jsdate.c

java script test programing source code

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
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 *
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/*
 * JS date methods.
 */

/*
 * "For example, OS/360 devotes 26 bytes of the permanently
 *  resident date-turnover routine to the proper handling of
 *  December 31 on leap years (when it is Day 366).  That
 *  might have been left to the operator."
 *
 * Frederick Brooks, 'The Second-System Effect'.
 */

#include "jsstddef.h"
#include <ctype.h>
#include <locale.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "jstypes.h"
#include "jsprf.h"
#include "prmjtime.h"
#include "jsutil.h" /* Added by JSIFY */
#include "jsapi.h"
#include "jsconfig.h"
#include "jscntxt.h"
#include "jsdate.h"
#include "jsinterp.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsstr.h"

/*
 * The JS 'Date' object is patterned after the Java 'Date' object.
 * Here is an script:
 *
 *    today = new Date();
 *
 *    print(today.toLocaleString());
 *
 *    weekDay = today.getDay();
 *
 *
 * These Java (and ECMA-262) methods are supported:
 *
 *     UTC
 *     getDate (getUTCDate)
 *     getDay (getUTCDay)
 *     getHours (getUTCHours)
 *     getMinutes (getUTCMinutes)
 *     getMonth (getUTCMonth)
 *     getSeconds (getUTCSeconds)
 *     getMilliseconds (getUTCMilliseconds)
 *     getTime
 *     getTimezoneOffset
 *     getYear
 *     getFullYear (getUTCFullYear)
 *     parse
 *     setDate (setUTCDate)
 *     setHours (setUTCHours)
 *     setMinutes (setUTCMinutes)
 *     setMonth (setUTCMonth)
 *     setSeconds (setUTCSeconds)
 *     setMilliseconds (setUTCMilliseconds)
 *     setTime
 *     setYear (setFullYear, setUTCFullYear)
 *     toGMTString (toUTCString)
 *     toLocaleString
 *     toString
 *
 *
 * These Java methods are not supported
 *
 *     setDay
 *     before
 *     after
 *     equals
 *     hashCode
 */

/*
 * 11/97 - jsdate.c has been rewritten to conform to the ECMA-262 language
 * definition and reduce dependence on NSPR.  NSPR is used to get the current
 * time in milliseconds, the time zone offset, and the daylight savings time
 * offset for a given time.  NSPR is also used for Date.toLocaleString(), for
 * locale-specific formatting, and to get a string representing the timezone.
 * (Which turns out to be platform-dependent.)
 *
 * To do:
 * (I did some performance tests by timing how long it took to run what
 *  I had of the js ECMA conformance tests.)
 *
 * - look at saving results across multiple calls to supporting
 * functions; the toString functions compute some of the same values
 * multiple times.  Although - I took a quick stab at this, and I lost
 * rather than gained.  (Fractionally.)  Hard to tell what compilers/processors
 * are doing these days.
 *
 * - look at tweaking function return types to return double instead
 * of int; this seems to make things run slightly faster sometimes.
 * (though it could be architecture-dependent.)  It'd be good to see
 * how this does on win32.  (Tried it on irix.)  Types could use a
 * general going-over.
 */

/*
 * Supporting functions - ECMA 15.9.1.*
 */

#define HalfTimeDomain  8.64e15
#define HoursPerDay     24.0
#define MinutesPerDay   (HoursPerDay * MinutesPerHour)
#define MinutesPerHour  60.0
#define SecondsPerDay   (MinutesPerDay * SecondsPerMinute)
#define SecondsPerHour  (MinutesPerHour * SecondsPerMinute)
#define SecondsPerMinute 60.0

