331 lines
9.5 KiB
Ruby
331 lines
9.5 KiB
Ruby
# coding: utf-8
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# typed: strict
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# frozen_string_literal: true
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################################################################################
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#
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# Copyright (C) 2006 Peter J Jones (pjones@pmade.com)
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# Copyright (C) 2011 James Healy
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#
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# Permission is hereby granted, free of charge, to any person obtaining
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# a copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be
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# included in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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#
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################################################################################
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require 'stringio'
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module PDF
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################################################################################
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# The Reader class serves as an entry point for parsing a PDF file.
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#
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# PDF is a page based file format. There is some data associated with the
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# document (metadata, bookmarks, etc) but all visible content is stored
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# under a Page object.
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#
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# In most use cases for extracting and examining the contents of a PDF it
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# makes sense to traverse the information using page based iteration.
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#
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# In addition to the documentation here, check out the
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# PDF::Reader::Page class.
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#
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# == File Metadata
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#
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# reader = PDF::Reader.new("somefile.pdf")
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#
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# puts reader.pdf_version
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# puts reader.info
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# puts reader.metadata
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# puts reader.page_count
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#
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# == Iterating over page content
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#
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# reader = PDF::Reader.new("somefile.pdf")
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#
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# reader.pages.each do |page|
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# puts page.fonts
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# puts page.images
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# puts page.text
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# end
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#
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# == Extracting all text
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#
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# reader = PDF::Reader.new("somefile.pdf")
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#
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# reader.pages.map(&:text)
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#
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# == Extracting content from a single page
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#
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# reader = PDF::Reader.new("somefile.pdf")
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#
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# page = reader.page(1)
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# puts page.fonts
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# puts page.images
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# puts page.text
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#
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# == Low level callbacks (ala current version of PDF::Reader)
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#
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# reader = PDF::Reader.new("somefile.pdf")
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#
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# page = reader.page(1)
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# page.walk(receiver)
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#
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# == Encrypted Files
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#
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# Depending on the algorithm it may be possible to parse an encrypted file.
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# For standard PDF encryption you'll need the :password option
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#
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# reader = PDF::Reader.new("somefile.pdf", :password => "apples")
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#
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class Reader
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# lowlevel hash-like access to all objects in the underlying PDF
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attr_reader :objects
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# creates a new document reader for the provided PDF.
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#
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# input can be an IO-ish object (StringIO, File, etc) containing a PDF
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# or a filename
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#
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# reader = PDF::Reader.new("somefile.pdf")
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#
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# File.open("somefile.pdf","rb") do |file|
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# reader = PDF::Reader.new(file)
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# end
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#
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# If the source file is encrypted you can provide a password for decrypting
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#
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# reader = PDF::Reader.new("somefile.pdf", :password => "apples")
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#
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# Using this method directly is supported, but it's more common to use
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# `PDF::Reader.open`
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#
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def initialize(input, opts = {})
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@cache = PDF::Reader::ObjectCache.new
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opts.merge!(:cache => @cache)
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@objects = PDF::Reader::ObjectHash.new(input, opts)
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end
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# Return a Hash with some basic information about the PDF file
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#
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def info
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dict = @objects.deref_hash(@objects.trailer[:Info]) || {}
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doc_strings_to_utf8(dict)
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end
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# Return a String with extra XML metadata provided by the author of the PDF file. Not
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# always present.
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#
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def metadata
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stream = @objects.deref_stream(root[:Metadata])
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if stream.nil?
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nil
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else
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xml = stream.unfiltered_data
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xml.force_encoding("utf-8")
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xml
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end
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end
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# To number of pages in this PDF
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#
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def page_count
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pages = @objects.deref_hash(root[:Pages])
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unless pages.kind_of?(::Hash)
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raise MalformedPDFError, "Pages structure is missing #{pages.class}"
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end
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@page_count ||= @objects.deref_integer(pages[:Count]) || 0
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end
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# The PDF version this file uses
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#
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def pdf_version
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@objects.pdf_version
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end
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# syntactic sugar for opening a PDF file and the most common approach. Accepts the
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# same arguments as new().
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#
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# PDF::Reader.open("somefile.pdf") do |reader|
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# puts reader.pdf_version
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# end
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#
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# or
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#
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# PDF::Reader.open("somefile.pdf", :password => "apples") do |reader|
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# puts reader.pdf_version
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# end
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#
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def self.open(input, opts = {}, &block)
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yield PDF::Reader.new(input, opts)
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end
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# returns an array of PDF::Reader::Page objects, one for each
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# page in the source PDF.
