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         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 DateTime DateTime::parse_rfc3339(const string &str)
 109 {
 110         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}))$");
 111
 112         RegMatch m = re.match(str);
 113         if(!m)
 114                 throw invalid_argument("DateTime::parse_rfc3339");
 115
 116         unsigned year = lexical_cast<unsigned>(m[1].str);
 117         unsigned month = lexical_cast<unsigned>(m[2].str);
 118         unsigned mday = lexical_cast<unsigned>(m[3].str);
 119         unsigned hr = lexical_cast<unsigned>(m[4].str);
 120         unsigned minute = lexical_cast<unsigned>(m[5].str);
 121         unsigned second = lexical_cast<unsigned>(m[6].str);
 122         unsigned us = 0;
 123         const string &sec_frac = m[8].str;
 124         if(!sec_frac.empty())
 125         {
 126                 us = lexical_cast<unsigned>(sec_frac);
 127                 for(unsigned i=sec_frac.size(); i<6; ++i)
 128                         us *= 10;
 129                 for(unsigned i=sec_frac.size(); i>6; --i)
 130                         us /= 10;
 131         }
 132
 133         DateTime result = DateTime(year, month, mday, hr, minute, second, us);
 134
 135         int tzoff = 0;
 136         if(m[9].str!="Z")
 137         {
 138                 tzoff = lexical_cast<unsigned>(m[10].str)*60+lexical_cast<unsigned>(m[11].str);
 139                 if(m[9].str[0]=='-')
 140                         tzoff = -tzoff;
 141         }
 142
 143         result.set_timezone(tzoff);
 144
 145         return result;
 146 }
 147
 148 void DateTime::add_days(int days)
 149 {
 150         int new_year = year;
 151
 152         /* Leap years have a 400 year cycle, so any 400 consecutive years have a
 153         constant number of days (400*365+97 = 146097) */
 154         new_year += days/146097*400;
 155         days %= 146097;
 156
 157         if(days<0)
 158         {
 159                 new_year -= 400;
 160                 days += 146097;
 161         }
 162
 163         // Fudge factor for leap day
 164         int fudge = (month<=2) ? 1 : 0;
 165
 166         // (Almost) every 4 year cycle has 1 leap year and 3 normal years
 167         unsigned cycles = days/1461;
 168         days %= 1461;
 169
 170         new_year += cycles*4;
 171
 172         // See how many non-leap-years we counted as leap years and reclaim the lost days
 173         // XXX This breaks with negative years
 174         unsigned missed_leap_days = ((year-fudge)%100+cycles*4)/100;
 175         if((year-fudge)%400+cycles*4>=400)
 176                 --missed_leap_days;
 177
 178         days += missed_leap_days;
 179
 180         // Count single years from the 4 year cycle
 181         cycles = days/365;
 182         days %= 365;
 183
 184         new_year += cycles;
 185
 186         if((year-fudge)%4+cycles>=4 && (new_year%100>=4 || new_year%400<4))
 187         {
 188                 // We passed a leap year - decrement days
 189                 if(days==0)
 190                 {
 191                         days = is_leap_year(new_year-fudge) ? 365 : 364;
 192                         --new_year;
 193                 }
 194                 else
 195                         --days;
 196         }
 197
 198         year = new_year;
 199
 200         // Step months
 201         while(mday+days>month_days(year, month))
 202         {
 203                 days -= month_days(year, month);
 204                 ++month;
 205                 if(month>12)
 206                 {
 207                         ++year;
 208                         month = 1;
 209                 }
 210         }
 211
 212         mday += days;
 213 }
 214
 215 void DateTime::set_timezone(const TimeZone &tz)
 216 {
 217         zone = tz;
 218 }
 219
 220 void DateTime::convert_timezone(const TimeZone &tz)
 221 {
 222         add_raw((tz.get_offset()-zone.get_offset()).raw());
 223         zone = tz;
 224 }
 225
 226 DateTime DateTime::operator+(const TimeDelta &td) const
 227 {
 228         DateTime dt(*this);
 229         dt.add_raw(td.raw());
 230         return dt;
 231 }
 232
 233 DateTime &DateTime::operator+=(const TimeDelta &td)
 234 {
 235         add_raw(td.raw());
 236         return *this;
 237 }
 238
 239 DateTime DateTime::operator-(const TimeDelta &td) const
 240 {
 241         DateTime dt(*this);
 242         dt.add_raw(-td.raw());
 243         return dt;
 244 }
 245
 246 DateTime &DateTime::operator-=(const TimeDelta &td)
 247 {
 248         add_raw(-td.raw());
 249         return *this;
 250 }
 251
