NumberDate.subproj/CFDate.c

   1 /*
   2  * Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*      CFDate.c
  24         Copyright 1998-2002, Apple, Inc. All rights reserved.
  25         Responsibility: Christopher Kane
  26 */
  27
  28 #include <CoreFoundation/CFDate.h>
  29 #include <CoreFoundation/CFTimeZone.h>
  30 #include <CoreFoundation/CFDictionary.h>
  31 #include <CoreFoundation/CFArray.h>
  32 #include <CoreFoundation/CFString.h>
  33 #include <CoreFoundation/CFNumber.h>
  34 #include "CFInternal.h"
  35 #include <math.h>
  36 #if defined(__MACH__) || defined(__LINUX__)
  37     #include <sys/time.h>
  38 #endif
  39 #if defined(__WIN32__)
  40     #include <windows.h>
  41 #endif
  42
  43 const CFTimeInterval kCFAbsoluteTimeIntervalSince1970 = 978307200.0L;
  44 const CFTimeInterval kCFAbsoluteTimeIntervalSince1904 = 3061152000.0L;
  45
  46 /* cjk: The Julian Date for the reference date is 2451910.5,
  47         I think, in case that's ever useful. */
  48
  49 struct __CFDate {
  50     CFRuntimeBase _base;
  51     CFAbsoluteTime _time;       /* immutable */
  52 };
  53
  54 #if defined(__WIN32__)
  55 // We should export this as SPI or API to clients - 3514284
  56 CFAbsoluteTime _CFAbsoluteTimeFromFileTime(const FILETIME *ft) {
  57     CFAbsoluteTime ret = (CFTimeInterval)ft->dwHighDateTime * 429.49672960;
  58     ret += (CFTimeInterval)ft->dwLowDateTime / 10000000.0;
  59     ret -= (11644473600.0 + kCFAbsoluteTimeIntervalSince1970);
  60     /* seconds between 1601 and 1970, 1970 and 2001 */
  61     return ret;
  62 }
  63 #endif
  64
  65 #if defined(__MACH__) || defined(__WIN32__)
  66 static double __CFTSRRate = 0.0;
  67 static double __CF1_TSRRate = 0.0;
  68
  69 __private_extern__ int64_t __CFTimeIntervalToTSR(CFTimeInterval ti) {
  70     return (int64_t)(ti * __CFTSRRate);
  71 }
  72
  73 __private_extern__ CFTimeInterval __CFTSRToTimeInterval(int64_t tsr) {
  74     return (CFTimeInterval)((double)tsr * __CF1_TSRRate);
  75 }
  76 #endif
  77
  78 CFAbsoluteTime CFAbsoluteTimeGetCurrent(void) {
  79     CFAbsoluteTime ret;
  80 #if defined(__MACH__) || defined(__svr4__) || defined(__hpux__) || defined(__LINUX__)
  81     struct timeval tv;
  82     gettimeofday(&tv, NULL);
  83     ret = (CFTimeInterval)tv.tv_sec - kCFAbsoluteTimeIntervalSince1970;
  84     ret += (1.0E-6 * (CFTimeInterval)tv.tv_usec);
  85 #elif defined(__WIN32__)
  86     FILETIME ft;
  87     GetSystemTimeAsFileTime(&ft);
  88     ret = _CFAbsoluteTimeFromFileTime(&ft);
  89 #else
  90 #error CFAbsoluteTimeGetCurrent unimplemented for this platform
  91 #endif
  92     return ret;
  93 }
  94
  95 static Boolean __CFDateEqual(CFTypeRef cf1, CFTypeRef cf2) {
  96     CFDateRef date1 = (CFDateRef)cf1;
  97     CFDateRef date2 = (CFDateRef)cf2;
  98     if (date1->_time != date2->_time) return false;
  99     return true;
 100 }
 101
 102 static CFHashCode __CFDateHash(CFTypeRef cf) {
 103     CFDateRef date = (CFDateRef)cf;
 104     return (CFHashCode)(float)floor(date->_time);
 105 }
 106
 107 static CFStringRef __CFDateCopyDescription(CFTypeRef cf) {
 108     CFDateRef date = (CFDateRef)cf;
 109     return CFStringCreateWithFormat(CFGetAllocator(date), NULL, CFSTR("<CFDate %p [%p]>{time = %0.09g}"), cf, CFGetAllocator(date), date->_time);
 110 }
 111
 112 static CFTypeID __kCFDateTypeID = _kCFRuntimeNotATypeID;
