Module: MiniTarball::HeaderFormatter

Defined in:
lib/mini_tarball/header_formatter.rb

Constant Summary collapse

PERMISSION_BITMASK = 
0007777

Class Method Summary collapse

Class Method Details

.format_checksum(checksum) ⇒ Object 



25
26
27
28
29
 
# File 'lib/mini_tarball/header_formatter.rb', line 25

def self.format_checksum(checksum)
  length = Header::FIELDS[:checksum][:length]

  checksum ? format_number(checksum, length - 1) << "\0 " : " " * length
end

.format_number(value, length) ⇒ Object

Parameters:

  • value (Integer)
  • length (Integer)

Raises:

  • (NotImplementedError) 


11
12
13
14
15
16
 
# File 'lib/mini_tarball/header_formatter.rb', line 11

def self.format_number(value, length)
  return nil if !value
  raise NotImplementedError.new("Negative numbers are not supported") if value.negative?

  fits_into_octal?(value, length) ? to_octal(value, length) : to_base256(value, length)
end

.format_permissions(value, length) ⇒ Object

Removes file type bitfields and returns file permissions as formatted number

Parameters:

  • value (Integer)
  • length (Integer) 


21
22
23
 
# File 'lib/mini_tarball/header_formatter.rb', line 21

def self.format_permissions(value, length)
  format_number(value & PERMISSION_BITMASK, length)
end

.zero_pad(binary) ⇒ Object 



31
32
33
34
 
# File 'lib/mini_tarball/header_formatter.rb', line 31

def self.zero_pad(binary)
  padding_length = (Header::BLOCK_SIZE - binary.length) % Header::BLOCK_SIZE
  binary << "\0" * padding_length
end