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android / platform / external / qt / 7bfefd596b628604816a01c904428ab99099b10d / . / Windows-4.7.4 / src / 3rdparty / webkit / JavaScriptCore / wtf / DateMath.cpp
blob: ea1fe18dbfb82aebcbea6997eded95ea2558ea15 [file] [log] [blame]
/*
* Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
* Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
* Copyright (C) 2009 Google Inc. All rights reserved.
* Copyright (C) 2007-2009 Torch Mobile, Inc.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Alternatively, the contents of this file may be used under the terms
* of either the Mozilla Public License Version 1.1, found at
* http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
* License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
* (the "GPL"), in which case the provisions of the MPL or the GPL are
* applicable instead of those above. If you wish to allow use of your
* version of this file only under the terms of one of those two
* licenses (the MPL or the GPL) and not to allow others to use your
* version of this file under the LGPL, indicate your decision by
* deletingthe provisions above and replace them with the notice and
* other provisions required by the MPL or the GPL, as the case may be.
* If you do not delete the provisions above, a recipient may use your
* version of this file under any of the LGPL, the MPL or the GPL.
* Copyright 2006-2008 the V8 project authors. All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "DateMath.h"
#include "Assertions.h"
#include "ASCIICType.h"
#include "CurrentTime.h"
#include "MathExtras.h"
#include "StringExtras.h"
#include <algorithm>
#include <limits.h>
#include <limits>
#include <stdint.h>
#include <time.h>
#if HAVE(ERRNO_H)
#include <errno.h>
#endif
#if OS(WINCE)
extern "C" size_t strftime(char * const s, const size_t maxsize, const char * const format, const struct tm * const t);
extern "C" struct tm * localtime(const time_t *timer);
#endif
#if HAVE(SYS_TIME_H)
#include <sys/time.h>
#endif
#if HAVE(SYS_TIMEB_H)
#include <sys/timeb.h>
#endif
#if USE(JSC)
#include "CallFrame.h"
#endif
#define NaN std::numeric_limits<double>::quiet_NaN()
using namespace WTF;
namespace WTF {
/* Constants */
static const double minutesPerDay = 24.0 * 60.0;
static const double secondsPerDay = 24.0 * 60.0 * 60.0;
static const double secondsPerYear = 24.0 * 60.0 * 60.0 * 365.0;
static const double usecPerSec = 1000000.0;
static const double maxUnixTime = 2145859200.0; // 12/31/2037
// ECMAScript asks not to support for a date of which total
// millisecond value is larger than the following value.
// See 15.9.1.14 of ECMA-262 5th edition.
static const double maxECMAScriptTime = 8.64E15;
// Day of year for the first day of each month, where index 0 is January, and day 0 is January 1.
// First for non-leap years, then for leap years.
static const int firstDayOfMonth[2][12] = {
{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334},
{0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335}
};
static inline bool isLeapYear(int year)
{
if (year % 4 != 0)
return false;
if (year % 400 == 0)
return true;
if (year % 100 == 0)
return false;
return true;
}
static inline int daysInYear(int year)
{
return 365 + isLeapYear(year);
}
static inline double daysFrom1970ToYear(int year)
{
// The Gregorian Calendar rules for leap years:
// Every fourth year is a leap year. 2004, 2008, and 2012 are leap years.
// However, every hundredth year is not a leap year. 1900 and 2100 are not leap years.
// Every four hundred years, there's a leap year after all. 2000 and 2400 are leap years.
