fixed regular expression generation for removing control characters.

2 files changed, 94 insertions, 13 deletions

diff --git a/lib/axlsx/util/constants.rb b/lib/axlsx/util/constants.rb
index a83f76e6..b1139133 100644
--- a/lib/axlsx/util/constants.rb
+++ b/lib/axlsx/util/constants.rb
@@ -1,4 +1,3 @@
-# encoding: UTF-8
 module Axlsx
 
   # XML Encoding
@@ -129,7 +128,7 @@ module Axlsx
 
   # digital signature origin content type
   DIGITAL_SIGNATURE_ORIGIN_CT = "application/vnd.openxmlformats-package.digital-signature-origin"
-  
+
   # digital signature certificate content type
   DIGITAL_SIGNATURE_CERTIFICATE_CT = "application/vnd.openxmlformats-package.digital-signature-certificate"
 
@@ -151,7 +150,7 @@ module Axlsx
   #drawing content type
   DRAWING_CT = "application/vnd.openxmlformats-officedocument.drawing+xml"
 
-  
+
   # xml content type extensions
   XML_EX = "xml"
 
@@ -287,4 +286,85 @@ module Axlsx
 
   # error message for non 'integerish' value
   ERR_INTEGERISH = "You value must be, or be castable via to_i, an Integer. You provided %s"
+
+  # Regex to match forbidden control characters
+  # The following will be automatically stripped from worksheets.
+  #
+  # x00 Null
+  # x01 Start Of Heading
+  # x02 Start Of Text
+  # x03End Of Text
+  # x04 End Of Transmission
+  # x05 Enquiry
+  # x06 Acknowledge
+  # x07 Bell
+  # x08 Backspace
+  # x0B Line Tabulation
+  # x0C Form Feed
+  # x0E Shift Out
+  # x0F Shift In
+  # x10 Data Link Escape
+  # x11 Device Control One
+  # x12 Device Control Two
+  # x13 Device Control Three
+  # x14 Device Control Four
+  # x15 Negative Acknowledge
+  # x16 Synchronous Idle
+  # x17 End Of Transmission Block
+  # x18 Cancel
+  # x19 End Of Medium
+  # x1A Substitute
+  # x1B Escape
+  # x1C Information Separator Four
+  # x1D Information Separator Three
+  # x1E Information Separator Two
+  # x1F Information Separator One
+  #
+  # The following are not dealt with. 
+  # If you have this in your data, expect excel to blow up!
+  #
+  # x7F	Delete
+  # x80	Control 0080
+  # x81	Control 0081
+  # x82	Break Permitted Here
+  # x83	No Break Here
+  # x84	Control 0084
+  # x85	Next Line (Nel)
+  # x86	Start Of Selected Area
+  # x87	End Of Selected Area
+  # x88	Character Tabulation Set
+  # x89	Character Tabulation With Justification
+  # x8A	Line Tabulation Set
+  # x8B	Partial Line Forward
+  # x8C	Partial Line Backward
+  # x8D	Reverse Line Feed
+  # x8E	Single Shift Two
+  # x8F	Single Shift Three
+  # x90	Device Control String
+  # x91	Private Use One
+  # x92	Private Use Two
+  # x93	Set Transmit State
+  # x94	Cancel Character
+  # x95	Message Waiting
+  # x96	Start Of Guarded Area
+  # x97	End Of Guarded Area
+  # x98	Start Of String
+  # x99	Control 0099
+  # x9A	Single Character Introducer
+  # x9B	Control Sequence Introducer
+  # x9C	String Terminator
+  # x9D	Operating System Command
+  # x9E	Privacy Message
+  # x9F	Application Program Command
+  #
+  # The following are allowed:
+  #
+  # x0A Line Feed (Lf)
+  # x0D Carriage Return (Cr)
+  # x09 Character Tabulation
+  # @see http://www.codetable.net/asciikeycodes
+  pattern = "[\x0-\x08\x0B\x0C\x0E-\x1F]"
+  pattern= pattern.respond_to?(:encode) ? pattern.encode('UTF-8') : pattern
+  CONTROL_CHAR_REGEX = Regexp.new(pattern, 'n')
+
 end
diff --git a/lib/axlsx/workbook/worksheet/worksheet.rb b/lib/axlsx/workbook/worksheet/worksheet.rb
index 6c190470..30d5c09c 100644
--- a/lib/axlsx/workbook/worksheet/worksheet.rb
+++ b/lib/axlsx/workbook/worksheet/worksheet.rb
@@ -494,23 +494,24 @@ module Axlsx
     # This intentionally does not use nokogiri for performance reasons
     # @return [String]
     def to_xml_string
-      auto_filter.apply
+      auto_filter.apply if auto_filter.range
       str = '<?xml version="1.0" encoding="UTF-8"?>'
       str << worksheet_node
       serializable_parts.each do |item|
         item.to_xml_string(str) if item
       end
       str << '</worksheet>'
-
-      if RUBY_VERSION == "1.8.7"
-        nasty_control_char_matcher = Regexp.new("[\x01\x02\x03\x04\x05\x06\x07\x08\x1F\v\xE2]")
-      else
-        nasty_control_char_matcher = Regexp.new("[\x01\x02\x03\x04\x05\x06\x07\x08\x1F\v\u2028]")
-      end
-
-      str.gsub(nasty_control_char_matcher,'')
+      sanitize(str)
     end
 
+    # returns the provided string with all invalid control charaters
+    # removed.
+    # @param [String] str The sting to process
+    # @return [String]
+    def sanitize(str)
+      str.gsub(CONTROL_CHAR_REGEX, '')
+    end
+    
     # The worksheet relationships. This is managed automatically by the worksheet
     # @return [Relationships]
     def relationships
@@ -567,7 +568,7 @@ module Axlsx
 
 
     private
-
+   
     def validate_sheet_name(name)
       DataTypeValidator.validate "Worksheet.name", String, name
       raise ArgumentError, (ERR_SHEET_NAME_TOO_LONG % name) if name.size > 31