Class: PDF::Core::Stream

Inherits:
Object
  • Object
show all
Defined in:
lib/pdf/core/stream.rb

Overview

PDF Stream object

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(io = nil) ⇒ Stream

Returns a new instance of Stream.

Parameters:

  • io (String) (defaults to: nil) —

    must be mutable

Source Code
lib/pdf/core/stream.rb, line 18
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def initialize(io = nil)

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  @filtered_stream = ''

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  @stream = io

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  @filters = FilterList.new

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end

Instance Attribute Details

#filters ⇒ PDF::Core::FilterList (readonly)

Stream filters

Returns:

Source Code
lib/pdf/core/stream.rb, line 15
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def filters

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  @filters

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end

Instance Method Details

#<<(io) ⇒ self

Append data to stream.

Parameters:

  • io (String)

Returns:

  • (self)
Source Code
lib/pdf/core/stream.rb, line 28
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def <<(io)

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  (@stream ||= +'') << io

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  @filtered_stream = nil

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  self

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end

#compress! ⇒ void

This method returns an undefined value.

Set up stream to be compressed when serialized.

Source Code
lib/pdf/core/stream.rb, line 37
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def compress!

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  unless @filters.names.include?(:FlateDecode)

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    @filtered_stream = nil

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    @filters << :FlateDecode

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  end

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end

#compressed? ⇒ Boolean

Is this stream compressed?

Returns:

  • (Boolean)
Source Code
lib/pdf/core/stream.rb, line 47
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def compressed?

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  @filters.names.include?(:FlateDecode)

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end

#data ⇒ Hash

Stream dictionary

Returns:

  • (Hash)
Source Code
lib/pdf/core/stream.rb, line 99
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def data

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  if @stream

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    filter_names = @filters.names

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    filter_params = @filters.decode_params

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    d = {

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      Length: filtered_stream.length,

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    }

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    if filter_names.any?

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      d[:Filter] = filter_names

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    end

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    if filter_params.any? { |f| !f.nil? }

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      d[:DecodeParms] = filter_params

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    end

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    d

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  else

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    {}

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  end

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end







    
      

  

  
    #empty?  ⇒ Boolean 
  

  

  


  

    
Is there any data in this stream?



  





  


Returns:


    
  
    
  • 
      
      
        (Boolean)
      
      
      
    
    • 
  







  Source Code
  
lib/pdf/core/stream.rb, line 54

  
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def empty?

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  @stream.nil?

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end







    
      

  

  
    #filtered_stream  ⇒ Stream 
  

  

  


  

    
Stream data with filters applied.



  





  


Returns:







  Source Code
  
lib/pdf/core/stream.rb, line 61

  
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def filtered_stream

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  if @stream

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    if @filtered_stream.nil?

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      @filtered_stream = @stream.dup

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      @filters.each do |(filter_name, params)|

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        filter = PDF::Core::Filters.const_get(filter_name)

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        if filter

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          @filtered_stream = filter.encode(@filtered_stream, params)

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        end

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      end

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    end

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    @filtered_stream

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  end

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end







    
      

  

  
    #inspect  ⇒ String 
  

  

  


  

    
String representation of the stream for debugging purposes.



  





  


Returns:


    
  
    
  • 
      
      
        (String)
      
      
      
    
    • 
  







  Source Code
  
lib/pdf/core/stream.rb, line 123

  
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def inspect

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  format(

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    '#<%<class>s:0x%<object_id>014x @stream=%<stream>s, @filters=%<filters>s>',

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    class: self.class.name,

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    object_id: object_id,

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    stream: @stream.inspect,

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    filters: @filters.inspect,

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  )

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end







    
      

  

  
    #length  ⇒ Integer 
  

  

  


  

    
Size of data in the stream



  





  


Returns:


    
  
    
  • 
      
      
        (Integer)
      
      
      
    
    • 
  







  Source Code
  
lib/pdf/core/stream.rb, line 81

  
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def length

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  @stream.length

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end







    
      

  

  
    #object  ⇒ String 
  

  

  


  

    
Serialized stream data



  





  


Returns:


    
  
    
  • 
      
      
        (String)
      
      
      
    
    • 
  







  Source Code
  
lib/pdf/core/stream.rb, line 88

  
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def object

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  if filtered_stream

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    "stream\n#{filtered_stream}\nendstream\n"

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  else

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    ''

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  end

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end