vcs-svn: parse svndiff0 window header
Each window in a subversion delta (svndiff0-format file) starts with a
window header, consisting of five integers with variable-length
representation:
source view offset
source view length
output length
instructions length
auxiliary data length
Parse it. The result is not usable for deltas with nonempty postimage
yet; in fact, this only adds support for deltas without any
instructions or auxiliary data. This is a good place to stop, though,
since that little support lets us add some simple passing tests
concerning error handling to the test suite.
Improved-by: Ramkumar Ramachandra <artagnon@gmail.com>
Improved-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>