From 5f94e44cde18e3c48bc301438e1fadd73a2db520 Mon Sep 17 00:00:00 2001
From: Tony Hagale <tony@hagale.net>
Date: Wed, 19 Mar 2014 16:26:45 -0500
Subject: [PATCH] #2386 trying a new static lookup table for numberOfOnes()

---
 libraries/shared/src/SharedUtil.cpp | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/libraries/shared/src/SharedUtil.cpp b/libraries/shared/src/SharedUtil.cpp
index e5aded2798..00810653c1 100644
--- a/libraries/shared/src/SharedUtil.cpp
+++ b/libraries/shared/src/SharedUtil.cpp
@@ -130,14 +130,22 @@ void outputBits(unsigned char byte, QDebug* continuedDebug) {
 }
 
 int numberOfOnes(unsigned char byte) {
-    return (byte >> 7)
-        + ((byte >> 6) & 1)
-        + ((byte >> 5) & 1)
-        + ((byte >> 4) & 1)
-        + ((byte >> 3) & 1)
-        + ((byte >> 2) & 1)
-        + ((byte >> 1) & 1)
-        + (byte & 1);
+
+    static const unsigned char nbits[256] = {
+        0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,1,2,2,3,2,3,3,4,2,3,3,
+        4,3,4,4,5,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,
+        4,5,3,4,4,5,4,5,5,6,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,
+        3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,3,4,3,4,4,5,3,4,4,5,
+        4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,1,2,2,3,2,3,3,
+        4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,
+        3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,
+        6,6,7,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,
+        4,5,5,6,5,6,6,7,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,4,5,5,
+        6,5,6,6,7,5,6,6,7,6,7,7,8
+    };
+
+    return nbits[(unsigned char) byte];
+
 }
 
 bool oneAtBit(unsigned char byte, int bitIndex) {