/// <summary>
/// Extend the XPath2 FunctionTable with 'base64decode' function to decode a base64 string to a string.
/// </summary>
/// <param name="functionTable">The function table.</param>
public static void AddBase64Decode(this FunctionTable functionTable)
{
string Base64DecodeDelegate(XPath2Context context, IContextProvider provider, object[] args)
{
bool fixPadding = true;
Encoding encoding = Encoding.UTF8;
string value = CoreFuncs.CastToStringExactOne(context, args[0]);
if (args.Length == 2)
{
try
{
// first try to cast to bool
fixPadding = CoreFuncs.GetBooleanValue(args[1]);
}
catch (Exception)
{
// else parse as encoding
encoding = ParseEncodingFromArg(context, args[1]);
}
}
if (args.Length == 3)
{
encoding = ParseEncodingFromArg(context, args[1]);
fixPadding = CoreFuncs.GetBooleanValue(args[2]);
}
if (fixPadding)
{
value = value.Trim('=');
int mod = value.Length % 4;
if (mod != 0)
{
value = string.Concat(value, new string('=', 4 - mod));
}
}
try
{
return(encoding.GetString(Convert.FromBase64String(value)));
}
catch (Exception ex)
{
throw new XPath2Exception("InvalidFormat", ex.Message);
}
}
// base64decode with default UTF-8 encoding
functionTable.Add(XmlReservedNs.NsXQueryFunc, "base64decode", 1, XPath2ResultType.String, Base64DecodeDelegate);
// base64decode with specified encoding (string) or fixPadding (bool)
functionTable.Add(XmlReservedNs.NsXQueryFunc, "base64decode", 2, XPath2ResultType.String, Base64DecodeDelegate);
// base64decode with specified encoding (string) and fixPadding (bool)
functionTable.Add(XmlReservedNs.NsXQueryFunc, "base64decode", 3, XPath2ResultType.String, Base64DecodeDelegate);
}
private IEnumerable <XPathItem> CreateEnumerator(object[] dataPool, AbstractNode expr,
XPath2NodeIterator baseIter)
{
XPath2NodeIterator iter = baseIter.Clone();
ValueNode numexpr = expr as ValueNode;
if (numexpr != null && numexpr.Content is Integer)
{
Integer pos = (Integer)numexpr.Content;
foreach (XPathItem item in iter)
{
if (pos == 1)
{
yield return(item);
break;
}
else
{
pos--;
}
}
}
else
{
ContextProvider provider = new ContextProvider(iter);
object res = Undefined.Value;
while (iter.MoveNext())
{
if (m_contextSensitive || res == Undefined.Value)
{
res = expr.Execute(provider, dataPool);
}
if (res == Undefined.Value)
{
if (!m_contextSensitive)
{
break;
}
continue;
}
XPath2NodeIterator iter2 = res as XPath2NodeIterator;
XPathItem item;
if (iter2 != null)
{
iter2 = iter2.Clone();
if (!iter2.MoveNext())
{
continue;
}
item = iter2.Current.Clone();
if (!item.IsNode && iter2.MoveNext())
{
throw new XPath2Exception("FORG0006", Resources.FORG0006, "fn:boolean()",
new SequenceType(XmlTypeCode.AnyAtomicType, XmlTypeCardinality.OneOrMore));
}
}
else
{
item = res as XPathItem;
if (item == null)
{
item = new XPath2Item(res);
}
}
if (item.IsNode)
{
yield return(iter.Current);
}
else
{
if (ValueProxy.IsNumeric(item.ValueType))
{
if (CoreFuncs.OperatorEq(iter.CurrentPosition + 1, item.GetTypedValue()) == CoreFuncs.True)
{
yield return(iter.Current);
if (!m_contextSensitive)
{
break;
}
}
}
else if (CoreFuncs.GetBooleanValue(item))
{
yield return(iter.Current);
}
}
}
}
}
