FCL/sf/mw/qtwebkit: comparison JavaScriptCore/wtf/DateMath.cpp

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+:4f2f89ce4247
+/*
+* 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)