Class: ZipTricks::Manifest

Inherits:
Struct
  • Object
show all
Defined in:
lib/zip_tricks/manifest.rb

Overview

Helps to estimate archive sizes

Defined Under Namespace

Classes: ZipSpan

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#io ⇒ Object

Returns the value of attribute io

Returns:

  • (Object) —

    the current value of io



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# File 'lib/zip_tricks/manifest.rb', line 2

def io
  @io
end

#part_list ⇒ Object

Returns the value of attribute part_list

Returns:

  • (Object) —

    the current value of part_list



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# File 'lib/zip_tricks/manifest.rb', line 2

def part_list
  @part_list
end

#zip_streamer ⇒ Object

Returns the value of attribute zip_streamer

Returns:

  • (Object) —

    the current value of zip_streamer



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# File 'lib/zip_tricks/manifest.rb', line 2

def zip_streamer
  @zip_streamer
end

Class Method Details

.build {|Manifest| ... } ⇒ Array<ZipSpan>, Fixnum

Builds an array of spans within the ZIP file and computes the size of the resulting archive in bytes.

zip_spans, bytesize = Manifest.build do | b |
  b.add_stored_entry(name: "file.doc", size: 898291)
  b.add_compressed_entry(name: "family.tif", size: 89281911, compressed_size: 121908)
end
bytesize #=> ... (Fixnum or Bignum)
zip_spans[0] #=> Manifest::ZipSpan(part_type: :entry_header, byte_range_in_zip: 0..44, ...)
zip_spans[-1] #=> Manifest::ZipSpan(part_type: :central_directory, byte_range_in_zip: 776721..898921, ...)

Yields:

  • (Manifest) —

    the manifest object you can add entries to

Returns:

  • (Array<ZipSpan>, Fixnum) —

    an array of byte spans within the final ZIP, and the total size of the archive



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# File 'lib/zip_tricks/manifest.rb', line 20

def self.build
  output_io = ZipTricks::WriteAndTell.new(ZipTricks::NullWriter)
  part_list = []
  last_range_end = 0
  ZipTricks::Streamer.open(output_io) do | zip_streamer |
    manifest = new(zip_streamer, output_io, part_list)
    yield(manifest)
    last_range_end = part_list[-1].byte_range_in_zip.end
  end

  # Record the position of the central directory
  directory_location = (last_range_end + 1)..(output_io.tell - 1)
  part_list << ZipSpan.new(:central_directory, directory_location, :central_directory, nil)

  [part_list, output_io.tell]
end

Instance Method Details

#add_compressed_entry(name:, size_uncompressed:, size_compressed:, segment_info: nil) ⇒ Object

Add a fake entry to the archive, to see how big it is going to be in the end.

Parameters:

  • name (String) —

    the name of the file (filenames are variable-width in the ZIP)

  • size_uncompressed (Fixnum) —

    size of the uncompressed entry

  • size_compressed (Fixnum) —

    size of the compressed entry

  • segment_info (Object) (defaults to: nil) —

    if you need to save anything to retrieve later from the Manifest, pass it here (like the URL of the file)

Returns:

  • self



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# File 'lib/zip_tricks/manifest.rb', line 64

def add_compressed_entry(name:, size_uncompressed:, size_compressed:, segment_info: nil)
  register_part(:entry_header, name, segment_info) do
    zip_streamer.add_compressed_entry(name, size_uncompressed, C_fake_crc, size_compressed)
  end

  register_part(:entry_body, name, segment_info) do
    zip_streamer.simulate_write(size_compressed)
  end

  self
end

#add_stored_entry(name:, size_uncompressed:, segment_info: nil) ⇒ Object

Add a fake entry to the archive, to see how big it is going to be in the end.

Parameters:

  • name (String) —

    the name of the file (filenames are variable-width in the ZIP)

  • size_uncompressed (Fixnum) —

    size of the uncompressed entry

  • segment_info (Object) (defaults to: nil) —

    if you need to save anything to retrieve later from the Manifest, pass it here (like the URL of the file)

Returns:

  • self



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# File 'lib/zip_tricks/manifest.rb', line 44

def add_stored_entry(name:, size_uncompressed:, segment_info: nil)
  register_part(:entry_header, name, segment_info) do
    zip_streamer.add_stored_entry(name, size_uncompressed, C_fake_crc)
  end

  register_part(:entry_body, name, segment_info) do
    zip_streamer.simulate_write(size_uncompressed)
  end

  self
end