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})(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
 123         DateTime result = DateTime(year, month, mday, hr, minute, second);
 124
 125         int tzoff = 0;
 126         if(m[7].str!="Z")
 127         {
 128                 tzoff = lexical_cast<unsigned>(m[8].str)*60+lexical_cast<unsigned>(m[9].str);
 129                 if(m[7].str[0]=='-')
 130                         tzoff = -tzoff;
 131         }
 132
 133         result.set_timezone(tzoff);
 134
 135         return result;
 136 }
 137
 138 void DateTime::add_days(int days)
 139 {
 140         int new_year = year;
 141
 142         /* Leap years have a 400 year cycle, so any 400 consecutive years have a
 143         constant number of days (400*365+97 = 146097) */
 144         new_year += days/146097*400;
 145         days %= 146097;
 146
 147         if(days<0)
 148         {
 149                 new_year -= 400;
 150                 days += 146097;
 151         }
 152
 153         // Fudge factor for leap day
 154         int fudge = (month<=2) ? 1 : 0;
 155
 156         // (Almost) every 4 year cycle has 1 leap year and 3 normal years
 157         unsigned cycles = days/1461;
 158         days %= 1461;
 159
 160         new_year += cycles*4;
 161
 162         // See how many non-leap-years we counted as leap years and reclaim the lost days
 163         // XXX This breaks with negative years
 164         unsigned missed_leap_days = ((year-fudge)%100+cycles*4)/100;
 165         if((year-fudge)%400+cycles*4>=400)
 166                 --missed_leap_days;
 167
 168         days += missed_leap_days;
 169
 170         // Count single years from the 4 year cycle
 171         cycles = days/365;
 172         days %= 365;
 173
 174         new_year += cycles;
 175
 176         if((year-fudge)%4+cycles>=4 && (new_year%100>=4 || new_year%400<4))
 177         {
 178                 // We passed a leap year - decrement days
 179                 if(days==0)
 180                 {
 181                         days = is_leap_year(new_year-fudge) ? 365 : 364;
 182                         --new_year;
 183                 }
 184                 else
 185                         --days;
 186         }
 187
 188         year = new_year;
 189
 190         // Step months
 191         while(mday+days>month_days(year, month))
 192         {
 193                 days -= month_days(year, month);
 194                 ++month;
 195                 if(month>12)
 196                 {
 197                         ++year;
 198                         month = 1;
 199                 }
 200         }
 201
 202         mday += days;
 203 }
 204
 205 void DateTime::set_timezone(const TimeZone &tz)
 206 {
 207         zone = tz;
 208 }
 209
 210 void DateTime::convert_timezone(const TimeZone &tz)
 211 {
 212         add_raw((tz.get_offset()-zone.get_offset()).raw());
 213         zone = tz;
 214 }
 215
 216 DateTime DateTime::operator+(const TimeDelta &td) const
 217 {
 218         DateTime dt(*this);
 219         dt.add_raw(td.raw());
 220         return dt;
 221 }
 222
 223 DateTime &DateTime::operator+=(const TimeDelta &td)
 224 {
 225         add_raw(td.raw());
 226         return *this;
 227 }
 228
 229 DateTime DateTime::operator-(const TimeDelta &td) const
 230 {
 231         DateTime dt(*this);
 232         dt.add_raw(-td.raw());
 233         return dt;
 234 }
 235
 236 DateTime &DateTime::operator-=(const TimeDelta &td)
 237 {
 238         add_raw(-td.raw());
 239         return *this;
 240 }
 241
 242 int DateTime::cmp(const DateTime &dt) const
 243 {
 244         if(int c = cmp_(year, dt.year))
 245                 return c;
 246         if(int c = cmp_(month, dt.month))
 247                 return c;
 248         if(int c = cmp_(mday, dt.mday))
 249                 return c;
 250         if(int c = cmp_(hour, dt.hour))
 251                 return c;
 252         if(int c = cmp_(minute, dt.minute))
 253                 return c;
 254         if(int c = cmp_(second, dt.second))
