improve handling of empty PDF Names

* '/' is a valid PDF name, we really don't want to throw a
  MalformedPDFError

lib/pdf/reader/buffer.rb

@@ -314,7 +314,7 @@ def prepare_regular_token
           @tokens << chr
           tok = ""
           break
-        when "\x28", "\x5B", "\x7B", "\x2F"
+        when "\x28", "\x5B", "\x7B"
           # opening delimiter, start of new token
           @tokens << tok if tok.size > 0
           @tokens << chr
@@ -326,6 +326,14 @@ def prepare_regular_token
           @tokens << chr
           tok = ""
           break
+        when "\x2F"
+          # PDF name, start of new token
+          @tokens << tok if tok.size > 0
+          @tokens << chr
+          next_char = peek_char
+          @tokens << "" if chr == "/" && (next_char == " " || next_char.nil?)
+          tok = ""
+          break
         else
           tok << chr
         end

lib/pdf/reader/parser.rb

@@ -130,6 +130,7 @@ def dictionary
     # reads a PDF name from the buffer and converts it to a Ruby Symbol
     def pdf_name
       tok = @buffer.token
+      tok = " " if tok == "" && RUBY_VERSION < "1.9"
       tok.gsub!(/#([A-Fa-f0-9]{2})/) do |match|
         match[1, 2].hex.chr
       end

spec/buffer_spec.rb

@@ -89,6 +89,16 @@
     buf.token.should be_nil
   end
 
+  it "should correctly return two empty name tokens" do
+    buf = parse_string("/ /")
+
+    buf.token.should eql("/")
+    buf.token.should eql("")
+    buf.token.should eql("/")
+    buf.token.should eql("")
+    buf.token.should be_nil
+  end
+
   it "should tokenise a dict correctly" do
     buf = parse_string("/Registry (Adobe) /Ordering (Japan1) /Supplement")
     buf.token.should eql("/")

spec/parser_spec.rb

@@ -19,11 +19,31 @@
     parse_string("/Ja#6des").parse_token.should eql(:"James")
   end
 
-  # '/' is a valid PDF name, but :"" is not a valid ruby symbol.
-  # How should I handle this?
-  it "should parse an empty name correctly" #do
-    #parse_string("/").parse_token.should eql(:"")
-  #end
+  # '/' is a valid PDF name, but :"" is only a valid ruby symbol in 1.9
+  # On 1.8 VMs the best I can do is a string with a single space. This
+  # is bound to cause trouble but it's better than treating empty PDF
+  # Names as a syntax error
+  if RUBY_VERSION >= "1.9"
+    it "should parse an empty name correctly" do
+      parse_string("/").parse_token.should eql(:"")
+    end
+
+    it "should parse two empty names correctly" do
+      parser = parse_string("/ /")
+      parser.parse_token.should eql(:"")
+      parser.parse_token.should eql(:"")
+    end
+  else
+    it "should parse an empty name correctly" do
+      parse_string("/").parse_token.should eql(:" ")
+    end
+
+    it "should parse two empty names correctly" do
+      parser = parse_string("/ /")
+      parser.parse_token.should eql(:" ")
+      parser.parse_token.should eql(:" ")
+    end
+  end
 
   it "should parse booleans correctly" do
     parse_string("true").parse_token.should be_true