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#
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# reader = PDF::Reader.new("somefile.pdf")
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#
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# reader.pages.each do |page|
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# puts page.fonts
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# puts page.rectangles
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# puts page.text
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# end
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#
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# See the docs for PDF::Reader::Page to read more about the
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# methods available on each page
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#
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def pages
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return [] if page_count <= 0
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(1..self.page_count).map do |num|
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begin
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PDF::Reader::Page.new(@objects, num, :cache => @cache)
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rescue InvalidPageError
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raise MalformedPDFError, "Missing data for page: #{num}"
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end
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end
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end
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# returns a single PDF::Reader::Page for the specified page.
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# Use this instead of pages method when you need to access just a single
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# page
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#
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# reader = PDF::Reader.new("somefile.pdf")
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# page = reader.page(10)
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#
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# puts page.text
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#
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# See the docs for PDF::Reader::Page to read more about the
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# methods available on each page
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#
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def page(num)
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num = num.to_i
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if num < 1 || num > self.page_count
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raise InvalidPageError, "Valid pages are 1 .. #{self.page_count}"
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end
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PDF::Reader::Page.new(@objects, num, :cache => @cache)
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end
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private
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# recursively convert strings from outside a content stream into UTF-8
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#
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def doc_strings_to_utf8(obj)
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case obj
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when ::Hash then
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{}.tap { |new_hash|
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obj.each do |key, value|
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new_hash[key] = doc_strings_to_utf8(value)
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end
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}
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when Array then
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obj.map { |item| doc_strings_to_utf8(item) }
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when String then
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if has_utf16_bom?(obj)
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utf16_to_utf8(obj)
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else
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pdfdoc_to_utf8(obj)
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end
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else
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obj
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end
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end
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def has_utf16_bom?(str)
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first_bytes = str[0,2]
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return false if first_bytes.nil?
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first_bytes.unpack("C*") == [254, 255]
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end
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# TODO find a PDF I can use to spec this behaviour
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#
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def pdfdoc_to_utf8(obj)
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obj.force_encoding("utf-8")
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obj
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end
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# one day we'll all run on a 1.9 compatible VM and I can just do this with
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# String#encode
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#
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def utf16_to_utf8(obj)
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str = obj[2, obj.size].to_s
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str = str.unpack("n*").pack("U*")
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str.force_encoding("utf-8")
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str
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end
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def root
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@root ||= @objects.deref_hash(@objects.trailer[:Root]) || {}
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end
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end
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end
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################################################################################
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require 'pdf/reader/resources'
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require 'pdf/reader/advanced_text_run_filter'
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require 'pdf/reader/buffer'
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require 'pdf/reader/bounding_rectangle_runs_filter'
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require 'pdf/reader/cid_widths'
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require 'pdf/reader/cmap'
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require 'pdf/reader/encoding'
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require 'pdf/reader/error'
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require 'pdf/reader/filter'
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require 'pdf/reader/filter/ascii85'
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require 'pdf/reader/filter/ascii_hex'
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require 'pdf/reader/filter/depredict'
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require 'pdf/reader/filter/flate'
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require 'pdf/reader/filter/lzw'
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require 'pdf/reader/filter/null'
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require 'pdf/reader/filter/run_length'
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require 'pdf/reader/font'
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require 'pdf/reader/font_descriptor'
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require 'pdf/reader/form_xobject'
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require 'pdf/reader/glyph_hash'
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require 'pdf/reader/lzw'
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require 'pdf/reader/object_cache'
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require 'pdf/reader/object_hash'
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require 'pdf/reader/object_stream'
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require 'pdf/reader/pages_strategy'
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require 'pdf/reader/parser'
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require 'pdf/reader/point'
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require 'pdf/reader/print_receiver'
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require 'pdf/reader/rectangle'
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require 'pdf/reader/reference'
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require 'pdf/reader/register_receiver'
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require 'pdf/reader/no_text_filter'
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require 'pdf/reader/null_security_handler'
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require 'pdf/reader/security_handler_factory'
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require 'pdf/reader/standard_key_builder'
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require 'pdf/reader/key_builder_v5'
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require 'pdf/reader/aes_v2_security_handler'
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require 'pdf/reader/aes_v3_security_handler'
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require 'pdf/reader/rc4_security_handler'
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require 'pdf/reader/unimplemented_security_handler'
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require 'pdf/reader/stream'
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require 'pdf/reader/text_run'
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require 'pdf/reader/type_check'
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require 'pdf/reader/page_state'
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require 'pdf/reader/page_text_receiver'
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require 'pdf/reader/token'
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require 'pdf/reader/xref'
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require 'pdf/reader/page'
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require 'pdf/reader/validating_receiver'
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