/* ** 2003 October 31 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This file contains the C functions that implement date and time ** functions for SQLite. ** ** There is only one exported symbol in this file - the function ** sqlite3RegisterDateTimeFunctions() found at the bottom of the file. ** All other code has file scope. ** ** $Id: date.c,v 1.1.1.1 2006/02/03 20:35:11 hoganrobert Exp $ ** ** NOTES: ** ** SQLite processes all times and dates as Julian Day numbers. The ** dates and times are stored as the number of days since noon ** in Greenwich on November 24, 4714 B.C. according to the Gregorian ** calendar system. ** ** 1970-01-01 00:00:00 is JD 2440587.5 ** 2000-01-01 00:00:00 is JD 2451544.5 ** ** This implemention requires years to be expressed as a 4-digit number ** which means that only dates between 0000-01-01 and 9999-12-31 can ** be represented, even though julian day numbers allow a much wider ** range of dates. ** ** The Gregorian calendar system is used for all dates and times, ** even those that predate the Gregorian calendar. Historians usually ** use the Julian calendar for dates prior to 1582-10-15 and for some ** dates afterwards, depending on locale. Beware of this difference. ** ** The conversion algorithms are implemented based on descriptions ** in the following text: ** ** Jean Meeus ** Astronomical Algorithms, 2nd Edition, 1998 ** ISBM 0-943396-61-1 ** Willmann-Bell, Inc ** Richmond, Virginia (USA) */ #include "sqliteInt.h" #include "os.h" #include #include #include #include #ifndef SQLITE_OMIT_DATETIME_FUNCS /* ** A structure for holding a single date and time. */ typedef struct DateTime DateTime; struct DateTime { double rJD; /* The julian day number */ int Y, M, D; /* Year, month, and day */ int h, m; /* Hour and minutes */ int tz; /* Timezone offset in minutes */ double s; /* Seconds */ char validYMD; /* True if Y,M,D are valid */ char validHMS; /* True if h,m,s are valid */ char validJD; /* True if rJD is valid */ char validTZ; /* True if tz is valid */ }; /* ** Convert zDate into one or more integers. Additional arguments ** come in groups of 5 as follows: ** ** N number of digits in the integer ** min minimum allowed value of the integer ** max maximum allowed value of the integer ** nextC first character after the integer ** pVal where to write the integers value. ** ** Conversions continue until one with nextC==0 is encountered. ** The function returns the number of successful conversions. */ static int getDigits(const char *zDate, ...){ va_list ap; int val; int N; int min; int max; int nextC; int *pVal; int cnt = 0; va_start(ap, zDate); do{ N = va_arg(ap, int); min = va_arg(ap, int); max = va_arg(ap, int); nextC = va_arg(ap, int); pVal = va_arg(ap, int*); val = 0; while( N-- ){ if( !isdigit(*(u8*)zDate) ){ return cnt; } val = val*10 + *zDate - '0'; zDate++; } if( valmax || (nextC!=0 && nextC!