NAITOH Jun e61bb75a86 [ruby/strscan] [JRuby] Optimize `scan()`: Remove duplicate `if ... (restLen() < patternsize()) return context.nil;` checks in `!headonly`. (https://github.com/ruby/strscan/pull/110) - before: #109 ## Why? d31274f41b/ext/jruby/org/jruby/ext/strscan/RubyStringScanner.java (L371-L373) This means the following : `if (str.size() - curr < pattern.size()) return context.nil;` A similar check is made within `StringSupport#index()` within `!headonly`. be7815ec02/core/src/main/java/org/jruby/util/StringSupport.java (L1706-L1720) ```Java public static int index(ByteList source, ByteList other, int offset, Encoding enc) { int sourceLen = source.realSize(); int sourceBegin = source.begin(); int otherLen = other.realSize(); if (otherLen == 0) return offset; if (sourceLen - offset < otherLen) return -1; ``` - source = `strBL` - other = `patternBL` - offset = `strBeg + curr` This means the following : `if (strBL.realSize() - (strBeg + curr) < patternBL.realSize()) return -1;` Both checks are the same. ## Benchmark It shows String as a pattern is 2.40x faster than Regexp as a pattern. ``` $ benchmark-driver benchmark/check_until.yaml Warming up -------------------------------------- regexp 7.613M i/s - 7.593M times in 0.997350s (131.35ns/i) regexp_var 7.793M i/s - 7.772M times in 0.997364s (128.32ns/i) string 13.222M i/s - 13.199M times in 0.998297s (75.63ns/i) string_var 15.283M i/s - 15.216M times in 0.995667s (65.43ns/i) Calculating ------------------------------------- regexp 10.003M i/s - 22.840M times in 2.283361s (99.97ns/i) regexp_var 9.991M i/s - 23.378M times in 2.340019s (100.09ns/i) string 23.454M i/s - 39.666M times in 1.691221s (42.64ns/i) string_var 23.998M i/s - 45.848M times in 1.910447s (41.67ns/i) Comparison: string_var: 23998466.3 i/s string: 23453777.5 i/s - 1.02x slower regexp: 10002809.4 i/s - 2.40x slower regexp_var: 9990580.1 i/s - 2.40x slower ``` https://github.com/ruby/strscan/commit/843e931d13		2024-10-26 18:44:15 +09:00
..
test_ractor.rb	Merge strscan-3.0.5	2022-12-09 16:36:22 +09:00
test_stringscanner.rb	[ruby/strscan] [JRuby] Optimize `scan()`: Remove duplicate `if	2024-10-26 18:44:15 +09:00