md: Factor out RAID6 algorithms into lib/

We'll want to use these in btrfs too.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/raid6/unroll.pl b/lib/raid6/unroll.pl
new file mode 100644
index 00000000000..3acc710a20e
--- /dev/null
+++ b/lib/raid6/unroll.pl
@@ -0,0 +1,24 @@
+#!/usr/bin/perl
+#
+# Take a piece of C code and for each line which contains the sequence $$
+# repeat n times with $ replaced by 0...n-1; the sequence $# is replaced
+# by the unrolling factor, and $* with a single $
+#
+
+($n) = @ARGV;
+$n += 0;
+
+while ( defined($line = <STDIN>) ) {
+    if ( $line =~ /\$\$/ ) {
+	$rep = $n;
+    } else {
+	$rep = 1;
+    }
+    for ( $i = 0 ; $i < $rep ; $i++ ) {
+	$tmp = $line;
+	$tmp =~ s/\$\$/$i/g;
+	$tmp =~ s/\$\#/$n/g;
+	$tmp =~ s/\$\*/\$/g;
+	print $tmp;
+    }
+}