// Fallback for platforms (such as WASM) that aren't covered above.

int num_cpus = 0;

int max_id = -1;

std::ifstream f("/proc/cpuinfo");

if (!f.is_open()) {

std::cerr << "Failed to open /proc/cpuinfo\n";

return -1;

}

#if defined(__alpha__)

const std::string Key = "cpus detected";

#else

const std::string Key = "processor";

#endif

std::string ln;

while (std::getline(f, ln)) {

if (ln.empty()) continue;

std::size_t split_idx = ln.find(':');

std::string value;

#if defined(__s390__)

// s390 has another format in /proc/cpuinfo

// it needs to be parsed differently

if (split_idx != std::string::npos)

value = ln.substr(Key.size() + 1, split_idx - Key.size() - 1);

#else

if (split_idx != std::string::npos) value = ln.substr(split_idx + 1);

#endif

if (ln.size() >= Key.size() && ln.compare(0, Key.size(), Key) == 0) {

num_cpus++;

if (!value.empty()) {

const int cur_id = benchmark::stoi(value);

max_id = std::max(cur_id, max_id);

}

}

}

if (f.bad()) {

PrintErrorAndDie("Failure reading /proc/cpuinfo");

}

if (!f.eof()) {

PrintErrorAndDie("Failed to read to end of /proc/cpuinfo");

}

f.close();

if ((max_id + 1) != num_cpus) {

fprintf(stderr,

"CPU ID assignments in /proc/cpuinfo seem messed up."

" This is usually caused by a bad BIOS.\n");

}

return num_cpus;