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Diffstat (limited to 'butl/timestamp.cxx')
| -rw-r--r-- | butl/timestamp.cxx | 612 |
1 files changed, 0 insertions, 612 deletions
diff --git a/butl/timestamp.cxx b/butl/timestamp.cxx deleted file mode 100644 index 971f1ef..0000000 --- a/butl/timestamp.cxx +++ /dev/null @@ -1,612 +0,0 @@ -// file : butl/timestamp.cxx -*- C++ -*- -// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd -// license : MIT; see accompanying LICENSE file - -#include <butl/timestamp> - -#include <time.h> // localtime_{r,s}(), gmtime_{r,s}(), strptime(), timegm() -#include <errno.h> // EINVAL - -#include <ctime> // tm, time_t, mktime() -#include <cstdlib> // strtoull() -#include <cassert> -#include <iomanip> // put_time(), setw(), dec, right -#include <cstring> // strlen(), memcpy() -#include <ostream> -#include <utility> // pair, make_pair() -#include <stdexcept> // runtime_error - -#include <butl/utility> // throw_generic_error() - -using namespace std; - -// libstdc++ prior to GCC 5 does not have std::put_time() so we have to invent -// our own. Detecting the "prior to GCC 5" condition, however, is not easy: -// libstdc++ is used by other compilers (e.g., Clang) so we cannot just use -// __GNUC__. There is __GLIBCXX__ but it is a date which is updated with -// every release, including bugfixes (so, there can be some 4.7.X release with -// a date greater than 5.0.0). -// -// So what we going to do here is "offer" our implementation and let the ADL -// pick one. If there is std::put_time(), then it will be preferred because -// of the std::tm argument. -// -#ifdef __GLIBCXX__ - -#include <ctime> // tm, strftime() -#include <ostream> - -namespace details -{ - struct put_time_data - { - const std::tm* tm; - const char* fmt; - }; - - inline put_time_data - put_time (const std::tm* tm, const char* fmt) - { - return put_time_data {tm, fmt}; - } - - inline ostream& - operator<< (ostream& os, const put_time_data& d) - { - char buf[256]; - if (strftime (buf, sizeof (buf), d.fmt, d.tm) != 0) - os << buf; - else - os.setstate (ostream::badbit); - return os; - } -} - -using namespace details; - -#endif - -// Thread-safe implementations of gmtime() and localtime(). -// -// Normally we would provide POSIX function replacement for Windows if the -// original function is absent. However, MinGW GCC can sometimes provide them. -// And so to avoid name clashes we hide them in the details namespace. -// -// Previously we have used gmtime_s() and localtime_s() for gmtime() and -// localtime() implementations for Windows, but that required Security-Enhanced -// version of CRT to be present, which is not always the case. In particular if -// MinGW is configured with --disable-secure-api option then declarations of -// *_s() functions are not available. So we use ::gmtime() and ::localtime() -// for that purpose. Note that according to MSDN "gmtime and localtime all use -// one common tm structure per thread for the conversion", which mean that they -// are thread-safe. -// -namespace details -{ - static tm* - gmtime (const time_t* t, tm* r) - { -#ifdef _WIN32 - const tm* gt (::gmtime (t)); - if (gt == nullptr) - return nullptr; - - *r = *gt; - return r; -#else - return gmtime_r (t, r); -#endif - } - - static tm* - localtime (const time_t* t, tm* r) - { -#ifdef _WIN32 - const tm* lt (::localtime (t)); - if (lt == nullptr) - return nullptr; - - *r = *lt; - return r; -#else - return localtime_r (t, r); -#endif - } -} - -namespace butl -{ - ostream& - to_stream (ostream& os, - const timestamp& ts, - const char* format, - bool special, - bool local) - { - if (special) - { - if (ts == timestamp_unknown) - return os << "<unknown>"; - - if (ts == timestamp_nonexistent) - return os << "<nonexistent>"; - } - - time_t t (system_clock::to_time_t (ts)); - - std::tm tm; - if ((local - ? details::localtime (&t, &tm) - : details::gmtime (&t, &tm)) == nullptr) - throw_generic_error (errno); - - using namespace chrono; - - timestamp sec (system_clock::from_time_t (t)); - nanoseconds ns (duration_cast<nanoseconds> (ts - sec)); - - char fmt[256]; - size_t n (strlen (format)); - if (n + 1 > sizeof (fmt)) - throw_generic_error (EINVAL); - memcpy (fmt, format, n + 1); - - // Chunk the format string into fragments that we feed to put_time() and - // those that we handle ourselves. Watch out for the escapes (%%). - // - size_t i (0), j (0); // put_time()'s range. - for (; j != n; ++j) - { - if (fmt[j] == '%' && j + 1 != n) - { - if (fmt[j + 1] == '[') - { - if (os.width () != 0) - throw runtime_error ( - "padding is not supported when printing nanoseconds"); - - // Our fragment. First see if we need to call put_time(). - // - if (i != j) - { - fmt[j] = '\0'; - if (!(os << put_time (&tm, fmt + i))) - return os; - } - - j += 2; // Character after '['. - if (j == n) - throw_generic_error (EINVAL); - - char d ('\0'); - if (fmt[j] != 'N') - { - d = fmt[j]; - if (++j == n || fmt[j] != 'N') - throw_generic_error (EINVAL); - } - - if (++j == n || fmt[j] != ']') - throw_generic_error (EINVAL); - - if (ns != nanoseconds::zero ()) - { - if (d != '\0') - os << d; - - ostream::fmtflags fl (os.flags ()); - char fc (os.fill ('0')); - os << dec << right << setw (9) << ns.count (); - os.fill (fc); - os.flags (fl); - } - - i = j + 1; // j is incremented in the for-loop header. - } - else - ++j; // Skip % and the next character to handle %%. - } - } - - // Do we need to call put_time() one last time? - // - if (i != j) - { - if (!(os << put_time (&tm, fmt + i))) - return os; - } - - return os; - } - - ostream& - operator<< (ostream& os, const duration& d) - { - if (os.width () != 0) // We always print nanosecond. - throw runtime_error ( - "padding is not supported when printing nanoseconds"); - - timestamp ts; // Epoch. - ts += d; - - time_t t (system_clock::to_time_t (ts)); - - const char* fmt (nullptr); - const char* unt ("nanoseconds"); - if (t >= 365 * 24 * 60 * 60) - { - fmt = "%Y-%m-%d %H:%M:%S"; - unt = "years"; - } - else if (t >= 31 * 24 * 60 * 60) - { - fmt = "%m-%d %H:%M:%S"; - unt = "months"; - } - else if (t >= 24 * 60 * 60) - { - fmt = "%d %H:%M:%S"; - unt = "days"; - } - else if (t >= 60 * 60) - { - fmt = "%H:%M:%S"; - unt = "hours"; - } - else if (t >= 60) - { - fmt = "%M:%S"; - unt = "minutes"; - } - else if (t >= 1) - { - fmt = "%S"; - unt = "seconds"; - } - - if (fmt != nullptr) - { - std::tm tm; - if (details::gmtime (&t, &tm) == nullptr) - throw_generic_error (errno); - - if (t >= 24 * 60 * 60) - tm.tm_mday -= 1; // Make day of the month to be a zero-based number. - - if (t >= 31 * 24 * 60 * 60) - tm.tm_mon -= 1; // Make month of the year to be a zero-based number. - - if (t >= 365 * 24 * 60 * 60) - // Make the year to be a 1970-based number. Negative values allowed - // according to the POSIX specification. - // - tm.tm_year -= 1970; - - if (!(os << put_time (&tm, fmt))) - return os; - } - - using namespace chrono; - - timestamp sec (system_clock::from_time_t (t)); - nanoseconds ns (duration_cast<nanoseconds> (ts - sec)); - - if (ns != nanoseconds::zero ()) - { - if (fmt != nullptr) - { - ostream::fmtflags fl (os.flags ()); - char fc (os.fill ('0')); - os << '.' << dec << right << setw (9) << ns.count (); - os.fill (fc); - os.flags (fl); - } - else - os << ns.count (); - - os << ' ' << unt; - } - else if (fmt == nullptr) - os << '0'; - - return os; - } -} - -// Implementation of strptime() and timegm() for Windows. -// -// Here we have several cases. If this is VC++, then we implement strptime() -// via C++11 std::get_time(). And if this is MINGW GCC (or, more