cosmopolitan/libc/intrin/sigcountset.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/struct/sigset.h"
#include "libc/intrin/popcnt.h"
#include "libc/macros.internal.h"
#include "libc/sysv/consts/limits.h"

/**
 * Returns population count of signal set.
 *
 * @return value greater than or equal to zero
 * @asyncsignalsafe
 */
int sigcountset(const sigset_t *set) {
  int r, i, x, y;
  switch (_NSIG) {
    case 32:
      x = (uint32_t)set->__bits[0];
      y = 0;
      break;
    case 64:
      x = set->__bits[0];
      y = 0;
      break;
    case 128:
      x = set->__bits[0];
      y = set->__bits[1];
      break;
    default:
      notpossible;
  }
  return popcnt(x) + popcnt(y);
}