Files created in Excel for Macintosh, by default, save workbooks with all date cell values using 1904 date windowing. HSSFDateUtil assumes 1900 windowing, thus converts these dates incorrectly. Patch includes changes to Workbook.java, HSSFCell.java, and HSSFDateUtil.java to correctly identify whether 1900 or 1904 windowing is being used and do the correct conversion. Also adds some additional internal date formats to HSSFDateUtil.isInternalDateFormat(int).
Created attachment 3769 [details] Handle both 1900 and 1904 date windowing - patches to Workbook, HSSFCell, and HSSFDateUtil
Done, applied. You know if we had a unit test for it, then we might not break it later.. (So far just about EVERY thing that doesn't have a unit test has been broken from time to time...the unit tested code has stayed clean!)
Reverted the internal date format addition, since they caused 24125. Tho only 0xaa and 0xac have been reported incorrect, have reverted the whole set (0xa4 to 0xad) since we cant now say which ones are suspect!
even a7-ab has been reported to be percentage formats.. so best to keep the whole set out.