137 lines
3.6 KiB
C++
137 lines
3.6 KiB
C++
// Copyright 2017, University of Freiburg,
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// Chair of Algorithms and Data Structures.
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// Authors: Patrick Brosi <brosi@informatik.uni-freiburg.de>
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#ifndef UTIL_MISC_H_
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#define UTIL_MISC_H_
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#include <cmath>
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#include <cstring>
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#include <chrono>
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#include <sstream>
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#include <unistd.h>
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#include <sys/types.h>
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#include <pwd.h>
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#define UNUSED(expr) do { (void)(expr); } while (0)
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#define TIME() std::chrono::high_resolution_clock::now()
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#define TOOK(t1, t2) (std::chrono::duration_cast<microseconds>(t2 - t1).count() / 1000.0)
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#define T_START(n) auto _tstart_##n = std::chrono::high_resolution_clock::now()
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#define T_STOP(n) (std::chrono::duration_cast<microseconds>(std::chrono::high_resolution_clock::now() - _tstart_##n).count() / 1000.0)
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namespace util {
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// cached first 10 powers of 10
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static int pow10[10] = {
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1, 10, 100, 1000, 10000,
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100000, 1000000, 10000000, 100000000, 1000000000};
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// _____________________________________________________________________________
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inline uint64_t factorial(uint64_t n) {
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if (n == 1) return n;
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return n * factorial(n - 1);
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}
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// _____________________________________________________________________________
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inline uint64_t atoul(const char* p) {
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uint64_t ret = 0;
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while (*p) {
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ret = ret * 10 + (*p++ - '0');
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}
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return ret;
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}
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// _____________________________________________________________________________
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inline bool isFloatingPoint(const std::string& str) {
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std::stringstream ss(str);
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double f;
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ss >> std::noskipws >> f;
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return ss.eof() && ! ss.fail();
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}
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// _____________________________________________________________________________
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inline double atof(const char* p, uint8_t mn) {
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// this atof implementation works only on "normal" float strings like
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// 56.445 or -345.00, but should be faster than std::atof
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double ret = 0.0;
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bool neg = false;
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if (*p == '-') {
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neg = true;
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p++;
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}
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while (*p >= '0' && *p <= '9') {
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ret = ret * 10.0 + (*p - '0');
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p++;
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}
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if (*p == '.') {
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p++;
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double f = 0;
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uint8_t n = 0;
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for (; n < mn && *p >= '0' && *p <= '9'; n++, p++) {
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f = f * 10.0 + (*p - '0');
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}
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if (n < 10)
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ret += f / pow10[n];
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else
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ret += f / std::pow(10, n);
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}
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if (neg) return -ret;
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return ret;
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}
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// _____________________________________________________________________________
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inline double atof(const char* p) { return atof(p, 38); }
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// _____________________________________________________________________________
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inline std::string getHomeDir() {
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// parse implicit paths
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const char* homedir = 0;
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char* buf = 0;
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if ((homedir = getenv("HOME")) == 0) {
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homedir = "";
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struct passwd pwd;
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struct passwd* result;
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size_t bufsize;
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bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
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if (bufsize == static_cast<size_t>(-1)) bufsize = 0x4000;
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buf = static_cast<char*>(malloc(bufsize));
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if (buf != 0) {
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getpwuid_r(getuid(), &pwd, buf, bufsize, &result);
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if (result != NULL) homedir = result->pw_dir;
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}
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}
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std::string ret(homedir);
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if (buf) free(buf);
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return ret;
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}
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// _____________________________________________________________________________
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inline std::string getTmpDir() {
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// first, check if an env variable is set
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const char* tmpdir = getenv("TMPDIR");
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if (tmpdir && std::strlen(tmpdir)) return std::string(tmpdir);
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// second, check if /tmp is writable
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if (access("/tmp/", W_OK) == 0) return "/tmp";
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// third, check if the cwd is writable
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if (access(".", W_OK) == 0) return ".";
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// lastly, return the users home directory as a fallback
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return getHomeDir();
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}
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} // namespace util
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#endif // UTIL_MISC_H_
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