XslNameUtil.FromString (names [i], Input);
			
			return ret;
		}
		
		public bool ParseYesNoAttribute (string localName, bool defaultVal)
		{
			return ParseYesNoAttribute (localName, String.Empty, defaultVal);
		}
		
		public bool ParseYesNoAttribute (string localName, string ns, bool defaultVal)
		{
			string s = GetAttribute (localName, ns);

			switch (s) {
			case null: return defaultVal;
			case "yes": return true;
			case "no": return false;
			default:
				throw new XsltCompileException ("Invalid value for " + localName, null, Input);
			}
		}
		
		public string GetAttribute (string localName)
		{
			return GetAttribute (localName, String.Empty);
		}
		
		public string GetAttribute (string localName, string ns)
		{
			if (!Input.MoveToAttribute (localName, ns))
				return null;
			
			string ret = Input.Value;
			Input.MoveToParent ();
			return ret;
		}
		public XslAvt ParseAvtAttribute (string localName)
		{
			return ParseAvtAttribute (localName, String.Empty);
		}
		public XslAvt ParseAvtAttribute (string localName, string ns)
		{
			return ParseAvt (GetAttribute (localName, ns));
		}
		
		public void AssertAttribute (string localName)
		{
			AssertAttribute (localName, "");
		}
		public void AssertAttribute (string localName, string ns)
		{
			if (Input.GetAttribute (localName, ns) == null)
				throw new XsltCompileException ("Was expecting the " + localName + " attribute", null, Input);
		}
		
		public XslAvt ParseAvt (string s)
		{
			if (s == null) return null;
			return new XslAvt (s, this);
		}
		
		
#endregion
#region Compile
		public Pattern CompilePattern (string pattern, XPathNavigator loc)
		{
			if (pattern == null || pattern == "") return null;
			Pattern p = Pattern.Compile (pattern, this);
			if (p == null)
				throw new XsltCompileException (String.Format ("Invalid pattern '{0}'", pattern), null, loc);
			
			return p;
		}

		internal XPathParser xpathParser;
		internal XsltPatternParser patternParser;
		internal CompiledExpression CompileExpression (string expression)
		{
			return CompileExpression (expression, false);
		}

		internal CompiledExpression CompileExpression (string expression, bool isKey)
		{
			if (expression == null || expression == "") return null;

			Expression expr = xpathParser.Compile (expression);
			if (isKey)
				expr = new ExprKeyContainer (expr);
			CompiledExpression e = new CompiledExpression (expression, expr);

			return e;
		}
		
		public XslOperation CompileTemplateContent ()
		{
			return CompileTemplateContent (XPathNodeType.All, false);
		}

		public XslOperation CompileTemplateContent (XPathNodeType parentType)
		{
			return CompileTemplateContent (parentType, false);
		}
		
		public XslOperation CompileTemplateContent (XPathNodeType parentType, bool xslForEach)
		{
			return new XslTemplateContent (this, parentType, xslForEach);
		}
#endregion
#region Variables
		public void AddGlobalVariable (XslGlobalVariable var)
		{
			globalVariables [var.Name] = var;
		}

		public void AddKey (XslKey key)
		{
			if (keys [key.Name] == null)
				keys [key.Name] = new ArrayList ();
			((ArrayList) keys [key.Name]).Add (key);
		}

		public void AddAttributeSet (XslAttributeSet set)
		{
			XslAttributeSet existing = attrSets [set.Name] as XslAttributeSet;
			// The latter set will have higher priority
			if (existing != null) {
				existing.Merge (set);
				attrSets [set.Name] = existing;
			}
			else
				attrSets [set.Name] = set;
		}
		
		VariableScope curVarScope;
		
		public void PushScope ()
		{
			curVarScope = new VariableScope (curVarScope);
		}
		
		public VariableScope PopScope ()
		{
			curVarScope.giveHighTideToParent ();
			VariableScope cur = curVarScope;
			curVarScope = curVarScope.Parent;
			return cur;
		}
		
		public int AddVariable (XslLocalVariable v)
		{
			if (curVarScope == null)
				throw new XsltCompileException ("Not initialized variable", null, Input);
			
			return curVarScope.AddVariable (v);
		}
		
		public VariableScope CurrentVariableScope { get { return curVarScope; }}
#endregion
		