 113
 114 static const CFRuntimeClass __CFDateClass = {
 115     0,
 116     "CFDate",
 117     NULL,       // init
 118     NULL,       // copy
 119     NULL,       // dealloc
 120     __CFDateEqual,
 121     __CFDateHash,
 122     NULL,       //
 123     __CFDateCopyDescription
 124 };
 125
 126 __private_extern__ void __CFDateInitialize(void) {
 127 #if defined(__MACH__)
 128     struct mach_timebase_info info;
 129     mach_timebase_info(&info);
 130     __CFTSRRate = (1.0E9 / (double)info.numer) * (double)info.denom;
 131     __CF1_TSRRate = 1.0 / __CFTSRRate;
 132 #endif
 133 #if defined(__WIN32__)
 134     LARGE_INTEGER freq;
 135     if (!QueryPerformanceFrequency(&freq)) {
 136         HALT;
 137     }
 138     __CFTSRRate = freq.QuadPart;
 139     __CF1_TSRRate = 1.0 / __CFTSRRate;
 140 #endif
 141     __kCFDateTypeID = _CFRuntimeRegisterClass(&__CFDateClass);
 142 }
 143
 144 CFTypeID CFDateGetTypeID(void) {
 145     return __kCFDateTypeID;
 146 }
 147
 148 CFDateRef CFDateCreate(CFAllocatorRef allocator, CFAbsoluteTime at) {
 149     CFDateRef memory;
 150     uint32_t size;
 151     size = sizeof(struct __CFDate) - sizeof(CFRuntimeBase);
 152     memory = _CFRuntimeCreateInstance(allocator, __kCFDateTypeID, size, NULL);
 153     if (NULL == memory) {
 154         return NULL;
 155     }
 156     ((struct __CFDate *)memory)->_time = at;
 157     return memory;
 158 }
 159
 160 CFTimeInterval CFDateGetAbsoluteTime(CFDateRef date) {
 161     CF_OBJC_FUNCDISPATCH0(__kCFDateTypeID, CFTimeInterval, date, "timeIntervalSinceReferenceDate");
 162     __CFGenericValidateType(date, CFDateGetTypeID());
 163     return date->_time;
 164 }
 165
 166 CFTimeInterval CFDateGetTimeIntervalSinceDate(CFDateRef date, CFDateRef otherDate) {
 167     CF_OBJC_FUNCDISPATCH1(__kCFDateTypeID, CFTimeInterval, date, "timeIntervalSinceDate:", otherDate);
 168     __CFGenericValidateType(date, CFDateGetTypeID());
 169     __CFGenericValidateType(otherDate, CFDateGetTypeID());
 170     return date->_time - otherDate->_time;
 171 }
 172
 173 CFComparisonResult CFDateCompare(CFDateRef date, CFDateRef otherDate, void *context) {
 174     CF_OBJC_FUNCDISPATCH1(__kCFDateTypeID, CFComparisonResult, date, "compare:", otherDate);
 175     __CFGenericValidateType(date, CFDateGetTypeID());
 176     __CFGenericValidateType(otherDate, CFDateGetTypeID());
 177     if (date->_time < otherDate->_time) return kCFCompareLessThan;
 178     if (date->_time > otherDate->_time) return kCFCompareGreaterThan;
 179     return kCFCompareEqualTo;
 180 }
 181
 182 CF_INLINE int32_t __CFDoubleModToInt(double d, int32_t modulus) {
 183     int32_t result = (int32_t)(float)floor(d - floor(d / modulus) * modulus);
 184     if (result < 0) result += modulus;
 185     return result;
 186 }
 187
 188 CF_INLINE double __CFDoubleMod(double d, int32_t modulus) {
 189     double result = d - floor(d / modulus) * modulus;
 190     if (result < 0.0) result += (double)modulus;
 191     return result;
 192 }
 193
 194 static const uint8_t daysInMonth[16] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 0, 0, 0};
 195 static const uint16_t daysBeforeMonth[16] = {0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365, 0, 0};
 196 static const uint16_t daysAfterMonth[16] = {365, 334, 306, 275, 245, 214, 184, 153, 122, 92, 61, 31, 0, 0, 0, 0};
 197
