Ian Rogers wrote:
Hi,
please give your comments on the attached patch. It tries to reduce the
size of char[] for strings used to hold numbers. It changes Float/Double
equals to use bit based comparisons rather than division. It increases
the use of valueOf methods. It adds a cache of values from -128 to 127
for Long. It adds a cache of the values of zero and one to Float and
Double.
The string size is an estimate. For decimal numbers it will divide the
value repeatedly by 8, causing the string length to be over estimated by
a character for values like 999. This string size is still better than
the current estimate of 33 characters. It also avoids the use of
division (shifts are used) and/or lookup tables.
I would like to know your motivation for doing this. Do you have any
evidence that this will reduce memory usage and speed up real applications?
That said, in our gcj-3.4 based application, we had to create a cache of
Integers because we were creating large numbers of them all with a small
set of values.
So in principle this could be a good approach, but I don't know if we
can assume that there is universal benefit from a patch like this. Can
you point to any benchmarks where this helps?
Thanks,
David Daney
