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 = 
/(?<offset>\d{10}) (?<gen>\d{5}) (?<state>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 66

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 58

def generation
  @generation
end

#offset ⇒ Object

Returns the value of attribute offset.



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# File 'lib/origami/xreftable.rb', line 58

def offset
  @offset
end

#state ⇒ Object

Returns the value of attribute state.



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# File 'lib/origami/xreftable.rb', line 58

def state
  @state
end

Class Method Details

.parse(stream) ⇒ Object

:nodoc:



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# File 'lib/origami/xreftable.rb', line 70

def self.parse(stream) #:nodoc:
    scanner = Parser.init_scanner(stream)

    if scanner.scan(@@regexp).nil?
        raise InvalidXRefError, "Invalid XRef format"
    end

    offset = scanner['offset'].to_i
    generation = scanner['gen'].to_i
    state = scanner['state']

    XRef.new(offset, generation, state)
end

Instance Method Details

#free! ⇒ Object

Marks an XRef as freed.



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# File 'lib/origami/xreftable.rb', line 101

def free!
    @state = FREE
end

#free? ⇒ Boolean

Returns true if the associated object is freed.

Returns:



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# File 'lib/origami/xreftable.rb', line 94

def free?
    @state == FREE
end

#to_s(eol: $/) ⇒ Object

Outputs self into PDF code.



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# File 'lib/origami/xreftable.rb', line 108

def to_s(eol: $/)
    off = @offset.to_s.rjust(10, '0')
    gen = @generation.to_s.rjust(5, '0')

    "#{off} #{gen} #{@state}" + eol.rjust(2, ' ')
end

#to_xrefstm_data(type_w, field1_w, field2_w) ⇒ Object 



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# File 'lib/origami/xreftable.rb', line 115

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).rjust(field1_w, '0')
    generation = @generation.to_s(2).rjust(field2_w, '0')

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

#used? ⇒ Boolean

Returns true if the associated object is used.

Returns:



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# File 'lib/origami/xreftable.rb', line 87

def used?
    @state == USED
end