pydicom.fileutil.read_undefined_length_value(fp: BinaryIO, is_little_endian: bool, delimiter_tag: BaseTag, defer_size: int | float | None = None, read_size: int = 8192) bytes | None[source]

Read until delimiter_tag and return the value up to that point.

On completion, the file will be set to the first byte after the delimiter and its following four zero bytes.

  • fp (file-like) – The file-like to read.

  • is_little_endian (bool) – True if file transfer syntax is little endian, else False.

  • delimiter_tag (BaseTag) – Tag used as end marker for reading

  • defer_size (int or None, optional) – Size to avoid loading large elements in memory. See dcmread() for more parameter info.

  • read_size (int, optional) – Number of bytes to read at one time.


delimiter – The file delimiter.

Return type:

bytes or None


EOFError – If EOF is reached before delimiter found.