More efficient _OneByteString.toLowerCase().

More efficient _OneByteString.toLowerCase().

[Lasse Reichstein Nielsen, 2014-03-25 16:35:37]

https://codereview.chromium.org/211283003/diff/1/runtime/lib/string_patch.dart
File runtime/lib/string_patch.dart (right):

https://codereview.chromium.org/211283003/diff/1/runtime/lib/string_patch.dar...
runtime/lib/string_patch.dart:810: 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe,
0xff,
ff -> df

[srdjan, 2014-03-25 17:33:16]

This looks faster, is it visible in any of the benchmarks that we are tracking?

https://codereview.chromium.org/211283003/diff/1/runtime/lib/string_patch.dart
File runtime/lib/string_patch.dart (right):

https://codereview.chromium.org/211283003/diff/1/runtime/lib/string_patch.dar...
runtime/lib/string_patch.dart:818: upperCaseDetected: {
Using label and breaks here looks gross, IMO. Why not use a separate function
instead: 'isAllLowerCase' or similar.

[Lasse Reichstein Nielsen, 2014-03-25 19:04:27]

Haven't run anything but my own micro-benchmark yet.
I'd compare it to Anders' version tomorrow, and I have a couple of table-less
variants too.

https://codereview.chromium.org/211283003/diff/1/runtime/lib/string_patch.dart
File runtime/lib/string_patch.dart (right):

https://codereview.chromium.org/211283003/diff/1/runtime/lib/string_patch.dar...
runtime/lib/string_patch.dart:818: upperCaseDetected: {
Just me microoptimizing. 
On the test I used, it gave another few procent of improvement to do it this way
instead of calling a "_toLowerCaseConvert()" function.

[sra1, 2014-03-25 19:07:14]

https://codereview.chromium.org/211283003/diff/1/runtime/lib/string_patch.dart
File runtime/lib/string_patch.dart (right):

https://codereview.chromium.org/211283003/diff/1/runtime/lib/string_patch.dar...
runtime/lib/string_patch.dart:833: return result;
Are single character strings canonicalized (like in V8)?
If so,
   if (this.length == 1) return result[0];

I can't tell if line 233 is for canonicalization or due to a belief that using
substring with length 1 is common.