source/time/datetime.cpp

   1 #include <cstdlib>
   2 #include <stdexcept>
   3 #include <msp/strings/format.h>
   4 #include "datetime.h"
   5 #include "timestamp.h"
   6 #include "units.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         init(ts);
  49 }
  50
  51 DateTime::DateTime(const TimeStamp &ts, const TimeZone &tz)
  52 {
  53         init(ts);
  54         convert_timezone(tz);
  55 }
  56
  57 DateTime::DateTime(int y, unsigned char m, unsigned char d)
  58 {
  59         init(y, m, d, 0, 0, 0, 0);
  60 }
  61
  62 DateTime::DateTime(int y, unsigned char m, unsigned char d, unsigned char h, unsigned char n, unsigned char s)
  63 {
  64         init(y, m, d, h, n, s, 0);
  65 }
  66
  67 DateTime::DateTime(int y, unsigned char m, unsigned char d, unsigned char h, unsigned char n, unsigned char s, unsigned u)
  68 {
  69         init(y, m, d, h, n, s, u);
  70 }
  71
  72 void DateTime::init(const TimeStamp &ts)
  73 {
  74         year = 1970;
  75         month = 1;
  76         mday = 1;
  77         hour = 0;
  78         minute = 0;
  79         second = 0;
  80         usec = 0;
  81         add_raw(ts.raw());
  82 }
  83
  84 void DateTime::init(int y, unsigned char m, unsigned char d, unsigned char h, unsigned char n, unsigned char s, unsigned u)
  85 {
  86         year = y;
  87         month = m;
  88         mday = d;
  89         hour = h;
  90         minute = n;
  91         second = s;
  92         usec = u;
  93
  94         if(usec>=1000000)
  95                 throw out_of_range("DateTime::DateTime usec");
  96         if(second>=60)
  97                 throw out_of_range("DateTime::DateTime second");
  98         if(minute>=60)
  99                 throw out_of_range("DateTime::DateTime minute");
 100         if(hour>=24)
 101                 throw out_of_range("DateTime::DateTime hour");
 102         if(month<1 || month>12)
 103                 throw out_of_range("DateTime::DateTime month");
 104         if(mday<1 || mday>month_days(year, month))
 105                 throw out_of_range("DateTime::DateTime mday");
 106 }
 107
 108 void DateTime::add_days(int days)
 109 {
 110         int new_year = year;
 111
 112         /* Leap years have a 400 year cycle, so any 400 consecutive years have a
 113         constant number of days (400*365+97 = 146097) */
 114         new_year += days/146097*400;
 115         days %= 146097;
 116
 117         if(days<0)
 118         {
 119                 new_year -= 400;
 120                 days += 146097;
 121         }
 122
 123         // Fudge factor for leap day
 124         int fudge = (month<=2)?1:0;
 125
 126         // (Almost) every 4 year cycle has 1 leap year and 3 normal years
 127         unsigned cycles = days/1461;
 128         days %= 1461;
 129
 130         new_year += cycles*4;
 131
 132         // See how many non-leap-years we counted as leap years and reclaim the lost days
 133         // XXX This breaks with negative years
 134         unsigned missed_leap_days = ((year-fudge)%100+cycles*4)/100;
 135         if((year-fudge)%400+cycles*4>=400)
 136                 --missed_leap_days;
 137
 138         days += missed_leap_days;
 139
 140         // Count single years from the 4 year cycle
 141         cycles = days/365;
 142         days %= 365;
 143
 144         new_year += cycles;
 145
 146         if((year-fudge)%4+cycles>=4 && (new_year%100>=4 || new_year%400<4))
 147         {
 148                 // We passed a leap year - decrement days
 149                 if(days==0)
 150                 {
 151                         days = is_leap_year(new_year-fudge)?365:364;
 152                         --new_year;
 153                 }
 154                 else
 155                         --days;
 156         }
 157
 158         year = new_year;
 159
 160         // Step months
 161         while(mday+days>month_days(year, month))
 162         {
 163                 days -= month_days(year, month);
 164                 ++month;
 165                 if(month>12)
 166                 {
 167                         ++year;
 168                         month = 1;
 169                 }
 170         }
 171
 172         mday += days;
 173 }
 174
 175 void DateTime::set_timezone(const TimeZone &tz)
 176 {
 177         zone = tz;
 178 }
 179
 180 void DateTime::convert_timezone(const TimeZone &tz)
 181 {
 182         add_raw((tz.get_offset()-zone.get_offset()).raw());
 183         zone = tz;
 184 }
 185
 186 DateTime DateTime::operator+(const TimeDelta &td) const
 187 {
 188         DateTime dt(*this);
 189         dt.add_raw(td.raw());
 190         return dt;
 191 }
 192
 193 DateTime &DateTime::operator+=(const TimeDelta &td)
 194 {
 195         add_raw(td.raw());
 196         return *this;
 197 }
 198
 199 DateTime DateTime::operator-(const TimeDelta &td) const