=*zDate) ){ return cnt; } *pVal = val; zDate++; cnt++; }while( nextC ); return cnt; } /* ** Read text from z[] and convert into a floating point number. Return ** the number of digits converted. */ static int getValue(const char *z, double *pR){ const char *zEnd; *pR = sqlite3AtoF(z, &zEnd); return zEnd - z; } /* ** Parse a timezone extension on the end of a date-time. ** The extension is of the form: ** ** (+/-)HH:MM ** ** If the parse is successful, write the number of minutes ** of change in *pnMin and return 0. If a parser error occurs, ** return 0. ** ** A missing specifier is not considered an error. */ static int parseTimezone(const char *zDate, DateTime *p){ int sgn = 0; int nHr, nMn; while( isspace(*(u8*)zDate) ){ zDate++; } p->tz = 0; if( *zDate=='-' ){ sgn = -1; }else if( *zDate=='+' ){ sgn = +1; }else{ return *zDate!=0; } zDate++; if( getDigits(zDate, 2, 0, 14, ':', &nHr, 2, 0, 59, 0, &nMn)!=2 ){ return 1; } zDate += 5; p->tz = sgn*(nMn + nHr*60); while( isspace(*(u8*)zDate) ){ zDate++; } return *zDate!=0; } /* ** Parse times of the form HH:MM or HH:MM:SS or HH:MM:SS.FFFF. ** The HH, MM, and SS must each be exactly 2 digits. The ** fractional seconds FFFF can be one or more digits. ** ** Return 1 if there is a parsing error and 0 on success. */ static int parseHhMmSs(const char *zDate, DateTime *p){ int h, m, s; double ms = 0.0; if( getDigits(zDate, 2, 0, 24, ':', &h, 2, 0, 59, 0, &m)!=2 ){ return 1; } zDate += 5; if( *zDate==':' ){ zDate++; if( getDigits(zDate, 2, 0, 59, 0, &s)!=1 ){ return 1; } zDate += 2; if( *zDate=='.' && isdigit((u8)zDate[1]) ){ double rScale = 1.0; zDate++; while( isdigit(*(u8*)zDate) ){ ms = ms*10.0 + *zDate - '0'; rScale *= 10.0; zDate++; } ms /= rScale; } }else{ s = 0; } p->validJD = 0; p->validHMS = 1; p->h = h; p->m = m; p->s = s + ms; if( parseTimezone(zDate, p) ) return 1; p->validTZ = p->tz!=0; return 0; } /* ** Convert from YYYY-MM-DD HH:MM:SS to julian day. We always assume ** that the YYYY-MM-DD is according to the Gregorian calendar. ** ** Reference: Meeus page 61 */ static void computeJD(DateTime *p){ int Y, M, D, A, B, X1, X2; if( p->validJD ) return; if( p->validYMD ){ Y = p->Y; M = p->M; D = p->D; }else{ Y = 2000; /* If no YMD specified, assume 2000-Jan-01 */ M = 1; D = 1; } if( M<=2 ){ Y--; M += 12; } A = Y/100; B = 2 - A + (A/4); X1 = 365.25*(Y+4716); X2 = 30.6001*(M+1); p->rJD = X1 + X2 + D + B - 1524.5; p->validJD = 1; p->validYMD = 0; if( p->validHMS ){ p->rJD += (p->h*3600.0 + p->m*60.0 + p->s)/86400.0; if( p->validTZ ){ p->rJD += p->tz*60/86400.0; p->validHMS = 0; p->validTZ = 0; } } } /* ** Parse dates of the form ** ** YYYY-MM-DD HH:MM:SS.FFF ** YYYY-MM-DD HH:MM:SS ** YYYY-MM-DD HH:MM ** YYYY-MM-DD ** ** Write the result into the DateTime structure and return 0 ** on success and 1 if the input string is not a well-formed ** date. */ static int parseYyyyMmDd(const char *zDate, DateTime *p){ int Y, M, D, neg; if( zDate[0]=='-' ){ zDate++; neg = 1; }else{ neg = 0; } if( getDigits(zDate,4,0,9999,'-',&Y,2,1,12,'-',&M,2,1,31,0,&D)!