Extracted control char sanitization to module level and applied to sh…

…ared strings table output.

Conflicts:
	lib/axlsx/workbook/shared_strings_table.rb

lib/axlsx.rb

@@ -127,6 +127,14 @@ def self.camel(s="", all_caps = true)
     s.gsub(/_(.)/){ $1.upcase }
   end
 
+    # returns the provided string with all invalid control charaters
+    # removed.
+    # @param [String] str The sting to process
+    # @return [String]
+    def self.sanitize(str)
+      str.gsub(CONTROL_CHAR_REGEX, '')
+    end
+
 
   # Instructs the serializer to not try to escape cell value input. 
   # This will give you a huge speed bonus, but if you content has <, > or other xml character data

lib/axlsx/workbook/shared_strings_table.rb

@@ -41,7 +41,8 @@ def initialize(cells)
     # @param [String] str
     # @return [String]
     def to_xml_string
-      '<?xml version="1.0" encoding="UTF-8"?><sst xmlns="' << XML_NS << '" count="' << @count.to_s << '" uniqueCount="' << unique_count.to_s << '">' << @shared_xml_string << '</sst>'
+      str = '<?xml version="1.0" encoding="UTF-8"?><sst xmlns="' << XML_NS << '" count="' << @count.to_s << '" uniqueCount="' << unique_count.to_s << '">' << @shared_xml_string << '</sst>'
+      str = Axlsx::sanitize(str)
     end
 
     private

lib/axlsx/workbook/worksheet/worksheet.rb

@@ -542,15 +542,7 @@ def to_xml_string
         item.to_xml_string(str) if item
       end
       str << '</worksheet>'
-      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, '')
+      Axlsx::sanitize(str)
     end
 
     # The worksheet relationships. This is managed automatically by the worksheet