Improve split #138
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Codecov Report
@@ Coverage Diff @@
## master #138 +/- ##
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- Coverage 89.23% 89.20% -0.03%
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Files 19 19
Lines 3027 3029 +2
Branches 609 612 +3
==========================================
+ Hits 2701 2702 +1
Misses 187 187
- Partials 139 140 +1
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Fixes google#131. This change modifies Pattern.split to omit a leading empty match. This behavior was specified in JDK8 and brings RE2/J split into line with more recent JDK implementations. Furthermore, the split function no longer needs determine the number of matches before assembling the result. The upshot is that the number of find() calls is halved in many cases. The benchmark in the previous change shows a significant improvement. Reference impl (JDK): BenchmarkSplit.benchmarkSplit JDK avgt 5 14.217 ± 0.410 us/op RE2J (before): BenchmarkSplit.benchmarkSplit RE2J avgt 5 95.807 ± 6.737 us/op RE2J (after): BenchmarkSplit.benchmarkSplit RE2J avgt 5 49.092 ± 0.717 us/op
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Omit leading empty matches from Pattern.split, improve performance
Fixes #131.
This change modifies Pattern.split to omit a leading empty match. This
behavior was specified in JDK8 and brings RE2/J split into line with
more recent JDK implementations.
Furthermore, the split function no longer needs determine the number of
matches before assembling the result. The upshot is that the number of
find() calls is halved in many cases. The benchmark in the previous
change shows a significant improvement.