class Minitar::PosixHeader

# File lib/minitar/posix_header.rb, line 293
def calculate_checksum(hdr)
  hdr.unpack("C*").inject(:+)
end

# File lib/minitar/posix_header.rb, line 158
def empty? = @empty

# Indicates if the header has a valid magic value.
def valid? = empty? || @magic == MAGIC_BYTES

# Returns `true` if the header is a long name special header which indicates
# that the next block of data is the filename.
def long_name? = typeflag == "L" && name == GNU_EXT_LONG_LINK

# Returns `true` if the header is a PAX extended header which contains
# metadata for the next file entry.
def pax_header? = typeflag == "x"

# Sets the `name` to the `value` provided and clears `prefix`.
#
# Used by Minitar::Reader#each_entry to set the long name when processing GNU long
# filename extensions.
#
# The `value` must be the complete name, including leading directory components.
def long_name=(value)
  valid_name!(value)

  @prefix = ""
  @name = value
end

# A string representation of the header.
def to_s
  update_checksum
  header(@checksum)
end
alias_method :to_str, :to_s

# TODO: In Minitar 2, PosixHeader#to_str will be removed.

# Update the checksum field.
def update_checksum
  hh = header(" " * 8)
  @checksum = oct(calculate_checksum(hh), 6)
end
##
# :attr_accessor: name
# The name of the file. Required.
#
# By default, limited to 100 bytes, but may be up to BLOCK_SIZE bytes if using the
# GNU long name tar extension.

##
# :attr_accessor: size
# The size of the file. Required.

##
# :attr_reader: prefix
# The prefix of the file; the path before #name. Limited to 155 bytes.
# Required.

##
# :attr_reader: mode
# The Unix file mode of the file. Stored as an octal integer. Required.

##
# :attr_reader: uid
# The Unix owner user ID of the file. Stored as an octal integer.

##
# :attr_reader: uname
# The user name of the Unix owner of the file.

##
# :attr_reader: gid
# The Unix owner group ID of the file. Stored as an octal integer.

##
# :attr_reader: gname
# The group name of the Unix owner of the file.

##
# :attr_reader: mtime
# The modification time of the file in epoch seconds. Stored as an
# octal integer.

##
# :attr_reader: checksum
# The checksum of the file. Stored as an octal integer. Calculated
# before encoding the header as a string.

##
# :attr_reader: typeflag
# The type of record in the file.
#
# - `0`: Regular file. NULL should be treated as a synonym, for compatibility purposes.
# - `1`: Hard link.
# - `2`: Symbolic link.
# - `3`: Character device node.
# - `4`: Block device node.
# - `5`: Directory.
# - `6`: FIFO node.
# - `7`: Reserved.
# - `L`: GNU extension for long filenames when #name is `././@LongLink`.

##
# :attr_reader: linkname
# The target of the symbolic link.

##
# :attr_reader: magic
# Always "ustar\0".

##
# :attr_reader: version
# Always "00"

##
# :attr_reader: devmajor
# The major device ID. Not currently used.

##
# :attr_reader: devminor
# The minor device ID. Not currently used.

private

def valid_name!(value)
  return if value.is_a?(String) && !value.empty?
  raise ArgumentError, "Field name must be a non-empty string"
end

def oct(num, len)
  if num.nil?
    "\0" * (len + 1)
  else
    "%0#{len}o" % num
  end
end

def calculate_checksum(hdr)
  hdr.unpack("C*").inject(:+)
end

def header(chksum)
  arr = [name, oct(mode, 7), oct(uid, 7), oct(gid, 7), oct(size, 11),
    oct(mtime, 11), chksum, " ", typeflag, linkname, magic, version,
    uname, gname, oct(devmajor, 7), oct(devminor, 7), prefix]
  str = arr.pack(HEADER_PACK_FORMAT)
  str + "\0" * ((BLOCK_SIZE - str.bytesize) % BLOCK_SIZE

