class PDF::Reader::Parser
An internal PDF::Reader class that reads objects from the PDF file and converts them into useable ruby objects (hash's, arrays, true, false, etc)
Constants
- MAPPING
- STRATEGIES
- TOKEN_STRATEGY
Public Class Methods
Create a new parser around a PDF::Reader::Buffer object
buffer - a PDF::Reader::Buffer object that contains PDF data objects - a PDF::Reader::ObjectHash object that can return objects from the PDF file
# File lib/pdf/reader/parser.rb, line 62 def initialize(buffer, objects=nil) @buffer = buffer @objects = objects end
Public Instance Methods
Reads an entire PDF object from the buffer and returns it as a Ruby String. If the object is a content stream, returns both the stream and the dictionary that describes it
id - the object ID to return gen - the object revision number to return
# File lib/pdf/reader/parser.rb, line 95 def object(id, gen) Error.assert_equal(parse_token, id) Error.assert_equal(parse_token, gen) Error.str_assert(parse_token, "obj") obj = parse_token post_obj = parse_token if post_obj == "stream" stream(obj) else obj end end
Reads the next token from the underlying buffer and convets it to an appropriate object
operators - a hash of supported operators to read from the underlying buffer.
# File lib/pdf/reader/parser.rb, line 71 def parse_token(operators={}) token = @buffer.token if STRATEGIES.has_key? token STRATEGIES[token].call(self, token) elsif token.is_a? PDF::Reader::Reference token elsif operators.has_key? token Token.new(token) elsif token.respond_to?(:to_token) token.to_token elsif token =~ /\d*\.\d/ token.to_f else token.to_i end end
Private Instance Methods
reads a PDF array from the buffer and converts it to a Ruby Array.
# File lib/pdf/reader/parser.rb, line 141 def array a = [] loop do item = parse_token break if item.kind_of?(Token) and item == "]" raise MalformedPDFError, "unterminated array" if @buffer.empty? a << item end a end
reads a PDF dict from the buffer and converts it to a Ruby Hash.
# File lib/pdf/reader/parser.rb, line 114 def dictionary dict = {} loop do key = parse_token break if key.kind_of?(Token) and key == ">>" raise MalformedPDFError, "unterminated dict" if @buffer.empty? raise MalformedPDFError, "Dictionary key (#{key.inspect}) is not a name" unless key.kind_of?(Symbol) value = parse_token value.kind_of?(Token) and Error.str_assert_not(value, ">>") dict[key] = value end dict end
Reads a PDF hex string from the buffer and converts it to a Ruby String
# File lib/pdf/reader/parser.rb, line 155 def hex_string str = "".dup loop do token = @buffer.token break if token == ">" raise MalformedPDFError, "unterminated hex string" if @buffer.empty? str << token end # add a missing digit if required, as required by the spec str << "0" unless str.size % 2 == 0 str.scan(/../).map {|i| i.hex.chr}.join.force_encoding("binary") end
reads a PDF name from the buffer and converts it to a Ruby Symbol
# File lib/pdf/reader/parser.rb, line 132 def pdf_name tok = @buffer.token tok = tok.dup.gsub(/#([A-Fa-f0-9]{2})/) do |match| match[1, 2].hex.chr end tok.to_sym end
Decodes the contents of a PDF Stream and returns it as a Ruby String.
# File lib/pdf/reader/parser.rb, line 202 def stream(dict) raise MalformedPDFError, "PDF malformed, missing stream length" unless dict.has_key?(:Length) if @objects length = @objects.deref(dict[:Length]) else length = dict[:Length] || 0 end data = @buffer.read(length, :skip_eol => true) Error.str_assert(parse_token, "endstream") Error.str_assert(parse_token, "endobj") PDF::Reader::Stream.new(dict, data) end
Reads a PDF String from the buffer and converts it to a Ruby String
# File lib/pdf/reader/parser.rb, line 171 def string str = @buffer.token return "".dup.force_encoding("binary") if str == ")" Error.assert_equal(parse_token, ")") str.gsub!(/\\([nrtbf()\\\n]|\d{1,3})?|\r\n?|\n\r/m) do |match| MAPPING[match] || "".dup end str.force_encoding("binary") end