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/* See LICENSE file for copyright and license details. */
#include "common.h"
size_t
getnproc(size_t default_count)
{
char buf[128];
int fd, num = 0;
size_t n = 0, off = 0, len = 0;
size_t nums[] = {0, 0};
ssize_t r;
size_t last = 0;
fd = open("/sys/devices/system/cpu/online", O_RDONLY);
if (fd < 0)
return default_count;
for (;; off++) {
if (off == len) {
r = read(fd, buf, sizeof(buf));
if (r <= 0) {
if (!r)
break;
if (errno == EINTR)
continue;
error:
n = default_count;
goto out;
}
len = (size_t)r;
off = 0;
}
if (buf[off] == '-') {
if (num++ == 1)
goto error;
} else if (buf[off] == ',' || buf[off] == '\n') {
if (num == 0) {
nums[1] = nums[0];
} else {
num = 0;
if (nums[1] < nums[0])
goto error;
}
if (nums[0] < last)
goto error;
last = nums[0];
if (nums[1] - nums[0] + 1U > SIZE_MAX - n)
goto error;
n += nums[1] - nums[0] + 1U;
} else if (isdigit(buf[off])) {
if (nums[num] > (SIZE_MAX - (size_t)(buf[off] & 15)) / 10U)
goto error;
nums[num] = nums[num] * 10U + (size_t)(buf[off] & 15);
} else {
goto error;
}
}
n = n ? n : default_count;
out:
close(fd);
return n;
}
size_t
getautonthreads(void)
{
size_t n = getnproc(8U);
return n < 3U ? 1U : n - 2U;
}
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