# File lib/minitar/posix_header.rb, line 69
def from_data(data)
  fields = data.unpack(HEADER_UNPACK_FORMAT)
  name = fields.shift
  mode = fields.shift.oct
  uid = fields.shift.oct
  gid = fields.shift.oct
  size = parse_numeric_field(fields.shift)
  mtime = fields.shift.oct
  checksum = fields.shift.oct
  typeflag = fields.shift
  linkname = fields.shift
  magic = fields.shift
  version = fields.shift.oct
  uname = fields.shift
  gname = fields.shift
  devmajor = fields.shift.oct
  devminor = fields.shift.oct
  prefix = fields.shift

  empty = !data.each_byte.any?(&:nonzero?)

  new(
    name: name,
    mode: mode,
    uid: uid,
    gid: gid,
    size: size,
    mtime: mtime,
    checksum: checksum,
    typeflag: typeflag,
    magic: magic,
    version: version,
    uname: uname,
    gname: gname,
    devmajor: devmajor,
    devminor: devminor,
    prefix: prefix,
    empty: empty,
    linkname: linkname
  )
end

# File lib/minitar/posix_header.rb, line 66
  def from_stream(stream) = from_data(stream.read(BLOCK_SIZE))

  # Creates a new PosixHeader from a BLOCK_SIZE-byte data buffer.
  def from_data(data)
    fields = data.unpack(HEADER_UNPACK_FORMAT)
    name = fields.shift
    mode = fields.shift.oct
    uid = fields.shift.oct
    gid = fields.shift.oct
    size = parse_numeric_field(fields.shift)
    mtime = fields.shift.oct
    checksum = fields.shift.oct
    typeflag = fields.shift
    linkname = fields.shift
    magic = fields.shift
    version = fields.shift.oct
    uname = fields.shift
    gname = fields.shift
    devmajor = fields.shift.oct
    devminor = fields.shift.oct
    prefix = fields.shift

    empty = !data.each_byte.any?(&:nonzero?)

    new(
      name: name,
      mode: mode,
      uid: uid,
      gid: gid,
      size: size,
      mtime: mtime,
      checksum: checksum,
      typeflag: typeflag,
      magic: magic,
      version: version,
      uname: uname,
      gname: gname,
      devmajor: devmajor,
      devminor: devminor,
      prefix: prefix,
      empty: empty,
      linkname: linkname
    )
  end

  private

  def parse_numeric_field(string)
    return string.oct if /\A[0-7 \0]*\z/.match?(string) # \0 appears as a padding
    return parse_base256(string) if string.bytes.first == 0x80 || string.bytes.first == 0xff
    raise ArgumentError, "#{string.inspect} is not a valid numeric field"
  end

  def parse_base256(string)
    # https://www.gnu.org/software/tar/manual/html_node/Extensions.html
    bytes = string.bytes
    case bytes.first
    when 0x80 # Positive number: *non-leading* bytes, number in big-endian order
      bytes[1..].inject(0) { |r, byte| (r << 8) | byte }
    when 0xff # Negative number: *all* bytes, two's complement in big-endian order
      result = bytes.inject(0) { |r, byte| (r << 8) | byte }
      bit_length = bytes.size * 8
      result - (1 << bit_length)
    else
      raise ArgumentError, "Invalid binary field format"
    end
  end
end

# File lib/minitar/posix_header.rb, line 297
def header(chksum)
  arr = [name, oct(mode, 7), oct(uid, 7), oct(gid, 7), oct(size, 11),
    oct(mtime, 11), chksum, " ", typeflag, linkname, magic, version,
    uname, gname, oct(devmajor, 7), oct(devminor, 7), prefix]
  str = arr.pack(HEADER_PACK_FORMAT)
  str + "\0" * ((BLOCK_SIZE - str.bytesize) % BLOCK_SIZE)
end

# File lib/minitar/posix_header.rb, line 137
def initialize(v)
  REQUIRED_FIELDS.each do |f|
    raise ArgumentError, "Field #{f} is required." unless v.key?(f)
  end

  v[:mtime] = v[:mtime].to_i
  v[:checksum] ||= ""
  v[:typeflag] ||= "0"
  v[:magic] ||= MAGIC_BYTES
  v[:version] ||= "00"

