Class: Higgs::Tar::ArchiveReader

Inherits:
IOHandler show all
Includes:
Enumerable
Defined in:
lib/higgs/tar.rb

Constant Summary

Constants included from Block

Block::AREGTYPE, Block::BLKSIZ, Block::BLKTYPE, Block::CHRTYPE, Block::CONTTYPE, Block::DIRTYPE, Block::EOA, Block::FIFOTYPE, Block::HEAD_FMT, Block::LNKTYPE, Block::MAGIC, Block::MAX_LEN, Block::REGTYPE, Block::SYMTYPE, Block::VERSION

Instance Method Summary collapse

Methods inherited from IOHandler

#initialize, #to_io

Methods included from Block

blocked_size, padding_size, tar?

Constructor Details

This class inherits a constructor from Higgs::Tar::IOHandler

Instance Method Details

#each(skip_body = false) ⇒ Object 



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# File 'lib/higgs/tar.rb', line 265

def each(skip_body=false)
  if (skip_body) then
    while (head = read_header(true))
      yield(head)
    end
  else
    while (head_and_body = fetch)
      yield(head_and_body)
    end
  end
  self
end

#fetch ⇒ Object 



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# File 'lib/higgs/tar.rb', line 242

def fetch
  head_and_body = read_header or return
  if (head_and_body[:size] > 0) then
    blocked_size = blocked_size(head_and_body[:size])
    head_and_body[:body] = @io.read(blocked_size)
    unless (head_and_body) then
      raise FormatError, 'unexpected EOF'
    end
    if (head_and_body[:body].size != blocked_size) then
      raise FormatError, 'mismatch body size'
    end
    head_and_body[:body][head_and_body[:size]...blocked_size] = ''
  else
    case (head_and_body[:typeflag])
    when REGTYPE, CONTTYPE
      head_and_body[:body] = ''
    else
      head_and_body[:body] = nil
    end
  end
  head_and_body
end

#read_header(skip_body = false) ⇒ Object 



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# File 'lib/higgs/tar.rb', line 187

def read_header(skip_body=false)
  head_data = @io.read(BLKSIZ)
  unless (head_data) then
    raise FormatError, 'unexpected EOF'
  end
  if (head_data.length != BLKSIZ) then
    raise FormatError, 'too short header'
  end
  if (head_data == EOA) then
    next_head_data = @io.read(BLKSIZ)
    if (next_head_data && next_head_data == EOA) then
      return nil
    else
      raise FormatError, "not of EOA: #{head_data.inspect}, #{next_head_data.inspect}"
    end
  end
  chksum = (head_data[0...148] + ' ' * 8 + head_data[156...BLKSIZ]).sum(20)
  head_list = head_data.unpack(HEAD_FMT)
  head = {}
  [ :name, :mode, :uid, :gid, :size, :mtime,
    :chksum, :typeflag, :linkname, :magic, :version,
    :uname, :gname, :devmajor, :devminor, :prefix
  ].each_with_index do |k, i|
    head[k] = head_list[i]
  end
  if (head[:typeflag] == AREGTYPE) then
    head[:typeflag] = REGTYPE
  end
  if (head[:magic] != MAGIC) then
    raise MagicError, "unknown format: #{head[:magic].inspect}"
  end
  # why?
  #if (head[:version] != VERSION) then
  #  raise VersionError, "unknown version: #{head[:version].inspect}"
  #end
  [ :mode,
    :uid,
    :gid,
    :size,
    :mtime,
    :chksum
  ].each do |sym|
    head[sym] = head[sym].oct
  end
  if (head[:chksum] != chksum) then
    raise CheckSumError, 'broken tar'
  end
  head[:mtime] = Time.at(head[:mtime])
  if (skip_body) then
    skip_size = head[:size] + padding_size(head[:size])
    @io.read(skip_size)
  end
  head
end