On 7/17/15 1:04 AM, Peter Levart wrote:
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 ?
Yes, dos timestamp has a 2107 ceiling, given it's 32-bit nature, like
the unix time has a 2038 ceiling if
the long stays as 32-bit.
- depending on the above answers, should there be a DOSTIME_AFTER_2107
in addition to DOSTIME_BEFORE_1980 to which the date is clamped?
If ZIP is still being used on 2107, "we" have a problem.
-Sherman
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
