Hi Sherman, On 07/15/2015 09:10 PM, Xueming Shen wrote:
Hi,
Please help review the change for JDK-8130914.
issue: https://bugs.openjdk.java.net/browse/JDK-8130914 webrev: http://cr.openjdk.java.net/~sherman/8130914/
This is a "regression" triggered by https://bugs.openjdk.java.net/browse/JDK-8130914 http://cr.openjdk.java.net/~redestad/jdk9/8073497/webrev.6/
And-ing the result with a 32 bit mask (2^32 - 1) does make sure that high 32 bits are not touched by year encoding. As I understand, this starts to be a problem with year 2044 and beyond when (year - 1980) << 25 becomes a negative number. Expanding it to long sets the high 32 bits too. If we treat the lower 32 bits as unsigned, we accommodate for years up to and including 2107. At 2108, the overflow happens and decoding the year back gives 1980 instead of 2108. So I wonder: - will there be a DOS compatible ZIP format after 2108 ? - will there be Java after 2108 ? - depending on the above answers, should there be a DOSTIME_AFTER_2107 in addition to DOSTIME_BEFORE_1980 to which the date is clamped? Regards, Peter
In which the change is to utilize a high 32-bit of the time value to store < 2000 ms time piece. It appears the offending timestamp (year 2067...) triggers the 32-bit "overflow" when converting java time to a 32-bit dos time.
Thanks, -Sherman