static const int leapDaysBefore1971By4Rule = 1970 / 4;
static const int excludedLeapDaysBefore1971By100Rule = 1970 / 100;
static const int leapDaysBefore1971By400Rule = 1970 / 400;
const double yearMinusOne = year - 1;
const double yearsToAddBy4Rule = floor(yearMinusOne / 4.0) - leapDaysBefore1971By4Rule;
const double yearsToExcludeBy100Rule = floor(yearMinusOne / 100.0) - excludedLeapDaysBefore1971By100Rule;
const double yearsToAddBy400Rule = floor(yearMinusOne / 400.0) - leapDaysBefore1971By400Rule;
return 365.0 * (year - 1970) + yearsToAddBy4Rule - yearsToExcludeBy100Rule + yearsToAddBy400Rule;
}
static inline double msToDays(double ms)
{
return floor(ms / msPerDay);
}
int msToYear(double ms)
{
int approxYear = static_cast<int>(floor(ms / (msPerDay * 365.2425)) + 1970);
double msFromApproxYearTo1970 = msPerDay * daysFrom1970ToYear(approxYear);
if (msFromApproxYearTo1970 > ms)
return approxYear - 1;
if (msFromApproxYearTo1970 + msPerDay * daysInYear(approxYear) <= ms)
return approxYear + 1;
return approxYear;
}
int dayInYear(double ms, int year)
{
return static_cast<int>(msToDays(ms) - daysFrom1970ToYear(year));
}
static inline double msToMilliseconds(double ms)
{
double result = fmod(ms, msPerDay);
if (result < 0)
result += msPerDay;
return result;
}
// 0: Sunday, 1: Monday, etc.
static inline int msToWeekDay(double ms)
{
int wd = (static_cast<int>(msToDays(ms)) + 4) % 7;
if (wd < 0)
wd += 7;
return wd;
}
static inline int msToSeconds(double ms)
{
double result = fmod(floor(ms / msPerSecond), secondsPerMinute);
if (result < 0)
result += secondsPerMinute;
return static_cast<int>(result);
}
static inline int msToMinutes(double ms)
{
double result = fmod(floor(ms / msPerMinute), minutesPerHour);
if (result < 0)
result += minutesPerHour;
return static_cast<int>(result);
}
static inline int msToHours(double ms)
{
double result = fmod(floor(ms/msPerHour), hoursPerDay);
if (result < 0)
result += hoursPerDay;
return static_cast<int>(result);
}
int monthFromDayInYear(int dayInYear, bool leapYear)
{
const int d = dayInYear;
int step;
if (d < (step = 31))
return 0;
step += (leapYear ? 29 : 28);
if (d < step)
return 1;
if (d < (step += 31))
return 2;
if (d < (step += 30))
return 3;
if (d < (step += 31))
return 4;
if (d < (step += 30))
return 5;
if (d < (step += 31))
return 6;
if (d < (step += 31))
return 7;
if (d < (step += 30))
return 8;
if (d < (step += 31))
return 9;
if (d < (step += 30))
return 10;
return 11;
}
static inline bool checkMonth(int dayInYear, int& startDayOfThisMonth, int& startDayOfNextMonth, int daysInThisMonth)
{
startDayOfThisMonth = startDayOfNextMonth;
startDayOfNextMonth += daysInThisMonth;
return (dayInYear <= startDayOfNextMonth);
}
int dayInMonthFromDayInYear(int dayInYear, bool leapYear)
{
const int d = dayInYear;
int step;
int next = 30;
if (d <= next)
return d + 1;
const int daysInFeb = (leapYear ? 29 : 28);
if (checkMonth(d, step, next, daysInFeb))
return d - step;
if (checkMonth(d, step, next, 31))
return d - step;
if (checkMonth(d, step, next, 30))
return d - step;
if (checkMonth(d, step, next, 31))
return d - step;
if (checkMonth(d, step, next, 30))
return d - step;
if (checkMonth(d, step, next, 31))
return d - step;
if (checkMonth(d, step, next, 31))
return d - step;
if (checkMonth(d, step, next, 30))
return d - step;
if (checkMonth(d, step, next, 31))
return d - step;
if (checkMonth(d, step, next, 30))
return d - step;
step = next;
return d - step;
}
static inline int monthToDayInYear(int month, bool isLeapYear)
{
return firstDayOfMonth[isLeapYear][month];
}
static inline double timeToMS(double hour, double min, double sec, double ms)
{
return (((hour * minutesPerHour + min) * secondsPerMinute + sec) * msPerSecond + ms);
}
double dateToDaysFrom1970(int year, int month, int day)
{
year += month / 12;
month %= 12;
if (month < 0) {
month += 12;
--year;
}
double yearday = floor(daysFrom1970ToYear(year));
ASSERT((year >= 1970 && yearday >= 0) || (year < 1970 && yearday < 0));
int monthday = monthToDayInYear(month, isLeapYear(year));
return yearday + monthday + day - 1;
}
// There is a hard limit at 2038 that we currently do not have a workaround
// for (rdar://problem/5052975).