#if defined(XP_WIN) || defined(XP_OS2)
/* Work around msvc double optimization bug by making these runtime values; if
 * they're available at compile time, msvc optimizes division by them by
 * computing the reciprocal and multiplying instead of dividing - this loses
 * when the reciprocal isn't representable in a double.
 */
static jsdouble msPerSecond = 1000.0;
static jsdouble msPerDay = SecondsPerDay * 1000.0;
static jsdouble msPerHour = SecondsPerHour * 1000.0;
static jsdouble msPerMinute = SecondsPerMinute * 1000.0;
#else
#define msPerDay        (SecondsPerDay * msPerSecond)
#define msPerHour       (SecondsPerHour * msPerSecond)
#define msPerMinute     (SecondsPerMinute * msPerSecond)
#define msPerSecond     1000.0
#endif

#define Day(t)          floor((t) / msPerDay)

static jsdouble
TimeWithinDay(jsdouble t)
{
    jsdouble result;
    result = fmod(t, msPerDay);
    if (result < 0)
        result += msPerDay;
    return result;
}

#define DaysInYear(y)   ((y) % 4 == 0 && ((y) % 100 || ((y) % 400 == 0))  \
                         ? 366 : 365)

/* math here has to be f.p, because we need
 *  floor((1968 - 1969) / 4) == -1
 */
#define DayFromYear(y)  (365 * ((y)-1970) + floor(((y)-1969)/4.0)            \
                         - floor(((y)-1901)/100.0) + floor(((y)-1601)/400.0))
#define TimeFromYear(y) (DayFromYear(y) * msPerDay)

static jsint
YearFromTime(jsdouble t)
{
    jsint y = (jsint) floor(t /(msPerDay*365.2425)) + 1970;
    jsdouble t2 = (jsdouble) TimeFromYear(y);

    if (t2 > t) {
        y--;
    } else {
        if (t2 + msPerDay * DaysInYear(y) <= t)
            y++;
    }
    return y;
}

#define InLeapYear(t)   (JSBool) (DaysInYear(YearFromTime(t)) == 366)

#define DayWithinYear(t, year) ((intN) (Day(t) - DayFromYear(year)))

/*
 * The following array contains the day of year for the first day of
 * each month, where index 0 is January, and day 0 is January 1.
 */
static jsdouble firstDayOfMonth[2][12] = {
    {0.0, 31.0, 59.0, 90.0, 120.0, 151.0, 181.0, 212.0, 243.0, 273.0, 304.0, 334.0},
    {0.0, 31.0, 60.0, 91.0, 121.0, 152.0, 182.0, 213.0, 244.0, 274.0, 305.0, 335.0}
};

#define DayFromMonth(m, leap) firstDayOfMonth[leap][(intN)m];

static intN
MonthFromTime(jsdouble t)
{
    intN d, step;
    jsint year = YearFromTime(t);
    d = DayWithinYear(t, year);

    if (d < (step = 31))
        return 0;
    step += (InLeapYear(t) ? 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 intN
DateFromTime(jsdouble t)
{
    intN d, step, next;
    jsint year = YearFromTime(t);
    d = DayWithinYear(t, year);

    if (d <= (next = 30))
        return d + 1;
    step = next;
    next += (InLeapYear(t) ? 29 : 28);
    if (d <= next)
        return d - step;
    step = next;
    if (d <= (next += 31))
        return d - step;
    step = next;
    if (d <= (next += 30))
        return d - step;
    step = next;
    if (d <= (next += 31))
        return d - step;
    step = next;
    if (d <= (next += 30))
        return d - step;
    step = next;
    if (d <= (next += 31))
        return d - step;
    step = next;
    if (d <= (next += 31))
        return d - step;
    step = next;
    if (d <= (next += 30))
        return d - step;
    step = next;
    if (d <= (next += 31))
        return d - step;
    step = next;
    if (d <= (next += 30))
        return d - step;
    step = next;
    return d - step;
}

static intN
WeekDay(jsdouble t)
{
    jsint result;
    result = (jsint) Day(t) + 4;
    result = result % 7;
    if (result < 0)
        result += 7;
    return (intN) result;
}

