Class: Podoff::Document

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

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(s, encoding) ⇒ Document

Returns a new instance of Document.



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# File 'lib/podoff.rb', line 47

def initialize(s, encoding)

  fail ArgumentError.new('not a PDF file') \
    unless s.match(/\A%PDF-\d+\.\d+\s/)

  @encoding = encoding

  @scanner = ::StringScanner.new(s)
  @version = nil
  @xref = nil
  @objs = {}
  @obj_counters = {}
  @root = nil

  @additions = {}

  @version = @scanner.scan(/%PDF-\d+\.\d+/)

  loop do

    @scanner.skip_until(
      /(startxref\s+\d+|\d+\s+\d+\s+obj|\/Root\s+\d+\s+\d+\s+R)/)

    m = @scanner.matched
    break unless m

    if m[0] == 's'
      @xref = m.split(' ').last.to_i
    elsif m[0] == '/'
      @root = extract_ref(m)
    else
      obj = Podoff::Obj.extract(self)
      @objs[obj.ref] = obj
      @obj_counters[obj.ref] = (@obj_counters[obj.ref] || 0) + 1
    end
  end

  if @root == nil
    @scanner.pos = 0
    loop do
      @scanner.skip_until(/\/Root\s+\d+\s+\d+\s+R/)
      break unless @scanner.matched
      @root = extract_ref(@scanner.matched)
    end
  end
end

Instance Attribute Details

#additions ⇒ Object (readonly)

Returns the value of attribute additions.



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# File 'lib/podoff.rb', line 45

def additions
  @additions
end

#encoding ⇒ Object (readonly)

Returns the value of attribute encoding.



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# File 'lib/podoff.rb', line 36

def encoding
  @encoding
end

#obj_counters ⇒ Object (readonly)

Returns the value of attribute obj_counters.



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# File 'lib/podoff.rb', line 42

def obj_counters
  @obj_counters
end

#objs ⇒ Object (readonly)

Returns the value of attribute objs.



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# File 'lib/podoff.rb', line 41

def objs
  @objs
end

#root ⇒ Object (readonly)

Returns the value of attribute root.



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# File 'lib/podoff.rb', line 43

def root
  @root
end

#scanner ⇒ Object (readonly)

Returns the value of attribute scanner.



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# File 'lib/podoff.rb', line 38

def scanner
  @scanner
end

#version ⇒ Object (readonly)

Returns the value of attribute version.



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# File 'lib/podoff.rb', line 39

def version
  @version
end

#xref ⇒ Object (readonly)

Returns the value of attribute xref.



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# File 'lib/podoff.rb', line 40

def xref
  @xref
end

Class Method Details

.load(path, encoding) ⇒ Object 



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# File 'lib/podoff.rb', line 23

def self.load(path, encoding)

  Podoff::Document.new(
    File.open(path, 'rb:' + encoding) { |f| f.read },
    encoding
  )
end

.parse(s) ⇒ Object 



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# File 'lib/podoff.rb', line 31

def self.parse(s)

  Podoff::Document.new(s)
end

Instance Method Details

#add(obj) ⇒ Object 



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# File 'lib/podoff.rb', line 160

def add(obj)

  @objs[obj.ref] = obj
  @additions[obj.ref] = obj

  obj
end

#add_base_font(name) ⇒ Object 



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# File 'lib/podoff.rb', line 168

def add_base_font(name)

  name = name[1..-1] if name[0] == '/'

  r = new_ref
  s = "#{r} obj <</Type /Font /Subtype /Type1 /BaseFont /#{name}>> endobj"

  add(Obj.new(self, r, source: s))
end

#add_stream(src = nil, &block) ⇒ Object 



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# File 'lib/podoff.rb', line 178

def add_stream(src=nil, &block)

  ref = new_ref

  src =
    src &&
    [
      "#{ref} obj",
      "<< /Length #{src.size} >>\nstream\n#{src}\nendstream",
      "endobj"
    ].join("\n")

  str =
    src ?
    nil :
    make_stream(&block)

  obj = add(Obj.new(self, ref, source: src, stream: str))

  str || obj
end

#dup ⇒ Object 



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# File 'lib/podoff.rb', line 104

def dup

  o = self

  self.class.allocate.instance_eval do

    @encoding = o.encoding

    @scanner = ::StringScanner.new(o.source)
    @xref = o.xref

    @objs = o.objs.inject({}) { |h, (k, v)| h[k] = v.dup(self); h }
    @obj_counters = o.obj_counters.dup

