Class: Origami::XRef

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

Overview

Class representing a Cross-reference information.

Defined Under Namespace

Classes: InvalidXRefSectionError, InvalidXRefSubsectionError, Section, Subsection

Constant Summary collapse

FREE = 
"f"
USED = 
"n"
FIRSTFREE = 
65535
@@regexp = 
/(\d{10}) (\d{5}) (n|f)(\r\n| \r| \n)/

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(offset, generation, state) ⇒ XRef

Creates a new XRef.

offset

The file offset of the referenced Object.

generation

The generation number of the referenced Object.

state

The state of the referenced Object (FREE or USED).



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# File 'lib/origami/xreftable.rb', line 82

def initialize(offset, generation, state)
  @offset, @generation, @state = offset, generation, state
end

Instance Attribute Details

#generation ⇒ Object

Returns the value of attribute generation.



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# File 'lib/origami/xreftable.rb', line 74

def generation
  @generation
end

#offset ⇒ Object

Returns the value of attribute offset.



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# File 'lib/origami/xreftable.rb', line 74

def offset
  @offset
end

#state ⇒ Object

Returns the value of attribute state.



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# File 'lib/origami/xreftable.rb', line 74

def state
  @state
end

Class Method Details

.parse(stream) ⇒ Object

:nodoc:



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# File 'lib/origami/xreftable.rb', line 86

def self.parse(stream) #:nodoc:
  
  if stream.scan(@@regexp).nil?
    raise InvalidXRefError, "Invalid XRef format"
  end
  
  offset = stream[1].to_i
  generation = stream[2].to_i
  state = stream[3]
  
  XRef.new(offset, generation, state)
end

Instance Method Details

#to_s ⇒ Object

Outputs self into PDF code.



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# File 'lib/origami/xreftable.rb', line 102

def to_s
  off = ("0" * (10 - @offset.to_s.length)) + @offset.to_s
  gen = ("0" * (5 - @generation.to_s.length)) + @generation.to_s
  
  "#{off} #{gen} #{@state}" + EOL
end

#to_xrefstm_data(type_w, field1_w, field2_w) ⇒ Object 



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# File 'lib/origami/xreftable.rb', line 109

def to_xrefstm_data(type_w, field1_w, field2_w)
  type_w <<= 3
  field1_w <<= 3
  field2_w <<= 3

  type = ((@state == FREE) ? "\000" : "\001").unpack("B#{type_w}")[0]

  offset = @offset.to_s(2)
  offset = '0' * (field1_w - offset.size) + offset
  generation = @generation.to_s(2)

  generation = '0' * (field2_w - generation.size) + generation

  [ type , offset, generation ].pack("B#{type_w}B#{field1_w}B#{field2_w}")
end