static inline int maximumYearForDST()
{
return 2037;
}
static inline int minimumYearForDST()
{
// Because of the 2038 issue (see maximumYearForDST) if the current year is
// greater than the max year minus 27 (2010), we want to use the max year
// minus 27 instead, to ensure there is a range of 28 years that all years
// can map to.
return std::min(msToYear(jsCurrentTime()), maximumYearForDST() - 27) ;
}
/*
* Find an equivalent year for the one given, where equivalence is deterined by
* the two years having the same leapness and the first day of the year, falling
* on the same day of the week.
*
* This function returns a year between this current year and 2037, however this
* function will potentially return incorrect results if the current year is after
* 2010, (rdar://problem/5052975), if the year passed in is before 1900 or after
* 2100, (rdar://problem/5055038).
*/
int equivalentYearForDST(int year)
{
// It is ok if the cached year is not the current year as long as the rules
// for DST did not change between the two years; if they did the app would need
// to be restarted.
static int minYear = minimumYearForDST();
int maxYear = maximumYearForDST();
int difference;
if (year > maxYear)
difference = minYear - year;
else if (year < minYear)
difference = maxYear - year;
else
return year;
int quotient = difference / 28;
int product = (quotient) * 28;
year += product;
ASSERT((year >= minYear && year <= maxYear) || (product - year == static_cast<int>(NaN)));
return year;
}
static int32_t calculateUTCOffset()
{
#if PLATFORM(BREWMP)
time_t localTime = static_cast<time_t>(currentTime());
#else
time_t localTime = time(0);
#endif
tm localt;
getLocalTime(&localTime, &localt);
// Get the difference between this time zone and UTC on the 1st of January of this year.
localt.tm_sec = 0;
localt.tm_min = 0;
localt.tm_hour = 0;
localt.tm_mday = 1;
localt.tm_mon = 0;
// Not setting localt.tm_year!
localt.tm_wday = 0;
localt.tm_yday = 0;
localt.tm_isdst = 0;
#if HAVE(TM_GMTOFF)
localt.tm_gmtoff = 0;
#endif
#if HAVE(TM_ZONE)
localt.tm_zone = 0;
#endif
#if HAVE(TIMEGM)
time_t utcOffset = timegm(&localt) - mktime(&localt);
#else
// Using a canned date of 01/01/2009 on platforms with weaker date-handling foo.
localt.tm_year = 109;
time_t utcOffset = 1230768000 - mktime(&localt);
#endif
return static_cast<int32_t>(utcOffset * 1000);
}
/*
* Get the DST offset for the time passed in.
*/
static double calculateDSTOffsetSimple(double localTimeSeconds, double utcOffset)
{
if (localTimeSeconds > maxUnixTime)
localTimeSeconds = maxUnixTime;
else if (localTimeSeconds < 0) // Go ahead a day to make localtime work (does not work with 0)
localTimeSeconds += secondsPerDay;
//input is UTC so we have to shift back to local time to determine DST thus the + getUTCOffset()
double offsetTime = (localTimeSeconds * msPerSecond) + utcOffset;
// Offset from UTC but doesn't include DST obviously
int offsetHour = msToHours(offsetTime);
int offsetMinute = msToMinutes(offsetTime);
// FIXME: time_t has a potential problem in 2038
time_t localTime = static_cast<time_t>(localTimeSeconds);
tm localTM;
getLocalTime(&localTime, &localTM);
double diff = ((localTM.tm_hour - offsetHour) * secondsPerHour) + ((localTM.tm_min - offsetMinute) * 60);
if (diff < 0)
diff += secondsPerDay;
return (diff * msPerSecond);
}
// Get the DST offset, given a time in UTC
static double calculateDSTOffset(double ms, double utcOffset)
{
// On Mac OS X, the call to localtime (see calculateDSTOffsetSimple) will return historically accurate
// DST information (e.g. New Zealand did not have DST from 1946 to 1974) however the JavaScript
// standard explicitly dictates that historical information should not be considered when
// determining DST. For this reason we shift away from years that localtime can handle but would
// return historically accurate information.
