Support customizable sort mode

[Francois Ferrand]

Add support case sensitive, case insensitive and natural sort modes.
The mode is used in file list view as well as directory list view.

The patch also includes the UI and settings changes and unit tests.

[Tim Kosse]

A couple of issues, ordered by severity:

• Natural sort doesn't seem natural at all. Why is 25 < 021? I suggest ​http://sourcefrog.net/projects/natsort/ adapted for use with wx.

• Windows is case-sensitive, other platforms are case-insensitive. Hence the default value of the option should reflect the case-sensitivity of the operating system.

• You're using Toupper, whereas wx' CmpNoCase uses Tolower. To make things symmetric, please use Tolower as well. Otherwise strings without numbers might be sorted differently in natural sort than in case-insensitive sort, leading to confusion.

• wxChar may be defined as wchar_t, signedness of wchar_t is unspecified by the C(++) standard. Before taking the difference of the two chars, cast them both to a signed type of sufficient size (e.g. int)

Could you please address these issues?

[Francois Ferrand]

patch v2

[Francois Ferrand]

Natural sort from ​http://sourcefrog.net/projects/natsort/ has some strange behavior as well: it produces 010 < 02, as part of its behavior of not ignoring leading zeros, which tends to give more reasonable results on decimal fractions (e.g. it produces 0.010 < 0.02).

Ignoring fractions seems more reasonable for file names, since we probably do not have fractions in file names, except for version numbers which should be sorted 'normally'.

Thus I just fixed my earlier implementation, to fix the 25 < 021 issue, and added the test cases from ​http://sourcefrog.net/projects/natsort/, except for the two cases '1.010' < '02' and '1.02' < '1.1' (which would break '010' > '02' and '02' > '1', respectively).

Other issues taken into account as well.

[Tim Kosse]

Version numbers usually don't have leading zeroes in each segment. FileZilla 3.008.001 would just be bizarre ;)

Two issues still:

The choice on some platforms still has the wrong item sufficed with " (default)". I'd solve it using platform attributes in the XRC file: ​http://docs.wxwidgets.org/trunk/overview_xrcformat.html#overview_xrcformat_platform

Inconsistent indentation in the patch. FileZilla uses tabs for indentation.

[Francois Ferrand]

Should be OK now.

[Tim Kosse]

Thanks, I've applied and committed your patch. Keep up the good work.

[Tim Kosse]

Small follow-up: I've refactored the sorting code to greatly reduce code duplication.