/* +++Date last modified: 05-Jul-1997 */ /* ** Bit counter by Ratko Tomic */ #include "bitcount-bitops.h" int CDECL bit_count(long x) { int n = 0; /* ** The loop will execute once for each bit of x set, this is in average ** twice as fast as the shift/test method. */ if (x) do n++; while (0 != (x = x&(x-1))) ; return(n); } #ifdef TEST #include #include "snip_str.h" /* For plural_text() macro */ main(int argc, char *argv[]) { long n; while(--argc) { int i; n = atol(*++argv); i = bit_count(n); printf("%ld contains %d bit%s set\n", n, i, plural_text(i)); } return 0; } #endif /* TEST */