=3 ){ return 1; } zDate += 10; while( isspace(*(u8*)zDate) || 'T'==*(u8*)zDate ){ zDate++; } if( parseHhMmSs(zDate, p)==0 ){ /* We got the time */ }else if( *zDate==0 ){ p->validHMS = 0; }else{ return 1; } p->validJD = 0; p->validYMD = 1; p->Y = neg ? -Y : Y; p->M = M; p->D = D; if( p->validTZ ){ computeJD(p); } return 0; } /* ** Attempt to parse the given string into a Julian Day Number. Return ** the number of errors. ** ** The following are acceptable forms for the input string: ** ** YYYY-MM-DD HH:MM:SS.FFF +/-HH:MM ** DDDD.DD ** now ** ** In the first form, the +/-HH:MM is always optional. The fractional ** seconds extension (the ".FFF") is optional. The seconds portion ** (":SS.FFF") is option. The year and date can be omitted as long ** as there is a time string. The time string can be omitted as long ** as there is a year and date. */ static int parseDateOrTime(const char *zDate, DateTime *p){ memset(p, 0, sizeof(*p)); if( parseYyyyMmDd(zDate,p)==0 ){ return 0; }else if( parseHhMmSs(zDate, p)==0 ){ return 0; }else if( sqlite3StrICmp(zDate,"now")==0){ double r; sqlite3OsCurrentTime(&r); p->rJD = r; p->validJD = 1; return 0; }else if( sqlite3IsNumber(zDate, 0, SQLITE_UTF8) ){ p->rJD = sqlite3AtoF(zDate, 0); p->validJD = 1; return 0; } return 1; } /* ** Compute the Year, Month, and Day from the julian day number. */ static void computeYMD(DateTime *p){ int Z, A, B, C, D, E, X1; if( p->validYMD ) return; if( !p->validJD ){ p->Y = 2000; p->M = 1; p->D = 1; }else{ Z = p->rJD + 0.5; A = (Z - 1867216.25)/36524.25; A = Z + 1 + A - (A/4); B = A + 1524; C = (B - 122.1)/365.25; D = 365.25*C; E = (B-D)/30.6001; X1 = 30.6001*E; p->D = B - D - X1; p->M = E<14 ? E-1 : E-13; p->Y = p->M>2 ? C - 4716 : C - 4715; } p->validYMD = 1; } /* ** Compute the Hour, Minute, and Seconds from the julian day number. */ static void computeHMS(DateTime *p){ int Z, s; if( p->validHMS ) return; Z = p->rJD + 0.5; s = (p->rJD + 0.5 - Z)*86400000.0 + 0.5; p->s = 0.001*s; s = p->s; p->s -= s; p->h = s/3600; s -= p->h*3600; p->m = s/60; p->s += s - p->m*60; p->validHMS = 1; } /* ** Compute both YMD and HMS */ static void computeYMD_HMS(DateTime *p){ computeYMD(p); computeHMS(p); } /* ** Clear the YMD and HMS and the TZ */ static void clearYMD_HMS_TZ(DateTime *p){ p->validYMD = 0; p->validHMS = 0; p->validTZ = 0; } /* ** Compute the difference (in days) between localtime and UTC (a.k.a. GMT) ** for the time value p where p is in UTC. */ static double localtimeOffset(DateTime *p){ DateTime x, y; time_t t; struct tm *pTm; x = *p; computeYMD_HMS(&x); if( x.Y<1971 || x.Y>=2038 ){ x.Y = 2000; x.M = 1; x.D = 1; x.h = 0; x.m = 0; x.s = 0.0; } else { int s = x.s + 0.5; x.s = s; } x.tz = 0; x.validJD = 0; computeJD(&x); t = (x.rJD-2440587.5)*86400.0 + 0.5; sqlite3OsEnterMutex(); pTm = localtime(&t); y.Y = pTm->tm_year + 1900; y.M = pTm->tm_mon + 1; y.D = pTm->tm_mday; y.h = pTm->tm_hour; y.m = pTm->tm_min; y.s = pTm->tm_sec; sqlite3OsLeaveMutex(); y.validYMD = 1; y.validHMS = 1; y.validJD = 0; y.validTZ = 0; computeJD(&y); return y.rJD - x.rJD; } /* ** Process a modifier to a date-time stamp. The modifiers are ** as follows: ** ** NNN days ** NNN hours ** NNN minutes ** NNN.NNNN seconds ** NNN months ** NNN years ** start of month ** start of year ** start of week ** start of day ** weekday N ** unixepoch ** localtime ** utc ** ** Return 0 on success and 1 if there is any kind of error. */ static int parseModifier(const char *zMod, DateTime *p){ int rc = 1; int n; double r; char *z, zBuf[30]; z = zBuf; for(n=0; nrJD += localtimeOffset(p); clearYMD_HMS_TZ(p); rc = 0; } break; } case 'u': { /* ** unixepoch ** ** Treat the current value of p->rJD as