precisely, -// libstdc++), then we have several problems. Firstly, GCC prior to 5 doesn't -// implement std::get_time(). Secondly, GCC 5 and even 6 have buggy -// std::get_time() (it cannot parse single-digit days). So what we are going -// to do in this case is use a FreeBSD-based strptime() implementation. -// -#ifdef _WIN32 - -#ifdef __GLIBCXX__ - -// Fallback to a FreeBSD-based implementation. -// -extern "C" -{ -#include "strptime.c" -} - -#else // NOT __GLIBCXX__ - -#include <ctime> // tm -#include <locale> -#include <clocale> -#include <sstream> -#include <iomanip> -#include <cstring> // strlen() - -// VC++ std::get_time()-based implementation. -// -static char* -strptime (const char* input, const char* format, tm* time) -{ - istringstream is (input); - - // The original strptime() function behaves according to the process' C - // locale (set with std::setlocale()), which can differ from the process C++ - // locale (set with std::locale::global()). - // - is.imbue (locale (setlocale (LC_ALL, nullptr))); - - if (!(is >> get_time (time, format))) - return nullptr; - else - // tellg() behaves as UnformattedInputFunction, so returns failure status - // if eofbit is set. - // - return const_cast<char*> ( - input + (is.eof () - ? strlen (input) - : static_cast<size_t> (is.tellg ()))); -} - -#endif // __GLIBCXX__ - -#include <ctime> // time_t, tm, mktime() - -static time_t -timegm (tm* ctm) -{ - const time_t e (static_cast<time_t> (-1)); - - // We will use an example to explain how it works. Say *ctm contains 9 AM of - // some day. Note that no time zone information is available. - // - // Convert it to the time from Epoch as if it's in the local time zone. - // - ctm->tm_isdst = -1; - time_t t (mktime (ctm)); - if (t == e) - return e; - - // Let's say we are in Moscow, and t contains the time passed from Epoch till - // 9 AM MSK. But that is not what we need. What we need is the time passed - // from Epoch till 9 AM GMT. This is some bigger number, as it takes longer - // to achieve the same calendar time for more Western location. So we need to - // find that offset, and increment t with it to obtain the desired value. The - // offset is effectively the time difference between MSK and GMT time zones. - // - tm gtm; - if (details::gmtime (&t, >m) == nullptr) - return e; - - // gmtime() being called for the timepoint t returns 6 AM. So now we have - // *ctm and gtm, which value difference (3 hours) reflects the desired - // offset. The only problem is that we can not deduct gtm from *ctm, to get - // the offset expressed as time_t. To do that we need to apply to both of - // them the same conversion function transforming std::tm to std::time_t. The - // mktime() can do that, so the expression (mktime(ctm) - mktime(>m)) - // calculates the desired offset. - // - // To ensure mktime() works exactly the same way for both cases, we need to - // reset Daylight Saving Time flag for each of *ctm and gtm. - // - ctm->tm_isdst = 0; - time_t lt (mktime (ctm)); - if (lt == e) - return e; - - gtm.tm_isdst = 0; - time_t gt (mktime (>m)); - if (gt == e) - return e; - - // C11 standard specifies time_t to be a real type (integer and real floating - // types are collectively called real types). So we can not consider it to be - // signed. - // - return lt > gt ? t + (lt - gt) : t - (gt - lt); -} - -#endif // _WIN32 - -namespace butl -{ - static pair<tm, chrono::nanoseconds> - from_string (const char* input, const char* format, const char** end) - { - auto bad_val = [] () {throw_generic_error (EINVAL);}; - - // See if we have our specifier. - // - size_t i (0); - size_t n (strlen (format)); - for (; i != n; ++i) - { - if (format[i] == '%' && i + 1 != n) - { - if (format[i + 1] == '[') - break; - else - ++i; // To handle %%. - } - } - - // Call