code: def _read_segments_c(raw, data, idx, fi, start, stop, cals, mult):
      """Read chunk of vectorized raw data."""
      n_samples = raw._raw_extras[fi]["n_samples"]
      fmt = raw._raw_extras[fi]["fmt"]
      dtype = _fmt_dtype_dict[fmt]
      n_bytes = _fmt_byte_dict[fmt]
      n_channels = raw._raw_extras[fi]["orig_nchan"]
      block = np.zeros((n_channels, stop - start))
      with open(raw._filenames[fi], "rb", buffering=0) as fid:
          ids = (
              np.arange(idx.start, idx.stop)
              if isinstance(idx, slice)
              else idx
          )
          for ch_id in ids:
              fid.seek(start * n_bytes + ch_id * n_bytes * n_samples)
              block[ch_id] = np.fromfile(fid, dtype, stop - start)
      _mult_cal_one(data, block, idx, cals, mult)
  
imports: import configparser
  import os
  import os.path
  import re
  from datetime import datetime, timezone
  from io import StringIO
  import numpy
  from ..._fiff.constants import FIFF
  from ..._fiff.meas_info import _empty_info
  from ..._fiff.utils import _mult_cal_one, _read_segments_file
  from ...annotations import Annotations, read_annotations
  from ...channels import make_dig_montage
  from ...defaults import HEAD_SIZE_DEFAULT
  from ...transforms import _sph_to_cart
  from ...utils import _DefaultEventParser, fill_doc, logger, verbose, warn
  from ..base import BaseRaw
label_desc: Use image node_id 1 for calling a global function with example usage: _read_segments_c(raw, data, idx, fi, start, stop, cals, mult) without return types