PHP strtotime函数用法、实现原理和源码分析

    timelib_time *t, *now;
    timelib_tzinfo *tzi;

    tzi = get_timezone_info(TSRMLS_C);

    if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC, “sl”, &times, &time_len, &preset_ts) != FAILURE) {
        /* We have an initial timestamp */
        now = timelib_time_ctor();

        initial_ts = emalloc(25);
        snprintf(initial_ts, 24, “@%ld UTC”, preset_ts);
        t = timelib_strtotime(initial_ts, strlen(initial_ts), NULL, DATE_TIMEZONEDB, php_date_parse_tzfile_wrapper); /* we ignore the error here, as this should never fail */
        timelib_update_ts(t, tzi);
        now->tz_info = tzi;
        now->zone_type = TIMELIB_ZONETYPE_ID;
        timelib_unixtime2local(now, t->sse);
        timelib_time_dtor(t);
        efree(initial_ts);
    } else if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, “s|l”, &times, &time_len, &preset_ts) != FAILURE) {
        /* We have no initial timestamp */
        now = timelib_time_ctor();
        now->tz_info = tzi;
        now->zone_type = TIMELIB_ZONETYPE_ID;
        timelib_unixtime2local(now, (timelib_sll) time(NULL));
    } else {
        RETURN_FALSE;
    }

    if (!time_len) {
        timelib_time_dtor(now);   
        RETURN_FALSE;
    }

    t = timelib_strtotime(times, time_len, &error, DATE_TIMEZONEDB, php_date_parse_tzfile_wrapper);
    error1 = error->error_count;
    timelib_error_container_dtor(error);
    timelib_fill_holes(t, now, TIMELIB_NO_CLONE);
    timelib_update_ts(t, tzi);
    ts = timelib_date_to_int(t, &error2);

    timelib_time_dtor(now);
    timelib_time_dtor(t);

    if (error1 || error2) {
        RETURN_FALSE;
    } else {
        RETURN_LONG(ts);
    }
}
/* }}} */

    //  调用相关函数，实现字符串的解析和结果计算

    //  返回结果
}

    s->time->relative.d = -1;
    TIMELIB_DEINIT;
    return TIMELIB_RELATIVE;
}

    struct timelib_time *time;
    const timelib_tzdb  *tzdb;
} Scanner;

typedef struct timelib_time {
    timelib_sll      y, m, d;     /* Year, Month, Day */
    timelib_sll      h, i, s;     /* Hour, mInute, Second */
    double           f;           /* Fraction */
    int              z;           /* GMT offset in minutes */
    char            *tz_abbr;     /* Timezone abbreviation (display only) */
    timelib_tzinfo  *tz_info;     /* Timezone structure */
    signed int       dst;         /* Flag if we were parsing a DST zone */
    timelib_rel_time relative;

    timelib_sll      sse;         /* Seconds since epoch */

    unsigned int   have_time, have_date, have_zone, have_relative, have_weeknr_day;

    unsigned int   sse_uptodate; /* !0 if the sse member is up to date with the date/time members */
    unsigned int   tim_uptodate; /* !0 if the date/time members are up to date with the sse member */
    unsigned int   is_localtime; /*  1 if the current struct represents localtime, 0 if it is in GMT */
    unsigned int   zone_type;    /*  1 time offset,
                                  *  3 TimeZone identifier,
                                  *  2 TimeZone abbreviation */
} timelib_time;

typedef struct timelib_rel_time {
    timelib_sll y, m, d; /* Years, Months and Days */
    timelib_sll h, i, s; /* Hours, mInutes and Seconds */

    int weekday; /* Stores the day in 'next monday' */
    int weekday_behavior; /* 0: the current day should *not* be counted when advancing forwards; 1: the current day *should* be counted */

    int first_last_day_of;
    int invert; /* Whether the difference should be inverted */
    timelib_sll days; /* Contains the number of *days*, instead of Y-M-D differences */

    timelib_special  special;
    unsigned int   have_weekday_relative, have_special_relative;
} timelib_rel_time;

relnumber = ([+-]*[ \t]*[0-9]+);
relative = relnumber space? (reltextunit | 'week' );