/*
 * call-seq:
 *  parse_memory(data)
 *
 * Parse the XML stored in memory in +data+
 */
static VALUE parse_memory(VALUE klass, VALUE data)
{
  xmlParserCtxtPtr ctxt;

  if(NIL_P(data)) rb_raise(rb_eArgError, "data cannot be nil");
  if(!(int)RSTRING_LEN(data))
    rb_raise(rb_eRuntimeError, "data cannot be empty");

  ctxt = xmlCreateMemoryParserCtxt(
      StringValuePtr(data),
      (int)RSTRING_LEN(data)
  );

  return Data_Wrap_Struct(klass, NULL, deallocate, ctxt);
}