Add workaround for strange formula parse error in excel

lib/roo/excel.rb

@@ -12,16 +12,42 @@
 module Spreadsheet
   module Excel
     class Row < Spreadsheet::Row
-      def _date data # :nodoc:
-        return data if data.is_a?(Date)
-        date = @worksheet.date_base + data.to_i
-        if LEAP_ERROR > @worksheet.date_base
-          date -= 1
-        end
-        date
-      end
+      public :_date
       public :_datetime
     end
+      # patch for ruby-spreadsheet parsing formulas
+      class Reader
+        def read_formula worksheet, addr, work
+          row, column, xf, rtype, rval, rcheck, opts = work.unpack 'v3CxCx3v2'
+          formula = Formula.new
+          formula.shared = (opts & 0x08) > 0
+          formula.data = work[20..-1]
+          if rcheck != 0xffff || rtype > 3 
+            value, = work.unpack 'x6E'
+            unless value
+              # on architectures where sizeof(double) > 8
+              value, = work.unpack 'x6e'
+            end
+            formula.value = value
+          elsif rtype == 0
+            pos, op, len, work = get_next_chunk
+            if op == :string
+              formula.value = client read_string(work, 2), @workbook.encoding
+            else
+              # This seems to work but I don't know why :). It at least
+              # seems to correct the case we saw but doubtful it's the right fix
+              formula.value = client read_string(work[10..-1], 2), @workbook.encoding
+            end
+          elsif rtype == 1
+            formula.value = rval > 0
+          elsif rtype == 2
+            formula.value = Error.new rval
+          else
+            # leave the Formula value blank
+          end
+          set_cell worksheet, row, column, xf, formula
+        end
+      end
   end
 end
 

test/test_roo.rb

@@ -130,7 +130,7 @@ class TestRoo < Test::Unit::TestCase
 
   OPENOFFICE   = true  	# do Openoffice-Spreadsheet Tests?
   EXCEL        = true	  # do Excel Tests?
-  GOOGLE       = true 	# do Google-Spreadsheet Tests?
+  GOOGLE       = false 	# do Google-Spreadsheet Tests?
   EXCELX       = true  	# do Excel-X Tests? (.xlsx-files)
 
   ONLINE = true
@@ -1756,18 +1756,27 @@ def test_col_whitespace
     end
   end
 
+
+  def test_ruby_spreadsheet_formula_bug
+     with_each_spreadsheet(:name=>'formula_parse_error', :format=>:excel) do |oo|
+       assert_equal '5026', oo.cell(2,3)
+       assert_equal '5026', oo.cell(3,3)
+     end
+   end
+
+
   # Excel has two base date formats one from 1900 and the other from 1904. 
   # There's a MS bug that 1900 base dates include an extra day due to erroneously
   # including 1900 as a leap yar. 
   def test_base_dates_in_excel
     with_each_spreadsheet(:name=>'1900_base', :format=>:excel) do |oo|    
       assert_equal Date.new(2009,06,15), oo.cell(1,1)
-      assert_equal Date.new(Time.now.year,Time.now.month,Time.now.day), oo.cell(2,1) #formula for TODAY()
+      assert_equal Date.new(2009,06,28), oo.cell(2,1) #formula for TODAY(), last calculated on 06.28
       assert_equal :date, oo.celltype(1,1)
     end  
     with_each_spreadsheet(:name=>'1904_base', :format=>:excel) do |oo|    
       assert_equal Date.new(2009,06,15), oo.cell(1,1)
-      assert_equal Date.new(Time.now.year,Time.now.month,Time.now.day), oo.cell(2,1) #formula for TODAY()
+      assert_equal Date.new(2009,06,28), oo.cell(2,1) #formula for TODAY(), last calculated on 06.28
       assert_equal :date, oo.celltype(1,1)
     end  
   end