source/time/datetime.cpp

   1 #include <cstdlib>
   2 #include <stdexcept>
   3 #include <msp/strings/format.h>
   4 #include <msp/strings/regex.h>
   5 #include "datetime.h"
   6 #include "timestamp.h"
   7
   8 using namespace std;
   9
  10 namespace {
  11
  12 inline bool is_leap_year(int y)
  13 { return y%4==0 && (y%100 || y%400==0); }
  14
  15 inline unsigned char month_days(int y, unsigned char m)
  16 {
  17         switch(m)
  18         {
  19         case 4:
  20         case 6:
  21         case 9:
  22         case 11:
  23                 return 30;
  24         case 2:
  25                 return is_leap_year(y)?29:28;
  26         default:
  27                 return 31;
  28         }
  29 }
  30
  31 template<typename T>
  32 inline int _cmp(T a, T b)
  33 {
  34         if(a<b)
  35                 return -1;
  36         if(a>b)
  37                 return 1;
  38         return 0;
  39 }
  40
  41 }
  42
  43 namespace Msp {
  44 namespace Time {
  45
  46 DateTime::DateTime(const TimeStamp &ts)
  47 {
  48         add_raw(ts.raw());
  49 }
  50
  51 DateTime::DateTime(const TimeStamp &ts, const TimeZone &tz):
  52         DateTime(ts)
  53 {
  54         convert_timezone(tz);
  55 }
  56
  57 DateTime::DateTime(int y, unsigned char m, unsigned char d):
  58         DateTime(y, m, d, 0, 0, 0, 0)
  59 { }
  60
  61 DateTime::DateTime(int y, unsigned char m, unsigned char d, unsigned char h, unsigned char n, unsigned char s):
  62         DateTime(y, m, d, h, n, s, 0)
  63 { }
  64
  65 DateTime::DateTime(int y, unsigned char m, unsigned char d, unsigned char h, unsigned char n, unsigned char s, unsigned u):
  66         year(y),
  67         month(m),
  68         mday(d),
  69         hour(h),
  70         minute(n),
  71         second(s),
  72         usec(u)
  73 {
  74         if(usec>=1000000)
  75                 throw out_of_range("DateTime::DateTime usec");
  76         if(second>=60)
  77                 throw out_of_range("DateTime::DateTime second");
  78         if(minute>=60)
  79                 throw out_of_range("DateTime::DateTime minute");
  80         if(hour>=24)
  81                 throw out_of_range("DateTime::DateTime hour");
  82         if(month<1 || month>12)
  83                 throw out_of_range("DateTime::DateTime month");
  84         if(mday<1 || mday>month_days(year, month))
  85                 throw out_of_range("DateTime::DateTime mday");
  86 }
  87
  88 DateTime DateTime::parse_rfc3339(const string &str)
  89 {
  90         static Regex re("^([0-9]{4})-([0-9]{2})-([0-9]{2})T([0-9]{2}):([0-9]{2}):([0-9]{2})(.([0-9]+))?(Z|[-+]([0-9]{2}):([0-9]{2}))$");
  91
  92         RegMatch m = re.match(str);
  93         if(!m)
  94                 throw invalid_argument("DateTime::parse_rfc3339");
  95
  96         unsigned year = lexical_cast<unsigned>(m[1].str);
  97         unsigned month = lexical_cast<unsigned>(m[2].str);
  98         unsigned mday = lexical_cast<unsigned>(m[3].str);
  99         unsigned hr = lexical_cast<unsigned>(m[4].str);
 100         unsigned minute = lexical_cast<unsigned>(m[5].str);
 101         unsigned second = lexical_cast<unsigned>(m[6].str);
 102         unsigned us = 0;
 103         const string &sec_frac = m[8].str;
 104         if(!sec_frac.empty())
 105         {
 106                 us = lexical_cast<unsigned>(sec_frac);
 107                 for(unsigned i=sec_frac.size(); i<6; ++i)
 108                         us *= 10;
 109                 for(unsigned i=sec_frac.size(); i>6; --i)
 110                         us /= 10;
 111         }
 112
 113         DateTime result = DateTime(year, month, mday, hr, minute, second, us);
 114
 115         int tzoff = 0;
 116         if(m[9].str!="Z")
 117         {
 118                 tzoff = lexical_cast<unsigned>(m[10].str)*60+lexical_cast<unsigned>(m[11].str);
 119                 if(m[9].str[0]=='-')