 198 static inline bool isleap(int32_t year) {
 199     int32_t y = (year + 1) % 400;       /* correct to nearest multiple-of-400 year, then find the remainder */
 200     if (y < 0) y = -y;
 201     return (0 == (y & 3) && 100 != y && 200 != y && 300 != y);
 202 }
 203
 204 /* year arg is absolute year; Gregorian 2001 == year 0; 2001/1/1 = absolute date 0 */
 205 static inline uint8_t __CFDaysInMonth(int8_t month, int32_t year, bool leap) {
 206     return daysInMonth[month] + (2 == month && leap);
 207 }
 208
 209 /* year arg is absolute year; Gregorian 2001 == year 0; 2001/1/1 = absolute date 0 */
 210 static inline uint16_t __CFDaysBeforeMonth(int8_t month, int32_t year, bool leap) {
 211     return daysBeforeMonth[month] + (2 < month && leap);
 212 }
 213
 214 /* year arg is absolute year; Gregorian 2001 == year 0; 2001/1/1 = absolute date 0 */
 215 static inline uint16_t __CFDaysAfterMonth(int8_t month, int32_t year, bool leap) {
 216     return daysAfterMonth[month] + (month < 2 && leap);
 217 }
 218
 219 /* year arg is absolute year; Gregorian 2001 == year 0; 2001/1/1 = absolute date 0 */
 220 static void __CFYMDFromAbsolute(int32_t absolute, int32_t *year, int8_t *month, int8_t *day) {
 221     int32_t b = absolute / 146097;      // take care of as many multiples of 400 years as possible
 222     int32_t y = b * 400;
 223     uint16_t ydays;
 224     absolute -= b * 146097;
 225     while (absolute < 0) {
 226         y -= 1;
 227         absolute += __CFDaysAfterMonth(0, y, isleap(y));
 228     }
 229     /* Now absolute is non-negative days to add to year */
 230     ydays = __CFDaysAfterMonth(0, y, isleap(y));
 231     while (ydays <= absolute) {
 232         y += 1;
 233         absolute -= ydays;
 234         ydays = __CFDaysAfterMonth(0, y, isleap(y));
 235     }
 236     /* Now we have year and days-into-year */
 237     if (year) *year = y;
 238     if (month || day) {
 239         int8_t m = absolute / 33 + 1; /* search from the approximation */
 240         bool leap = isleap(y);
 241         while (__CFDaysBeforeMonth(m + 1, y, leap) <= absolute) m++;
 242         if (month) *month = m;
 243         if (day) *day = absolute - __CFDaysBeforeMonth(m, y, leap) + 1;
 244     }
 245 }
 246
 247 /* year arg is absolute year; Gregorian 2001 == year 0; 2001/1/1 = absolute date 0 */
 248 static double __CFAbsoluteFromYMD(int32_t year, int8_t month, int8_t day) {
 249     double absolute = 0.0;
 250     int32_t idx;
 251     int32_t b = year / 400; // take care of as many multiples of 400 years as possible
 252     absolute += b * 146097.0;
 253     year -= b * 400;
 254     if (year < 0) {
 255         for (idx = year; idx < 0; idx++)
 256             absolute -= __CFDaysAfterMonth(0, idx, isleap(idx));
 257     } else {
 258         for (idx = 0; idx < year; idx++)
 259             absolute += __CFDaysAfterMonth(0, idx, isleap(idx));
 260     }
 261     /* Now add the days into the original year */
 262     absolute += __CFDaysBeforeMonth(month, year, isleap(year)) + day - 1;
 263     return absolute;
 264 }
 265
 266 Boolean CFGregorianDateIsValid(CFGregorianDate gdate, CFOptionFlags unitFlags) {
 267     if ((unitFlags & kCFGregorianUnitsYears) && (gdate.year <= 0)) return false;
 268     if ((unitFlags & kCFGregorianUnitsMonths) && (gdate.month < 1 || 12 < gdate.month)) return false;