  FIELDS.each do |f|
    instance_variable_set(:"@#{f}", v[f])
  end

  @empty = v[:empty]

  valid_name!(v[:name]) unless v[:empty]
end

# File lib/minitar/posix_header.rb, line 177
def long_name=(value)
  valid_name!(value)

  @prefix = ""
  @name = value
end

# File lib/minitar/posix_header.rb, line 165
def long_name? = typeflag == "L" && name == GNU_EXT_LONG_LINK

# Returns `true` if the header is a PAX extended header which contains
# metadata for the next file entry.
def pax_header? = typeflag == "x"

# Sets the `name` to the `value` provided and clears `prefix`.
#
# Used by Minitar::Reader#each_entry to set the long name when processing GNU long
# filename extensions.
#
# The `value` must be the complete name, including leading directory components.
def long_name=(value)
  valid_name!(value)

  @prefix = ""
  @name = value
end

# A string representation of the header.
def to_s
  update_checksum
  header(@checksum)
end
alias_method :to_str, :to_s

# TODO: In Minitar 2, PosixHeader#to_str will be removed.

# Update the checksum field.
def update_checksum
  hh = header(" " * 8)
  @checksum = oct(calculate_checksum(hh), 6)
end
##
# :attr_accessor: name
# The name of the file. Required.
#
# By default, limited to 100 bytes, but may be up to BLOCK_SIZE bytes if using the
# GNU long name tar extension.

##
# :attr_accessor: size
# The size of the file. Required.

##
# :attr_reader: prefix
# The prefix of the file; the path before #name. Limited to 155 bytes.
# Required.

##
# :attr_reader: mode
# The Unix file mode of the file. Stored as an octal integer. Required.

##
# :attr_reader: uid
# The Unix owner user ID of the file. Stored as an octal integer.

##
# :attr_reader: uname
# The user name of the Unix owner of the file.

##
# :attr_reader: gid
# The Unix owner group ID of the file. Stored as an octal integer.

##
# :attr_reader: gname
# The group name of the Unix owner of the file.

##
# :attr_reader: mtime
# The modification time of the file in epoch seconds. Stored as an
# octal integer.

##
# :attr_reader: checksum
# The checksum of the file. Stored as an octal integer. Calculated
# before encoding the header as a string.

##
# :attr_reader: typeflag
# The type of record in the file.
#
# - `0`: Regular file. NULL should be treated as a synonym, for compatibility purposes.
# - `1`: Hard link.
# - `2`: Symbolic link.
# - `3`: Character device node.
# - `4`: Block device node.
# - `5`: Directory.
# - `6`: FIFO node.
# - `7`: Reserved.
# - `L`: GNU extension for long filenames when #name is `././@LongLink`.

##
# :attr_reader: linkname
# The target of the symbolic link.

##
# :attr_reader: magic
# Always "ustar\0".

##
# :attr_reader: version
# Always "00"

##
# :attr_reader: devmajor
# The major device ID. Not currently used.

##
# :attr_reader: devminor
# The minor device ID. Not currently used.

private

def valid_name!(value)
  return if value.is_a?(String) && !value.empty?
  raise ArgumentError, "Field name must be a non-empty string"
end

def oct(num, len)
  if num.nil?
    "\0" * (len + 1)
  else
    "%0#{len}o" % num
  end
end

def calculate_checksum(hdr)
  hdr.unpack("C*").inject(:+)
end

def header(chksum)
  arr = [name, oct(mode, 7), oct(uid, 7), oct(gid, 7), oct(size, 11),
    oct(mtime, 11), chksum, " ", typeflag, linkname, magic, version,
    uname, gname, oct(devmajor, 7), oct(devminor, 7), prefix]
  str = arr.pack(HEADER_PACK_FORMAT)
  str + "\0" * ((BLOCK_SIZE - str.bytesize) % BLOCK_SIZE)
end

# File lib/minitar/posix_header.rb, line 285
def oct(num, len)
  if num.nil?
    "\0" * (len + 1)
  else
    "%0#{len}o" % num
  end
end

# File lib/minitar/posix_header.rb, line 119
def parse_base256(string)
  # https://www.gnu.org/software/tar/manual/html_node/Extensions.html
  bytes = string.bytes
  case bytes.first
  when 0x80 # Positive number: *non-leading* bytes, number in big-endian order
    bytes[1..].inject(0) { |r, byte| (r << 8) | byte }
  when 0xff # Negative number: *all* bytes, two's complement in big-endian order
    result = bytes.inject(0) { |r, byte| (r << 8) | byte }
    bit_length = bytes.size * 8
    result - (1 << bit_length)
  else
    raise ArgumentError, "Invalid binary field format"
  end
end