 200 {
 201         DateTime dt(*this);
 202         dt.add_raw(-td.raw());
 203         return dt;
 204 }
 205
 206 DateTime &DateTime::operator-=(const TimeDelta &td)
 207 {
 208         add_raw(-td.raw());
 209         return *this;
 210 }
 211
 212 int DateTime::cmp(const DateTime &dt) const
 213 {
 214         if(int c = cmp_(year, dt.year))
 215                 return c;
 216         if(int c = cmp_(month, dt.month))
 217                 return c;
 218         if(int c = cmp_(mday, dt.mday))
 219                 return c;
 220         if(int c = cmp_(hour, dt.hour))
 221                 return c;
 222         if(int c = cmp_(minute, dt.minute))
 223                 return c;
 224         if(int c = cmp_(second, dt.second))
 225                 return c;
 226         if(int c = cmp_(usec, dt.usec))
 227                 return c;
 228         return 0;
 229 }
 230
 231 TimeStamp DateTime::get_timestamp() const
 232 {
 233         if(year<-289701 || year>293641)
 234                 throw range_error("DateTime::get_timestamp");
 235
 236         RawTime raw = (((hour*60LL)+minute)*60+second)*1000000+usec;
 237         int days = (year-1970)*365;
 238         days += (year-1)/4-(year-1)/100+(year-1)/400-477;
 239         for(unsigned i=1; i<month; ++i)
 240                 days += month_days(year, i);
 241         days += mday-1;
 242
 243         raw += days*86400000000LL;
 244
 245         return TimeStamp(raw);
 246 }
 247
 248 string DateTime::format(const string &fmt) const
 249 {
 250         string result;
 251         for(string::const_iterator i=fmt.begin(); i!=fmt.end(); ++i)
 252         {
 253                 if(*i=='%')
 254                 {
 255                         ++i;
 256                         if(i==fmt.end())
 257                                 break;
 258                         else if(*i=='d')
 259                                 result += Msp::format("%02d", mday);
 260                         else if(*i=='H')
 261                                 result += Msp::format("%02d", hour);
 262                         else if(*i=='I')
 263                                 result += Msp::format("%02d", hour%12);
 264                         else if(*i=='m')
 265                                 result += Msp::format("%02d", month);
 266                         else if(*i=='M')
 267                                 result += Msp::format("%02d", minute);
 268                         else if(*i=='p')
 269                                 result += ((hour>=12) ? "PM" : "AM");
 270                         else if(*i=='S')
 271                                 result += Msp::format("%02d", second);
 272                         else if(*i=='y')
 273                                 result += Msp::format("%02d", year%100);
 274                         else if(*i=='Y')
 275                                 result += Msp::format("%04d", year);
 276                         else if(*i=='%')
 277                                 result += '%';
 278                 }
 279                 else
 280                         result += *i;
 281         }
 282
 283         return result;
 284 }
 285
 286 string DateTime::format_rfc3339() const
 287 {
 288         string result = format("%Y-%m-%dT%H:%M:%S");
 289         if(const TimeDelta &offs = zone.get_offset())
 290         {
 291                 int m = abs(static_cast<int>(offs/Time::min));
 292                 result += Msp::format("%c%02d:%02d", (offs<zero ? '-' : '+'), m/60, m%60);
 293         }
 294         else
 295                 result += 'Z';
 296         return result;
 297 }
 298
 299 void DateTime::add_raw(RawTime raw)
 300 {
 301         int days = static_cast<int>(raw/86400000000LL);
 302         raw %= 86400000000LL;
 303         if(raw<0)
 304         {
 305                 --days;
 306                 raw += 86400000000LL;
 307         }
 308
 309         usec+=raw%1000000; raw /= 1000000;
 310         second+=raw%60;    raw /= 60;
 311         minute+=raw%60;    raw /= 60;
 312         hour+=raw%24;      raw /= 24;
 313
 314         add_days(days);
 315         normalize();
 316 }
 317
 318 void DateTime::normalize()
 319 {
 320         second += usec/1000000;
 321         usec %= 1000000;
 322         minute += second/60;
 323         second %= 60;
 324         hour += minute/60;
 325         minute %= 60;
 326         mday += hour/24;
 327         hour %= 24;
 328         while(mday>month_days(year, month))
 329         {
 330                 mday -= month_days(year, month);
 331                 ++month;
 332                 if(month>12)
 333                 {
 334                         ++year;
 335                         month = 1;
 336                 }
 337         }
 338 }
 339
 340 } // namespace Time
 341 } // namespace Msp