# Question: libxdiff: text-patches: internal format

2 messages from 2017-03-23 to 2017-03-23. Participants: matthew@giassa.net, René Scharfe.
Thread: https://gitlist.dev/t/45486

## matthew@giassa.net, 2017-03-23 18:00

Subject: Question: libxdiff: text-patches: internal format
Message-ID: <20170323180026.7qdfdzqgyczt2s3f@darkstar>
URL: https://gitlist.dev/e/20170323180026.7qdfdzqgyczt2s3f%40darkstar

```
Hi there,

Following up on an earlier question of mine from yesterday, is there any
formal documentation (save for source diving) on the internal format
used by libxdiff/xdiff when it generates a patch by comparing two
plaintext files?

I'd like to generate a human-readable "pretty" diff from the output
generated by libxdiff, and while the suggestion by Stefan yesterday is a
good idea (ie: go through diff.c), I'm trying to see if there's a
quicker way to pull this off. Also, I can't determine if lifting that
code from git would invoke LGPL licensing constraints (no problem), or
GPL licensing constraints (incompatible with my application). If the
format is easy enough to follow, I might just write my own parser,
provided it's a trivial task.

Thank you.

-- 
Matthew Giassa
e: matthew@giassa.net


```

## René Scharfe, 2017-03-23 19:30

Subject: Re: Question: libxdiff: text-patches: internal format
Message-ID: <e19893df-0f7c-cfa7-cca4-014630ccf908@web.de>
URL: https://gitlist.dev/e/e19893df-0f7c-cfa7-cca4-014630ccf908%40web.de
In-Reply-To: <20170323180026.7qdfdzqgyczt2s3f@darkstar>

```
Am 23.03.2017 um 19:00 schrieb matthew@giassa.net:
> Hi there,
>
> Following up on an earlier question of mine from yesterday, is there any
> formal documentation (save for source diving) on the internal format
> used by libxdiff/xdiff when it generates a patch by comparing two
> plaintext files?
>
> I'd like to generate a human-readable "pretty" diff from the output
> generated by libxdiff, and while the suggestion by Stefan yesterday is a
> good idea (ie: go through diff.c), I'm trying to see if there's a
> quicker way to pull this off. Also, I can't determine if lifting that
> code from git would invoke LGPL licensing constraints (no problem), or
> GPL licensing constraints (incompatible with my application). If the
> format is easy enough to follow, I might just write my own parser,
> provided it's a trivial task.

Some of your questions may be answered on the homepage of LibXDiff, 
http://www.xmailserver.org/xdiff-lib.html.  That's the original version 
that was imported into Git long ago.  It lacks some Git-specific 
features, but the documentation and links on the web page may still help 
you.  The original LibXDiff is licensed under the LGPL and perhaps you 
can use it directly already.

René

```