#region Scope (version, {excluded, extension} namespaces)
		// FIXME: This will work, but is *very* slow
		public bool IsExtensionNamespace (string nsUri)
		{
			if (nsUri == XsltNamespace) return true;
				
			XPathNavigator nav = Input.Clone ();
			XPathNavigator nsScope = nav.Clone ();
			do {
				bool isXslt = nav.NamespaceURI == XsltNamespace;
				nsScope.MoveTo (nav);
				if (nav.MoveToFirstAttribute ()) {
					do {
						if (nav.LocalName == "extension-element-prefixes" &&
							nav.NamespaceURI == (isXslt ? String.Empty : XsltNamespace))
						{
						
							foreach (string ns in nav.Value.Split (' '))
								if (nsScope.GetNamespace (ns == "#default" ? "" : ns) == nsUri)
									return true;
						}
					} while (nav.MoveToNextAttribute ());
					nav.MoveToParent ();
				}
			} while (nav.MoveToParent ());
				
			return false;
		}
		
		public Hashtable GetNamespacesToCopy ()
		{
			Hashtable ret = new Hashtable ();
			
			XPathNavigator nav = Input.Clone ();
			XPathNavigator nsScope = nav.Clone ();
			
			if (nav.MoveToFirstNamespace (XPathNamespaceScope.ExcludeXml)) {
				do {
					if (nav.Value != XsltNamespace && !ret.Contains (nav.Name))
						ret.Add (nav.Name, nav.Value);
				} while (nav.MoveToNextNamespace (XPathNamespaceScope.ExcludeXml));
				nav.MoveToParent ();
			}
			
			do {
				bool isXslt = nav.NamespaceURI == XsltNamespace;
				nsScope.MoveTo (nav);

				if (nav.MoveToFirstAttribute ()) {
					do {
						if ((nav.LocalName == "extension-element-prefixes" || nav.LocalName == "exclude-result-prefixes") &&
							nav.NamespaceURI == (isXslt ? String.Empty : XsltNamespace))
						{
							foreach (string ns in nav.Value.Split (' ')) {
								string realNs = ns == "#default" ? "" : ns;
								
								if ((string)ret [realNs] == nsScope.GetNamespace (realNs))
									ret.Remove (realNs);
							}
						}
					} while (nav.MoveToNextAttribute ());
					nav.MoveToParent ();
				}
			} while (nav.MoveToParent ());
			
			return ret;
		}
#endregion
		
#region Decimal Format
		Hashtable decimalFormats = new Hashtable ();
		
		public void CompileDecimalFormat ()
		{
			QName nm = ParseQNameAttribute ("name");
			try {
				if (nm.Name != String.Empty)
					XmlConvert.VerifyNCName (nm.Name);
			} catch (XmlException ex) {
				throw new XsltCompileException ("Invalid qualified name", ex, Input);
			}
			XslDecimalFormat df = new XslDecimalFormat (this);
			
			if (decimalFormats.Contains (nm))
				((XslDecimalFormat)decimalFormats [nm]).CheckSameAs (df);
			else
				decimalFormats [nm] = df;
		}
#endregion
#region Static XSLT context
		Expression IStaticXsltContext.TryGetVariable (string nm)
		{
			if (curVarScope == null)
				return null;
			
			XslLocalVariable var = curVarScope.ResolveStatic (XslNameUtil.FromString (nm, Input));
			
			if (var == null)
				return null;
			
			return new XPathVariableBinding (var);
		}
		
		Expression IStaticXsltContext.TryGetFunction (QName name, FunctionArguments args)
		{
			string ns = LookupNamespace (name.Namespace);
			if (ns == XslStylesheet.MSXsltNamespace && name.Name == "node-set")
				return new MSXslNodeSet (args);
			
			if (ns != "")
				return null;

			switch (name.Name) {
				case "current": return new XsltCurrent (args);
				case "unparsed-entity-uri": return new XsltUnparsedEntityUri (args);
				case "element-available": return new XsltElementAvailable (args, this);
				case "system-property": return new XsltSystemProperty (args, this);
				case "function-available": return new XsltFunctionAvailable (args, this);
				case "generate-id": return new XsltGenerateId (args);
				case "format-number": return new XsltFormatNumber (args, this);
				case "key":
					if (KeyCompilationMode)
						throw new XsltCompileException ("Cannot use key() function inside key definition", null, this.Input);
					return new XsltKey (args, this);
				case "document": return new XsltDocument (args, this);
			}
			
			return null;
		}
		
		QName IStaticXsltContext.LookupQName (string s)
		{
			return XslNameUtil.FromString (s, Input);
		}

		public string LookupNamespace (string prefix)
		{
			if (prefix == "" || prefix == null)
				return "";
			
