Method SkipNBytes

tensorflow/core/lib/io/random_inputstream.cc:70–101

static constexpr int64 kMaxSkipSize = 8 * 1024 * 1024;

Status RandomAccessInputStream::SkipNBytes(int64 bytes_to_skip) {
  if (bytes_to_skip < 0) {
    return errors::InvalidArgument("Can't skip a negative number of bytes");
  }
  std::unique_ptr<char[]> scratch(new char[kMaxSkipSize]);
  // Try to read 1 bytes first, if we could complete the read then EOF is
  // not reached yet and we could return.
  if (bytes_to_skip > 0) {
    StringPiece data;
    Status s = file_->Read(pos_ + bytes_to_skip - 1, 1, &data, scratch.get());
    if ((s.ok() || errors::IsOutOfRange(s)) && data.size() == 1) {
      pos_ += bytes_to_skip;
      return Status::OK();
    }
  }
  // Read kDefaultSkipSize at a time till bytes_to_skip.
  while (bytes_to_skip > 0) {
    int64 bytes_to_read = std::min<int64>(kMaxSkipSize, bytes_to_skip);
    StringPiece data;
    Status s = file_->Read(pos_, bytes_to_read, &data, scratch.get());
    if (s.ok() || errors::IsOutOfRange(s)) {
      pos_ += data.size();
    } else {
      return s;
    }
    if (data.size() < bytes_to_read) {
      return errors::OutOfRange("reached end of file");
    }
    bytes_to_skip -= bytes_to_read;
  }
  return Status::OK();
}

int64 RandomAccessInputStream::Tell() const { return pos_; }