# File lib/minitar/posix_header.rb, line 113
def parse_numeric_field(string)
  return string.oct if /\A[0-7 \0]*\z/.match?(string) # \0 appears as a padding
  return parse_base256(string) if string.bytes.first == 0x80 || string.bytes.first == 0xff
  raise ArgumentError, "#{string.inspect} is not a valid numeric field"
end

# File lib/minitar/posix_header.rb, line 169
  def pax_header? = typeflag == "x"

  # Sets the `name` to the `value` provided and clears `prefix`.
  #
  # Used by Minitar::Reader#each_entry to set the long name when processing GNU long
  # filename extensions.
  #
  # The `value` must be the complete name, including leading directory components.
  def long_name=(value)
    valid_name!(value)

    @prefix = ""
    @name = value
  end

  # A string representation of the header.
  def to_s
    update_checksum
    header(@checksum)
  end
  alias_method :to_str, :to_s

  # TODO: In Minitar 2, PosixHeader#to_str will be removed.

  # Update the checksum field.
  def update_checksum
    hh = header(" " * 8)
    @checksum = oct(calculate_checksum(hh), 6)
  end
  ##
  # :attr_accessor: name
  # The name of the file. Required.
  #
  # By default, limited to 100 bytes, but may be up to BLOCK_SIZE bytes if using the
  # GNU long name tar extension.

  ##
  # :attr_accessor: size
  # The size of the file. Required.

  ##
  # :attr_reader: prefix
  # The prefix of the file; the path before #name. Limited to 155 bytes.
  # Required.

  ##
  # :attr_reader: mode
  # The Unix file mode of the file. Stored as an octal integer. Required.

  ##
  # :attr_reader: uid
  # The Unix owner user ID of the file. Stored as an octal integer.

  ##
  # :attr_reader: uname
  # The user name of the Unix owner of the file.

  ##
  # :attr_reader: gid
  # The Unix owner group ID of the file. Stored as an octal integer.

  ##
  # :attr_reader: gname
  # The group name of the Unix owner of the file.

  ##
  # :attr_reader: mtime
  # The modification time of the file in epoch seconds. Stored as an
  # octal integer.

  ##
  # :attr_reader: checksum
  # The checksum of the file. Stored as an octal integer. Calculated
  # before encoding the header as a string.

  ##
  # :attr_reader: typeflag
  # The type of record in the file.
  #
  # - `0`: Regular file. NULL should be treated as a synonym, for compatibility purposes.
  # - `1`: Hard link.
  # - `2`: Symbolic link.
  # - `3`: Character device node.
  # - `4`: Block device node.
  # - `5`: Directory.
  # - `6`: FIFO node.
  # - `7`: Reserved.
  # - `L`: GNU extension for long filenames when #name is `././@LongLink`.

  ##
  # :attr_reader: linkname
  # The target of the symbolic link.

  ##
  # :attr_reader: magic
  # Always "ustar\0".

  ##
  # :attr_reader: version
  # Always "00"

  ##
  # :attr_reader: devmajor
  # The major device ID. Not currently used.

  ##
  # :attr_reader: devminor
  # The minor device ID. Not currently used.

  private

  def valid_name!(value)
    return if value.is_a?(String) && !value.empty?
    raise ArgumentError, "Field name must be a non-empty string"
  end

  def oct(num, len)
    if num.nil?
      "\0" * (len + 1)
    else
      "%0#{len}o" % num
    end
  end

  def calculate_checksum(hdr)
    hdr.unpack("C*").inject(:+)
  end

  def header(chksum)
    arr = [name, oct(mode, 7), oct(uid, 7), oct(gid, 7), oct(size, 11),
      oct(mtime, 11), chksum, " ", typeflag, linkname, magic, version,
      uname, gname, oct(devmajor, 7), oct(devminor, 7), prefix]
    str = arr.pack(HEADER_PACK_FORMAT)
    str + "\0" * ((BLOCK_SIZE - str.bytesize) % BLOCK_SIZE)
  end
end

