Class: Omnizip::Formats::Zip::Zip64ExtraField

Inherits:
Object
  • Object
show all
Includes:
Constants
Defined in:
lib/omnizip/formats/zip/zip64_extra_field.rb

Overview

ZIP64 Extended Information Extra Field Used in local/central headers when sizes exceed 32-bit limits

Constant Summary

Constants included from Constants

Constants::ATTR_ARCHIVE, Constants::ATTR_DIRECTORY, Constants::CENTRAL_DIRECTORY_SIGNATURE, Constants::COMPRESSION_BZIP2, Constants::COMPRESSION_DEFLATE, Constants::COMPRESSION_DEFLATE64, Constants::COMPRESSION_IMPLODED, Constants::COMPRESSION_LZMA, Constants::COMPRESSION_PPMD, Constants::COMPRESSION_REDUCED_1, Constants::COMPRESSION_REDUCED_2, Constants::COMPRESSION_REDUCED_3, Constants::COMPRESSION_REDUCED_4, Constants::COMPRESSION_SHRUNK, Constants::COMPRESSION_STORE, Constants::COMPRESSION_ZSTANDARD, Constants::DATA_DESCRIPTOR_SIGNATURE, Constants::END_OF_CENTRAL_DIRECTORY_SIGNATURE, Constants::FLAG_DATA_DESCRIPTOR, Constants::FLAG_ENCRYPTED, Constants::FLAG_STRONG_ENCRYPTION, Constants::FLAG_UTF8, Constants::LOCAL_FILE_HEADER_SIGNATURE, Constants::MAX_COMMENT_LENGTH, Constants::UNIX_DIR_PERMISSIONS, Constants::UNIX_EXTRA_FIELD_TAG, Constants::UNIX_FILE_PERMISSIONS, Constants::UNIX_SYMLINK_PERMISSIONS, Constants::VERSION_BZIP2, Constants::VERSION_DEFAULT, Constants::VERSION_DEFLATE, Constants::VERSION_LZMA, Constants::VERSION_MADE_BY_UNIX, Constants::VERSION_MADE_BY_WINDOWS, Constants::VERSION_ZIP64, Constants::ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR_SIGNATURE, Constants::ZIP64_END_OF_CENTRAL_DIRECTORY_SIGNATURE, Constants::ZIP64_EXTRA_FIELD_TAG, Constants::ZIP64_LIMIT

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(tag: ZIP64_EXTRA_FIELD_TAG, uncompressed_size: nil, compressed_size: nil, relative_header_offset: nil, disk_start_number: nil) ⇒ Zip64ExtraField

Returns a new instance of Zip64ExtraField.



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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 14

def initialize(
  tag: ZIP64_EXTRA_FIELD_TAG,
  uncompressed_size: nil,
  compressed_size: nil,
  relative_header_offset: nil,
  disk_start_number: nil
)
  @tag = tag
  @uncompressed_size = uncompressed_size
  @compressed_size = compressed_size
  @relative_header_offset = relative_header_offset
  @disk_start_number = disk_start_number
  @size = calculate_size
end

Instance Attribute Details

#compressed_size ⇒ Object

Returns the value of attribute compressed_size.



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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 11

def compressed_size
  @compressed_size
end

#disk_start_number ⇒ Object

Returns the value of attribute disk_start_number.



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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 11

def disk_start_number
  @disk_start_number
end

#relative_header_offset ⇒ Object

Returns the value of attribute relative_header_offset.



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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 11

def relative_header_offset
  @relative_header_offset
end

#size ⇒ Object

Returns the value of attribute size.



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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 11

def size
  @size
end

#tag ⇒ Object

Returns the value of attribute tag.



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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 11

def tag
  @tag
end

#uncompressed_size ⇒ Object

Returns the value of attribute uncompressed_size.



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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 11

def uncompressed_size
  @uncompressed_size
end

Class Method Details

.from_binary(data, needs_uncompressed: false, needs_compressed: false, needs_offset: false, needs_disk: false) ⇒ Object

Parse from binary data needs_uncompressed, needs_compressed, needs_offset, needs_disk specify which fields should be present based on the regular header values



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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 47

def self.from_binary(data, needs_uncompressed: false, needs_compressed: false,
                    needs_offset: false, needs_disk: false)
  tag, = data.unpack("vv")

  unless tag == ZIP64_EXTRA_FIELD_TAG
    raise Omnizip::FormatError,
          "Invalid ZIP64 extra field tag"
  end

  offset = 4 # After tag and size
  uncompressed_size = nil
  compressed_size = nil
  relative_header_offset = nil
  disk_start_number = nil

  # Read fields in order based on what's needed
  if needs_uncompressed && offset + 8 <= data.bytesize
    uncompressed_size = data[offset, 8].unpack1("Q")
    offset += 8
  end

  if needs_compressed && offset + 8 <= data.bytesize
    compressed_size = data[offset, 8].unpack1("Q")
    offset += 8
  end

  if needs_offset && offset + 8 <= data.bytesize
    relative_header_offset = data[offset, 8].unpack1("Q")
    offset += 8
  end

  if needs_disk && offset + 4 <= data.bytesize
    disk_start_number = data[offset, 4].unpack1("V")
  end

  new(
    tag: tag,
    uncompressed_size: uncompressed_size,
    compressed_size: compressed_size,
    relative_header_offset: relative_header_offset,
    disk_start_number: disk_start_number,
  )
end

.needed?(uncompressed_size: 0, compressed_size: 0, offset: 0) ⇒ Boolean

Check if this extra field is needed

Returns:

  • (Boolean) 


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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 92

def self.needed?(uncompressed_size: 0, compressed_size: 0, offset: 0)
  uncompressed_size >= ZIP64_LIMIT ||
    compressed_size >= ZIP64_LIMIT ||
    offset >= ZIP64_LIMIT
end

Instance Method Details

#to_binary ⇒ Object

Serialize to binary format



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# File 'lib/omnizip/formats/zip/zip64_extra_field.rb', line 30

def to_binary
  @size = calculate_size
  data = [tag, size].pack("vv")

  # Fields are included in the order they're needed
  # based on which values in the regular header are 0xFFFFFFFF
  data << [uncompressed_size].pack("Q") if uncompressed_size
  data << [compressed_size].pack("Q") if compressed_size
  data << [relative_header_offset].pack("Q") if relative_header_offset
  data << [disk_start_number].pack("V") if disk_start_number

  data
end