the fraction of a second as just fraction from now on. - // - using namespace chrono; - nanoseconds ns (nanoseconds::zero ()); - - if (i == n) - { - // No %[], so just parse with strptime(). - // - tm t = tm (); - const char* p (strptime (input, format, &t)); - if (p == nullptr) - bad_val (); - - if (end != nullptr) - *end = p; - else if (*p != '\0') - bad_val (); // Input is not fully read. - - t.tm_isdst = -1; - return make_pair (t, ns); - } - - // Now the overall plan is: - // - // 1. Parse the fraction part of the input string to obtain nanoseconds. - // - // 2. Remove fraction part from the input string. - // - // 3. Remove %[] from the format string. - // - // 4. Re-parse the modified input with the modified format to fill the - // std::tm structure. - // - // Parse the %[] specifier. - // - assert (format[i] == '%'); - string fm (format, i++); // Start assembling the new format string. - - assert (format[i] == '['); - if (++i == n) - bad_val (); - - char d (format[i]); // Delimiter character. - if (++i == n) - bad_val (); - - char f (format[i]); // Fraction specifier character. - if ((f != 'N' && f != 'U' && f != 'M') || ++i == n) - bad_val (); - - if (format[i++] != ']') - bad_val (); - - // Parse the input with the initial part of the format string, the one - // that preceeds the %[] specifier. The returned pointer will be the - // position we need to start from to parse the fraction. - // - tm t = tm (); - - // What if %[] is first, there is nothing before it? According to the - // strptime() documentation an empty format string is a valid one. - // - const char* p (strptime (input, fm.c_str (), &t)); - if (p == nullptr) - bad_val (); - - // Start assembling the new input string. - // - string in (input, p - input); - size_t fn (0); // Fraction size. - - if (d == *p) - { - // Fraction present in the input. - // - - // Read fraction digits. - // - char buf [10]; - size_t i (0); - size_t n (f == 'N' ? 9 : (f == 'U' ? 6 : 3)); - for (++p; i < n && *p >= '0' && *p <= '9'; ++i, ++p) - buf[i] = *p; - - if (i < n) - bad_val (); - - buf[n] = '\0'; - fn = n; - - // Calculate nanoseconds. - // - char* e (nullptr); - unsigned long long t (strtoull (buf, &e, 10)); - assert (e == buf + n); - - switch (f) - { - case 'N': ns = nanoseconds (t); break; - case 'U': ns = microseconds (t); break; - case 'M': ns = milliseconds (t); break; - default: assert (false); - } - - // Actually the idea to fully remove the fraction from the input string, - // and %[] from the format string, has a flaw. After the fraction removal - // the spaces around it will be "swallowed" with a single space in the - // format string. So, as an example, for the input: - // - // 2016-02-21 19:31:10 .384902285 GMT - // - // And the format: - // - // %Y-%m-%d %H:%M:%S %[.N] - // - // The unparsed tail of the input will be 'GMT' while expected to be - // ' GMT'. To fix that we will not remove, but replace the mentioned - // parts with some non-space character. - // - fm += '-'; - in += '-'; - } - - fm += format + i; - in += p; - - // Reparse the modified input with the modified format. - // - t = tm (); - const char* b (in.c_str ()); - p = strptime (b, fm.c_str (), &t); - - if (p == nullptr) - bad_val (); - - if (end != nullptr) - *end = input + (p - b + fn); - else if (*p != '\0') - bad_val (); // Input is not fully read. - - t.tm_isdst = -1; - return make_pair (t, ns); - } - - timestamp - from_string (const char* input, - const char* format, - bool local, - const char** end) - { - pair<tm, chrono::nanoseconds> t (from_string (input, format, end)); - - time_t time (local ? mktime (&t.first) : timegm (&t.first)); - if (time == -1) - throw_generic_error (errno); - - return timestamp::clock::from_time_t (time) + - chrono::duration_cast<duration> (t.second); - } -} |