Fixed kaitai struct for zx spectrum .tap files (fixed prefixing data with header)

tap.ksy

meta:
  id: zx_spectrum_tap
  file-extension: tap
  endian: le
  license: CC0-1.0
  title: ZX Spectrum tape file format
  xref:
    justsolve: TAP_(ZX_Spectrum)
    pronom: fmt/801
doc-ref: https://faqwiki.zxnet.co.uk/wiki/TAP_format
seq:
  - id: block
    type: block
    repeat: eos
enums:
  flag_enum:
    0x00: header
    0xFF: data
  header_type_enum:
    0: program
    1: num_array
    2: char_array
    3: bytes
types:
  block:
    seq:
      - id: len_block
        type: u2
      - id: flag
        type: u1
        enum: flag_enum
      - id: header
        type: header
        if: len_block == 0x13 and flag == flag_enum::header
      - id: data
        if: len_block != 0x13 or flag != flag_enum::header
        size: len_block - 2
      - id: checksum
        type: u1
        doc: Bitwise XOR of all bytes including the flag byte
  header:
    seq:
      - id: header_type
        type: u1
        enum: header_type_enum
      - id: filename
        size: 10
        pad-right: 0x20
      - id: len_data
        type: u2
      - id: params
        type:
          switch-on: header_type
          cases:
            'header_type_enum::program': program_params
            'header_type_enum::num_arry': array_params
            'header_type_enum::char_arry': array_params
            'header_type_enum::bytes': bytes_params
  program_params:
    seq:
      - id: autostart_line
        type: u2
      - id: len_program
        type: u2
  array_params:
    seq:
      - id: reserved
        type: u1
      - id: var_name
        type: u1
        doc: Variable name (1..26 meaning A$..Z$ +192)
      - id: reserved1
        contents: [0x00, 0x80]
  bytes_params:
    seq:
      - id: start_address
        type: u2
      - id: reserved
        size: 2