CODEWITHSUNDEEP
c++cdiffpatch
Matt Fichman
Matt Fichman

Reputation: 5696

Is there a way to diff files from C++?

I'm looking for a C or C++ diff library. I know I can use the Unix diff tool in combination with system or exec, but I really want a library. It would be handy if the library could perform patches as well, like the Unix patch tool.

Upvotes: 36

Views: 24385

Answers (6)

Matt Fichman
Matt Fichman

Reputation: 5696

I think I've found a good solution, finally:

The DTL - Diff Template Library --- Tutorial

It supports patch. I had to type "diff.cpp" into Google to find it. Hopefully it works!

Upvotes: 26

ptomato
ptomato

Reputation: 57870

Also pretty much unfindable in Google, it turns out that Gnulib has a diff module. This one seems sufficient for what I wanted a diff library for. It doesn't seem to have a patch module, though.

Upvotes: 1

Omnifarious
Omnifarious

Reputation: 56048

There is one that is part of Mercurial. It exists as some C code that's designed as a Python extension, but it could probably be extracted pretty easily. I believe it can also do binary diffs.

The relevant .c files are mercurial/bdiff.c, mercurial/mpatch.c and possibly mercurial/diffhelpers.c.

Upvotes: 3

Martin v. Löwis
Martin v. Löwis

Reputation: 127467

Subversion includes a library libsvn_diff.

Upvotes: 3

unwind
unwind

Reputation: 399833

This is an implementation of a "solution to SES/LCS with the Hirschberg linear space refinement as described in the following publication":

E. Myers, ``An O(ND) Difference Algorithm and Its Variations,'' Algorithmica 1, 2 (1986), 251-266. http://www.cs.arizona.edu/people/gene/PAPERS/diff.ps

Found it on the Wikipedia page on diff.

That's only for finding a diff though, not applying it as a patch. I think that application of a patch is actually a harder problem; due to the risk of conflicts. It would need some form of user-controlling feedback mechanism, to resolve conflicts.

Upvotes: 3

Paul Biggar
Paul Biggar

Reputation: 28739

It seems like the Google Diff, Match and Patch libraries are what you need.

Upvotes: 13

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