 255                 return c;
 256         if(int c = cmp_(usec, dt.usec))
 257                 return c;
 258         return 0;
 259 }
 260
 261 TimeStamp DateTime::get_timestamp() const
 262 {
 263         if(year<-289701 || year>293641)
 264                 throw range_error("DateTime::get_timestamp");
 265
 266         RawTime raw = (((hour*60LL)+minute)*60+second)*1000000+usec;
 267         int days = (year-1970)*365;
 268         days += (year-1)/4-(year-1)/100+(year-1)/400-477;
 269         for(unsigned i=1; i<month; ++i)
 270                 days += month_days(year, i);
 271         days += mday-1;
 272
 273         raw += days*86400000000LL;
 274
 275         return TimeStamp(raw);
 276 }
 277
 278 string DateTime::format(const string &fmt) const
 279 {
 280         string result;
 281         for(string::const_iterator i=fmt.begin(); i!=fmt.end(); ++i)
 282         {
 283                 if(*i=='%')
 284                 {
 285                         ++i;
 286                         if(i==fmt.end())
 287                                 break;
 288                         else if(*i=='d')
 289                                 result += Msp::format("%02d", mday);
 290                         else if(*i=='H')
 291                                 result += Msp::format("%02d", hour);
 292                         else if(*i=='I')
 293                                 result += Msp::format("%02d", hour%12);
 294                         else if(*i=='m')
 295                                 result += Msp::format("%02d", month);
 296                         else if(*i=='M')
 297                                 result += Msp::format("%02d", minute);
 298                         else if(*i=='p')
 299                                 result += ((hour>=12) ? "PM" : "AM");
 300                         else if(*i=='S')
 301                                 result += Msp::format("%02d", second);
 302                         else if(*i=='y')
 303                                 result += Msp::format("%02d", year%100);
 304                         else if(*i=='Y')
 305                                 result += Msp::format("%04d", year);
 306                         else if(*i=='%')
 307                                 result += '%';
 308                 }
 309                 else
 310                         result += *i;
 311         }
 312
 313         return result;
 314 }
 315
 316 string DateTime::format_rfc3339() const
 317 {
 318         string result = format("%Y-%m-%dT%H:%M:%S");
 319         if(const TimeDelta &offs = zone.get_offset())
 320         {
 321                 int m = abs(static_cast<int>(offs/Time::min));
 322                 result += Msp::format("%c%02d:%02d", (offs<zero ? '-' : '+'), m/60, m%60);
 323         }
 324         else
 325                 result += 'Z';
 326         return result;
 327 }
 328
 329 void DateTime::add_raw(RawTime raw)
 330 {
 331         int days = static_cast<int>(raw/86400000000LL);
 332         raw %= 86400000000LL;
 333         if(raw<0)
 334         {
 335                 --days;
 336                 raw += 86400000000LL;
 337         }
 338
 339         usec += raw%1000000; raw /= 1000000;
 340         second += raw%60;    raw /= 60;
 341         minute += raw%60;    raw /= 60;
 342         hour += raw%24;      raw /= 24;
 343
 344         add_days(days);
 345         normalize();
 346 }
 347
 348 void DateTime::normalize()
 349 {
 350         second += usec/1000000;
 351         usec %= 1000000;
 352         minute += second/60;
 353         second %= 60;
 354         hour += minute/60;
 355         minute %= 60;
 356         mday += hour/24;
 357         hour %= 24;
 358         while(mday>month_days(year, month))
 359         {
 360                 mday -= month_days(year, month);
 361                 ++month;
 362                 if(month>12)
 363                 {
 364                         ++year;
 365                         month = 1;
 366                 }
 367         }
 368 }
 369
 370 } // namespace Time
 371 } // namespace Msp