Add 'git-bdiff' utility

1 files changed, 51 insertions, 0 deletions

diff --git a/git-bdiff b/git-bdiff
new file mode 100755
index 0000000..9b39ad4
--- /dev/null
+++ b/git-bdiff
@@ -0,0 +1,51 @@
+#!/usr/bin/perl
+
+# git-bdiff -- fake compare binary files
+
+use strict;
+use warnings;
+
+my $i;
+
+if (@ARGV == 1) {
+	$i = 0;
+} elsif (@ARGV == 7) {
+	$i = 4;
+} else {
+	die <<USAGE
+usage: $0 file
+    or $0 a t A s b B S
+USAGE
+}
+
+my @deps;
+(my $path = $ARGV[$i]) =~ s,[^/]*$,,;
+(my $target = $ARGV[$i]) =~ s,.*/,,;
+(my $ext = $target) =~ s/.*\.//;
+(my $basename = $target) =~ s/\.[^.]*$//;
+chomp(my $repo = `git rev-parse --show-toplevel`);
+
+open my $f, '<', "$repo/${path}Makefile"
+	or die "could not open $repo/${path}Makefile: $!\n";
+while (<$f>) {
+	# explicit
+	if (/^\Q$target\E:\s*(.*)/) {
+		push @deps, "$repo/$path$_" for split /\s/, $1;
+		last;
+	}
+	# implicit
+	if (/^\.([^ .]+)\.\Q$ext\E\s*:\s*(.*)/) {
+		push @deps, "$repo/$path$basename.$1";
+		push @deps, "$repo/$path$_" for split /\s/, $2;
+		last;
+	}
+}
+close $f;
+die "no dependencies found, cannot compare\n" if not @deps;
+
+$i = 0;
+for (`git diff HEAD -- @deps`) {
+	print if @ARGV == 7;
+	$i = 1;
+}
+exit $i if @ARGV == 1;