int year = msToYear(ms);
int equivalentYear = equivalentYearForDST(year);
if (year != equivalentYear) {
bool leapYear = isLeapYear(year);
int dayInYearLocal = dayInYear(ms, year);
int dayInMonth = dayInMonthFromDayInYear(dayInYearLocal, leapYear);
int month = monthFromDayInYear(dayInYearLocal, leapYear);
double day = dateToDaysFrom1970(equivalentYear, month, dayInMonth);
ms = (day * msPerDay) + msToMilliseconds(ms);
}
return calculateDSTOffsetSimple(ms / msPerSecond, utcOffset);
}
void initializeDates()
{
#ifndef NDEBUG
static bool alreadyInitialized;
ASSERT(!alreadyInitialized);
alreadyInitialized = true;
#endif
equivalentYearForDST(2000); // Need to call once to initialize a static used in this function.
}
static inline double ymdhmsToSeconds(long year, int mon, int day, int hour, int minute, int second)
{
double days = (day - 32075)
+ floor(1461 * (year + 4800.0 + (mon - 14) / 12) / 4)
+ 367 * (mon - 2 - (mon - 14) / 12 * 12) / 12
- floor(3 * ((year + 4900.0 + (mon - 14) / 12) / 100) / 4)
- 2440588;
return ((days * hoursPerDay + hour) * minutesPerHour + minute) * secondsPerMinute + second;
}
// We follow the recommendation of RFC 2822 to consider all
// obsolete time zones not listed here equivalent to "-0000".
static const struct KnownZone {
#if !OS(WINDOWS)
const
#endif
char tzName[4];
int tzOffset;
} known_zones[] = {
{ "UT", 0 },
{ "GMT", 0 },
{ "EST", -300 },
{ "EDT", -240 },
{ "CST", -360 },
{ "CDT", -300 },
{ "MST", -420 },
{ "MDT", -360 },
{ "PST", -480 },
{ "PDT", -420 }
};
inline static void skipSpacesAndComments(const char*& s)
{
int nesting = 0;
char ch;
while ((ch = *s)) {
if (!isASCIISpace(ch)) {
if (ch == '(')
nesting++;
else if (ch == ')' && nesting > 0)
nesting--;
else if (nesting == 0)
break;
}
s++;
}
}
// returns 0-11 (Jan-Dec); -1 on failure
static int findMonth(const char* monthStr)
{
ASSERT(monthStr);
char needle[4];
for (int i = 0; i < 3; ++i) {
if (!*monthStr)
return -1;
needle[i] = static_cast<char>(toASCIILower(*monthStr++));
}
needle[3] = '\0';
const char *haystack = "janfebmaraprmayjunjulaugsepoctnovdec";
const char *str = strstr(haystack, needle);
if (str) {
int position = static_cast<int>(str - haystack);
if (position % 3 == 0)
return position / 3;
}
return -1;
}
static bool parseLong(const char* string, char** stopPosition, int base, long* result)
{
*result = strtol(string, stopPosition, base);
// Avoid the use of errno as it is not available on Windows CE
if (string == *stopPosition || *result == LONG_MIN || *result == LONG_MAX)
return false;
return true;
}
// Odd case where 'exec' is allowed to be 0, to accomodate a caller in WebCore.
static double parseDateFromNullTerminatedCharacters(const char* dateString, bool& haveTZ, int& offset)
{
haveTZ = false;
offset = 0;
// This parses a date in the form:
// Tuesday, 09-Nov-99 23:12:40 GMT
// or
// Sat, 01-Jan-2000 08:00:00 GMT
// or
// Sat, 01 Jan 2000 08:00:00 GMT
// or
// 01 Jan 99 22:00 +0100 (exceptions in rfc822/rfc2822)
// ### non RFC formats, added for Javascript:
// [Wednesday] January 09 1999 23:12:40 GMT
// [Wednesday] January 09 23:12:40 GMT 1999
//
// We ignore the weekday.
