"git diff" learned a variant of the "--patience" algorithm, to
which the user can specify which 'unique' line to be used as
anchoring points.

* jt/diff-anchored-patience:
  diff: support anchoring line(s)

"git grep -W", "git diff -W" and their friends learned a heuristic
to extend a pre-context beyond the line that matches the "function
pattern" (aka "diff.*.xfuncname") to include a comment block, if
exists, that immediately precedes it.

* rs/include-comments-before-the-function-header:
  grep: show non-empty lines before functions with -W
  grep: update boundary variable for pre-context
  t7810: improve check of -W with user-defined function lines
  xdiff: show non-empty lines before functions with -W
  xdiff: factor out is_func_rec()
  t4051: add test for comments preceding function lines

Teach diff a new algorithm, one that attempts to prevent user-specified
lines from appearing as a deletion or addition in the end result. The
end user can use this by specifying "--anchored=<text>" one or more
times when using Git commands like "diff" and "show".

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

The "diff" family of commands learned to ignore differences in
carriage return at the end of line.

* jc/ignore-cr-at-eol:
  diff: --ignore-cr-at-eol
  xdiff: reassign xpparm_t.flags bits

Non-empty lines before a function definition are most likely comments
for that function and thus relevant.  Include them in function context.

Such a non-empty line might also belong to the preceeding function if
there is no separating blank line.  Stop extending the context upwards
also at the next function line to make sure only one extra function body
is shown at most.

Original-patch-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Add a helper for checking if a given record is a function line.  It
frees callers from having to deal with the buffer arguments of
match_func_rec().

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

The mailing address for the FSF has changed over the years.  Rather than
updating the address across all files, refer readers to gnu.org, as the
GNU GPL documentation now suggests for license notices.  The mailing
address is retained in the full license files (COPYING and LGPL-2.1).

The old address is still present in t/diff-lib/COPYING.  This is
intentional, as the file is used in tests and the contents are not
expected to change.

Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

A new option --ignore-cr-at-eol tells the diff machinery to treat a
carriage-return at the end of a (complete) line as if it does not
exist.

Just like other "--ignore-*" options to ignore various kinds of
whitespace differences, this will help reviewing the real changes
you made without getting distracted by spurious CRLF<->LF conversion
made by your editor program.

Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
[jch: squashed in command line completion by Dscho]
Signed-off-by: Junio C Hamano <gitster@pobox.com>

We have packed the bits too tightly in such a way that it is not
easy to add a new type of whitespace ignoring option, a new type
of LCS algorithm, or a new type of post-cleanup heuristics.

Reorder bits a bit to give room for these three classes of options
to grow.  Also make use of XDF_WHITESPACE_FLAGS macro where we check
any of these bits are on, instead of using DIFF_XDL_TST() macro on
individual possibilities.  That way, the "is any of the bits on?"
code does not have to change when we add more ways to ignore
whitespaces.

While at it, add a comment in front of the bit definitions to
clarify in which structure these defined bits may appear.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

A common mistake when writing binary search is to allow possible
integer overflow by using the simple average:

	mid = (min + max) / 2;

Instead, use the overflow-safe version:

	mid = min + (max - min) / 2;

This translation is safe since the operation occurs inside a loop
conditioned on "min < max". The included changes were found using
the following git grep:

	git grep '/ *2;' '*.c'

Making this cleanup will prevent future review friction when a new
binary search is contructed based on existing code.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>