Implement a tryParseSmi function in Dart for quick and frequent parsing of Smis.

Implement a tryParseSmi function in Dart for quick and frequent parsing of Smis.

Committed: https://code.google.com/p/dart/source/detail?r=22041

[siva, 2013-04-24 23:59:00]

https://codereview.chromium.org/14484003/diff/1/runtime/lib/integers_patch.dart
File runtime/lib/integers_patch.dart (right):

https://codereview.chromium.org/14484003/diff/1/runtime/lib/integers_patch.da...
runtime/lib/integers_patch.dart:28: while (ix > endIx) {
This check seems inverted here, did you mean
while (endIx > Ix)

https://codereview.chromium.org/14484003/diff/1/runtime/lib/integers_patch.da...
runtime/lib/integers_patch.dart:31: }
Why not use trim() here to remove the leading and trailing white spaces.
var trimmed_str = str.trim();
var ix = 0;
var endIx = trimmed_str.length - 1;

https://codereview.chromium.org/14484003/diff/1/runtime/lib/integers_patch.da...
runtime/lib/integers_patch.dart:47: int result = 0;
var result = 0; ?

Here and above for IsNegative as well.

[srdjan, 2013-04-25 17:30:07]

https://codereview.chromium.org/14484003/diff/1/runtime/lib/integers_patch.dart
File runtime/lib/integers_patch.dart (right):

https://codereview.chromium.org/14484003/diff/1/runtime/lib/integers_patch.da...
runtime/lib/integers_patch.dart:28: while (ix > endIx) {
On 2013/04/24 23:59:00, siva wrote:
> This check seems inverted here, did you mean
> while (endIx > Ix)

Yes, thanks.

https://codereview.chromium.org/14484003/diff/1/runtime/lib/integers_patch.da...
runtime/lib/integers_patch.dart:31: }
On 2013/04/24 23:59:00, siva wrote:
> Why not use trim() here to remove the leading and trailing white spaces.
> var trimmed_str = str.trim();
> var ix = 0;
> var endIx = trimmed_str.length - 1;

trim creates a new String if needed. This leads to a slow down of >30% . It is
slightly slower if no trim returns the original string (when not trimming is
needed).

[srdjan, 2013-04-25 17:30:25]

Committed patchset #2 manually as r22041 (presubmit successful).