// Skip leading space
skipSpacesAndComments(dateString);
long month = -1;
const char *wordStart = dateString;
// Check contents of first words if not number
while (*dateString && !isASCIIDigit(*dateString)) {
if (isASCIISpace(*dateString) || *dateString == '(') {
if (dateString - wordStart >= 3)
month = findMonth(wordStart);
skipSpacesAndComments(dateString);
wordStart = dateString;
} else
dateString++;
}
// Missing delimiter between month and day (like "January29")?
if (month == -1 && wordStart != dateString)
month = findMonth(wordStart);
skipSpacesAndComments(dateString);
if (!*dateString)
return NaN;
// ' 09-Nov-99 23:12:40 GMT'
char* newPosStr;
long day;
if (!parseLong(dateString, &newPosStr, 10, &day))
return NaN;
dateString = newPosStr;
if (!*dateString)
return NaN;
if (day < 0)
return NaN;
long year = 0;
if (day > 31) {
// ### where is the boundary and what happens below?
if (*dateString != '/')
return NaN;
// looks like a YYYY/MM/DD date
if (!*++dateString)
return NaN;
year = day;
if (!parseLong(dateString, &newPosStr, 10, &month))
return NaN;
month -= 1;
dateString = newPosStr;
if (*dateString++ != '/' || !*dateString)
return NaN;
if (!parseLong(dateString, &newPosStr, 10, &day))
return NaN;
dateString = newPosStr;
} else if (*dateString == '/' && month == -1) {
dateString++;
// This looks like a MM/DD/YYYY date, not an RFC date.
month = day - 1; // 0-based
if (!parseLong(dateString, &newPosStr, 10, &day))
return NaN;
if (day < 1 || day > 31)
return NaN;
dateString = newPosStr;
if (*dateString == '/')
dateString++;
if (!*dateString)
return NaN;
} else {
if (*dateString == '-')
dateString++;
skipSpacesAndComments(dateString);
if (*dateString == ',')
dateString++;
if (month == -1) { // not found yet
month = findMonth(dateString);
if (month == -1)
return NaN;
while (*dateString && *dateString != '-' && *dateString != ',' && !isASCIISpace(*dateString))
dateString++;
if (!*dateString)
return NaN;
// '-99 23:12:40 GMT'
if (*dateString != '-' && *dateString != '/' && *dateString != ',' && !isASCIISpace(*dateString))
return NaN;
dateString++;
}
}
if (month < 0 || month > 11)
return NaN;
// '99 23:12:40 GMT'
if (year <= 0 && *dateString) {
if (!parseLong(dateString, &newPosStr, 10, &year))
return NaN;
}
// Don't fail if the time is missing.
long hour = 0;
long minute = 0;
long second = 0;
if (!*newPosStr)
dateString = newPosStr;
else {
// ' 23:12:40 GMT'
if (!(isASCIISpace(*newPosStr) || *newPosStr == ',')) {
if (*newPosStr != ':')
return NaN;
// There was no year; the number was the hour.
year = -1;
} else {
// in the normal case (we parsed the year), advance to the next number
dateString = ++newPosStr;
skipSpacesAndComments(dateString);
}
parseLong(dateString, &newPosStr, 10, &hour);
// Do not check for errno here since we want to continue
// even if errno was set becasue we are still looking
// for the timezone!
