Class: Zipstream

Inherits:
Object
  • Object
show all
Defined in:
lib/zipstream.rb

Overview

Simple, streamable zip file creation

Defined Under Namespace

Classes: Body, FiberYieldingStream, Railtie

Constant Summary collapse

VERSION = 
File.read File.expand_path '../../VERSION', __FILE__
Fiber =

Use native Fibers if available

Fiber

Instance Method Summary collapse

Constructor Details

#initialize(stream, options = {}) ⇒ Zipstream

Returns a new instance of Zipstream.



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# File 'lib/zipstream.rb', line 8

def initialize stream, options={}
  @stream = stream
  @length = 0
  @directory = ""
  @directory_count = 0
  @directory_length = 0
  @options = options
end

Instance Method Details

#close ⇒ Object

TODO: use storage large files



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# File 'lib/zipstream.rb', line 99

def close
  comment = @options[:comment].to_s || ""
  comment_length = comment.length

  @stream << @directory << [
    # end of central file header signature
    0x06054b50,
    # this disk number
    0x00,
    # number of disk with cdr
    0x00,
    # number of entries in the cdr on this disk
    @directory_count,
    # number of entries in the cdr
    @directory_count,
    # cdr size
    @directory_length,
    # cdr ofs
    @length,
    # zip file comment length
    comment_length,
  ].pack('Vv4V2v') << comment
end

#write(name, data, options = {}) ⇒ Object 



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# File 'lib/zipstream.rb', line 17

def write name, data, options={}
  # Fails without specifying the window bits (odd!)
  deflater = Zlib::Deflate.new Zlib::BEST_COMPRESSION, -Zlib::MAX_WBITS
  zdata = deflater.deflate data, Zlib::FINISH
  deflater.close

  method = 0x08
  timestamp = dostime options[:datetime] || DateTime.now
  crc = Zlib.crc32 data
  zdata_length = zdata.length
  data_length = data.length
  name = name.to_s
  name_length = name.length
  comment = options[:comment].to_s || ""
  comment_length = comment.length

  @directory << [
    # central file header signature
    0x02014b50,
    # version made by
    (6 << 8) + 3,
    # version needed to extract
    (6 << 8) + 3,
    # general purpose bit flag
    0x00,
    # compresion method (deflate or store)
    method,
    # dos timestamp
    timestamp,
    # crc32 of data
    crc,
    # compressed data length
    zdata_length,
    # uncompressed data length
    data_length,
    # filename length
    name_length,
    # extra data len
    0,
    # file comment length
    comment_length,
    # disk number start
    0,
    # internal file attributes
    0,
    # external file attributes
    32,
    # relative offset of local header
    @length,
  ].pack('Vv4V4v5V2') << name << comment
  @directory_length += 46 + name_length + comment_length
  @directory_count += 1

  @stream << [
    # local file header signature
    0x04034b50,
    # version needed to extract
    (6 << 8) + 3,
    # general purpose bit flag
    0x00,
    # compresion method (deflate or store)
    method,
    # dos timestamp
    timestamp,
    # checksum of data
    crc,
    # compressed data length
    zdata_length,
    # uncompressed data length
    data_length,
    # filename length
    name_length,
    # extra data len
    0,
  ].pack('Vv3V4v2') << name << zdata
  @length += 30 + name_length + zdata_length
end