Hi Andrey, This is best discussed in the core-libs mailing list.
Cheers, Martijn On 26 April 2016 at 10:49, Andrey <and...@tweak.su> wrote: > Hello! > > I read source code equalsIgnoreCase(...) in String class and saw that it > is not optimal. This method check length and call > regionMatches(...) with 'constant' values > > > http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/java/lang/String.java#l1095 > > > ... > > && (anotherString.value.length == value.length) > && regionMatches(true, 0, anotherString, 0, value.length); > ... > > But regionMatches(...) check 'constant' values > > > http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/java/lang/String.java#l1338 > > // Note: toffset, ooffset, or len might be near -1>>>1. > if ((ooffset < 0) || (toffset < 0) > || (toffset > (long)value.length - len) > || (ooffset > (long)other.value.length - len)) { > return false; > } > > and increment equalent variables to==po in loop > > > http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/java/lang/String.java#l1344 > > while (len-- > 0) { > > char c1 = ta[to++]; > > char c2 = pa[po++]; > > ... > > } > > and use if(...) in while loop > > > http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/java/lang/String.java#l1349 > > if (ignoreCase) { > > ... > > } > > > > May be can create optimized regionMatches(...) for use > in equalsIgnoreCase(...)? >