// Read a number? If not, this might be a timezone name.
if (newPosStr != dateString) {
dateString = newPosStr;
if (hour < 0 || hour > 23)
return NaN;
if (!*dateString)
return NaN;
// ':12:40 GMT'
if (*dateString++ != ':')
return NaN;
if (!parseLong(dateString, &newPosStr, 10, &minute))
return NaN;
dateString = newPosStr;
if (minute < 0 || minute > 59)
return NaN;
// ':40 GMT'
if (*dateString && *dateString != ':' && !isASCIISpace(*dateString))
return NaN;
// seconds are optional in rfc822 + rfc2822
if (*dateString ==':') {
dateString++;
if (!parseLong(dateString, &newPosStr, 10, &second))
return NaN;
dateString = newPosStr;
if (second < 0 || second > 59)
return NaN;
}
skipSpacesAndComments(dateString);
if (strncasecmp(dateString, "AM", 2) == 0) {
if (hour > 12)
return NaN;
if (hour == 12)
hour = 0;
dateString += 2;
skipSpacesAndComments(dateString);
} else if (strncasecmp(dateString, "PM", 2) == 0) {
if (hour > 12)
return NaN;
if (hour != 12)
hour += 12;
dateString += 2;
skipSpacesAndComments(dateString);
}
}
}
// Don't fail if the time zone is missing.
// Some websites omit the time zone (4275206).
if (*dateString) {
if (strncasecmp(dateString, "GMT", 3) == 0 || strncasecmp(dateString, "UTC", 3) == 0) {
dateString += 3;
haveTZ = true;
}
if (*dateString == '+' || *dateString == '-') {
long o;
if (!parseLong(dateString, &newPosStr, 10, &o))
return NaN;
dateString = newPosStr;
if (o < -9959 || o > 9959)
return NaN;
int sgn = (o < 0) ? -1 : 1;
o = labs(o);
if (*dateString != ':') {
offset = ((o / 100) * 60 + (o % 100)) * sgn;
} else { // GMT+05:00
long o2;
if (!parseLong(dateString, &newPosStr, 10, &o2))
return NaN;
dateString = newPosStr;
offset = (o * 60 + o2) * sgn;
}
haveTZ = true;
} else {
for (int i = 0; i < int(sizeof(known_zones) / sizeof(KnownZone)); i++) {
if (0 == strncasecmp(dateString, known_zones[i].tzName, strlen(known_zones[i].tzName))) {
offset = known_zones[i].tzOffset;
dateString += strlen(known_zones[i].tzName);
haveTZ = true;
break;
}
}
}
}
skipSpacesAndComments(dateString);
if (*dateString && year == -1) {
if (!parseLong(dateString, &newPosStr, 10, &year))
return NaN;
dateString = newPosStr;
}
skipSpacesAndComments(dateString);
// Trailing garbage
if (*dateString)
return NaN;
// Y2K: Handle 2 digit years.
if (year >= 0 && year < 100) {
if (year < 50)
year += 2000;
else
year += 1900;
}
return ymdhmsToSeconds(year, month + 1, day, hour, minute, second) * msPerSecond;
}
double parseDateFromNullTerminatedCharacters(const char* dateString)
{
bool haveTZ;
int offset;
double ms = parseDateFromNullTerminatedCharacters(dateString, haveTZ, offset);
if (isnan(ms))
return NaN;
// fall back to local timezone
if (!haveTZ) {
double utcOffset = calculateUTCOffset();
double dstOffset = calculateDSTOffset(ms, utcOffset);
offset = static_cast<int>((utcOffset + dstOffset) / msPerMinute);
}
return ms - (offset * msPerMinute);
}
double timeClip(double t)
{
if (!isfinite(t))
return NaN;
if (fabs(t) > maxECMAScriptTime)
return NaN;
return trunc(t);
}
} // namespace WTF
#if USE(JSC)
namespace JSC {
// Get the DST offset for the time passed in.
//
// NOTE: The implementation relies on the fact that no time zones have
// more than one daylight savings offset change per month.