			XPathNavigator n = Input;
			if (Input.NodeType == XPathNodeType.Attribute) {
				n = Input.Clone ();
				n.MoveToParent ();
			}

			return n.GetNamespace (prefix);
		}
#endregion
		public void CompileOutput ()
		{
			XPathNavigator n = Input;
			string uri = n.GetAttribute ("href", "");
			XslOutput output = outputs [uri] as XslOutput;
			if (output == null) {
				output = new XslOutput (uri, stylesheetVersion);
				outputs.Add (uri, output);
			}
			output.Fill (n);
		}
	}
	
	internal class VariableScope {
		ArrayList variableNames;
		Hashtable variables;
		VariableScope parent;
		int nextSlot = 0;
		int highTide = 0; // this will be the size of the stack frame
		
		internal void giveHighTideToParent ()
		{
			if (parent != null)
				parent.highTide = System.Math.Max (VariableHighTide, parent.VariableHighTide);
		}

		public int VariableHighTide { get { return  System.Math.Max (highTide, nextSlot); }}
		
		public VariableScope (VariableScope parent)
		{
			this.parent = parent;
			if (parent != null)
				this.nextSlot = parent.nextSlot;
		}
		
		public VariableScope Parent { get { return parent; }}
		
		public int AddVariable (XslLocalVariable v)
		{
			if (variables == null) {
				variableNames = new ArrayList ();
				variables = new Hashtable ();
			}
			variables [v.Name] = v;
			int idx = variableNames.IndexOf (v.Name);
			if (idx >= 0)
				return idx;
			variableNames.Add (v.Name);
			return nextSlot++;
		}
		
		public XslLocalVariable ResolveStatic (QName name)
		{
			for (VariableScope s = this; s != null; s = s.Parent) {
				if (s.variables == null) continue;
				XslLocalVariable v = s.variables [name] as XslLocalVariable;
				if (v != null) return v;
			}
			return null;
		}
		
		public XslLocalVariable Resolve (XslTransformProcessor p, QName name)
		{
			for (VariableScope s = this; s != null; s = s.Parent) {
				if (s.variables == null) continue;
				XslLocalVariable v = s.variables [name] as XslLocalVariable;
				if (v != null && v.IsEvaluated (p))
					return v;

			}
			return null;
		}
	}
	
	internal class Sort {
		string lang;
		XmlDataType dataType;
		XmlSortOrder order;
		XmlCaseOrder caseOrder;
		
		XslAvt langAvt, dataTypeAvt, orderAvt, caseOrderAvt;
		XPathExpression expr;
			
		public Sort (Compiler c)
		{
			c.CheckExtraAttributes ("sort", "select", "lang", "data-type", "order", "case-order");
			
			expr = c.CompileExpression (c.GetAttribute ("select"));
			if (expr == null)
				expr = c.CompileExpression ("string(.)");
			
			langAvt = c.ParseAvtAttribute ("lang");
			dataTypeAvt = c.ParseAvtAttribute ("data-type");
			orderAvt = c.ParseAvtAttribute ("order");
			caseOrderAvt = c.ParseAvtAttribute ("case-order");
			
			// Precalc whatever we can
			lang = ParseLang (XslAvt.AttemptPreCalc (ref langAvt));
			dataType = ParseDataType (XslAvt.AttemptPreCalc (ref dataTypeAvt));
			order = ParseOrder (XslAvt.AttemptPreCalc (ref orderAvt));
			caseOrder = ParseCaseOrder (XslAvt.AttemptPreCalc (ref caseOrderAvt));
		}

		public bool IsContextDependent {
			get { return orderAvt != null || caseOrderAvt != null || langAvt != null || dataTypeAvt != null; }
		}

		string ParseLang (string value)
		{
			return value;
		}

		XmlDataType ParseDataType (string value)
		{
			switch (value)
			{
			case "number":
				return XmlDataType.Number;
			case "text":
			case null:
			default:
				return XmlDataType.Text;
			}
		}

		XmlSortOrder ParseOrder (string value)
		{
			switch (value)
			{
			case "descending":
				return XmlSortOrder.Descending;
			case "ascending":
			case null:
			default:
				return XmlSortOrder.Ascending;
			}	  
		}