 120                         tzoff = -tzoff;
 121         }
 122
 123         result.set_timezone(tzoff);
 124
 125         return result;
 126 }
 127
 128 void DateTime::add_days(int days)
 129 {
 130         int new_year = year;
 131
 132         /* Leap years have a 400 year cycle, so any 400 consecutive years have a
 133         constant number of days (400*365+97 = 146097) */
 134         new_year += days/146097*400;
 135         days %= 146097;
 136
 137         if(days<0)
 138         {
 139                 new_year -= 400;
 140                 days += 146097;
 141         }
 142
 143         // Fudge factor for leap day
 144         int fudge = (month<=2) ? 1 : 0;
 145
 146         // (Almost) every 4 year cycle has 1 leap year and 3 normal years
 147         unsigned cycles = days/1461;
 148         days %= 1461;
 149
 150         new_year += cycles*4;
 151
 152         // See how many non-leap-years we counted as leap years and reclaim the lost days
 153         // XXX This breaks with negative years
 154         unsigned missed_leap_days = ((year-fudge)%100+cycles*4)/100;
 155         if((year-fudge)%400+cycles*4>=400)
 156                 --missed_leap_days;
 157
 158         days += missed_leap_days;
 159
 160         // Count single years from the 4 year cycle
 161         cycles = days/365;
 162         days %= 365;
 163
 164         new_year += cycles;
 165
 166         if((year-fudge)%4+cycles>=4 && (new_year%100>=4 || new_year%400<4))
 167         {
 168                 // We passed a leap year - decrement days
 169                 if(days==0)
 170                 {
 171                         days = is_leap_year(new_year-fudge) ? 365 : 364;
 172                         --new_year;
 173                 }
 174                 else
 175                         --days;
 176         }
 177
 178         year = new_year;
 179
 180         // Step months
 181         while(mday+days>month_days(year, month))
 182         {
 183                 days -= month_days(year, month);
 184                 ++month;
 185                 if(month>12)
 186                 {
 187                         ++year;
 188                         month = 1;
 189                 }
 190         }
 191
 192         mday += days;
 193 }
 194
 195 void DateTime::set_timezone(const TimeZone &tz)
 196 {
 197         zone = tz;
 198 }
 199
 200 void DateTime::convert_timezone(const TimeZone &tz)
 201 {
 202         add_raw((tz.get_offset()-zone.get_offset()).raw());
 203         zone = tz;
 204 }
 205
 206 DateTime DateTime::operator+(const TimeDelta &td) const
 207 {
 208         DateTime dt(*this);
 209         dt.add_raw(td.raw());
 210         return dt;
 211 }
 212
 213 DateTime &DateTime::operator+=(const TimeDelta &td)
 214 {
 215         add_raw(td.raw());
 216         return *this;
 217 }
 218
 219 DateTime DateTime::operator-(const TimeDelta &td) const
 220 {
 221         DateTime dt(*this);
 222         dt.add_raw(-td.raw());
 223         return dt;
 224 }
 225
 226 DateTime &DateTime::operator-=(const TimeDelta &td)
 227 {
 228         add_raw(-td.raw());
 229         return *this;
 230 }
 231
 232 int DateTime::cmp(const DateTime &dt) const
 233 {
 234         if(int c = _cmp(year, dt.year))
 235                 return c;
 236         if(int c = _cmp(month, dt.month))
 237                 return c;
 238         if(int c = _cmp(mday, dt.mday))
 239                 return c;
 240         if(int c = _cmp(hour, dt.hour))
 241                 return c;
 242         if(int c = _cmp(minute, dt.minute))
 243                 return c;
 244         if(int c = _cmp(second, dt.second))
 245                 return c;
 246         if(int c = _cmp(usec, dt.usec))
 247                 return c;
 248         return 0;
 249 }
 250
 251 TimeStamp DateTime::get_timestamp() const
 252 {
 253         if(year<-289701 || year>293641)
