text: """Contains data helper functions."""
  from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  
  import json
  import codecs
  import os
  import tarfile
  import time
  from Queue import Queue
  from threading import Thread
  from multiprocessing import Process, Manager, Value
  from paddle.dataset.common import md5file
  
  
  def read_manifest(manifest_path, max_duration=float('inf'), min_duration=0.0):
      """Load and parse manifest file.
  
      Instances with durations outside [min_duration, max_duration] will be
      filtered out.
  
      :param manifest_path: Manifest file to load and parse.
      :type manifest_path: basestring
      :param max_duration: Maximal duration in seconds for instance filter.
      :type max_duration: float
      :param min_duration: Minimal duration in seconds for instance filter.
      :type min_duration: float
      :return: Manifest parsing results. List of dict.
      :rtype: list
      :raises IOError: If failed to parse the manifest.
      """
      manifest = []
      for json_line in codecs.open(manifest_path, 'r', 'utf-8'):
          try:
              json_data = json.loads(json_line)
          except Exception as e:
              raise IOError("Error reading manifest: %s" % str(e))
          if (json_data["duration"] <= max_duration and
                  json_data["duration"] >= min_duration):
              manifest.append(json_data)
      return manifest
  
  
  def getfile_insensitive(path):
      """Get the actual file path when given insensitive filename."""
      directory, filename = os.path.split(path)
      directory, filename = (directory or '.'), filename.lower()
      for f in os.listdir(directory):
          newpath = os.path.join(directory, f)
          if os.path.isfile(newpath) and f.lower() == filename:
              return newpath
  
  
  def download_multi(url, target_dir, extra_args):
      """Download multiple files from url to target_dir."""
      if not os.path.exists(target_dir): os.makedirs(target_dir)
      print("Downloading %s ..." % url)
      ret_code = os.system("wget -c " + url + ' ' + extra_args + " -P " +
                           target_dir)
      return ret_code
  
  
  def download(url, md5sum, target_dir):
      """Download file from url to target_dir, and check md5sum."""
      if not os.path.exists(os.path.join(target_dir[0], target_dir[1])): os.makedirs(os.path.join(target_dir[0], target_dir[1]))
      filepath = os.path.join(target_dir[0], url.split("/")[-1])
      if not (os.path.exists(filepath) and md5file(filepath) == md5sum):
          print("Downloading %s ..." % url)
          os.system("wget -c " + url + " -P " + target_dir)
          print("\nMD5 Chesksum %s ..." % filepath)
          if not md5file(filepath) == md5sum:
              raise RuntimeError("MD5 checksum failed.")
      else:
          print("File exists, skip downloading. (%s)" % filepath)
      return filepath
  
  
  def unpack(filepath, target_dir, rm_tar=False):
      """Unpack the file to the target_dir."""
      print("Unpacking %s ..." % filepath)
      tar = tarfile.open(filepath)
      tar.extractall(target_dir)
      tar.close()
      # if rm_tar == True:
      #     os.remove(filepath)
  
  
  class XmapEndSignal():
      pass
  