getwinddata: easy to get wind data using WindR

#
#   extraTechInds: extra Technical Indicators of TTR and quantmod
#
#   Copyright (C) 2016  Chen Chaozong
#
#   This program 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 of the License, or
#   (at your option) any later version.
#
#   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
#

#' Retrieve Wind snapshot data
#'
#' @aliases getwss
#' @param windcodes wind codes in w.wss
#' @param windfields fields in w.wss
#' @param options options in w.wss, use w.menu to get more help
#' @export

getwss <- function(windcodes,windfields, options = ""){
  if(checkwindr()!=0) return(NULL)
  tmpdata <- w.wss(windcodes,windfields,options)
  if(!tmpdata$ErrorCode==0) {
    message(paste("Can not get wind data, error code:",tmpdata$ErrorCode))
    return(NULL)
  }
  out <- tmpdata$Data
  names(out) <- tolower(names(out))
  return(out)
}