source/time/datetime.cpp

   1 /* $Id$ */
   2 #include <sstream>
   3 #include <iomanip>
   4 #include "../core/except.h"
   5 #include "datetime.h"
   6 #include "timestamp.h"
   7
   8 using namespace std;
   9
  10 namespace {
  11
  12 inline bool is_leap_year(int32_t y)
  13 { return y%4==0 && (y%100 || y%400==0); }
  14
  15 inline uint8_t month_days(int32_t y, uint8_t 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         year(1970),
  48         month(1),
  49         mday(1),
  50         hour(0),
  51         minute(0),
  52         second(0),
  53         usec(0)
  54 {
  55         add_raw(ts.raw());
  56 }
  57
  58 DateTime::DateTime(int32_t y, uint8_t m, uint8_t d):
  59         year(y),
  60         month(m),
  61         mday(d),
  62         hour(0),
  63         minute(0),
  64         second(0),
  65         usec(0)
  66 { }
  67
  68 DateTime::DateTime(int32_t y, uint8_t m, uint8_t d, uint8_t h, uint8_t n, uint8_t s):
  69         year(y),
  70         month(m),
  71         mday(d),
  72         hour(h),
  73         minute(n),
  74         second(s),
  75         usec(0)
  76 { }
  77
  78 DateTime::DateTime(int32_t y, uint8_t m, uint8_t d, uint8_t h, uint8_t n, uint8_t s, uint32_t u):
  79         year(y),
  80         month(m),
  81         mday(d),
  82         hour(h),
  83         minute(n),
  84         second(s),
  85         usec(u)
  86 { }
  87
  88 void DateTime::add_days(int32_t days)
  89 {
  90         unsigned new_year=year;
  91
  92         /* Leap years have a 400 year cycle, so any 400 consecutive years have a
  93         constant number of days (400*365+97=146097) */
  94         new_year+=days/146097*400;
  95         days%=146097;
  96
  97         if(days<0)
  98         {
  99                 new_year-=400;
 100                 days+=146097;
 101         }
 102
 103         // Fudge factor for leap day
 104         int fudge=(month<=2)?1:0;
 105
 106         // (Almost) every 4 year cycle has 1 leap year and 3 normal years
 107         unsigned cycles=days/1461;
 108         days%=1461;
 109
 110         new_year+=cycles*4;
 111
 112         // See how many non-leap-years we counted as leap years and reclaim the lost days
 113         unsigned missed_leap_days=((year-fudge)%100+cycles*4)/100;
 114         if((year-fudge)%400+cycles*4>=400)
 115                 --missed_leap_days;
 116
 117         days+=missed_leap_days;
 118
 119         // Count single years from the 4 year cycle
 120         cycles=days/365;
 121         days%=365;
 122
 123         new_year+=cycles;
 124
 125         if((year-fudge)%4+cycles>=4)
 126         {
 127                 // We passed a leap year - decrement days
 128                 if(days==0)
 129                 {
 130                         --new_year;
 131                         days=is_leap_year(new_year)?365:364;
 132                 }
 133                 else
 134                         --days;
 135         }
 136
 137         year=new_year;
 138
 139         // Step months
 140         while(mday+days>month_days(year, month))
 141         {
 142                 days-=month_days(year, month);
 143                 ++month;
 144                 if(month>12)
 145                 {
 146                         ++year;
 147                         month=1;
 148                 }
 149         }
 150
 151         mday+=days;
 152 }
 153
 154 DateTime DateTime::operator+(const TimeDelta &td) const
 155 {
 156         DateTime dt(*this);
 157         dt.add_raw(td.raw());
 158         return dt;
 159 }
 160
 161 DateTime &DateTime::operator+=(const TimeDelta &td)
 162 {
 163         add_raw(td.raw());
 164         return *this;
 165 }
 166
 167 int DateTime::cmp(const DateTime &dt) const
 168 {
 169         if(int c=cmp_(year, dt.year))
 170                 return c;
 171         if(int c=cmp_(month, dt.month))
 172                 return c;
 173         if(int c=cmp_(mday, dt.mday))
 174                 return c;
 175         if(int c=cmp_(hour, dt.hour))
 176                 return c;
 177         if(int c=cmp_(minute, dt.minute))
 178                 return c;
 179         if(int c=cmp_(second, dt.second))
 180                 return c;
 181         if(int c=cmp_(usec, dt.usec))
 182                 return c;
 183         return 0;
 184 }
 185
 186 TimeStamp DateTime::get_timestamp() const
 187 {
 188         if(year<-289701 || year>293641)
 189                 throw Exception("DateTime is not representable as a TimeStamp");
 190
 191         int64_t raw=(((hour*60LL)+minute)*60+second)*1000000+usec;
 192         int days=(year-1970)*365;
 193         days+=(year-1)/4-(year-1)/100+(year-1)/400-477;
 194         for(unsigned i=1; i<month; ++i)
 195                 days+=month_days(year, i);
 196         days+=mday-1;
 197
 198         raw+=days*86400000000LL;
 199
 200         return TimeStamp(raw);
 201 }
 202
 203 string DateTime::format(const string &fmt) const
 204 {
 205         ostringstream ss;
 206         ss.fill('0');
 207         for(string::const_iterator i=fmt.begin(); i!=fmt.end(); ++i)
 208         {
 209                 if(*i=='%')
 210                 {
 211                         ++i;
 212                         if(i==fmt.end())
 213                                 break;
 214                         else if(*i=='d')
 215                                 ss<<setw(2)<<int(mday);
 216                         else if(*i=='H')
 217                                 ss<<setw(2)<<int(hour);
 218                         else if(*i=='I')
 219                                 ss<<setw(2)<<hour%12;
 220                         else if(*i=='m')
 221                                 ss<<setw(2)<<int(month);
 222                         else if(*i=='M')
 223                                 ss<<setw(2)<<int(minute);
 224                         else if(*i=='p')
 225                                 ss<<((hour>=12) ? "PM" : "AM");
 226                         else if(*i=='S')
 227                                 ss<<setw(2)<<int(second);
 228                         else if(*i=='y')
 229                                 ss<<setw(2)<<year%100;
 230                         else if(*i=='Y')
 231                                 ss<<year;
 232                         else if(*i=='%')
 233                                 ss<<'%';
 234                 }
 235                 else
 236                         ss<<*i;
 237         }
 238
 239         return ss.str();
 240 }
 241
 242 void DateTime::add_raw(int64_t raw)
 243 {
 244         int32_t days=raw/86400000000LL;
 245         raw%=86400000000LL;
 246         if(raw<0)
 247         {
 248                 ++days;
 249                 raw+=86400000000LL;
 250         }
 251
 252         usec+=raw%1000000; raw/=1000000;
 253         second+=raw%60;    raw/=60;
 254         minute+=raw%60;    raw/=60;
 255         hour+=raw%24;      raw/=24;
 256
 257         add_days(days);
 258         normalize();
 259 }
 260
 261 void DateTime::normalize()
 262 {
 263         second+=usec/1000000;
 264         usec%=1000000;
 265         minute+=second/60;
 266         second%=60;
 267         hour+=minute/60;
 268         minute%=60;
 269         mday+=hour/24;
 270         hour%=24;
 271         while(mday>month_days(year, month))
 272         {
 273                 mday-=month_days(year, month);
 274                 ++month;
 275                 if(month>12)
 276                 {
 277                         ++year;
 278                         month=1;
 279                 }
 280         }
 281 }
 282
 283 } // namespace Time
 284 } // namespace Msp