 269     if ((unitFlags & kCFGregorianUnitsDays) && (gdate.day < 1 || 31 < gdate.day)) return false;
 270     if ((unitFlags & kCFGregorianUnitsHours) && (gdate.hour < 0 || 23 < gdate.hour)) return false;
 271     if ((unitFlags & kCFGregorianUnitsMinutes) && (gdate.minute < 0 || 59 < gdate.minute)) return false;
 272     if ((unitFlags & kCFGregorianUnitsSeconds) && (gdate.second < 0.0 || 60.0 <= gdate.second)) return false;
 273     if ((unitFlags & kCFGregorianUnitsDays) && (__CFDaysInMonth(gdate.month, gdate.year - 2001, isleap(gdate.year - 2001)) < gdate.day)) return false;
 274     return true;
 275 }
 276
 277 CFAbsoluteTime CFGregorianDateGetAbsoluteTime(CFGregorianDate gdate, CFTimeZoneRef tz) {
 278     CFAbsoluteTime at;
 279     CFTimeInterval offset0, offset1;
 280     if (NULL != tz) {
 281         __CFGenericValidateType(tz, CFTimeZoneGetTypeID());
 282     }
 283     at = 86400.0 * __CFAbsoluteFromYMD(gdate.year - 2001, gdate.month, gdate.day);
 284     at += 3600.0 * gdate.hour + 60.0 * gdate.minute + gdate.second;
 285     if (NULL != tz) {
 286         offset0 = CFTimeZoneGetSecondsFromGMT(tz, at);
 287         offset1 = CFTimeZoneGetSecondsFromGMT(tz, at - offset0);
 288         at -= offset1;
 289     }
 290     return at;
 291 }
 292
 293 CFGregorianDate CFAbsoluteTimeGetGregorianDate(CFAbsoluteTime at, CFTimeZoneRef tz) {
 294     CFGregorianDate gdate;
 295     int32_t absolute, year;
 296     int8_t month, day;
 297     CFAbsoluteTime fixedat;
 298     if (NULL != tz) {
 299         __CFGenericValidateType(tz, CFTimeZoneGetTypeID());
 300     }
 301     fixedat = at + (NULL != tz ? CFTimeZoneGetSecondsFromGMT(tz, at) : 0.0);
 302     absolute = (int32_t)(float)floor(fixedat / 86400.0);
 303     __CFYMDFromAbsolute(absolute, &year, &month, &day);
 304     gdate.year = year + 2001;
 305     gdate.month = month;
 306     gdate.day = day;
 307     gdate.hour = __CFDoubleModToInt(floor(fixedat / 3600.0), 24);
 308     gdate.minute = __CFDoubleModToInt(floor(fixedat / 60.0), 60);
 309     gdate.second = __CFDoubleMod(fixedat, 60);
 310     return gdate;
 311 }
 312
 313 /* Note that the units of years and months are not equal length, but are treated as such. */
 314 CFAbsoluteTime CFAbsoluteTimeAddGregorianUnits(CFAbsoluteTime at, CFTimeZoneRef tz, CFGregorianUnits units) {
 315     CFGregorianDate gdate;
 316     CFGregorianUnits working;
 317     CFAbsoluteTime candidate_at0, candidate_at1;
 318     uint8_t monthdays;
 319
 320     if (NULL != tz) {
 321         __CFGenericValidateType(tz, CFTimeZoneGetTypeID());
 322     }
 323
 324     /* Most people seem to expect years, then months, then days, etc.
 325         to be added in that order.  Thus, 27 April + (4 days, 1 month)
 326         = 31 May, and not 1 June. This is also relatively predictable.
 327
 328         On another issue, months not being equal length, people also
 329         seem to expect late day-of-month clamping (don't clamp as you
 330         go through months), but clamp before adding in the days. Late
 331         clamping is also more predictable given random starting points
 332         and random numbers of months added (ie Jan 31 + 2 months could
 333         be March 28 or March 29 in different years with aggressive
 334         clamping). Proportionality (28 Feb + 1 month = 31 March) is
 335         also not expected.
