On Wed, 27 Sep 2023 19:13:02 GMT, 温绍锦 <d...@openjdk.org> wrote:
>> @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) > > 温绍锦 has updated the pull request incrementally with one additional commit > since the last revision: > > fix : the exception thrown when the input does not include conversion is > different from baselne. You might consider this alternative, which IMO is simpler and more readable. int parse() { // %[argument_index$][flags][width][.precision][t]conversion // %(\d+$)?([-#+ 0,(<]*)?(\d+)?(.\d+)?([tT])?([a-zA-Z%]) parseArgument(); parseFlag(); parseWidth(); int precisionSize = parsePrecision(); if (precisionSize < 0) { return 0; } // ([tT])?([a-zA-Z%]) char t = '\0', conversion = '\0'; if ((c == 't' || c == 'T') && off + 1 < max) { char c1 = s.charAt(off + 1); if (isConversion(c1)) { t = c; conversion = c1; off += 2; } } if (conversion == '\0' && isConversion(c)) { conversion = c; ++off; } if (argSize + flagSize + widthSize + precisionSize + t + conversion != 0) { if (al != null) { FormatSpecifier formatSpecifier = new FormatSpecifier(s, start, argSize, flagSize, widthSize, precisionSize, t, conversion); al.add(formatSpecifier); } return off - start; } return 0; } private void parseArgument() { // (\d+$)? int i = off; for (; i < max && isDigit(c = s.charAt(i)); ++i); // empty body if (i == max || c != '$') { c = first; return; } ++i; // skip '$' if (i < max) { c = s.charAt(i); } argSize = i - off; off = i; } private void parseFlag() { // ([-#+ 0,(<]*)? int i = off; for (; i < max && Flags.isFlag(c = s.charAt(i)); ++i); // empty body flagSize = i - off; off = i; } private void parseWidth() { // (\d+)? int i = off; for (; i < max && isDigit(c = s.charAt(i)); ++i); // empty body widthSize = i - off; off = i; } private int parsePrecision() { // (.\d+)? if (c != '.') { return 0; } int i = off + 1; for (; i < max && isDigit(c = s.charAt(i)); ++i); // empty body if (i == off + 1) { // a '.' but no digits return -1; } int size = i - off; off = i; return size; } ------------- PR Comment: https://git.openjdk.org/jdk/pull/15776#issuecomment-1737986458