 254                 throw range_error("DateTime::get_timestamp");
 255
 256         RawTime raw = (((hour*60LL)+minute)*60+second)*1000000+usec;
 257         int days = (year-1970)*365;
 258         days += (year-1)/4-(year-1)/100+(year-1)/400-477;
 259         for(unsigned i=1; i<month; ++i)
 260                 days += month_days(year, i);
 261         days += mday-1;
 262
 263         raw += days*86400000000LL;
 264
 265         return TimeStamp(raw);
 266 }
 267
 268 string DateTime::format(const string &fmt) const
 269 {
 270         string result;
 271         for(auto i=fmt.begin(); i!=fmt.end(); ++i)
 272         {
 273                 if(*i=='%')
 274                 {
 275                         ++i;
 276                         if(i==fmt.end())
 277                                 break;
 278                         else if(*i=='d')
 279                                 result += Msp::format("%02d", mday);
 280                         else if(*i=='H')
 281                                 result += Msp::format("%02d", hour);
 282                         else if(*i=='I')
 283                                 result += Msp::format("%02d", hour%12);
 284                         else if(*i=='m')
 285                                 result += Msp::format("%02d", month);
 286                         else if(*i=='M')
 287                                 result += Msp::format("%02d", minute);
 288                         else if(*i=='p')
 289                                 result += ((hour>=12) ? "PM" : "AM");
 290                         else if(*i=='S')
 291                                 result += Msp::format("%02d", second);
 292                         else if(*i=='y')
 293                                 result += Msp::format("%02d", year%100);
 294                         else if(*i=='Y')
 295                                 result += Msp::format("%04d", year);
 296                         else if(*i=='%')
 297                                 result += '%';
 298                 }
 299                 else
 300                         result += *i;
 301         }
 302
 303         return result;
 304 }
 305
 306 string DateTime::format_rfc3339() const
 307 {
 308         string result = format("%Y-%m-%dT%H:%M:%S");
 309         if(usec)
 310                 result += Msp::format(".%06d", usec);
 311         if(const TimeDelta &offs = zone.get_offset())
 312         {
 313                 int m = abs(static_cast<int>(offs/Time::min));
 314                 result += Msp::format("%c%02d:%02d", (offs<zero ? '-' : '+'), m/60, m%60);
 315         }
 316         else
 317                 result += 'Z';
 318         return result;
 319 }
 320
 321 void DateTime::add_raw(RawTime raw)
 322 {
 323         int days = static_cast<int>(raw/86400000000LL);
 324         raw %= 86400000000LL;
 325         if(raw<0)
 326         {
 327                 --days;
 328                 raw += 86400000000LL;
 329         }
 330
 331         usec += raw%1000000; raw /= 1000000;
 332         second += raw%60;    raw /= 60;
 333         minute += raw%60;    raw /= 60;
 334         hour += raw%24;      raw /= 24;
 335
 336         add_days(days);
 337         normalize();
 338 }
 339
 340 void DateTime::normalize()
 341 {
 342         second += usec/1000000;
 343         usec %= 1000000;
 344         minute += second/60;
 345         second %= 60;
 346         hour += minute/60;
 347         minute %= 60;
 348         mday += hour/24;
 349         hour %= 24;
 350         while(mday>month_days(year, month))
 351         {
 352                 mday -= month_days(year, month);
 353                 ++month;
 354                 if(month>12)
 355                 {
 356                         ++year;
 357                         month = 1;
 358                 }
 359         }
 360 }
 361
 362 } // namespace Time
 363 } // namespace Msp