#define MakeTime(hour, min, sec, ms) \
((((hour) * MinutesPerHour + (min)) * SecondsPerMinute + (sec)) * msPerSecond + (ms))

static jsdouble
MakeDay(jsdouble year, jsdouble month, jsdouble date)
{
    JSBool leap;
    jsdouble yearday;
    jsdouble monthday;

    year += floor(month / 12);

    month = fmod(month, 12.0);
    if (month < 0)
        month += 12;

    leap = (DaysInYear((jsint) year) == 366);

    yearday = floor(TimeFromYear(year) / msPerDay);
    monthday = DayFromMonth(month, leap);

    return yearday + monthday + date - 1;
}

#define MakeDate(day, time) ((day) * msPerDay + (time))

/*
 * Years and leap years on which Jan 1 is a Sunday, Monday, etc.
 *
 * yearStartingWith[0][i] is an example non-leap year where
 * Jan 1 appears on Sunday (i == 0), Monday (i == 1), etc.
 *
 * yearStartingWith[1][i] is an example leap year where
 * Jan 1 appears on Sunday (i == 0), Monday (i == 1), etc.
 */
static jsint yearStartingWith[2][7] = {
    {1978, 1973, 1974, 1975, 1981, 1971, 1977},
    {1984, 1996, 1980, 1992, 1976, 1988, 1972}
};

/*
 * Find a year for which any given date will fall on the same weekday.
 *
 * This function should be used with caution when used other than
 * for determining DST; it hasn't been proven not to produce an
 * incorrect year for times near year boundaries.
 */
static jsint
EquivalentYearForDST(jsint year)
{
    jsint day;
    JSBool isLeapYear;

    day = (jsint) DayFromYear(year) + 4;
    day = day % 7;
    if (day < 0)
        day += 7;

    isLeapYear = (DaysInYear(year) == 366);

    return yearStartingWith[isLeapYear][day];
}

/* LocalTZA gets set by js_InitDateClass() */
static jsdouble LocalTZA;

static jsdouble
DaylightSavingTA(jsdouble t)
{
    volatile int64 PR_t;
    int64 ms2us;
    int64 offset;
    jsdouble result;

    /* abort if NaN */
    if (JSDOUBLE_IS_NaN(t))
        return t;

    /*
     * If earlier than 1970 or after 2038, potentially beyond the ken of
     * many OSes, map it to an equivalent year before asking.
     */
    if (t < 0.0 || t > 2145916800000.0) {
        jsint year;
        jsdouble day;

        year = EquivalentYearForDST(YearFromTime(t));
        day = MakeDay(year, MonthFromTime(t), DateFromTime(t));
        t = MakeDate(day, TimeWithinDay(t));
    }

    /* put our t in an LL, and map it to usec for prtime */
    JSLL_D2L(PR_t, t);
    JSLL_I2L(ms2us, PRMJ_USEC_PER_MSEC);
    JSLL_MUL(PR_t, PR_t, ms2us);

    offset = PRMJ_DSTOffset(PR_t);

    JSLL_DIV(offset, offset, ms2us);
    JSLL_L2D(result, offset);
    return result;
}


#define AdjustTime(t)   fmod(LocalTZA + DaylightSavingTA(t), msPerDay)

#define LocalTime(t)    ((t) + AdjustTime(t))

static jsdouble
UTC(jsdouble t)
{
    return t - AdjustTime(t - LocalTZA);
}

static intN
HourFromTime(jsdouble t)
{
    intN result = (intN) fmod(floor(t/msPerHour), HoursPerDay);
    if (result < 0)
        result += (intN)HoursPerDay;
    return result;
}

static intN
MinFromTime(jsdouble t)
{
    intN result = (intN) fmod(floor(t / msPerMinute), MinutesPerHour);
    if (result < 0)
        result += (intN)MinutesPerHour;
    return result;
}

static intN
SecFromTime(jsdouble t)
{