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/*
* Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
*
* Permission to use, copy, modify, and 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.
*/
#undef NDEBUG
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
static unsigned long long xstrtoull(const char *p, char **end)
{
if (*p == '0') {
*end = (char *)p + 1;
return 0;
} else if ('1' <= *p && *p <= '9') {
unsigned long long val;
errno = 0;
val = strtoull(p, end, 10);
assert(errno == 0);
return val;
} else
assert(0);
}
static void proc_uptime(int fd, uint64_t *uptime, uint64_t *idle)
{
uint64_t val1, val2;
char buf[64], *p;
ssize_t rv;
/* save "p < end" checks */
memset(buf, 0, sizeof(buf));
rv = pread(fd, buf, sizeof(buf), 0);
assert(0 <= rv && rv <= sizeof(buf));
buf[sizeof(buf) - 1] = '\0';
p = buf;
val1 = xstrtoull(p, &p);
assert(p[0] == '.');
assert('0' <= p[1] && p[1] <= '9');
assert('0' <= p[2] && p[2] <= '9');
assert(p[3] == ' ');
val2 = (p[1] - '0') * 10 + p[2] - '0';
*uptime = val1 * 100 + val2;
p += 4;
val1 = xstrtoull(p, &p);
assert(p[0] == '.');
assert('0' <= p[1] && p[1] <= '9');
assert('0' <= p[2] && p[2] <= '9');
assert(p[3] == '\n');
val2 = (p[1] - '0') * 10 + p[2] - '0';
*idle = val1 * 100 + val2;
assert(p + 4 == buf + rv);
}
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