		XmlCaseOrder ParseCaseOrder (string value)
		{
			switch (value)
			{
			case "upper-first":
				return XmlCaseOrder.UpperFirst;
			case "lower-first":
				return XmlCaseOrder.LowerFirst;
			case null:
			default:
				return XmlCaseOrder.None;
			}	  
		}
		
		
		public void AddToExpr (XPathExpression e, XslTransformProcessor p)
		{
			e.AddSort (
				expr,
				orderAvt == null ? order : ParseOrder (orderAvt.Evaluate (p)),
				caseOrderAvt == null ? caseOrder: ParseCaseOrder (caseOrderAvt.Evaluate (p)),
				langAvt == null ? lang : ParseLang (langAvt.Evaluate (p)),
				dataTypeAvt == null ? dataType : ParseDataType (dataTypeAvt.Evaluate (p))
			);
		}

		public XPathSorter ToXPathSorter (XslTransformProcessor p)
		{
			return new XPathSorter (expr, 
				orderAvt == null ? order : ParseOrder (orderAvt.Evaluate (p)),
				caseOrderAvt == null ? caseOrder: ParseCaseOrder (caseOrderAvt.Evaluate (p)),
				langAvt == null ? lang : ParseLang (langAvt.Evaluate (p)),
				dataTypeAvt == null ? dataType : ParseDataType (dataTypeAvt.Evaluate (p))
			);
		}
	}
	
	internal class XslNameUtil
	{
		public static QName [] FromListString (string names, XPathNavigator current)
		{
			string [] nameArray = names.Split (XmlChar.WhitespaceChars);
			int idx = 0;
			for (int i = 0; i < nameArray.Length; i++)
				if (nameArray [i] != String.Empty)
					idx++;

			XmlQualifiedName [] qnames = new XmlQualifiedName [idx];

			idx = 0;
			for (int i = 0; i < nameArray.Length; i++)
				if (nameArray [i] != String.Empty)
					qnames [idx++] = FromString (nameArray [i], current, true);

			return qnames;
		}

		public static QName FromString (string name, XPathNavigator current)
		{
			return FromString (name, current, false);
		}

		public static QName FromString (string name, XPathNavigator current, bool useDefaultXmlns)
		{
			if (current.NodeType == XPathNodeType.Attribute)
				(current = current.Clone ()).MoveToParent ();
			
			int colon = name.IndexOf (':');
			if (colon > 0)
				return new QName (name.Substring (colon+ 1), current.GetNamespace (name.Substring (0, colon)));
			else if (colon < 0)
				return new QName (name, useDefaultXmlns ? current.GetNamespace (String.Empty) : "");
			else
				throw new ArgumentException ("Invalid name: " + name);
		}

		public static QName FromString (string name, Hashtable nsDecls)
		{
			int colon = name.IndexOf (':');
			if (colon > 0)
				return new QName (name.Substring (colon + 1), nsDecls [name.Substring (0, colon)] as string);
			else if (colon < 0)
				return new QName (name,
					nsDecls.ContainsKey (String.Empty) ?
					(string) nsDecls [String.Empty] : String.Empty);
			else
				throw new ArgumentException ("Invalid name: " + name);
		}

		public static QName FromString (string name, IStaticXsltContext ctx)
		{
			int colon = name.IndexOf (':');
			if (colon > 0)
				return new QName (name.Substring (colon + 1), ctx.LookupNamespace (name.Substring (0, colon)));
			else if (colon < 0)
				// Default namespace is not used for unprefixed names.
				return new QName (name, "");
			else
				throw new ArgumentException ("Invalid name: " + name);
		}

		public static QName FromString (string name, XmlNamespaceManager ctx)
		{
			int colon = name.IndexOf (':');
			if (colon > 0)
				return new QName (name.Substring (colon + 1), ctx.LookupNamespace (name.Substring (0, colon), false));
			else if (colon < 0)
				// Default namespace is not used for unprefixed names.
				return new QName (name, "");
			else
				throw new ArgumentException ("Invalid name: " + name);
		}
		
		public static string LocalNameOf (string name)
		{
			int colon = name.IndexOf (':');
			if (colon > 0)
				return name.Substring (colon + 1);
			else if (colon < 0)
				return name;
			else
				throw new ArgumentException ("Invalid name: " + name);
		}
	}
}