 336
 337         Also, people don't expect time zone transitions to have any
 338         effect when adding years and/or months and/or days, only.
 339         Hours, minutes, and seconds, though, are added in as humans
 340         would experience the passing of that time. What this means
 341         is that if the date, after adding years, months, and days
 342         lands on some date, and then adding hours, minutes, and
 343         seconds crosses a time zone transition, the time zone
 344         transition is accounted for. If adding years, months, and
 345         days gets the date into a different time zone offset period,
 346         that transition is not taken into account.
 347     */
 348     gdate = CFAbsoluteTimeGetGregorianDate(at, tz);
 349     /* We must work in a CFGregorianUnits, because the fields in the CFGregorianDate can easily overflow */
 350     working.years = gdate.year;
 351     working.months = gdate.month;
 352     working.days = gdate.day;
 353     working.years += units.years;
 354     working.months += units.months;
 355     while (12 < working.months) {
 356         working.months -= 12;
 357         working.years += 1;
 358     }
 359     while (working.months < 1) {
 360         working.months += 12;
 361         working.years -= 1;
 362     }
 363     monthdays = __CFDaysInMonth(working.months, working.years - 2001, isleap(working.years - 2001));
 364     if (monthdays < working.days) {     /* Clamp day to new month */
 365         working.days = monthdays;
 366     }
 367     working.days += units.days;
 368     while (monthdays < working.days) {
 369         working.months += 1;
 370         if (12 < working.months) {
 371             working.months -= 12;
 372             working.years += 1;
 373         }
 374         working.days -= monthdays;
 375         monthdays = __CFDaysInMonth(working.months, working.years - 2001, isleap(working.years - 2001));
 376     }
 377     while (working.days < 1) {
 378         working.months -= 1;
 379         if (working.months < 1) {
 380             working.months += 12;
 381             working.years -= 1;
 382         }
 383         monthdays = __CFDaysInMonth(working.months, working.years - 2001, isleap(working.years - 2001));
 384         working.days += monthdays;
 385     }
 386     gdate.year = working.years;
 387     gdate.month = working.months;
 388     gdate.day = working.days;
 389     /* Roll in hours, minutes, and seconds */
 390     candidate_at0 = CFGregorianDateGetAbsoluteTime(gdate, tz);
 391     candidate_at1 = candidate_at0 + 3600.0 * units.hours + 60.0 * units.minutes + units.seconds;
 392     /* If summing in the hours, minutes, and seconds delta pushes us
 393      * into a new time zone offset, that will automatically be taken
 394      * care of by the fact that we just add the raw time above. To
 395      * undo that effect, we'd have to get the time zone offsets for
 396      * candidate_at0 and candidate_at1 here, and subtract the
 397      * difference (offset1 - offset0) from candidate_at1. */
 398     return candidate_at1;
 399 }
 400
 401 /* at1 - at2.  The only constraint here is that this needs to be the inverse
 402 of CFAbsoluteTimeByAddingGregorianUnits(), but that's a very rigid constraint.
