Class: Mapi::Pst::Header

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

Overview

class which encapsulates the pst header

Constant Summary collapse

SIZE = 
512
MAGIC = 
0x2142444e
INDEX_TYPE_OFFSET =

these are the constants defined in libpst.c, that are referenced in pst_open()

0x0A
FILE_SIZE_POINTER = 
0xA8
FILE_SIZE_POINTER_64 = 
0xB8
SECOND_POINTER = 
0xBC
INDEX_POINTER = 
0xC4
SECOND_POINTER_64 = 
0xE0
INDEX_POINTER_64 = 
0xF0
ENC_OFFSET = 
0x1CD

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ Header

Returns a new instance of Header.



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# File 'lib/mapi/pst.rb', line 126

def initialize data
	@magic = data.unpack('N')[0]
	@index_type = data[INDEX_TYPE_OFFSET]
	@version = {0x0e => 1997, 0x17 => 2003}[@index_type]

	if version_2003?
		# don't know?
		# >> data1.unpack('V*').zip(data2.unpack('V*')).enum_with_index.select { |(c, d), i| c != d and not [46, 56, 60].include?(i) }.select { |(a, b), i| b == 0 }.map { |(a, b), i| [a / 256, i] }
		#   [8, 76], [32768, 84], [128, 89]
		# >> data1.unpack('C*').zip(data2.unpack('C*')).enum_with_index.select { |(c, d), i| c != d and not [184..187, 224..227, 240..243].any? { |r| r === i } }.select { |(a, b), i| b == 0 and ((Math.log(a) / Math.log(2)) % 1) < 0.0001 }
		#   [[[2, 0], 61], [[2, 0], 76], [[2, 0], 195], [[2, 0], 257], [[8, 0], 305], [[128, 0], 338], [[128, 0], 357]]
		# i have only 2 psts to base this guess on, so i can't really come up with anything that looks reasonable yet. not sure what the offset is. unfortunately there is so much in the header
		# that isn't understood...
		@encrypt_type = 1

		@index2_count, @index2 = data[SECOND_POINTER_64 - 4, 8].unpack('V2')
		@index1_count, @index1 = data[INDEX_POINTER_64  - 4, 8].unpack('V2')

		@size = data[FILE_SIZE_POINTER_64, 4].unpack('V')[0]
	else
		@encrypt_type = data[ENC_OFFSET]

		@index2_count, @index2 = data[SECOND_POINTER - 4, 8].unpack('V2')
		@index1_count, @index1 = data[INDEX_POINTER  - 4, 8].unpack('V2')

		@size = data[FILE_SIZE_POINTER, 4].unpack('V')[0]
	end

	validate!
end

Instance Attribute Details

#encrypt_type ⇒ Object (readonly)

Returns the value of attribute encrypt_type.



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# File 'lib/mapi/pst.rb', line 123

def encrypt_type
  @encrypt_type
end

#index1 ⇒ Object (readonly)

Returns the value of attribute index1.



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# File 'lib/mapi/pst.rb', line 124

def index1
  @index1
end

#index1_count ⇒ Object (readonly)

Returns the value of attribute index1_count.



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# File 'lib/mapi/pst.rb', line 124

def index1_count
  @index1_count
end

#index2 ⇒ Object (readonly)

Returns the value of attribute index2.



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# File 'lib/mapi/pst.rb', line 124

def index2
  @index2
end

#index2_count ⇒ Object (readonly)

Returns the value of attribute index2_count.



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# File 'lib/mapi/pst.rb', line 124

def index2_count
  @index2_count
end

#index_type ⇒ Object (readonly)

Returns the value of attribute index_type.



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# File 'lib/mapi/pst.rb', line 123

def index_type
  @index_type
end

#magic ⇒ Object (readonly)

Returns the value of attribute magic.



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# File 'lib/mapi/pst.rb', line 123

def magic
  @magic
end

#size ⇒ Object (readonly)

Returns the value of attribute size.



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# File 'lib/mapi/pst.rb', line 123

def size
  @size
end

#version ⇒ Object (readonly)

Returns the value of attribute version.



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# File 'lib/mapi/pst.rb', line 125

def version
  @version
end

Instance Method Details

#encrypted? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mapi/pst.rb', line 161

def encrypted?
	encrypt_type != 0
end

#validate! ⇒ Object

Raises:



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# File 'lib/mapi/pst.rb', line 165

def validate!
	raise FormatError, "bad signature on pst file (#{'0x%x' % magic})" unless magic == MAGIC
	raise FormatError, "only index types 0x0e and 0x17 are handled (#{'0x%x' % index_type})" unless [0x0e, 0x17].include?(index_type)
	raise FormatError, "only encrytion types 0 and 1 are handled (#{encrypt_type.inspect})" unless [0, 1].include?(encrypt_type)
end

#version_2003? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mapi/pst.rb', line 157

def version_2003?
	version == 2003
end