From efd2b41c35d427c78c685b9a543578df3641135d Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Sat, 16 May 2015 00:26:24 +0000 Subject: - add bitarray_count - add openwritevnclose_at - rc for 2.3.5.0 --- src/libstddjb/bitarray_count.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) create mode 100644 src/libstddjb/bitarray_count.c (limited to 'src/libstddjb') diff --git a/src/libstddjb/bitarray_count.c b/src/libstddjb/bitarray_count.c new file mode 100644 index 0000000..724f2b3 --- /dev/null +++ b/src/libstddjb/bitarray_count.c @@ -0,0 +1,20 @@ +/* ISC license. */ + +#include + +#define B0(n) n, n+1, n+1, n+2 +#define B1(n) B0(n), B0(n+1), B0(n+1), B0(n+2) +#define B2(n) B1(n), B1(n+1), B1(n+1), B1(n+2) +#define B3(n) B2(n), B2(n+1), B2(n+1), B2(n+2) + +unsigned int bitarray_countones (unsigned char const *c, unsigned int n) +{ + static unsigned char const table[256] = { B3(0) } ; + unsigned int len = bitarray_div8(n) ; + unsigned int total = 0 ; + register unsigned int i = 0 ; + if (n & 7) len-- ; + for (; i < len ; i++) total += table[c[i]] ; + if (n & 7) total += table[c[i] & ((1 << (n & 7)) - 1)] ; + return total ; +} -- cgit v1.2.3