class_docstr: Support for `Visual Chart <www.visualchart.com>`_ binary on-disk files for
  both daily and intradaily formats.
  
  Note:
  
    - ``dataname``: to file or open file-like object
  
      If a file-like object is passed, the ``timeframe`` parameter will be
      used to determine which is the actual timeframe.
  
      Else the file extension (``.fd`` for daily and ``.min`` for intraday)
      will be used.
class_docstr_tok: ["Support","for","`","Visual","Chart","<","www.visualchart.com",">","`","_","binary","on-disk","files","for","both","daily","and","intradaily","formats",".","Note",":","-","``","dataname","``",":","to","file","or","open","file-like","object","If","a","file-like","object","is","passed",",","the","``","timeframe","``","parameter","will","be","used","to","determine","which","is","the","actual","timeframe",".","Else","the","file","extension","(","``",".fd","``","for","daily","and","``",".min","``","for","intraday",")","will","be","used","."]
code: def _load(self):
      if self.f is None:
          return False
  
      # Let an exception propagate to let the caller know
      bardata = self.f.read(self.barsize)
      if not bardata:
          return False
  
      bdata = struct.unpack(self.barfmt, bardata)
  
      # Years are stored as if they had 500 days
      y, md = divmod(bdata[0], 500)
      # Months are stored as if they had 32 days
      m, d = divmod(md, 32)
      dt = datetime.datetime(y, m, d)
  
      if self.dtsize > 1:  # Minute Bars
          # Daily Time is stored in seconds
          hhmm, ss = divmod(bdata[1], 60)
          hh, mm = divmod(hhmm, 60)
          dt = dt.replace(hour=hh, minute=mm, second=ss)
  
      self.lines.datetime[0] = date2num(dt)
  
      o, h, l, c, v, oi = bdata[self.dtsize :]
      self.lines.open[0] = o
      self.lines.high[0] = h
      self.lines.low[0] = l
      self.lines.close[0] = c
      self.lines.volume[0] = v
      self.lines.openinterest[0] = oi
  
      return True
  
file_path: backtrader/backtrader/feeds/vchart.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import datetime
  import struct
  import os.path
  from ..None import feed
  from ..None import TimeFrame
  from ..utils import date2num
label_desc: Use image node_id 3 for calling the VChartData obj's underlying member method code with example usage: obj._load() and returns: True, False, False