My own diff project, plus Neil Fraser's diff-match-patch in C# split into classes

For Neil's project, see http://code.google.com/p/google-diff-match-patch/

A file difference/comparison class. Performs much the same function as the Diff programs used in version control. Compares two strings in chunks as determined by a Regex splitter.

Output from the class in as an Enumerator. It is more suited to visual display than change analysis.

The active ingredient is [/Code/Diff.cs] in the [System.Text] namespace.

The tools in [DiffCode.cs] can be used to analyse differences, and store/retrieve various revisions of files. The Decode/Encode methods have variants which are suitable for data transmission and database storage.

Regex splitters omit the matched parts unless they are in capturing groups. See that the examples in Default.aspx.cs (from the static 'Diff') are all in capturing groups.

• unit tests around DocDiff

• improve memory thrash in the cases of search-and-replace differences and delete-and-rewrite differences by deferring string splitting until after differences are computed (should be able to work with indexes alone and post-process the actual edits afterwards)

• Include some of the divide-and-conquer and early group rejection from DMP.