@spec preamble() :: binary()

Generates a P10 preamble (128 zero bytes + "DICM").

@spec sanitize_preamble(binary()) :: {:ok, binary()} | {:error, :invalid_preamble}

Sanitizes the preamble by zeroing it out.

Per PS3.10 Section 7.5, the preamble can contain malicious content. This function replaces the 128-byte preamble with zeros while preserving the DICM prefix and all subsequent data.

@spec skip_preamble(binary()) :: {:ok, binary()} | {:error, :invalid_preamble}

Validates and skips the 128-byte preamble and "DICM" magic.

Returns the remaining binary after the preamble, or an error.

@spec validate_preamble(binary()) ::
  :ok | {:warning, :non_standard_preamble} | {:error, :invalid_preamble}

Validates the preamble content per PS3.10 Section 7.5.

Returns:

• :ok if preamble is all zeros or starts with recognized dual-format magic (TIFF)
• {:warning, :non_standard_preamble} if preamble contains non-standard content
• {:error, :invalid_preamble} if the binary is not a valid DICOM file