On Fri, Sep 24, 2010 at 1:13 AM, Robert Muir <rcm...@gmail.com> wrote:
> > but case-sensitive filenames (such as windows) don't use locale-dependent > comparisons? > they implement locale-independent case-folding. for example if i have a > file "σ.txt", I cannot create "ς.txt". (I just tried) > Both of these files are already in lowercase. > > The interesting question is: how does hashCode() relate? Because a hashcode > based upon String.toLowerCase(Locale.ENGLISH) would return different > hashcodes for these two filenames, but with UCharacter.foldCase(), it would > be the same. > i did more tests here against windows, and looking at the api link you provided: http://download.oracle.com/javase/6/docs/api/java/io/File.html#hashCode%28%29 <http://download.oracle.com/javase/6/docs/api/java/io/File.html#hashCode%28%29>windows appears to implement something closer to 'simple case folding': http://icu-project.org/apiref/icu4j/com/ibm/icu/lang/UCharacter.html#foldCase(int, boolean), not the 'full case folding'. For example I can create "ss.txt" and "ß.txt" windows also doesn't lowercase any supplementary characters. In other words, its case comparison acts exactly like String.equalsIgnoreCase(). So, for File.hashCode(), a hashcode computed with Character.toLowerCase(Character.toUpperCase(char)) would be completely consistent with its case sensitivity. -- Robert Muir rcm...@gmail.com
