Class: Omnizip::Formats::Iso::PathTable

Inherits:
Object
  • Object
show all
Defined in:
lib/omnizip/formats/iso/path_table.rb

Overview

ISO 9660 Path Table Provides efficient directory hierarchy lookup

Defined Under Namespace

Classes: Entry

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ PathTable

Initialize path table



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# File 'lib/omnizip/formats/iso/path_table.rb', line 49

def initialize
  @entries = []
end

Instance Attribute Details

#entries ⇒ Object (readonly)

Returns the value of attribute entries.



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# File 'lib/omnizip/formats/iso/path_table.rb', line 9

def entries
  @entries
end

Class Method Details

.parse(data, size) ⇒ PathTable

Parse path table from binary data

Parameters:

  • data (String) —

    Binary path table data

  • size (Integer) —

    Size of path table in bytes

Returns:



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# File 'lib/omnizip/formats/iso/path_table.rb', line 58

def self.parse(data, size)
  new.tap { |pt| pt.parse(data, size) }
end

Instance Method Details

#find_by_location(location) ⇒ Entry?

Find entry by location

Parameters:

  • location (Integer) —

    LBA location

Returns:

  • (Entry, nil) —

    Found entry or nil



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# File 'lib/omnizip/formats/iso/path_table.rb', line 112

def find_by_location(location)
  @entries.find { |e| e.location == location }
end

#find_by_name(name) ⇒ Entry?

Find entry by directory name

Parameters:

  • name (String) —

    Directory name

Returns:

  • (Entry, nil) —

    Found entry or nil



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# File 'lib/omnizip/formats/iso/path_table.rb', line 104

def find_by_name(name)
  @entries.find { |e| e.name == name }
end

#parse(data, size) ⇒ Object

Parse path table data

Parameters:

  • data (String) —

    Binary data

  • size (Integer) —

    Size in bytes



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# File 'lib/omnizip/formats/iso/path_table.rb', line 66

def parse(data, size)
  offset = 0

  while offset < size
    # Byte 0: Length of directory identifier
    name_length = data.getbyte(offset)
    break if name_length.zero?

    # Byte 1: Extended attribute record length
    data.getbyte(offset + 1)

    # Bytes 2-5: Location of extent (little-endian)
    location = data[offset + 2, 4].unpack1("V")

    # Bytes 6-7: Parent directory number
    parent = data[offset + 6, 2].unpack1("v")

    # Bytes 8+: Directory identifier
    name = data[offset + 8, name_length].strip

    # Handle root directory (zero-length name)
    name = "/" if name.empty?

    # Create entry
    @entries << Entry.new(name, location, parent)

    # Move to next entry
    # Length is 8 + name_length, padded to even boundary
    record_length = 8 + name_length
    record_length += 1 if record_length.odd?
    offset += record_length
  end
end

#root ⇒ Entry

Get root directory entry

Returns:



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# File 'lib/omnizip/formats/iso/path_table.rb', line 119

def root
  @entries.first
end