[PATCH v3, 06/16] xfsprogs: metadump: replace repeated blocks with a loop

[PATCH v3, 06/16] xfsprogs: metadump: replace repeated blocks with a loop

[Alex Elder]

Each of the last five characters in the obfuscated name are
generated the same way.  Replace that repeated block of code
with an equivalent loop.

Signed-off-by: Alex Elder <aelder@sgi.com>

No significant changes in this version from the last one posted.

---
 db/metadump.c |   43 +++++++++----------------------------------
 1 file changed, 9 insertions(+), 34 deletions(-)

Index: b/db/metadump.c
===================================================================
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -501,41 +501,16 @@ generate_obfuscated_name(
 		newhash = rol32(newhash, 3) ^ hash;
 
 		high_bit = 0;
+		for (i = 5; i > 0; i--) {
+		    	int shift = (i - 1) * 7;
 
-		newp[namelen - 5] = ((newhash >> 28) & 0x7f) ^ high_bit;
-		if (is_invalid_char(newp[namelen - 5])) {
-			newp[namelen - 5] ^= 1;
-			high_bit = 0x80;
-		} else
-			high_bit = 0;
-
-		newp[namelen - 4] = ((newhash >> 21) & 0x7f) ^ high_bit;
-		if (is_invalid_char(newp[namelen - 4])) {
-			newp[namelen - 4] ^= 1;
-			high_bit = 0x80;
-		} else
-			high_bit = 0;
-
-		newp[namelen - 3] = ((newhash >> 14) & 0x7f) ^ high_bit;
-		if (is_invalid_char(newp[namelen - 3])) {
-			newp[namelen - 3] ^= 1;
-			high_bit = 0x80;
-		} else
-			high_bit = 0;
-
-		newp[namelen - 2] = ((newhash >> 7) & 0x7f) ^ high_bit;
-		if (is_invalid_char(newp[namelen - 2])) {
-			newp[namelen - 2] ^= 1;
-			high_bit = 0x80;
-		} else
-			high_bit = 0;
-
-		newp[namelen - 1] = ((newhash >> 0) & 0x7f) ^ high_bit;
-		if (is_invalid_char(newp[namelen - 1])) {
-			newp[namelen - 1] ^= 1;
-			high_bit = 0x80;
-		} else
-			high_bit = 0;
+			newp[namelen - i] = ((newhash >> shift) & 0x7f) ^ high_bit;
+			if (is_invalid_char(newp[namelen - i])) {
+				newp[namelen - i] ^= 1;
+				high_bit = 0x80;
+			} else
+				high_bit = 0;
+		}
 
 		/*
 		 * If we flipped a bit on the last byte, we need to

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Re: [PATCH v3, 06/16] xfsprogs: metadump: replace repeated blocks with a loop

[Dave Chinner]

On Fri, Feb 18, 2011 at 03:21:01PM -0600, Alex Elder wrote:
> Each of the last five characters in the obfuscated name are
> generated the same way.  Replace that repeated block of code
> with an equivalent loop.
> 
> Signed-off-by: Alex Elder <aelder@sgi.com>

Nice simplification.

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com

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