From f90fd9eeb32469e41c8f4207afa44929f9ec070e Mon Sep 17 00:00:00 2001
From: Alex Ray <aray@google.com>
Date: Sat, 19 Jan 2013 22:53:46 -0800
Subject: cutils: bitops: Add Hamming weight to bitmask

Change-Id: I5c6b7adf711007edfffcb4fdf8e05b04bcffef54
---
 include/cutils/bitops.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'include/cutils/bitops.h')

diff --git a/include/cutils/bitops.h b/include/cutils/bitops.h
index eb44236..c26dc54 100644
--- a/include/cutils/bitops.h
+++ b/include/cutils/bitops.h
@@ -75,6 +75,16 @@ static inline int bitmask_ffz(unsigned int *bitmask, int num_bits)
     return -1;
 }
 
+static inline int bitmask_weight(unsigned int *bitmask, int num_bits)
+{
+    int i;
+    int weight = 0;
+
+    for (i = 0; i < BITS_TO_WORDS(num_bits); i++)
+        weight += __builtin_popcount(bitmask[i]);
+    return weight;
+}
+
 static inline void bitmask_set(unsigned int *bitmask, int bit)
 {
     bitmask[BIT_WORD(bit)] |= BIT_MASK(bit);
-- 
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