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Posted to dev@xalan.apache.org by "Brian Minchau (JIRA)" <xa...@xml.apache.org> on 2005/03/09 22:16:00 UTC
[jira] Updated: (XALANJ-2077) Serializer's Encodings class methods slow: gettLastPrintable() convertJava2MimeEncoding()
[ http://issues.apache.org/jira/browse/XALANJ-2077?page=history ]
Brian Minchau updated XALANJ-2077:
----------------------------------
Component: Serialization
The expected perfomance gain from this modification is expected to be greatest for the serialization of small documents. This fix is expected to speed up the serialization stage by about 3% for small documents.
> Serializer's Encodings class methods slow: gettLastPrintable() convertJava2MimeEncoding()
> -----------------------------------------------------------------------------------------
>
> Key: XALANJ-2077
> URL: http://issues.apache.org/jira/browse/XALANJ-2077
> Project: XalanJ2
> Type: Improvement
> Components: Serialization
> Reporter: Brian Minchau
> Priority: Minor
>
> The serializer's methods:
> org.apache.xml.serializer.Encodings.getLastPrintable(String encoding)
> org.apache.xml.serializer.Encodings.convertJava2MimeEncoding(String encoding)
> are both slower than they need to be.
> For some reason the java.lang.String.toUpperCase() methods used in each of
> these seems to be quite slow.
> Code like this seems to run twice as fast as calling String.toUpperCase():
> static private String toUpperCaseFast(final String s) {
> boolean different = false;
> final int mx = s.length();
> char[] chars = new char[mx];
> for (int i=0; i < mx; i++) {
> char ch = s.charAt(i);
> if (Character.isLowerCase(ch)) {
> ch = Character.toUpperCase(ch);
> different = true; // the uppercased String is different
> }
> chars[i] = ch;
> }
>
> // A little optimization, don't call sb.toString() if
> // the uppercased string is the same as the input string.
> final String upper;
> if (different)
> upper = chars.toString();
> else
> upper = s;
>
> return upper;
> }
> --------------------------------
> Perhaps the official toUpperCase() method is Locale sensitive, although it doesn't need
> to be because the encoding supported are IANA-CHARSETS
> (Internet Assigned Numbers Authority) Official Names for Character Sets, ed. Keld Simonsen et al. (See http://www.iana.org/assignments/character-sets.)
> These names are from the character set of pritable US-ASCII characters, so perhaps even the methods called in the method above, Character.isLowerCase(ch) and Character.toUpperCase(ch) can be converted into faster bit manimpulation.
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