 403 Unfortunately, due to the nonuniformity of the year and month units, this
 404 inversion essentially has to approximate until it finds the answer. */
 405 CFGregorianUnits CFAbsoluteTimeGetDifferenceAsGregorianUnits(CFAbsoluteTime at1, CFAbsoluteTime at2, CFTimeZoneRef tz, CFOptionFlags unitFlags) {
 406     const int32_t seconds[5] = {366 * 24 * 3600, 31 * 24 * 3600, 24 * 3600, 3600, 60};
 407     CFGregorianUnits units = {0, 0, 0, 0, 0, 0.0};
 408     CFAbsoluteTime atold, atnew = at2;
 409     int32_t idx, incr;
 410     incr = (at2 < at1) ? 1 : -1;
 411     /* Successive approximation: years, then months, then days, then hours, then minutes. */
 412     for (idx = 0; idx < 5; idx++) {
 413         if (unitFlags & (1 << idx)) {
 414             ((int32_t *)&units)[idx] = -3 * incr + (at1 - atnew) / seconds[idx];
 415             do {
 416                 atold = atnew;
 417                 ((int32_t *)&units)[idx] += incr;
 418                 atnew = CFAbsoluteTimeAddGregorianUnits(at2, tz, units);
 419             } while ((1 == incr && atnew <= at1) || (-1 == incr && at1 <= atnew));
 420             ((int32_t *)&units)[idx] -= incr;
 421             atnew = atold;
 422         }
 423     }
 424     if (unitFlags & kCFGregorianUnitsSeconds) {
 425         units.seconds = at1 - atnew;
 426     }
 427     return units;
 428 }
 429
 430 SInt32 CFAbsoluteTimeGetDayOfWeek(CFAbsoluteTime at, CFTimeZoneRef tz) {
 431     int32_t absolute;
 432     CFAbsoluteTime fixedat;
 433     if (NULL != tz) {
 434         __CFGenericValidateType(tz, CFTimeZoneGetTypeID());
 435     }
 436     fixedat = at + (NULL != tz ? CFTimeZoneGetSecondsFromGMT(tz, at) : 0.0);
 437     absolute = (int32_t)(float)floor(fixedat / 86400.0);
 438     return (absolute < 0) ? ((absolute + 1) % 7 + 7) : (absolute % 7 + 1); /* Monday = 1, etc. */
 439 }
 440
 441 SInt32 CFAbsoluteTimeGetDayOfYear(CFAbsoluteTime at, CFTimeZoneRef tz) {
 442     CFAbsoluteTime fixedat;
 443     int32_t absolute, year;
 444     int8_t month, day;
 445     if (NULL != tz) {
 446         __CFGenericValidateType(tz, CFTimeZoneGetTypeID());
 447     }
 448     fixedat = at + (NULL != tz ? CFTimeZoneGetSecondsFromGMT(tz, at) : 0.0);
 449     absolute = (int32_t)(float)floor(fixedat / 86400.0);
 450     __CFYMDFromAbsolute(absolute, &year, &month, &day);
 451     return __CFDaysBeforeMonth(month, year, isleap(year)) + day;
 452 }
 453
 454 /* "the first week of a year is the one which includes the first Thursday" (ISO 8601) */
 455 SInt32 CFAbsoluteTimeGetWeekOfYear(CFAbsoluteTime at, CFTimeZoneRef tz) {
 456     int32_t absolute, year;
 457     int8_t month, day;
 458     CFAbsoluteTime fixedat;
 459     if (NULL != tz) {
 460         __CFGenericValidateType(tz, CFTimeZoneGetTypeID());
 461     }
 462     fixedat = at + (NULL != tz ? CFTimeZoneGetSecondsFromGMT(tz, at) : 0.0);
 463     absolute = (int32_t)(float)floor(fixedat / 86400.0);
 464     __CFYMDFromAbsolute(absolute, &year, &month, &day);
 465     double absolute0101 = __CFAbsoluteFromYMD(year, 1, 1);
 466     int32_t dow0101 = __CFDoubleModToInt(absolute0101, 7) + 1;
 467     /* First three and last three days of a year can end up in a week of a different year */
 468     if (1 == month && day < 4) {
 469         if ((day < 4 && 5 == dow0101) || (day < 3 && 6 == dow0101) || (day < 2 && 7 == dow0101)) {
 470             return 53;
 471         }
 472     }
 473     if (12 == month && 28 < day) {
 474         double absolute20101 = __CFAbsoluteFromYMD(year + 1, 1, 1);
 475         int32_t dow20101 = __CFDoubleModToInt(absolute20101, 7) + 1;
 476         if ((28 < day && 4 == dow20101) || (29 < day && 3 == dow20101) || (30 < day && 2 == dow20101)) {
 477             return 1;
 478         }
 479     }
 480     /* Days into year, plus a week-shifting correction, divided by 7. First week is #1. */
 481     return (__CFDaysBeforeMonth(month, year, isleap(year)) + day + (dow0101 - 11) % 7 + 2) / 7 + 1;
 482 }
 483
 484