/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-â
âvi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :viâ
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â Copyright 2022 Justine Alexandra Roberts Tunney                              â
â                                                                              â
â Permission to use, copy, modify, and/or distribute this software for         â
â any purpose with or without fee is hereby granted, provided that the         â
â above copyright notice and this permission notice appear in all copies.      â
â                                                                              â
â THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                â
â WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                â
â WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             â
â AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         â
â DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        â
â PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               â
â TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             â
â PERFORMANCE OF THIS SOFTWARE.                                                â
ââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ*/
#include "libc/calls/struct/timeval.h"
#include "libc/limits.h"

/**
 * Converts timeval to scalar.
 *
 * This returns the absolute number of microseconds in a timeval. If
 * overflow happens, then `INT64_MAX` or `INT64_MIN` is returned. The
 * `errno` variable isn't changed.
 *
 * @return 64-bit integer holding microseconds since epoch
 */
int64_t timeval_tomicros(struct timeval x) {
  int64_t ns;
  if (!__builtin_mul_overflow(x.tv_sec, 1000000ul, &ns) &&
      !__builtin_add_overflow(ns, x.tv_usec, &ns)) {
    return ns;
  } else if (x.tv_sec < 0) {
    return INT64_MIN;
  } else {
    return INT64_MAX;
  }
}