    @root = o.root

    @additions =
      o.additions.inject({}) { |h, (k, v)| h[k] = v.dup(self); h }

    self
  end
end

#new_ref ⇒ Object 



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# File 'lib/podoff.rb', line 153

def new_ref

  "#{
    @objs.keys.inject(-1) { |i, r| [ i, r.split(' ').first.to_i ].max } + 1
  } 0"
end

#page(index) ⇒ Object 



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# File 'lib/podoff.rb', line 142

def page(index)

  if index < 0
    pages[index]
  elsif index == 0
    nil
  else
    pages[index - 1]
  end
end

#pages ⇒ Object 



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# File 'lib/podoff.rb', line 127

def pages

  #@objs.values.select { |o| o.type == '/Page' }

  ps = @objs.values.find { |o| o.type == '/Pages' }

  fail ArgumentError.new(
    "no /Pages, the PDF is not usable by Podoff as is, you have to do " +
    "`qpdf --object-streams=disable original.pdf unpacked.pdf` " +
    "and use unpacked.pdf instead of original.pdf"
  ) unless ps

  extract_refs(ps.attributes[:kids]).collect { |r| @objs[r] }
end

#re_add(obj_or_ref) ⇒ Object 



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# File 'lib/podoff.rb', line 200

def re_add(obj_or_ref)

  obj = obj_or_ref.is_a?(String) ? @objs[obj_or_ref] : obj_or_ref

  obj = obj.replicate unless obj.replica?

  add(obj)
end

#rewrite(path = :string, encoding = nil) ⇒ Object 



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# File 'lib/podoff.rb', line 254

def rewrite(path=:string, encoding=nil)

  encoding ||= @encoding

  f =
    case path
      when :string, '-' then StringIO.new
      when String then File.open(path, 'wb')
      else path
    end
  f.set_encoding(encoding)

  v = source.match(/%PDF-\d+\.\d+/)[0]
  f.write(v)
  f.write("\n")

  pointers = {}

  objs.keys.sort.each do |k|
    pointers[k.split(' ').first.to_i] = f.pos
    f.write(objs[k].source.force_encoding(encoding))
    f.write("\n")
  end

  xref = f.pos

  write_xref(f, pointers)

  f.write("trailer\n")
  f.write("<<\n")
  f.write("/Size #{objs.size + 1}\n")
  f.write("/Root #{root} R\n")
  f.write(">>\n")
  f.write("startxref #{xref}\n")
  f.write("%%EOF\n")

  f.close if path.is_a?(String) || path.is_a?(Symbol)

  f.is_a?(StringIO) ? f.string : nil
end

#source ⇒ Object 



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# File 'lib/podoff.rb', line 94

def source

  @scanner.string
end

#updated? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/podoff.rb', line 99

def updated?

  @additions.any?
end

#write(path = :string, encoding = nil) ⇒ Object 



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# File 'lib/podoff.rb', line 209

def write(path=:string, encoding=nil)

  encoding ||= @encoding

  f =
    case path
      when :string, '-' then StringIO.new
      when String then File.open(path, 'wb')
      else path
    end
  f.set_encoding(encoding) # internal encoding: nil
  #f.set_encoding(encoding, encoding)

  f.write(source)

  if @additions.any?

    pointers = {}

    @additions.values.each do |o|
      f.write("\n")
      pointers[o.ref.split(' ').first.to_i] = f.pos
      f.write(o.to_s.force_encoding(encoding))
    end
    f.write("\n\n")

    xref = f.pos

    write_xref(f, pointers)

    f.write("trailer\n")
    f.write("<<\n")
    f.write("/Prev #{self.xref}\n")
    f.write("/Size #{objs.size + 1}\n")
    f.write("/Root #{root} R\n")
    f.write(">>\n")
    f.write("startxref #{xref}\n")
    f.write("%%EOF\n")
  end

  f.close if path.is_a?(String) || path.is_a?(Symbol)

  f.is_a?(StringIO) ? f.string : nil
end