the number of ** seconds since 1970. Convert to a real julian day number. */ if( strcmp(z, "unixepoch")==0 && p->validJD ){ p->rJD = p->rJD/86400.0 + 2440587.5; clearYMD_HMS_TZ(p); rc = 0; }else if( strcmp(z, "utc")==0 ){ double c1; computeJD(p); c1 = localtimeOffset(p); p->rJD -= c1; clearYMD_HMS_TZ(p); p->rJD += c1 - localtimeOffset(p); rc = 0; } break; } case 'w': { /* ** weekday N ** ** Move the date to the same time on the next occurrence of ** weekday N where 0==Sunday, 1==Monday, and so forth. If the ** date is already on the appropriate weekday, this is a no-op. */ if( strncmp(z, "weekday ", 8)==0 && getValue(&z[8],&r)>0 && (n=r)==r && n>=0 && r<7 ){ int Z; computeYMD_HMS(p); p->validTZ = 0; p->validJD = 0; computeJD(p); Z = p->rJD + 1.5; Z %= 7; if( Z>n ) Z -= 7; p->rJD += n - Z; clearYMD_HMS_TZ(p); rc = 0; } break; } case 's': { /* ** start of TTTTT ** ** Move the date backwards to the beginning of the current day, ** or month or year. */ if( strncmp(z, "start of ", 9)!=0 ) break; z += 9; computeYMD(p); p->validHMS = 1; p->h = p->m = 0; p->s = 0.0; p->validTZ = 0; p->validJD = 0; if( strcmp(z,"month")==0 ){ p->D = 1; rc = 0; }else if( strcmp(z,"year")==0 ){ computeYMD(p); p->M = 1; p->D = 1; rc = 0; }else if( strcmp(z,"day")==0 ){ rc = 0; } break; } case '+': case '-': case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': { n = getValue(z, &r); if( n<=0 ) break; if( z[n]==':' ){ /* A modifier of the form (+|-)HH:MM:SS.FFF adds (or subtracts) the ** specified number of hours, minutes, seconds, and fractional seconds ** to the time. The ".FFF" may be omitted. The ":SS.FFF" may be ** omitted. */ const char *z2 = z; DateTime tx; int day; if( !isdigit(*(u8*)z2) ) z2++; memset(&tx, 0, sizeof(tx)); if( parseHhMmSs(z2, &tx) ) break; computeJD(&tx); tx.rJD -= 0.5; day = (int)tx.rJD; tx.rJD -= day; if( z[0]=='-' ) tx.rJD = -tx.rJD; computeJD(p); clearYMD_HMS_TZ(p); p->rJD += tx.rJD; rc = 0; break; } z += n; while( isspace(*(u8*)z) ) z++; n = strlen(z); if( n>10 || n<3 ) break; if( z[n-1]=='s' ){ z[n-1] = 0; n--; } computeJD(p); rc = 0; if( n==3 && strcmp(z,"day")==0 ){ p->rJD += r; }else if( n==4 && strcmp(z,"hour")==0 ){ p->rJD += r/24.0; }else if( n==6 && strcmp(z,"minute")==0 ){ p->rJD += r/(24.0*60.0); }else if( n==6 && strcmp(z,"second")==0 ){ p->rJD += r/(24.0*60.0*60.0); }else if( n==5 && strcmp(z,"month")==0 ){ int x, y; computeYMD_HMS(p); p->M += r; x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12; p->Y += x; p->M -= x*12; p->validJD = 0; computeJD(p); y = r; if( y!=r ){ p->rJD += (r - y)*30.0; } }else if( n==4 && strcmp(z,"year")==0 ){ computeYMD_HMS(p); p->Y += r; p->validJD = 0; computeJD(p); }else{ rc = 1; } clearYMD_HMS_TZ(p); break; } default: { break; } } return rc; } /* ** Process time function arguments. argv[0] is a date-time stamp. ** argv[1] and following are modifiers. Parse them all and write ** the resulting time into the DateTime structure p. Return 0 ** on success and 1 if there are any errors. */ static int isDate(int argc, sqlite3_value **argv, DateTime *p){ int i; if( argc==0 ) return 1; if( SQLITE_NULL==sqlite3_value_type(argv[0]) || parseDateOrTime(sqlite3_value_text(argv[0]), p) ) return 1; for(i=1; i