 252 int DateTime::cmp(const DateTime &dt) const
 253 {
 254         if(int c = cmp_(year, dt.year))
 255                 return c;
 256         if(int c = cmp_(month, dt.month))
 257                 return c;
 258         if(int c = cmp_(mday, dt.mday))
 259                 return c;
 260         if(int c = cmp_(hour, dt.hour))
 261                 return c;
 262         if(int c = cmp_(minute, dt.minute))
 263                 return c;
 264         if(int c = cmp_(second, dt.second))
 265                 return c;
 266         if(int c = cmp_(usec, dt.usec))
 267                 return c;
 268         return 0;
 269 }
 270
 271 TimeStamp DateTime::get_timestamp() const
 272 {
 273         if(year<-289701 || year>293641)
 274                 throw range_error("DateTime::get_timestamp");
 275
 276         RawTime raw = (((hour*60LL)+minute)*60+second)*1000000+usec;
 277         int days = (year-1970)*365;
 278         days += (year-1)/4-(year-1)/100+(year-1)/400-477;
 279         for(unsigned i=1; i<month; ++i)
 280                 days += month_days(year, i);
 281         days += mday-1;
 282
 283         raw += days*86400000000LL;
 284
 285         return TimeStamp(raw);
 286 }
 287
 288 string DateTime::format(const string &fmt) const
 289 {
 290         string result;
 291         for(string::const_iterator i=fmt.begin(); i!=fmt.end(); ++i)
 292         {
 293                 if(*i=='%')
 294                 {
 295                         ++i;
 296                         if(i==fmt.end())
 297                                 break;
 298                         else if(*i=='d')
 299                                 result += Msp::format("%02d", mday);
 300                         else if(*i=='H')
 301                                 result += Msp::format("%02d", hour);
 302                         else if(*i=='I')
 303                                 result += Msp::format("%02d", hour%12);
 304                         else if(*i=='m')
 305                                 result += Msp::format("%02d", month);
 306                         else if(*i=='M')
 307                                 result += Msp::format("%02d", minute);
 308                         else if(*i=='p')
 309                                 result += ((hour>=12) ? "PM" : "AM");
 310                         else if(*i=='S')
 311                                 result += Msp::format("%02d", second);
 312                         else if(*i=='y')
 313                                 result += Msp::format("%02d", year%100);
 314                         else if(*i=='Y')
 315                                 result += Msp::format("%04d", year);
 316                         else if(*i=='%')
 317                                 result += '%';
 318                 }
 319                 else
 320                         result += *i;
 321         }
 322
 323         return result;
 324 }
 325
 326 string DateTime::format_rfc3339() const
 327 {
 328         string result = format("%Y-%m-%dT%H:%M:%S");
 329         if(usec)
 330                 result += Msp::format(".%06d", usec);
 331         if(const TimeDelta &offs = zone.get_offset())
 332         {
 333                 int m = abs(static_cast<int>(offs/Time::min));
 334                 result += Msp::format("%c%02d:%02d", (offs<zero ? '-' : '+'), m/60, m%60);
 335         }
 336         else
 337                 result += 'Z';
 338         return result;
 339 }
 340
 341 void DateTime::add_raw(RawTime raw)
 342 {
 343         int days = static_cast<int>(raw/86400000000LL);
 344         raw %= 86400000000LL;
 345         if(raw<0)
 346         {
 347                 --days;
 348                 raw += 86400000000LL;
 349         }
 350
 351         usec += raw%1000000; raw /= 1000000;
 352         second += raw%60;    raw /= 60;
 353         minute += raw%60;    raw /= 60;
 354         hour += raw%24;      raw /= 24;
 355
 356         add_days(days);
 357         normalize();
 358 }
 359
 360 void DateTime::normalize()
 361 {
 362         second += usec/1000000;
 363         usec %= 1000000;
 364         minute += second/60;
 365         second %= 60;
 366         hour += minute/60;
 367         minute %= 60;
 368         mday += hour/24;
 369         hour %= 24;
 370         while(mday>month_days(year, month))
 371         {
 372                 mday -= month_days(year, month);
 373                 ++month;
 374                 if(month>12)
 375                 {
 376                         ++year;
 377                         month = 1;
 378                 }
 379         }
 380 }
 381
 382 } // namespace Time
 383 } // namespace Msp