@cl4es made performance optimizations for the simple specifiers of String.format in PR https://github.com/openjdk/jdk/pull/2830. Based on the same idea, I continued to make improvements. I made patterns like %2d %02d also be optimized.
The following are the test results based on MacBookPro M1 Pro: -Benchmark Mode Cnt Score Error Units -StringFormat.complexFormat avgt 15 1862.233 ? 217.479 ns/op -StringFormat.int02Format avgt 15 312.491 ? 26.021 ns/op -StringFormat.intFormat avgt 15 84.432 ? 4.145 ns/op -StringFormat.longFormat avgt 15 87.330 ? 6.111 ns/op -StringFormat.stringFormat avgt 15 63.985 ? 11.366 ns/op -StringFormat.stringIntFormat avgt 15 87.422 ? 0.147 ns/op -StringFormat.widthStringFormat avgt 15 250.740 ? 32.639 ns/op -StringFormat.widthStringIntFormat avgt 15 312.474 ? 16.309 ns/op +Benchmark Mode Cnt Score Error Units +StringFormat.complexFormat avgt 15 740.626 ? 66.671 ns/op (+151.45) +StringFormat.int02Format avgt 15 131.049 ? 0.432 ns/op (+138.46) +StringFormat.intFormat avgt 15 67.229 ? 4.155 ns/op (+25.59) +StringFormat.longFormat avgt 15 66.444 ? 0.614 ns/op (+31.44) +StringFormat.stringFormat avgt 15 62.619 ? 4.652 ns/op (+2.19) +StringFormat.stringIntFormat avgt 15 89.606 ? 13.966 ns/op (-2.44) +StringFormat.widthStringFormat avgt 15 52.462 ? 15.649 ns/op (+377.95) +StringFormat.widthStringIntFormat avgt 15 101.814 ? 3.147 ns/op (+206.91) ------------- Commit messages: - move testcases to Basic.java - move testcase from BasicInt to Basic-X - add copyright info - Improve the readability, suggestion from @rgiulietti - Improve the readability of parseArgument, suggestion from @rgiulietti - Fix from @rgiulietti review - Refactor according to rgiulietti's suggestion and add testcases - fix : the exception thrown when the input does not include conversion is different from baselne. - code format - refactor for review & remove comment - ... and 25 more: https://git.openjdk.org/jdk/compare/a2391a92...bce554a8 Changes: https://git.openjdk.org/jdk/pull/15776/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15776&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8316704 Stats: 248 lines in 4 files changed: 212 ins; 14 del; 22 mod Patch: https://git.openjdk.org/jdk/pull/15776.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/15776/head:pull/15776 PR: https://git.openjdk.org/jdk/pull/15776