// If this function is called with NaN it returns NaN.
static double getDSTOffset(ExecState* exec, double ms, double utcOffset)
{
DSTOffsetCache& cache = exec->globalData().dstOffsetCache;
double start = cache.start;
double end = cache.end;
if (start <= ms) {
// If the time fits in the cached interval, return the cached offset.
if (ms <= end) return cache.offset;
// Compute a possible new interval end.
double newEnd = end + cache.increment;
if (ms <= newEnd) {
double endOffset = calculateDSTOffset(newEnd, utcOffset);
if (cache.offset == endOffset) {
// If the offset at the end of the new interval still matches
// the offset in the cache, we grow the cached time interval
// and return the offset.
cache.end = newEnd;
cache.increment = msPerMonth;
return endOffset;
} else {
double offset = calculateDSTOffset(ms, utcOffset);
if (offset == endOffset) {
// The offset at the given time is equal to the offset at the
// new end of the interval, so that means that we've just skipped
// the point in time where the DST offset change occurred. Updated
// the interval to reflect this and reset the increment.
cache.start = ms;
cache.end = newEnd;
cache.increment = msPerMonth;
} else {
// The interval contains a DST offset change and the given time is
// before it. Adjust the increment to avoid a linear search for
// the offset change point and change the end of the interval.
cache.increment /= 3;
cache.end = ms;
}
// Update the offset in the cache and return it.
cache.offset = offset;
return offset;
}
}
}
// Compute the DST offset for the time and shrink the cache interval
// to only contain the time. This allows fast repeated DST offset
// computations for the same time.
double offset = calculateDSTOffset(ms, utcOffset);
cache.offset = offset;
cache.start = ms;
cache.end = ms;
cache.increment = msPerMonth;
return offset;
}
/*
* Get the difference in milliseconds between this time zone and UTC (GMT)
* NOT including DST.
*/
double getUTCOffset(ExecState* exec)
{
double utcOffset = exec->globalData().cachedUTCOffset;
if (!isnan(utcOffset))
return utcOffset;
exec->globalData().cachedUTCOffset = calculateUTCOffset();
return exec->globalData().cachedUTCOffset;
}
double gregorianDateTimeToMS(ExecState* exec, const GregorianDateTime& t, double milliSeconds, bool inputIsUTC)
{
double day = dateToDaysFrom1970(t.year + 1900, t.month, t.monthDay);
double ms = timeToMS(t.hour, t.minute, t.second, milliSeconds);
double result = (day * WTF::msPerDay) + ms;
if (!inputIsUTC) { // convert to UTC
double utcOffset = getUTCOffset(exec);
result -= utcOffset;
result -= getDSTOffset(exec, result, utcOffset);
}
return result;
}
// input is UTC
void msToGregorianDateTime(ExecState* exec, double ms, bool outputIsUTC, GregorianDateTime& tm)
{
double dstOff = 0.0;
double utcOff = 0.0;
if (!outputIsUTC) {
utcOff = getUTCOffset(exec);
dstOff = getDSTOffset(exec, ms, utcOff);
ms += dstOff + utcOff;
}
const int year = msToYear(ms);
tm.second = msToSeconds(ms);
tm.minute = msToMinutes(ms);
tm.hour = msToHours(ms);
tm.weekDay = msToWeekDay(ms);
tm.yearDay = dayInYear(ms, year);
tm.monthDay = dayInMonthFromDayInYear(tm.yearDay, isLeapYear(year));
tm.month = monthFromDayInYear(tm.yearDay, isLeapYear(year));
tm.year = year - 1900;
tm.isDST = dstOff != 0.0;
tm.utcOffset = static_cast<long>((dstOff + utcOff) / WTF::msPerSecond);
tm.timeZone = NULL;
}
double parseDateFromNullTerminatedCharacters(ExecState* exec, const char* dateString)
{
ASSERT(exec);
bool haveTZ;
int offset;
double ms = WTF::parseDateFromNullTerminatedCharacters(dateString, haveTZ, offset);
if (isnan(ms))
return NaN;
// fall back to local timezone
if (!haveTZ) {
double utcOffset = getUTCOffset(exec);
double dstOffset = getDSTOffset(exec, ms, utcOffset);
offset = static_cast<int>((utcOffset + dstOffset) / WTF::msPerMinute);
}
return ms - (offset * WTF::msPerMinute);
}
} // namespace JSC
#endif // USE(JSC)