# File lib/minitar/posix_header.rb, line 185
def to_s
  update_checksum
  header(@checksum)
end

# File lib/minitar/posix_header.rb, line 194
def update_checksum
  hh = header(" " * 8)
  @checksum = oct(calculate_checksum(hh), 6)
end

# File lib/minitar/posix_header.rb, line 161
def valid? = empty? || @magic == MAGIC_BYTES

# Returns `true` if the header is a long name special header which indicates
# that the next block of data is the filename.
def long_name? = typeflag == "L" && name == GNU_EXT_LONG_LINK

# Returns `true` if the header is a PAX extended header which contains
# metadata for the next file entry.
def pax_header? = typeflag == "x"

# Sets the `name` to the `value` provided and clears `prefix`.
#
# Used by Minitar::Reader#each_entry to set the long name when processing GNU long
# filename extensions.
#
# The `value` must be the complete name, including leading directory components.
def long_name=(value)
  valid_name!(value)

  @prefix = ""
  @name = value
end

# A string representation of the header.
def to_s
  update_checksum
  header(@checksum)
end
alias_method :to_str, :to_s

# TODO: In Minitar 2, PosixHeader#to_str will be removed.

# Update the checksum field.
def update_checksum
  hh = header(" " * 8)
  @checksum = oct(calculate_checksum(hh), 6)
end
##
# :attr_accessor: name
# The name of the file. Required.
#
# By default, limited to 100 bytes, but may be up to BLOCK_SIZE bytes if using the
# GNU long name tar extension.

##
# :attr_accessor: size
# The size of the file. Required.

##
# :attr_reader: prefix
# The prefix of the file; the path before #name. Limited to 155 bytes.
# Required.

##
# :attr_reader: mode
# The Unix file mode of the file. Stored as an octal integer. Required.

##
# :attr_reader: uid
# The Unix owner user ID of the file. Stored as an octal integer.

##
# :attr_reader: uname
# The user name of the Unix owner of the file.

##
# :attr_reader: gid
# The Unix owner group ID of the file. Stored as an octal integer.

##
# :attr_reader: gname
# The group name of the Unix owner of the file.

##
# :attr_reader: mtime
# The modification time of the file in epoch seconds. Stored as an
# octal integer.

##
# :attr_reader: checksum
# The checksum of the file. Stored as an octal integer. Calculated
# before encoding the header as a string.

##
# :attr_reader: typeflag
# The type of record in the file.
#
# - `0`: Regular file. NULL should be treated as a synonym, for compatibility purposes.
# - `1`: Hard link.
# - `2`: Symbolic link.
# - `3`: Character device node.
# - `4`: Block device node.
# - `5`: Directory.
# - `6`: FIFO node.
# - `7`: Reserved.
# - `L`: GNU extension for long filenames when #name is `././@LongLink`.

##
# :attr_reader: linkname
# The target of the symbolic link.

##
# :attr_reader: magic
# Always "ustar\0".

##
# :attr_reader: version
# Always "00"

##
# :attr_reader: devmajor
# The major device ID. Not currently used.

##
# :attr_reader: devminor
# The minor device ID. Not currently used.

private

def valid_name!(value)
  return if value.is_a?(String) && !value.empty?
  raise ArgumentError, "Field name must be a non-empty string"
end

def oct(num, len)
  if num.nil?
    "\0" * (len + 1)
  else
    "%0#{len}o" % num
  end
end

def calculate_checksum(hdr)
  hdr.unpack("C*").inject(:+)
end

def header(chksum)
  arr = [name, oct(mode, 7), oct(uid, 7), oct(gid, 7), oct(size, 11),
    oct(mtime, 11), chksum, " ", typeflag, linkname, magic, version,
    uname, gname, oct(devmajor, 7), oct(devminor, 7), prefix]
  str = arr.pack(HEADER_PACK_FORMAT)
  str + "\0" * ((BLOCK_SIZE - str.bytesize) % BLOCK_SIZE)

# File lib/minitar/posix_header.rb, line 280
def valid_name!(value)
  return if value.is_a?(String) && !value.empty?
  raise ArgumentError, "Field name must be a non-empty string"
end

# File lib/minitar/posix_header.rb, line 52
def name=(value)
  valid_name!(value)
  @name = value
end